肉桂精油-β-环糊精微胶囊的制备

肉桂精油有很好的抑菌性能,而其挥发性使得其作为食品防腐剂的应用受到了限制。为扩大肉桂精油在食品中的应用,采用β-环糊精包埋法研究了肉桂精油微胶囊工艺,通过单因素试验和正交试验确定肉桂精油微胶囊制备的较好工艺条件为芯壁材质量比(肉桂精油∶β-环糊精)为1∶8,包合温度为70℃,包合时间为2 h。此工艺条件下制备的微胶囊包埋率可达86.75%。     

响应面法优化肉桂精油微胶囊制备工艺的研究

肉桂精油是一种从肉桂树皮中提取的以醛类和酯类为主要成分的挥发性油,由于其易受贮藏条件的影响使得主要成分挥发而导致抑菌和抗氧化效果减弱,因此利用高分子物质包埋肉桂精油形成微胶囊,不仅可以提高肉桂精油的稳定性,还能降低其在贮藏过程中的挥发损耗。本研究以肉桂精油为芯材,β-环糊精为壁材,采用饱和水溶液法制备肉桂精油微胶囊,首先建立了包埋率与芯壁比、壁材浓度、包埋温度、包埋时间四个单因素之间的数学模型,在单因素试验的基础上进行响应面优化试验,从而确定肉桂精油微胶囊的最佳包埋工艺参数。结果表明,芯壁比为1∶8、壁材浓度为29%、包埋温度为51℃条件下反应1.9 h后包埋效果最佳,包埋率达到了80.19%,此结果为肉桂精油微胶囊制备工艺提供了有效的参数支持。     

香辛料精油-β–环糊精微胶囊的物理特征及对酱牛肉熏蒸保鲜的效果研究

利用包埋法制备了肉桂精油、丁香精油、肉桂-丁香复合精油三种不同芯材的β–环糊精微胶囊,考察精油的种类对微胶囊包埋率,热稳定性的影响,测定三种微胶囊的挥发性成分对大肠杆菌和金黄色葡萄球菌的最低抑菌浓度(MIC),并通过熏蒸的方法观察不同芯材的微胶囊对酱牛肉冷藏期间菌落总数和感官的变化。结果表明:精油种类对微胶囊的包埋率有明显影响,以肉桂精油微胶囊的包埋率最高,为70.00±0.62%;对微胶囊的热稳定性没有显著影响;对微胶囊挥发性成分的抑菌性能有不同程度的影响,以肉桂精油微胶囊对两种受试细菌的MIC最低,分别为:16、32mg/cm3;对酱牛肉熏蒸抑菌的结果显示三种不同芯材的微胶囊均能显著抑制酱牛肉冷藏(4℃)期间总菌数,以肉桂精油微胶囊的抑菌性能最好;对酱牛肉冷藏期间的感官变化没有显著差异。     

肉桂-丁香-百里香精油微胶囊的制备及表征

为了获得用于不同运输条件下对稻谷中的霉菌具有天然抑菌效果的精油微胶囊,以肉桂、丁香和百里香精油为芯材,以明胶、阿拉伯胶为壁材,采用复凝聚法制备肉桂-丁香-百里香精油微胶囊.通过热重分析法和扫描电镜分析精油微胶囊的结构和理化特性,并对精油微胶囊在霉变稻谷中的缓释抑菌效果进行比较.结果表明,制备精油微胶囊的最优工艺条件为:...     

艾蒿油微胶囊的制备及其抗菌性研究

艾蒿,是常见的菊科蒿属多年生野生草本植物,其精油具有广谱抗菌作用。本文以明胶、阿拉伯胶为壁材,艾蒿精油为芯材,采用复凝聚法制备具有抗菌保健功能的微胶囊,主要研究了体系中明胶与阿拉伯胶的比值,凝聚时的搅拌速度及固化剂戊二醛的用量对微胶囊微观形态的影响。研究表明,m(明胶):m(阿拉伯胶)=1∶1,搅拌速度为300 r/min,戊二醛用量与明胶用量相同时,可获得形态规整,大小均一的微胶囊,对大肠杆菌、金黄色葡萄球菌及黄曲霉菌均有良好的抗菌作用。     

复合精油涂层对干腌火腿抑菌及抗氧化作用的影响

以猪油和淀粉为抗氧化涂层基料、山苍子精油和肉桂精油为抑菌及抗氧化剂制备涂层材料,通过单因素试验和正交试验研究不同山苍子精油和肉桂精油配比、复合精油添加量和强化高温成熟温度对火腿半膜肌的抗氧化及抑菌作用。结果表明:当山苍子精油和肉桂精油配比为1∶0.5~1∶2(m/m)、复合精油添加量为0.03%~0.05%(以涂层基料总质量计)时,复合精油涂层对火腿半膜肌的脂质氧化、菌落总数及霉菌数均有较好的抑制作用;在山苍子精油和肉桂精油配比为1∶1、复合精油添加量为0.05%、强化高温成熟温度为35℃的最佳工艺条件下,火腿半膜肌的硫代巴比妥酸反应物质(thiobarbituric acid reactive substances,TBARs)值为0.549 mg MDA/kg、霉菌数为1.341(lg(CFU/g))、菌落总数为3.662(lg(CFU/g)),与未涂层组相比分别降低了24.0%、43.4%和31.1%。可见复合精油涂层能显著降低火腿半膜肌的脂质氧化程度、抑制微生物的生长。     

