Influence of storage temperature on invertase activity and sugar content in potato (Solanum tuberosum L.) tubers

Invertase activity and reducing sugar content were estimated in tubers of potato cultivars Kufri Lauvkar, Kufri Jyoti, Atlantic and Frito Lay 1625 at the time of storage and during storage at 6°C and 20°C for 90 days, Freshly harvested tubers of all the cultivars contained low levels of reducing sugars as well as basal and total invertase activities. Both basal and total invertase activities increased rapidly during storage at 6°C but increase was much steeper in case of basal activity. Atlantic and Frito Lay 1625 showed negligible accumualation of reducing sugars and invertase activities compared to Indian cultivars Kufri lauvkar and Kufri Joyti during storage at 6°C for 90 days. There was a general trend of decline in reducing sugar content and invertase activity at higher temperature (20°C) of storage. Present results indicated that invertase activity caused reducing sugar formation during low temperature storage of potato tubers resulting in sweetening of tubers ~nd deterioration of processing quality.