Effect of Convective and Vacuum–Microwave Drying on the Bioactive Compounds, Color, and Antioxidant Capacity of Sour Cherries

Effects of air-impingement jet drying on drying kinetics, color, polyphenol compounds, and antioxidant activities of Boletus aereus slices

The aim of the study is to interpret the effects of air-impingement jet drying (AIJD) on drying kinetics, color, polyphenols, and antioxidation ability of Boletus aereus slices. Page model was most suitable for expressing and predicting AIJD curves of B. aereus slices. The moisture-effective diffusion coefficient of AIJD ranged from 7.8876 × 10^-10 to 2.1426 × 10^-9 m² /s, and AIJD also showed high efficiency due to its low activation energy (45.37 kJ/mol). AIJD is better for B. aereus slices than hot air drying (HAD) in accelerating the drying rate (DR) and shortening drying time, and maintaining color. p-hydroxybenzoic acid, protocatechuic acid, and rutin were identified in B. aereus slices by ultra high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS). Total polyphenols, flavanone, phenolic acids, and antioxidant activities were significantly lower in dried B. aereus slices than those in fresh B. aereus slices. In AIJD, drying temperature had the greatest effect on the quality of B. aereus slices, and AIJD at 50 °C is the optimum drying condition for B. aereus slices. PRACTICAL APPLICATION: Boletus aereus occurs in many countries all over the world. In this paper, the effect of AIJD on color, polyphenols, and antioxidation ability in B. aereus slices and its drying kinetics were studied. AIJD is an efficient drying method for B. aereus by decreasing its drying time, increasing DR, and protecting the color of B. aereus. These findings have provided important reference basis for people to have a better understanding of AIJD method, which was used to dry B. aereus. This study also provides a new technique for drying B. aereus, which could improve dry efficiency and reduce drying cost.

Microwave and Ultrasound Pre-Treatments for Drying of the "Rocha" Pear: Impact on Phytochemical Parameters, Color Changes and Drying Kinetics

The objective of this research was to evaluate the effect of drying temperature and innovative pre-treatments (i.e., microwave and ultrasound) on “Rocha” pear drying behavior and quality characteristics, such as color, total phenolic content and antioxidant activity. Experiments were carried out with pear slabs subjected to microwaves (2450 MHz, 539 W, 4 min, microwave oven) and ultrasounds (35 kHz, 10 min, in an ultrasonic bath) as well as control samples. The drying process was conducted in a tray dryer at three different temperatures (50, 55 and 60 °C) and a fixed air velocity of 0.75 m/s. Microwave technology resulted in a higher quality deterioration in dried pear samples compared to those of controls and ultrasound pre-treated samples. The combined application of ultrasound pre-treatment and the higher drying temperature of 60 °C was characterized by the lowest color changes (ΔE = 3.86 ± 0.23) and higher preservation of nutritional parameters (total phenolic content, TPC = 345.60 ± 8.99; and antioxidant activity, EC₅₀ = 8.80 ± 0.34). The drying characteristics of pear fruits were also analyzed by taking into account empirical models, with the Page model presenting the best prediction of the drying behavior. In conclusion, ultrasound application is a promising technology to obtain healthy/nutritious dried “Rocha” pear snacks as dietary sources for consumers.

Utilization of Cumbeba (Tacinga inamoena) Residue: Drying Kinetics and Effect of Process Conditions on Antioxidant Bioactive Compounds

The residue generated from the processing of Tacinga inamoena (cumbeba) fruit pulp represents a large amount of material that is discarded without proper application. Despite that, it is a raw material that is source of ascorbic acid, carotenoids and phenolic compounds, which are valued in nutraceutical diets for allegedly combating free radicals generated in metabolism. This research paper presents a study focused on the mathematical modeling of drying kinetics and the effect of the process on the level of bioactive of cumbeba residue. The experiments of cumbeba residue drying (untreated or whole residue (WR), crushed residue (CR) and residue in the form of foam (FR)) were carried out in a fixed-bed dryer at four air temperatures (50, 60, 70 and 80 °C). Effective water diffusivity (Deff) was determined by the inverse method and its dependence on temperature was described by an Arrhenius-type equation. It was observed that, regardless of the type of pretreatment, the increase in air temperature resulted in higher rate of water removal. The Midilli model showed better simulation of cumbeba residue drying kinetics than the other models tested within the experimental temperature range studied. Effective water diffusivity (Deff) ranged from 6.4890 to 11.1900 × 10-6 m2/s, 2.9285 to 12.754 × 10-9 m2/s and 1.5393 × 10-8 to 12.4270 × 10-6 m2/s with activation energy of 22.3078, 46.7115 and 58.0736 kJ/mol within the temperature range of 50-80 °C obtained for the whole cumbeba, crushed cumbeba and cumbeba residue in the form of foam, respectively. In relation to bioactive compounds, it was observed that for a fixed temperature the whole residue had higher retention of bioactive compounds, especially phenolic compounds, whereas the crushed residue and the residue in the form of foam had intermediate and lower levels, respectively. This study provides evidence that cumbeba residue in its whole form can be used for the recovery of natural antioxidant bioactive compounds, mainly phenolic compounds, with the possibility of application in the food and pharmaceutical industries.

