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Table of Content

    01 July 2025, Volume 48 Issue 4
    Basic Research
    Effects of Selenium Biotransformation on Composition and Quality Properties of Goat Milk Casein
    MA Xi, LIU Qingqing, CHEN Jin, LI Bin, ZHANG Ying, CAO Wei, ZHAO Donglin, SUN Qiubo, PENG Deju
    2025, 48(4):  1-9.  DOI: 10.7506/rykxyjs1671-5187-20250320-021
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    This study investigated the effects of selenium biotransformation on the composition, structure, functional properties, and in vitro antioxidant activity of goat milk casein, as well as its gastrointestinal digestibility properties and selenium bioavailability. The results showed that the total selenium content in selenium-enriched goat milk casein was 498.21 μg/100 g, with organic selenium comprising up to 99.92%. Selenium transformation did not induce significant changes in the major composition of goat milk casein, and although the secondary structure of the protein and certain functional properties exhibited minor alterations, the overall stability was maintained. The antioxidant activity of selenium-enriched goat milk casein was positively correlated with protein concentration and selenium content. Upon reaching a specific threshold of protein concentration, its antioxidant capacity was significantly superior to that of ordinary goat milk casein. In vitro simulated gastrointestinal digestion showed that selenium transformation did not significantly influence the digestibility of goat milk casein, with its selenium bioavailability reaching as high as 90.75%. Moreover, the antioxidant activity of the digestion products was further enhanced and significantly better than that of the non-selenium-enriched group. Comprehensive analysis revealed that selenium-enriched goat milk casein possessed a high organic selenium content, good protein structure and functional stability, superior antioxidant activity, favorable digestion characteristics, and high selenium bioavailability, thereby positioning it as a promising high-value-added functional selenium-enriched milk protein product.
    Characterization of Structural Changes in Heat-Induced Whey Protein Isolate-Agaricus bisporus Polysaccharide Composite Hydrogel by Simultaneous Rheology-Fourier Transform Infrared Spectroscopy
    SU Ying, HE Yumeng, LI Yilong, XIANG Huiyu, TAO Weibing, WU Xiaoxue, WANG Jing, WANG Chenhao, SUN Xiaomeng
    2025, 48(4):  10-20.  DOI: 10.7506/rykxyjs1671-5187-20250120-008
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    Heat-induced polymerized whey protein (PWP) gels from whey protein isolate have limited application due to their high brittleness, but addition of polysaccharides in PWP gels can significantly improve their properties. Agaricus bisporus polysaccharide (ABP), as an anionic polysaccharide, exhibits excellent biological activities, but the formation mechanism of its composite hydrogels with PWP remains unclear. In this study, the effect of ABP concentration (0–4 g/100 mL) was investigated on physicochemical properties of PWP-ABP composite hydrogels including average particle size, zeta potential, surface hydrophobicity, intrinsic fluorescence spectrum and free sulfhydryl group content. The results demonstrated that as the ABP concentration increased, the average particle size of PWP-ABP composite hydrogels significantly increased from (76.22 ± 7.43) to (145.93 ± 8.20) nm (P < 0.05), and the absolute value of zeta potential rose from (35.60 ± 2.64) to (45.20 ± 1.40) mV, indicating that ABP enhanced the stability of the composite hydrogels through electrostatic repulsion. Additionally, the surface hydrophobicity decreased remarkably, and the free sulfhydryl group content significantly decreased (P < 0.05), confirming that ABP altered the tertiary structure of PWP via hydrophobic interactions and disulfide bond crosslinking. Synchronous rheology-Fourier transform infrared spectroscopy analysis revealed that ABP induced a red shift in the amide A region (3 600–3 200 cm-1) of PWP, suggesting enhanced hydrogen bond formation; the fluctuations in the amide I band (1 625 cm-1) were attributed to electrostatic interactions. Molecular docking analysis showed that ABP binds to β-lactoglobulin via hydrogen bonds and two-dimensional correlation spectroscopy further validated the changes in O–H stretching vibrations. In conclusion, ABP optimizes the gel network structure of PWP through hydrophobic interactions, hydrogen bonds and electrostatic interactions, providing a theoretical foundation for developing functional food gel systems.
