Screening of Protease鄄Producing Bacterium for Degrading Castor
Bean Meal and Optimization of Its Fermentation Conditions
WANG Haitao,摇 WANG Changlu
*
,摇 LI Zhenjing,摇 CHEN Mianhua
(
Key Laboratory of Food Nutrition and Safety
,
Ministry of Education
,
Tianjin University of Science and Technology
,
Tianjin
300457,
China
)
Abstract
: A strain named P3鄄2 with the ability to produce protease was isolated from castor bean meal
and laboratory preservation by the casein plate culture method and enzyme activity detection. The optimal
fermentation conditions were investigated. The optimum carbon and nitrate sources were maltose and cas鄄
tor bean meal. Meanwhile, the yield of protease was increased by adding Na
+
and one peak of the prote鄄
ase yield was obtained when the initial pH value of medium was 7郾 5. Moreover, the optimum amount of
inoculum was 4% and there were two peaks of the protease yield when culture time was 36 h and 84 h.
Through the orthogonal experiment, the optimum compositions of medium were as follows: 2郾 0% malt鄄
ose, 1郾 0% castor bean meal, and 1郾 0% NaCl.
Key words
: castor bean meal; protease; screening; fermentation
(
责任编辑
:
叶红波
詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬詬
)
(
上接第
42
页
)
Influence of Chemical Deacidification on Sensory Quality of Italian
Riesling Dry White Wine in Yangling
ZHANG Ruifeng
1,2
, 摇 AN Ran
1
, 摇 CHENG Binhao
1
, 摇 YAN Bin
2
,摇 TAO Yongsheng
1,*
(1郾
College of Enology
,
Northwest A & F University
,
Yangling
712100,
China
;
2郾
COFCO Huaxia Great Wall Wine Co. Ltd.
,
Changli
066600,
China
)
Abstract
: The influence of deacification on the sensory quality of Italian Riesling dry white wine in Yan鄄
gling, Shanxi was studied. After alcohol fermentation, wine was deacidified by different amounts of calci鄄
um carbonate. and wine color was evaluated by detecting CIELab parameters. Wine aroma characteristics
were analyzed and quantified by trained panelists. The total sensory analysis of sample wines was also
made. Data were processed by principal component analysis ( PCA) to show the influence of different
amounts of calcium carbonate on wine color and aroma. Wine treated by 0郾 5 g / L calcium carbonate re鄄
tained the most aroma, and its total sensory score was the highest. After treated by 1郾 0 g / L and 1郾 5 g / L
calcium carbonate, wine had much sweet flavor, less fresh fruity, and lower total sensory score. Mean鄄
while, wine treated by 2郾 0 g / L calcium carbonate lost most fresh fruity and had the lowest total sensory
score. Therefore, the optimum concentration of calcium carbonate for the deacidification of Italian Ries鄄
ling dry white wine in Yangling was 0郾 5 g / L.
Key words
: chemical deacidification; dry white wine; sensory quality; principal component analysis;
Italian Riesling
(
责任编辑
:
李
摇
宁
)
84
食品科学技术学报
摇 摇 摇 摇 摇 摇 摇 摇 摇 摇 摇 摇 摇 摇 摇 摇
摇 2015
年
1
月
