Innovative non-thermal technologies affecting potato tuber and fried potato quality

Effect of kesse, koseret, and tosign extract treatments on the oxidative stability of oil during the repeated frying of potato chips

Fried food safety and quality are crucial concerns for consumers and the food industry due to the deterioration of oil quality and the loss of sensory properties during repeated frying. The current study investigated the use of leaf extracts from endemic dietary herbs: kesse (Lippia adoensis var. adoensis), koseret (Lippia adoensis var. koseret), and tosign (Thymus schimperi Ronninger) to enhance oil quality during the repeated frying of potato chips. The analysis of various parameters, including free fatty acids (FFA), iodine value (IV), peroxide value (PV), thiobarbituric acid reactive substances (TBARS), viscosity, and color (L*, a*, and b*), was conducted after every 5th frying cycle to assess oil quality. The results revealed significant (p < 0.05) decreases in deterioration markers for oils treated with herb extracts compared to the control oils. Specifically, after 20 frying cycles, oils treated with the dietary herb extracts exhibited lower percentage of FFA (0.63-1.05), IV (51.7-46.7), PV (6.69-7.68), and TBARS (50.27-56.08) compared to the control. The herb-treated oils also maintained lower FFA, PV, and TBARS values throughout the frying cycles and reduced viscosity, while IV gradually decreased. Furthermore, the L* value decreased gradually, and a* and b* values increased as the number of frying cycles increased. The herb extracts provided better protection against degradation compounds compared to BHT-treated and control oils, which was attributed to their lower FFA and PV. Sensory analysis indicated that potato chips fried in kesse extract-treated oil were the most preferred, followed by those treated with tosign extract. These findings highlight the potential application of herb extracts to increasing oil stability during repeated frying cycles, which add value at the interface between culinary excellence and health perspectives. Natural antioxidants from endemic herbs can maintain oil quality, reduce harmful compounds, and enhance the sensory properties of fried foods, making them a promising alternative to synthetic antioxidants.

Developing an Acceptable Nixtamalised Maize Product for South African Consumers: Sensory, Survey and Nutrient Analysis

South Africa produces high-quality maize, yet food insecurity and malnutrition are prevalent. Maize is a staple for most South Africans and is often eaten as pap, gruel cooked from maize meal (corn flour) and water without diet diversification. Considering the reliance on maize in low-income communities, could nixtamalised maize products be developed that are nutritious, homemade and consumer-acceptable? Nixtamalisation could offer a solution. However, its acceptability and nutritional benefits remain in question. We aimed to develop a product using consumer-led methods. Consumer panels evaluated and selected products using overall acceptability (9-point hedonic scale), Just-About-Right (JAR) and penalty analysis. Consumer-acceptable nixtamalised chutney-flavoured maize chips were moderately liked (7.35) and reached acceptable JAR scores (74.2%). The nixtamalised products were liked and liked very much (56%), 61% of panel members agreed and strongly agreed to purchase and prepare, and 50% to consume nixtamalised products. Nutrient analysis of the chutney chips showed high energy (2302 kJ/100 g) and total fats (23.72), of which saturated fats were 11.47%. Total fibre (17.19 g/100 g), protein (6.64 g/100 g), calcium (163.3) and magnesium (53.67 g/100 g) were promising, while high phosphorous (566.00 mg/100 g) may indicate anti-nutrients present. Nixtamalisation can alleviate food insecurity and malnutrition in countries such as South Africa.

Effects of starch-tea polyphenol complexes on the structure features of reconstituted doughs and oil absorption of potato crisps

The structural features of reconstituted doughs play a crucial role in determining the oil uptake properties of fried potato crisps. Wheat starch (WS), corn starch (CS), potato starch (PS), or tapioca starch (TS) and tea polyphenols (TPs) complexes were prepared, and their effects on the physicochemical and structural properties of reconstituted dough and oil uptake of potato crisps were investigated. A denser and consistent network structure was observed in the reconstituted dough produced by PS-TPs and TS-TPs complexes. Thus, the reconstituted dough prepared using PS-TPs and TS-TPs complexes displayed slower water evaporation and less matrix swelling during frying, leading to a denser matrix and limited oil uptake of potato crisps. The potato crisps with PS-TPs and TS-TPs complexes had 20.83 % and 10.15 % lower oil content. Consequently, the starch-TPs complexes can be used to improve the properties of reconstituted doughs and produce fried snacks with lower oil content.

Causal factors concerning the texture of French fries manufactured at industrial scale

In this paper, we review the physical/chemical phenomena, contributing to the final texture of French fries, as occurs in the whole industrial production chain of frozen par-fried fries. Our discussion is organized following a multiscale hierarchy of these causal factors, where we distinguish the molecular, cellular, microstructural, and product levels. Using the same multiscale framework, we also discuss currently available theoretical knowledge, and experimental methods probing the relevant physical/chemical phenomena. We have identified knowledge gaps, and experimental methods are evaluated in terms of the effort and value of their results. With our overviews, we hope to give promising research directions such to arrive at a multiscale model, encompassing all causal factors relevant to the final texture. This multiscale model is the ultimate tool to evaluate process innovations for effects on final textural quality, which can be balanced against the impacts on sustainability and economics.

