Yeast extracts are the concentrates of the soluble fraction of yeast and more particularly Saccharomyces cerevisiae. As food ingredients, yeast extracts are described for their nutritional composition and flavoring properties. They are produced principally from autolysis, but in some cases, acid or exogenous enzyme preparations are added. The main nutritional components of yeast extracts include partly hydrolyzed protein with 35–40% of free amino acid, and they also contain B vitamins and some trace elements. As flavoring ingredients in foods, they provide diverse flavors depending on the methods used for their production. These flavors include meaty, kokumi, umami, and salty taste along with taste masking properties. Yeast extracts are a source of amino acids, including glutamic acid, with a content of about 5% and 10% w/w free and total glutamate, respectively. Yeast extracts have the capacity to induce the umami taste, the flavoring effect of monosodium glutamate (MSG), when providing glutamate at an amount below 1% in foods, i.e., below the amount required for pure MSG. The latest studies indicate that they can also be used as sources of bioactive substances in functional foodstuffs and dietary supplements.

中文翻译：

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酵母提取物：营养和调味食品成分

酵母提取物是酵母（尤其是酿酒酵母）可溶级分的浓缩物。作为食品成分，描述了酵母提取物的营养成分和调味特性。它们主要由自溶产生，但在某些情况下，添加酸或外源酶制剂。酵母提取物的主要营养成分包括部分水解的蛋白质和35-40％的游离氨基酸，它们还含有B族维生素和一些微量元素。作为食品中的调味成分，根据其生产方法，它们可提供多种风味。这些风味包括肉味，kokumi，鲜味和咸味以及掩味性能。酵母提取物是氨基酸的来源，包括谷氨酸，游离和总谷氨酸的含量分别为约5％和10％w / w。酵母提取物具有诱导鲜味的能力，即，低于纯味精所需的量。最新研究表明，它们也可以用作功能性食品和膳食补充剂中生物活性物质的来源。