The Quality of Infrared Rotary Dried Terebinth (Pistacia atlantica L.)-Optimization and Prediction Approach Using Response Surface Methodology

Most agricultural products are harvested with a moisture content that is not suitable for storage. Therefore, the products are subjected to a drying process to prevent spoilage. This study evaluates an infrared rotary dryer (IRRD) with three levels of infrared power (250, 500, and 750 W) and three levels of rotation speed (5, 10, and 15 rpm) to dry terebinth. Response surface methodology (RSM) was used to illustrate and optimize the interaction between the independent variables (infrared power and rotation speed) and the response variables (drying time, moisture diffusivity, shrinkage, color change, rehydration rate, total phenolic content, and antioxidant activity). As infrared power and rotation speed increased, drying time, rehydration rate, antioxidant activity, and total phenolic content decreased, while the other parameters were increased. According to the results, the optimum drying conditions of terebinth were determined in the IRRD at an infrared power of 250 W and drum rotation speed of 5 rpm. The optimum values of the response variables were 49.5 min for drying time, 8.27 × 10⁻⁹ m²/s for effective moisture diffusivity, 2.26 for lightness, 21.60 for total color changes, 34.75% for shrinkage, 2.4 for rehydration rate, 124.76 mg GAE/g d.m. for total phenolic content and 81% for antioxidant activity.

Revisiting the contribution of ATR-FTIR spectroscopy to characterize plant cell wall polysaccharides

The contribution of ATR-FTIR spectroscopy to study cell wall polysaccharides (CWPs) was carefully investigated. The region 1800-800 cm^-1 was exploited using principal component analysis and hierarchical clustering on a large range of different powders of CWPs based on their precise chemical characterization. Relevant wavenumbers were highlighted for each CWP: 1035 cm^-1 was attributed to xylose-containing hemicelluloses, 1065 and 807 cm^-1 to mannose-containing hemicelluloses, 988 cm^-1 to cellulose, 1740 and 1600 cm^-1 to homogalacturonans according to the degree of methylation. Some band positions were affected by macromolecular arrangements (especially hemicellulose-cellulose interactions). However, as arabinan and galactan did not reveal distinctive absorption bands, ATR-FTIR spectroscopy did not allow the discrimination of cell walls differing by the abundance of these polysaccharides, e.g., those extracted from apple and beet. Therefore, the application of ATR-FTIR could remain sometimes limited due to the complexity of overlapping spectra bands and vibrational coupling from the large diversity of CWP chemical bonds.

Comparison of Microwave Short Time and Oven Heating Pretreatment on Crystallization of Raisins

Crystalline material can develop on the surface of raisins during storage and transport, affecting the final acceptability of the product. In this work, a mild thermal pretreatment was applied to raisins to melt the pre-existing crystals and the effect of such thermal treatments on the development of crystals over a storage period was investigated. The raisins selected for this study were of the Thompson seedless variety from one Chilean company. The thermal pretreatment of raisins at 50 °C and 70 °C for 20 min in an oven and microwave (800 W) irradiation for 15 s resulted in a reduction in the percentage of crystallized raisins (w/w) from more than 50% in the control samples to less than 10% after 35 days of storage at 15 and 25 °C in a 57% relative humidity environment. The results showed that some textural parameters, such as cohesiveness and chewiness, were not affected by thermal treatment and were independent of storage temperature.