Dual-Stage ultrasound in deep frying of potato chips; effects on the oil absorption and the quality of fried chips

Potato chips are popular high-consuming ready-to-eat meals in all of the world which specially attract a lot of attention from youth and children. Reducing oil absorption and improving the quality of chips are major undertakings within the industry. This research aimed to find the best ultrasonic bath-based method by investigating the optimal ultrasonic pre-treatment and developing an ultrasound (US) assisted frying system (UAFS) to reduce the oil absorption of potato chips while maintaining an acceptable quality. Through this technique, the potato chips get sonicated during deep frying in hot oil. US-pretreatment at temperatures of 25 °C and 73 °C, along with US-assisted frying, resulted in the minimal amount of oil which may be due to the US creating potential pores during the pre-treatment phase, which then expand further during the subsequent sonication stage. UAFS in combination with US-pretreatment produced more crispy chips due to the fact that the texture of potato slices becomes more porous. UAFS resulted in a decrease in the moisture content of the fried chips attributed to an increase in the effective diffusion coefficient and mass. Pretreating the chips at 73 °C significantly reduce the color change producing brighter product by inactivation of enzymes such as polyphenol oxidase. Finally, the result of TOPSIS optimization based on potato chips properties confirms that US-pretreatment in 73 °C brine followed by frying using UAFS is the best approach. Scanning electron microscope (SEM) images of potato chips also support this issue.

Shelf-Life Enhancement Applying Pulsed Electric Field and High-Pressure Treatments Prior to Osmotic Dehydration of Fresh-Cut Potatoes

From a quality standpoint, it is desirable to preserve the characteristics of fresh-cut potatoes at their peak. However, due to the mechanical tissue damage during the cutting process, potatoes are susceptible to enzymatic browning. This study pertains to the selection of the appropriate osmotic dehydration (OD), high pressure (HP), and pulsed electric fields (PEF) processing conditions leading to effective quality retention of potato cuts. PEF (0.5 kV/cm, 200 pulses) or HP (400 MPa, 1 min) treatments prior to OD (35 °C, 120 min) were found to promote the retention of the overall quality (texture and color) of the samples. The incorporation of anti-browning agents (ascorbic acid and papain) into the osmotic solution improved the color retention, especially when combined with PEF or HP due to increased solid uptake (during OD) as indicated by DEI index (2.30, 1.93, and 2.10 for OD treated 120 min, non-pre-treated, HP pre-treated, and PEF pre-treated samples, respectively). PEF and HP combined with OD and anti-browning agent enrichment are sought to improve the quality and microbial stability of fresh-cut potatoes during refrigerator storage. Untreated fresh-cut potatoes were characterized by color degradation from the 2nd day of storage at 4 °C, and presented microbial growth (total viable counts: 6 log (CFU)/g) at day 6, whereas pre-treated potato samples retained their color and microbiologically stability after 6 days of cold storage (total viable counts, <4 log(CFU)/g).

Toxicity, metabolism, and mitigation strategies of acrylamide: a comprehensive review

Acrylamide, a food-borne chemical toxicant, has raised global concern in recent decades. It mainly originated from reducing sugar and free amino acid interactions in the carbohydrate-rich foodstuffs heated at high temperatures. Due to the neurotoxicity and carcinogenicity of AA, the mechanism of formation, toxic effects on health, and mitigation strategies, including conventional approaches and innovative technologies, have been of great interest since its discovery in food. Potato products (especially French fries and crisps), coffee, and cereals(bread and biscuit) are renowned contributors to AA's daily intake. The best preventive methods discussed in the literature include time/temperature optimization, blanching, enzymatic treatment, yeast treatment, additives, pulsed electric fields, ultrasound, vacuum roasting, air frying, and irradiation, exhibiting a high efficacy in AA elimination in food products.

Antibacterial Activity of Dihydroquercetin Separated from Fructus Polygoni orientalis against Clavibacter michiganensis subsp. sepedonicus via Damaging Cell Membrane

The yield and quality of potato can be severely affected by bacterial ring rot, which is caused by Clavibacter michiganensis subsp. sepedonicus (Cms). Recently, using natural compounds to control bacteria has received more attention. In this study, five antibacterial compounds from ethyl acetate (EtOAc) extract of Fructus Polygoni orientalis (FPO) against Cms were isolated and the most active compound was screened. Five active compounds were identified as 3,3'-di-O-methylellagic acid (1), 3,3'-di-O-methylellagic acid-4-O-β-D-glucopyranoside (2), dihydroquercetin (3), protocatechuic acid (4) and quercetin (5). Compound 3 (dihydroquercetin, DHQ) was confirmed as the most active compound. The diameter of inhibition zone (DIZ), minimum inhibitory concentration (MIC), protective efficiency and curative efficiency of DHQ were 22.50 mm, 0.313 mg/mL, 84.49% and 79.63%, respectively, which exceeded these of thiophanate-methyl (TM) in antibacterial activity assays; this indicated that DHQ had satisfactory antibacterial activities against Cms in vitro and in vivo. Results of cell membrane damage assessments indicated that DHQ could reduce membrane potential (MP), disrupt the cell membrane integrity, and promote the leakage of nucleic acids and proteins. Overall, these findings suggested that DHQ could serve as a promising lead molecular against Cms, which could provide a basis for its further derivatization.

Elevated ozone effects on potato leaf physiology, growth, and yield: a meta-analysis

Potato is an important crop worldwide and threatened by various environmental stresses, including elevated ozone (e[O3]). Here, we conducted a meta-analysis to quantify the effect of e[O3] on potato plants and how it varies depending upon different experimental conditions. Regarding plant growth and biomass, e[O3] significantly decreased shoot biomass by 18% and belowground biomass by 35%, while it increased the leaf area index by 19% and total number of injured leaves by 146%. As for yield, e[O3] significantly decreased the total tuber number by 21%. A relatively pronounced effect of e[O3] on the stomatal conductance was observed when exposure lasted 31-60 days, which was significantly greater than that after exposure lasted 96-311 days. The overall quantity of leaves was mainly decreased by higher (100-150 ppb) than lower (30-80 ppb) concentrations of e[O3] compared to ambient O3. The effect of e[O3] on the total tuber number was significant mainly when exposure lasted 31-90 days and was greater in plants grown in growth chambers than those planted in open-top chambers and glasshouses. The effect of e[O3] stress on physiology, growth, and yield varied among cultivars, with some cultivars showing marked tolerance relative to other cultivars. The findings can guide strategies to manage the negative impacts of e[O3] stress on potato production.

