CHANGES IN NUTRITIONAL COMPOSITION AND ANTI-NUTRITIONAL FACTORS OF SISNU IN HOT WATER AND STEAM BLANCHING AND COOKING METHOD

Abstract

Sisnu is an important traditional food item along with a high nutrient value. Sisnu is grown wild, due to which it has been consumed as an inexpensive source of nutrient in Developing countries, like Nepal. There is enough data to support the high nutrient quality of sisnu. However, their anti-nutritive values have not been explored, which are either potentially toxic or may limit the availability of nutrient. Different processing techniques are often utilized in order to reduce anti-nutritional factors. However, cooking is a common and easy form of processing in plants that are consumed as a food source. Sisnu (U. plaviflora), was brought from Bishnupaduka, Dharan-20, Sunsari district, Nepal and the changes in nutritional composition and anti-nutritional factors of sisnu in different household steam and hot water-based cooking practices was studied on the basis of loss of anti-nutrients and retention of vitamin C at different time of cooking. The mean value of phytate, oxalate and vitamin C contents in the raw Sisnu were found to be 2.99, 1471.32 and 33.14 mg/100g (DM) respectively. Both steaming and boiling showed significant reduction (p<0.05) in Phytate, oxalate and vitamin C. There was significant reduction in oxalate content on both steaming for 5 and 15 min (1162.713 and 1051.514 mg/100g DM) respectively on dry basis. But boiling for 5 and 15 min showed higher reduction of oxalate (763.49 and 704.94 mg/100g respectively on dry basis). Boiling for 15 min showed reduction of phytates (2.18 mg/100g), oxalates (704.94 mg/100g DM) and vitamin C (11.4 mg/100g DM). Loss of vitamin C in boiling was higher than in steaming. Retention of vitamin C was found to be higher in steaming for 5 min (28.88 mg/100g DM) and 15 min (225.01 mg/100g DM) respectively on dry basis. Reduction of antinutrient was observed high on boiling for 15 min but retention of vitamin C was very low. Hence, steaming was considered as an effective method of cooking.