Composite Coatings Applied to Fresh and Blanched Chayote (Sechium edule) and Modeling of the Drying Kinetics and Sorption Isotherms

Sustainable methods such as convective drying have regained interest in reducing the loss and waste of food produce. Combined with techniques like blanching and edible coatings, they could serve as useful tools in food processing development. Composite coatings comprising pectin, soy protein isolate, and xanthan gum were optimized using response surface methodology with the Box-Behnken design. This optimization aimed to investigate their effects on the moisture content, water activity, total color, and rehydration ratio of fresh and blanched chayote slices. Additionally, the study explored the modeling of the drying kinetics and sorption isotherms of chayote (Sechium edule) slices. Soy protein and xanthan gum were found to primarily influence the moisture content (ranging from 5.44% to 9.93%), and pectin influenced water activity (033 to 0.53) of the fresh-coated chayote, while pectin affected the aw (2.13-8.28) and rehydration of the blanch-coated chayote. The optimized formulations for both fresh and blanched chayote were utilized to assess the drying kinetics behavior and sorption isotherms. The best fit (R2: 0.996 to 0.999) was achieved with the parabolic model for thin-layer materials. Furthermore, the sorption isotherms of chayote displayed a Type IV behavior, with the BET model being the most suitable for describing the sorption behavior of materials with low water activity. The predicted values offer valuable data for optimizing processing conditions to enhance the quality and stability of dried chayote.

Synergistic mechanism of steam blanching and freezing conditions on the texture of frozen yellow peaches based on macroscopic and microscopic properties

Freezing and blanching are essential processing steps in the production of frozen yellow peaches, inevitably leading to texture softening of the fruit. In this study, the synergistic mechanism of stem blanching, freezing conditions (-20°C, -40°C, -80°C, and liquid nitrogen [-173°C]), and sample sizes (cubes, slices, and half peaches) on macroscopic properties of texture, cellular structure, and ice crystal size distribution of frozen yellow peaches were measured. Blanching enhanced the heat and mass transfer rates in the subsequent freezing process. For nonblanched samples, cell membrane integrity was lost at any freezing rate, causing a significant reduction in textural quality. Slow freezing further exacerbated the texture softening, while the ultra-rapid freezing caused structural rupture. For blanched samples, the half peaches softened the most. The water holding capacity and fracture stress were not significantly affected by changes in freezing rate, although the ice crystal size distribution was more susceptible to the freezing rate. Peach cubes that had undergone blanching and rapid freezing (-80°C) experienced 4% less drip loss than nonblanched samples. However, blanching softened yellow peaches more than any freezing conditions. The implementation of uniform and shorter duration blanching, along with rapid freezing, has been proven to be more effective in preserving the texture of frozen yellow peaches. Optimization of the blanching process may be more important than increasing the freezing rate to improve the textural quality of frozen yellow peaches.

Effects of Blanching, Freezing and Canning on the Carbohydrates in Sweet Corn

Sweet corn is frequently consumed in the US and contains carbohydrates as major macronutrients. This study examined the effects of blanching, freezing, and canning on carbohydrates in sweet corn. Fresh bi-color sweet corn was picked in the field and processed immediately into frozen and canned samples. Simple sugars, starch, and dietary fiber (DF) (including total DF (TDF), insoluble DF (IDF) and two fractions of soluble DF (SDF)) were measured according to the AOAC methods. Additional glycomic analysis including oligosaccharides, monosaccharide composition of total polysaccharides (MCTP) and glycosidic linkage of total polysaccharides (GLTP) were analyzed using UHPLC-MS. Sucrose is the major simple sugar, and IDF is the main contributor to TDF. Sucrose and total simple sugar concentrations were not altered after blanching or freezing but were significantly reduced in canned samples. Kestose was the only oligosaccharide identified in sweet corn and decreased in all heat-treated or frozen samples. Starch content decreased in frozen samples but increased in canned samples. While two SDF fractions did not differ across all samples, blanching, freezing and canning resulted in increases in TDF and IDF. Six monosaccharides were identified as major building blocks of the total polysaccharides from MCTP analysis. Glucose and total monosaccharide concentrations increased in two canned samples. GLTP was also profoundly altered by different food processing methods. This study provided insights into the changes in the content and quality of carbohydrates in sweet corn after food processing. The data are important for accurate assessment of the carbohydrate intake from different sweet corn products.

Influence of Pre-Treatment and Drying Methods on the Quality of Dried Carrot Properties as Snacks

The aim of the current research was to evaluate the effect of pre-treatment and drying methods on the properties of dried carrots. Carrots were blanched (B) (1 or 3 min) or osmotic dehydrated (OD) (15 or 30 min) and dried by either convection (CD), microwave-convection (MW-CD), microwave-vacuum (MVD), or freeze-drying (FD). FD carrots showed the highest dry matter content (93.6-95.8%) and the lowest water activity (0.24-0.38). MVD carrots had lower dry matter content (79.5-95.8%) and two times more water activity (0.447-0.637) than FD. The highest color difference (∆E) in relation to raw material was noted in MVD samples (22-35) and the smallest in CD and FD (7-18), mainly due to the increase in brightness of the dried carrot. In general dried MCD carrot samples were characterized by the highest max force (hardness) (21.6-42.5 N; on average 34.7 N) in the breaking test and the lowest hardness was observed in the CD (10.8 N) ones. Pre-treatment and drying caused a significant decrease in the content of carotenoids (2.0-2.7 times) and chlorophyll (2.7-4.5 times) compared to the fresh carrot but a retention or increase in the total content of phenolics and antioxidant activity, especially in microwave-vacuum-dried carrots with an increase of even 2.7-2.9 times compared to raw material. High phenolic content (195.6-277.4 mg GA/100 g d.m.) was found in pre-osmotic dehydrated samples, and lower phenolic content was found in blanched samples (110.7-189.6 mg GA/100 g d.m.). Significantly, the highest average antioxidant activity was found in microwave-vacuum-dried samples (228.9 µmol Trolox/100 g d.m.). The results of this study indicate that microwave-vacuum-drying as an alternative to freeze-drying, including in combination with thermal or osmotic treatment, is very promising for the production of dried carrot snacks.

Effect of High-Pressure Processing on the Qualities of Carrot Juice during Cold Storage

This study examines the impact of blanching (heating at 85 °C for 60 s), high-pressure processing (HPP) (600 MPa, 3 min, 20 °C), and a combination of both blanching and HPP on the microbiological and chemical qualities, colour, and antioxidant properties of carrot juice stored at 4 °C for 15 days. In terms of microbiological quality, the total plate count (TPC), coliform bacteria, and Salmonella spp. rose rapidly in the control group (untreated) as the storage time increased. However, for the blanching group, these values climbed more gradually, surpassing the microbiological limits for juice beverages (TPC < 4 log CFU/mL, Coliform < 10 MPN/mL, and Salmonella spp. negative) on the 9 days of storage. In contrast, TPC, coliforms, and Salmonella spp. were undetectable in the HPP and blanching/HPP samples throughout the storage period. Additionally, as storage time lengthened, the pH, total soluble solids, and Hunter colour values (L, a, b) diminished in the control and blanching groups, whilst titratable acidity and browning degree intensified. However, the HPP and blanching/HPP noticeably delayed these decreases or increases. Moreover, although the total phenolic content and DPPH radical scavenging ability in the HPP samples remained relatively stable during storage and were lower compared to other groups, the β-carotene content was higher at the end of the storage period. In summary, HPP can effectively deactivate microorganisms in carrot juice, irrespective of whether blanching is applied, and can impede reductions in pH, increases in acidity, and colour changes, ultimately extending the juice's shelf life.