Controlling bacterial biofilm formation by native and methylated lupine 11S globulins

The antibacterial and anti-biofilm activities of the 11S globulins isolated from lupin seeds (Lupinus termis), and its methylated derivative (M11S), were investigated against seven pathogenic gram-positive and gram-negative bacteria. The MIC of 11S ranged from 0.1 to 4.0 μg/ml against 0.025 to 0.50 μg/ml for M11S, excelling some specific antibiotics. The MICs of M11S were 40-80 times lower than some specific antibiotics against gram-positive bacteria and 2-60 times lower than some specific antibiotics against gram-negative bacteria. One MIC of 11S and M11S highly reduced the liquid growth of all tested bacteria during 24 h at 37°C. They also inhibited biofilm formation by 80%-86% and 85%-94%, respectively (gram-positive), and 29%-44% and 43%-50%, respectively (gram-negative). M11S prevented biofilm formation by gram-positive bacteria at minimum biofilm inhibitory concentration (MBIC), 0.025-0.1 μg/ml against 0.1-0.5 μg/ml for gram-negative bacteria, i.e., 4-20 times and 4-7 times anti-biofilm inhibitory action compared with 11S, respectively. Biofilm formation of two bacteria revealed no adhered cells on glass slides for 24 h at 37°C, i.e., was entirely prevented by one MBIC of 11S and M11S. Scanning electron microscopy indicated microbial biofilm deformation under the action of 11S and M11S, indicating their broad specificity and cell membrane-targeted action.

Impact of dormancy periods on some physiological and biochemical indices of potato tubers

Background

Storage of potato tubers is an essential stage of the supply chain, from farm to consumer, to efficiently match supply and demand. However, the quality and yield of potatoes are influenced by physiological changes during storage.

Methods

This study tested the physiological and biochemical indices in three potato varieties (YunSu 108, YunSu 304 and YunSu 306) during their dormancy periods.

Results

Three potato varieties with different dormancy periods were used to follow changes in starch, protein and several enzymes during storage. The starch and sugar content of the long-dormant variety (YunSu 108, LDV) were stable, whereas those of the short-dormant variety (YunSu 306, SDV) were variable. Starch synthase activity in the three varieties was initially high, then decreased; the starch content of LDV was relatively stable, that of the medium-dormant variety (YunSu 304, MDV) increased with storage time and peaked at sprouting, and that of SDV was low but variable. The sucrose synthase activity of LDV was significantly higher (p < 0.05) than MDV and SDV in the middle storage period. Two spikes were observed in the invertase activity of SDV, whereas those of MDV and LDV were stable. The reducing sugar content of LDV increased significantly before sprouting, that of MDV slowly decreased and that of SDV dropped sharply. During the whole storage period, pectinase activity in LDV did not change significantly, whereas pectinase in MDV and SDV decreased. The cellulase and protein contents initially increased and then decreased in LDV, and steadily decreased in MDV and SDV.

Conclusion

The metabolic indices related to starch and sugar in the LDV were relatively stable during storage, whereas those of the SDV varied greatly. SDV showed increased sucrose, reducing sugars and cellulose; LDV PCA plots clustered in the positive quadrant of PC1 and the negative quadrant of PC2, with increased protein, sucrose synthase and starch; MDV had increased soluble starch synthase.

Untargeted Metabolomics Using UHPLC-HRMS Reveals Metabolic Changes of Fresh-Cut Potato during Browning Process

Surface browning plays a major role in the quality loss of fresh-cut potatoes. Untargeted metabolomics were used to understand the metabolic changes of fresh-cut potato during the browning process. Their metabolites were profiled by ultra-high performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS). Data processing and metabolite annotation were completed by Compound Discoverer 3.3 software. Statistical analysis was applied to screen the key metabolites correlating with browning process. Fifteen key metabolites responsible for the browning process were putatively identified. Moreover, after analysis of the metabolic causes of glutamic acid, linolenic acid, glutathione, adenine, 12-OPDA and AMP, we found that the browning process of fresh-cut potatoes was related to the structural dissociation of the membrane, oxidation and reduction reaction and energy shortage. This work provides a reference for further investigation into the mechanism of browning in fresh-cut products.

Preserving Soybean Oil for the Frying of Breaded Butterfly Shrimp Using Natural Rosemary Antioxidant

Fried foods and frying oil are subjects that warrant the attention of researchers because of their high consumption. Indeed, frying conditions make these oils very sensitive to lipid oxidation which deteriorates the quality and nutritional properties of the food. In this study, we examined the effect of rosemary extract (ROE), known for its high antioxidant activity, in soybean oil used to fry breaded butterfly shrimp, by measuring the induction period with OXIPRES, total polar material (TPM), peroxide index (PI), and free fatty acids (FFA). This evaluation was performed in comparison with control oils without antioxidants. The results showed a significant difference between the oils according to the analyzed parameters, especially in the final hours of frying. The treatment of the oil with rosemary extract effectively delayed its oxidation, having lower levels in all the oxidation markers that were analyzed. It was also found that rosemary extract is able to reduce oil consumption by fried foods. Therefore, ROE ensures soybean oil a high stability against oxidation and a longer shelf life, making it a good natural alternative to synthetic antioxidants.

