茶多酚对不同结构淀粉血糖反应的影响

目的:研究茶多酚对三种不同结构的淀粉所引起血糖反应的影响。方法:分别以糯玉米淀粉、普通玉米淀粉、高直链淀粉与茶多酚的混合物灌胃小鼠,观察其血糖变化情况。同时体外模拟淀粉消化,研究茶多酚对不同淀粉消化性的影响。结果:以不同淀粉灌胃小鼠,茶多酚对其血糖反应影响不同。对糯玉米淀粉和普通玉米淀粉引起的餐后血糖反应具有降低效果,而在一定程度上提高了高直链玉米淀粉引起的血糖反应。体外实验观察到了同样结果,且抑制效果与茶多酚浓度相关。结论:茶多酚对不同种类的玉米淀粉引起的血糖反应具有不同影响,对糖尿病防治具有积极意义。      

玉米多孔淀粉对茶多酚的吸附性能研究

采用α-淀粉酶与葡萄糖淀粉酶水解玉米淀粉制备多孔淀粉,扫描电子显微镜观察发现其表面具有独特的多孔结构,并向内部延伸,比表面积增大,说明多孔淀粉可以作为良好的吸附载体。研究探讨了玉米多孔淀粉作为载体吸附茶多酚的性能,确定了多孔淀粉吸附茶多酚的最佳条件为茶多酚初始浓度4mg/mL、温度20℃、吸附时间60min、pH值为7,在此条件下,多孔淀粉对茶多酚的吸附达到饱和,最大吸附量达到68.65mg/g,比原淀粉提高了2.1倍。     

茶多酚对淀粉消化酶动力学的影响

研究茶多酚对淀粉酶动力学以及对淀粉体外消化的影响,结果表明,茶多酚对猪胰α-淀粉酶的抑制作用属于非竞争性抑制,对淀粉葡萄糖苷酶具有明显的促进作用;在茶多酚浓度低于20%（茶多酚/淀粉）时,对Englyst法混酶体系起抑制作用,最大抑制率可达30%,浓度超过20%时,对混酶反而起促进作用,最大促进率为20%;选取两个浓度研究茶多酚对普通玉米淀粉体外消化的影响,添加10%茶多酚（茶多酚/淀粉）抑制普通玉米淀粉的消化,25%茶多酚（茶多酚/淀粉）促进普通玉米淀粉的消化,证明茶多酚对淀粉消化性体外测定方法的准确性存在影响。      

淀粉微胶囊对茶多酚的载运及其对餐后血糖反应的影响

为了保护茶多酚及实现其在小肠上半段的定点释放,实验以轻度糊化玉米淀粉吸附茶多酚,再将其包埋入海藻酸钠和氯化钙、壳聚糖组成的外壁里,得到载运茶多酚的淀粉微胶囊。最好的工艺为1.5 g轻度糊化玉米淀粉,20 mL 25 mg/mL的茶多酚,10 mL 0.25%的海藻酸钠,25mL 0.1%的壳聚糖,25 mL 1.0%的氯化钙,pH3.5制备的微胶囊包埋率可达84.08%,平均包载量达207.6 mg/g。体外模拟胃肠道实验及小鼠实验均验证了微胶囊实现了对茶多酚的保护及释控,小鼠餐后血糖整体趋势相对平缓,峰值减小且延后。     

焙烤过程对红茶面包淀粉消化特性的影响及其机理研究

研究了焙烤过程对红茶面包淀粉消化特性的影响,并通过茶多酚HPLC分析、茶色素含量测定及酶活抑制实验,对其机理进行了探究。结果表明:在不同焙烤条件下,红茶面包的淀粉消化特性不同,当焙烤条件设定为190℃、15 min时,其葡萄糖释放速率最为缓慢;经焙烤之后,红茶中的儿茶素含量未发生明显变化,茶黄素、茶红素、茶褐素含量均降低,但低极性茶多酚含量增加;红茶经焙烤后,其水提物对α-淀粉酶活力和α-葡萄糖苷酶活力的抑制效果均增强。低极性茶多酚的生成受焙烤过程的影响,其对淀粉消化酶的抑制显著,进而降低红茶面包的淀粉消化速率,因而,焙烤条件是开发低血糖生成指数(GI)焙烤食品的关键因素。     

