Table of Content

01 May 2022, Volume 45 Issue 3

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Basic Research

Effects of Lactobacillus plantarum Isolated in Our Laboratory on the Quality and Functional Properties of Goat Milk Yogurt

WANG Weizhe, REN Rong, HUI Yuanyuan, ZHANG Fuxin, WANG Bini

2022, 45(3):  1-8.  DOI: 10.7506/rykxyjs1671-5187-20220318-013

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In order to improve the flavor and quality of goat milk yogurt and enhance its functional value, Lactobacillus plantarum JS5 and JS19, isolated from Jiangshui, a traditional Chinese fermented vegetable food, were used for goat milk fermentation. The physicochemical properties, textural characteristics, and functional properties of goat milk yogurt were evaluated. The results showed that mixed-culture fermentations with each isolate and a commercial starter culture improved the water-holding capacity and apparent viscosity of goat milk yogurt, reduced its hardness and gumminess and promoted the release of acetaldehyde and diacetyl. The rate of cholesterol degradation (up to 36.62%) in goat milk yogurt containing Lactobacillus plantarum JS5 was significantly higher than that in the control group (P < 0.05). Goat milk yogurt containing Lactobacillus plantarum JS19 showed stronger antioxidant capacity in vitro, which could scavenge 70.58% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and had a ferric ion reducing antioxidant power (FRAP) value of 32.03 μmol ferrous sulfate equivalent/L on the first day of storage. Therefore, both strains are suitable for goat milk fermentation.

Processing Technology

Effects of Different Sterilization Processes on the Quality of Extended Shelf-Life Milk

REN Lu

2022, 45(3):  9-13.  DOI: 10.7506/rykxyjs1671-5187-20211228-014

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The effects of traditional high-temperature sterilization, direct steam infusion and membrane filtration combined with pasteurization on the quality of extended shelf-life (ESL) milk were compared by measuring microbial indexes, shelf life, percentage loss of lactoferrin (LF) and immunoglobulin G (IgG) and furosine content. The process parameters for steam immersion sterilization and membrane filtration combined with pasteurization were optimized. The results showed that compared with traditional high temperature sterilization, direct steam infusion (147 ℃/0.09 s) resulted in a longer shelf life, more stable quality and lower furosine content and retained lesser amounts of active substances. Membrane filtration combined with 72 ℃/15 s sterilization retained more active substances such as LF and IgG. However, this process has higher requirements for storage temperature. The storage temperature needs to be lower than 6 ℃ to ensure the stability of product quality.

Analysis & Detection

Comparative Analysis of Similarity of Fatty Acid Composition between New Generation of Infant Formula and Breast Milk

JIA Hongxin, JIE Liang, SU Miya, CHEN Wenliang, LIU Haian

2022, 45(3):  14-18.  DOI: 10.7506/rykxyjs1671-5187-20211214-011

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Breast milk is the most ideal natural food for infants and the gold standard for the development of infant formula (IF). Accurately simulating the nutritional components of breast milk is an important means to improve IF. In order to better simulate breast milk lipids, a new generation of IF was developed based on the reported breast milk data, and then the total fatty acids and sn-2 fatty acids in breast milk and the new generation of IF were comparatively analyzed. The results showed that the new generation of IF and human milk were highly similar in total fatty acids and sn-2 fatty acids (the similarity coefficients were > 85% and > 70%, respectively). In conclusion, the new generation of IF can accurately simulate the total fatty acids and sn-2 fatty acids in human milk.

Analysis of the Pollution Status of Eight Harmful Elements in Commercial Milk Fan and Milk Cake

CHEN Junxiu, LI Jie, LIU Ling, RAN Yali, LI Yi, LI Wenting

2022, 45(3):  19-23.  DOI: 10.7506/rykxyjs1671-5187-20220427-024

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To investigate the pollution status of eight harmful elements in milk fan and milk cakes. Milk fan and milk cake were sampled from representative farmers’ markets and supermarkets in some districts or counties of a certain city. The samples were digested by a wet digestion method using graphite, and eight harmful elements including arsenic, lead, mercury, cadmium, chromium, boron, aluminum and barium in the digested samples were simultaneously detected by inductively coupled plasma mass spectrometry (ICP-MS) and quantified by an internal standard method. Neither milk fan nor milk cake samples were found to be contaminated by mercury or cadmium, and the contamination levels of boron, arsenic, barium and lead was relatively low; however, the milk fan samples were seriously polluted by aluminum and chromium, and the contamination level of barium in milk cakes was relatively high. Both milk fan and milk cake samples contained chromium, barium and lead, and the contamination level of the former was higher than that of the latter. Accordingly, relevant departments should strengthen supervision over milk fan and milk cake workshops, standardize the production processes, strictly control the potential pollution links, and strengthen supervision over pollution in the production process to ensure product quality and safety.

Determination of 1-Oleic-2-palmitic-3-linoleic acid triglyceride in Infant Formula

LIU Chunxia, DUAN Guoxia, LIU Lijun, CHEN Sumin, LI Cuizhi, LÜ Zhiyong

2022, 45(3):  24-28.  DOI: 10.7506/rykxyjs1671-5187-20220330-015

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A gas chromatographic (GC) method for the determination of 1-oleic-2-palmitic-3-linoleic-triglyceride (OPL) in milk powder was established. The samples were extracted with ether and petroleum ether, and the extract was concentrated to near dryness, re-dissolved in n-heptane, separated on a CP-TAP CB elastic quartz capillary column, detected by a hydrogen flame ionization detector, and quantified by an external standard method. The column temperature was programmed to rise. The inlet temperature was set at 330 ℃. The samples (1.0 μL) were injected using the split mode (1:10). The detector temperature was set at 360 ℃. Nitrogen was used as the carrier gas. The makeup flow rate (nitrogen) was 25 mL/min. The recovery of OPL from spiked milk powder at 1–6 g/100 g ranged from 95.2% to 101.9%, and the relative standard deviations (RSDs) for precision ranged from 1.289% to 1.998%. The limit of detection (LOD) and limit of quantitation (LOQ) of the proposed method were 0.2 and 1.0 g/100 g, respectively. This method, therefore, is simple, accurate, repeatable, and suitable for the determination of OPL in milk powder.

