Chemical and functional properties of Phaseolus lunatus and Manihot esculenta starch blends

摘要

Chemical and functional characteristics were determined for Phaseolus lunatus (P) and Manihot esculenta (M) starches, and blends of these two starches (25P/75M, 50P/50M, 75P/25M (%, w/w)). Starch purity varied from 95 to 98%. The lowest amylose content was in M. esculenta (17.3%) and the highest in P lunatus (32.4%) with the blends having intermediate values. Total dietary fiber content in M. esculenta was 1.7%, and 1.2% in P. lunatus; of the blends the 25P/75M had the highest percentage (2.3%). Initial gelatinization temperature was higher for P. lunatus (67.9 degrees C) than for M. esculenta (57.6 degrees C), with the blends having intermediate values. P lunatus starch had the highest retrogradation value (8.3 mL/50 g starch) of all the starches, while M. esculenta and the 25P/75M blend had no retrogradation at all. The P. lunatus paste had the highest viscosity (125.5 mPa s) compared to the other pastes, which were statistically similar (P>0.05). Gel clarity was lower in P lunatus (23.84%T) than in M. esculenta (51.76% ), with intermediate values in the blends. The 25P/75M blend was selected as having the best combination of characteristics, since it showed not retrogradation, had high viscosity (102 mPa s), and was stable in the heating-cooling cycle. This makes it a starch with suitable functional properties for use in a variety of foods. These results suggest that blending native starches from different vegetable sources improves their properties.