竹叶黄酮的生理活性与应用研究

竹叶黄酮是竹叶中的重要活性成分,具有多种医疗功效。本文在阐述竹叶黄酮的主要成分结构的基础上,综述了竹叶黄酮的测定、提取、生理活性以及应用和安全性的研究进展,并对其发展前景作了一定的阐述。     

竹叶花椒黄酮抗氧化性及协同效应研究

目的:研究竹叶花椒黄酮提取物的抗氧化性以及协同效应。方法:采用DPPH自由基、ABTS自由基清除法评价竹叶花椒黄酮提取物的抗氧化活性,并通过加和法研究竹叶花椒黄酮提取物与维生素C和芦丁复配物的协同作用。结果:竹叶花椒黄酮提取物对DPPH自由基和ABTS自由基的半抑制浓度分别为0.03,0.062 mg/mL,具有较强的抗氧化活性。竹叶花椒黄酮提取物与维生素C或芦丁组成的复配物抗氧化活性高,且在复配比例为1∶1时抗氧化性最强,维生素C+黄酮提取物组成的复配物的抗氧化活性较芦丁+黄酮提取物组成的复配物高。结论:竹叶花椒黄酮具有强抗氧化性,其与维生素C及芦丁组成的复配物可提高对DPPH自由基和ABTS自由基的清除能力,具有抗氧化协同作用,可作为天然抗氧化剂的潜在来源。     

竹叶黄酮的生理功能及提取工艺

竹叶黄酮是竹叶的重要活性成分,具有多种医疗功效。现对竹叶黄酮的主要成分,生物学功能、提取工艺及发展前景作一综述。     

竹叶黄酮复方片的降脂实验研究

目的研究以竹叶黄酮为主,与决明子、柚子汁等不同成分优化组合,制备具有抗氧化活性和降脂功能的竹叶黄酮复方产品。方法建立高脂血症大鼠模型,根据总胆固醇水平随机分组,口服灌胃。实验组分别给予相应剂量的竹叶黄酮复方片（复方Ⅰ：竹叶黄酮、决明子、柚子汁和维生素C棕榈酸酯复配;复方Ⅱ：竹叶黄酮、决明子和柚子汁复配）和竹叶黄酮单方片,对照组灌胃相同体积的蒸馏水。实验结束后检测实验大鼠的血清总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）水平和血清总抗氧化活性、超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）活性及肝脏丙二醛（MDA）水平。结果药物干预6周后,竹叶黄酮复方Ⅰ可显著降低高脂血症大鼠血清的TC、TG、LDL—C水平,显著改善大鼠肝脏的脂肪沉积和变性状况;与高脂模型组比,竹叶黄酮复方Ⅰ和Ⅱ的血清总抗氧化能力、血清SOD活性均显著升高、优于竹叶黄酮单方实验组;此外,竹叶黄酮复方Ⅰ降低实验大鼠肝脏MDA水平的作用极显著（P〈0．01）,竹叶黄酮复方Ⅱ作用显著（P〈0．05）。结论竹叶黄酮与决明子和柚子汁复配,并添加维生素C棕榈酸酯后降脂协同增效作用显著,生物利用度提高,降低血脂和预防动脉粥样硬化的功效突出。     

竹叶黄酮的抗氧化活性研究

为了有效利用竹叶中黄酮类物质,研究采用不同的方法(DPPH法、邻苯三酚自氧化法(325nm)和Fenton法)评价了竹叶黄酮的抗氧化活性,以Vc和茶多酚为阳性对照品。结果表明:竹叶黄酮清除超氧负离子自由基和DPPH自由基的能力比茶多酚强,其EC50相应为11.7μg/mL和18.3μg/mL,分别是Vc的约1.2倍和3.4倍;竹叶黄酮在清除羟自由基效果与茶多酚相当,EC50为0.58mg/mL,比Vc效果好。因此竹叶黄酮具有很强的抗氧化能力,值得深入研究其生理功能及开发利用价值。     

竹叶黄酮最新研究进展之一——竹叶黄酮制剂中酚酸类化合物的存在及其作用

竹叶黄酮(Bamboo Leaf Flavonoids,BLF)是一种新型植物黄酮制剂,具有多种优良的生物学功效,而来源于竹叶酚性部位的竹叶抗氧化物(Antioxidant of Bamboo Leaves,AOB)也于2004年列入GB 2760,现允许在很多类食品中作为天然抗氧化剂使用.本文阐述了竹叶黄酮的质量控制及其标准化建设,重点对制剂中酚酸类化合物的含量、作用及其意义进行了阐述,以期为竹叶黄酮在保健食品和膳食补充剂等领域的应用提供指导和依据.     

