黄芪功能性酸奶的研究

由黄芪和鲜牛奶为主原料,研制出了集黄芪和酸奶的保健功能于一体的新型保健饮料——黄芪功能性酸奶。采用正交实验筛选出最优组合,结果表明:黄芪汁∶牛奶=0.2∶1,接种量为5%,加糖量为7%,发酵时间9h为最佳的工艺条件,得到的酸奶品质最好。     

混合果肉酸奶的研制

在酸奶技术的基础上,将猕猴桃与鲜牛乳的混合液接入乳酸菌发酵。采用单因素实验设计和正交实验设计,用保加利亚乳杆菌和嗜热链球菌混合发酵猕猴桃牛乳混合液,以乳清析出率、酸度和感官质量评定为依据,筛选出产品的最佳配方工艺条件为鲜牛乳81.7%、猕猴桃8%、另加蜂蜜量4%、稳定剂0.32%、发酵接种量3.0%、41℃下发酵6h,而后添加3%的葡萄干、0～4℃下后熟12h。该果肉酸奶的感官评定值可达91～95。     

枸杞保健型发酵酸乳的研制

以牛乳和枸杞为主要原料进行枸杞保健型发酵酸乳的研制，通过研究确定了枸杞的最佳添加量及最佳发酵时间，通过L9（3^4）因素3水平正交实验和对产品综合评分，确定了产品最佳配方为枸杞的添加量0.2%、接种量3%、白砂糖6%、果胶添加量0.1%。     

低聚异麦芽糖改善小鼠胃肠道功能的研究

以二月龄雄性BALB／c小鼠为实验对象,研究了IMO－50与IMO－90调节胃肠道菌群的功能,结果表明：连续给予IMO－50或IMO－9014天后,小鼠胃肠疲乏内双歧杆菌数量显著增加。以二月龄雄性BALB／c小鼠为实验对象,以复方地芬诺酯建立的便秘模型为参比对照,研究IMO-50IMO－90的润畅通便功能,结果表明：在连续给予受试物14天后,便秘小鼠的肠推进率显著提高,首便、首黑便时间明显缩短,8小时排便重量显著增加。提示IMO－50和IMO－90均可改善小鼠胃肠道功能。     

Bifidobacterium carbohydrases-their role in breakdown and synthesis of (potential) prebiotics

There is an increasing interest to positively influence the human intestinal microbiota through the diet by the use of prebiotics and/or probiotics. It is anticipated that this will balance the microbial composition in the gastrointestinal tract in favor of health promoting genera such as Bifidobacterium and Lactobacillus. Carbohydrates like non-digestible oligosaccharides are potential prebiotics. To understand how these bacteria can grow on these carbon sources, knowledge of the carbohydrate-modifying enzymes is needed. Little is known about the carbohydrate-modifying enzymes of bifidobacteria. The genome sequence of Bifidobacterium adolescentis and Bifidobacterium longum biotype longum has been completed and it was observed that for B. longum biotype longum more than 8% of the annotated genes were involved in carbohydrate metabolism. In addition more sequence data of individual carbohydrases from other Bifidobacterium spp. became available. Besides the degradation of (potential) prebiotics by bifidobacterial glycoside hydrolases, we will focus in this review on the possibilities to produce new classes of non-digestible oligosaccharides by showing the presence and (transglycosylation) activity of the most important carbohydrate modifying enzymes in bifidobacteria. Approaches to use and improve carbohydrate-modifying enzymes in prebiotic design will be discussed.     

搅拌型酸奶应力松驰行为的研究

目的以搅拌型酸奶为研究对象,建立一种应力松驰行为评价的测试方法。方法对酸奶施加应变,研究其松驰模量随时间的变化规律,并对方法的实验参数进行优化,并对市面上流行的7类搅拌型酸奶进行应力松驰行为的测试。结果通过应变扫描确定了酸奶的线性粘弹性区域,结合不同应变大小时的应力松驰实验结果,最终选择1%作为酸奶应力松驰实验特性研究时的应变值;进一步研究了不同松驰时间对松驰模量的影响,最终选择60 min作为松驰时间。酸奶在松驰初始阶段及松驰结束时的松驰模量差异明显,可以评判酸奶的弹性大小与松驰时间内松驰模量的损耗情况。酸奶的应力松驰行为可以通过6个Maxwell模型进行表征,不同松驰时间下起主要作用的应力松驰特征模量与特征时间的Maxwell模型数存在明显差异。结论通过应力松驰行为的测试可以评价搅拌型酸奶的粘弹性特性。     

Value addition to frozen yoghurt through the use of orange peel solids as flavour adjunct

Frozen yoghurt rich in β-carotene and dietary fibre was developed through incorporation of orange peel products. The suitability of two forms of peel viz., candied orange peel (COP) and orange peel powder (OPP), was studied as flavour adjunct in frozen yoghurt. The medium-fat frozen yoghurt mix was prepared by blending yoghurt base with ice cream mix (25:75, w/w). COP and OPP were used as flavour adjuncts at levels of 8.0 and 2.5% by weight of mixes, respectively. The control (C) frozen yoghurt was devoid of the fruit peel. Incorporation of peel solids yielded frozen yoghurts which had markedly higher protein, carbohydrates, ash and total solids content. OPP used at 2.5% level was preferred over use of COP at 8.0% level as a valued ingredient in the preparation of ‘medium-fat orange frozen yoghurt’. Such product had superior total sensory score when compared to the rest of the samples. The recommended frozen yoghurt was higher in terms of β-carotene and dietary fibre by 37.20 and 240.0%, respectively, compared to control product.     

不同热处理无乳糖酸奶与普通酸奶品质的比较

确定合适无乳糖酸奶工艺的热处理温度,探究热处理对无乳糖酸奶在表观黏度、色度、滋味、气味、贮藏稳定性以及微观结构影响并与普通酸奶进行比较.结果表明:无乳糖酸奶的表观黏度略高于普通酸奶;在滋味方面,无乳糖酸奶的苦味、咸味、甜味要低于普通酸奶,经过75℃、15 min热处理的无乳糖酸奶风味表现最为协调;在气味和色度方面,不同...     

The effect of hydrolysed tragacanth gum and inulin on the probiotic viability and quality characteristics of low‐fat yoghurt

This study investigates the effect of supplementation of tragacanth gum (GT, 0.05% w/v), low molecular weight gum tragacanth (LMWGT, 0.5% w/v) and inulin (0.5% w/v) on the viability of Bifidobacterium bifidum and the quality parameters of low‐fat yoghurt during a three‐week storage period. The count of probiotics was found to be 7.8 log cfu/g in inulin, and LMWGT enriched yoghurts at the end of the storage period. The minimum water holding capacity and the maximum syneresis values were also obtained in the low‐fat yoghurt enriched with GT throughout the storage time. The samples containing inulin and LMWGT revealed sensory attributes that were judged superior compared to those in GT.