Optimization of the Heat-Drying Conditions of Drone Pupae by Response Surface Methodology (RSM)

Recent research has been conducted on various types of pre-processing methods for insects, including freeze-drying, microwave drying, hot air heat drying, and non-heat drying. This study aimed to identify the factors that have the greatest impact on heat drying conditions and establish the optimal heat drying conditions for drone pupae (Apis melifera L.) using response surface methodology (RSM) to minimize quality changes. Drone pupae were treated under various conditions, including blanching time (53-187 s) (X1), drying temperatures (41.6-58.4 °C) (X2), and drying time (266-434 min) (X3). The effect of these treatments on response variables, including the color parameter (WI, YI, BI, △E, and BD), AV, and TB of the dried drone pupae, was evaluated using a central composite design. The whole design consisted of 20 experimental points carried out in random order, which included eight factorial points, six center points, and six axial points. The optimal drying conditions for drone pupae were determined to be a blanching time of 58 s, a drying temperature of 56.7 °C, and a drying time of 298 min. The response variables were most affected by drying temperature and drying time and to a lesser extent by blanching time. The processed drone pupae using the optimized drying conditions resulted in the color parameters (WI, BI, YI, ΔE, and BD) being found to be 66.67, 21.33, 26.27, 31.27 and 0.13, respectively. And TB (log CFU/g) and AV (mg/g) values were found to be 3.12 and 4.33, respectively. The estimated and actual values for dried drone pupae showed no significant difference (p < 0.05). Comparing the physicochemical and microbiological properties of freeze-dried and optimal heat-dried drone pupae, the L and b value as well as PV were significantly lower in the heat-dried samples, while no significant difference was observed in the a value and AV (p < 0.05). Our study suggests that the model we developed can be applied to the large-scale production of drying conditions for use in the pharmaceutical and food industries.

The Effect of Washing, Blanching and Frozen Storage on Pesticide Residue in Spinach

Spinach (Spinacia oleracea L.) is a representative green leafy vegetable commonly consumed fresh or as a ready-to-cook frozen product, with increasing consumption because of its many health-related properties. Among leafy vegetables, spinach poses a major concern in terms of pesticide residue detection due to common phytotechnical practices. In this study, spinach leaves were treated in the open field with three commercial pesticide formulations containing propamocarb, lambda-cyhalothrin, fluopicolide and chlorantraniliprole at the highest concentration. The effects of the successive processing steps of washing, blanching, freezing and frozen storage were evaluated on the levels of the four pesticide residues and the degradation product (propamocarb n-desmethyl). The washing step caused a reduction of fluopicolide and chlorantraniliprole of -47% and -43%, respectively, while having a mild effect on lambda-cyhalothrin content (+5%). A two-minute blanching step allowed for the reduction of pesticides content ranging from -41% to -4% with respect to the washed sample. Different behaviors were depicted for longer blanching times, mainly for propamocarb, reaching -56% after 10 min of treatment. Processing factors higher than 1 were reported mainly for lambda-cyhalothrin and fluopicolide. Frozen storage led to a slight increase in the pesticide content in samples treated for 6 and 10 min. The optimal blanching treatment for spinach, submitted to freezing and frozen storage, seems to be 2 min at 80 °C.

Effect of Preliminary Treatment by Pulsed Electric Fields and Blanching on the Quality of Fried Sweet Potato Chips

The effects of pulsed electric fields (PEF) and blanching pretreatments on frying kinetics, oil content, color, texture, acrylamide (AA) content, and microstructure have been investigated in this paper. The total PEF pretreatment duration was t_PEF = 0.2 s with an intensity of E = 1 kV/cm; blanching was studied at 85 °C for 5 min. The results demonstrated that pretreatment significantly reduced the moisture ratio and oil content by 25% and 40.33%, respectively. The total color change ΔE value of the pretreated samples was lower than that of the untreated samples. In addition, pretreatment increased the hardness of the sample after frying, and the AA content in the fried samples pretreated with PEF + blanching was reduced by approximately 46.10% (638 μg/kg). Finally, fried sweet potato chips obtained by the combined pretreatment exhibited a smoother and flatter cross-sectional microstructure.

Application of Central Composite Design and Superimposition Approach for Optimization of Drying Parameters of Pretreated Cassava Flour

The primary goals of this study were to identify the influence of temperature and drying time on pretreated cassava flour, as well as the optimal settings for the factors and to analyze the microstructure of cassava flour. The experiment was designed using the response surface methodology with central composite design and the superimposition approach in order to assess the effect of drying temperature (45.85-74.14 °C) and drying time (3.96-11.03 h) and the optimal drying conditions of the cassava flour investigated. Soaking and blanching were applied as pretreatments to freshly sliced cassava tubers. The value moisture content of cassava flour was between 6.22% and 11.07%, whereas the observed whiteness index in cassava flour ranged from 72.62 to 92.67 in all pretreated cassava flour samples. Through analysis of variance, each drying factor, their interaction, and all squared terms had a substantial impact on moisture content and whiteness index. The optimized values for drying temperature and drying time for each pretreated cassava flour were 70 °C and 10 h, respectively. The microstructure showed a non-gelatinized, relatively homogeneous in size and shape sample with pretreatment soaked in distilled water at room temperature. These study results are relevant to the development of more sustainable cassava flour production.

Impact of ultrasonication and blanching as a pre-treatment on quality parameter of dried and rehydrated bitter gourd

Vegetables are owed to the restriction of seasonal availability and regional abundance; it becomes essential that vegetables are preserved safely during the off-season. These existing demands look for dried products with high nutritional and organoleptic properties similar to fresh products. This study aimed to investigate the effect of ultrasonication and blanching before hot air drying on the quality attributes of bitter gourd (Momordica charantia). Dried samples were rehydrated to find the efficiency of pre-treatment and physicochemical properties. M. charantia slices were pre-treated with ultrasonication and blanched and dried at two different temperatures, 50 °C and 60 °C. M. charantia pre-treated using ultrasonication and dried at 60 °C reduces the drying time to 50% and rehydration time to 40% compared to untreated samples. Physico-chemical analysis of ultrasonicated samples revealed to have better retention of moisture (dried - 3.6%, rehydrated - 88%), Colour ΔE (dried - 9.07, rehydrated - 1.6), ascorbic acid (dried - 513, rehydrated - 310 mg/100 g), phenol (dried - 302, rehydrated - 231 GAE mg/100 g) and β-carotene (dried - 68 µg/100 g, rehydrated - 39 µg/100 g) compared to blanching.

Effect of pre-treatment and freezing on the polyphenol oxidase activity and color stability of sliced peaches

BACKGROUND

A study was conducted to determine the polyphenol oxidase (PPO) activity and changes in surface color and hydroxymethylfurfural (HMF) content in fresh and pre-frozen peach slices stored at different temperatures. In this study, fresh (F) and pre-frozen (P) peaches were subjected to one of four treatments: (i) no treatment (N); (ii) blanching in boiling (96 °C ± 4 °C) water (B); (iii) dipping in 2% l-ascorbic acid and 2% citric acid (AC); or (iv) blanching placed in boiling water, cooling and dipping in 2% ascorbic acid and 2% citric acid (BAC). Peaches from each treatment group were held at -7, -9, or - 12 °C for 21 days.

RESULTS

After 21 days of storage, PPO activity and browning was greater in peaches stored at -7 °C than the PPO activity and browning of peaches stored at -9 °C and - 12 °C. Overall, lightness (L*), yellowness (b*), chroma (c*) and hue (h*) decreased while redness (a*) increased during storage. The BAC peaches had less discoloration and lower PPO activity than peach slices exposed to other treatments. Non-enzymatic browning (HMF indicator) was more pronounced for blanched peaches during storage than unblanched peaches. Pretreatment of blanched peaches with ascorbic and citric acid reduced browning during 21 days at frozen storage for peaches held at -9 °C or - 12 °C.

CONCLUSION

Storage at -12 °C significantly reduced browning and HMF formation in both blanched and unblanched peach slices in comparison with -7 °C storage. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Variation of the Nutritional Composition and Bioactive Potential in Edible Macroalga Saccharina latissima Cultivated from Atlantic Canada Subjected to Different Growth and Processing Conditions

Macroalgae are a new food source in the Western world. The purpose of this study was to evaluate the impact of harvest months and food processing on cultivated Saccharina latissima (S. latissima) from Quebec. Seaweeds were harvested in May and June 2019 and processed by blanching, steaming, and drying with a frozen control condition. The chemical (lipids, proteins, ash, carbohydrates, fibers) and mineral (I, K, Na, Ca, Mg, Fe) compositions, the potential bioactive compounds (alginates, fucoidans, laminarans, carotenoids, polyphenols) and in vitro antioxidant potential were investigated. The results showed that May specimens were significantly the richest in proteins, ash, I, Fe, and carotenoids, while June macroalgae contained more carbohydrates. The antioxidant potential of water-soluble extracts (Oxygen Radical Absorbance Capacity [ORAC] analysis-625 µg/mL) showed the highest potential in June samples. Interactions between harvested months and processing were demonstrated. The drying process applied in May specimens appeared to preserve more S. latissima quality, whereas blanching and steaming resulted in a leaching of minerals. Losses of carotenoids and polyphenols were observed with heating treatments. Water-soluble extracts of dried May samples showed the highest antioxidant potential (ORAC analysis) compared to other methods. Thus, the drying process used to treat S. latissima harvested in May seems to be the best that should be selected.

