Table of Content

30 April 2014, Volume 37 Issue 2

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Biotechnology

Probiotic Properties of Saccharomy cescerevisiae and Screening of Strains Symbiotic with Lactobacillus plantarum IMAU10120

ZHAO Xiao-yan, GAO Peng-fei, YAO Guo-qiang, LI Jing, GUO Jian-lin, GUO Xiao, WANG Xiao-wei, ZHANG He-ping

2014, 37(2):  1-5.  DOI: 10.15922/j.cnki.jdst.2014.02.001

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In this study, 30 strains of S. cerevisiae were examined by in vitro gastrointestinal transit, bile salt tolerance and microbial inhibition tests to screen strains having potential probiotic properties and a symbiotic relationship with Lactobacillus plantarum IMAU10120 from them. The results showed that S. cerevisiae IMAU6Y047, IMAU7Y006, IMAU7Y007 and IMAU7Y036 were bile salt-tolerant strains and had a high survival rate over 50% during gastrointestinal transit. They were also resistant to E. coli O157, Salmonella typhimurium and Shigella flexneri. In addition, IMAU7Y006 had mutualism relationship with Lactobacillus plantarum IMAU10120. This study may provide basic data for further study on mixed-strain fermentation.

Association of Polymorphisms in the AGPAT6 Gene with Body Size Traits in Different Dairy Goat Breeds

CHANG Zhen-hua, HE Cheng, YAN Wei-jun, WANG Wei-hua, MENG Xiao-jing

2014, 37(2):  6-8.  DOI: 10.15922/j.cnki.jdst.2014.02.002

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The associations between AGPAT6 gene polymorphisms and body size traits (body height, body length, chest circumference) were investigated in 549 Xinong Saanen and Guanzhong dairy goats using PCR-RFLP techniques. Four single nucleotide polymorphisms (SNPs) including 5'UTR (g.152G ＞ C), intron2 (g.8124G ＞ A), exon4 (g.9263C ＞ G) and 3’UTR (g.16436G ＞ A) were detected in four loci (P1, P2, P4 and P10) respectively. The population genetic analysis showed that P2, P4 and P10 possessed intermediate polymorphism. The association study revealed that none of the four SNPs detected had a significant effect on the body traits in the two goat breeds (P ＞ 0.05).

Processing Technology

Formulation Optimization of a Dairy Beverage with Tremella fuciformis

LIU Jian-ying，WANG Da-wei

2014, 37(2):  9-13.  DOI: 10.15922/j.cnki.jdst.2014.02.003

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High-temperature, high-pressure extruded Tremella fuciformis was applied in a dairy beverage. Beverage samples were prepared with different proportions of citric acid, Tremella fuciformis, milk powder, composite stabilizer and white soft sugar and were evaluated for stability and sensory attributes. The optimal proportions of these ingridents were optimized by orthogonal array design to be 0.10%, 15%, 2%, 0.20% and 8%, respectivley. The resulting beverge was stable, rich in nutrients and had a pure flavor.

Optimization of Fermentation Conditions for the Production of Waxy Maize Yogurt by Orthogonal Array Design

GUO Qi-zhen, LI De-long, WU Jin-hong, QIAN Fu-rong, GAO Yan-ling

2014, 37(2):  14-18.  DOI: 10.15922/j.cnki.jdst.2014.02.004

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Purpose: To develop a peptide-rich beverage from skim milk powder and waxy maize. Methods: The bitterness flavor of dry waxy maize was removed and then pretreated sequentially with α-amylase and gluco-amylase before being mixed with reconstructed milk and the starting cultures used were a mixture of Streptococcus thermophilus TA40 and Lactobacillus helveticus LH100 (1:1, m/m). Results: The optimal pretreatment conditions were established for waxy maize. The optimal fermentation conditions were determined as 4% (m/m) of whey protein added into reconstituted milk with a skim milk powder to water ratio of 1:0.8:13 (m/m), 4 g/L inoculum size, and fermentation at 37 ℃ for 8 h. The peptide content of the resulting beverage was measured to reach 4.6658 mg/mL. Sensory evaluation and physiological analysis showed that the pH, acidity and viscosity were 3.94, 132.7 oT and 5.276 Pa?s, respectively, and the beverage had a mixed flavor of waxy maize and yogurt but exhibited no obvious whey syneresis.

Formulation Optimization of a Milk Beverage with Added Proanthocyanidins from Purple Corn

SONG Shuang，WANG Da-wei

2014, 37(2):  19-23.  DOI: 10.15922/j.cnki.jdst.2014.02.005

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The aim of this study was to optimize the formulation of a milk beverage with added proanthocyanidins from purple corn by one-factor-at-a-time and orthogonal array design methods. Beverage samples with different proportions of white soft sugar, milk powder, CMC and citric acid were examined for stability and sensory attributes. The results showed that the milk beverage formulated from 6% soft sugar, 3% milk powder, 0.10% CMC and 0.15% citric acid was stable and had a pure taste and an excellent quality.

Effects of Different Nutrients on Polysaccharide Production during Kefir Fermentation

FAN Xiu-fang, CHEN Gang, GENG Ying-long, JIAN Su-ping

2014, 37(2):  24-27.  DOI: 10.15922/j.cnki.jdst.2014.02.006

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In this study, the production of polysaccharides by kefir grains during milk fermentation was optimized with respect to the amount of nutrients added to the fermentation medium (sterilized milk) employing one-factor-at-a-time and orthogonal array design methods. The results showed that the optimal carbon sources added to sterilized milk were 3% maltose, 4% sucrose and 4% glucose, resulting in a maximum yield of polysaccharides of 1.92 g/L, the optimal nitrogen sources were 0.2% yeast extract, 1% peptone and 0.004% L-tyrosine, resulting in a maximum yield of polysaccharides of 2.07 g/L, and the optimal inorganic salts were 0.4% KH2PO4, 0.08% MgSO4·7H2O, 0.02% CaCO3 and 0.25% NaCl, resulting in a maximum yield of polysaccharides of 2.01 g/L.

Analysis & Detection

A Method for Prejudging the Stability of Sterilized Milk

ZHANG Feng-hua

2014, 37(2):  28-31.  DOI: 10.15922/j.cnki.jdst.2014.02.007

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3e

Reviews

Analysis of Dairy Product Quality and Safety Traceability System

CHEN Xiang-yu

2014, 37(2):  32-35.  DOI: 10.15922/j.cnki.jdst.2014.02.008

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With the development of the society and the improvement of living standards, the dairy quality and safety is attracting increasing attention. However, with the extension of the dairy supply chain and the complexion of the participants’ behavior, it is difficult for consumers to get information about the quality and safety of dairy products. As an effective means of dairy quality and safety management, more and more attention has been paid to dairy quality safety traceability system by relevant departments and consumers. This paper is aimed at reviewing the dairy quality and safety situation in our country, expounding the necessity of establishing quality and safety traceability system, analyzing the problems faced by the promotion of system, proposing some ideas on how to build the framework, and put forward some policy suggestions for system construction.