Extract isolated from cranberry pomace as functional ingredient in yoghurt production: Technological properties and digestibility studies

Yoghurt is recognized as an excellent delivery vehicle for plant-derived phenolic compounds. This study aimed to examine the effect of polyphenol-rich extract produced from cranberry pomace (CE) on the fermentation, textural characteristics, and digestibility of yoghurt. The addition of 0.25%–0.75% of CE to milk prior to fermentation caused an increase of protein particle size and accelerated the acid-induced gelation time of milk depending on the CE concentration due to the complexation of the polyphenols with the milk proteins. Protein–polyphenol interactions were responsible for forming aggregated protein networks from larger particles with higher viscosity and lower syneresis in yoghurt produced with CE compared to that made without CE. However, the addition of the extract did not affect the viability of the yoghurt bacteria. In gastrointestinal digestion, yoghurt with CE showed slower digestion of proteins than the control and a limited release of phenols at the end of intestinal digestion. The overall findings suggest that addition of CE into yoghurt is a promising method of making yoghurts with good textural properties and high yoghurt bacteria viability. Digestibility studies of the product need to be extended to explain the influence of undigested proteins and non-released phenolic compounds on the colonic microbiota.