    Processing technology
    Process Optimization and Quality Analysis of Sheep Milk Cake Using Dregea sinensis Hemsl. Coagulant
    LUO Haowen, ZHANG Xianglin, LI Qiqi, WANG Xingrun, ZHAO Lingfan, YANG Yufei, ZHANG Xu, GE Wupeng
    2025, 48(4):  21-27.  DOI: 10.7506/rykxyjs1671-5187-20250228-015
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    This study aimed to investigate a novel technology for producing sheep milk cake using Dregea sinensis Hemsl. extract as a new coagulant. The processing conditions were optimized using one-factor-at-a-time and orthogonal array design methods. The sensory characteristics, physicochemical properties, color, texture characteristics and microstructure of the milk cake were evaluated in comparison with those of traditional acid-coagulated milk cake. The results showed that the optimal processing conditions, determined based on sensory score and yield, were as follows: curdling temperature 80 ℃, Dregea sinensis Hemsl. coagulant (DSHC) concentration 22.5%, calcium chloride concentration 0.015%, and pressing for 2 h at 3 kg/cm2. The sensory score of the milk cake prepared under the optimized conditions was 83.25 ± 1.04, which was higher than that of acid-coagulated milk cake. The new milk cake contained (32.12 ± 0.39)% protein, (20.45 ± 0.25)% fat and (46.33 ± 0.41)% moisture, and its calcium, phosphorus and selenium contents were significantly higher than those of acid-coagulated milk cake (P < 0.05). Texture profile analysis indicated that the hardness, gumminess and chewiness were significantly better than those of the control group (P < 0.05). The gel network of the DSHC milk cake was more homogeneous and had better water retention capacity. These findings indicate that the novel coagulant DSHC demonstrates potential to replace traditional acid-induced coagulation processes. The product had a uniform color, good taste and strong milky flavor. Therefore, this process can serve as a new technology for the production of sheep milk cake.
    Analysis & Detection
    Microbial Identification and Analysis of the Production Environment of Infant Formula in Fujian Province in 2024
    QIU Xibin
    2025, 48(4):  28-35.  DOI: 10.7506/rykxyjs1671-5187-20250210-011
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    Objective: To investigate the microbial community composition and structure of the processing workshop of infant formula in Fujian province in 2024, to reveal the microbial diversity present in the workshop as well as the changes in the distribution of microorganisms among different functional zones, and to unveil the drug resistance of the isolates. Methods: A stratified random sampling strategy was employed to collect surface microbiota, airborne planktonic bacteria and sedimentary microbes from the selected manufactures by aseptic swabbing, six-stage Andersen air sampling, and plate exposure methods, respectively. The purified isolates were analyzed by 16S rDNA gene sequencing and multi-sequence alignment and phylogenetic tree construction were carried out using the MEGA software. To ensure taxonomic accuracy, the VITEK? 2 Compact fully automatic microbial identification system was utilized for physiological and biochemical characterization, and phenotypic validation was performed by referring to the latest Bergey’s manual of systematic bacteriology. A dual verification framework integrating molecular and traditional phenotypic identification was thereby established. Antimicrobial susceptibility testing was performed using standardized protocols, and based on the data obtained, a heatmap was generated. Results: A total of 355 isolates were obtained, belonging to 19 genera. Out of these, 61.1% were Gram-positive bacteria, and 38.9% were Gram-negative bacteria, Staphylococcus, Bacillus, and Pseudomonas being the major ones, accounting for 72.95% of the total collected strains. Among them, Staphylococcus has the highest distribution rate, accounting for 33.80% of all isolated strains The phylogenetic analysis and spatial distribution pattern of Staphylococcus revealed personnel movement and material handling to be the principal contamination vectors. Antimicrobial susceptibility testing demonstrated that coagulase-negative staphylococci (CoNS) showed 100% susceptibility to teicoplanin, vancomycin and linezolid and 20%–90% susceptibility to penicillin G (benzylpenicillin), erythromycin, methicillin and clindamycin. Some of the environmental isolates showed multi-drug resistance. Conclusion: Staphylococcal species were the dominant microbial population in the infant formula production environment, with workshop operators being their largest vector. The identification of antimicrobial-resistant isolates underscores the need for enhanced personnel sanitation and air purification to reduce the risk of microbial contamination.
