Biotransformation of Coconut (Cocos nucifera L.) Endosperm into a Fermented Beverage: Impact on Physicochemical Attributes, Organoleptic Quality and Antioxidant Capacity
Saji Gomez *
Department of Postharvest Management, College of Agriculture, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala, 680656, India.
Anagha Lakshmi Ganesh
Department of Postharvest Management, College of Agriculture, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala, 680656, India.
P. Anshida
Department of Postharvest Management, College of Agriculture, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala, 680656, India.
K. Rixon Raphael
Department of Postharvest Management, College of Agriculture, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala, 680656, India.
R. S. Maheswari
Department of Postharvest Management, College of Agriculture, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala, 680656, India.
*Author to whom correspondence should be addressed.
Abstract
Coconut liquid endosperm discarded during coconut oil processing offers a potential substrate for value-added fermentation. This study examined the physicochemical characteristics, sensory acceptability and antioxidant activity of a fermented beverage produced from mature coconut (Cocos nucifera L.) liquid endosperm. Coconut water obtained from approximately 12-month-old West Coast Tall nuts was adjusted from 7.0 to 24 °Brix using cane sugar and inoculated with 1.0% Saccharomyces cerevisiae. Following fermentation, racking, clarification and filtration, the beverage was aged in stainless-steel tanks at 15 °C for 12 months. Physicochemical properties were monitored during storage, and sensory quality was evaluated by a semi-trained panel of 30 participants. Total soluble solids declined from 7.2 to 6.4 °Brix between two and 12 months of storage, while titratable acidity increased slightly from 0.38% to 0.40%. Alcohol content decreased from 13.07% to 12.24%, and total phenolics declined from approximately 26 to 21 mg per 100 mL. Vitamin C and total sugars also decreased during storage. The aged beverage achieved an overall sensory acceptability score of 8.0 out of 9.0, with aroma receiving 9.0. Its DPPH IC₅₀ value (1.280 µg mL⁻¹) was lower than that of fresh coconut endosperm (1.408 µg mL⁻¹), indicating higher radical-scavenging activity under the assay conditions. These findings support further consideration of mature coconut liquid endosperm as a substrate for fermented beverage production.
Keywords: Coconut liquid endosperm, Cocos nucifera, Saccharomyces cerevisiae, alcoholic fermentation, coconut wine, physicochemical properties, beverage ageing, organoleptic quality, phenolic compounds, antioxidant capacity