Moisture Absorption Behaviour, Extract Yields and Sensory Evaluation of Soaked Cyperus esculentus

Abstract

This work investigated the comparison in the moisture absorption behavior, the extract yields and sensory evaluation of brown and yellow varieties of tiger nut (Cyperus esculentus) tubers when soaked in water for tiger nut beverage production. For each tuber variety, 3 g of it was steeped in 30 ml of distilled water for 5 days and periodically re-weighed at 24-hour intervals until the tubers had attained saturated moisture content. Furthermore, 200 g of each variety was steeped in 800 ml of sterile distilled water for periods of 0 hour (control), 24 hours, 48 hours and 96 hours, respectively. At the end of each time interval, the tubers were removed, ground in 800 ml sterile distilled water, sieved, and the beverage liquid filtrate obtained measured as the percentage extract yield for the tuber sample. Aroma, colour, taste and acceptance were the parameters used for sensory evaluation. The brown tubers showed a significantly (P≤0.05) higher moisture absorption behavior than the yellow tubers; the brown and yellow had the highest rate of moisture absorption ability of 52.22% and 35.56%, respectively, occurring after soaking for 24 hours. At same 24 hours of the soaking period, the resultant extracts obtained from the brown and yellow tubers were at a significant peak yields of 92% and 89.5%, respectively. Extracts from the brown tubers were preferred in taste and colour to those from the yellow variety. Water absorption potentials of tiger nut tubers during soaking process, has potential effects on the beverage extraction and quality.