几种多酚类物质用于延长花生牛轧糖货架期的对比研究

通过测定55 ℃和45 ℃2个加速破坏温度条件下花生牛轧糖的过氧化值、酸价、菌落总数、大肠菌群4个指标,对比研究苹果多酚、葡萄籽多酚、茶多酚3种天然酚类物质对花生牛轧糖货架期的影响.结果 表明,添加0.04％的3种酚类物质都具有减缓花生牛轧糖过氧化值升高,抑制花生牛轧糖酸价增高,抑制菌落总数和大肠菌群增加的作用;在花生...     

Storage stability of a high dietary fibre powder from orange by-products

The goal of this investigation was to evaluate the effects of storage time and conditions on the physicochemical and microbiological properties of a high dietary fibre powder (HDFP). HDFP for this study was manufactured from orange juice industry by-products. The storage period was 11 months and samples were stored under vacuum or air exposure and under dark or light exposure. The HDFP is a stable product (based on chemical, microbiological and physicochemical properties) with large amounts of dietary fibre (71.62 ± 0.24 g 100 g⁻¹ dry sample) and polyphenols content (40.67 ± 0.45 mg g⁻¹ dry sample). Hesperidin is the major compound identified in HDFP (higher than 50% of total phenolic compounds). The packaging material used protects the HDFP only up to 6 months. After this time, the increase in moisture content decreases the quality of the product. The best storage conditions are packaging under vacuum and darkness. Both conditions preserve the colour of the fibres probably by means of avoiding pigment degradation.     

杏仁皮单宁提取工艺优化及其DPPH自由基清除活性

以杏仁皮单宁得率为指标,考察了料液比、提取时间、提取温度、乙醇体积分数四个因素对杏仁皮单宁提取效果的影响。在单因素基础上,采用响应面法优化杏仁皮单宁提取工艺,并对最佳工艺下所得杏仁皮单宁的DPPH自由基清除活性进行测试。结果表明:所建立的杏仁皮单宁提取工艺模型极显著,其最优实验条件是料液比1:22 (g/mL)、提取时间89 min、提取温度70 ℃、乙醇体积分数50%,在此条件下杏仁皮单宁得率为2.13%。杏仁皮单宁浓度为250 μg/mL时对DPPH自由基的清除率达到98.65%,表明杏仁皮单宁具有较强的抗氧化活性。     

花生红衣中多酚的研究进展

多酚作为一种生物活性成分,对它的分离提取、结构和功能的研究由来已久。文中对花生红农多酚的测定方法、提取、分离纯化,以及抗氧化和抑菌活性等做了论述。     

Tannins and Human Health: A Review

Tannins (commonly referred to as tannic acid) are water-soluble polyphenols that are present in many plant foods. They have been reported to be responsible for decreases in feed intake, growth rate, feed efficiency, net metabolizable energy, and protein digestibility in experimental animals. Therefore, foods rich in tannins are considered to be of low nutritional value. However, recent findings indicate that the major effect of tannins was not due to their inhibition on food consumption or digestion but rather the decreased efficiency in converting the absorbed nutrients to new body substances. Incidences of certain cancers, such as esophageal cancer, have been reported to be related to consumption of tannins-rich foods such as betel nuts and herbal teas, suggesting that tannins might be carcinogenic. However, other reports indicated that the carcinogenic acitivity of tannins might be related to components associated with tannins rather than tannins themselves. Interestingly, many reports indicated negative association between tea consumption and incidences of cancers. Tea polyphenols and many tannin components were suggested to be anticarcinogenic. Many tannin molecules have also been shown to reduce the mutagenic activity of a number of mutagens. Many carcinogens and/or mutagens produce oxygen-free radicals for interaction with cellular macromolecules. The anticarcinogenic and antimutagenic potentials of tannins may be related to their antioxidative property, which is important in protecting cellular oxidative damage, including lipid peroxidaton. The generation of superoxide radicals was reported to be inhibited by tannins and related compounds. The antimicrobial activities of tannins are well documented. The growth of many fungi, yeasts, bacteria, and viruses was inhibited by tannins. We have also found that tannic acid and propyl gallate, but not gallic acid, were inhibitory to foodborne bacteria, aquatic bacteria, and off-flavor-producing microorganisms. Their antimicrobial properties seemed to be associated with the hydrolysis of ester linkage between gallic acid and polyols hydrolyzed after ripening of many edible fruits. Tannins in these fruits thus serve as a natural defense mechanism against microbial infections. The antimicrobial property of tannic acid can also be used in food processing to increase the shelf-life of certain foods, such as catfish fillets. Tannins have also been reported to exert other physiological effects, such as to accelerate blood clotting, reduce blood pressure, decrease the serum lipid level, produce liver necrosis, and modulate immunoresponses. The dosage and kind of tannins are critical to these effects. The aim of this review is to summarize and analyze the vast and sometimes conflicting literature on tannins and to provide as accurately as possible the needed information for assessment of the overall effects of tannins on human health.     

