Causes and Control of Culture-Related Flavor Defects in Cultured Dairy Products

Abstract

Research publications on culture-related flavor defects in fermented dairy products are reviewed. Bitterness and fruity off-flavor in Cheddar cheese, caused by the production of bitter peptides and ethyl esters of fatty acids respectively by starter bacteria, are discussed. Lack of diacetyl flavor in Cottage cheese, cultured buttermilk and sour cream is viewed as a major flavor defect in products being marketed today. Cultures may destroy diacetyl by converting it to acetoin and in the case of Cottage cheese, culturing of the dressing with flavor organisms is recommended to enhance flavor. Harsh or green flavors in fermented products caused by excessive acetaldehyde production may be controlled with starter strains high in alcohol dehydrogenase (aldehyde reductase) or by ensuring that high populations of Leuconostoc are present by adding them as concentrates. For yogurt, however, high acetaldehyde-producing cultures are desirable for typical flavor and testing of Lactobacillus bulgaricus strains for use in yogurt cultures for this property is suggested. Strain dominance as it may contribute to culture defects also is discussed.