Batter Characteristics and Oil Penetration of Deep-Fried Breaded Fish Nuggets: Effect of Wheat Starch—Gluten Interaction

To understand the effect of the interaction between wheat starch ( $\mathrm{W}\mathrm{S}$ ) and wheat gluten ( $\mathrm{W}\mathrm{G}$ ) on batter characteristics and oil penetration of deep-fried breaded fish nuggets, batters were prepared using a $\mathrm{W}\mathrm{S}$ and $\mathrm{W}\mathrm{G}$ blend at the ratios of 15 : 1, 13 : 1, 11 : 1, 9 : 1, and 7 : 1 $\mathrm{w}/\mathrm{w}$ , respectively, and batter-breaded fish nuggets (BBFNs) were fried at 170°C for 40 s followed by 190°C for 30 s. Moisture adsorption isotherms of $\mathrm{W}\mathrm{S}$ and $\mathrm{W}\mathrm{G}$ , viscosity, rheological behavior, and calorimetric properties of the batters were measured, and pick-up of BBFNs, thermogravimetric properties of the crust, and oil transport were investigated. The moisture absorption capacity of $\mathrm{W}\mathrm{G}$ was higher than $\mathrm{W}\mathrm{S}$ at a low water activity (0.04–0.65), while the opposite trend was observed at a highwater activity (0.65–0.88). As the proportion of $\mathrm{W}\mathrm{S}$ decreased, the viscosity, $G”$ and tan δ of batter, pick-up of BBFNs, temperature and enthalpy change (ΔH) of protein denaturation and $\mathrm{W}\mathrm{S}$ gelatinization, and oil penetration of BBFNs during deep-fat frying, which are decreased until reaching a minimum value at the ratio of 11 : 1 $\mathrm{w}/\mathrm{w}$ , then increased ( $p<0.05$ ). However, G' of batter and thermogravimetry temperatures of crust exhibited the opposite trend. These results proved that the $\mathrm{W}\mathrm{S}$ – $\mathrm{W}\mathrm{G}$ interaction significantly affected the batter characteristics and oil penetration of BBFNs during deep-fat frying, which can be used to guide the manufacturing of low-fat fried BBFNs.

A Review on Greening and Glycoalkaloids in Potato Tubers: Potential Solutions

Greening is an undesirable trait that develops in potatoes upon light exposure. This condition lowers market value, increases tuber waste in retail stores, and consequently influences the price of product in the long run. When potatoes are subjected to artificial light, the amyloplast converts into chloroplast. Although the development of total glycoalkaloids (TGA) is independent of light, the greening induced by exposure of potato to artificial light is an indication of probable TGA acceleration, which could be present in a low amount initially. Several research studies on optimum postharvest factors (temperature, lighting condition, relative humidity, pretreatment, storage air composition, and packaging) have been carried out to avoid greening and TGA development. This current review highlights major postharvest factors and summarizes past research regarding cause of greening and TGA development in potatoes in retail stores. Additionally, it also portrays the potential solutions that could help mitigate this problem, ultimately reducing wastage and achieving food security.

Effect of xanthan gum and carboxymethyl cellulose on structure, functional and sensorial properties of yam balls

Yam and its products can be modified during processing to reduce losses and ensure food security in the developing world. Xanthan gum (XG) and carboxymethyl cellulose (CMC) were added at different concentrations to yam balls and their effect on the structural, functional, and sensory properties of frozen yam balls were investigated in this study. Freeze-thaw stability and oil absorption capacity of yam ball mix were determined. Sensory evaluation and instrumental texture profile analysis (TPA) were done on samples of deep-fried yam balls using TA-XT Texture Analyser. Yam balls mixture containing XG and CMC had significantly (p < 0.05) lower oil uptake and water migration rates of 0.19 g/g and 4.10% as compared to control products 0.25 g/g and 11.05% respectively. Deep-fried yam balls samples containing 1 g of both XG and CMC obtained higher scores for their sensory attributes, while samples containing 2 g of both hydrocolloids were the chewiest. The findings suggest that the addition of hydrocolloids; XG and CMC enhances the freeze-thaw stability and reduces the oil absorption potential of the yam balls mix, and improve the sensory and texture properties of deep-fried yam balls.

Impact of ultrasonication applications on color profile of foods

Food color is a feature that provides preliminary information about their preference or consumption. There are dominant pigments that determine the color of each food; the most important pigments are anthocyanins (red-purple color), chlorophylls (green color), carotenoids (yellow-orange color), and betalains (red color). These pigments can be easily affected by temperature, light, oxygen, or pH, thereby altering their properties. Therefore, while processing, it is necessary to prevent the deterioration of these pigments to the maximum possible extent. Ultrasonication, which is one of the emerging non-thermal methods, has multidimensional applications in the food industry. The present review collates information on various aspects of ultrasonication technology, its mechanism of action, influencing factors, and the competence of different ultrasonication applications (drying, irradiation, extraction, pasteurization, cooking, tempering, etc.) in preserving the color of food. It was concluded that ultrasonication treatments provide low-temperature processing at a short time, which positively influences the color properties. However, selecting optimum ultrasonic processing conditions (frequency, power, time, etc.) is crucial for each food to obtain the best color. The key challenges and limitations of the technique and possible future applications are also covered in the paper, serving as a touchstone for further research in this area.

