The enzymatic hydrolysate of Zhongdian yak milk casein was fractionated by ultrafiltration into two fractions: molecular mass > 3 kDa and < 3 kDa. The cell proliferation activity and antioxidant activity of the two fractions were determined. The bioactive peptides derived from yak milk casein were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), bioinformatics and molecular docking. The results showed that the proliferation rate of RAW264.7 cells was above 80% in the presence of either the molecular mass > 3 kDa or < 3 kDa fraction. Both fractions had the ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) cation radical. The cell proliferation and free radical scavenging activity of the molecular mass < 3 kDa fraction were better than those of the > 3 kDa fraction. A total of 895 peptides were identified from the molecular mass < 3 kDa fraction, of which 96 were known bioactive peptides, mainly antioxidant peptides (39.6%) and angiotensin-converting enzyme inhibitory peptides (30.2%), indicating that Zhongdian yak casein is an important source of bioactive peptides. Based on their activity and hydrophobicity, antioxidant peptides GYF and RPW were selected from the predicted 20 potential antioxidant peptides. The results of molecular docking showed that the binding energies of GYF and RPW with ABTS cation and DPPH radicals were all negative, indicating that they had binding potential and exerted antioxidant activity mainly by forming hydrogen bonds and hydrophobic interactions.

Probiotics have been extensively researched for their health advantages, but their poor stability and viability prevent them from being used in foods and medicine on a larger scale. Compared with probiotics, postbiotics have the advantages of higher safety and stability in its existing form, which avoids the limitation of probiotics. In 2021, the International Scientific Association for Probiotics and Prebiotics defined postbiotics as preparation of inanimate microorganisms and/or their components that confers a health benefit on the host including bacterial components and metabolites, such as cell-free supernatant, cell lysate, extracellular polysaccharide, peptidoglycan, short-chain fatty acids, and organic acids. Postbiotic components exhibit varying beneficial effects on the host, such as regulating immunity and lipid metabolism, anti-inflammatory, antioxidant, anti-tumor, and antibacterial activities, and on product processing as an antibacterial, stabilizing and emulsifying agent. This paper provides an overview of the methods for separating, preparing and identifying postbiotics. It also summarizes the potential functional characteristics of probiotics, their processing characteristics in dairy products and their potential application value. This review provides a theoretical basis for the application of postbiotics as good raw materials in the medical and food fields.

To quickly and accurately evaluate the risk of ochratoxin A (OTA) pollution in dairy products, a method to detect fungi capable of producing OTA in dairy products was developed using gene probe scanning technology. According to the elucidated biosynthesis pathway of OTA, the halogenase gene related to OTA production was selected to design degenerate primers to establish a polymerase chain reaction (PCR) method for the detection of OTA-producing fungi. One OTAproducing strain (Aspergillus ochraceus) and five strains not able to produce OTA (Aspergillus cristatus, Aspergillus flavus, Fusarium moniliforme, Issatchenkia terricola, and Saccharomyces cerevisiae) were selected to test the PCR method. It was found that DNA from the OTA-producing strain but not the non-OTA producers could be amplified by PCR. Moreover, this method had high accuracy and sensitivity for detecting polluted dairy products.

In this study, the complete antigens of fipronil and its analogue were synthesized using glutaraldehyde (GA) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) as a cross-linker, respectively, and were identified by ultraviolet absorption spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). BALB/c mice were immunized with fipronil-bovine serum albumen to obtain hybridoma cell 3F6. Monoclonal antibodies were prepared by inducing ascites in mice. An enzyme-linked immunosorbent assay (ELISA) was developed and evaluated to determine fipronil in milk. The results showed that the concentration of the prepared monoclonal antibody, belonging to the IgG1 subclass, was 8.5 mg/mL, and the titer was 2.0 × 106. The cross-reaction rates with fipronil-desulfinyl, fipronil sulfone and fipronil sulfoxide were 9.21%, 14.02% and 21.46%, respectively. The recoveries of fipronil in spiked milk were 87%–118%, and the coefficient of variation for precision was less than 15%. In conclusion, this method is highly accurate and precise.

Constructing an efficient and safe producer strain is a prerequisite for biosynthetic production of 2’-fucosyllactose. The number and technical content of recent patents on 2’-fucosyllactose biosynthesis applied for in China are reviewed in this paper, indicating that over 80 percent of the patents focused on the construction of recombinant strains by optimizing the metabolic pathways, overexpressing 2’-fucosyllactose biosynthesis-related enzyme genes, and developing more safe and efficient host strains. However, after a review of China’s patented technologies in this regard, we found that research on the biosynthetic production of 2’-fucosyllactose in a pilot scale or above is weak, and there is a lacuna in utility and industrially oriented patented technologies, which will bottleneck the 2’-fucosyllactose biosynthesis industry in China.

Superoxide dismutase (SOD) is extensively present in milk and dairy products as as important metalloenzyme for protecting organisms against aging. SOD plays an important role in the health-beneficial effect of dairy products. Herein we review recent advances in studies on the biological activity and processing stability of SOD in dairy products.

As cow milk quality and safety problems appeared frequently in recent years, goat milk has gained more attention from scholars and consumers and has been increasingly accepted by consumers for its high nutritional value. This article reviews the nutritional and health advantages and deodorization of goat milk, and explores the market prospects for goat milk and related products.

The stability of caprine casein directly determines the quality of caprine proteins. Understanding the stability of caprine casein is necessary to obtain high-quality goat milk. This article overviews the current status of China’s goat milk industry, and makes a brief description of the properties of caprine casein as well as factors affecting its stability. Moreover, the effect of temperature, pH, inorganic salt ions, food additives and ultrahigh pressure treatment on the stability of caprine casein is reviewed. Controlling the stability of caprine casein is of great significance for the development of goat milk products.