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Summary The viscous and thermal behaviour of five types of micronutrient-fortified reconstituted rice premixes extruded at pre-optimised extrusion conditions (36% moisture content, 150 rpm screw speed and 89 °C barrel temperature) have been investigated using rapid visco analyser (RVA) and differential scanning calorimetry (DSC). The highest peak viscosity (1279 cP), lowest gelatinised starch percentage (16.32) and highest enthalpy of gelatinisation (8.2 J g−1) were recorded in rice premix fortified with retinyl palmitate and micronised ferric pyrophosphate. The scanning electron microscopic analysis (SEM) also revealed that reconstituted rice premix fortified with iron (micronised ferric pyrophosphate) and retinyl palmitate was in closer resemblance to that of natural rice than any other reconstituted rice premix. The work demonstrated that vitamin A- and iron-fortified reconstituted rice with meso/micro structure and pasting behaviour close to that of natural rice can be produced using retinyl palmitate and micronised ferric pyrophosphate as vitamin A and iron source, respectively.

The aim of the present study was to design, fabricate, and evaluate a walnut bleaching machine. The machine consists of a feed hopper, rotating drum, motor, reduction gear, belt and pulley system, pump, storage tank, lever, delivery chute, and a control box. The bleaching process is achieved by simultaneous chemical and mechanical action. In order to assess the performance of the machine, acidified sodium chlorite, sodium hypochlorite, and hydrogen peroxide were used as bleaching agents in 2 and 3% concentrations for 5 and 7 min of time. The result of the performance tests showed the significant effects of bleaching agent and bleaching time on all the performance and color parameters with the exception of damaged walnut percentage. Treating inshelled walnuts with 3% sodium hypochlorite +0.2% HCl (T5) for 7 min followed by rinsing in plain water resulted in attractive and bright shell appearance of walnuts. Further, highest bleaching efficiency (94.69%), fully bleached walnut percentages (94.19), and lowest partially bleached walnut percentage (5.47) were recorded when T5 was used as bleaching agent for 7 min in bleacher. Practical applications Dark shell colored and stained walnuts have poor consumer acceptability. In India, crude methods are employed to remove these shell stains, which compromise the shell integrity, thus leading to moisture ingress into kernels. This results in kernel darkening, mold growth, and oxidative rancidity in walnuts. However, for improving the surface appearance, the walnuts after dehulling are required to be processed. Therefore, a walnut bleaching machine was developed and various chemical bleaching agents were investigated to study their effects on surface cleaning of inshelled walnuts. A technology of this nature can be useful to walnut growers and processors.