Mitigation of Acrylamide in Potato Chips by Pre-drying and Pulsed Electric Field Treatment

The object of this work was to study the effects of preliminary vacuum drying (VD), pulsed electric field (PEF) treatment, frying temperature on color, oil uptake, and acrylamide (AA) content in fried potato chips. The results of this study indicated that an increase of frying temperature from 120 to 180°C led to a decrease of frying time of around 70% for untreated and PEF pre-treated samples. The color value of L* and a* decreased with the increase of frying temperature, and those values of the sample pre-treated by PEF were significantly higher compared to those obtained from untreated samples. The PEF pre-treatment promoted the reduction of oil content of fried samples by up to 17.6, 14.2, and 16% compared with untreated samples at the frying temperatures of 120, 150, and 180°C, respectively. Higher efficiency was observed by applying the preliminary VD in the case of the frying temperature of 150°C. Furthermore, it was revealed that PEF pre-treatment and preliminary VD application lead to a synergetic effect on the reduction of AA content in potato chips. For example, with the initial moisture ratio of 0.5, pre-dried by VD and pre-treated by PEF, the AA content was noticeably decreased from 2,220 to 311 μg/kg compared to untreated and undehydrated samples at the frying temperature of 150°C. Our findings provide reference for a new pre-treatment to mitigate AA formation and to improve the quality of potato chips.

Effects of Konjac Glucomannan on Oil Absorption and Safety Hazard Factor Formation of Fried Battered Fish Nuggets

The purpose of this study was to investigate the effects of konjac glucomannan (KGM) on oil absorption and the formation of safety hazard factors in fried battered fish nuggets by measuring advanced glycation end products (AGEs) and acrylamide contents. Other physicochemical properties were determined to explore the reason for oil absorption and formation of safety hazard factors. The acrylamide was found mainly in the crust. The addition of 0.8% KGM could significantly reduce the acrylamide content (p < 0.05). For the battered sample, the AGEs content was far lower than the unbattered. The addition of 0.8% KGM could significantly reduce the AGEs content in the inner layer (p < 0.05). The microstructure showed that the sample with 0.8% KGM had the most compact crust. The compact crust reduced oil and malondialdehyde contents. Combined with the other indicators, the inhibitory effect of 0.8% KGM on acrylamide was closely related with the decreased extent of oil oxidation and Maillard reaction in the samples with 0.8% KGM. The inhibitory effect of 0.8% KGM on AGEs might originate from its lower oil content.

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.

Insight into the effect of fatty acid composition on the texture of French fries

BACKGROUND

Several researchers have reported that the texture of fries is affected by the fatty acid composition of oil, although the mechanism of this effect is not clear. In this regard, fries were fried in refined rapeseed oil and fully hydrogenated rapeseed oil with diverse proportions (0%, 20%, 40%, 60%, 80% and 100%) and were analyzed based on the content of moisture and oil, texture, thermal properties, crystalline properties and microstructure.

RESULTS

The outcomes presented that fries fried in fully hydrogenated oil had less oil absorption and moisture loss than those fried in refined oil. The results from the texture analyzer, differential scanning calorimetry and X-ray diffraction showed that hardness, enthalpy and relative crystallinity increased with an increase in the proportion of fully hydrogenated oil. However, the peaks of starch-lipid complexes were hardly observed during frying. Furthermore, scanning electron microscopy results displayed that some physically trapped fat was observed in fries fried in mixed hydrogenated oil. Stereomicroscope images showed that the crust thickness of the fries increased slightly with an increase in the proportion of fully hydrogenated oil.

CONCLUSION

Overall, the upsurge in crust thickness and oil crystals was responsible for an increase in the hardness of the fries. This indicated that the texture of fries can be manipulated by altering the fatty acid composition of the oil. © 2021 Society of Chemical Industry.

High-Pressure Processing on Whole and Peeled Potatoes: Influence on Polyphenol Oxidase, Antioxidants, and Glycaemic Indices

Polyphenol oxidase (PPO) inactivation in five whole and peeled Irish potato cultivars was investigated using high-pressure processing (HPP) at 400 MPa and 600 MPa for 3 min. PPO activity was significantly lower in most of the HPP-treated samples, while the highest PPO inactivation was observed after HPP at 600 MPa. No significant (p > 0.05) changes were observed on the total phenolic content and antioxidant activity of all the HPP-treated potatoes. Regarding individual phenolic acids, chlorogenic acid was decreased significantly (p < 0.05) in all studied varieties with a concomitant increase (p < 0.05) in caffeic and quinic acid. Similarly, ferulic acid was also increased (p < 0.05) in all studied varieties after the HPP treatment, while there was a variation in rutin and 4-coumaric acid levels depending on the cultivar and the sample type. Anthocyanins in the coloured whole potato varieties (i.e., Kerr’s Pink and Rooster), tentatively identified as pelargonidin-O-ferulorylrutinoside-O-hexoside and pelargonidin-O-rutinoside-O-hexoside, also exhibited significantly (p < 0.05) higher levels in the HPP-treated samples as opposed to those untreated. Glycaemic indices of the potatoes treated with HPP did not differ with the corresponding untreated cultivars.

Ultrasound, infrared and its assisted technology, a promising tool in physical food processing: A review of recent developments

Traditional food processing techniques can no longer meet the ever increasing demand for high quality food across the globe due to its low process efficiency, high energy consumption and low product yield. This review article is focused on the mechanism and application of Infrared (IR) and ultrasound (US) technologies in physical processing of food. We herein present the individual use of IR and US (both mono-frequency and multi-frequency levels) as well as IR and US supported with other thermal and non-thermal technologies to improve their food processing performance. IR and US are recent thermal and non-thermal technologies which have now been successfully used in food industries to solve the demerits of conventional processing technologies. These environmentally-friendly technologies are characterized by low energy consumption, reduced processing time, high mass-transfer rates, better nutrient retention, better product quality, less mechanical damage and improved shelf life. This work could be, with no doubt, useful to the scientific world and food industries by providing insights on recent advances in the use of US and IR technology, which can be applied to improve food processing technologies for better quality and safer products.

