Isolation, partial characterization and in vitro digestion of starch from Ariopsis peltata and Lagenandra toxicaria tuber

The starch from two aroid tuber viz. Ariopsis peltata and Lagenandra toxicaria were isolated and evaluated for their morphological, physical and chemical properties. The tubers of these plants are used as food and medicine by the indigenous communities. The starch yield from A. peltata tuber was 25 ± 1.7% with an amylose content of 10 ± 0.9%, while the tuber of L. toxicaria contained 28 ± 6.5% starch with 15 ± 0.5% of apparent amylose in it. The starch isolated from both the tubers was highly pure (99%) starch exhibiting an A-type X-ray diffraction pattern. The starch granules of L. toxicaria were of various shapes and exhibited a smooth surface without any cleft or break. While the starch granules of A. peltata were spherical with smooth surface, as well as rough surface. The breaks and clefts were apparent on the rough-surfaced granules. The gelatinization temperature range for A. peltata and L. toxicaria starch is approximately 23 °C and 19 °C respectively. A. peltata starch showed higher thermal stability compared to L. toxicaria starch and either of the starch was rapidly digestible as evident from in vitro digestion study. The physicochemical properties of both the starches render them stable to withstand extreme processing. Besides they also mimic simple sugar in digestibility. So it can be utilized as a substitute for simple sugars in brewing and pharmaceutical industries.