Influences of freeze- and spray-drying vs. encapsulation with soy and whey proteins on gastrointestinal stability and antioxidant activity of Mediterranean aromatic herbs

The aim of the present research was to study the chemical profile of volatile and non-volatile compounds in freeze- and spray-dried oregano, thyme, sage, and rosemary as well as to study the gastrointestinal stability and the biological activity of the samples after encapsulation using two proteins (soy and whey). Chemical analysis was performed by HS-SPME/GC-MS and HPLC-PDA techniques. The antioxidant activity (FRAP, DPPH and ORAC assays) and HPLC-PDA analyses were performed before and after simulated two-phase digestion process (gastric and duodenal) using human gastrointestinal enzymes. The effect of protein carriers was depended on the plant matrix and the class of compound. Soy protein is useful for the protection of thymol and carvacrol content in thyme and the increase of the antioxidant activity of sage. Whey protein is useful for flavanols stability in all studied herbs before and after the duodenal digestive phase.     

Berry fruits-enriched pasta: effect of processing and in vitro digestion on phenolics and its antioxidant activity,bioaccessibility and potential bioavailability

Pasta samples were made by substituting wheat flour (2.5% and 7.5%) for lyophilised raspberry, boysenberry, and redcurrant and blackcurrant. Total polyphenol content showed minimum variation during processing while anthocyanins presented high degradation. In general, the first minutes of cooking showed the major detrimental effect on antioxidant activity. In vitro starch hydrolysis showed the lowest value with the addition of raspberries and boysenberries. During simulated digestion, polyphenols were released from pasta matrix reaching a 2.3- to 4.3-fold increase in bioaccessible polyphenols. Likewise, values observed for reducing power and free radical scavenging activity ranged from a 0.7- to 2.0-fold and 1.6- to 6.8-fold increase in relation to cooked pasta, respectively. In addition, ≈40% of dialysability was observed for scavenging activity. In conclusion, enrichment of pasta with fine fruits is an effective tool to obtain a product with enhanced antioxidant potential.     

Total phenolics, flavonoids and antioxidant activity of tropical fruit pineapple

Pineapple has several beneficial properties including antioxidant activity. The fruit of pineapple was extracted with ethyl acetate, methanol and water. The phenolic content of the extracts was determined by Folin-Ciocalteu method and antioxidant activity was assayed through some in vitro models such as antioxidant capacity by phosphomolybdenum, ??-carotene-linoleate, and radical scavenging activity using ??,??-diphenyl-??-picrylhydrazyl (DPPH) method. The phenolic contents of the extracts as caffeic acid equivalents were found to be highest in methanol (51.1%) followed by ethyl acetate (13.8%) and water extract (2.6%). Antioxidant capacity of the extracts as equivalent to ascorbic acid (??mol/g of the extract) was in the order of methanol extract > ethyl acetate extract > water extract. In comparison with butylated hydroxyanisole (BHA), at 100 ppm of concentration, the antioxidant and free radical scavenging activities of the extracts assayed through ??-carotene-linoleate and DPPH method were also found to be highest with methanol extract followed by ethyl acetate and water extracts. The results indicated that the extent of antioxidant activity of the extract is in accordance with the amount of phenolics present in that extract and the pineapple fruit being rich in phenolics may provide a good source of antioxidant.     

黑果枸杞中多酚的体外消化及其抗氧化性研究

以黑果枸杞为原料,研究了化学提取法和体外消化法两种不同提取方式对多酚含量的影响。同时,采用DPPH、FRAP、ABTS和ORAC四种不同方法测定了枸杞提取物的抗氧化性。结果表明,体外消化处理后的总酚和总花色苷含量低于化学提取法,而酚酸含量则高于后者;总体上,化学提取法的抗氧化性高于体外消化法;两种提取方法处理后的总酚和总花色苷与各化学抗氧化值均有较高的线性相关性(R2>0.83)。而体外消化法中,酚酸与各化学抗氧化值的相关性(R2>0.68)明显高于化学提取法(R2>0.03)。      

