Abstract: 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.

Key words: postbiotics; isolation and preparation; exopolysaccharides; bacterial metabolites; dairy products

摘要： 益生菌的健康益处已被广泛研究，但因其生存能力弱和稳定性低等问题限制了益生菌在食品和医药领域的更广泛应用。与益生菌相比，后生元具有存在形式安全和稳定性高等特点，避免了益生菌的限制。2021年，国际益生菌和益生元科学协会将后生元定义为“为宿主提供健康益处的无生命微生物和/或其成分”，包括菌体的组成成分和菌体代谢物，例如无细胞上清液、细胞裂解物、胞外多糖、肽聚糖、短链脂肪酸和有机酸等。不同后生元成分对宿主或产品加工特性具有不同的有益作用，例如在宿主体内能够发挥调节免疫、调节脂代谢、抗炎、抗氧化、抗肿瘤和抗菌等有益活性，在产品加工中能够发挥其抑菌性、稳定性、乳化性等。本文对后生元的分离制备方法及其鉴定方式进行概括，并总结后生元的潜在功能特性，以及在乳制品中的加工特性和潜在应用价值，为后生元在医疗、食品等领域作为良好原料提供理论依据。

关键词: 后生元；分离制备；胞外多糖；菌体代谢物；乳制品