Development and quality evaluation of Blue Butterfly Pea flower (Clitoria ternatea L.) based instant rice.

Abstract

Blue butterfly pea flower (Clitoria ternatea L.) is gaining attention, especially in the food industry, for its potential uses. Rice is Sri Lankans’ staple food and the modern lifestyles have created a growing market demand for instant rice. This study aimed to develop C. ternatea flower-based instant rice using the rice variety BG 358. Initially, instant rice was prepared using five treatments. T1) Boiling rice ( 9 minutes), simmering, freezing ( -20 °C; 24 hours), thawing, drying (70 °C; 2 hours), T2) Boiling rice (9 minutes), simmering, 2 minutes rinsing in cold water, freezing (-20 °C; 2 hours), thawing, drying (70 °C; 2 hours), T3) Preheating rice (93°C; 3 minutes), 11 minutes cooking (92°C), steaming, 2 minutes washing (cold water), freezing (-20 °C; 2 hours), thawing, drying (100 °C; 2 hours), T4) Cooking in a rice cooker (18 minutes), simmering, rinsing (cold water), freezing (-20 °C; 2 hours), thawing, drying (70 °C; 2 hours, T5) Cooking in a rice cooker (18 minutes), simmering, freezing (-20 °C; 24 hours), thawing, drying (70 °C; 2 hours). The best treatment was selected after a sensory evaluation by thirty untrained panelists. Moisture content of the product was recorded. Dehydrated C. ternatea were incorporated to the rice (1- 3% wt/wt) during cooking and the optimum amount determined by a sensory evaluation. Physicochemical properties, water holding capacity, volume expansion, anthocyanin content and antioxidant activity (DPPH radical scavenging activity) were evaluated after reconstitution (treated). Rice, cooked in a rice cooker for 30 minutes without incorporating C. ternatea was the control. Microbial quality of the product (50g; packed in LDPE, refrigerated) was evaluated for three months. Final moisture content of the best treatment (T2) was 9%. The optimum flower content (2% wt/wt) incorporated instant rice was reconstituted within 8 minutes by adding boiling water (100 °C) and its anthocyanin content (36.28 mg/100g of rice) and antioxidant activity (73.91% inhibition) were significantly higher (p<0.05) compared to the control (anthocyanin not detected and 43.47% inhibition respectively) while physicochemical properties, water holding capacity and volume expansion were insignificant (p>0.05). Microbial quality remained below 102 cfu/g throughout testing. This study suggests using C. ternatea flower to prepare instant rice.