Effects of preliminary treatment by ultrasonic and convective air drying on the properties and oil absorption of potato chips

The initial water content was closely related to the oil absorption and properties of fried food. The effects of convective air drying (D) and ultrasound combined convective air drying (UD) pretreatment on the properties and oil absorption of potato chips have been investigated. The oil contents were 48.48 ± 1.42% and 39.78 ± 3.08% for control samples (without D and UD pretreatment) and ultrasound treated samples (without D pretreatment). When the mass loss of samples was reached the proportion of quality to without drying samples quality 80%, 50%, and 20%, the oil contents of D pretreated samples decreased by 12.67%, 28.24% and 62.07%, respectively, and the oil contents of UD pretreated samples decreased by 7.42%, 24.10% and 51.76% (compared to the ultrasound pretreated samples ), respectively. By applying ultrasound before frying, more cracks and pores were exhibited of fried potato chips. After drying process, potato chips exhibited less disruption of cell structure and less deformation of cell irregular. The hardness of the D and UD pretreated potato chips increased with the extension of drying. The FTIR analysis stated the formation of amylose-lipid complexes. This research could contribute to providing evidence for the development and application of the pretreatment strategies.

High-Pressure Processing and Ultrasonication of Minimally Processed Potatoes: Effect on the Colour, Microbial Counts, and Bioactive Compounds

HPP at 600 MPa alone, and in combination with US at 20 kHz (200 W), was applied to minimally processed potatoes of two commonly grown cultivars in Ireland. Changes in colour and microbial load (Enterobacteriaceae, total aerobic count, Salmonella, yeasts, and moulds) were monitored in vacuum-packaged potatoes during 14 days of storage at 4 °C. HPP and HPP/US significantly (p < 0.05) affected the colour parameters a*, b*, L*, and ΔE of minimally processed potatoes compared to the controls. Microbial growth was delayed in most of the treated samples with respect to those untreated (controls), while HPP completely inactivated Enterobacteriaceae in both cultivars. Total phenolic content and antioxidant activities were not altered in the treated samples of both varieties when compared to the controls. The levels of chlorogenic acid, ferulic acid, and caffeic acid were decreased after both treatments, with a significant (p < 0.05) increase in quinic acid in the treated samples as opposed to those untreated. A significant (p < 0.05) decrease in the levels of glycoalkaloids, namely α-chaconine and α-solanine, in HPP- and HPP/US-treated potatoes was also observed. These findings suggest that HPP and US can extend the shelf-life of minimally processed potatoes with a negligible impact on their antioxidant activity and phenolic content.

Characteristics of French Fries and Potato Chips in Aspect of Acrylamide Content—Methods of Reducing the Toxic Compound Content in Ready Potato Snacks

The reduction of toxic acrylamide content in potato snacks, i.e., French fries and potato chips, is necessary due to the adverse effects of this compound on the human body. Therefore, in the presented review paper, a detailed characterization of French fries and chips in terms of AA content and their organoleptic quality is included. Detailed information was also collected on the raw material and technological factors that affect the formation of acrylamide content, including methods and techniques affecting the reduction of the amount of this compound in potato snacks. The obligation to control the level of acrylamide in various food products (including fried potato snacks with a higher content of this compound), introduced in 2018, has mobilized manufacturers to seek solutions, while scientists conduct further intensive research on the possibility of reducing the level of AA or even eliminating its presence from products. Therefore, it is necessary to conduct such activities, especially, because potato French fries and potato chips are willingly consumed by younger and younger consumers.

Chemical constituents of fresh-cut potato as affected by cultivar, age, storage, and cooking

Certain changes in phenolics and sugars can occur during the storage of potatoes, where particularly amounts of sugars represent the critical factor as they are involved in potentially harmful acrylamide (AA) formation during frying. This research investigates the impact of cultivars (Birgit and Lady Claire), tuber's age (1, 5, and 9 months), and storage duration (1, 5, and 8 days at 10 °C) on the content of phenolics and sugars in raw, boiled, and fried fresh-cut potato (FCP). The influence of these factors on the formation of AA in fried FCP was also assessed. Significant differences in phenolics and sugars were observed between cultivars (cv. Birgit contained 5.77 mg of phenolics 100 g^-1 of dry weight (DW) and 1.75 g of sugars 100 g^-1 DW, while cv. Lady Claire contained 10.13 mg of phenolics 100 g^-1 DW and 0.65 g of sugars 100 g^-1 DW). The content of phenolics significantly decreased, while sugars increased during tubers' aging. FCP storage time had no significant influence on the content of phenolics and sugars. The phenolics and sugars were the highest in the raw samples and the lowest in the boiled ones. Although the AA level in fried samples was significantly influenced by cultivar (Birgit > Lady Claire) and it increased with FCP storage time, it was below European Food Safety Authority (EFSA) regulation's approved maximum value (750 µg kg^-1 FW) in both cultivars. Therefore, cvs. Birgit and Lady Claire could be considered as promising FCP cultivars and for frying purposes. PRACTICAL APPLICATION: The results of this research reveal that quantitative changes of chemical constituents occurring during storage and cooking of fresh-cut slices of potato cultivars Birgit and Lady Claire are not a concern. This is of particular importance to fresh-cut producers and customers. Phenolics were reduced during storage, but they were still present in all cooked samples independently of the cooking method. The analysis of sugars showed that tubers as old as 9 months could be used for fresh-cut potato processing, providing safe frying without critical levels of acrylamide.