竹叶黄酮糖苷的水解及其苷元的抗氧化性能研究注--Ⅱ黄酮苷元抗油脂氧化性能的初步评价

本文对竹叶黄酮水解苷元的抗油脂氧化和清除羟基自由基(@OH)活性进行了测试.TBA快速测定法表明,在菜籽油体系中,水解苷元显示了与BHT可比的抗氧化活性,其有效浓度在0.2‰左右;改良烘箱法试验表明,水解苷元抑制猪油过氧化的能力与槲皮素和茶多酚相似;采用Vc-Cu2+-H2O2-酵母多糖体系产生@OH,用化学发光法测定的结果显示,水解苷元的清@OH活性接近槲皮素.表明竹叶黄酮苷元具有作为天然油脂抗氧化剂的开发潜力.     

竹叶黄酮对CCl4所致小鼠肝细胞损伤的保护作用

以研究竹叶黄酮对CCl4所致小鼠肝细胞损伤的保护作用为目的,通过建立CCl4损伤肝细胞模型,观察不同剂量的竹叶黄酮对谷丙转氨酶(ALT)、谷草转氨酶(AST)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)、肝糖元含量的影响,并观察空白对照组、模型组及各剂量组肝组织石蜡切片的病变情况.结果显示,与空白组相比,模型组ALT、AST、MDA显著升高(p＜0.05),肝糖元含量、GSH-Px和SOD活性明显下降(p＜0.05).与模型组比较,在各剂量竹叶黄酮的影响下,ALT、AST和MDA含下降(p＜0.05),GSH-Px、SOD活性和肝糖元含量显著升高(P＜0.05),并呈剂量依赖性,肝组织病变程度明显低于模型组.本实验证明竹叶黄酮对CCl4所致小鼠肝细胞损伤有较好的保护作用.     

竹叶中黄酮和茶多酚的高压脉冲电场提取

采用高压脉冲电场技术,从竹叶中同步提取黄酮和茶多酚活性成分。在单因素试验的基础上,通过正交试验确定高压脉冲电场技术提取竹叶黄酮和茶多酚的最优化工艺。结果表明,竹叶粉与60%乙醇按料液比1∶20胶磨匀质、电场强度22k V/cm、脉冲数为9的条件下进行高压脉冲电场提取,黄酮提取率达到2.49%,茶多酚提取率可达1.26%。该工艺可有效地从竹叶中联合提取黄酮和茶多酚。     

竹叶提取物的研究开发现状

竹叶中含有大量的黄酮、活性多糖、特种氨基酸、芳香成分和微量元素,其提取物是我国新开发的植物类资源,具有优良的抗活性自由基、抗氧化、抗衰老、抗疲劳、增强免疫力、阻断亚硝化反应、抗菌、抑菌等生物学功能.竹叶提取物以其丰富的原料来源、明确的功能因子、良好的食用安全性、高效稳定的制剂品质和清新甜香的竹子风味,近年来在天然功能性食品添加剂、医药保健品、农业工程等领域崭露头角.本文在综述了竹叶提取物的有效成分以及各成分的生理功能的基础上,重点介绍了其抗氧化、清除活性自由基、防腐抗菌的功能以及其在食品生产和农业工程上的应用.此外,本文还比较了各种提取方法的优劣、分析了其主要活性成分的食用安全性和开发利用现状,提出了今后竹叶提取物研究的主要方向.     

虾、蟹壳利用的研究进展

虾、蟹壳是虾、蟹加工过程中产生的主要废弃物,含有较大量的蛋白质、灰分和甲壳素,以及少量的脂肪、游离氨基酸和虾青素等。近年来,随着我国养殖、捕捞技术的进步以及伏季休渔制度的实施,虾、蟹产量逐年上升。因此,有效利用虾、蟹壳副产物,开发基于虾、蟹壳废弃物的利用途径和产品类型,以提高产品附加值,减少环境污染,对于虾、蟹产业的健康发展具有重要意义。目前,采用酸碱法制备甲壳素是虾、蟹壳利用的主要方法,该方法易于操作,但能耗高且污染严重,近年来研究人员对传统的酸碱法制备甲壳素的工艺进行了优化,并积极探索酶法和发酵法等新型提取工艺。此外,虾、蟹壳中其他可利用成分(蛋白质、脂肪、钙质和虾青素)的提取和利用也获得了许多研究成果。本文主要综述了虾、蟹壳的组成成分,虾、蟹壳整体利用途径以及虾、蟹壳中甲壳素、蛋白质、脂肪、钙质、虾青素等成分的提取和利用途径的研究进展,以期为虾、蟹壳的高效、低成本、无污染和高附加值利用提供借鉴。     

Effect of common and new gums on the quality,physical, and textural properties of bakery products: A review