Evaluating drying feature differences between ginger slices and splits during microwave-vacuum drying by hyperspectral imaging technique

This study aimed to investigate the difference between ginger slices (vertically cut) and splits (horizontally cut) during microwave-vacuum drying (MVD) procedures. MVD ginger slices showed a higher shrinkage rate and a higher hardness value, with a more porous structure of the surface layer. MVD ginger splits had higher rehydration rates at the first 15 min of the rehydration. Nine optimal wavelengths were selected by regression coefficients (RC) from the partial least squares regression (PLSR) model based on the raw data. A simplified PLSR model based on optimal wavelengths showed a good performance with a coefficient of determination in prediction (Rp2) of 0.973 and a root mean square error in prediction (RMSEP) of 4.63%. Texture features of grey level co-occurrence matrix (GLCM) of moisture prediction maps demonstrated a more uniform moisture distribution in MVD ginger slices than that in splits in the original geometry.

Effects of Different Drying Methods on the Retention of Bioactive Compounds, On-Line Antioxidant Capacity and Color of the Novel Snack from Red-Fleshed Apples

The aim of this study was to determine the effect of different drying methods: convective (at 50, 60, 70 °C), vacuum-microwave (at 120, 240, 360, 480 W and 360 W with reduction to 120 W) and hybrid (convective pre-drying at 50, 60, 70 °C followed by vacuum-microwave drying at 120 W) on the quality parameters of novel red-fleshed apple fruit snacks (RFAs), such as phenolics, on-line antioxidant capacity, water activity and color. Drying kinetics, including a temperature profile of dried material, and modified Page model were determined. Freeze-drying was used as a control method. The highest content of bioactive compounds in the samples was retained following freeze-drying, then hybrid, vacuum-microwave and finally convection drying. The antioxidant capacity measured by on-line 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), identified anthocyanins, flavan-3-ols and phenolic acid as the main compounds responsible for this activity. Unfavorable changes in color, formation of hydroxymethylfurfural (HMF) and degradation of polyphenolics were noted along with increasing drying temperature and magnetron power. The red-fleshed apple snacks are a promising high-quality dehydrated food product belonging to functional foods category.

Effect of blanching pretreatment and microwave-vacuum drying on drying kinetics and physicochemical properties of purple-fleshed sweet potato

In this study, drying kinetics and quality of purple-fleshed sweet potato (PFSP) subjected to microwave-vacuum drying were investigated. The effects of hot water and steam blanching pretreatment on physicochemical characteristics of the dried products were also considered. The samples were dehydrated in a custom-made microwave-vacuum system at different power levels including 450, 600 and 850 W. Hot air drying at 70 °C was also conducted for comparison. The results showed that drying time of PFSP under microwave-vacuum conditions ranged from 6 to 12 min, significantly reduced as compared to that of hot air drying (600 min). The improvement of drying rate was also evidenced by increased effective moisture diffusivity (2.22 × 10^-7-4.05 × 10^-7 m²/s) of the samples. Drying kinetics of PFSP was best fitted by Page and logarithmic model with R² ranging from 0.991 to 0.998, and RMSE from 0.016 to 0.030. PFSP dried under microwave-vacuum condition had lower water absorption index and swelling capacity than hot air drying. Color, antioxidant activity and total phenolic content of dried PFSP were also improved under microwave-vacuum drying. The effects of blanching pretreatment on quality of dried PFSP were more dominant in hot air than microwave-vacuum dried samples.

Comparison of Traditional and Novel Drying Techniques and Its Effect on Quality of Fruits, Vegetables and Aromatic Herbs

Drying is known as the best method to preserve fruits, vegetables, and herbs, decreasing not only the raw material volume but also its weight. This results in cheaper transportation and increments the product shelf life, limiting the food waste. Drying involves the application of energy in order to vaporize and mobilize the moisture content within the porous products. During this process, the heat and mass transfer occurs simultaneously. The quality of dehydrated fruits, vegetables, and aromatic herbs is a key problem closely related to the development and optimization of novel drying techniques. This review reports the weaknesses of common drying methods applied for fruits, vegetables, and aromatic herbs and the possible options to improve the quality of dried products using different drying techniques or their combination. The quality parameters under study include color, bulk density, porosity, shrinkage, phytochemicals, antioxidant capacity, sugars, proteins, volatile compounds, and sensory attributes. In general, drying leads to reduction in all studied parameters. However, the behavior of each plant material is different. On the whole, the optimal drying technique is different for each of the materials studied and specific conditions must be recommended after a proper evaluation of the drying protocols. However, a novel or combined technique must assure a high quality of dried products. Furthermore, the term quality must englobe the energy efficiency and the environmental impact leading to production of sustainable dried products.