茶多酚对冷藏带鱼品质及抗氧化效果的影响

以带鱼为研究对象,采用不同质量浓度（0、0.10、0.15、0.20、0.25、0.30、0.40 g/100 mL）茶多酚将带鱼片浸渍30 min后于4 ℃冷藏,每隔3 d取样测定菌落总数以及酸价、过氧化值（peroxide value,POV）、硫代巴比妥酸（thiobarbituric acid,TBA）值、三甲胺（trimethylamine,TMA）值、挥发性盐基氮（total volatile basicnitrogen,TVB-N）值等理化指标和感官评分、色差、质构分析,研究不同质量浓度茶多酚对带鱼的抗氧化效果。结果表明：带鱼的菌落总数、酸价、POV、TBA值、TMA值、TVB-N值以及颜色饱和度值都随贮藏时间延长而呈现增加的趋势,感官评分及质构测得的各项参数一直降低。经茶多酚处理过的实验组各项指标相对空白对照组变化较为缓慢,且当茶多酚质量浓度为0.20 g/100 mL时,保鲜效果最佳,能够抑制带鱼低温冷藏过程中的细菌生长,并有效减缓蛋白质、脂肪等氧化分解,不仅使带鱼货架期延长了3 d,而且使带鱼的色泽与营养在更长的保存时间内保持不变。     

植物多酚生物利用度及提高方法研究进展

植物多酚与人类健康关系密切,然而其在体内的生物活性受到生物利用度的影响和制约。作者从植物多酚在体内的吸收、代谢、运转过程出发,综述了影响多酚口服生物利用度的因素和现阶段提高多酚口服生物利用度的方法,明确了植物多酚口服生物利用度的研究方向。     

海藻多酚的生物活性研究进展

海藻多酚是一类广泛存在于藻类体内的具有多元酚结构的次生代谢物,分子量分布范围复杂,是间苯三酚衍生物.由于我国海藻资源丰富,近年来,从海藻中提取的活性物质-海藻多酚逐渐进入人们的视野.随着对海藻多酚研究的深入,其独特的生物活性日益受到人们的关注.海藻多酚结构复杂,具有广泛的生物活性,对开发海洋保健食品、海洋药物具有重要意...     

植物多酚对肉制品蛋白氧化的抑制机理及其延长货架期的应用

蛋白氧化和微生物污染是导致肉与肉制品在贮藏期间腐败变质的主要因素。植物多酚具有良好的抗氧化和抑菌活性,在肉与肉制品中添加植物多酚是防止其变质的有效方法之一。本文综述了植物多酚的种类及其对肉与肉制品蛋白质氧化和微生物污染的抑制机理;介绍了多酚以作为反应性物质清除剂、非自由基衍生物清除剂、过渡金属离子螯合剂和高铁肌红蛋白还原剂4 种方式抑制蛋白氧化,并通过与细菌细胞壁组分和细胞膜相互作用、防止和抑制生物膜形成、合成生物大分子及抑制细菌酶活性来延长肉与肉制品货架期;此外,还阐述了植物多酚在抑制肉制品氧化及微生物方面的应用,并对其研究前景进行了展望。     

加速破坏性试验确定核桃糕的保质期

为预测核桃糕的保质期,以感官、酸价、过氧化值、菌落总数、霉菌等为评价指标,采用加速破坏性试验,在37℃和47℃的条件下进行试验.根据加速破坏性试验(ASLT),θs(T)=θs (T')=Q10△Tα/10,计算出常温(25℃)下核桃糕的保质期.结果 表明:采用KOPP21U/CPP30U包装材质包装的核桃糕的Q10=...     

Chemical and sensory analyses of spray- and freezedried extracts of rooibos tea (Aspalathus linearis)

Spray- and freeze-dried rooibos tea extracts were prepared, and the soluble solids which precipitated upon cooling of the concentrate were isolated. Their effect on composition and sensory qualities of the dried tea was determined. Preparation of soluble rooibos teas resulted in significant flavour differences, but no preference for freshly brewed tea was found. The method of dehydration and removal of precipitated solids did not affect the flavour of the dried tea extract significantly. Removal of the precipitate resulted in marked decreases in total polyphenol, flavonoid, tannin, flavanol and proanthocyanidin content of the dried soluble product.     

茶多酚微胶囊的理化特性及其在油脂中的抗氧化性能

为了提高茶多酚在油脂体系中的利用度,以辛烯基琥珀酸淀粉钠为壁材,通过喷雾干燥法制备茶多酚微胶囊。对茶多酚微胶囊的形貌特征、粒度分布、溶解度和热稳定性进行分析,并将其应用于大豆油中,通过测定加速氧化过程中的全氧化值进行货架期预测。结果表明：茶多酚微胶囊颗粒粒径分布均匀,球体表面凹陷,热稳定性好;在25 ℃下,添加200 mg/kg茶多酚微胶囊的大豆油货架期可以延长至249.89 d,与未添加茶多酚微胶囊的大豆油相比货架期延长了79 d。     

玉米多酚提取工艺及其生物活性研究进展

玉米多酚是从玉米生产或加工的副产品中提取的一种生物活性成分,具有抗氧化和抑菌活性,在功能食品、保健品以及医药等领域具有潜在的应用价值,以近年来国内发表的文献为依据,总结概述了玉米多酚的提取工艺及其生物活性研究进展,并指出存在问题,展望其研究方向,为玉米多酚的深入研究及开发利用提供了参考依据.