Effects of temperature during processing with wine on chemical composition,antioxidant capacity and enzyme inhibition activities of Angelica Sinensis Radix

The effects of temperature (100 °C, 150 °C, 250 °C) during processing with wine on chemical composition, oil oxidative stability, inhibitory activities on acetylcholinesterase (AChE) and pancreatic lipase (PL) of Angelica Sinensis Radix (ASR), and the feasibility of melanoidins as a colour index to control the roasting intensities were investigated for the first time. The results showed that there were the highest content of ferulic acid, total flavonoids and antioxidant activity of sample roasted at 150 °C, and the sample roasted at 250 °C had the highest content of polysaccharide and total phenolics. A continued reduction in volatile content has occurred in progressive roast. The oxidant stability of oil has a slight increase along with the strength of the roasting intensities, which was higher than unprocessed ASR. Inhibitory activities on acetylcholinesterase and pancreatic lipase were decreased firstly and then increased. Melanoidins can be used as a colour indicator for controlling the thermal processing.     

Effects of high hydrostatic pressure on the quality and shelf-life of jujube (Ziziphus jujuba Mill.) pulp

This study evaluated the effects of high hydrostatic pressure (HHP) on the microbial counts, physicochemical properties, bioactive compounds, and antioxidant capacity of jujube pulp. Additionally, this study compared the shelf life of jujube pulp following HHP (600 MPa/20 min) and thermal treatment (100 °C/10 min) during 40 days of storage at 4 °C and 15 °C. The microbial count of HHP-treated jujube pulp (≥ 400 MPa/20 min) was below the detection limit. Total soluble solids and total sugars were not significantly affected by HHP processing, and > 90% ascorbic acid was retained in HHP-treated samples. HHP slightly reduced pH and browning degree and increased total phenolic content, flavonoid content, and antioxidant capacity. HHP can be used as an alternative to thermal pasteurization of freshly squeezed jujube pulp.Industrial relevanceEffects of high hydrostatic pressure (HHP) processing and thermal treatment (TT) on microbiological quality, physicochemical properties, bioactive compounds and antioxidant activity in jujube pulp were investigated. Greater inhibition of microorganisms and better retention of ascorbic acid, total phenolics, flavonoid and antioxidant capacity were observed after HHP-treatment. The available data could be used to design the HHP parameters for high quality jujube juice. Further, this research would provide a useful method for preservation of jujube products and potential technical support for jujube commercial production.     

Accumulation of phenolics,antioxidant and antiproliferative activity of sweet corn (Zea mays L.) during kernel maturation

Phenolic profiles and gene expression pattern in their synthetic pathway, total antioxidant activities and antiproliferative activities in two genotypes of sweet corn (YT16 and YT28) during kernel maturation were analysed. Results showed that increasing trends of phenolics and flavonoids in the two genotypes of kernels from 10 to 30 days after pollination (DAP). Gallic acid, chlorogenic acid, p-coumaric acid and ferulic acid were identified and quantified as the main phenolic compounds in both genotypes of kernels. High expressing levels of C4O and PAL resulted in the increasing phenolic contents. Higher expressing levels of CHS in YT28 led to higher flavonoid contents than that in YT16. The phenolic contents, antioxidant capacities and antiproliferative abilities of the two genotypes of sweet corn were competitive comparing to many fruits and vegetables. In addition, the maturation process of sweet corn could raise the kernel’s bioactive ability as well as nutritional values.     

Comparative study of phenolic content and antioxidant activity of strawberry puree,clear, and cloudy juices

The aim of this study was to determine the concentrations of phenolic compounds and their antioxidant activity in different kinds of juice: clear, cloudy, and puree which were made from three different strawberry cultivars (Elkat, Kent, and Senga Sengana). The anthocyanins, p-coumaric acid, ellagic acid, quercetin, keampferol derivatives, (+)-catechin, proanthocyanidins content and degree of proanthocyanidin polymerization, were determined both in the fresh and after 6 months of storage at 4 and 30 °C. Freshly produced juices contained higher amounts of phenolics, especially of anthocyanins and proanthocyanidins, than those stored for 6 months at 4 and 30 °C. The processing of the clear juice showed the higher loss of all phenolic compounds. The antioxidant capacity was the smallest for clear, and the highest for the puree juices. This was assessed by measurements made with different antioxidant activity assays: ABTS and FRAP. The puree of strawberry juice had significantly higher levels of the phenolic compounds and showed more antioxidant activity than the clear and cloudy juices, before and after storage in all strawberry cultivars.     