Effect of in vitro‐simulated gastrointestinal digestion on the stability and antioxidant activity of blueberry polyphenols and their cellular antioxidant activity towards HepG2 cells

In this study we investigated the influence of in vitro‐simulated gastrointestinal digestion on the bioaccessibility and antioxidant activity of polyphenols from blueberries (Vaccinium spp.). Total phenolic, anthocyanin, and flavonoid content was determined, and extract and digesta compositions were analysed by HPLC‐ESI‐MS/MS. The phenolic compounds were relatively stable under a gastric environment, whereas polyphenols and anthocyanins were unstable under an intestinal environment. The bioaccessibility of polyphenol, anthocyanin, and flavonoid was greatly decreased after the intestinal digestion, and the recoveries were only 13.93%, 1.95%, and 15.68% (the IN sample), respectively. Polyphenolic profile alteration occurred during in vitro‐simulated gastrointestinal digestion. Changes of phenolic compound antioxidant activity during digestion correlated with polyphenol, flavonoid, and caffeic acid concentrations. Digested extract cellular antioxidant activity was lower than non‐digested extract activity (P < 0.05). Polyphenol dose–response correlations with cellular antioxidant activity were observed. These results indicated that in vitro‐simulated gastrointestinal digestion significantly impact polyphenols and their antioxidant activity.     

Influence of in vitro gastrointestinal digestion on the bioavailability and antioxidant activity of polyphenols from Ipomoea batatas leaves

Sweet potato leaves (SPL) are natural by‐products rich in bioactive compounds, particularly polyphenols, and can be consumed as a vegetable. This work aims to investigate the influence of in vitro gastrointestinal digestion on the bioavailability and antioxidant activities of polyphenols from SPL. The phenolic compounds of sweet potato leaf extracts (SPLE) were quite stable in gastric phase. However, the amount of phenolic compounds decreased during transition from the acidic gastric environment to the alkaline intestinal environment. The bioavailability of phenolic compounds of SPLE was 13.36%. The ABTS^·+ scavenging capabilities and reducing power of SPLE were not affected during gastric digestion. Antioxidant activity increased after intestinal digestion. This research suggested that phenolic compounds of SPLE were sufficiently available for absorption. This study also provides useful information on the potential commercial value of SPL.     

成熟期对冬枣多酚含量及其抗氧化活性的影响

研究了全绿、绿白、半红和全红四个成熟期冬枣果实的果皮和果肉中游离态、酯化态和结合态的酚含量以及其总抗氧化能力、清除DPPH自由基和铁还原能力的变化。结果表明,冬枣果实酚类物质主要以游离态和酯化态形式存在于果皮当中,全红期果皮以结合态为主。冬枣果皮中游离态和酯化态酚类物质对总抗氧化能力、清除DPPH自由基和铁还原能力起主要作用。半红期冬枣果实酚含量最多以及其抗氧化活性最为突出。      

Effect of thermal treatment on the antioxidant activity of egg white hydrolysate and the preparation of novel antioxidant peptides

Heat treatment will affect the nutritional properties and potential bioactivity of food materials. The aim of this work was to evaluate the effect of different thermal treatment (4, 56, 65 and 100 ℃) and in vitro gastrointestinal digestion on the antioxidant activity of egg white hydrolysate. The results demonstrated that egg white hydrolysate treated at 65 ℃ exhibited the highest antioxidant. Remarkably, the simulated digestion significantly increased antioxidant activity of egg white hydrolysate. Furthermore, we identified twenty-four potential antioxidant peptides by performing mass spectrometry and bioinformatic analysis. Six peptides were selected based on the activity prediction score of the online tool. The results showed that P6 (ACPECPK) possessed the most outstanding antioxidant properties and had low cytotoxicity and allergenicity. Bioinformatics technology combined with biochemical assays may offer a way for discovering novel antioxidant peptides from different kinds of food under various heat treatment conditions.     

