Head rice

Milled rice is comprised of head rice, second heads and brewers rice. Unlike most grains, the primary use of rice is its direct consumption as a table food. The two other major uses are in processed foods and to make beer. Head rice is the only rice that is used for table consumption and represents —82% of the milled rice. Broken rice, which is comprised of second heads and brewers rice, is considered to be a byproduct of milling and represents —18% of the milled rice. Broken rice generally has a lower market value than head rice. Due to the relatively high cost of head rice compared with other grains, lower cost by-products of head rice production are preferred for use in processed foods and beer production. In 2004-2005, the USDA estimated that the principle outlets for milled rice in the US included 52% for direct food use,... 

Quality of tempering reduced the percentage of fissured kernels to 3.35% and enhanced head rice yield (HRY) independently with two drying steps to 96%... 

High moisture content is the main problem of paddy, especially those harvested during rainy season. High temperature developed inside moist paddy pile can deteriorate paddy quality (in such terms as color, head rice yield, smell) within only 2 or 3 days. Harvested paddy with high moisture content needs to be dried immediately to preserve its quality. 

FIGURE 28.10 Effects of fluidized-bed drying temperature and amylose content on head rice yield, (a) Amylose content of 25%-27% (b) amylose content of 15%-18%. (From Tirawanichakul, S. et al., Drying TechnoL, 22, 1731, 2004.)... 

Figure 28.14 shows the relationship between the head rice yield and the final moisture content of paddy that undergone superheated steam fluidized-bed drying at 150°C-170°C. The head rice yield slightly changed when the paddy was dried from 41%-42.5% to 20% (d.b.) the head rice yield... 

FIGURE 28.14 Relationship between head rice yield and final moisture content during drying by superheated steam. Initial moisture content = 41.5%-42.5% (d.b.). (From Taechapairoj, C. et ah, Drying TechnoL, 22, 719, 2004.)... 

Impact of Drying Conditions on Head Rice Yield for Paddy and Parboiled Rice... 

Abud-Archila, M., Courtois, F Bonazzi, C Bimbenet, J. J., 2000. Processing quality of rough rice during drying - Modelling of head rice yield versus moisture gradients and kernel temperature. J. Food Eng. 

Elbert, G., Tolaba, M. P., Suarez, C., 2001. Effects of drying conditions on head rice yield and browning index of parboiled rice. J. Food Eng. 47 37-41. 

Iguaz, A., Rodriguez, M., Virseda, P., 2006. Influence of handling and processing of rough rice on fissures and head rice yields. J. Food Eng. 77 803-809. 

Jindal, V. K., Siebenmorgen, T. J., 1994. Effects of rice kernel thickness on head rice yield reduction due to moisture adsorption. Trans. ASAE 37(2) 487 90. 

Siebenmorgen, T. (., 1994. Role of moisture content in affecting head rice yield, in Rice scierKeandtedirwlogy edsW E. Marshall. J. 1. Wadsworth). Marcel Dekker, New York, USA, pp. 341-380. 

Siebenmorgen, T. (., Counce, P. A., Lu, R., Kocher, M. E., 1992. Correlation of head rice yield with individual kernel moisture content distribution at harvest. Trans. ASAE 35(6) 1879-1884. 

Throughout the entire milling process, a number of kernels are unavoidably broken. So, a series of machines classify the different size kernels as head rice (whole and 3/4 kernels). 

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