Table of Content

30 June 2012, Volume 35 Issue 3

Previous Issue    Next Issue

Basic Research

Effect of Melatonin Fortified UHT Milk on Improving Sleep

2012, 35(3):  1-3.  DOI: 10.15922/j.cnki.jdst.2012.03.001

Asbtract ( )   HTML ( )   PDF (119KB) ( )  

Related Articles | Metrics

This study was carried out to examine if melatonin fortified UHT milk (the melatonin content is 3 mg/250 mL) has sleep-improving effects. Our results demonstrate that the fortified milk could obviously shorten the sleep onset latency of animals injected with napental, prolong sleep time and increase the number of sleeping animals injected with napental at subthreshold doses and had no direct hypnotic effect. In conclusion, melatonin fortified UHT milk has sleep-improving effects.

Effect of Calcium-Chelating Salts on Stability of Formulated Milk Beverage during Processing and Storage

2012, 35(3):  4-8.  DOI: 10.15922/j.cnki.jdst.2012.03.002

Asbtract ( )   HTML ( )   PDF (678KB) ( )  

Related Articles | Metrics

In a milk beverage system, proteins may easily loss their stability during processing and storage, causing quality deterioration. The presence of calcium-chelating salts (CCS) is good for dissociating casein micelles and can increase the release of casein to the aqueous phase, therefore resulting in improved stability. In order to understand the influence of different types of CCS on protein stability during beverage processing and storage, a stimulated model of formulate milk beverage was established and used to study the effects of four different types of CCS at four different concentrations on its turbidity, solubility, particle size distribution and caseins after heat treatment. Meanwhile, changes in the solubility and caseins of the system were tested during storage. The results showed that CCS improved the stability of milk beverage system, especially during storage. Higher chelating ability resulted in better stability. However, it was also found that salts with higher chelating ability may cause gelation and aggregation.

Biotechnology

Antiproliferative Effect of 4 Lactobacillus Strains on Colonic Cancer Cells

2012, 35(3):  9-13.  DOI: 10.15922/j.cnki.jdst.2012.03.003

Asbtract ( )   HTML ( )   PDF (158KB) ( )  

Related Articles | Metrics

In this study, heat-killed bacterial cells, genomic DNA, and cell wall of 4 Lactobacillus strains isolated from traditional dairy food in China, Lactobacillus paracasei supsp. paracasei M5AL, L. paracasei supsp. paracasei J23ANL, L. paracasei supsp. paracasei G15AL, L. coryniformis supsp. torquens T3AL, were tested in vitro for their antiproliferative effect on colonic cancer cell line HT-29 by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. All heat-killed bacterial cells, genomic DNA, and cell wall of these 4 strains exhibited direct antiproliferative activities against HT-29 cells. Lactobacillus coryniformis ssp. torquens T3AL exerted significantly stronger antiproliferative activities against HT-29 cells (P＜0.05) than other three strains. The results of single cell gel electropherosis showed that the strain T3AL could induce apoptosis of HT-29 cells. Further study is needed to explain the mechanism of apoptosis of HT-29 cells induced by the strain.

Processing Technology

Formulation Optimization of Non-Sugar Flavored Milk

2012, 35(3):  14-16.  DOI: 10.15922/j.cnki.jdst.2012.03.004

Asbtract ( )   HTML ( )   PDF (123KB) ( )  

Related Articles | Metrics

The effect of various sweeteners on the quality of flavored milk was studied to determine optimal sweetener blend for flavored milk. Further, the formulation of non-sugar flavor milk was optimized. The results showed that the optimal sweetener blend was formulated from 25% sucralose, 25% neotame and 50% aspartame. The optimal formula for non-sugar flavor milk was 0.2% stabilizer, 0.6% walnut powder, 100% sucrose substitution. The developed non-sugar flavored milk presented no substantial difference in sensory quality compared to ordinary flavored milk.

Formulation Optimization of Tremella fuciformis Ice Cream

2012, 35(3):  17-21.  DOI: 10.15922/j.cnki.jdst.2012.03.005

Asbtract ( )   HTML ( )   PDF (166KB) ( )  

Related Articles | Metrics

Tremella fuciformis was softened and used to develop Tremella fuciformis ice cream. The effects of Tremella fuciformis with different softening treatments, whole milk powder, gelatin and monoglyceride on the overrun, melting resistance and sensory quality of ice cream were investigated. These parameters were optimized using an orthogonal array design. After 35 min of high pressure cooking, Tremella fuciformis became soft and tender, like a sol. The optimal addition amounts of Tremella fuciformis, monoglyceride, gelatin and whole milk powder were separately 5%, 0.4%, 0.2% and 8%. The ice cream produced under these conditions exhibited a homogeneous and exquisite texture, a gentle and smooth taste, a desired taste and a good melting resistance.

Development of Blueberry Yoghurt

2012, 35(3):  22-24.  DOI: 10.15922/j.cnki.jdst.2012.03.006

Asbtract ( )   HTML ( )   PDF (132KB) ( )  

Related Articles | Metrics

Flavored yoghurt was formulated from blueberry juice, yoghurt and a small amount of inulin. Orthogonal array design was used to optimize yoghurt fermentation and formulation based on sensory evaluation. The optimal formulation of flavored yoghurt was 90 g of yogurt obtained by 5 h fermentation at 45 ℃, 5 g of blueberry juice, 0.15% inulin, and 0.15% xanthan gum as a stabilizer. The developed product as an integration of blueberry and yoghurt had abundant nutritional functions, a unique flavor and a light blue color and could be recognized an excellent new functional beverage.