Evaluation of dry microwave and hot water blanching on physicochemical, textural, functional and organoleptic properties of Indian gooseberry (Phyllanthus emblica)

Indian gooseberry (Phyllanthus emblica) is a seasonal and highly nutritious fruit with shorter shelf-life and astringent taste limiting its utilization. The enzymatic browning and flavor loss are major concerns which makes pre-processing a crucial step for further processing. In this context, dry microwave blanching (MWB) was explored as an alternative to hot-water (HW) blanching to reduce its nutrition losses particularly ascorbic acid (AA) and makes it easier for removal of seed kernel. This study focused on the effect of MW power level (200–500 W) and blanching time (50–100 s) on AA content, color attributes (L*, a*, b*), and enzymatic inhibition in Indian gooseberry. The optimized MWB conditions were 294 W MW power with 70 s blanching time providing satisfactory enzymatic inhibition (75.47%), and retention of AA (417.70 mg/100 g pulp) and color attributes (L*: 58.42, a*: 4.57, b*: 26.23). As compared to HWB (80 °C, 5 min), MWB showed least AA degradation, higher total phenolic content and softening percent with less total color difference owing to its shorter processing time and dry blanching. Quantitative descriptive analysis (QDA) demonstrated that raw and MW blanched Indian gooseberries are the most accepted, followed by HW blanched samples. MWB showed better nutrient retention than HWB with easier seed removal showed the application of MW radiation for blanching of other fruits.

Effects of organic and chemical nitrogen fertilization and postharvest treatments on the visual and nutritional quality of fresh-cut celery (Apium graveolens L.) during storage

The shelf life of horticultural commodities depends on pre- and postharvest factors, such as soil fertilization and postharvest handling. The current study aimed to evaluate fresh-cut celery's postharvest quality as affected by the rate and type (organic and chemical) of nitrogen (N) fertilizer and postharvest treatments. Celery ('Tall Utah') crop was grown in a field in Karaj, Iran. The experimental design was a randomized complete block with three replications and seven preharvest (fertilizer), and five postharvest treatments. Organic fertilizers were vermicompost (VER) and bio-organic fertilizer [farmyard and livestock manure plus Trichoderma harzianum (COM)]. Chemical fertilizers were urea (46% N) at high rate [322 kg·ha¹ N (UREA_HIGH)], optimal rate [196 kg·ha^-1 N (UREA_OPT)], and low rate [138 kg·ha^-1 N (UREA_LOW)]; ammonium nitrate [35% N (AN)] at 196 kg·ha^-1 N; and treatment without fertilization was used as a control. Postharvest treatments included plastic packaging (PP), hydrocooling (HC), blanching (B), and edible coating of psyllium seed mucilage (EC). After postharvest treatments, celery petioles were stored (0-2°C, 85%-90% RH) for 4 weeks and evaluated weekly for quality attributes. Organic fertilizers and UREA_LOW were the most effective treatments in reducing the changes in color, weight loss, titratable acidity (TA), pH, and total soluble solids (TSS) of fresh-cut celery. Organic fertilizers enhanced the vitamin C content, total phenols, and antioxidant activity in celeries. As postharvest treatments, hydrocooling, plastic packaging, and blanching maintained chroma and hue values. Blanching had the greatest effect on the L* value. Hydrocooling increased celery's TA, TSS, and vitamin C content and reduced weight loss and pH during storage. Thus, celery quality was improved when grown under low or adequate N fertilization. Hydrocooling was an effective postharvest treatment for preserving fresh-cut celery quality during storage.

Reduction in residual cyantraniliprole levels in spinach after various washing and blanching methods

Pesticides are used to protect crops from pests and diseases. However, as many pesticides are toxic to humans, it is necessary to assess methods that can remove pesticide residues from agricultural products before human consumption. Spinach is consumed immediately after a relatively simple washing and heating process in the Republic of Korea. Cyantraniliprole is used as a systemic insecticide during spinach cultivation, which means it might remain in the crop after processing. Consequently, it is important to assess whether residues can be reduced to levels that are harmless to the human body after processing. This study investigated lowering the residual cyantraniliprole levels in spinach after washing and blanching. The amount of cyantraniliprole residue in the spinach samples sprayed with cyantraniliprole during cultivation was analyzed using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS). The time of each washing and blanching method was set at 1, 3, and 5 min. The residual levels of cyantraniliprole decreased by 15.1–54.6% and 60.1–93.5% based on the washing and blanching methods employed. The most effective washing method to lower residual cyantraniliprole levels was steeping with a neutral detergent, resulting in cyantraniliprole reduction by 42.9–54.6%. When spinach was blanched after steeping washing with a neutral detergent, the largest removal rates of 77.9 and 91.2% were observed after 1 and 3 min of blanching, respectively. Blanching for 5 min after steeping and running washing exhibited the highest reduction rate of 93.5%. Therefore, a considerable amount of cyantraniliprole residue in spinach could be removed by washing or blanching. Based on the results of this study, blanching after steeping washing can be implemented as an effective method of lowering pesticide concentrations in spinach and other crops, thereby reducing their potential toxicity to humans upon consumption.

Effect of Blanching and Boiling on the Secondary Metabolism of Cultivated Cardoon Stalks: A Case Study of the Tuscany Region (Italy)

Cardoon (C. cardunculus var. altilis DC) is commonly cultivated in the Mediterranean area to produce stalks that are consumed once cooked. Before cooking, stalks are usually subjected to blanching, which means they are exposed to darkness for a few weeks. The present work analyzed the effect of field blanching carried out for 40 days in different ways (burying the stalks under soil or covering them with plastic sheet) on the total phenolic content (TPC), phenolic profile, cynaropicrin content (a bitter compound), and antioxidant activity (AA) of two cardoon cultivars. The nutraceutical quality of blanched cardoons was also investigated following boiling. The phenolic profile revealed a higher number of compounds in blanched stalks than in raw ones. The cynaropicrin content decreased in both cultivars after blanching, indicating a sensitivity to dark conditions and the effectiveness of blanching method in reducing its bitterness. The data presented contribute to improving the knowledge about the effect of blanching and boiling on the quality of cardoon stalks.

Influence of Water, NaCl and Citric Acid Soaking Pre-Treatments on Acrylamide Content in French Fries Prepared in Domestic Conditions

The aim of this study was to investigate the influence of some pre-treatment applications toward acrylamide mitigation in potatoes fried in domestic conditions modeled after those found in Romania, by using a pan and a fryer. Before being fried in a pan, potato strips were treated in one of the following ways: soaked in cold water for 15, 60, and 120 min (a); soaked in hot water at different combinations of temperatures and durations (60, 70, 80 °C for 5, 10, 15 min) (b); soaked in a NaCl solution (c), and; in a citric acid solution (d) both solutions of 0.05% and 1% concentration for 30 min. For potatoes fried in a fryer, the (a) pre-treatment and soaking in water at 80 °C for 5, 10, and 15 min were applied. Untreated samples were used as a control. French fries were analyzed in terms of moisture and acrylamide content, color, and texture parameters. The pre-treatments applied reduced the acrylamide content in French fries by 4–97% when fried in the pan and by 25–47% when fried in the fryer. Acrylamide content of French fries was negatively correlated with L* parameter and moisture content and positively correlated with a* parameter. The pre-treatments applied can be used successfully by consumers to reduce acrylamide content.