Phenolic content and antioxidant activity of eight representative sweet corn varieties grown in South China

In the present study, phenolic content and antioxidant capacities including cellular antioxidant activity of eight Chinese sweet corn varieties were investigated. The total phenolic content revealed significant varietal differences and phenolics existed mainly in free form. HPLC analysis showed that ferulic and p-coumaric acids were the dominating phenolics in sweet corn. The DPPH scavenging capacity, ferric reducing antioxidant power, and cellular antioxidant activity demonstrated distinct varietal differences, which were positively correlated with their phenolic content, although the orders of antioxidant activity of eight varieties determined by three different methods were not consistent. Sweet corn could be a better substitute for many commonly consumed vegetables in terms of phenolics and antioxidant activity.     

Effects of Blanching on Some Physical Properties and Processing Recovery of Sweet Corn Cobs

The effects of the blanching process of sweet corn on shearing stress, shearing energy, and processing recovery of kernels as well as weight and dry substance of kernels and cobs were studied. Sweet corn cobs were blanched in water, where blanching time ranged from 2 to 8 min and temperature ranged from 75 to 100 °C. Nonblanched cobs (fresh cobs) were used as control samples. It was found that all analyzed variables were significantly affected by blanching time and temperature. The average values of all analyzed variables, except moisture which decreased, increased with increasing of the blanching time and temperature. Changing the blanching time and temperature affected the dry substance of kernels and cobs, kernel and cob mass, recovery processing by increasing it, as well as the average values of shearing stress and shearing energy by decreasing them.     

Functional properties of wheat kernels (Triticumaestivum L.) during storage

The method of storage has, in the long run, a negative effect on the quality of wheat kernels, due to physiological ageing of its cells.The quality of the kernels was assessed during the storage, giving the predefined conditions - temperature 25 ± 2 °C and the storage duration.Wheat kernel metabolites were studied during 12 and 24-month storage. Kernels of three commercial wheat cultivars – ‘Simonida’, ‘Dragana’ and ‘Ljiljana’, commonly grown in south-eastern Europe, were investigated. Comparing fresh samples to samples taken after 12 and 24 months of storage, it was recorded with an increase in dry matter (by 2.48% and 2.84%) and ash (by 4.09% and 15.25%), and a decrease in protein (by 8.96% and 19.81%), lipids (by 8.32% and 15.07%), starch (by 9.07% and 13.45%) and cellulose (by 22.12% and 26.35%). There were also changes in phenolics (10.51–11.82 mg GA/g). Flavonoid vitexin-glucoside (0.82–1.29 mg/g) and flavan-3-ol catechin (1.31–1.60 mg/g), total antioxidant potential and DPPH scavenging activity were not significantly different. Organic matter digestibility (OMD) decreased, but remained at 92%. These changes did not significantly affect key properties of the kernels, OMD and antioxidant activity, thus wheat kernels can be safely stored for 24 months.     

Effect of storage on the bioactive compounds and antioxidant activity of quince nectar

The changes of bioactive components and antioxidant activity of quince nectar were determined during 9 months of storage at 5, 20, 30 and 40 °C. The amount of total phenolics, flavonoids and antioxidant activity was significantly declined during storage at all temperatures. Loss of L‐ascorbic acid at 5, 20, 30 and 40 °C was 32.08%, 43.69%, 65.21% and 88.82%, respectively. L‐ascorbic acid degradation was in accordance with the first‐order reaction kinetics, and activation energy was found as 43.65 kJ mol^?1. After 9 months of storage, Hydroxymethylfurfural (HMF) contents of quince nectars were 15.01, 16.64, 21.69 and 57.89 mg kg^?1 at 5, 20, 30 and 40 °C, respectively. HMF accumulation fitted a zero‐order kinetic model, and activation energy was found as 88.30 kJ mol^?1. A significant correlation was found among L‐ascorbic acid, total phenolics, flavonoids and antioxidant activity.     

Effect of Blanching and Drying Temperature on Polyphenolic Compound Stability and Antioxidant Capacity of Apple Pomace

