Physicochemical and functional properties of mangalo bean (Lablab purpureus L.) starch

The rising search for new starch sources stimulated the interest in several non-conventional raw materials lately. In the present study, starch from unripe (green) Lablab purpureus L. bean was isolated and characterized for morphological, pasting, thermal, and physicochemical properties in order to determine its potential end-use. The chemical composition of the mangalo bean starch was 9.37% of moisture, 0.18% of ashes, 0.09% of lipids, 0.007% of phosphorus, and 45.32% of apparent amylose content. X-ray diffraction confirmed the C-type crystallinity pattern of this starch, typical of leguminous plants. Thermogravimetric-differential thermal analysis indicated that the isolated starch withstood high temperatures. The starch displayed high tendency to retrogradation and resistance to gelatinization. The high amylose content and the water absorption capacity suggest the use of this starch in the production of biodegradable films, preparation of syrups with high glycose content, as well as its incorporation into cooked and canned products.