Effect of Thermal and Non-Thermal Technologies on Kinetics and the Main Quality Parameters of Red Bell Pepper Dried with Convective and Microwave-Convective Methods

The drying process preserves the surplus of perishable food. However, to obtain a good-quality final product, different pretreatments are conducted before drying. Thus, the aim of the study was the evaluation of the effect of thermal (blanching treatments with hot water) and non-thermal technologies (pulsed electric field (PEF) and ultrasound (US)) on the kinetics of the drying process of red bell pepper. The convective and microwave-convective drying were compared based on quality parameters, such as physical (water activity, porosity, rehydration rate, and color) and chemical properties (total phenolic content, total carotenoids content, antioxidant activity, and total sugars content). The results showed that all of the investigated methods reduced drying time. However, the most effective was blanching, followed by PEF and US treatment, regardless of the drying technique. Non-thermal methods allowed for better preservation of bioactive compounds, such as vitamin C in the range of 8.2% to 22.5% or total carotenoid content in the range of 0.4% to 48%, in comparison to untreated dried material. Moreover, PEF-treated red bell peppers exhibited superior antioxidant activity (higher of about 15.2-30.8%) when compared to untreated dried samples, whereas sonication decreased the free radical scavenging potential by ca. 10%. In most cases, the pretreatment influenced the physical properties, such as porosity, color, or rehydration properties. Samples subjected to PEF and US treatment and dried by using a microwave-assisted method exhibited a significantly higher porosity of 2-4 folds in comparison to untreated material; this result was also confirmed by visual inspection of microtomography scans. Among tested methods, blanched samples had the most similar optical properties to untreated materials; however non-thermally treated bell peppers exhibited the highest saturation of the color.

Study of jelly drying cashew apples (Anacardium occidentale L.) processing

Cashew apples, a by-product accrued during the manufacture of cashew nuts, have abundant nutritional values but are not widely utilized due to the presence of substances that cause acrid taste. In this study, we attempted the production of a dried jelly cashew apple product and optimized three main processing stages including blanching, osmotic, and drying. The results showed suitable conditions at 6 mm thickness in the blanching process. The osmotic process recorded a temperature of 35°C, within 1.5 h, the ratio of sugar syrup/ingredient 2:1 with sugar syrup 60 Bx, and the addition of 0.6% citric acid on the total weight of ingredients and 0.02% CaCl2. The drying process at 55°C within 267 min had the highest ascorbic acid content (TAA), total phenolic content (TPC), and content of tannin compounds (TTC) retention. These parameters refer to a product that has good organoleptic acceptability in terms of taste, acrid content, and a high ability to retain major nutrients. Furthermore, the product recovery efficiency is 21.45%. Jelly drying cashew apples (JDC) are formed to help take advantage of by-products, contributing to adding value for the cashew industry.

Comparative Transcriptomic Analysis Provides Novel Insights into the Blanched Stem of Oenanthe javanica

In the agricultural field, blanching is a technique used to obtain tender, sweet, and delicious water dropwort stems by blocking sunlight. The physiological and nutritional parameters of blanched water dropwort have been previously investigated. However, the molecular mechanism of blanching remains unclear. In the present study, we investigated transcriptomic variations for different blanching periods in the stem of water dropwort (pre, mid, post-blanching, and control). The results showed that many genes in pathways, such as photosynthesis, carbon fixation, and phytohormone signal transduction as well as transcription factors (TFs) were significantly dysregulated. Blanched stems of water dropwort showed the higher number of downregulated genes in pathways, such as photosynthesis, antenna protein, carbon fixation in photosynthetic organisms, and porphyrin and chlorophyll metabolism, which ultimately affect the photosynthesis in water dropwort. The genes of hormone signal transduction pathways (ethylene, jasmonic acid, brassinosteroid, and indole-3-acetic acid) showed upregulation in the post-blanched water dropwort plants. Overall, a higher number of genes coding for TFs, such as ERF, BHLH, MYB, zinc-finger, bZIP, and WRKY were overexpressed in blanched samples in comparison with the control. These genes and pathways participate in inducing the length, developmental processes, pale color, and stress tolerance of the blanched stem. Overall, the genes responsive to blanching, which were identified in this study, provide an effective foundation for further studies on the molecular mechanisms of blanching and photosynthesis regulations in water dropwort and other species.

Kinetics of Colour Development during Frying of Potato Pre-Treated with Pulsed Electric Fields and Blanching: Effect of Cultivar

The current research aimed to investigate the effect of pulsed electric fields (1 kV/cm; 50 and 150 kJ/kg) followed by blanching (3 min., 100 °C) on the colour development of potato slices during frying on a kinetic basis. Four potato cultivars 'Crop77', 'Moonlight', 'Nadine', and 'Russet Burbank' with different content of glucose and amino acids were used. Lightness (L* values from colorimeter measurement) was used as a parameter to assess the colour development during frying. The implementation of PEF and blanching as sequential pre-treatment prior to frying for all potato cultivars was found effective in improving their lightness in the fried products. PEF pre-treatment did not change the kinetics of L* reduction during frying (between 150 and 190 °C) which followed first-order reaction kinetics. The estimated reaction rate constant (k) and activation energy (E_a based on Arrhenius equation) for non-PEF and PEF-treated samples were cultivar dependent. The estimated E_a values during the frying of PEF-treated 'Russet Burbank' and 'Crop77' were significantly (p < 0.05) lower (up to 30%) than their non-PEF counterparts, indicating that the change in k value of L* became less temperature dependence during frying. This kinetic study is valuable to aid the optimisation of frying condition in deep-fried potato industries when PEF technology is implemented.

Impact of Blanching, Freezing, and Fermentation on Physicochemical, Microbial, and Sensory Quality of Sugar Kelp (Saccharina latissima)

Low seaweed consumption in the West is due to lack of availability and consumer familiarity. In this study, the effects of preservation processes on quality aspects of Saccharina latissima products were assessed. First, a blanching (100 °C for 1 or 3 min) treatment was used to produce seaweed salad. In a second study, effects of blanching, freezing, and fermentation on kelp quality were assessed and processed kelp was used to produce sauerkraut. Blanching significantly decreased (p ≤ 0.05) the instrumental kelp a* value and firmness. The a* value negatively correlated with overall liking of salads. To prepare sauerkraut, raw, raw/frozen (-20 °C), blanched (100 °C, 1 min), or blanched/frozen kelp were mixed with cabbage, salted, inoculated with starter cultures and fermented. Inconsistent trends in L* values, firmness, and fungi enumeration were observed after fermentation. Consumers evaluated kelp salad (n = 100) and sauerkraut (n = 80) for acceptability. Blanched kelp salad had higher hedonic scores than raw kelp salad. A 100% cabbage sauerkraut control and blanched kelp/cabbage blends were compared; kelp blends were similar to control for appearance, color, and texture but were lower for overall acceptability. Results suggest improved quality and enhanced consumer acceptability of seaweed products with use of minimal processing.

Corrigendum: Phenotypic, Nutritional, and Antioxidant Characterization of Blanched Oenanthe javanica for Preferable Cultivar

[This corrects the article DOI: 10.3389/fpls.2021.639639.].

Onion juice and extracts for the inhibition of enzymatic browning mechanisms in frozen Agaricus bisporus mushrooms

BACKGROUND

The potential of onion juice, as well as extracts of waste (tunic) (5%) and fleshy scale leaves (25%), to inhibit enzymatic browning of frozen Agaricus bisporus was investigated. The onion materials were used for blanching and their effectiveness in conserving integrity and appearance of mushroom fruiting bodies was compared with the currently accepted method of blanching in a sodium metabisulfite (SM) solution.

RESULTS

It was observed that l-phenylalanine content may be a useful indicator of the changes in enzymatic activity during frozen storage, and l-tyrosine may be an indicator of a loss of lightness in color (parameter L*). The enzymes responsible for color changes were mainly monophenolase (MON) and, to a lesser degree, diphenolase (DIP). After being stored frozen for 8 months, these enzymes were detected at a 29:1 (DIP:MON) ratio in untreated mushrooms and a 2:1 (DIP:MON) ratio in mushrooms treated with onion juice.