In vitro gastrointestinal digestion of mango by-product snacks: Potential absorption of polyphenols and antioxidant capacity

Mango by-products are considered cheap sources of valuable foods and nutraceutical ingredients. In this work, antioxidant capacity (AOX), and potential absorption ability (PAA) of extractable polyphenols (EP) from mango by-product snacks (MB-S) were evaluated at different stages of in vitro gastrointestinal digestion. A wheat and oat-based control snack and three MB-S formulations (F1, F2 and F3) were prepared. Mango by-products were added at the expense of wheat in MB-S (paste-peel-seed): F1 (70-30-0), F2 (70-15-15), F3 (70-7.5-22.5). The highest release of polyphenols was observed after the gastric digestion. In the intestinal stage, MB-SF1 was the snack with the highest EP content (23.39 mg GAE/g db), two times greater than the control. Gallic acid and mangiferin were the main polyphenols identified in MB-S. The incorporation of mango seed in the MB-S reduced the polyphenols PAA by 10.29%. However, compared with the control snack, consumption of 30 g MB-SF1 provided additional 45 mg polyphenols.     

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.     

Studies on retention of antioxidant activity,phenolics and flavonoids in high pressure processed black grape juice and their modelling

The effect of high pressure processing on total antioxidant activity, phenolic and flavonoid content of black grapes juice was studied. Response surface methodology (RSM) was used for designing the experiment keeping high pressure (400–600 MPa), temperature (40–60 °C) and processing time (2–4 min) as independent variables. The data obtained were analysed using multiple regression technique and quadratic models were found to fit well (R², 85.61–96.65%) in describing the effect of high pressure, temperature and time on total antioxidant activity, phenolics and flavonoids. The optimum levels were found to be 550 MPa, 44 °C and 2 min for pressure, temperature and processing time, respectively (desirability, 95.00) for getting the maximum retention of total antioxidant activity, phenolics and flavonoids in the juice. The experimental and predicted valued of responses showed high correlation (R², 99.26–99.90%) at the optimised levels of the variables.     

Oxidative stability and antioxidant activity of bovine,caprine, ovine and asinine milk

This study compares the oxidative stability of fat isolated from bovine, caprine, ovine and asinine milk as well as the antioxidant activity of casein and whey from these milks. Fat from bovine and asinine milk showed the highest oxidative stability. The antioxidant activity of casein and whey was examined before and after an in vitro digestion process. Whey from asinine milk showed the highest antioxidant activity. The antioxidant activity of whey and casein increased after simulated intestinal digestion. In addition, the results of this study showed that asinine whey exhibited radical scavenging activity comparable with the strong synthetic antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).     

In vitro bio-accessibility and antioxidant activity of grape polyphenols

The bio-accessibility (the release of compounds from solid food matrices) of grape polyphenols using an in vitro model simulating gastro-intestinal conditions has been investigated. In vitro studies are needed to unravel factors affecting the release of antioxidants during digestion. The amount of bio-accessible polyphenols, flavonoids and anthocyanins increases during gastric digestion. The transition in the intestinal environment causes a decrease in all the analyzed classes of polyphenols followed by a renewal in the extraction of polyphenols and flavonoids but not of anthocyanins. The stability under gastro-intestinal conditions of pure phenolic acids, flavonoids and resveratrol has been analysed. Gastric digestion had no effect on any phenolic tested. Phenolic acids and resveratrol were degraded under pancreatic conditions whereas catechin and quercetin were not. Changes in antioxidant activity during digestion were correlated to the changes in polyphenols concentration as well as to the pH. Our results suggest that the gastro-intestinal tract may act as an extractor where polyphenols are progressively released from solid matrix and made available for the absorption or to exert their biological effects in the gastro-intestinal tract.     

Anthocyanins profile,total phenolics and antioxidant activity of black currant ethanolic extracts as influenced by genotype and ethanol concentration

Ethanolic extracts prepared from the fruits of three cultivars of black currant (‘Record’, ‘Blackdown’ and ‘Ronix’) macerated in three concentrations (40%, 60% and 96%) of aqueous ethanol were investigated for their anthocyanins profile, total phenolics and antioxidant activity.     