Application of sodium chloride and quince seed gum pretreatments to prevent enzymatic browning, loss of texture and antioxidant activity of freeze dried pear slices

ABSTRACT

In the study the effect of sodium chloride and quince seed gum solutions as immersion pretreatment to prevent enzymatic browning reaction in pear slices before freeze drying was evaluated. Four levels of gum concentrations (0%, 0.25%, 0.5% and 1%) and three concentrations of salt (0%, 0.25% and 0.5%) were used. Subsequently, freeze drying method was used to dry the pear slices and the qualitative, structural and sensory characteristics of dried pear slices were investigated. The moisture content of the dried pear slices decreased significantly with increasing sodium chloride concentration, while increasing the concentration of the gum significantly increased the moisture content (P < 0.05). Use of both immersion pretreatments were effective in maintaining the antioxidant activity and reducing browning index of the slides and with increasing concentration of the immersion solutions, the antioxidant activity loss decreased in the slices (P < 0.05). Electron microscopy study revealed that the microstructural changes of the drying process on the slices are very slight, although gum pre-treatment at the high levels made a layer on the surface of the pear slices which slowed down the transfer of water vapor molecules. By considering the results of qualitative, structural and sensory evaluations, using of immersion pretreatment with 0.25% gum and 0.25% salt solution to prevent enzymatic browning along with preserving the quality properties of pear slices prior to the drying process is recommended.

GRAPHIC ABSTRACT

SEM of cross section of dried pear slices after processing.

Effect of microwave-drying on the quality and antioxidant properties of Ganoderma lucidum fermented sea-buckthorn tea

Effects of microwave power on the sensory properties (taste and aroma), chemical composition (catechins, caffeine, crude protein, and amino acid), active composition (flavones, triterpene, polysaccharide, and ergosterol) and antioxidant properties (superoxide free radical and hydroxyl radical scavenging abilities, reducing power) of Ganoderma lucidum fermented sea-buckthorn tea were investigated. G. lucidum fermented sea-buckthorn tea was dehydrated using microwaves at three power settings: 125, 250, and 500. After microwave treatment, a statistically significant difference in the chemical composition, active composition and antioxidant capacity (p < 0.05) of teas dried at different power settings was found. These results indicate that 250 W microwave treatments could effectively release and activate active components, improving the antioxidant activity of fermented tea.

Clinopodium tomentosum (Kunth) Govaerts Leaf Extract Influences in vitro Cell Proliferation and Angiogenesis on Primary Cultures of Porcine Aortic Endothelial Cells

Clinopodium tomentosum (Kunth) Govaerts is an endemic species in Ecuador, where it is used as an anti-inflammatory plant to treat respiratory and digestive affections. In this work, effects of a Clinopodium tomentosum ethanolic extract (CTEE), prepared from aerial parts of the plant, were investigated on vascular endothelium functions. In particularly, angiogenesis activity was evaluated, using primary cultures of porcine aortic endothelial cells (pAECs). Cells were cultured for 24 h in the presence of CTEE different concentrations (10, 25, 50, and 100 μg/ml); no viability alterations were found in the 10-50 μg/ml range, while a slight, but significant, proliferative effect was observed at the highest dose. In addition, treatment with CTEE was able to rescue LPS-induced injury in terms of cell viability. The CTEE ability to affect angiogenesis was evaluated by scratch test analysis and by an in vitro capillary-like network assay. Treatment with 25-50 μg/ml of extract caused a significant increase in pAEC's migration and tube formation capabilities compared to untreated cells, as results from the increased master junctions' number. On the other hand, CTEE at 100 μg/ml did not induce the same effects. Quantitative PCR data demonstrated that FLK-1 mRNA expression significantly increased at a CTEE dose of 25 μg/ml. The CTEE phytochemical composition was assessed through HPLC-DAD; rosmarinic acid among phenolic acids and hesperidin among flavonoids were found as major phenolic components. Total phenolic content and total flavonoid content assays showed that flavonoids are the most abundant class of polyphenols. The CTEE antioxidant activity was also showed by means of the DPPH and ORAC assays. Results indicate that CTEE possesses an angiogenic capacity in a dose-dependent manner; this represents an initial step in elucidating the mechanism of the therapeutic use of the plant.