CONCLUSION

Onion products may be a good alternative to an SM solution. The most effective method to conserve the light color of fruiting bodies was blanching in juice or in an extract of the fleshy scale leaves. The least effective inhibitor of MON was tunic extract, which did, however, cause a favourable increase in the reducing capacity (total polyphenols) and flavonoids. Although the onion waste (tunic) extract changed the color of mushrooms from white to creamy orange, the color of these products was attractive and positively evaluated by panellists. © 2020 Society of Chemical Industry.

Effects of Harvest Maturity, Refrigeration and Blanching Treatments on the Volatile Profiles of Ripe "Tasti-Lee" Tomatoes

The interactive effects of six maturity stages and refrigerated storage (chilling)/blanching (heating) treatments on the volatile profiles of ripe tomatoes were studied. A total of 42 volatiles were identified, of which 19 compounds had odor activity values equal to or greater than 1. Of those, “green” and “leafy” aroma volatiles were most abundant. Chilling and heating treatments both suppressed overall volatile production, with chilling having the greater impact, regardless of harvest maturity. However, fruit harvested at the turning stage had the least volatile suppression by chilling and heating treatments in comparison with fruit harvested earlier or later, mostly in the fatty acid- and phenylalanine-derived volatiles. Volatiles derived from amino acids were promoted by heat treatment for fruit harvested at all maturities, and those derived from carotenoid and phenylalanine pathways and harvested at advanced harvest maturities were stimulated by chilling treatment. Volatile production is generally believed to be improved by delayed harvest, with vine-ripe being optimum. However, opposite results were observed possibly because the later-harvested fruit had longer exposure to open-field weather stress. The best harvest maturity recommendation is the turning stage where fruit developed abundant volatiles and were least impacted by chilling and heating treatments.

Effect of Long-Term Frozen Storage on Health-Promoting Compounds and Antioxidant Capacity in Baby Mustard

This study investigated the effects of blanching and subsequent long-term frozen storage on the retention of health-promoting compounds and antioxidant capacity in frozen lateral buds of baby mustard. Results showed that all glucosinolates were well preserved during frozen storage, and 72.48% of total glucosinolate content was retained in the unblanched treatment group after 8 months, as were chlorophylls, carotenoids, ascorbic acid, total phenolics, soluble sugars, soluble proteins, and antioxidant capacity. The loss of nutritional qualities mainly occurred in the 1st month of frozen storage, and nutritional qualities in the unblanched treatment group were significantly better than those in the blanched treatment group during frozen storage. Blanching before freezing reduced contents of high-content glucosinolates and ascorbic acid, as well as antioxidant capacity levels. Therefore, we recommend using long-term frozen storage to preserve the quality of baby mustard to achieve annual supply, and freezing without blanching.

A combined pH and temperature precipitation step facilitates the purification of tobacco-derived recombinant proteins that are sensitive to extremes of either parameter

Incubation at pH 4.0 or blanching at ∼65°C facilitates the purification of biopharmaceutical proteins from plants by precipitating most of the host cell proteins (HCPs) before chromatography. However, both methods are compatible only with pH or thermostable target proteins whereas many target proteins may irreversibly denature, e.g., at pH < 4.0. Here, we developed a combined pH/temperature treatment for clarified tobacco extracts and intact leaves. The latter were subjected to a blanching procedure, i.e., the submersion into a hot buffer. Using a design of experiments approach we identified conditions that remove ∼70% of HCPs at ∼55°C, using the thermosensitive antibody 2G12 and the pH-sensitive DsRed as model proteins. We found that pH and temperature exerted a combined effect during the precipitation of HCPs in the pH range 5.0-7.0 at 35°C-60°C. For clarified extracts, the temperature required to achieve a DsRed purity threshold of 20% total soluble protein (TSP) increased from 54°C to 63°C when the pH was increased from 6.4 to 7.3. The pH-stable antibody 2G12 was less responsive to the combined treatment, but the purity of 1% TSP was achieved at 35°C instead of 44°C when the pH was reduced from 6.3 to 5.8. When blanching intact leaves, product losses were not exacerbated at pH 4.0. Indeed, the highest DsRed purity (58% TSP) was achieved at this pH, combined with a temperature of 60°C and an incubation time of 30 min. In contrast, the highest 2G12 purity (0.7% TSP) was achieved at pH 5.1 and 40°C with an incubation time of 20 min. Our data suggest that a combined pH/temperature regime can avoid extreme values of either parameter; therefore, broadening the applicability of these simple purification techniques to other recombinant proteins.

Phenotypic, Nutritional, and Antioxidant Characterization of Blanched Oenanthe javanica for Preferable Cultivar

Blanching is a technique used in blocking sunlight for the production of tender, sweet, and delicious stems in the field. This technique is also used in water dropwort (Oenanthe javanica), an important vegetable in East Asia. In China, the steamed stems of water dropwort are prepared with boiled rice. However, the effect of blanching on the nutritional level and antioxidant capacity of water dropwort has not been explored yet. The current study aims to determine the nutrient contents and antioxidant capacities of five cultivars and select the best cultivar. They were mainly compared in terms of phenotypic, physiological, nutritional, and antioxidant levels after blanch cultivation. Results indicate that blanching significantly influenced the phenotype, physiology, and nutritional level of water dropwort in all cultivars. Although few parameters decreased with blanching, starch, sugars, vitamins, minerals, and antioxidant activities increased significantly in the blanched stems in mid- and post-blanching periods. The most noticeable changes were detected in post-blanching samples. Furthermore, the best cultivar (V11E0012) was identified among them. Therefore, blanched water dropwort could be consumed for achieving more nutraceuticals and antioxidants, and cultivar V11E0012 could be recommend for blanching cultivation.

Optimization and Prediction of the Drying and Quality of Turnip Slices by Convective-Infrared Dryer under Various Pretreatments by RSM and ANFIS Methods

Drying can prolong the shelf life of a product by reducing microbial activities while facilitating its transportation and storage by decreasing the product weight and volume. The quality factors of the drying process are among the important issues in the drying of food and agricultural products. In this study, the effects of several independent variables such as the temperature of the drying air (50, 60, and 70 °C) and the thickness of the samples (2, 4, and 6 mm) were studied on the response variables including the quality indices (color difference and shrinkage) and drying factors (drying time, effective moisture diffusivity coefficient, specific energy consumption (SEC), energy efficiency and dryer efficiency) of the turnip slices dried by a hybrid convective-infrared (HCIR) dryer. Before drying, the samples were treated by three pretreatments: microwave (360 W for 2.5 min), ultrasonic (at 30 °C for 10 min) and blanching (at 90 °C for 2 min). The statistical analyses of the data and optimization of the drying process were achieved by the response surface method (RSM) and the response variables were predicted by the adaptive neuro-fuzzy inference system (ANFIS) model. The results indicated that an increase in the dryer temperature and a decline in the thickness of the sample can enhance the evaporation rate of the samples which will decrease the drying time (40–20 min), SEC (from 168.98 to 21.57 MJ/kg), color difference (from 50.59 to 15.38) and shrinkage (from 67.84% to 24.28%) while increasing the effective moisture diffusivity coefficient (from 1.007 × 10⁻⁹ to 8.11 × 10⁻⁹ m²/s), energy efficiency (from 0.89% to 15.23%) and dryer efficiency (from 2.11% to 21.2%). Compared to ultrasonic and blanching, microwave pretreatment increased the energy and drying efficiency; while the variations in the color and shrinkage were the lowest in the ultrasonic pretreatment. The optimal condition involved the temperature of 70 °C and sample thickness of 2 mm with the desirability above 0.89. The ANFIS model also managed to predict the response variables with R² > 0.96.

The Quality of Red Bell Pepper Subjected to Freeze-Drying Preceded by Traditional and Novel Pretreatment

It has been demonstrated previously in the literature that utilization of PEF or a combination of a pulsed electric field (PEF) and ultrasounds (US) can facilitate dehydration processes and improve the quality of dried products even better than the application of thermal methods such as blanching. The aim of the study was to evaluate the quality of red bell pepper subjected to freeze-drying preceded by blanching or PEF or US treatment applied in a single and combined mode. Furthermore, the freeze-drying was preceded by shock freezing or vacuum freezing performed inside the freeze-dryer as a result of pressure drop during the first stage of freeze-drying. All of the analyzed technological variants enhanced the drying kinetics when compared to the intact material. Freeze-dried bell pepper subjected to non-thermal pretreatment exhibited higher vitamin C, total phenolic and carotenoids content than blanched material despite the fact that blanching reduced drying time the most compared to all other analyzed methods.