Relevance of genipin networking on rheological, physical, and mechanical properties of starch-based formulations

The small amount of proteins in starch-rich food industry byproducts can be an advantage to crosslink with genipin and tailor the performance of biobased films. In this work, genipin was combined with non- purified starch recovered from industrial potato washing slurries and used for films production. Starch recovered from potato washing slurries contained 0.75% protein, 2 times higher than starch directly obtained from potato and 6 times higher than the commercial one. Starch protein-genipin networks were formed with 0.05% and 0.10% genipin, gelatinized at 75 °C and 95 °C in presence of 30% glycerol. Bluish colored films were obtained in all conditions, with the higher surface roughness (Ra, 1.22 μm), stretchability (elongation, 31%), and hydrophobicity (water contact angle, 127°) for 0.10% genipin and starch gelatinized at 75 °C. Therefore, starch-rich byproducts, when combined with genipin, are promising for surpassing the starch-based films hydrophilicity and mechanical fragilities while providing light barrier properties.

Recent advances in physical fields-based frying techniques for enhanced efficiency and quality attributes

Frying is one of the most common units in food processing and catering worldwide, which involves simultaneous physicochemical and structural changes. However, the problems of traditional frying technology, such as low thermal utilization and poor processing efficiency, have been gradually exposed to industrial production. In this paper, strategies of applying physical fields, such as pressure field, electromagnetic field, and acoustic field in frying technology separately or synergistically with improved efficiency and quality attributes are reviewed. The role of physical fields in the frying process was discussed with modifications in heat and mass transfer and porous structures. The effects of physical fields and their processing parameters on moisture loss kinetics, oil uptake, texture, color, and nutrients retention of fried food are introduced, respectively. Recent advances in multi-physical field-based frying techniques were recommended with synergistic benefits. Furthermore, the trends and challenges that could further develop the multi-physical field-based frying techniques are proposed, showing further commercial prospects for the purpose. The application of physical fields has brought new inspiration to the exploitation of efficient and high-qualified frying technologies, while higher technical levels and economic costs need to be taken into consideration. HighlightsThe role of physical fields in pretreatments and frying process were reviewed.The mechanism of physics fields on frying efficiency and quality was summarized.The physicochemical and microstructure changes by physics fields were discussed.The synergy of physical fields in frying technology were outlined.The trends for further multi-physical field-based frying techniques were proposed.

Effects of ultrasound treatment on the starch properties and oil absorption of potato chips

As a non-thermal processing method, the ultrasound treatment prior to the frying process has been demonstrated with great potential in reducing the oil absorption of fried food. This research aimed to evaluate the effect of ultrasound pretreatment on starch properties, water status, pore characteristics, and the oil absorption of potato slices. Ultrasound probe set with two power (360 W and 600 W) at the frequency of 20 kHz for 60 min was applied to perform the pretreatments. The results showed that ultrasound pretreatment led to the surface erosion of starch granules and higher power made the structure of starch disorganized. Moreover, the fraction of bound water and immobilized water were changed after ultrasonic pretreatment. Pores with the minor diameters (0.4-3 μm and 7-12 μm) were formed after ultrasound pretreatment. The penetrated surface oil (PSO) content, and structure oil (STO) content were reduced by 27.31% and 22.25% respectively with lower power ultrasound pretreatment. As the ultrasound power increased, the surface oil (SO) content and PSO content increased by 25.34% and 12.89% respectively, while STO content decreased by 38.05%. By using ultrasonic prior to frying, the quality of potato chips has been greatly improved.

Effect of excessive nitrogen on levels of amino acids and sugars, and differential response to post-harvest cold storage in potato (Solanum tuberosum L.) tubers

Nitrogen (N) is an important nutrient for increased potato tuber yield. However, excessive N can decrease tuber quality. Furthermore, the impact of optimal and higher N levels of potato tuber metabolic profile at harvest and cold storage remains unclear. This study aimed to investigate the metabolic profiling of free amino acids and sugars in potato tubers affected by different nitrogen levels (optimal, ON; and excessive, EN) at harvest (AH) and cold storage (CS) (~4 °C, 4 weeks) through untargeted GC-TOF-MS, and targeted UHPLC-QqQ-MS. Carbohydrate content and vacuolar invertase activity (IV) were determined. Principal component analysis of metabolite data indicated a distinct separation between ON and EN treatments at harvest and cold storage. Multivariate data analysis revealed that sucrose, reducing sugars, and free asparagine were the most altered metabolites (VIP > 1 and P < 0.05), which were involved in starch and sucrose metabolism, and alanine, aspartate and glutamate metabolism. At harvest, the absolute contents of various free amino acids including asparagine were higher (by 1.3-1.5 fold) in the EN treatment than ON treatment, and this difference was maintained at 4-week cold storage. Under the EN treatment, tuber maturity was reduced, and sucrose accumulation was increased at harvest, while IV was increased after cold storage, reducing sugar also accumulated. These results highlighted the negative effects of EN on free amino acid and sugars metabolism in the post-harvest tubers and provided useful information for understanding the underpinning physiological mechanisms.