Comparison of different drying methods on Chinese yam: changes in physicochemical properties, bioactive components, antioxidant properties and microstructure

In the present study, we aimed to assess the effects of hot air drying (HAD), microwave drying (MD), far-infrared radiation drying (FIRD), vacuum drying (VD) and microwave vacuum drying (MVD) on the quality, bioactive components, pasting properties, antioxidant properties,in vitrodigestibility and microstructure of Chinese yam. Results showed that these drying processes greatly affected the quality of yam (p<0.05). MVD yam had a good color and its bioactive components were maintained. VD and MVD samples had the lowest setback value and breakdown value, indicating that they had a better cold paste stability and hot paste stability. In addition, MVD samples had a uniform honeycomb microscopic pore structure, and thus the rehydration rate of MVD samples was significantly higher compared with the other drying approaches. When five differently dried samples were compared by principal component analysis (PCA), the MVD samples were found to have the highest comprehensive principal component values. Therefore, based on our results, MVD was an ideal approach to dry high-quality yam.

Elucidation of the Impact of Different Drying Methods on the Key Odorants of Toona sinensis (A. Juss.) Roem. Using the Sensomics Approach

The sensomics approach was applied to both green and red Toona sinensis (TS) varieties dried with different methods (freeze drying, solar drying, and oven drying) to elucidate their influences on the key odorants in TS. Odorant screening via comparative aroma dilution analysis revealed eugenol with the highest flavor dilution factor in all six samples. Quantitation of 44 odorants via stable isotope dilution assays and semiquantitation of six compounds via an internal standard method showed (E,E)-, (E,Z)-, and (Z,Z)-di-1-propenyl disulfide, dimethyl sulfide, β-ionone, eugenol, cis- and trans-2-mercapto-3,4-dimethyl-2,3-dihydrothiophene, 2- and 3-methylbutanal, and 2-isopropyl-3-methoxypyrazine with high odor activity values (OAVs) in all samples. Differences were found for (E,Z)-2,6-nonadienal, (E,E)-, (E,Z)-, and (Z,Z)-di-1-propenyl trisulfide, 3-methylnonane-2,4-dione, and (E)-2-hexenal with clearly higher OAVs in freeze-dried (FDTS) and solar-dried TS (SDTS) compared to those in oven-dried TS (ODTS). Linalool, 2-methoxyphenol, and 4-ethylphenol (the latter two only for red TS) were obtained with high OAVs only in FDTS. In general, ODTS showed the lowest OAVs, whereas FDTS as the gentlest drying process revealed the highest OAVs for most odorants and, consequently, the highest aroma quality. However, the overall aroma of SDTS did not differ too much from that of FDTS, and thus, solar drying as a much easier and cheaper technique might be the best choice.

Design of Healthy Snack Based on Kiwifruit

Kiwifruit is an excellent source of vitamin C and other bioactive compounds, which contribute to its high antioxidant activity. However, the fruits with small size and low weight are considered waste and are unprofitable; therefore, the production of healthy kiwifruit-based dried snacks, which contain a lot of health-beneficial ingredients, could be a viable alternative for their use. The aim of this study was to develop formulations and methods to produce attractive and nutritionally valuable dried snacks based on yellow kiwifruit. Three different puree formulations (kiwifruit; fennel; and strawberry, lemon, or spinach) with or without addition of sugar were subjected to two drying methods: freeze-drying (fruit bars) and conventional hot air drying (fruit leathers). The obtained products were analysed for their content of total polyphenols (TPs), flavonoids, and vitamin C, as well as their antioxidant activity. The results showed that snacks prepared by freeze-drying (fruit bars) presented higher TP, vitamin C, and flavonoids content than those prepared by convective drying; however, the antioxidant activity did not always follow this trend. The amount of bioactive compounds depended on the formulation used for the preparation of snacks. The effect of the sugar addition seems to be strictly related to the mix used and specific bioactive compound investigated.

Bioactive, Physicochemical and Sensory Properties as Well as Microstructure of Organic Strawberry Powders Obtained by Various Drying Methods

This study compared the quality of organic strawberry powders, obtained by convective drying (CD), freeze drying (FD) and spray drying (SD) methods. In the study, such analyses were performed: the content of vitamin C and polyphenols by liquid chromatography method, antioxidant activity using ABTS+• radicals, microstructure using a scanning microscope, sensory quality by profile method and the determination of the physicochemical properties. The FD powders were characterised by the highest content of vitamin C and polyphenols, obtained values were close to fresh strawberries after conversion to the dry matter content. The content of these ingredients in CD and SD powders was lower by 55%–80% for vitamin C, and 80% for the polyphenols content. Strawberry flavour was most beneficial for the FD powders, while smoothness and homogeneity of appearance were equally rated for the FD and SD powders. Strawberry powders are a concentrate source of bioactive compounds and, therefore, the FD powders should especially be mainly used as a valuable component of high-value foods, especially functional foods, while CD and SD powders can be used to enrich food with vitamin C and as a valuable natural flavour and colouring component, replacing food additives.

