Changes in Anthocyanins and Polyphenolics During Juice Processing of Highbush Blueberries (Vaccinium corymbosum L.)

Frozen blueberries ( Vaccinium corymbosum L.) were processed into juice and concentrate, and the changes in anthocyanin pigments and polyphenolics (cinnamates, procyanidins, flavonol glycosides) were monitored. While juice yield was 83%, only 32% of the anthocyanins were recovered in single-strength juice. Flavonol, procyanidin and chlorogenic acid recoveries in juice were 35%, 43%, and 53%, respectively. The proportion of polyphenolics remaining in the press-cake residue ranged from 1% (chlorogenic acid) to 18% (anthocyanins). Pronounced losses of anthocyanins and polyphenolics during milling and depectinization are believed to be due to native polyphenol oxidase. Losses during concentration ranged from 1.5% (anthocyanins) to 20% (procyanidins). Striking changes occurred in the anthocyanin profile with malvidin glycosides being most stable and delphinidin glycosides the least.     

越桔食品资源的开发与利用

越桔是一种具有极高营养价值和保健功能的食品资源。本文综述了越桔的世界生产贸易和加工利用最新进展 ,并对中国的越桔资源的开发提出了几点建议。     

铁皮石斛花色苷提取及其抗氧化活性分析

以龙江铁皮石斛为试验材料,对微波辅助提取法提取的铁皮石斛花色苷的抗氧化活性进行了综合评价。结果表明:最佳提取条件为乙醇体积分数50%、料液比1︰20(g/mL)、辐射功率406 W、辐射时间90 s、浸泡时间4h、提取次数2次,在此条件下铁皮石斛花色苷含量为1.052 mg/g,花色苷质量浓度为35.07 mg/L。铁皮石斛花色苷有较强的抗氧化能力,且与花色苷质量浓度显现出一定的正比关系,抗氧化效果强于VC。以同浓度梯度的抗坏血酸作对照,根据IC₅₀值的比较可知花色苷的清除效果明显优于同浓度梯度的抗坏血酸。     

蓝莓多酚氧化酶的部分纯化及其酶学特性研究

目的：明确蓝莓多酚氧化酶(PPO)的酶学特性。方法：分别采用硫酸铵分级沉淀法和疏水层析法分离纯化蓝莓PPO,比较两者的纯化效果,并对蓝莓PPO的酶促反应动力学、最适反应温度和pH以及稳定性进行研究。结果：硫酸铵分级沉淀法与疏水层析法的纯化倍数相近,但两者的得率分别为61%和84%。以绿原酸和邻苯二酚为底物时,蓝莓PPO的米氏常数(K_m)分别为23.38mM和6.13mM。该酶的最适pH值为6.0,最适反应温度为25℃。该酶在40℃以上不稳定,而在70℃时,其酶活在60s后残余酶活仅为7.23%。随着pH值的不断降低,其稳定性会不断下降。结论：疏水层析法对蓝莓PPO的分离纯化效果更好。蓝莓PPO对邻苯二酚的亲和力更高,该酶对温度和pH都较为敏感。     

层层自组装可食性涂层在蓝莓常温保鲜中的应用

目的为了延长蓝莓常温保鲜期,优化层层自组装可食性涂层的构建工艺。方法以“绿宝石”蓝莓(Vaccinium rhododendraceae)为试验原料,以糖酸比为单因素的评价指标,考察不同浓度壳聚糖(CS)、羧甲基纤维素钠(CMC)、甘油以及晾干时间对层层自组装可食性涂层保鲜蓝莓的效果,并采用正交试验设计获得层层自组装可食性涂层对蓝莓采后常温保鲜效果最佳的参数。结果层层自组装可食性涂层最佳的构建工艺为CS浓度为6 mg/mL、CMC浓度为10 mg/mL、甘油浓度为0.06 mL/mL、晾干时间40 min。蓝莓常温保鲜期可以达到12 d,测得蓝莓失重率为(23.97±2.64)%,糖酸比为(20.39±0.26)%,明显优于对照组(失重率为(33.04±3.39)%,糖酸比为(25.63±0.29)%(p<0.05)。结论经层层自组装可食性涂层处理的蓝莓,在贮藏期内,失重率、糖酸比下降速率显著放缓,有利于蓝莓的常温保鲜。本研究为层层自组装可食性涂层技术在果蔬保鲜中的实践应用提供了理论依据。     

