TEXTURE PROFILE ANALYSIS (TPA) OF ORGANIC SWEETPOTATO (IPOMOEA BATATAS) CULTIVARS AS AFFECTED BY DIFFERENT PROCESSING METHODS

摘要

Almost one-third of the entire U.S. is buying organic produce. It is believed that organic foods taste better and are more nutritious than conventional foods. To develop successful market positioning, the characteristics desirable to consumers, for sweetpotato must be identified. Different processing methods particularly thermal treatments would impact sweetpotato textures differently and as such affect the consumer liking and eventually product acceptability. Clear understanding of the influence of different thermal treatments on the textural characteristics of sweetpotato is therefore needed. The major objective of this research work was to evaluate the impact of different thermal processing techniques such as baking, pressure cooking, and open cooking on the textural characteristics of sweetpotato cultivars. Six cultivars of sweetpotato grown on a certified organic farm were subjected into different thermal treatments. Baking was done using an air oven for 60 min. Pressure cooking was done using a pressure cooking for 15 min and open cooking was done using a vessel filled with water (500 ml) for 1 hour. In all thermal treatments, the inside product temperature was kept constant (60±2°C). The texture parameters were recorded with a texture analyzer using a 100 mm dia probe. The samples were also penetrated 5 mm from the surface using a needle probe of 2 mm dia. Maximum peak force was set in Newtons. Across the treatments, open cooked Japanese Purple was found to be the hardest although not significantly different from Hernandez open cooked cultivar. Baked Old Yellow sweetpotato was the most gummy and chewy while the softest cultivar was the pressure cooked Old Yellow; however it did not differ significantly from the other five cultivars tested.