乳酸菌(lactic acid bacteria, LAB)胞外多醣(exopolysaccharides, EPS)係LAB分泌於細胞外之多醣。因其對發酵乳製品之流體性狀、組織、與口感具重要影響，對於促進人體健康，如抗腫瘤、抗氧化、提升免疫力、與促進細胞生長等，亦深具成效，在多數歐洲國家全面進禁止乳製品添加組織促進劑下，爲使發酵乳製品更具健康概念，又能改善產品組織與口感，以EPS生成菌酛，取代傳統添加劑之使用，進行發酵乳製品之製造，爲未來趨勢。LAB爲GRAS菌酛，能分泌出含不同單醣成分與分子大小之EPS，作爲食品添加劑與功能性成分，極具健康概念，市場潛力大。然而，依菌酛、培養基種類與培養條件之不同，LAB會生成不同結構與產量之EPS，進而對食品功能性狀造成影響。爲生產適當結構與大小之EPS以有效提升產品功能性狀，本文將EPS之生物活性及影響EPS結構、產量、黏絲性、穩定度及其與酸酪乳黏度關係之最新研究文獻作詳盡整理，期能對未來EPS利用之相關研究有所助益。
Exopolysaccharides (EPS) of lactic acid bacteria (LAB) are polysaccharides secreted extracellularly from LAB. Those strains have gained considerable attention in the fermented dairy industry because of their potential application as viscosifiers, texturizers, and emulsifying agents, and unique biological properties of antitumoral, antioxidant, and immunostimulatory activities. EPS produced by those food-grade microorganisms with GRAS (Generally Recognized as Safe) status are an important source of natural alternatives to commercial additives of plant or animal origin. Most of those additives used are chemically modified to improve the rheological property of the product and hence are not allowed in most European Union countries. Since the popularity of nature food products without any additives has increased, the use of EPS producing LAB could result in a safe, natural, and healthy end-product with enhanced texture and improved stability, which may have an important impact on the development of novel products. Various LAB strains, types of incubation media, and incubation conditions affect structure and yield of EPS and subsequent influence in functional properties when incorporated into a food matrix. This article provides an overview of structure, yield, ropiness, and stability of EPS and its effect on viscosity of yogurt for the need of further studies on EPS.
