A relationship between chemical constituents and physicochemical and textural properties of different Korean sweet potato (SP) cultivars were investigated in terms of the hardness of raw and cooked root, alcohol insoluble solid (AIS), starch and amylose content, amylase activities, and pasting properties. Correlation coefficients were analyzed and principal component analysis was performed. The hardness of cooked root was found to correlate with the hardness ratio of cooked/raw SP, AIS content (0.75**), starch content (0.64**), and peak viscosity of SP powder (0.56*). It was discovered that SP cultivars could be classified into mealy (Sincheonmi, Daeyumi, Sinyulmi), intermediate (Dahomi, Sinjami, Geonhwangmi, Yeonjami, Pungwonmi), and waxy (Juhwangmi, Sinhwangmi) types depending on the first principal component (PC1, 68%). Therefore, it was found that the texture types of SP cultivars could be predicted from hardness of cooked root and are in relation to AIS and starch contents, and peak viscosity of raw powder.

Purpose: To increase the availability of Korean sweet potato (SP), the quality characteristics of the sweet potato pastes (SPPs) and rice madeira cake (RMC) using them were investigated. Methods: Ten different SPPs, orange fleshed Sinwhangmi, Juwhangmi, purple fleshed Sinjami and Yeonjami, Cream fleshed Sinyulmi, Sinchunmi, and newly developed Geonwhangmi, Dahomi, Daeyumi, and Pongwonmi were used. Their pastes were prepared by washed, peeled, steamed, crushed, vacuum packed and stored in a freezer until use. Results: The SPPs and RMC with them were significant difference from different cultivars with color value, rheology and texture properties, and preference test. The SPP showed the highest lightness value in Sinchunmi (55.89) and the highest viscosity in Geonhwangmi (55.33 poise). The RMCs with SPPs had lower values in hardness and chewiness than the RMC without SPP. Overall quality of preference test showed the highest values in RMC with Sinyulmi and Sincheonmi. Conclusion: The best quality of sweet potato shaped rice madeira cake was made using Sinyulmi and Sinchunmi pastes. It is suggested that sweet potato paste is possible to use as the biomaterials for application of processed foods.

Purpose: The properties of starch and starch gel prepared from a newly inbred sweet potato, Daeyumi were compared to the properties of starch and starch gel prepared from Sinyulmi which is a well known mealy type sweet potato. Methods: The starch was isolated by using the alkaline steeping method. Physicochemical, pasting, and thermal properties, and crystallinity were measured. The texture properties of starch gel (10%, w/w) were examined. Results: The amylose contents of Daeyumi and Sinyulmi starches were 25.57% and 22.59%, respectively. The initial pasting temperature of Daeyumi starch was significantly higher than that of Sinyulmi starch (p<0.05), but other paste viscosities were not different. The peak and conclusion temperatures of Daeyumi starch were higher than those of Sinyulmi starch by differential scanning calorimetry. The shape of Daeyumi starch gel was more clear and rigid than the shape of Sinyulmi starch gel. The surface and the upper side of Daeyumi starch gel were smoother than the surface and the upper side of Sinyulmi starch gel. Hardness and gumminess were higher in Daeyumi starch gel than in Sinyulmi starch gel. The crystallinity types of Daeyumi and Sinyulmi starches were Cb and A types, respectively, but starch gels showed an amorphous type. Conclusion: Therefore, it is suggested that Daeyumi starch would have better physicochemical properties and higher quality of starch gel than Sinyulmi starch.