Polyphenol-Rich Extract of Fenugreek Seeds Protect Erythrocytes from Oxidative Damage

A polyphenol-rich extract from the seeds of fenugreek was evaluated for its protective effect against hydrogen peroxide(H₂O₂)-induced oxidation in normal and diabetic human erythrocytes (RBCs). RBCs, preincubated with increasing amounts of fenugreek seed extract and challenged with H₂O_2, were analyzed for hemolysis and lipid peroxidation. RBCs from diabetic subjects were more susceptible to oxidative hemolysis and lipid peroxidation than those from normal subjects. However preincubation with the polyphenol-rich extract significantly reduced the oxidative modifications in both the groups. The inhibition of lipid peroxidation was concentration-dependent up to 100 l of extract, which contained 0.75mM gallic acid equivalent (GAE) of phenolic compounds. These findings demonstrate the potent antioxidant properties of the fenugreek seeds.     

Effects of heat on the removal of polyphenols and in vitro protein digestibility of cowpea (Vigna unguiculata (L.) Walp.)

Simple wet heat treatments like simple boiling (atmospheric pressure, 100 °C) and pressurized boiling (higher than 100 °C) reduced the polyphenol content of mature dark red seeds of cowpea (Vigna unguiculata (L.) Walp.) cultivar UPL Cp 3 by 61 to 80% and improved in vitro protein digestibility (IVPD) by 6 to 26%. Pressurized steaming (higher than 100 °C) removed 48 to 83% of the polyphenols but increased IVPD by only 1.1 to 4.2%. Dry heat as exemplified by roasting and microwave treatment inactivated 58 to 71% of the tannins but increased IVPD by only 1%. All the heat treatments were effective in removing/inactivating polyphenols though different responses were observed with the resulting in vitro protein digestibilities.     

Effects of heat treatments and germination on trypsin inhibitor activity and polyphenols in jack bean (Canavalia ensiformis L. DC)

The application of dry heat to seeds and meal was not effective in inactivating the TI and reducing the polyphenol content. Soaking for 24 h followed by cooking for 20 min, was equally effective in destroying the TI activity. Germination of jack bean seeds for 40 h decreased the levels of TI and polyphenols by 31% and 35%, respectively.     

采后芦笋多酚类物质变化的研究进展

多酚是植物体内一种次生代谢产物,具有抗氧化、抗菌、抗肿瘤等生物功效,受到食品、营养、医学等领域科技人员的广泛关注和研究。芦笋富含多酚类化合物,是一种珍稀蔬菜,对人类膳食营养和疾病预防具有积极作用。综述了采后芦笋商业分级、多酚类等生物活性物质的变化及其影响因素,以期为芦笋的开发利用和食疗保健研究提供理论参考。     

三种茶叶的抑菌作用研究

为了探究不同种类茶叶的抑菌效果及指导日常饮茶。以苏云金芽孢杆菌和大肠杆菌作为指示菌,采用滤纸片抑菌圈法测定3种茶叶对其的抑菌效果。结果表明,茶叶粗体液的抗菌效果与茶叶浓度呈正相关;3种茶叶的抑菌效果依次为茉莉花茶>铁观音>红茶(滇红);铁观音、茉莉花茶在提取时间为20 min时获得最大提取率,滇红在提取时间为50 min时,抑菌圈直径最大;铁观音分别再80℃和90℃有最大的抑菌效果,而茉莉花茶和滇红的抑菌效果都随提取温度的增加而增加。茶叶粗提物对革兰氏阳性细菌的抑制效果大于革兰氏阴性细菌;铁观音在提取质量浓度为5 mg/m L,提取时间20 min,提取温度80℃时有较好的抑菌效果。     

桦褐孔菌多酚的提取条件优化和抗氧化能力研究

以桦褐孔菌菌核为试验材料,利用超声?微波协同萃取法提取了桦褐孔菌样品中的多酚,采用单因素和多因素试验优化了桦褐孔菌多酚的提取条件,测定了多酚的抗氧化能力。试验结果显示,超声?微波协同萃取法提取桦褐孔菌多酚的优化条件是乙醇体积分数50%、料液比1∶60、微波功率400 W、超声波功率350 W、提取时间240 s,此条件下的多酚提取率为2.943%。该方法提取的多酚具有良好的抗氧化能力,对DPPH自由基清除率的IC₅₀值为9.03 μg/mL,对羟自由基清除率的IC₅₀值为2.03 mg/mL。该方法是一种实用、有效、快速的提取桦褐孔菌多酚的方法。       

