Himjyoti Dutta

Effect of acid concentration and treatment time on acid-alcohol modified jackfruit seed starch properties.

The properties of starch extracted from jackfruit (Artocarpus heterophyllus Lam.) seeds, collected from west Assam after acid-alcohol modification by short term treatment (ST) for 15-30min with concentrated hydrochloric acid and long term treatment (LT) for 1-15days with 1M hydrochloric acid, were investigated. Granule density, freeze thaw stability, solubility and light transmittance of the treated starches increased. A maximum decrease in the degree of polymerisation occurred in ST of 30min (2607.6). Jackfruit starch had 27.1±0.04% amylose content (db), which in ST initially decreased and then increased with the severity of treatment; in LT the effect was irregular. The pasting profile and granule morphology of the treated samples were severely modified. Native starch had the A-type crystalline pattern and crystalline structure increased on treatment. FTIR spectra revealed slight changes in bond stretching and bending. Colour measurement indicated that whiteness increased on treatment. Acid modified jackfruit seed starch can have applications in the food industry.

Traditional Parboiled Rice-Based Products Revisited: Current Status and Future Research Challenges

Abstract Parboiling is an age old technique carried out to improve rice quality. Different grain parboiling techniques have been traditionally followed and scientifically developed for preparation and industrialization of rice. The state of Assam, India produces a large number of rice varieties, some of which are traditionally processed into peculiar parboiled rice products like Hurum, Komal chaul, Bhoja chaul and Sandahguri, which are of both ethnic and possible commercial importances. In spite of extensive research carried out on parboiled rice, these products and their special parboiling techniques have not been sufficiently explored. The status of research on parboiled rice as a whole with special attention to these lesser known speciality products of Assam is extensively reviewed. Future scope of research on these products is also identified.

Physical, physicochemical and nutritional characteristics of Bhoja chaul, a traditional ready-to-eat dry heat parboiled rice product processed by an improvised soaking technique.

Bhoja chaul is a traditional whole rice product processed by the dry heat parboiling technique of low amylose/waxy paddy that is eaten after soaking in water and requires no cooking. The essential steps in Bhoja chaul making are soaking paddy in water, roasting with sand, drying and milling. In this study, the product was prepared from a low amylose variety and a waxy rice variety by an improvised laboratory scale technique. Bhoja chaul prepared in the laboratory by this technique was studied for physical, physicochemical, and textural properties. Improvised method shortened the processing time and gave a product with good textural characteristics. Shape of the rice kernels became bolder on processing. RVA studies and DSC endotherms suggested molecular damage and amylose-lipid complex formation by the linear B-chains of amylopectin, respectively. X-ray diffractography indicated formation of partial B-type pattern. Shifting of the crystalline region of the XRD curve towards lower values of Braggs angle was attributed to the overall increase in inter-planar spacing of the crystalline lamellae. Resistant starch was negligible. Bhoja chaul may be useful for children and people with poor state of digestibility.

Properties of annealed jackfruit (Artocarpus heterophyllus Lam.) seed starch

Jackfruit seed starch was annealed by single stage and double stage processes and characterised for changes in properties. Single-stage annealing gave higher crystalline order than double-stage annealed starch. No major change in the granular morphology was observed. Annealing resulted in notably altered pasting properties. Increased peak viscosity was indicative of molecular rigidity developed in the granules due to annealing. The increased thermal stability in DSC and specific peak sharpening in the XRD patterns of single-stage annealed starches indicated development of ‘site specific’ crystallinity. The new crystallites formed during the first stage of double-stage annealing were heat labile as crystallinity lowered after the second stage. Single stage annealed jackfruit seed starch can be used for noodle making.