The effects of blanching and drying treatments on stability, physical properties, and antioxidant activity of apple pomace polyphenols were evaluated. Blanched and unblanched apples were extracted, and the pomace was dried in a cabinet dryer at a speed of 3 m/s at 50 °C, 60 °C, 70 °C, and 80 °C. The color, total phenolics, flavonoids, individual polyphenolic compounds, anthocyanins, and total antioxidant activity were analyzed. The blanching process caused a major retention in color, total polyphenolic content, and total flavonoid content for fresh apple pomace when compared with fresh unblanched pomace. Drying of either fresh blanched or fresh unblanched pomace caused a significant reduction (P < 0.05) in total polyphenol and flavonoid content leading to a reduction in the total antioxidant activity. When compared with the unblanched treatment, drying the blanched pomace at 80 °C resulted in a product with significant amounts of total phenolics, flavonoids, and antioxidant activity. The individual phenolic compounds were significantly increased (P < 0.05) in blanched pomace that was not dried when compared with unblanched samples. Drying blanched apple pomace did not cause a significant change in the concentration of individual polyphenolic compounds, but drying unblanched apple pomace caused a reduction in the concentrations of epicatechin and caffeic acid, with an important reduction in p-coumaric acid at temperatures higher than 60 °C. However, the drying process caused a significant reduction in the antioxidant capacity. Therefore, a combination of blanching and drying processes for apple pomace results in a product that maintains antioxidant capacity.     

FLAVOR AND TEXTURE OF PRESERVED INTACT SWEET CORN: COMPARISON WITH CUT SWEET CORN AND STORAGE TESTS

Sensory studies were conducted to determine if intact or unit kernels of sweet corn (i.e. kernels which are detached at their normal abscission layer and lack a cut surface) can replace cut kernels. Samples of intact or unit kernel sweet corn were compared hedonic-ally and by relative preference with samples of cut sweet corn after appropriate processing. Stability of the frozen and canned intact kernels was studied for one year. Hedonic ratings for frozen intact corn yielded values of 7.4–7.6 and compared to values of 6.0–6.2 for cut corn. Hedonic ratings for canned intact corn yielded values from 6.4–6.8 and compared to values of 5.9–6.1 for cut corn. Laboratory taste panels expressed preference for intact samples in 86–89s of the judgements of frozen corn and in 64–86s of the judgements of canned corn. Both flavor and texture of the intact corn were most frequently cited as the reasons for preference. Frozen samples of intact kernels were stable for at least 1 yr at ?18°C. Canned samples of intact kernels of Golden Jubilee and Golden Happiness were stable for 1 yr at 18°C. Sensory differences were detected in Stylepak samples at the 12-month evaluation.     

Changes in content of vitamins A and E in growing‐up milk throughout its shelf life

The stabilities of vitamins A and E were determined in 51 samples of growing‐up milk stored at 23, 30 and 37 °C for up to 9 months. Initially, the content of vitamin A and vitamin E was 330 RE μg/100 mL and 1.78 α‐TE mg/100 mL, respectively. Decreases in vitamin content were higher (P < 0.05) in formulas stored at 37 °C (from 330 to 111 μg RE/100 mL for vitamin A and from 1.78 to 1.16 mg α‐TE/100 mL for vitamin E). Over‐fortification of growing‐up milk could be recommended for vitamin E.     

Effect of thermal processing and digestive protease on the antioxidant capacity of fruit juice–milk beverage model systems under simulated gastrointestinal digestion

The effects of thermal processing and digestive protease on the antioxidant capacity of fruit juice–milk beverage (FJMB) models containing whey protein (WP) and chlorogenic acid or catechin (CAT) under in vitro digestion were investigated. After gastric digestion, the FJMB showed a significant (P < 0.05) increase in ABTS, but little change in ferric reducing antioxidant power (FRAP). Intestinal digestion decreased the FRAP and increased ABTS except in the model containing 0.1% CAT. There were different effects (none, masking, synergistic effect) in the antioxidant activity of the WP and phenolics under digestion. Pasteurisation (63 °C/30 min) had no significant effect on the FJMB's antioxidant capacity, while sterilisation (121 °C/10 min) significantly (P < 0.05) increased, decreased or had no significant effect on ABTS and FRAP under digestion, depending on the model. Pepsin and pancreatin significantly (P < 0.05) decreased the fruit phenolics' ABTS. Ferric reducing antioxidant power was not significantly influenced by pepsin during gastric digestion, but was significantly (P < 0.05) decreased by pancreatin during intestinal digestion. These results would be helpful to improve the efficacy of fruit phenolics in FJMB subjected to thermal processing and to maintain the health benefits of this kind of functional products in the food industry.     