不同烹调方式淀粉食材的血糖反应和饱腹感反应

为了解食物制备方法对血糖指数(GI)和饱腹感的影响,在健康受试者中测定预先浸泡的山药干、薏米、芡实、莲子和红小豆经常压蒸煮、压力烹调和焙烤打粉冲糊3种处理后的GI值和餐后2 h饱腹感指数(SI).结果表明:山药干、薏米、芡实、莲子和红小豆常压烹调后的GI值分别为106,81,74,41和23,压力烹调后分别为130,8...     

不同酶制备木薯抗性淀粉的性质比较

以木薯淀粉为原料,用耐高温α-淀粉酶和普鲁兰酶分别制备了RS3型抗性淀粉,并对其直链淀粉含量、冻融稳定性、持水性进行测定与比较。结果表明,α-淀粉酶制备抗性淀粉含量在9.4%～12.4%之间,直链淀粉含量随着酶解作用降低,且直链淀粉含量高的抗性淀粉其冻融稳定性略低,持水性保持在3.7～5.8g/g之间波动不明显。普鲁兰酶制备抗性淀粉含量在4%～7.9%之间,直链淀粉含量不一定随着酶解作用而增加,且直链淀粉含量高的抗性淀粉其冻融稳定性和持水性高。耐高温α-淀粉酶制备的木薯抗性淀粉含量、冻融稳定性高于普鲁兰酶,对直链淀粉含量的影响较直观,但持水性低于普鲁兰酶。      

酶催化水解对马铃薯淀粉结构的影响

颗粒状马铃薯淀粉经α-淀粉酶催化水解后,检测了水解清液中的还原糖含量,并应用SEM、X-射线衍射和热失重(TG)对产品进行了分析,结果表明,α-淀粉酶催化水解马铃薯淀粉时,其收率与酶的浓度和反应时间成反比,而溶液中糖含量与反应时间则成正比的关系;颗粒状马铃薯淀粉不易进行酶的催化水解反应,且α-淀粉酶只能腐蚀淀粉颗粒的表面,酶催化水解不能提高淀粉颗粒的结晶度;酶解时间较长时,产品的热稳定性降低.     

酶催化水解对玉米淀粉结构的影响研究

颗粒状玉米淀粉经α-淀粉酶催化水解后,应用SEM、X射线衍射和热失重(TG)对产品进行了分析.检测结果表明,α-淀粉酶催化水解玉米淀粉时,其收率与酶的浓度和反应时间成反比;颗粒状玉米淀粉发生酶催化水解时,α-淀粉酶首先使淀粉形成多孔状结构,并进一步使颗粒破裂,断裂的颗粒碎片上显示出淀粉颗粒内部具有层状的生长环结构;酶催化水解不能提高玉米淀粉颗粒的结晶度;酶解时间较长时,产品的热稳定性降低.     

淀粉分子结构与α-淀粉酶酶解性能的相关性

以6种不同来源的淀粉为研究对象,分析了淀粉分子结构对其α-淀粉酶酶解性能的影响。结果表明,α-淀粉酶酶解直链淀粉的效率要低于支链淀粉,且直链淀粉含量并非导致淀粉酶解性能差异的主要因素;支链淀粉的链长分布对α-淀粉酶酶解效率有较大影响,其平均链长与α-淀粉酶酶解效率的线性相关性显著。     

Influence of polyphenol oxidase activity and polyphenol content of tea shoot on quality of black tea