The Effect of Pre-Treatment (Blanching, Ultrasound and Freezing) on Quality of Freeze-Dried Red Beets

This paper presents the influence of blanching, ultrasonic processing and freezing conditions on selected physical properties of freeze-dried red beet, i.e., water activity, structure, porosity and shrinkage. Red beets subjected to a selected pre-treatment using its various parameters were frozen by three methods and then freeze-dried. Ultrasound reduced the water activity of samples. Blanching in water reduced shrinkage and improved porosity. In addition to the type of pre-treatment applied, the quality was also affected by freezing conditions before drying. Combined freezing resulted in the highest shrinkage and the lowest porosity and water activity. Slowly frozen samples were characterized by the best porosity.

Effect of blanching and freezing on the physical properties, bioactive compounds, and microstructure of garlic (Allium sativum L.)

The aim of this work was to evaluate the impact of blanching on the physical properties of frozen garlic cloves and to explore the relationship between quality changes and microstructure. A short-term blanching treatment (100 °C  for 45 s, 90 °C  for 45 s, and 80 °C  for 60 s) before freezing did not affect the total organosulfur compound content. In a preliminary research, blanching conditions were determined to be 100 °C  for 45 to 80 s. Under these conditions, peroxidase was inactivated, but organosulfur compounds were retained. Mechanical and color tests showed a damaging effect of blanching and freezing on frozen garlic blanched for 60 and 80 s at 100 °C . Compared to frozen fresh garlic, frozen garlic treated by blanching for 45 s at 100 °C  retained 2871.49 ± 200.24 µg/g of allicin, although 81.83% of peroxidase was inactivated; browning and hardness improved by 49.97 and 48.01%, respectively. According to scanning electron microscopy, significant damage to the microstructure was observed in both frozen fresh garlic and frozen garlic after 60 s and 80 s of blanching at 100 °C . Moreover, ¹ H low-field nuclear magnetic resonance (LF-NMR) indicated that blanching for 60 s and 80 s induced an increase in free water in garlic tissues, resulting in further damage after freezing. As peroxidase was efficiently inactivated, the microstructure and organosulfur compounds were better preserved, and blanching treatment at 100 °C  for 45 s before freezing is a potential method for obtaining frozen garlic with high sensory and nutritional qualities. PRACTICAL APPLICATION: Freezing helps to overcome challenges associated with growing seasons and the deterioration of garlic during storage. After frozen garlic is thawed, it is prone to some undesirable changes, such as enzymatic browning and softening. Minimal blanching (45 s at 100 °C ) pretreatment can help to maintain the bioactive compounds of garlic and prevent texture and color deterioration caused by freezing directly.

Effects of different pretreatment methods on the drying characteristics and quality of potatoes

The effects of different pretreatments on the vitamin C content of peeled fresh potato, the drying characteristics, and several quality attributes of dehydrated potatoes were investigated. Citric acid pretreatment (0.1%-0.3%, 10-30 min), steam blanching (100ºC, 1-2 min), and water blanching (95°C, 1-2 min) were found to have no obvious effect on the drying rate of potatoes, whereas temperature was the main influencing factor. In terms of quality of dehydrated diced potato, 20 min of citric acid pretreatment resulted in the highest vitamin C retention and better color. Furthermore, dehydrated potato pretreated with citric acid all showed similar dynamic moisture adsorption curves, namely type II sorption isotherm. The moisture adsorption curves can be well fitted using the Guggenheim-Anderson-deBoer model with R 2 higher than .97.

Assessment of the phytochemical, antioxidant and antibacterial activities of Heteromorpha arborescens (Spreng.) Cham & Schltdl. leaf extracts

Background: Heteromorpha arborescens (Spreng.) Cham. and Schltdl (Apiaceae) is widely used traditionally for the treatment of a wide range of diseases in Southern and Eastern Africa. Although previous studies have reported the biological activities of hexane, ethyl acetate and methanol extracts of H. arborescens leaves, there is no scientific information on the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts. This study is therefore aimed to investigate and compare the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts of H. arborescens leaves. Methods: Phytochemical analysis for the total phenolic, flavonoid, proanthocyanidin, alkaloid and saponin contents of all the fractions were determined by spectroscopic methods, while the free radical scavenging potential of the extracts were evaluated using DPPH, ABTS radical scavenging and total antioxidant capacity assays. Micro dilution method was used to determine the Minimum Inhibitory Concentrations (MIC) of H. arborescens leaf extracts against Bacillus pumilus, Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Results: Total phenol content of the extracts ranged between 15.10 mg GAE/g- 42.50 mg GAE/g, proanthocyanidin was 459-8402.1 mg QE/g, and flavonoid content of 109.24-235.79 mg QE/g. In addition, alkaloids (5.59%) and saponins (23.33%) were present in significant amounts. Based on the IC ₅₀ values, the ethanol extract exhibited the highest total antioxidant activity (0.013 mg/mL) with highest inhibition against DPPH and ABTS radicals (0.06 and 0.049 mg/mL respectively). Considerable antibacterial activities were observed in the acetone, ethanol and blanched extracts with MIC values ranging from 1.563-12.5 mg/mL; however, the aqueous extract was inactive against all the bacteria strains. Conclusion: The study suggests that H. arborescens leaves could be a valuable source of bioactive compounds. Although the blanching process significantly decreased polyphenolic contents and antioxidant activities of the extracts, it increased the antibacterial compounds.

The Effect of Traditional and Non-Thermal Treatments on the Bioactive Compounds and Sugars Content of Red Bell Pepper

The aim of the study was an investigation of the effect of traditional and non-thermal treatment on the bioactive compounds of red bell pepper. As a thermal process, blanching in water and in steam was studied, while for non-thermal the sonication, pulsed electric field treatment and their combination were used in this experiment. The red bell peppers were evaluated based on quality attributes such as: total carotenoids content; polyphenols; vitamin C; antioxidant activity and sugars content. Vitamin C and sugar content were analyzed using liquid chromatography and other measurements were determined based on the spectrophotometric method. Results showed that the blanching in water or in steam reduced bioactive compounds concentration; whereas non-thermal treatments as pulsed electric field (PEF) applied separately or in combination with ultrasound (US + PEF) let to obtain similar or slightly lower content of bioactive compounds in comparison to untreated peppers. When sonication (US) and combined treatment as PEF + US were applied; in most cases reduction of bioactive compounds concentration occurred. This effect was probably related to the effect of relatively long (30 min) ultrasound treatment. The application of appropriate parameters of non-thermal processing is crucial for the high quality of processed material.

Instant Controlled Pressure Drop as Blanching and Texturing Pre-Treatment to Preserve the Antioxidant Compounds of Red Dried Beetroot (Beta vulgaris L.)

Red beetroot is rich in bioactive compounds such as polyphenols, flavonoids, betaxanthins, betacyanins, among others. According to selected processing methods, the bioaccessibility of these compounds could be either enhanced or decreased. This study evaluated the effect of four different drying conditions: (1) Traditional Drying (TD), (2) Swell Drying (SD), (3) DIC Blanching + Traditional Drying (BTD), and (4) DIC Blanching + Swell Drying (BSD) on the antioxidant content and the antioxidant activity of red beetroots. Obtained results showed that in all the cases, by comparing to Traditional Drying (TD), the coupling of a DIC Blanching pre-treatment to a Swell Drying treatment (BSD) maintained or enhanced the preservation of the Total Phenolic Compounds (TPC), the Total Flavonoids Compounds (TFC), the Betanin Concentration (BC), the Trolox Equivalent Antioxidant Capacity (TEAC), and the Free Radical Scavenging Activity by DPPH (IC50) of red beetroots. Various studies have shown that thanks to the expanded and porous structure triggered by the Swell Drying process, it has been possible to achieve better antioxidants extraction and better whole quality. Hence, by coupling DIC as a blanching–steaming pre-treatment, it was possible to preserve better the antioxidant content and the antioxidant activity of red dried beetroots.