    Reviews
    Research Progress on the Effect of Sialyllactose on Bifidobacterium
    XIA Zixian, LIU Rui, GUAN Xiaoyan, WANG Xiaohong, LÜ Youyou
    2025, 48(4):  36-44.  DOI: 10.7506/rykxyjs1671-5187-20250327-027
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    Human milk oligosaccharides (HMOs) are important nutritional components in breast milk, and sialyllactose (SL) is one of the core members of HMOs. HMOs play an important role in regulating the gut microbiota of infants, especially in the reproduction and metabolic regulation of the dominant gut microbiota in early life-Bifidobacterium. The sources of SL are diverse and there are various methods available to prepare it, providing multiple alternative pathways for its industrial application. However, the interaction mechanism between SL and Bifidobacterium is complex, and there are still many difficulties that need to be overcome, which affects the combined application of SL and Bifidobacterium in the food and other industries. Therefore, this review covers three aspects: the formation pathways of SL, the carbohydrate uptake behavior and HMOs metabolism of Bifidobacterium, and the mechanism of SL on Bifidobacterium, focusing on the latest advances in related fields. The aim is to provide scientific reference for promoting the application of SL and Bifidobacterium in the development of breast milk substitutes and functional foods.
    Research Progress on the Preparation and Biological Activities of Milk Protein-derived Peptides
    BO Zhihang, WEI Jiazhou, SU Quan, LI Chunmei, LIU Libo, ZHANG Guofang, LI Chun, CHEN Zhicheng
    2025, 48(4):  45-53.  DOI: 10.7506/rykxyjs1671-5187-20250228-013
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    As an important functional protein resource in dairy products, milk protein has become a research hotspot due to its excellent nutritional value and multiple biological activities. Recent studies have made breakthrough progress in the preparation and functional analysis of milk protein-derived peptides. There are various bio-processing methods to precisely release bioactive peptides with specific functions from milk protein, such as directed enzymatic hydrolysis and controlled fermentation. These active components demonstrate significant health benefits in antioxidant defense, pathogen inhibition, immune homeostasis regulation, and blood pressure control. This paper systematically reviews the technologies for the preparation of milk protein-derived peptides, including enzymatic hydrolysis, microbial fermentation, chemical synthesis and computer simulation and prediction techniques, and conducts a comparative analysis the effectiveness and characteristics of these technologies. Furthermore, it elucidates the mechanisms by which milk protein-derived peptides exert their biological activities and their bioavailability, and evaluates their potential for application in functional foods and pharmaceutical formulations. By integrating existing research findings, this review provides a scientific basis for optimizing the production process of milk protein-derived peptides and expanding their application scenarios, thereby promoting their industrial development.
    Review of Factors Influencing the Stretchability of Mozzarella Cheese
    YAN Puwei, ZHANG Miao, MI Lan, WANG Ying, SONG Xuemei, ZHANG Yan
    2025, 48(4):  54-61.  DOI: 10.7506/rykxyjs1671-5187-20250113-004
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    Mozzarella cheese is a white, lightly flavored, stretchable cheese produced through a hot-stretching process, which endows the product with unique functional properties such as stretchability and meltability. Stretchability is defined as the ability of the cheese to form long, thin bundles of fibers without breaking, and it is a critical quality characteristic of Mozzarella cheese and also an important indicator for quality evaluation, determining its marketability and price. This paper delves into the formation mechanism of stretchability in Mozzarella cheese and outlines the factors affecting it such as the content and structure of casein micelles (including particle size and monomer composition), the content and forms of calcium ions, the size of milk fat globules, and blanching and stretching conditions (acidification, blanching, and stretching). The relationship between nutrient contents of raw milk and cheese stretchability is also discussed. This review provides theoretical guidance for the development and utilization of milk resources in China and offers a scientific basis for the production of Mozzarella cheese with excellent stretching characteristics. Furthermore, a brief analysis is made of the current situation and problems of Mozzarella cheese production in China in order to provide a reference for the development of the Mozzarella cheese industry.