Authentication of Geographical Origin and Crop System of Grape Juices by Phenolic Compounds and Antioxidant Activity Using Chemometrics

The main goal of this work was to propose an authentication model based on the phenolic composition and antioxidant and metal chelating capacities of purple grape juices produced in Brazil and Europe in order to assess their typicality. For this purpose, organic, conventional, and biodynamic grape juices produced in Brazil (n = 65) and in Europe (n = 31) were analyzed and different multivariate class‐modeling and classification statistical techniques were employed to differentiate juices based on the geographical origin and crop system. Overall, Brazilian juices, regardless of the crop system adopted, presented higher contents of total phenolic compounds and flavonoids, total monomeric anthocyanins, proanthocyanidins, flavonols, flavanols, cyanidin‐3‐glucoside, delphinidin‐3‐glucoside, and malvidin‐3,5‐glucoside. No differences were observed for trans‐resveratrol, malvidin‐3‐glucoside, and pelargonidin‐3‐glucoside between countries and among crop systems. A total of 91% of Brazilian and 97% of European juices were adroitly classified using partial least squares discriminant analysis when the producing region was considered (92% efficiency), in which the free‐radical scavenging activity toward 2,2‐diphenyl‐1‐picrylhydrazyl, content of total phenolic compounds, gallic acid, and malvidin‐3‐glucoside were the variables responsible for the classification. Intraregional models based on soft independent modeling of class analogy were able to differentiate organic from conventional Brazilian juices as well as conventional and organic/biodynamic European juices.     

Frozen Blueberry-soy Dessert Quality

ABSTRACT: Lowbush or wild blueberries ( Vaccinium angustifolium Ait.) and soy protein offer many complementary health benefits; thus, combinations of these 2 foods may appeal to health-conscious consumers. Four frozen dessert formulations were prepared with soy protein isolate and different amounts of blueberry concentrate and puree. Fat content (3% or 10%) was adjusted with soybean oil and nondairy creamer. Consumers ( n = 40) from the campus community used a 9-point hedonic scale to assess acceptability. The 10% fat content and 8.6% blueberry concentrate formulation received the highest overall acceptability (6.63, P < 0.05), compared with formulations with 10% fat and 17.2% blueberry concentrate and 3% fat and 12.9% blueberry concentrate. More than 1 /3 of the panelists are trying to increase blueberry consumption, 20% want to increase soy, and 20% want to eat more of both foods. Development of palatable desserts combining lowbush blueberries and soy protein could lead to increased consumption of both healthy ingredients.     

不同预处理方式对速冻草莓花色苷含量的影响

研究了用不同预处理方式处理的速冻草莓在冻藏期间花色苷含量的变化.速冻预处理溶液采用蔗糖和氯化钙溶液,通过改变浸蘸溶液的质量分数和浸蘸时间来改变处理方式.研究表明,质量分数为20%的糖液浸蘸15 min的预处理方法花色苷的流失最少;5 g/L CaCl2溶液处理10 min的效果最为明显;混合预处理方式与以上两种方式相比,则效果较差.     

花色素苷的研究进展

花色素苷广泛存在于植物内，是重要的呈色物质之一。本文从其结构，性质，以及在人体和动物内的利用、消耗情况、安全性、功能作用、来源等方面对花色素苷全面论述，针对目前国内对花色素苷在动物和人体内的代谢吸收、生物利用率方面研究较少的情况，本文着重介绍了此方面，希望对有关方面的研究有所帮助。