Optimization of the formula and processing of a sweet potato leaf powder-based beverage

For the development of a sweet potato leaf powder (SPLP)-based beverage, we investigated the effects of blanching methods on SPLP quality (including color, nutritional and functional compositions and antioxidant activity), and the effects of particle size and stabilizers on suspension stability of final product. The total polyphenol and antioxidant activity of SPLP of uncut group were 1.69 and 1.91 times those of cut group, respectively, and the indices of nutritional quality of copper, manganese and vitamin E of uncut group were significantly greater than cut group. The ultrafine SPLP-produced lowest gravitational sedimentation ratio (49%), indicating it had greatest suspension stability. The optimized formula of SPLP-based beverage was as follows: ultrafine SPLP of uncut group was mixed with 2.5% (w/w, powder basis) xanthan gum, 1% calcium lactate, 2% ascorbic acid, 12% maltodextrin, 20% xylitol, and 0.9% apple essence. The final product had high nutritional value along with consumer-acceptable flavor and texture.

Reducing the High Iodine Content of Saccharina latissima and Improving the Profile of Other Valuable Compounds by Water Blanching

Saccharina latissima contains high amounts of iodine in comparison to other seaweeds. The present study aimed to decrease the iodine content of S. latissima (sugar kelp) by water blanching and freezing to avoid an excess intake of iodine by consumption of sugar kelp. Various blanching conditions were investigated (temperature; 30, 45, 60 and 80 °C, and duration; 2, 30, 120 and 300 s). Some conditions resulted in a significant decrease in iodine content (≥45 °C and ≥30 s). Non-processed S. latissima contained on average 4605 mg iodine kg⁻¹ dw⁻¹ which significantly decreased following the treatments. The lowest content obtained was 293 mg iodine kg⁻¹·dw⁻¹ by water blanching at 80 °C for 120 s. The study also investigated if other valuable compounds were affected during the processing conditions. No significant changes were observed for total lipid and protein, but significant changes were seen for ash. A significant loss of two non-essential amino acids (glutamic acid and alanine) due to the blanching process was found. This also resulted in a protein quality increase as the essential amino acid to total amino acid ratio changed from 42.01 ± 0.59% in fresh seaweed to 48.0 ± 1.2% in blanched seaweed. Moreover, the proportion of eicosapentaenoic acid, α-linolenic acid, polyunsaturated fatty acids, and omega-3 fatty acids (%FAME), and the omega-3 to omega-6 fatty acids ratio was significantly higher in the samples blanched at 60 °C for 300 s compared to the fresh and samples blanched at 45 °C for 30 s. The total phenolic content (TPC) and the radical scavenging activity were significantly higher in treated samples. The results indicate that the processing did not compromise the valuable compounds in focus in this study for S. latissima; they did, however, result in biomass with an improved profile of health beneficial compounds.

Influence of Potato Crisps Processing Parameters on Acrylamide Formation and Bioaccesibility

A fractional factorial design was used to evaluate the effects of temperature, frying time, blanching treatment and the thickness of potato slices on acrylamide content in crisps. The design was used on freshly harvested and four-month stored potatoes. The critical factors found were temperature and frying time, and the interaction between blanching treatment and slice thickness. Once frying conditions were selected, an acrylamide content of 725 and 1030 mg kg-1 was found for non-stored and 4-month stored tubers, with adequate textural parameters in both cases. The difference in concentration is related to storage conditions, which must be controlled in order to control acrylamide levels. Bioaccesibility studies demonstrated that acrylamide concentration remained at 70%, and reductions took place mainly at the intestinal phase, as a result of reaction with nucleophilic compounds.

Improved Physicochemical and Structural Properties of Blueberries by High Hydrostatic Pressure Processing

The use of high pressure on fruits and vegetables is today widely studied as an alternative to the traditional thermal preservation techniques, with the aim of better preserving nutritional and organoleptic properties. The use of high hydrostatic pressures (400–600 MPa; 1–5 min; room temperature) was tested on the physicochemical and structural properties of blueberries, in comparison to raw and blanched samples. High hydrostatic pressures led to higher tissue damages than blanching, related to the intensity of the treatment. The cellular damages resulted in leakage of intracellular components, such as bioactive molecules and enzymes. As a consequence, among the high pressure treatments, the resulting antioxidant activity was higher for samples treated for longer times (5 min). Pectinmethyl esterase (PME), deactivated by blanching, but strongly barotolerant, was more active in blueberries treated with the more intense high pressure conditions. Blueberry texture was better retained after high pressure than blanching, probably because of the PME effect. Blueberry color shifted towards purple tones after all of the treatments, which was more affected by blanching. Principal component analysis revealed the mild impact of high pressure treatments on the organoleptic properties of blueberries.

Physicochemical Properties and Intestinal Health Promoting Water-Insoluble Fiber Enriched Fraction Prepared from Blanched Vegetable Soybean Pod Hulls

Different methods can be used to change the fiber compositions of food, and they consequently affect the physicochemical properties and physiological activities. The present study compared the effects of a blanching treatment on the physicochemical properties of water-insoluble fiber enriched fraction (WIFF) from three varieties of vegetable soybean pod hulls (tea vegetable soybean pod hull, TVSPH; black vegetable soybean pod hull, BVSPH; 305 vegetable soybean pod hulls, 305VSPH) and evaluated their effects on intestinal health in hamsters. Blanching may increase the soluble dietary fiber (SDF) content of WIFF in the 305VSPH variety by solubilizing cell wall components and releasing water-soluble sugars. Thus, the WIFF in the 305VSPH variety after blanching may be composed of cellulose and pectic substances. The WIFF of the blanched 305VSPH (B-305VSPH) variety exhibited the highest physicochemical properties, such as a water-retention capacity (11.7 g/g), oil-holding capacity (9.34 g/g), swelling property (10.8 mL/g), solubility (12.2%), and cation-exchange capacity (221 meq/kg), of the three varieties examined. The supplementation of B-305VSPH WIFF in the diet resulted in significantly (p < 0.05) lower cecal and fecal ammonia; activities of fecal β-d-glucosidase, β-d-glucuronidase, mucinase, and urease; as well as higher cecal total short-chain fatty acids relative to other diets. In addition, microbial analysis suggested that fecal bifidobacteria growth was enhanced by the consumption of B-305VSPH WIFF. Therefore, B-305VSPH WIFF may be applicable as a potential functional ingredient in the food industry for the improvement of intestinal health.

Dehydrofreezing of peach: Blanching, D-sodium erythorbate vacuum infiltration, vacuum dehydration, and nitrogen packaging affect the thawed quality of peach

Peach slices were blanched (BL), vacuum infiltrated with D-sodium erythorbate (SE), predehydrated, and then nitrogen packaged (NP) before freezing to improve their quality. Our results showed that the BL, SE, and NP pretreatments remarkably improved the quality of frozen peaches. Frozen peaches pretreated by SE+NP+BL showed the highest total phenolic content (TPC), total antioxidant capacity (TAC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity after thawing at 20°C for 24 hr. The soluble solids content and firmness of low-maturity peaches dehydrated to 25% dehydration of their weight were 11.1% and 211.2% higher than those of the control samples, respectively, while their drip loss was 71.9% lower than that of the controls. In conclusion, pretreatment by BL, predehydration, SE, and NP before freezing can significantly improve the quality of frozen peaches after thawing. PRACTICAL APPLICATIONS: We believe that our study results have practical applications because the method of vacuum dehydration combined with blanching, nitrogen packaging, and D-sodium erythorbate treatment of peaches maintains their original taste, inhibits color change, and decreases drip loss. This method is suitable for fruit frozen and stored at a commercial freezing temperature of -20°C and does not need advanced equipment or technology. It can be easily carried out during the fruit freezing process and can be applied to other frozen stored fruits besides peaches.