Application of Potato Protein in Ice Cream

2012, 35(3):  25-29.  DOI: 10.15922/j.cnki.jdst.2012.03.007

Asbtract ( )   HTML ( )   PDF (232KB) ( )  

Related Articles | Metrics

Based on sensory score, overrun and melting rate, the formulation of a new low-fat high-protein ice cream with partial substitution of milk powder by potato protein concentrate was optimized by one-factor-at-a-time and orthogonal array design methods. It was found that the optimal ice cream formula was milk powder 6%, soft sugar 8%, sodium carboxymethylcellulose (CMC-Na) 0.2%, starch syrup 2%, potato protein concentrate 50%, monostearin 0.3%, gelatin 0.2%, and dextrin 4%. The ice cream obtained presented homogenous and exquisite texture, gentle smooth taste, unique flavor, excellent melting resistance and desired overrun.

Process Optimization of Production of Walnut Yogurt

2012, 35(3):  30-33.  DOI: 10.15922/j.cnki.jdst.2012.03.008

Asbtract ( )   HTML ( )   PDF (230KB) ( )  

Related Articles | Metrics

Fermentation conditions for producing walnut yoghurt from milk and walnut kernel pieces by both Lactobacillus bulgaricus and Streptococcus thermophilus were investigated. Using one-factor-at-a-time method and an L9(34) orthogonal array design, the optimal fermentation process was determined as follows: 100 mL of milk with 10 g of added sugar was sterilized for 30 min at 63 ℃, inoculated with mixed starter culture at a ratio of 5 g/100 mL, fermented at 35 ℃ for 12 h, added with 5 g of walnut kernel pieces, and then fermented at 5 － 7 ℃ for 24 h. The walnut yoghurt obtained from this fermentation process showed a unique flavor, a high nutritional value and a shelf life of about 10 d at 0－6 ℃.

Analysis & Detection

Determination of Oligosaccharides in Probio+ ,, Malt Extract on Its Effect on Probiotics in Yoghurt

2012, 35(3):  34-38.  DOI: 10.15922/j.cnki.jdst.2012.03.009

Asbtract ( )   HTML ( )   PDF (421KB) ( )  

Related Articles | Metrics

Probio+,, malt extract, which is extracted from barely, is rich in natural nutrients. An HPLC method was used to determine oligosaccharides in Probio+,, malt extract in this study. Meanwhile, the effect of different amounts of Probio+,, malt extract addition on probiotic growth in yoghurt during storage was tested by spread plate method. The results showed that the contents of cellotriose and cellotetraose in Probio+,, malt extract were 10.45μg/mg and 2.79μg/mg, respectively. The addition of Probio+,, malt extract at 3% and sucrose at 4% indicated the best growth promoting effect on probiotics (Bulgaria lactobacillus, Streptococcus thermophilus and Bifidobacterium) in yoghurt, which was better than fructo-oligosaccharide at the same levels.

Detection of β-Lactam Antibiotics and Melamine Residues in Milk by Colloidal Gold Immunochromatographic Assay

2012, 35(3):  39-42.  DOI: 10.15922/j.cnki.jdst.2012.03.010

Asbtract ( )   HTML ( )   PDF (169KB) ( )  

Related Articles | Metrics

A colloidal gold immunochromatographic assay (GICA) was used to detect the residues of β-lactam antibiotics and melamine in milk. The sensitivity, false positive rate (FPR), false negative rate (FNR) and specificity of the method were studied. The results showed that the detection limit of the method was 2 μg/L for penicillin G, 3 μg/L for ampicillin, 4 μg/L for amoxicillin, 6 μg/L for oxacillin, 6 μg/L for cloxacillin, 6 μg/L for dicloxacillin, 20 μg/L for nafcillin, 20 μg/L for cefquinome, 40 μg/L for cefoperazone, 50 μg/L for ceftriaxone, 90 μg/L for ceftiofur, 10 μg/L for cefalonium, and 50 μg/L for melamine. The FPR was less than 5%, and FNR was 0. The specificity was good and there was no cross-reactivity with any other antibiotics in milk. The results of GICA and liquid chromatographic tandem mass spectrometry (LC-MS/MS) were basically consistent. This method is simple, rapid, accurate and stable, and suitable for the on-site rapid detection of β-lactam antibiotics and melamine residues in milk.

Reviews

Research Progress of Yak Milk and Fermented Yak Milk and Their Nutritional Value

2012, 35(3):  43-46.  DOI: 10.15922/j.cnki.jdst.2012.03.011

Asbtract ( )   HTML ( )   PDF (174KB) ( )  

Related Articles | Metrics

Yak milk is produced by yak, a special species living in high attitude, and can be fermented by lactic acid bacteria into yoghurt. Yak milk has a high nutritional value and is rich in amino acids, Ca, Fe, Zn, vitamins, and so on. Yak milk is more abundant in functional fatty acids and proteins compared to common bovine milk and has aroused growing attention. This paper provides a review of various nutrients in yak milk and yoghurt and the probiotic effect of lactic acid bacteria. However, the nutritional value of yak milk products has not been developed and utilized in depth yet. Therefore, further research and development is needed.