    Research Progress in the Structure, Biological Function and Extraction of Bovine Lactoferrin
    KONG Zihan, ZHANG Linfang, MENG Xiangchen, LIU Fei
    2025, 48(4):  62-46.  DOI: 10.7506/rykxyjs1671-5187-20250313-019
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    Bovine lactoferrin (BLF), as an important iron-binding glycoprotein in mammalian milk, has a broad application prospect in the fields of food, medicine and nutraceuticals. This article briefly introduces the structural characteristics of BLF, and systematically summarizes its various biological functions including antibacterial, immunomodulatory, antioxidant, antiviral, antitumor and its mechanism of action. Meanwhile, it reviews the techniques currently used to extract BLF with special reference to their advantages and disadvantages. Finally, the current research hotspots and prospects of BLF are analyzed. This review provides a theoretical reference for the in-depth understanding of the biological properties of BLF and for its industrial development, thereby advancing its application in functional foods and foods for special medical purposes
    Research Progress on the Modulation of Lipid Metabolism by Bovine Milk Phospholipids
    ZHOU Lihong, ZHANG Tong, HUANG Jinlian
    2025, 48(4):  70-59.  DOI: 10.7506/rykxyjs1671-5187-20250320-020
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    Milk phospholipids have become a research hotspot due to their unique biological activity, especially significant potential in regulating liver lipid metabolism, body fat distribution, and intestinal microbiota balance. This article provides a systematic review of their classification, composition, structural characteristics and regulatory mechanisms on lipid metabolism, highlighting their potential application value. Milk phospholipids are mainly derived from milk fat globules and nanovesicles, the main components being glycerophospholipids and sphingophospholipids. Their contents and composition are both influenced by cow breeds, lactation stages, and processing methods. They are amphiphilic, can form a stable emulsion system, and have multiple beneficial functions such as antioxidant, anti-inflammatory, and promoting neural development. Cow’s milk phospholipids regulate liver lipid metabolism through the following pathways: 1) inhibiting key enzymes involved in lipid synthesis (such as acetyl coenzyme A carboxylase), 2) activating lipid degradation pathways (such as peroxisome proliferators-activated receptor α-mediated β-oxidation), 3) regulating lipid transport related genes (such as SR-BI), and 4) indirectly regulating the release of free fatty acids through the aggregation and digestion characteristics of fat globules. Bovine milk phospholipids regulate body fat in both a dose- and model-dependent manner. Supplementation with milk fat globule membrane (MFGM) during childhood can prevent adult body fat accumulation. In the context of a high-fat diet, MFGM supplementation in adults may increase visceral fat content, but enhance energy expenditure and alleviate obesity by promoting the browning of white adipose. The interaction of MFGM with the gut microbiota is one of its important mechanisms, which improves intestinal barrier function, reduces the risk of endotoxemia, and indirectly regulates metabolic inflammation and lipid homeostasis by increasing the abundance of beneficial bacteria such as Bifidobacterium and Bacteroidetes and inhibiting Gram-negative bacteria. Scavenger receptor class B type I (SR-BI) may play a central role in the bioactivities of bovine milk phospholipids. It activates the phosphatidylinositol 3-kinase protein kinase B signaling pathway by binding to anionic phospholipids, regulating lipid uptake and storage genes. High-fat diet up-regulates SR-BI expression, promoting lipid deposition. In this context, bovine milk phospholipids may exacerbate fat accumulation, reflecting the complexity of their mechanism of action. Although the effect of bovine milk phospholipids is significant in animal models, their clinical translation faces challenges such as lack of standardization of the dose-response relationship and physiological differences between humans and animals. Future research needs to combine multi-omics techniques and clinical trials to explore personalized intervention strategies to develop functional foods based on cow’s milk phospholipids aiming to address the global burden of metabolic diseases such as obesity and non-alcoholic fatty liver disease. In summary, bovine milk phospholipids regulate lipid metabolism through multiple targets and mechanisms, showing broad application prospects. However, their mechanisms of action and clinical application need further investigation.
    Research Progress on Indicator Selection and Predictive Modeling for Shelf-Life Determination of Dairy Products
    WAN Longyu, TU Wen, ZHANG Jiaxin, WANG Huabing, WANG Xu, ZHAO Qianyu, QU Bo, JIANG Yujun, ZHAO Feng
    2025, 48(4):  79-85.  DOI: 10.7506/rykxyjs1671-5187-20250303-017
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    Extending the shelf life of dairy products is of critical importance for the development of the dairy industry. Globally, dairies are actively exploring innovative business growth strategies to address the rising consumer demand for high-quality dairy products while simultaneously improving the economic benefits and promoting the environmental sustainability of processed foods within the supply chain. The system of dairy products is very complex, and during the storage period, the physicochemical properties of nutrients and nutrient-nutrient interactions are complicated, highly variable, and susceptible to deterioration when the external environment changes. This review focuses on key quality indicators of dairy products, such as lipid oxidation, non-enzymatic browning, and significant environmental factors. By systematically selecting appropriate indicators and developing robust shelf-life prediction models, a scientific foundation is laid for the rapid and precise development of shelf-life models. These efforts ultimately support the sustainable development of the dairy industry.