Effects of different pretreatments on the physicochemical characteristics and quality criteria of chestnut (Castanea sativa Mill.) pickle: A new value-added product

Abstract

Effects of roasting (80 degrees C, 3 and 5 min) and boiling (chestnut to water 1:2 (w/w), 7 and 9 min) pre-treatments and brine ratios (5% and 7%) on physicochemical and bioactive properties of firstly developed chestnut pickles were investigated. Dry matter and total acidity increased by pickling while pH and salt were decreased. Total, reducing sugars and starch of pickles ranged between 2.13-3.53, 0.28-0.45, and 18.61-23.67 g/100 g respectively. L*, b*, C*, and h degrees decreased in comparison to chesnut as a* displayed an increment. The highest phenolics were determined from the pickle produced in 7% brine without any treatments (126.11 mg GAE/100 g dm) while the pickle produced in 7% brine by 5 min roasting had the highest antioxidant capacity (CUPRAC: 14.83, FRAP: 21.38 mu mol TE/g dm). Usage of chestnut as a raw material allowed designing of a sensorially accepted pickle additionally, roasting and salt ratio were concluded as the key factors.Practical applications High-quality chestnuts can be used in various forms such as frozen, sterilized, or dried in gastronomy. On an industrial scale, chestnut is processed into canned products, candies, creams, flour or it can be used as ingredients for biotechnological purposes due to its high starch content. Processing low or good quality chestnuts into alternative end products is an economically profitable way as well as reducing the waste levels from industrial processing while increasing the added value of chestnut products. Thus, by pickle production, chestnut was processed into a nonseasonal shelf life prolonged product for markets for the first time.