Hydrocolloids (gums) have a good functional characteristic such as emulsifying, gelling, solubility, and textural improvement. In the bakery products, hydrocolloids were used to improving dough performance, bread and cake characteristics, sensorial quality, and extension the products shelf life. Several studies reported the potential use of hydrocolloids in breads, biscuits, cakes, and pasta formulation. The present review summarized the effect of the most common and new hydrocolloids (xanthan, guar, Arabic, carrageenan, karaya, alginate, acacia, methylcellulose, carboxy methyl cellulose, hydroxyl propyl methyl cellulose, locust bean, balangu seed, wild sage seed, basil seed, and cress seed gums) on the rheological, physicochemical, textural, and quality characteristics of bakery products. Gums addition improved volume and porosity of the breads and cakes. Gums influence on the gelatinization and retrogradation of starch and decreased the retrogradation of starch. In the bakery products, hydrocolloids were used to improving mixing and increasing the shelf life of the products through moisture preservation and avoidance of syneresis in some frozen foods. This study summarized the influence of the most common and new hydrocolloids on the rheological, physicochemical, textural, and quality characteristics of bakery products. Addition of seeds gum to the breads, biscuits, cakes, and pasta formula led to an increase in the viscosity of the batter. Also, the firmness of bakery products showed that they became softer with increasing gum levels.     

Starch-based noodles: Current technologies,properties, and challenges

Starch noodles are gaining interest due to the massive popularity of gluten-free foods. Modified starch is generally used for noodle production due to the functional limitations of native starches. Raw materials, methods, key processing steps, additives, cooking, and textural properties determine the quality of starch noodles. The introduction of traditional, novel, and natural chemical additives used in starch noodles and their potential effects also impacts noodle quality. This review summarizes the current knowledge of the native and modified starch as raw materials and key processing steps for the production of starch noodles. Further, this article aimed to comprehensively collate some of the vital information published on the thermal, pasting, cooking, and textural properties of starch noodles. Technological, nutritional, and sensory challenges during the development of starch noodles are well discussed. Due to the increasing demands of consumers for safe food items with a long shelf life, the development of starch noodles and other convenience food products has increased. Also, the incorporation of modified starches overcomes the shortcomings of native starches, such as lack of viscosity and thickening power, retrogradation characteristics, or hydrophobicity. Starch can improve the stability of the dough structure but reduces the strength and resistance to deformation of the dough. Some technological, sensory, and nutritional challenges also impact the production process.     

猕猴桃糖蛋白及其去糖链蛋白功能特性的研究

本文研究了25~60 ℃范围内温度对猕猴桃糖蛋白(CGP)及其去糖链蛋白(GPP)吸油性、溶解性、起泡性和乳化性的影响,以及CGP、GPP的浓度及其溶液pH3~7.5和0~5 g/100 mL范围的NaCl离子强度对CGP和GPP溶解性、起泡性和乳化性的影响。结果表明:25~60 ℃温度范围内CGP吸油性、溶解度高于GPP,随温度升高,CGP、GPP溶解度下降,两者的起泡性先降低后升高,CGP乳化性先降低后升高,GPP乳化性先升高后降低;不同pH条件下,CGP的溶解度始终高于GPP,pH3~6范围内CGP、GPP溶解度均先下降后升高,pH3~7.5范围内CGP、GPP起泡性和乳化性先下降后升高;随离子强度的升高,CGP、GPP溶解度均下降,且CGP的溶解度始终高于GPP,CGP的起泡性和乳化性下降,GPP起泡性先下降后升高而乳化性则相反;CGP、GPP起泡性和乳化性均随其浓度的增高而增高,1.0 mg/mL时起泡性和乳化性最高,0.2 mg/mL时最低。     

纸质文献保存和修复方法专利技术综述

通过对纸质文献保存和修复领域专利技术文献的收集、分析、标引和梳理,分析了该领域专利技术分布及专利申请情况,分别探析了脱酸、修补、加固、装裱4种技术的专利技术演进路线,最后对该领域专利技术进行了总结。     

Fruit and Vegetable Waste: Bioactive Compounds,Their Extraction,and Possible Utilization

Fruits and vegetables are the most utilized commodities among all horticultural crops. They are consumed raw, minimally processed, as well as processed, due to their nutrients and health‐promoting compounds. With the growing population and changing diet habits, the production and processing of horticultural crops, especially fruits and vegetables, have increased very significantly to fulfill the increasing demands. Significant losses and waste in the fresh and processing industries are becoming a serious nutritional, economical, and environmental problem. For example, the United Nations Food and Agriculture Organization (FAO) has estimated that losses and waste in fruits and vegetables are the highest among all types of foods, and may reach up to 60%. The processing operations of fruits and vegetables produce significant wastes of by‐products, which constitute about 25% to 30% of a whole commodity group. The waste is composed mainly of seed, skin, rind, and pomace, containing good sources of potentially valuable bioactive compounds, such as carotenoids, polyphenols, dietary fibers, vitamins, enzymes, and oils, among others. These phytochemicals can be utilized in different industries including the food industry, for the development of functional or enriched foods, the health industry for medicines and pharmaceuticals, and the textile industry, among others. The use of waste for the production of various crucial bioactive components is an important step toward sustainable development. This review describes the types and nature of the waste that originates from fruits and vegetables, the bioactive components in the waste, their extraction techniques, and the potential utilization of the obtained bioactive compounds.     