Effects of drying on physical properties, phenolic compounds and antioxidant capacity of Robusta wet coffee pulp (Coffea canephora)

Wet coffee pulp (WCP), produced as waste from coffee production, is a rich source of bioactive compounds, especially caffeine and chlorogenic acid. However, it contains high moisture content, thus it is challenging for further utilization due to degradation and microbial deterioration. Dehydration is, therefore, necessary to minimize degradation and ease storage and transportation. As a waste, the common drying methods should be prioritized to be feasible for industrial application. This study aimed to determine the impact of different drying conditions of the three common drying methods including low temperature and pressure, vacuum and hot air drying on physical, phytochemical and antioxidant properties of WCP to identify the most suitable drying conditions. Browning index, moisture content, total phenolic content (TPC), flavonoids (TFC), proanthocyanidins, and chlorogenic acid as well as the antioxidant properties of the dried coffee pulp were significantly influenced by different tested conditions. Vacuum drying was found to be more suitable for drying the wet coffee pulp as compared to low temperature and pressure and hot air drying methods. Vacuum drying at 110 °C retained the highest TPC (14.4 mg gallic acid equivalents (GAE)/g dry weight (DW)), proanthocyanidins (6.8 mg catechin equivalents (CE)/g DW), TFC (13.2 CE/g DW), caffeine (2.9 mg/g DW) and antioxidant capacity. Chlorogenic acid (3.4 mg/g DW) was 13% lower, but energy consumption was 37% less than vacuum drying at 90 °C. Therefore, vacuum drying (3.75 mmHg) at 110 °C for 4h 05 min was suggested for dehydration of the wet coffee pulp for subsequent recovery and processing.

Production and characterization of freeze-dried banana slices pretreated with ascorbic acid and quince seed mucilage: Physical and functional properties

The objective of this investigation was to illustrate the effects of quince seed mucilage (QSM) and ascorbic acid pretreatments to prevent the quality of freeze-dried banana slices. The studied parameters were moisture content, antioxidant activity, total phenol, color properties, structural properties, and sensory evaluation. Both treatments were effective in protecting total phenolic content and antioxidant activity in dried banana slices (P ˂ .05). The control slices showed greater increase in browning index (BI) and greater decrease in lightness (L*) than pretreated dried samples. Ascorbic acid and QSM treatments can be effective in the control of the enzymatic browning along with maintaining the quality properties of banana chips. Therefore, using of immersion pretreatment with 0.25% QSM and 0.05% ascorbic acid is recommended to prevent enzymatic browning as well as maintain the quality of banana chips before the drying process.

The protective effect of Hibiscus sabdariffa calyxes extract against cypermethrin induced oxidative stress in mice

Cypermethrin (Cyp) is a kind of pyrethroids compound that is broadly used against different species of insects and pests. Cyp can also elicit a range of neurotoxic, immunotoxic, genotoxic and reproductive toxic effects on various experimental organisms. The aim of this study was to evaluate the protective effects of Hibiscus sabdariffa against the toxicity damage induced by Cyp exposure. The Hibiscus sabdariffa calyxes extract was given to mice (200-500 mg/kg bw). The mice, which were treated with Cyp and Hibiscus sabdariffa, were divided into six groups of six mice each. Groups I, IV and VI were used as control and groups II C_YP control (20 mg/kg body weight)., groups III and V were treated with Hibiscus sabdariffa extract (200 and 500 mg/kg body weight) plus (20 mg/kg body weight) for 21 days Furthermore, HPLC was used to identify the compound fraction. This result showed Cyp -induced biochemical changes in all organs of mice. Cyp caused decreased CAT activity, inhibition of AChE activity and increased the levels of H₂O₂ and MDA in brain, heart, liver and kidney. Hibiscus sabdariffa exhibited antioxidant effect and significantly attenuated the neurotoxicity of Cyp. Hibiscus sabdariffa exhibits neuroprotective effects and can be an effective and novel alternative approach to reduce the risk caused by pyrethroid compound.

