IRRI SERVICE LABORATORIES
provides quality and efficient integrated laboratory testing services and expertise
Head rice yield
Head rice yield (HRY) is the primary factor used to determine rice milling quality. HRY is defined as the percentage of paddy rice that retains at least three-quarters of the original length of the grain after milling. Brown rice and milled rice percentages are also reported.
Estimated moisture content is taken from at least 10% of the number of samples. The ideal moisture content to proceed with determining HRY is 12 % – 14 %. About 150 g of cleaned paddy rice is dehulled, milled, and sorted for head rice; weighing of the samples are done between these three steps.
Note: For head rice yield determination, the sample weight required is at least 150 g of paddy rice placed in a paper bag. In order to keep the integrity of the customers' samples, senders are requested to place them in secured plastic boxes.
Cooper NTW, Siebenmorgen TJ. Rice Quality and Processing. 2007. http://www.uark.edu/ua/uarpp/Publications/Milling/Cooper%20and%20Siebenmorgen%202007%20Cereal%20Chem.pdf
Rice Quality Training Manual from IRRI. rkb.irri.org/.../images/.../Rice%20Quality%20Reference%20Manual.doc
Sreenivasulu, N. (2018). Rice Grain Quality: Methods and Protocols. New York, NY: Humana Press.