Effect of lotus seed on viscosity and antioxidant activity of soy-based porridge

Abstract

Background and objectives Soy and lotus seeds were added to rice porridge to develop its nutritional value. Three types of porridge were prepared: rice with soy (RS), rice with lotus seed (RL), and rice with soy and lotus seed (RSL). The viscosity, antioxidant properties, and antibacterial effect of the three different types of porridge were compared to those of rice porridge (control). Findings Compared to control (protein: 1.25% and carbohydrate: 90.5%), RS had higher protein (2.55%) and lower carbohydrate (84.3%) content without any change in the calorie content. The addition of soy decreased the viscosity of rice porridge from 3,861 cP in the control to 751 cP in RS. However, the addition of lotus seed increased the viscosity of rice porridge to 2,788 cP in RL. DPPH value was increased from 9.2% in the control to 18.9% in RS, 59.4% in RL, and 64.4% in RSL. Microbiological index value was decreased from 12,363 CFU/g in the control to 440 CFU/g in RS, while RL and RSL were below the limit of detection. Panelists evaluated the similar tendency of beany, grass, and nutty taste between rice and soy porridges (p > 0.05) as well as the thickness of RSL (4.1) also had a similar score to that of control (5.0; p > 0.05). Conclusions Lotus seed could help improve the viscosity properties and antioxidant capacities of soy-based porridge. Particularly, soy and lotus seed synergistically improved DPPH radical scavenging capacity of porridge. Significance and novelty: Minimal research has thus far been carried out on porridge with the addition of lotus seed. To develop a protein- enhanced porridge, around 30% of rice was replaced with soy. The addition of lotus seed increased the viscosity of soy porridge as well as its antioxidant capacity and antibacterial effects.