Content,composition, and stereochemical characterisation of lignans in berries and seeds

In seed extracts of five oilseed species, in bran extracts of three cereal species, and in seed and/or whole berry extracts of 10 berry species, the concentrations of a large number of lignans and the enantiomeric composition of selected lignans were determined. In the case of sesame and hemp seeds, the lignan content and composition of the whole seeds was compared to that of the hulled seeds. The results showed that cloudberry seeds are the third most lignan-rich food source after linseeds and whole sesame seeds, and that most of the berry species analysed were more lignan-rich than the cereal brans. The lignans are concentrated in the hull of the oilseeds and in the seeds of the berries. In most samples, secoisolarici-, pino-, medio-, and syringaresinol were present as a mixture of two enantiomers.     

3种功能性甜味剂对大米蒸煮品质和消化特性的影响

为提高米饭蒸煮品质、延缓米饭回生和改善米饭消化性能,比较不同质量分数低聚果糖、山梨糖醇和麦芽糖醇3 种低能量甜味剂对大米浸泡吸水率、直链淀粉比例、硬度、微观结构、晶体结构、热特性及消化特性等指标的影响。结果表明,3 种甜味剂处理均能够提高大米的吸水率,降低米饭的硬度。此外,低聚果糖、山梨糖醇和麦芽糖醇处理均能降低米饭的体外消化水解率。其中,1.6%低聚果糖处理的大米在浸泡25 min时吸水率提高了11.18%,直链淀粉比例、糊化焓值和放置24 h后硬度分别降低了7.36%、22.91%和21.79%,且与其他处理相比,显著降低了糊化焓值和结晶度,并表现出较好的微观结构和抗回生性。该研究为大米精深加工与方便米饭产品开发提供依据。     

Quality evaluation of fish and other seafood by traditional and nondestructive instrumental methods: Advantages and limitations

Although being one of the most vulnerable and perishable products, fish and other seafoods provide a wide range of health-promoting compounds. Recently, the growing interest of consumers in food quality and safety issues has contributed to the increasing demand for sensitive and rapid analytical technologies. Several traditional physicochemical, textural, sensory, and electrical methods have been used to evaluate freshness and authentication of fish and other seafood products. Despite the importance of these standard methods, they are expensive and time-consuming, and often susceptible to large sources of variation. Recently, spectroscopic methods and other emerging techniques have shown great potential due to speed of analysis, minimal sample preparation, high repeatability, low cost, and, most of all, the fact that these techniques are noninvasive and nondestructive and, therefore, could be applied to any online monitoring system. This review describes firstly and briefly the basic principles of multivariate data analysis, followed by the most commonly traditional methods used for the determination of the freshness and authenticity of fish and other seafood products. A special focus is put on the use of rapid and nondestructive techniques (spectroscopic techniques and instrumental sensors) to address several issues related to the quality of these products. Moreover, the advantages and limitations of each technique are reviewed and some perspectives are also given.     

Dietary taurine reduces zinc-induced toxicity in male Wistar rats

Taurine is an agent for treating the heavy metal intoxication and presence of metals such as zinc, copper, and iron may have a role in heavy metal toxicity, a study was undertaken to investigate the effect of taurine on the toxicity of zinc in male Wistar rats. The rats were divided into 8 groups and fed different diets with or without supplement of 5% taurine and 150 to 600 ppm zinc for 2 mo. It was found that the body weight of rats, the ratios of liver and kidney weight to body weight, and the level of glutathione in the liver were decreased with increasing the dose of zinc. The levels of zinc in the liver, kidney, and plasma, the levels of malondialdehyde in the plasma, the levels of thiobarbiture acid-reactive substances in the liver, the activities of aspartate transaminase, alanine transaminase in the plasma, the levels of blood urea nitrogen and creatinine in the plasma of rats were increased with the increasing dose of zinc. Hence, symptoms of zinc toxicity in rats included loss of body weight, hepatotoxicity, and nephrotoxicity. However, these toxic effects of zinc were significantly reduced when the rats fed diet with supplement of taurine. Furthermore, the level of zinc in the feces of rats treated with taurine and zinc was higher than that of rats treated with zinc alone. It indicated that taurine thereby leading to a decreased absorption of dietary zinc and promoted excretion.