Mechanism of Different Cooking Methods Affecting Sensory Quality of Pruple Sweet Potato

Three representative purple fleshed sweet potato varieties, Taizishu NO.1, Violet and Vietnamese purple sweet potato were selected as materials. Sensory evaluation, moisture content, starch content, sugar content were explored after baking, steaming and microwave with Pushu NO.32 as the control. Combining with correlation analysis and partial least squares regression (PLSR), the correlations of consumer sensory evaluation and physicochemical property were explored. The sensory evaluation results showed that, Taizishu No.1 obtained the highest score. The sweetness and texture were the driving attributes which could determine consumer preference. The cooking method significantly affected the sensory quality of purple sweet potato. Moisture and starch content of purple sweet potato were decreased after cooking while content of reducing sugar and total sugar were increased. Moreover, sucrose and maltose content increased, while glucose and fructose showed different changes with different varieties and cooking methods. Steaming facilitated water retention and roasting was good for high temperature saccharification during ripening. The correlation analysis showed that the sensory evaluation score was significantly positively correlated with water content and reducing sugar (fructose and glucose) (P<0.01), and negatively correlated with starch content (P<0.05). The effect of water, glucose, fructose, starch and reducing sugar on sensory evaluation score increased gradually. PLSR indicated that main indicators affecting sensory quality of purple sweet potato were reducing sugar, fructose and glucose. This study could provide a scientific basis for establishing sensory prediction model of purple sweet potato, develop the best processing technology of different varieties of purple sweet potato, and guide the breeding of fresh purple sweet potato.