Effect of steam parboiling and hot soaking treatments on milling yield, physical, physicochemical, bioactive and digestibility properties of buckwheat (Fagopyrum esculentum L.).

Post-harvest hydrothermal processing of grains are targeted at improving milling performances and nutritional properties. In this study, the effects of two hydrothermal processes, namely steam parboiling and soaking in boiling water for different durations on properties of buckwheat (Fagopyrum esculentum L.) grown in the Indian Himalayan regions were assessed. Both treatments significantly improved milling yield. Changes in grain section morphology were evidenced under scanning electron microscope. Milder processing for 5 and 10 min mostly exerted annealing effect, represented by increased intensities of X-ray diffraction peaks. Starch gelatinization occurred upon prolonged processing for 15 and 20 min. This resulted in decreased crystallinity, increased sedimentation volume, paste thinning during rapid viscosity analysis and lower thermal transition in differential scanning calorimetry. Marginal changes in oil uptake suggested limited protein denaturation. Natural antioxidant compounds were variably denatured. Maillard browning was indicated by CIE L* a* b* colour and antioxidant levels. The starchy flour samples showed partial resistance to enzymatic amylolysis post retrogradation. Soaking in boiling water can be considered as a feasible alternative to conventional steam parboiling for better milling yield of buckwheat. Altered physicochemical and nutritional properties of buckwheat suggested that the hydrothermally modified flours can be used in ready to eat therapeutic food products.

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.

Status of polymorphism, physicochemical properties and in vitro digestibility of dual retrogradation-annealing modified rice starches.

In this research, for the first time, dual retrogradation-annealing modification was applied to three rice starches with 22.7%, 9.8% and 0.3% apparent amylose content (AAC). Amylose partially inhibited the effect of gelatinization on amylopectin crystallinity. Polymorphism in retrograded starches was feeble and unstable. Annealing principally caused amylopectin crystal growth by lamellar rearrangement and simultaneous degeneration of weaker lamellae. Reappearance of physical growth rings occurred. Altered crystalline arrangement had direct effect on cooked paste viscosity, gel texture, swelling power, suspension turbidity, and freeze-thaw stability of the samples. A new prominent X-ray diffraction peak (2θ = 29.1) confirmed development of novel polymorphic form other than characteristic A-, B- and V-types. Crystallite melting enthalpy (ΔH) was higher in dual modified starches (9.9 J/g, 12.9 J/g, 19.0 J/g) than native samples (ΔH = 7.4 J/g, 9.1 J/g, 12.1 J/g). Starch-lipid complexes formed the major portion of the crystalline phase within the modified starch matrices. Amylopectin played the major role in crystalline reformation and formed prominent amylopectin-lipid complexes. Simultaneous conversion of slowly digestible starch to resistant starch occurred. Enhanced thermostability, enzyme resistance and functional properties may be suitably targeted for food and non-food applications of the dual modified rice starches.

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 Bragg's 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.