发芽对糜子酚类化合物及抗氧化活性的影响

探讨了发芽时间对糜子中酚类化合物含量、存在形式及抗氧化活性的影响。将经过表面灭菌的糜子种子放入25℃,相对湿度95%的人工气候箱中避光发芽6 d,每天取样,测定其中酚、黄酮含量及抗氧化指标（DPPH、ABTS、FRAP、ORAC）的变化。结果显示,从发芽2 d起,酚、黄酮含量及各项抗氧化指标明显增高。发芽6 d后,内糜8号总酚、总黄酮含量分别为发芽前的5.9和1.9倍,西农10-04号则分别为发芽前的4.6和1.9倍,抗氧化能力均显著增强（p<0.05）。此外,发芽4 d后芽中总酚、总黄酮含量及抗氧化能力显著高于（p<0.05）相应种子。总酚、总黄酮与抗氧化能力间均显示出极强的相关性,其中以总黄酮与FRAP相关性最高（r=0.985）。研究表明,发芽是一种有效提高糜子中酚类化合物含量及抗氧化活性的加工方式。      

体外模拟消化对酸枣仁蛋白酶解产物抗氧化活性的影响

目的:以具有良好抗氧化活性的酸枣仁蛋白酶解产物(SZPHs)为研究对象,探究体外模拟胃肠消化对其氨基酸组成及抗氧化活性的影响.方法:通过体外模拟胃肠消化,得到酸枣仁蛋白酶解产物消化物(SZPHs-GD),并分析SZPHs消化前后的氨基酸组成以及体外抗氧化活性.结果:体外模拟胃肠消化后,SZPHs-GD中疏水性氨基酸含量...     

体外模拟胃肠消化对缢蛏抗氧化活性的影响

目的 基于体外模拟消化系统探究胃肠模拟消化对缢蛏的抗氧化活性的影响以及氨基酸含量的变化。方法 以新鲜缢蛏为原料,向体外模拟消化系统加入胃蛋白酶和胰蛋白酶,模拟在胃液和肠液下的胃消化、十二指肠消化和小肠消化过程,研究缢蛏在消化过程中的羟基自由基(·OH)清除率、二苯代苦味酰基自由基(2,2-diphenyl-1-picrylhydrazyl radical, DPPH·)清除率、还原力、水解度、游离氨基态氮及游离氨基酸含量的变化。结果 整个胃肠消化阶段,加酶组的·OH清除率、DPPH·清除率、还原力均高于对照组。肠消化产物的·OH清除率、DPPH·清除率、还原能力及水解度均高于胃消化产物,并且肠消化产物中的总游离氨基酸含量及具有抗氧化特征的氨基酸含量均显著高于胃消化产物(P<0.05)。在十二指肠消化阶段,·OH清除率、DPPH·清除率、还原力值达到最高。结论 体外模拟消化处理能够提高缢蛏的抗氧化活性,其中十二指肠消化阶段产物抗氧化活性最高。     

食品级κ-卡拉胶对肥胖小鼠致结肠炎风险及体脂蓄积的影响

卡拉胶与酪蛋白的结合对肠道屏障具有一定的保护作用,为研究两者在体外消化模拟中消化酶是否是影响多糖或多糖-蛋白复合体系构象转变的主要因素,本文以κ-卡拉胶为研究对象,选择酪蛋白为基质,探究体外模拟消化环境中消化酶对κ-卡拉胶/酪蛋白复合体系结合稳定性的影响。结果表明,消化酶对κ-卡拉胶与酪蛋白的结合影响不大,但可以使体系硫酸基团暴露量显著增加,不利于κ-卡拉胶的构型。体系中的酪蛋白被分解为低分子量的蛋白质或肽段,使得复合体系的特征长度增加,相互作用减弱,粘弹性下降,双螺旋结构稳定性降低。本研究为κ-卡拉胶的安全应用提供了理论依据。