Enrichment of Mango Fruit Leathers with Natal Plum (Carissa macrocarpa) Improves Their Phytochemical Content and Antioxidant Properties

Natal plum fruit (Carissa macrocarpa) is indigenous to South Africa and a rich source of cyanidin derivatives. Indigenous fruits play a major role in food diversification and sustaining food security in the Southern African region. Agro-processing of indigenous are practiced adopted by the rural African communities in order to reduce the postharvest wastage of fruit commodities. In the current study, Natal plum was added to mango pulp at different ratios (mango and Natal plum (5:1, 3:1, 2:1)) to develop a healthy-functional snack (fruit leather). The effects of added Natal plum on the availability of antioxidant constituents and in vitro antioxidant properties of a mango-based fruit leather were evaluated by comparing with mango fruit leather. Fruit leather containing mango and Natal plum (2:1) retained the highest content of cyanidin-3-O-glucoside chloride, cyanidin- 3-O-β-sambubioside, epicatechin, apigenin, kaempferol, luteolin, quercetin-3-O-rhamnosyl glucoside, catechin, quinic, and chlorogenic acids, and in vitro antioxidant activity. Proximate analysis showed that 100 g of fruit leather (2:1) contained 63.51 g carbohydrate, 40.85 g total sugar, 0.36 g fat, and 269.88 cal. Therefore, enrichment of mango fruit leather with Natal plum (2:1) increases its phytochemical content and dietary phytochemical intake, especially for school children and adolescents.

How to objectively determine the color of beer?

Beer color is an important sensory attribute, the first one that the consumer observes. There are two standard methods accepted for determining the color of these products, one related to the European Brewery Convention (EBC) and the other is the Standard Reference Method (SRM). Both methods are based on absorbance, but in case of the more and more popular fruit beers these methods give false result since these products appear in varied colors and have different spectra than regular beers. In this study 39 different types of beers were investigated, including fruit beers and beer based mixed drinks to compare their color in CIE 1976 L*a*b* color space, absorption-based colors and transmission spectra. ΔE*_ab values of products with less than 5% EBC difference ranged from 4.5 to 17.4. There were magnitude differences in the transmission spectra of these products, fruit beers showed different tendencies due to the added fruit or fruit juice. The highest ΔE*_ab value belonged to two traditional Weissbiers. Absorption-based methods are not able in many cases to differentiate between products which have nearly the same EBC or SRM color but visually are different. A multi-wavelength method would be reasonable to be developed for more objective and accurate beer color determination.

ABTS On-Line Antioxidant, α-Amylase, α-Glucosidase, Pancreatic Lipase, Acetyl- and Butyrylcholinesterase Inhibition Activity of Chaenomeles Fruits Determined by Polyphenols and other Chemical Compounds

This study aimed to identify and quantify the chemical composition and polyphenolic profile of 19 cultivars of Chaenomeles × superba, Chaenomeles japonica, and Chaenomeles speciosa by liquid chromatography coupled with photodiode array detector and quadrupole time-of-flight electrospray ionization mass spectrometry (LC-PDA-QTOF-ESI-MS). Antioxidant (ABTS on-line, ABTS, FRAP, and ORAC), as well as in vitro biological activities, i.e., the ability to inhibit α-amylase, α-glucosidase, pancreatic lipase, acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and 15-lipoxygenase (15-LOX) were determined. Most of the Chaenomeles species and cultivars analyzed in this study have not been examined in this respect until now. Fruits contained 30.26 to 195.05 mg of vitamin C, 0.65 to 1.69 g of pectin, 0.32 to 0.64 g of ash, 0.60 to 3.98 g of sugars, and 41.64 to 110.31 g of organic acids in 100 g fresh weight. The lowest content of total polyphenols showed C. speciosa ‘Rubra’ (57.84 g/kg dry weight, dw) while C. × superba ’Nicoline’ (170.38 g/kg dw) exhibited the highest concentration of those compounds. In the phenolic compounds, polymeric procyanidin fraction predominated (65%) with procyanidin B2, C1, and (−)-epicatechin the most abundant. The antioxidant capacity measured by ABTS assay was mainly formed by polymeric procyanidins and flavan-3-ols, which was confirmed by ABTS on-line profiling. Chaenomeles fruits showed high potential for inhibition of α-glucosidase and pancreatic lipase. The analyzed cultivars displayed greater potential for acetylcholinesterase (AChE) inhibition than for butyrylcholinesterase (BuChE). The data indicate that Chaenomeles fruits could be regarded as a promising source of bioactive functional food.

