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Isolation of starches from various tubers such as elephant foot yam (NYS), taro (NTS), ginger (NGS), green banana (NBS) and lotus stem (NLS) was carried out for studying various characteristics viz. physicochemical, differential scanning calorimeter (DSC), rapid visco analyzer (RVA), rheological, morphological and colour in order to explore their end use potential. A significant variation was observed in pasting properties of isolated starches. X‐ray diffractometery (XRD) showed a B‐type crystal pattern of banana starch, while yam, taro, ginger and lotus starches had A‐type crystal pattern. Scanning electron microscope (SEM) revealed that taro starch possessed the smallest granule size having cluster pattern while lotus starches have the largest granular size with hemispherical facets having dents or hollows at one end. Thermal properties of isolated starches revealed that NLS had lowest To, Tp, Tc values i.e. 68.3, 72.0 and 76.8°C, respectively. Similarly the lowest gel characteristics such as hardness, gumminess, chewiness and adhesiveness 3.09 g, 1.45, 1.27, 8.42 gs, respectively, were also found in NLS. L* values of NTS and NYS starches were the highest i.e. 93.36, 93.29 with no significant difference whereas the lowest i.e. 89.917 in NGS.

Lotus rhizome starch was isolated and subjected to chemical modification using different levels of oxidation, cross-linking, and dual modifications. Fourier transform infrared (FTIR) and X-ray diffraction analyses confirmed the successful modification of native starch. The carbonyl, carboxyl contents, and degree of cross-linking of modified starch were in the range of 0.03-0.07%, 0.07-0.15%, and 4.31-58.28%, respectively, for oxidized, crosslinked, and dual-modified starches. Amylose content varied from 13.57% to 20.60% for native and modified starches. Swelling power (SP) and solubility were temperature dependent and increased with increase in temperature. Oxidation and dual modification increased solubility, while cross-linking decreased solubility. Paste clarity, degree of crystallinity, and whiteness of starches increased significantly with increase in level of modifications. Peak, breakdown, and setback viscosities of the modified starches decreased with increase in modification. Phase transitions using DSC presented lower enthalpy values for modified starches. Gelatinization temperature increased due to modification whereas scanning electron micrographs revealed that modification altered the starch morphology.

Elephant foot yam starch based composite containing glycerol, whey protein concentrate and psyllium husk were used to develop biodegradable films by casting technique. Adding glycerol, whey protein concentrate and psyllium husk to low amylose elephant foot yam starch overwhelmed the flaws for physicochemical, barrier, optical, mechanical, thermal, and surface properties required for the development of biodegradable films. Prepared composite biodegradable film presented higher tensile strength, lower water vapor permeability, and solubility as compared to elephant foot yam starch film alone. Surface and cross‐sectional morphology depicted uniformity, and structural integrity in composite polymeric matrix as compared to rough surface with cracks in elephant foot yam starch films. The SEM micrographs analysis indicated strong interactions of elephant foot yam starch with glycerol resulting in a dense network whereas differential scanning calorimeter indicated film thermal stability. X‐ray diffractogram revealed amorphous character whereas broad amorphous peak demonstrates molecular miscibility and interaction between the composites. Fourier transform infrared spectroscopy indicated strong interactions along with higher degree of cross‐linking in composites which confirms the film forming characteristics of composite ingredients. Hence, composite film properties reveal their potential as food packaging material, thus enabling the replacement of synthetic packaging materials in various food applications. POLYM. COMPOS., 39:E407–E415, 2018. © 2017 Society of Plastics Engineers