The effect of time and origin of harvest on the in vitro biological activity of Palmaria palmata protein hydrolysates

The effect of starting protein composition, and the origin and time of harvesting on the in vitro tyrosinase, dipeptidyl peptidase (DPP) IV and angiotensin converting enzyme (ACE) inhibitory and antioxidant activity of Palmaria palmata protein hydrolysates were investigated. Electrophoretic profiles showed significant differences in aqueous protein extracts obtained from the red macroalga Palmaria palmata harvested at different times of the year. No significant difference was observed in aqueous protein profiles extracted from wild and aquacultured samples of Palmaria palmata. Protein extracts from Palmaria palmata samples harvested from wild plants in April, July and October, and samples cultivated on longlines and harvested in April were hydrolysed with Alcalase 2.4 L and Corolase PP. The hydrolysates, when tested at 10 mg/ml, were shown to inhibit tyrosinase by 37–56%. The oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) values of the hydrolysates ranged from 323–494 and 8.9–19.9 μmol trolox equivalents per gram, respectively. The Palmaria palmata hydrolysates inhibited DPP-IV (IC₅₀: 1.60–4.24 mg/mL) and ACE (IC₅₀: 0.14–0.35 mg/mL) activities. The starting protein composition had a significant effect on the tyrosinase inhibitory activity, while protein composition and hydrolytic enzyme preparation had a significant effect on DPP-IV inhibitory and antioxidant activities. In general, the origin of the samples, wild or cultivated, had no effect on the in vitro biological activity of the protein hydrolysates. The results show that Palmaria palmata hydrolysates may have potential applications as health enhancing ingredients and as food preservatives due to their antioxidant and tyrosinase inhibitory effects.     

不同发酵温度和浸渍时间对红葡萄酒理化指标的影响

本文研究了葡萄酒发酵过程中不同发酵温度和浸渍时间对葡萄酒理化指标的影响。温度控制在24～26℃,26～28℃,28～30℃;浸渍时间控制在5d,7d和10d。结果表明,当发酵温度在24～26℃时有利于葡萄酒酒精的转化和色素的浸出;在浸渍时间为7d时有利于对葡萄酒的色素和酚类物质的浸提。因此,发酵温度24～26℃为葡萄酒发酵最适温度;浸渍时间7d为葡萄酒最适浸渍时间。     

Effect of chemical pretreatments on the fermentation and ultimate digestibility of bagasse by Phanerochaete chrysosporium

When sugarcane bagasse was pretreated at room temperature with various chemicals singly or in combination, (0.25 m NaOH; 0.5 m H₂SO₄; 2.6 M NH₃;0.14 M Ca(OH)₂+0.12 M Na₂CO₃;4.2 m EDA; and 0.5 M H₂SO₄ or 0.25 M NaOH followed by 4.2 M EDA), increases in in-vitro digestibility range from 28.9 to 48.6% depending on the particular chemicals. With most pretreatments, the hemicellulose content decreased and the cellulose content increased slightly, while lignin levels decreased only with NaOH + EDA pretreatments. Further fermentation of the chemically pretreated bagasse with Phanerochaete chrysosporium gave increased digestibilities, the highest final digestibility (59%) being achieved by pre-treatment with 0.25 M NaOH. Pretreatment with NaOH or Ca(OH)₂+Na₂CO₃ and fermentation gave greatly increased levels of hemi-cellulose and cellulose and substantial decreases in lignin levels. Chemical pretreatments of bagasse together with autoclaving considerably enhanced in-vitro digestibility (up to 75%) and lignin degradation (1.4%). Pretreatment with NaOH, Ca(OH)₂+Na₂CO₃, and EDA plus autoclaving gave large increases in total hemicelluloses and cellulose and marked decreases in lignin. Further fermentation with P. chrysosporium gave only slight increases in digestibility.     

半干红杨梅果酒复合酵母菌发酵工艺

含酸量较高的杨梅原汁比较适合酿造半干红型的杨梅果酒。葡萄酒酿酒活性干酵母可用作主发酵菌种,适宜接种量为0.3%,但酒色偏淡,原有天然芳香物质损失较大。以0.3%葡萄酒酿酒酵母为主发酵菌种,配合0.1%生香酵母或酿酒高活性酵母可在一定程度上改善酒质,其中生香酵母有提高酒香、酒色和缩短发酵时间的作用;而酿酒高活性酵母对缩短发酵时间和提高酒色效果明显。杨梅果酒不宜采用较高的陈酿温度,最好低于40℃。     

Functional properties of curry paste in relation to digestibility and fermentation by gut microbiota