超声波协同酶法提取茶多酚工艺的研究

[目的]探讨不同因素对超声波协同酶法提取茶多酚效果的影响,优化茶多酚提取工艺.[方法]为研究超声波-酶法在茶叶中提取茶多酚的应用效果,采用单因素试验和正交试验,考察水浴温度、水浴超声时间、加酶量、茶多酚与纤维素酶的料液比和乙醇浓度对超声波-酶法提取茶多酚的影响,从而优化提取条件与工艺方法.[结果]试验得出,提取时间对茶多酚的提取影响最显著,优化得出最佳工艺条件为:水浴时间40 min,加酶量10 ml,水浴温度60℃,料液比为5∶50 g/ml,pH为5时,茶多酚提取率最高.[结论]超声波-酶法应用于茶叶中茶多酚的提取具有省时、节能、高效等优点.     

光照处理对发芽燕麦中多酚类物质含量及抗氧化活性的影响

【目的】研究光照处理对发芽燕麦中多酚类物质含量及抗氧化活性的影响。【方法】将燕麦籽粒分为光照组和黑暗组,浸泡后分别在光照（光照强度为200 μmol/(m²·s)）和遮光条件下进行发芽,在发芽24,48,72和96 h时取样,提取样品中的游离态和结合态多酚,测定多酚、黄酮含量及肉桂酸、阿魏酸、没食子酸、对香豆酸、咖啡酸这5种主要酚酸的组分变化。测定游离态和结合态多酚提取物的抗氧化活性（ABTS、DPPH自由基清除能力和铁还原能力）,分析游离态和结合态多酚、黄酮含量与3种抗氧化指标间的相关性。【结果】光照处理下发芽燕麦中游离态和结合态多酚、黄酮含量明显高于黑暗组。游离态多酚提取物中,光照组样品中没食子酸、咖啡酸、阿魏酸含量在发芽过程中总体高于黑暗组,对香豆酸和肉桂酸的含量总体低于黑暗组;5种酚酸的总量在发芽前期（发芽24~48 h）光照组略低于黑暗组,发芽后期（发芽72~96 h）显著高于黑暗组。结合态多酚提取物中,除肉桂酸外,其余4种酚酸的含量在发芽过程中均表现为光照组显著高于黑暗组;在发芽过程中,光照组5种酚酸的总量显著高于黑暗组。光照组样品的游离态和结合态多酚提取物的抗氧化活性均显著高于黑暗组。2种处理下,除游离态黄酮外,发芽燕麦中的多酚、结合态黄酮均与其抗氧化活性间存在显著正相关。【结论】光照处理可有效提高发芽燕麦中多酚物质的含量及其抗氧化活性。     

茶多酚在日化产品中的应用

近年来,茶多酚在洗漱用品、护肤品、纺织品等领域的应用日益广泛,茶叶深加工产品的开发与应用促进了茶产业的转型升级。文章介绍了茶多酚在日化产品中的应用、相关功效,在应用时存在的问题和解决办法,为茶叶深加工产品的开发提供参考。     

氟对茶叶品质成分代谢的的影响

通过盆栽试验研究氟了对茶树新梢生长和品质成分含量的影响。适量增加土壤氟水平能提高新梢产量,但在高氟水平下新梢产量明显下降。茶多酚、咖啡碱及儿茶素(EGCG等)的含量随土壤氟水平的增加而逐渐降低,高氟水平下新梢的游离氨基酸含量也显著下降,苯丙氨酸解氨酶(PAL)、谷氨酸合成酶(GOGAT)的活性也随土壤和茶树氟浓度的增加而下降,说明氟可能抑制茶树儿茶素的合成代谢和氮素代谢。上述结果表明,氟对茶树生长和品质成分的影响与氟水平有关,虽然低浓度氟对茶树生长有一定的促进作用,但高浓度氟抑制茶树生长和茶多酚、氨基酸等品质成分的代谢。