Effect of industrial freezing on the physical and nutritional quality traits in broccoli

Broccoli was blanched and frozen at industrial scale to ascertain the physical and nutritional changes that take place in industrial processing. Colour, texture, ascorbic and dehydroascorbic acids, glucosinolates, phenolic compounds, antioxidant capacity, mineral nutrients and microstructure were evaluated. Blanching and freezing caused a decrease in lightness and firmness. Losses of phenolic compounds and ascorbic acid + dehydroascorbic acid reached about 57% and 30%, respectively. The antioxidant capacity was similar in fresh and treated broccoli, and the glucosinolates remained constant. These results show that frozen broccoli retains antioxidants compounds, vitamin C and glucosinolates even after industrial processing, meaning that industrially frozen broccoli intended for human consumption can be considered rather similar to the fresh product.

Enhancement of phytochemical content and drying efficiency of onions (Allium cepa L.) through blanching

BACKGROUND

This study investigated the effect of blanching (60, 70 and 80 °C for 1, 3, 5 and 10 min) combined with oven drying at 60 °C on the phenolic compounds, antioxidant activity, colour and drying characteristics (drying time, drying rate constant, effective moisture diffusivity and activation energy) of onion slices.

RESULTS

Blanching of onion slices at 60 °C for 3 min and at 70 °C for 1 min prior to drying increased their bioactive compounds and antioxidant activity compared to the control samples and other treatments. Eighteen drying models were evaluated. The Modified Page and two-term exponential models best represented the drying data. The effective diffusivity ranged from 3.32 × 10^-11 m² s^-1 (control) to 5.27 × 10^-11 m² s^-1 , 5.01 × 10^-11 m² s^-1 , and 4.74 × 10^-11 m² s^-1 for onions blanched at 60 °C, 70 °C and 80 °C, respectively. The higher activation energy was observed for the control (unblanched) sample and slightly lower values were found for 1 min- and 3 min-blanched samples, confirming the higher drying efficiency as a result of the blanching pre-treatment.

CONCLUSION

The use of blanching as a pre-treatment before drying of onions resulted in enhanced phytochemical content and drying efficiency. © 2017 Society of Chemical Industry.

Pilot-scale radiofrequency blanching of potato cuboids: heating uniformity

BACKGROUND

Traditional hot water blanching has a slow heat transfer rate, whereas radiofrequency (RF) heating has the advantages of a much faster heating rate and a higher penetration depth. In the present study, RF heating was applied to improve heating uniformity for subsequent blanching experiments involving potato cuboids. Potato cuboids were treated in a pilot-scale, RF heating system (27.12 MHz, 6 kW) under different operating conditions.

RESULTS

The dielectric constant increased first and then decreased with temperature, whereas the loss factor increased as the temperature increased. The results of the present study reveal that the electrode gap, sample height and NaCl solution had significant effects (P < 0.05) on the temperature distribution and heating uniformity of the sample after RF heating. The optimum RF heating uniformity was obtained at an electrode gap of 120 mm, a sample height of 60 mm and when immersed in NaCl solution of 0.5 s m^-1 . The central heating pattern was presented in a sample. Cold spots were located at the edge of the top surface of the sample.

CONCLUSION

The present study shows the great potential of RF heating for the blanching of vegetables. Future studies should aim to determine changes in the texture and nutrient contents of vegetables during RF heating. © 2017 Society of Chemical Industry.

Effect of Guar Gum with Sorbitol Coating on the Properties and Oil Absorption of French Fries

This paper investigated the effects of guar gum with sorbitol coating on the oil absorption of French fries by combined dye oil methods, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results showed that pretreatment of blanching with calcium ions and coating with guar gum and sorbitol could significantly reduce the structural oil (STO) and penetrated surface oil (PSO) of French fries and have no negative effects on its texture and also effectively control the final moisture content (p < 0.05). Compared with control or samples coated with guar gum (blanching with or without calcium ions), the total oil (TO) of French fries with guar gum and sorbitol reduced by 50.8%, 33.1% and 30.6%, respectively. CLSM photographs confirmed that STO significantly reduced after coating with guar gum and sorbitol, followed by PSO. In the process of frying, the coatings of guar gum or guar gum with sorbitol could effectively prevent oil from infiltrating the potato tissue, which can be seen in the SEM photographs. The barrier properties of French fries were enhanced by coating guar gum, and sorbitol was added to avoid pores and cracks. Blanching with calcium ion can significantly reduce the final moisture content of coating French fries.

Blanchability and sensory quality of large runner peanuts blanched in a radiant wall oven using infrared radiation

BACKGROUND

The main factors behind the growing popularity of infrared radiation heating in food processing include its energy efficiency, food quality retention and process speed, as well as the simplicity of equipment. Infrared radiation was employed as an alternative heat treatment to the conventional hot air method used in peanut blanching. The present study aimed to investigate the application of infrared heating for blanching peanuts and determine their blanchability and sensory quality under various processing conditions.

RESULTS

The total blanchabilities (expressed as a percentage of total blanched) of the infrared radiation trials (radiant wall oven) at 343 °C for 1.5 min, 316 °C for 1.5 min, 288 °C for 1.5 min and 343 °C for 1 min did not differ significantly compared to the hot air control trials (impingement oven) at 100 °C for 30 and 20 min. All infrared trials had significantly lower (P < 0.05) numbers of split kernels compared to those of the conventional trials and all blanched peanuts in the experiment remained raw. A descriptive sensory shelf-life study with one control and three infrared samples demonstrated the possible initiation of oxidation for the conventionally blanched sample at 18 weeks of storage at 24 °C (room temperature), with no indication of oxidation in the infrared samples stored at the same temperature.

CONCLUSION

Infrared radiation peanut blanching is a viable alternative to conventional hot air blanching because of the shorter process time and longer shelf-life, as evident from the sensory storage study. © 2017 Society of Chemical Industry.

Oral submucous fibrosis: Newer proposed classification with critical updates in pathogenesis and management strategies

Oral submucous fibrosis (OSMF) is an oral precancerous condition characterized by inflammation and progressive fibrosis of the submucosal tissues resulting in marked rigidity and trismus. OSMF still remains a dilemma to the clinicians due to elusive pathogenesis and less well-defined classification systems. Over the years, many classification systems have been documented in medical literature based on clinical, histopathological, or functional aspects. However, none of these classifications have achieved universal acceptance. Each classification has its own merits and demerits. An attempt is made to provide and update the knowledge of classification system of OSMF so that it can assist the clinicians, beneficial in researches and academics in categorizing this potentially malignant disease for early detection, prompt management, and reducing the mortality. Along with this, pathogenesis and management have also been discussed.

Effect of blanching time on the quality characteristics of elderly-friendly kkakdugi

For the development of elderly-friendly food, the physicochemical properties and preferences of cooked kkakdugi prepared with various blanching times were examined. As fermentation progressed, significant differences in samples were observed with overall decreasing trends of pH, reducing sugar, lightness (L), yellowness (b), and hardness. Titratable acidity, redness (a), and lactic acid increased during the storage time. The preference test showed that the sample blanched for 3 min (SK3) scored the highest in aroma, taste, texture, and overall acceptance. Overall, SK3 was the most preferred as cooked kkakdugi, which helps elderly people suffering from mastication and deglutition.

Changes in total phenolic content and color of bottle gourd (Lagenaria siceraria) juice upon conventional and ohmic blanching

Plant phenolics exist in a complex matrix and require a high separation capacity for analysis. Bottle gourd (BG) was blanched using conventional thermal and alternate thermal ohmic heating methods using different combinations of temperature (60-90°C) and time (1-5min), and the effect of these methods on total phenolic content (TPC) and color was examined. Complete characterization on the basis of the phenolic profile of unblanched, ohmically blanched, and conventionally blanched samples of BG was studied. Gas chromatography-mass spectrometry and Liquid chromatography-mass spectrometry were used to detect volatile and nonvolatile phenolic compounds, respectively. The color profiles of the unblanched and conventionally and ohmically blanched samples were studied via hunterLab colorimeter using L*, a*, and b* coordinates. The highest increase in TPC was observed at 80°C, 4 min and 90°C, 5min in the case of ohmic and conventional blanching, respectively. The conventionally and ohmically blanched samples both produced desirable green-color retention in comparison to the unblanched samples; however, highest retention was observed in the ohmically blanched samples. The ohmically blanched samples exhibited the maximum extraction of phenolic compounds and better color of BG juice in comparison to the other samples.