Variation in polyphenot oxidase activity and levels of total polyphenols and catechins with respect to different clones and shoot components, and its effect on quality of black tea (Camellia sinensis (L) 0 Kuntze, were studied. There was a wide variation in polyphenol oxidase activity of the different clones tested. The optimum fermentation time and polyphenol oxidase activity of different clones exhibited a hyperbolic relationship, viz y = 2.36 + 1129/x, where y = optimum fermentation time in minutes and x = polyphenol oxidase activity in μM catechol oxidised g^?1 acetone powder min^?1, with an r value of ?0.98, which is signi Jicant at P ≤ 0.001. A good non-linear relationship was found between polyphenol oxidase activity of ji-esh tea shoots of different clones and the theajavins content of corresponding black teas. Among different shoot components, bud and first leaf had higher levels of polyphenols and catechins than internodes. However, the polyphenol oxidase activity showed a reverse trend: the internodes exhibited a higher enzyme activity compared with other components. Formation of theajavins during fermentation of different shoot components was in good agreement with polyphenol oxidase activity. High performance liquid chromatographic analysis of the theaflavins fraction in tea brew of black teas made from different components of tea shoot showed that buds resulted in black tea with the highest amount of theaflavin gallates, whereas teas produced from internodes had the lowest amount of theaflavin gallates. A new factor, viz theaflavin digallate equivalent, was developed, and the significance of this factor for chemical evaluation of black tea quality is discussed in this paper.     

茶多酚水溶液浸提法生产低咖啡碱茶叶的研究

首次采用茶多酚水溶液浸提法脱除鲜茶叶与干茶叶中的咖啡碱,并保留其中的主要功能性成分茶多酚。鲜茶叶最佳浸提条件为:温度100℃,料液比1:10(g/mL),茶多酚水溶液质量体积分数5%,时间5min。此条件下咖啡碱脱除率达80.61%,比传统热水浸提法提高31.25%,且茶多酚无损失。干茶叶最佳浸提条件为:温度100℃,料液比1:20(g/mL),茶多酚水溶液质量体积分数15%,时间7min。此条件下咖啡碱脱除率达81.61%,且处理后的茶叶中茶多酚含量提高90.02%。研究结果表明,针对鲜茶叶和干茶叶原料,茶多酚水溶液浸提法均能有效脱除其咖啡碱,并有效保留或提高茶叶中的茶多酚,比传统热水浸提法有明显优势,是一种生产低咖啡碱茶叶的新方法。     

茶多酚在棉织物上的抗菌整理研究

研究了茶叶主成分茶多酚在棉织物上的抗菌效果,试验了硫酸铝钾用量、茶多酚用量、pH值、温度、时间和水洗次数对棉织物抑菌性的影响.结果表明:经茶多酚处理后棉织物具有较好的抑菌效果.在硫酸铝钾10%(owf)、茶多酚6 g/L、pH值6.88、50℃、60 min条件下整理的棉织物,对金黄色葡萄球菌、大肠杆菌的抑菌率较高,水洗30次后对金黄色葡萄球菌、大肠杆菌的抑菌率仍可保持在70%以上.     

Influence of atmospheric pressure plasma jet on the structure of microcrystalline starch with different relative crystallinity

This study demonstrated the effect on microcrystalline starch (MS) with different relative crystallinity (RC) by atmospheric pressure plasma jet (APPJ) treatment for 1, 3, 5 or 7 min. The morphology of MS granules was destroyed according to Scanning electron microscopy (SEM) analysis. APPJ treatment did not change the crystalline type of MS, but obviously decreased the RC of MS. Short-range molecular order of MS was clearly decreased after APPJ treatment though the Fourier transform infrared (FTIR) and Raman spectroscopy. Notably, the effect of APPJ on crystalline and short-range order structure of MS was gradually increased with the increase of RC, which revealed that the crystalline region of MS might be destroyed by APPJ. Furthermore, the pH of MS was decreased while water binding capacity (WBC) and swelling volume (SV) of MS were increased. Therefore, the APPJ treatment could be used as an alternative physical technology for starch modification.     