The prebiotic properties of sour curry paste in the upper gut and the gut microbiota were investigated in vivo during digestion. The effect of the addition of garcinia as souring agent in curry paste was studied. Curry paste without garcinia (P1) and curry paste with garcinia (P2) increased the number of beneficial bacteria in the gut microbiota, especially bifidobacteria and lactobacilli, and significantly (p < 0.05) decreased the number of harmful bacteria (Clostridia). Fecal fermentation with P1 resulted in a prebiotic index (PI) of 1.19, whereas fermentation with P2 resulted in a PI of 2.75. The fermented metabolites produced were lactic acid; vitamins; and short-chain fatty acids (SCFAs) such as acetic acid, propionic acid, and butyric acid. P1 produced metabolites including lactic acid, SCFAs, and B vitamins in higher amounts than P2. After a 24 h fermentation period with colonic microbiota, P1 produced vitamins B1 (18.38 ± 0.10 µg/ml) and B2 (45.28 ± 2.02 µg/ml) but not folic acid, whereas P2 produced only vitamin B1 (5.99 ± 0.48 µg/ml).     

高功率超声波对蛋白质功能特性的影响及其在肉品加工中的应用研究进展

目前,超声波处理在肉品加工前处理及热加工中得到广泛的研究和应用,研究普遍认为超声波的空化效应、机械效应和热效应是引起肉品品质改变的主要原因。本文综述了超声波技术在肉品加工中的技术原理及其在肉品加工前处理和热加工过程中的应用进展,阐述了超声波辅助加工过程中对肉类嫩度、色泽、保水性及脂质、蛋白质氧化的改善效果,并对其应用前景进行展望。总体而言,超声波技术在辅助冻结、解冻、腌制、热加工中对肉类理化性质及感官品质具有显著改善作用。本文为超声波技术在肉品加工中的应用提供了理论参考。     

发酵法制备罗非鱼皮胶原蛋白肽的工艺的研究

目的:研究利用枯草芽孢杆菌进行发酵法生产罗非鱼皮胶原蛋白肽的制备工艺。方法:以罗非鱼皮和水为原料,接入枯草芽孢杆菌进行发酵,对罗非鱼鱼皮浓度、装液量、接种时间、接种量、发酵时间进行了考察,通过单因子实验和正交实验优化确定了最佳发酵工艺。结果:最佳发酵工艺为:罗非鱼鱼皮含量为3%,装液量为90mL/250mL,接种量为5%,接种时间为14h,发酵时间为52h。并且在此发酵工艺下,罗非鱼鱼皮蛋白的水解度高达36.88%。结论:采用枯草芽孢杆菌发酵法制备罗非鱼皮胶原蛋白肽,工艺简单、成本低、不污染环境、水解度高,是值得推广的制备胶原蛋白肽的方法。     

Chemical and physical modification of proteins by the hydroxide ion

Proteins are exposed to alkaline conditions during solubilization and/or purification, during food storage and processing, in removal of toxic constituents, and for characterization. During alkali treatment, there are changes in solubility and aggregation, hydrolysis, elimination reactions involving the side chains of certain amino acids, racemization of amino acid residues, addition of compounds to proteins, fragmentation of the peptide chain, as well as modification or elimination of nonprotein constituents. The rates of these reactions are affected by pH, temperature, cations (in some cases), ionic strength (in some cases), protein concentration, and to some extent by the specific nature of the protein. The general mechanisms and stoichiometry of these reactions are described. Other constituents of high protein foods also undergo reactions in alkaline solutions and the products of these reactions may in turn react with proteins. We have described the effect of alkali on enediol formation and fragmentation of carbohydrates, the hydrolysis of lipids in alkaline solution and effect on rate of peroxidation of the polyunsaturated fatty acids, the oxidation of amino acid residues, especially methionine, the oxidation of phenols to benzoquinones, and the catalytic effect of metal ions in alkaline solutions. Alkali treatment is also used in the specific modification of proteins to distinguish between O-glycosyl and amide-linked glycosyl groups, to effect specific cleavage of peptide bonds via beta elimination, in the formation of anhydrotrypsin, anhydrochymotrypsin, anhydrosubtilisin and thiol-subtilisin, and in formation of intrachain crosslinking in proteins.     

Formation of pyranoanthocyanins by Schizosaccharomyces pombe during the fermentation of red must

Schizosaccharomyces pombe is a non-Saccharomyces yeast strain that can ferment grape musts with high sugar contents - but it also has other metabolic and physiological properties that render it of great interest to wine biotechnologists. This work compares the production of pyranoanthocyanins by S. pombe, Saccharomyces cerevisiae and Saccharomyces uvarum during fermentation. Total pyranoanthocyanins ranged from 11.9 to 19.4mg/l depending on the strain of S. pombe used. On average, S. pombe produced more pyruvic acid than did either Saccharomyces species; as a consequence it also formed more vitisin A-type pigments. S. pombe 938 produced the largest quantity of vitisin A (11.03±0.82mg/l). The formation of large amounts of pyranoanthocyanins intensifies the post-fermentation colour of wines somewhat, a phenomenon that helps them maintain their colour over ageing as the natural grape anthocyanins become degraded. Some of the S. pombe strains showed hydroxycinnamate decarboxylase activity, which favours the formation of vinylphenolic pyranoanthocyanins. Fermentation with S. pombe therefore provides an interesting way of increasing the overall pyranoanthocyanin content of red wines, and of stabilising their colour during ageing.     