Antioxidant Properties of Cocoa Beans (Theobroma cacao L.): Influence of Cultivar and Roasting Conditions

Effects of various roasting conditions on antioxidant properties of five Theobroma cacao L. varieties were investigated. The cocoa beans were roasted at four different temperatures (110–150°C) and three different air humidities (0.3–5.0%). The raw cocoa beans were characterized by high antioxidant activities. The antioxidant properties of the roasted cocoa beans varied markedly among the analyzed cultivars and geographical regions and were affected by roasting conditions. Generally, cocoa beans of the cv. Forastero from Brazil exhibited higher total phenolic content, free radical scavenging activity, and metal chelating ability than samples of the other analyzed cocoa varieties. Roasting at 110°C caused negligible changes in total phenolics content and antioxidant activity of cocoa beans, while almost all samples tended to have lower antioxidant potential when roasting temperature increased. The air humidity used in roasting did not affect the total phenolics content and antioxidant activity for lowest roasting temperature (110°C). Moreover, the obtained results revealed that thermal processing at the higher temperatures and elevated air humidity resulted in the higher antioxidant capacities. It was also found that the ferrous ion chelating activity of cocoa beans increased with the roasting temperature (in the range from 110 to 150°C), with the exception of cv. Trinitario from Papua New Guinea. The data showed that roasting at lower temperatures with humid air are more favorable in terms of preserving the bioactivity of roasted cocoa beans.     

Comparison of phenolic profiles and antioxidant potentials of the leaves and seeds of Thai holy and sweet basils

Eight phenolics rosmarinic, caftaric, caffeic, chicoric, p‐hydroxybenzoic, p‐coumaric, protocatechuic acid and rutin were identified in Thai holy/sweet basil leaves or seeds. The overall phenolics in THBL were two, three and twenty times higher than that in TSBL, THBS and TSBS, respectively. Oppositely, the TP content of TSBL was one and a half times higher than THBL which was followed by THBS and TSBS. The order of scavenging DPPH free radical activity from high to low was THBL, TSBL, THBS and TSBS and consistent with their overall phenolics. In a cholesterol oxidation model, THBL exhibited higher antioxidant activity with lower level of 7‐ketocholesterol (2.67 ± 0.31 μg/mL) than TSBL (4.49 ± 0.32), THBS (7.78 ± 1.25) or TSBS (13.10 ± 0.61). The results demonstrated that Thai holy basil has higher antioxidant capability than sweet basil and could be used as an effective bioactive ingredient to provide health‐promoting function in food.     

Polyphenolic and antioxidant changes during storage of normal,mid, and high oleic acid peanuts

The quality of dry roasted peanuts is highly dependent on storage conditions for preventing oxidation of fatty acids; however, changes in polyphenolics affecting antioxidant capacity due to co-oxidative reactions are unknown. The objective of this work was to evaluate oxidative stability of polyphenolics in peanut kernels with naturally varying rates of lipid oxidation. Three peanut varieties containing varying levels of oleic acid (normal, mid, and high) were dry roasted and evaluated for phytochemical changes over four months of storage at 20 and 35 °C; analyses included peroxide value, total and individual phenolics and antioxidant capacity. The normal oleic acid peanuts suffered up to 2.6-fold and mid-oleic acid peanuts 2-fold more lipid oxidation than the high-oleic acid peanuts stored at 35 °C. Changes in total soluble phenolics were initially similar among cultivars, but antioxidant capacity was found to decrease by 62%, on average, during storage at 35 °C, independently of rates of lipid oxidation. Free p-coumaric acid, three esterified derivatives of p-coumaric, and two esterified derivatives of hydroxybenzoic acid were the predominant polyphenolics present and their rates of change were similar among cultivars and independent of storage time or temperature. The high-oleic acid content was essential for prevention of lipid oxidation, but data indicated that co-oxidative reactions, affecting polyphenolic content during storage, were not great enough to significantly alter antioxidant capacity.     

High pressure processing (HPP) of honey for the improvement of nutritional value

The present study was undertaken to assess the effect of high pressure processing (HPP) on total phenolic content (TPC) in manuka honey. Manuka honey is known for its amazing antimicrobial action and antioxidant properties. The effect of HPP (200, 400 and 600 MPa) at ambient and moderate temperatures (53.41 ± 0.30 °C, 65.29 ± 1.77 °C, 71.92 ± 1.63 °C) and their combination for different processing time (5, 10 and 15 min) was investigated. Conventional thermal processing (51.74 ± 0.03 °C, 61.90 ± 0.10 °C and 71.58 ± 0.04 °C) was also carried out as comparison to HPP. Operating HPP at 600 MPa (26.80 ± 0.95 °C–30.18 ± 2.14 °C) for 10 min was found to be the most effective process with 47.16% increment in TPC as compared to unprocessed honey, whereas no significant increase (p < 0.05) was observed in thermal processing as well as in combined HPP–thermal processing. Therefore, HPP at ambient temperatures could be an appropriate method to produce tastier and more nutritive manuka honey.Industrial relevanceThe preservation of total phenolic content (TPC) as a main phytochemical component in honey is very important with direct impact on nutritional value and antioxidant activity. A significant increase in the TPC was obtained by processing. Results demonstrated the HPP capability to increase TPC in manuka honey by 47%. From a nutritional perspective, this result is associated with the production of a higher antioxidant honey, known to prevent certain diseases such as cancer. The study generates a new approach in honey processing which can guarantee the high nutritional quality of honey and its original natural freshness.     