Changes of trypsin in activity and secondary structure induced by complex with trypsin inhibitors and tea polyphenol

To reveal the relationships between the activity of trypsin and its structural change, changes of trypsin in biological activity induced by complex with Bowman-Birk trypsin inhibitor (BBTI), Kunitz soybean trypsin inhibitor (KSTI, type I-S) and tea polyphenol (TP) were detected and their relationship with the secondary structure changes were studied by far-UV circular dichroism (CD) spectra measurement. BBTI and KSTI were also irradiated by ultrasonic to compare the effects on trypsin. The rank was found as KSTI > BBTI > TP according to their inhibitory activities against trypsin. Yet BBTI exhibited much stronger resistance against ultrasonic irradiation than KSTI. BBTI, KSTI and TP were found inactivate trypsin by modifying the secondary structures and far-UV spectrum of trypsin. Complex of trypsin with ultrasonic-treated BBTI and native BBTI and KSTI exhibited the similar modified effects in secondary structures, decrease of α-helix and β-turn content, increase of β-sheet content and unchanged random coil content basically. But complex of trypsin with ultrasonic-treated KSTI exhibited less modified effects because of inactivation by ultrasonic irradiation. The changes of trypsin in secondary structure induced by complex with TP showed different from those induced by complex with BBTI and KSTI, increase of α-helix content, decrease of random coil content and unchanged β-sheet and β-turn content basically.     

茶叶中多酚氧化酶提取的响应面优化

优化了茶叶多酚氧化酶的提取工艺,为进一步的纯化提供了理论参数。在单因素试验的基础上,选取了提取缓冲液pH、保护剂添加量、料液比3个因素进行了CCD响应面试验设计,对提取参数进行优化。结果显示,当缓冲液pH为5.6,保护剂PVP添加量为0.16%,料液比为1:4.5时,所得的酶活最高。采用响应面分析,能得到最高的酶活提取条件,并且能较为准确的预测试验结果。     

茶多酚对鱼糜保藏效果的研究

为解决鱼糜易氧化腐败的难题,将天然抗氧化剂茶多酚、茶多酚＋Vc、茶多酚＋Vc＋柠檬酸添加到鱼糜中,通过对冷藏鱼糜的水分含量、凝胶强度、酸价、过氧化值、挥发性盐基氮等因素变化的研究,探讨茶多酚对鱼糜的保鲜效果。结果表明：茶多酚对冷藏鱼糜具有保鲜效果,Vc有一定增效作用．而柠檬酸增效作用不明显。     

多酚物质对啤酒稳定性的影响

多酚物质对啤酒稳定性的影响主要表现在它的氧化还原性及与蛋白质结合能力上,啤酒的混浊主要为多酚及氧化产物与蛋白质的聚合物;所以多酚是影响啤酒的非生物稳定性的主要物质之一。另一方面多酚物质又是构成啤酒风味的主要物质,它具有氧化还原性直接影响啤酒的风味稳定性。提出了合理控制多酚物质的手段。     

茶树花中茶多酚和茶皂素综合提取技术研究

为了实现对茶树的综合利用,以茶树的花为实验材料,在单因素实验的基础上,采用正交实验方法对茶树花中茶多酚和茶皂素的综合提取工艺进行优化。分析了浸提时间、料液比、浸提温度、乙醇浓度和超声波功率对浸出率的影响。结果表明,乙醇浓度70%,超声波功率350W,浸提温度60℃,浸提时间10min,料液比1∶30g/mL时,茶多酚和茶皂素的综合得率最高,分别达到了28.38%和23.69%。     

茶多酚对棉织物的功能整理研究

利用茶多酚对棉织物进行功能整理,探讨其最佳工艺参数及功能整理棉织物性能,得到最佳工艺参数:茶多酚用量为6%(o.w.f.)、整理液温度为50℃、整理时间为60 min、整理液pH值为6～7;在最佳工艺参数条件下,功能整理棉织物的耐日晒色牢度、耐水洗色牢度与耐摩擦色牢度均达4级以上,且其抗菌及防紫外线性能良好。