Improving chestnut physicochemical properties through fermentation – Development of chestnut Amazake

The increased awareness of population regarding the impact of consumption habits is leading to interest in new, innovative, diversified and health promoting foods. In this work, two new amazake fermented products were developed with chestnut (Castanea sativa Mill.), using rice or chestnut koji as source of glycolytic enzymes. The analysis of the amazakes evolution showed improvements in chestnuts physicochemical characteristics. The fermented products presented higher values of soluble protein, sugars, starches, antioxidant capacity, and similar values of ascorbic acid for chestnut koji amazake. The adhesiveness increased, which is related to the enhanced concentrations of sugars and starches. The evolution into less structured products was observed in the firmness followed by a consistent decrease of the viscoelastic moduli. The developed chestnut amazakes can represent a suitable alternative to traditional amazake, creating an opportunity for valorisation of chestnut industrial by-products, as new, tasty, and nutritive fermented products with potential functional characteristics.