Analysis of the cheese components’ influence on the dehydration process under reduced pressure

This work is aimed at studying the influence of various components’ content on the process of vacuum dehydration. It was found that with an increase in the proportion of fat in dry matter from 10 to 20 %, the duration of disinfection increases by 4 %. The further grows of the fat proportion from 20 to 50 increases the process duration by 54 %. It was revealed, when cheeses, with the fat proportion equal from 10 to 50 %, a change their fat proportion by 1 %, the duration of dehydration decreases by 4.25 minutes, and the drying rate grows by 0.0065 %/min. It has been discovered that with an increase in the table salt concentration with the same mass fraction of cheese moisture 53–55 %, a decrease in the rate of dehydration is observed as well. In the period with a constant drying rate at a concentration of sodium chloride of 1 %, the drying speed is 0.98 %/min; 2 % – 0.8 %/min; 3 % – 0.72 %/min; 4 % – 0.54 %/min. The amount of water activity in cheeses was investigated. It was established that with an increase in the concentration of table salt from 1 to 4 %, the water activity of cheese before drying changes by 0.131; after drying – by 0.174.

Postharvest changes in phenolic compounds and antioxidant capacity of apples cv. Jonagold growing in different locations in Europe

Apples cv. 'Jonagold' of the same quality were collected from four orchards in three European countries. The orchards differed in terms of longitude, latitude and microclimate. The apples were stored in controlled atmosphere storage for six months. Both after harvest and after storage the apples were compared in terms of physical and chemical properties. Differences in firmness, titratable acidity, total soluble solids, mass varied not >11%. Storability was little affected by harvest location. The sum of polyphenols was more strongly influenced by storage than by orchard location. The strongest degradation of flavonols after storage was in apples grown in the most southern region of harvest (Italy). The content of (+)- catechin and (-)-epicatechin depended on harvest location and its strong increase resulted in higher content of procyanidins and flavanols after storage. Changes in individual polyphenols were significant after storage and depended on harvest location.

Effects of three drying methods on polyphenol composition and antioxidant activities of Litchi chinensis Sonn

The aim of this study was to investigate the effects of three different drying methods, freeze drying (FD), vacuum drying (VD) and oven drying (OD) on phenolic contents and antioxidant activities of litchi fruits. 20 polyphenols were exactly identified in the litchi fruits by UPLC-QqQ/MS. Significant losses were observed in the contents of total polyphenols and antioxidant activities in the dried litchi when compared with the fresh litchi. Principle component analysis indicated that there was significant difference of phenolic component between the use of thermal drying (VD and OD) and FD. Our results suggest that FD is the optimum drying method for litchi fruits considering the content of total polyphenols and antioxidant activities.

Effect of different pretreatments followed by hot-air and far-infrared drying on the bioactive compounds, physicochemical property and microstructure of mango slices

In recent years there is an increasing interest in dried fruits, although many of their nutritional components are readily lost during drying. The novelty of this paper was to assess the effect of hot-air drying (HAD) and far-infrared drying (FIRD) on the physicochemical properties and microstructure of mango slices pretreated with: control; 0.1% citric acid + 0.5% ascorbic acid + 0.5% CaCl₂ + 1% NaCl; or 0.1% citric acid + 0.5% ascorbic acid + 0.5% CaCl₂ + 1% NaCl + ultrasound treatments. Pretreatments resulted in a significant (p < 0.05) increase in reducing sugar, ascorbic acid and total phenol contents of dried samples. Moreover, compared with HAD, FIRD maintained a higher phenolic acid content, improved the nutrient retention and color attributes and better preserved microstructure. Therefore, pretreatments followed by FIRD is a potential method for obtaining high-quality dried mango slices.

The application of unconventional technologies as pulsed electric field, ultrasound and microwave-vacuum drying in the production of dried cranberry snacks

A lot of effort is put to decrease the energy consumption of drying. This effect might be achieved by shift of a drying technology e.g. from a hot-air to a microwave-vacuum method. Moreover, an unconventional pre-treatment such as ultrasound or pulsed electric field may modify a cellular tissue, what influences drying kinetics of plant tissue. The aim of the study was to analyse the quality of microwave-vacuum dried, osmodehydrated (OD) cranberries processed by the means of blanching and ultrasound (US) or blanching followed by pulsed electric field and sonication (PEF + US) in comparison to traditionally treated material. Physical, chemical and sensorial properties of cranberry fruits were assessed. What is more, the impact of aforementioned unconventional treatments on the kinetics of microwave-vacuum dried cranberries was studied. Microwave-vacuum drying process was very short (25-38 min) in comparison to convective drying, which lasted several hours (13.2 h). Most of the samples subjected to US and PEF + US treatments before OD and drying were characterized by similar or a higher amount of bioactive compounds such as polyphenols, anthocyanins and flavonoids, and better colour and taste, as compared to cut osmodehydrated cranberry fruits subjected to convective drying (reference samples).