Biochemically assisted rice whitening for improving head rice yield

Abstract

The maximum attainable head rice yield in conventional long grain rice milling is approximately 64%, with around 15% being lost as a result of broken rice kernels. The primary objective of this project was, therefore, to improve the milling yield. To achieve this goal, biochemically assisted whitening processes involving the application of different aqueous solutions were evaluated. Head rice yield was increased for all tested liquids (3.3–3.8% depending on liquid) for Gladio‐type brown rice treated with 0.5% liquid prior to whitening to 40 Kett using a lab‐scale horizontal friction‐type McGill whitener. However, the moistening led to increased caking in the McGill milling chamber. In comparative trials, the use of moistening solutions containing enzymes, sorbit, or sodium chloride instead of pure water delivered a slightly, but nevertheless, significantly higher degree of whiteness directly after milling while it did not result in a significant reduction in the number of broken kernels. Since average head rice yield has a 43% higher commercial value than broken kernels, the 3.6% improvement in milling yield achieved by adding 0.5% water would result in an estimated increase in profit for a 7.5 t/h rice mill of 0.83%. Practical applications Rice as a global staple food bears a critical role in human nutrition. At the same time, the quality of milled rice is a key buying and price criterion in rice‐consuming countries. One key quality criterion is the number of brokens in rice. Hence, it is critical for rice millers to minimize the degree of broken kernels. Biochemically assisted rice whitening for improving head rice yield is a combined biochemical and physical method to facilitate bran removal from brown rice. The main aim of the present study was to investigate the effect of biochemically assisted rice whitening on the number of brokens and to assess potential technological challenges resulting from the liquid addition.

Engineering, biochemical, and cooking characteristics of seven eminent cultivars of brown rice: Implication on development of food processing equipment

“…In various research studies, it has been testified that moisture content manifested by the grain has a noteworthy impact on its physical properties (Maldaner et al, 2021; Pandiselvam & Tirupathi, 2014). Numerous considerations associated with the overall physical, dimensional, milling, and cooking qualities of the rice cultivars (paddy and milled rice) are credibly influenced by the moisture content of the grain under deliberation (Schefer et al, 2021). For instance, Bhat and Riar (2016) postulated that to attain a superior milling capacity with a maximum yield of head rice, the moisture content of the grain turns out to be an indispensable parameter that needed to be closely monitored.…”

Moisture content‐dependent mechanical behaviors of rice by experiments and composite models in finite element simulation

“…Moreover, stress concentration has a significant impact on subsequent processing steps, which results in a large number of broken rice grains (Chen et al, 2021; Cheng et al, 2016). The loss rate in the process of processing paddy into brown rice is as high as 25%, and the loss rate reaches 70% when further processing brown rice into polished rice (Schefer et al, 2021). Therefore, improving the yield of polished rice has become a key problem nowadays (Gajanana et al, 2013; Graves et al, 2009; Schefer et al, 2021).…”

“…The loss rate in the process of processing paddy into brown rice is as high as 25%, and the loss rate reaches 70% when further processing brown rice into polished rice (Schefer et al, 2021). Therefore, improving the yield of polished rice has become a key problem nowadays (Gajanana et al, 2013; Graves et al, 2009; Schefer et al, 2021).…”

“…Therefore, improving the yield of polished rice has become a key problem nowadays (Gajanana et al, 2013;Graves et al, 2009;Schefer et al, 2021).…”

“…significant impact on subsequent processing steps, which results in a large number of broken rice grains (Chen et al, 2021;Cheng et al, 2016). The loss rate in the process of processing paddy into brown rice is as high as 25%, and the loss rate reaches 70% when further processing brown rice into polished rice (Schefer et al, 2021).…”