期刊
FOOD HYDROCOLLOIDS
卷 39, 期 -, 页码 204-214出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.foodhyd.2014.01.015
关键词
Oat beta-glucan; Probiotics; Yogurt starter culture; Milk gels; Rheology; Fermentation
The impact of oat beta-glucan fortification (1.4%) on the acidification and gelation kinetics of fermented skimmed milk (12% total solids) as well as the effects of inclusion of a probiotic strain (Lactobacillus paracasei subsp. paracasei B117) into the yogurt starter culture (Lactobacillus delbrueckii subsp. bulgaricus Y 6.15 and Streptococcus thermophilus Y 4.10) and fermentation temperature (36, 38 and 40 degrees C) have been explored by dynamic rheometry, pH measurements and microbial enumeration. The viability/growth of the mixed culture bacteria was also evaluated upon storage. Incorporation of beta-glucan to milk resulted in phase separation between proteins and the added polysaccharide, altering the entire gelation process as manifested by the development of a transient gel structure at the early stages, followed by significant (P < 0.05) retardation of both protein aggregation and acidification kinetics, and finally the formation of significantly weaker gels compared to control formulations. Furthermore, fortification of milk with beta-glucan led to a liquid-like structure (tan delta > 1) at the end of fermentation (pH = 4.6) when performed at 36 degrees C. A higher fermentation temperature accelerated the acidification kinetics, yielding a shorter gelation time, but the storage modulus values of milk gels decreased. Inclusion of the probiotic strain into the yogurt starter culture seemed to increase the gelation rate without affecting the gelation time and gel strength. Viability of all three culture bacteria was enhanced by decreasing fermentation temperature and during storage. Moreover, the L. paracasei showed good compatibility with the yogurt starter culture and the addition of beta-glucan enhanced the viability of the probiotic strain in the fermented products throughout cold storage (4 degrees C). (C) 2014 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据