ASLT法研究复合精油微胶囊对大米保鲜效果

采用共沉淀法制备壁材为β-环糊精,芯材为对大米病原菌黄曲霉有高抑菌性的大蒜精油与肉桂精油复合精油的微胶囊保鲜剂;将微胶囊用无纺布包装成小袋置于大米PE包装袋中,采用加速货架期试验,根据大米脂肪酸值的变化评价其保鲜效果,并预测大米货架寿命;同时分析大米感官评分与脂肪酸值的相关性,为快速判断大米质量提供参考。结果表明:大蒜精油和肉桂精油对黄曲霉抑制效果显著,复合精油以大蒜精油:肉桂精油为1:3组成;SEM表征分析微胶囊呈不规则形状,复合精油微胶囊处理的大米脂肪酸值的变化速度明显低于对照组,预测复合精油微胶囊处理的大米在室温(25℃)的货架寿命为415 d,而对照组大米货架寿命仅为122 d;大米感官评分与脂肪酸值变化具有一定的相关性。     

喷雾干燥法制备肉桂精油微胶囊化工艺条件的优化

以包埋率为考察指标,运用单因子和响应面方法对喷雾干燥法制备肉桂精油微胶囊的工艺条件(进口温度、喷雾压力、进料速度)进行优化。结果表明:喷雾干燥法制备肉桂精油微胶囊的最佳工艺条件为进风温度185℃,喷雾压力0.35MPa,进料速度53mL/min,此条件下得到的包埋率为94%。验证实验包埋率为93.5%,与理论值94%相差0.53%,该数值没有超出误差范围。说明运用响应面方法优化喷雾干燥法制备肉桂精油微胶囊的工艺条件有效可行,以期为工业化生产奠定良好的基础。     

壳聚糖-薄荷精油微胶囊的制备及其性能

为了开发缓释型芳香功能材料和纺织品,通过单凝聚法制备薄荷精油微胶囊,以粒径和包埋率为指标,通过单因素法优化薄荷精油微胶囊的制备工艺,利用扫描电子显微镜(SEM)观察微胶囊表面形态;通过红外分析固化前后囊壁分子基团的变化,并测试了薄荷精油微胶囊的缓释性、热稳定性等。结果表明,薄荷精油微胶囊的制备工艺为：以Span80和Tween80复配作为乳化剂,选择分子量约为30000的壳聚糖为壁材,芯材薄荷油与壁材壳聚糖质量比为1∶1,加入质量分数为100%(对壳聚糖用量)的戊二醛固化1 h。薄荷精油微胶囊的平均粒径约为2.8μm,包埋率达66.67%,常温条件一个月后保留率为65.24%,高温(120℃)2 h后保留率为76.23%,红外分析表明壳聚糖经固化后形成交联结构,热重分析表明薄荷精油微胶囊具有良好的热稳定性。薄荷精油经过微囊化处理后提高了稳定性,有利于进一步拓宽应用范围。     

海藻酸钠/多孔淀粉牛至精油微胶囊的制备

为提高对天然植物精油的包埋效果,以海藻酸钠和多孔淀粉为壁材,以牛至精油为芯材,采用锐孔法制备多孔淀粉/海藻酸钠牛至精油微胶囊。通过单因素实验和正交实验对精油微胶囊的制备工艺进行了优化,并通过扫描电镜对精油微胶囊的结构进行了表征。得到精油微胶囊优化的制备条件为:精油淀粉比1∶3,海藻酸钠溶液浓度2.5%,氯化钙浓度1.5%,针头型号9号,在此条件下精油微胶囊包埋率为88.25%,产率为44.27%,粒径为915μm。扫描电镜图像结果表明以多孔淀粉与海藻酸钠为壁材制得的微胶囊外观良好,表面呈交联多孔结构,一定程度上弥补了单一壁材海藻酸钠所制微胶囊外观上的缺陷。     

Probiotics and prebiotics--perspectives and challenges

Owing to their health benefits, probiotics and prebiotics are nowadays widely used in yogurts and fermented milks, which are leader products of functional foods worldwide. The world market for functional foods has grown rapidly in the last three decades, with an estimated size in 2003 of ca US$ 33 billion, while the European market estimation exceeded US$ 2 billion in the same year. However, the production of probiotics and prebiotics at industrial scale faces several challenges, including the search for economical and abundant raw materials for prebiotic production, the low-cost production of probiotics and the improvement of probiotic viability after storage or during the manufacturing process of the functional food. In this review, functional foods based on probiotics and prebiotics are introduced as a key biotechnological field with tremendous potential for innovation. A concise state of the art addressing the fundamentals and challenges for the development of new probiotic- and prebiotic-based foods is presented, the niches for future research being clearly identified and discussed.     

