The effect of commonly used dairy processing techniques and unit operations on the equol content of dairy products

Since a large portion of the milk consumed by human is processed, the aim of this study was to determine possible changes in equol content upon processing milk. Individual milks with different levels of equol content were collected from the morning milking to make skimmed milk and cream, as well as pasteurised and sterilised full fat milks. Pasteurised milk was further processed into yoghurt, kefir, cottage cheese and whey. Yoghurt and kefir were also produced from sterilised milk. Equol content was not affected by either pasteurisation or sterilisation. Compared with raw milk, a higher concentration of equol was measured in skimmed milk, but equol content in cream was lower. The concentration of equol remained unchanged after yoghurt production but was reduced by more than 50% after kefir production. The equol content in whey was low compared with that of raw milk, while it increased sharply in cottage cheese.