Packaging & Storage

Preservative Effect of a Pickering Emulsion Containing Antimicrobial Peptide MOp2 from Moringa oleifera Seeds on Milk Cake

ZOU Lirong, HUANG Zhiyuan, DONG Wenming, WANG Xuefeng

2022, 45(3):  29-33.  DOI: 10.7506/rykxyjs1671-5187-20220302-012

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In order to extend the shelf life of milk cake, a Pickering emulsion containing antimicrobial peptide MOp2 from Moringa oleifera seeds was applied as preservative to milk cake. In this experiment, the preservative effect of the Pickering emulsion on milk cake was determined by measuring peroxide value, texture properties, total viable count, coliform count, color difference and sensory attributes. The results showed that Escherichia coli was detected in the vacuum packaging group (control) after 28 days of storage, and the count of E. coli exceeded the safety limit after 35 days. The total viable count, peroxide value (POV), and color difference was significantly higher than those of the experimental group coated with the Pickering emulsion. The experimental group remained unspoiled for 42 days. Sensory quality remained stable during the first 35 days of storage, total viable count increased slowly, and E. coli was not detected in the experimental group. Significant differences in texture properties between the two groups were observed starting from the 21th day of storage. Sensory and physicochemical evaluation showed that compared with the control group, the Pickering emulsion prolonged the storage life of milk cake by one week, indicating its good preservative effect.

Reviews

Advances in Research and Application of Probiotics in Ameliorating Rheumatoid Arthritis

YANG Yang, LIU Zhenmin, LI Nan

2022, 45(3):  34-38.  DOI: 10.7506/rykxyjs1671-5187-20210909-058

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Rheumatoid arthritis is an autoimmune disease that threatens human health all over the world. Rheumatoid arthritis is closely related to intestinal microbial balance. Probiotics have been demonstrated to have the potential for treating rheumatoid arthritis as they can play an important role?in?improving gut microbiota disorder and restoring normal gut microbiota.?This?paper reviews the pathogenesis of rheumatoid arthritis and the changes in the gut microbiota of patients with rheumatoid arthritis, and summarizes research studies on the application of probiotics in alleviating rheumatoid arthritis, in order to provide a basis for further clinical trials and application of probiotics.

Progress in Research on the Role of Bioactive Components of Breast Milk in Infant Immune Health

JIE Liang, JIA Hongxin, CHEN Wenliang, SU Miya

2022, 45(3):  39-43.  DOI: 10.7506/rykxyjs1671-5187-20210909-057

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Recognized as the gold standard of infant nutrition and the best food for infants, breast milk offers many benefits in addition to nutrition, such as immune protection, due to its multiple bioactive components. This paper reviews the effect of lactoferrin, oligosaccharides, nucleotide, 1,3-dioleic acid-2-palmitic triglyceride and probiotics as bioactive components in breast milk on infant immune health, and it analyzes optional ingredients for 11 commercial brands of infant formula in order to provide a theoretical basis for the selection of optional components in infant formula.

A Review on Techniques for Separation of Functional Proteins from Milk

ZHANG Libo, ZHANG Le, LIANG Yuxin, DOU Qingzhe, LI Chun

2022, 45(3):  44-50.  DOI: 10.7506/rykxyjs1671-5187-20220427-023

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Functional proteins in milk, including α-lactalbumin, β-lactoglobulin, lactoferrin, lactoperoxidase, β-casein and milk fat globule membrane protein, have been reported to have important physiological functions and play important roles in human health and thus, they have attracted widespread attention from researchers and manufacturers. However, there is a bottleneck for the development of techniques for the separation of functional proteins from milk, which restricts their industrial production and practical application. In this paper, the mature techniques for the separation and purification of six functional proteins from milk are summarized, with special reference to their application conditions and experimental scale, in order to provide a basis the separation and purification of functional proteins from milk in laboratories and factories and the development of new functional milk protein products.

A Review of Food Safety Control and Management in the Production Process of Dairy Products

WEN Guoyan, WANG Yanlong, FU Yunshuang, ZHAO Zhen, WAN Peng, LI Cuizhi, LÜ Zhiyong

2022, 45(3):  51-57.  DOI: 10.7506/rykxyjs1671-5187-20211120-006

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Dairy products are favored by more and more consumers because of their rich nutrients and good taste, and have become an important part of consumers’ dietary structure. At the same time, the food safety of dairy products has become the focus of consumers’ attention. Therefore, controlling dairy food safety is a top priority for every dairy company. This article expounds on the food safety control measures for ensuring quality and safety in each link of the dairy product production process. To ensure the safety of milk sources, pasture construction and management and risk control during breeding activities need to be considered. The control of raw and auxiliary materials needs to be carried out by considering the acceptance system, storage of raw and auxiliary materials, and upstream supplier management and control. The control of the production process needs to be carried out from the aspects of personnel, equipment, ingredient and environmental management. In addition, this review highlights the importance of big data technology in dairy food safety risk analysis. We expect that this review will be helpful to relevant enterprises in improving their work on food safety management.