常用消毒灭菌法及其机理与应用

介绍了采用消毒灭菌方法,有加热消毒法,紫外线辐射法和化学药剂消毒法。常用化学药剂有醛类、含氯消毒剂、醇类消毒剂以及高锰酸钾、生石灰等,阐释了消毒与灭菌两个概念的区别。     

European citizen and consumer attitudes and preferences regarding beef and pork

This paper presents the combined mid-term findings of the consumer research components of two EU Sixth Framework Programme integrated projects concerning meat, ProSafeBeef and Q-PorkChains. The consumer pillar of ProSafeBeef carried out eight focus group discussions in May 2008, in France, Germany, Spain and the UK. Q-PorkChains conducted a large-scale, web-based, consumer survey in January 2008 in Belgium, Denmark, Germany, Greece and Poland. The first project provides a set of qualitative data from a small cohort of focus groups and the second a set of quantitative data from a larger consumer sample. This paper draws together the main findings of both projects and provides a comprehensive overview of European citizens’ and consumers’ attitudes towards and preferences regarding beef and pork. In general, consumers consider meat to be a healthy and important component of the diet. Consumers support the development of technologies that can improve the health attributes of meat products and guarantee eating quality, but they have a negative view of what they see to be excessive manipulation and lack of naturalness in the production and processing of beef products. In the Q-PorkChains study consumer and citizen segments are identified and profiled. Consumer segments were built upon the frequency and variety of pork consumption. The citizen segments were built upon their attitudes towards pig production systems. Overall, the relationship between individuals’ views as citizens and their behaviour as consumers was found to be quite weak and did not appear to greatly or systematically influence meat-buying habits. Future studies in both projects will concentrate on consumers’ acceptance of innovative meat product concepts and products, with the aim of boosting consumer trust and invigorating the European beef and pork industries.     

毛霉型低盐速成豆豉工业化生产工艺与设备

本文介绍了毛霉型低盐速成豆豉的工业化生产工艺及生产线的关键设备。     

原花色素及其开发应用

对原花色素的结构、化学特性、制备、分析方法、应用前景作一综述,并重点讨论其生理功能,为在功能性食品、药物、化妆品等领域的深入研究和开发提供参考。     

益生素、益生菌与结肠癌

介绍了益生素和益生菌及其作用机理。在动物模型中，有大量的数据证实益生素和益生菌能够预防癌症．而在人体内还没有直接实验证据。它们抑制癌症的确切机理目前尚不清楚，其抑制机理可能是：肠道菌群代谢活动的改变，肠道理化环境的改变，潜在的致癌物质的黏附和降解，肠道菌群的改变、抗癌或抗诱变物质的形成、提高宿主的免疫应答、影响宿主的生理活动以及发酵不能被消化的食物并形成有益代谢产物。     

组学技术与果蔬采后质量和安全控制

果蔬可以提供营养, 有利于人类健康, 而果蔬的后熟及其与环境的相互作用会影响果蔬采后的质量和安全。对果蔬生物学过程的了解和掌握是减少果蔬采后损失和保障果蔬采后质量和安全的关键。在过去的10多年, 基于组学技术的系统生物学在了解果蔬后熟及其与环境相互作用的分子机制方面得到了越来越多的应用。本文对此做了细致的总结, 指出了存在的不足, 并提出了未来的发展方向。     

天然香精香料与生物技术

天然香精香料是高价值的精细化工产品和食品添加剂,但原料来源有限且提取成本高。利用生物技术生产这类产品具有广阔的前景。简述了发酵工程、酶工程、细胞工程和基因工程在香精香料中的应用,并探讨了生物技术在香精香料中的应用前景。     

节能节水型印染助剂和设备的现状

从节能、节水、缩短工艺流程和环保的角度出发,介绍了国内外研制开发的一系列新型节能、节水型印染助剂和染整设备。     

Heritability and correlations for body condition score and dairy form within and across lactation and age

The objectives of the current study were to investigate the relationship between body condition score (BCS) and dairy form and changes in genetic parameters for BCS and dairy form within and across lactations and age. Body condition score and dairy form were obtained from the Holstein Association USA, Inc. Records were edited to include those cows classified between 24 and 60 mo of age and between 0 and 335 d in milk (DIM). A minimum of 20 daughters per sire and 15 cows per herd-classification visit were required. The dataset consisted of 135,178 records from 119,215 cows. Repeatability, multiple trait, and random regression models were used to analyze the data. All models included fixed effects for herd-classification visit, age within lactations 1, 2, and 3 or higher, and 5th-order polynomials for DIM. Random effects included sire and permanent environment for all models. Random regression models included age at classification nested within sire or DIM and lactation number nested within sire. Genetic variance for both BCS and dairy form was lowest in early lactation and highest in midlactation. Genetic correlations within and across lactations were high. The genetic correlation between DIM 0 in lactation 1 and DIM 305 in lactation 3 was estimated to be 0.77 for BCS and 0.60 for dairy form. The genetic correlation estimate between 30 mo of age at classification and 50 mo of age at classification was 0.94 for both dairy form and BCS. The repeatability models appeared to generate accurate evaluations for BCS or dairy form at all ages and stages of lactation.