Antioxidant Bioactive Compounds in Selected Industrial Processing and Fresh Consumption Tomato Cultivars

Four selected fresh consumption tomato varieties, harvested at different ripening stages (green, breaker, pink, red) and five industrial processing tomato varieties, harvested at red ripe stage, were analysed for lycopene and its isomers, β-carotene, total and individual phenolics, vitamin C and hydrophilic antioxidant activity. Tomato variety and ripening stage significantly affected carotenoids, total phenolic compounds and hydrophilic antioxidant activity when fresh consumption tomatoes were compared. The average of total lycopene content at the different ripening stages was 0.63, 12.20, 26.76 and 116.66 mg/kg of fresh weight (FW). Vitamin C ranged from 2.79 (breaker Cherry Pera) to 297.62 (red Cherry Pera) mg/kg FW. In green and breaker tomatoes, a positive correlation of hydrophilic antioxidant activity with vitamin C and chlorogenic acid was observed. However, in industrial tomato varieties (red ripe stage) and fresh consumption varieties harvested at pink and red stages, hydrophilic antioxidant activity was correlated with total phenolics and rutin. Tomato varieties for industrial processing did not show significant differences in total phenolic compounds and lycopene content. Lycopene ranged from 83.17 to 97.60 mg/kg FW, while total phenolic compounds varied between 257.91 and 284.13 mg/kg FW. Chlorogenic acid and rutin were the most abundant individual phenolics found in all the samples studied. Moreover, the content of total phenolics was always significantly correlated with the content of rutin. The amounts of all individual phenolics were affected by variety, with the exception of ferulic acid. Generally, these individual phenolics were more abundant in green and intermediate ripening stages, decreasing in full red tomatoes.     

The antioxidant activity and the composition of free and bound phenolic acids in dough of wheat flour enriched by Boletus edulis after mixing and thermal processing

The porcino is good source of phenolics and has been used to enrich wheat flour. The antioxidant activity and the content and composition of free and bound phenolic acids in the dough of wheat and porcino flour mixture (70:30 w/w) were investigated. The free form in the amount of 1305.76 μg g^?1 was the main part of the phenolic content in the flour mixture. By dough mixing, the content of free phenolics increased by approximately 70%. Further thermal processing decreased the content of both forms of phenolics compared to dough after mixing, but the content of free phenolics of 1764.24 μg g^?1 is still higher than in the flour mixture. The stability of the detected phenolic acids during mixing and thermal processing depended on whether they were in free or bound form. After thermal processing, the total content of detected phenolic acids was 683.31 μg g^?1, indicating that approximately 87% of the total content of phenolic acids detected in flour mixture was retained.     

Modelling of Vitamin C Degradation during Thermal and High-Pressure Treatments of Red Fruit

Vitamin C is known for its potent antioxidant properties. Since humans lack one of the final enzymes in the biosynthesis of this vitamin, they are dependent on dietary sources for their vitamin C needs. Strawberries are good sources of vitamin C, but the vitamin is unstable during food processing, and high temperatures have shown to induce rapid degradation. As an alternative preservation technique, high-pressure processing is investigated for its potential to achieve pasteurisation and sterilisation conditions at lower process temperatures and shorter treatment times compared to thermal processing. The objective of the present study was to examine quantitatively the effect of processing on vitamin C in strawberry and raspberry matrices by comparing thermal treatments (80–140 °C) to treatments at 700 MPa (60 °C, 90 °C and 110 °C). To this end, a mechanistic model was proposed and tested to fit the degradation of ascorbic acid (AA) and the consecutive formation and degradation of dehydroascorbic acid (DHAA). AA degradation followed a biphasic course: the aerobic reaction was fast and most important, while the anaerobic reaction was slow and only perceptible at temperatures of 120 °C and up. The oxidation of AA to DHAA was slower than the subsequent degradation of DHAA in the strawberry matrix; the opposite was true in the raspberry matrix. Both temperature and pressure enhanced the degradation of vitamin C. The proposed mechanistic model provided reasonably good fits to the experimental data, only to a lesser extent for the DHAA evolution during high-pressure processing.