Effects of concentration by block freezing and vacuum evaporation on the physicochemical properties and digestibility of whey

Abstract

Whey is a source of protein of high nutritional value. In this work, the effects of block cryoconcentration assisted by centrifugation and vacuum evaporation on the physicochemical properties and in vitro digestibility of whey were determined. In vitro digestibility analysis was performed by evaluating the degrees of protein hydrolysis of the fresh, evaporated and cryoconcentrated whey protein samples from the third cycle. The results showed that the samples after the second and third cryoconcentration cycles had no significant differences in protein or lactose content. The in vitro digestibility analysis indicated that the protein obtained by cryoconcentration showed better gastrointestinal digestibility than that obtained by evaporation, with values of 68.2% and 55.4%, respectively. This study demonstrates that block cryoconcentration assisted by centrifugation is an efficient and novel technique that enables the preparation of concentrated protein solutions of high nutritional and biological value.