芦笋保健搅拌酸奶的研制

芦笋是一种兼食品及较强保健功能的稀有蔬菜。对芦笋加工处理、发酵菌种选育驯化、辅料的选择、发酵工艺条件、搅拌方法等一系列的工艺探索,研制出色泽微翠绿、芦笋味典型并适合中老年消费者需求的保健型搅拌酸奶。     

Taste recognition threshold concentrations of styrene in oil-in-water emulsions and yoghurts

Taste recognition threshold concentrations (TRTC) of styrene were determined in samples of oil-in-water emulsions (30–300 g kg^?1 oil) and yoghurts (1–30 g kg^?1 fat), spiked with styrene. The observed TRTC increased linearly with increasing fat content and ranged from 0–3 to 2–1 mg kg^?1 for the emulsions and from 36 to 171 g kg^?1 for the yoghurts. Styrene equilibrium partition coefficients between emulsions and their respective vapour phases were determined. The concentrations of styrene in the continuous aqueous phase of the emulsions and yoghurts were calculated at the TRTC. The styrene concentrations in the continuous phase had constant values of about 15 g kg^?1 indicating that perception of styrene for oil-in–water emulsions is determined by the aqueous phase of the emulsion. The concentrations of styrene in the vapor phases above the emulsions and yoghurts were also calculated and were found to be constant at the TRTC. This relationship probably resulted from the equilibrium of distribution of styrene between the respective phases. Commercial yoghurt packed in polystyrene beakers contained styrene levels in the range 2–11 g kg^?1, much lower then the TRTC reported.     

三聚氰胺对酸乳发酵的影响

为了阐明三聚氰胺对酸乳发酵的影响,以含不同浓度三聚氰胺的鲜牛乳为原料进行了酸乳的发酵实验,测定了发酵过程中的pH值、发酵前后的活菌数及凝乳时间.结果表明：添加三聚氰胺会增大凝乳时的pH值,变化的最大值为0.78;也会增加凝乳时间,增加的最大值为1.5 h;凝乳时,乳酸菌的活菌数有所下降,但下降值不超过一个数量级;酸乳中三聚氰胺浓度越高,凝乳时质地越疏松;酸乳中菌体的形态差异并不明显.     

酸乳制品中乳酸菌分离筛选方法研究

将保加利亚乳酸杆菌和嗜热链球菌在七种固体培养基中的生长情况进行比较，结果表明，酸化ＭＲＳ和Ｍ１７培养基分别是该两菌的较好的分离培养基。菌种的筛选应进行产酸风味和组织状态的综合比较，两菌不同组合菌株的选择应结合不同发酵条件进行。通过该方法分离筛选到不同风味类型的两组混菌。     

Viability of Lactobacillus acidophilus in rice bran‐enriched stirred yoghurt and the physicochemical and sensory characteristics of product during refrigerated storage

This study was aimed at investigating the fortification of probiotic yoghurt with rice bran to increase nutritional properties of the product. The different levels of rice bran (0.3%, 0.6%, 0.9% and 1.2%) were incorporated into milk. The yoghurt samples were produced after pasteurisation, addition of starter culture and 1% Lactobacillus acidophilus suspension (6 × 10⁸ CFU mL^?1) and incubation. During sample storage in refrigerator, the viability of L. acidophilus, viscosity and physicochemical and sensory properties of product were investigated. Rice bran significantly increased the viability of L. acidophilus (P < 0.05). In addition, all probiotic yoghurts incorporating rice bran indicated higher viscosity and acidity and lower pH and syneresis compared to plain yoghurts. Furthermore, increments in rice bran incorporation levels resulted in a reduction in consumers' sample preferences. In general, the addition of rice bran at a suitable level could increase L. acidophilus viability and improve quality attributes of yoghurt.     

Strained fermented milks – A review of existing legislative provisions,survey of nutritional labelling of commercial products in selected markets and terminology of products in some selected countries

A survey of the information contained in the labels of 109 commercial concentrated fermented milks from the Eastern Mediterranean, Australasia, the United Kingdom, Ireland, the United States of America and Canada plus Skyr (from Iceland), Ymer (from Denmark) and Chakka (from India) was carried out in late 2012 and early 2013. There were substantial differences in composition. The carbohydrate, fat and protein contents ranged between 1–12, 0–20 and 3.3–11 g/100 g, respectively. Considering the compositional data of the product and existing legislative provisions, a typical strained product should have a protein content of ≥8 g/100 and ~5 g/100 g of carbohydrates, and it would be appropriate to name such products as ‘strained yoghurt’, ‘Greek strained yoghurt’ and/or ‘Labneh’. A higher content of carbohydrate would suggest that the product was made using the product formulation method (i.e. without straining the fermentate), or the milk base had been fortified with skimmed milk before straining the fermentate to enhance the yield of the product, and such products should be known, for example, as ‘Greek‐style yoghurt’. It was also observed in some of the samples that the nomenclature of the starter cultures did not conform to recommendations of the International Union of Microbiological Societies (IUMS). Manufacturers could address such issues to minimise consumer confusion.     

乳清浓缩蛋白在酸奶生产中的应用

以鲜奶，奶粉，乳清蛋白等乳成分为主要原料，研究了乳清浓缩蛋白在酸奶生产中的制做方法，对乳清浓缩蛋白代替部分高档脱脂奶粉生产酸奶产品的保水率，粘度，口感及组织状态进行了比较分析。结果表明，在酸奶生产中，添加一定的浓缩乳清蛋白代替高档脱脂奶粉是可行的，产品较为理想。     

花生凝固型酸乳配方的响应面法优化

以新鲜花生和鲜牛乳为主要原料,配制、发酵的凝固型酸乳。在单因素实验的基础上,利用Design–Expert软件进行三因素三水平的二次回归中心旋转组合实验设计(Central Composite Design,CCD),并对花生凝固型酸乳配方参数进行优化分析。通过响应面分析确定花生凝固型酸乳的最佳配方:花生浆与牛乳比例为1∶2.5(v/v),蔗糖添加量为4.30%,稳定剂添加量为0.92%,在此条件下,发酵的花生凝固型酸乳口感、质地良好。成品酸度94°T,持水力33%,黏度561 m Pa·s。     

双歧杆菌选择计数方法的研究进展

综述了近年来双歧杆菌选择计数方面的研究进展。介绍了国外报道的几种应用效果较好的选择计数培养基,提出了这方面需要进一步开展的工作与想法。     

芹菜大豆酸奶的研制

以芹菜和大豆为原料，在豆乳中加入芹菜汁．再以保加利亚乳杆菌和嗜热链球菌为发酵剂进行乳酸发酵．用正交试验得出最佳配料组合。结果表明芹菜汁添加量为8％，保加利亚乳杆菌和嗜热链球菌(1：1)添加量为4％，白砂糖添加量为7％．稳定剂用量为0．30％，在43℃条件下发酵4～5h，可制得风味、口感俱佳的芹菜酸豆奶。