No abstract

Milling and polishing are important operations during the production of white rice. The degree of milling and polishing has a significant effect on the nutritional aspects of white rice, especially on minerals, due to a non-uniform distribution of nutrients in the kernel. Information on the distribution of nutrients in rice will greatly help to understand the effect of milling and aid in designing procedures that improve technological and sensory properties of rice while retaining its essential nutrients as much as possible. In this study, three kernel shapes (short-, medium-and long-grain) of rice were selected for the study of milling characteristics and distribution of zinc (Zn) and phytic acid using abrasive milling and X-ray fluorescent microscope imaging approaches. Milling characteristics differed with kernel shapes and cultivars. Mass loss (y, %) correlated well with milling duration (x, s) and was fitted using a polynomial equation of y = ax 2 +bx+c (R 2 =0.99). Different kernel shapes of rice resulted in different patterns. Breakage in milling increased with longer duration of milling. The relation between breakage (y, %) and milling duration (x, s) fitted the exponential equation y = ae bx. Levels of phytic acid, as well as Zn decreased with prolonged milling. Phytic acid decreased at a higher rate than Zn. The analysis of different milling runs showed that the concentration of phytic acid decreased from the surface region inward, whereas X-ray fluorescent images indicated that the highest concentration of phosphorus was at the interface of embryo and perisperm. Our results help to understand the milling characteristics of different rice cultivars. Understanding these characteristics offers opportunities to optimize milling procedures for maximum phytate removal, at minimum mineral losses and yield loss.

No abstract

No abstract

The influence of fermentation of whole milled rice granules on the physico-chemical characteristics of rice starch and the rheological properties of rice noodles was investigated. The rice granule samples were fermented at 35°C for 27 h. The results indicated that fermentation did not have a significant effect on the starch and amylose content of rice granules. Protein, lipid and ash content decreased whereas free fatty acid increased during fermentation. The rice noodles made from fermented samples had a lower maximum stress, 54 kPa, and higher maximum strain, 10.8%, and had a white, transparent appearance and favourable chewy mouth-feel compared with the control sample.