Autolysis of yeast cells occurs after they have completed their life cycle and entered the death phase. It is characterized by a loss of cell membrane permeability, alteration of cell wall porosity, hydrolysis of cellular macromolecules by endogenous enzymes, and subsequent leakage of the breakdown products into the extracellular environment. Although a naturally occurring event, autolysis can be induced by exposing yeasts to elevated temperatures (40–60 °C), organic solvents, or detergents. Yeast autolysis occurs in many foods and beverages, where it may affect their sensory quality and commercial acceptability.
Induced autolysis is widely exploited for industrial application. Yeast autolysates (yeast extract) are used in the food industry as flavor enhancers and added in the production of meat paste, meat pie filling, soups, sauces, and snacks.
Autolysis of yeasts during maturation and aging of beer, wine, and sparkling wines causes the release of amino acids, proteins, nucleic acid degradation products, free fatty acids, and polysaccharides that affect the sensory properties of these products and could serve as nutrients for the growth of bacteria. In this article, we will focus on the yeast autolysis of wine, which has received much attention in recent years.