微生物发酵提高花生粕营养价值的初步研究

通过蛋白浓缩、氨基酸平衡、大分子蛋白的降解和有益代谢物的积累等指标考察微生物发酵对花生粕营养价值的改善情况。研究发现,采用干酪乳杆菌JD-17和马克斯克鲁维酵母JD-16进行花生粕的生物技术处理,发酵后的花生粕气味酸甜芳香,具有良好的适口性,粗蛋白从48.2%提高到52.8%,赖氨酸、蛋氨酸和总氨基酸的含量也相应提高,分别提高了15.6%、28.2%和18.3%,大分子蛋白明显降解成小分子蛋白,并积累了有益的代谢产物(乳酸含量达到了2.3%)。     

红枣发酵复合茶饮料的研制

以红枣、乌龙茶为主要原料，配以稳定剂等辅助料，经发酵、杀菌等处理，制成一种口感细腻、气味纯和、酸甜适口，且有保健功能的饮料。     

A meta-analysis of variability in continuous-culture ruminal fermentation and digestibility data

A meta-analysis was conducted to compare ruminal fermentation and digestibility data and variability between continuous-culture (CC) experiments and in vivo data. One hundred eighty CC studies representing 1,074 individual treatments, published in refereed journals between 1980 and 2010 were used in this analysis. Studies were classified into 2 groups based on the type of CC used: CC systems specified as rumen simulation techniques (RUSITEC) and non-RUSITEC CC systems (non-RUSITEC). The latter was a diverse group of systems, all of which were termed CC by the investigators. The CC data were compared with a data set of in vivo trials with ruminally cannulated lactating dairy cows (data from a total of 366 individual cows). The reported neutral detergent fiber (NDF) concentration of the diets fed in the 3 data sets was, on average (dry matter basis), 44, 34, and 32%, respectively. The average total volatile fatty acid (VFA) concentration for the RUSITEC and non-RUSITEC data sets was 67 and 80% (respectively) of the total VFA concentration in vivo. The average concentration of acetate was also lower for the CC data sets compared with in vivo and that of propionate was considerably lower for RUSITEC compared with in vivo, but butyrate concentrations were similar between the CC and in vivo data sets. Variability in the VFA data was generally the highest (higher coefficients of variation and variance) for the non-RUSITEC data set, followed by RUSITEC, and was the lowest for in vivo. Digestibilities of NDF and particularly organic matter were lower in the CC data sets compared with in vivo; the average NDF digestibility was 34.2, 45.5, and 53.0% for RUSITEC, non-RUSITEC, and in vivo, respectively. Variability in nutrient digestibility data followed the pattern of variability of the VFA data: highest variability for the non-RUSITEC data set, followed by RUSITEC, and the lowest for in vivo. This analysis showed that CC systems are generally characterized by lower total VFA and acetate concentrations, extremely low counts or lack of ruminal protozoa, and lower organic matter and NDF digestibilities than in vivo. Overall, variability was much greater for CC than for in vivo experimental data.     

利用发酵提高海带饲料的营养价值

试验以海带为主要原料,以琼氏不动杆菌和产朊假丝酵母菌组成的混合菌种为发酵菌种,研究了不同培养基、发酵条件对海带发酵产物中粗蛋白含量和褐藻胶剩余量的影响.结果表明,添加麸皮4%、尿素0.4%、K2HPO4·3H2O 0.3%、MgSO4·7H2O 0.15%、初始pH值为7.0、摇床转速180r/min时,发酵产物中褐藻胶剩余量由1.71%降低为0.88%,粗蛋白含量由1.21%提高为5.63%.     

红枣大麦复合发酵生产新型保健醋

以红枣和大麦为主要原料,麦芽粉先经过糊化、糖化制备麦芽汁与红枣浸提汁复合后,经过酒精发酵、醋酸发酵后加料密封陈酿,经过调配制备新型复合醋.通过红枣与麦芽复合,果粮发酵弥补单一以粮发酵,或单一以果发酵的各项缺点,大麦成本低廉是酿造制品的主要原料,红枣营养丰富口感较甜,糖分很高易于发酵,综合两者优点进行复合发酵得到醇香浓郁的酸甜复合醋.测定试验结果表明:红枣和麦芽复合厚,可以弥补单一以粮发酵醋的香甜口感,并添加了红枣的多种生物活性功能,同时得到一种新型保健发酵醋饮,无论在口感、营养保健方面都符合大众需求,介绍了该产品的生产工艺和操作要点,并配合两种酵母酒精发酵,增添独特口感,制备新型醋饮.