Comparison between synthetic and rosemary-based antioxidants for the deep frying of French fries in refined soybean oils evaluated by chemical and non-destructive rapid methods

Using natural antioxidants instead of synthetics ones has been the tendency for retarding the oil deterioration during repeated deep frying process. Concerning this, the comparison between synthetic tertiarybutyl hydroquinone (TBHQ) and rosemary-based antioxidants in frying French fries was hereby evaluated. The quality and stability of frying oils with rosemary-based antioxidants showed higher efficiency than TBHQ regarding oxidation parameters (i.e., chemical indices, sensory, etc.), where rosmarinic acid (RA) was the most effective, followed by rosemary extracts (RE) and carnosic acid (CA). LF-NMR results were highly correlated (R² = 0.909-0.998) to the change in physicochemical properties tested, where RA could effectively regulate the relaxation spectrum (T₂) change and decrease single component relaxation time (T_2W). The PCA graph of NIRS also revealed the dynamic change of antioxidant effectiveness in accordance with that obtained by chemical methods. Hence, both LF-NMR and NIRS can be expected as rapid and efficient methods for future monitoring the frying process.

Fresh-cut potato quality and sensory: Effect of cultivar, age, processing, and cooking during storage

This work examined the influence of cultivar, tubers' age, antibrowning agent, package atmosphere, and storage time on fresh-cut potatoes' (FCPs) physical, chemical, and sensory properties. Potato slices of cv. Birgit and Lady Claire tubers sampled during the first, fifth, and ninth months of storage were dipped in solutions of (1) sodium chloride (1%) and (2) sodium ascorbate (2%), and stored for 8 days in (1) vacuum and (2) active modified atmosphere (MAP) (10.0% CO₂ , 3.0% O₂ , and 87.0% N₂ ) at 10 °C. During storage, O₂ and CO₂ content (%) within packages was measured and samples were analyzed for weight loss, total solids (TS) and soluble solids (SS), pH, color, texture, and sensory properties of raw, boiled, fried, and baked FCP. Results showed that 9 months' aging had a significant impact on almost all investigated FCP properties, but differences among first, fifth, and ninth months were numerically feeble for some parameters in raw samples: TS changed from 22.14% to 20.98%, SS 5.53% to 6.93%, pH 6.02 to 5.98, L^* 70.10 to 68.87, C^* 35.75 to 36.70, H° 89.29 to 88.15, and firmness 7.25 to 8.13N. Furthermore, 9 months of aging had no significant influence on the characteristic odor of raw, boiled, fried, and baked FCP and characteristic taste of fried and baked FCP, whereas boiled FCP characteristic taste remained unchanged for 5 months of aging. Fried FCP was better sensory evaluated than baked ones, cv. Birgit was more suitable for the FCP production compared to cv. Lady Claire as well as vacuum packaging and sodium ascorbate better preserved samples quality and sensory than sodium chloride and MAP. PRACTICAL APPLICATION: This study could be helpful to fresh-cut potato (FCP) producers because results indicate that for FCP processing, along with the selection of cultivar, antibrowning agent, and packaging type, tubers' age also requires attention. A further contribution of this research is related to the adequate way of FCP cooking, where frying shows the best results according to the quality and sensory assessment.

Effect of the wheat starch/wheat protein ratio in a batter on fat absorption and quality attributes of fried battered and breaded fish nuggets

Battered and breaded fish nuggets (BBFNs) were prepared by treating fish with a batter composed of wheat starch (WS) and wheat protein (WP) blends (at the ratios of 15:1, 13:1, 11:1, 9:1, and 7:1, w/w), frying at 170 °C (40 s) followed by 190 °C (30 s). Fried BBFNs were evaluated for moisture and fat contents, color, shrinkage, acrylamide content, and fat distribution. Results showed that moisture content and brightness (L^* value from colorimetry) increased with a decrease of WS/WP ratio to 11:1 w/w, then decreased as WS/WP ratio further decreased, while fat content, fat distribution level, and shrinkage of fried BBFNs presented opposite results. However, there was a slight influence of WS/WP ratio on yellowness (b^* value), redness (a^* value), and acrylamide content of fried BBFNs. Among WS/WP ratios, fried BBFNs with 11:1 w/w have the highest moisture content (16.43%) and the lowest fat content (23.39%), fat distribution level, shrinkage (10.72%), and acrylamide content (57 mg/kg), while a crust with golden-yellow color was observed. This study demonstrates that moisture evaporation and fat absorption were significantly influenced by WS/WP ratio in the batter (P < 0.05), with the most effective results in quality attributes improvement of fried BBFNs. PRACTICAL APPLICATION: This study clearly showed that the fat content and quality attributes of fried BBFNs were significantly affected by WS/WP ratio in the batter (P < 0.05). The inhibition of fat absorption and improvement of shrinkage and color in fried BBFNs was the most effective for a 11:1 w/w WS/WP ratio.

Green ultrasound-assisted extraction of chlorogenic acids from sweet potato peels and sonochemical hydrolysis of caffeoylquinic acids derivatives

Sweet potato peels are rich in chlorogenic acids. In this work, we applied ultrasound technology to extract the main compounds from sweet potato peel and used multivariate analysis and principal component analysis (PCA) to evaluate the effects of different extraction conditions on the extraction of chlorogenic acids. The extraction was studied varying ultrasonic power density (20, 35 and 50 W/L) and processing time (5, 10, 20 and 40 min) using an ultrasonic bath operating at 25 kHz. The chemical analysis was carried out by UPLC-qTOF-MS, and the results were evaluated by PCA and PLS-DA chemometric analysis. Results show that both ultrasonic power density and processing time influences in the extraction of different chlorogenic acid, and that different extraction conditions can be used to selectively extract specific caffeoylquinic acids and feruloylquinic acids in higher amounts. Ultrasound promoted the hydrolysis of tricaffeoylquinic acid when subjected to ultrasonic waves (20-50 W/L), and of 3,4-caffeyolquinic acid at high ultrasonic power density (50 W/L).