The industrial application of free enzyme is limited due to its high cost, poor operational stability and difficult reuse. Immobilization on carrier is an effective way to overcome the limitation. Nanozyme immobilization technology has emerged in the past 10 years, which is an emerging technology with great potential. At present, immobilized enzymes have been widely used in several fields such as food, medical treatment, and environmental treatment. This article systematically summarizes the latest progress in the research and application of immobilized enzymes based on three new nanomaterials (protein-inorganic hybrid nanoflowers, metal organic frameworks and nanogels), comprehensively compares the advantages and disadvantages of the three nanomaterials, analyzes and summarizes their respective applicable enzymes, and finally points out that cascade enzyme immobilization and the development of new immobilized materials are the future trend for the development of immobilized enzymes.

Kefir is a mildly alcoholic dairy beverage made from cow’s, goat’s or sheep’s milk fermented with kefir grains, which mainly consist of lactic acid bacteria, acetic acid bacteria and yeast. Due to its unique flavor and taste, as well as outstanding probiotic effects, kefir is increasingly attracting attention from consumers. As a natural starter culture, kefir grains have a complex structure and rich microbial composition. At present, fermentation with a starter culture consisting of microbial strains isolated from kefir grains is mainly used for the industrial production of kefir. This article reviews the microbial composition of kefir grains, the impact of kefir grains from different regions and raw materials on microbial diversity during the kefir fermentation process, and summarizes the current progress in research on flavor substances in kefir.

Lactic acid bacteria, a group of microorganisms that can ferment sugars into lactic acid, are widely used in the production of yogurt products. Different lactic acid bacteria exhibit different fermentation characteristics, which not only alter the physicochemical properties of yogurt but also have a significant impact on its nutritional value. This paper reviews the relationship between yoghurt products and microbial metabolism with a special focus on the role and influence of microorganisms in yoghurt making. The production of yogurt relies on the fermentation of specific microorganisms, such as lactic acid bacteria, which not only convert lactose to lactic acid, change the pH and texture of yogurt, but also synthesize a range of bioactive substances, such as vitamins, thereby having a positive impact on the health of consumers. This paper summarizes recent advances in understanding the fermentation mechanism of yoghurt, revealing the contribution of microbial diversity to product characteristics. In addition, this paper also discusses the health benefits of microbial metabolites in yogurt, including improving intestinal health and enhancing immunity. It is hoped that this review will provide a scientific basis and technical guidance for the research and development of yogurt products.