Microbiological and physico-chemical changes in lotus seeds as influenced by ultraviolet radiation

Abstract

Lotus seeds are sensitively perishable and browning. However, few publications have emphasised on the application of UV-C treatment. The purpose of this work was to assess the potential effect of UV-C irradiation on the physico-chemical and microbiological quality of lotus seeds during storage at 4℃ for 8 days. The UV-C exposure times of 5 mins and 10 mins were evaluated. The results showed that the total viable count of 10 mins-UV-C treated lotus seeds met the standard quality of Thai Industrial Standards Institute (TISI) crispy lotus seeds (TCPS 490-2547) (≤ 3 log CFU/g) although the yeast and mould of all treatments were not affected by UV-C radiation (> 1 log CFU/g). Moreover, the reduction level of browning degree was not affected by UV-C, whereas the accumulation of phenolic content and the delay of product softening were found in the UV -C treated sample for 10 mins when compared with the control treatment. Consequently, the UV-C treated for 10 mins could be used as a promising approach to control the growth of total bacterial count in lotus seed product during storage at 4℃.