Standards and grades for milled rice

Standards can be defined as a quantitative way by which we measure and compare certain quality characteristics. This measured comparison of recognizable quality characteristics can described as ‘grading’.
To date, there are few universally accepted international standards for paddy and milled rice. This is primarily due to a differences in emphasis on the importance of grading paddy and milled rice quality among countries. However, national standards exist and are being used as a marketing basis. As an example, the table shows national standards for milled rice in the Philippines.

In general, grading factors for paddy are (1) purity, (2) foreign matter, (3) defectives and (4) moisture content. For milled rice, the characteristics considered for grading are (1) head rice, brokens and brewers percentages (2)defectives, (3) foreign matter, (4) presence of paddy and (5) moisture content.
Objectives of establishing standards and grades
1. to ensure only edible rice reaches the consumer;
2. to improve postharvest practices so as to eliminate or reduce waste;
3. to improve agronomic practices to increase farm yields;
4. to improve processing practices for better milling recoveries and for market expansion and
5. to protect consumers from price/quality manipulation.
In relation to the first objective, the characteristics such as moisture content, foreign material, seeds and discolored (damaged) grains are important considerations in assuring that only edible rice reaches the consumers. By setting standards for degree of milling, broken rice content, moisture and damaged grains, the second objective is addressed. Better threshing and drying, and improved storage facilities are expected to emerge to meet the required standard. The third objective provides incentives to the farmer/agricultural scientist to optimize production by considering standards for chalkiness, varietal purity, foreign seeds, immature grains and red rice. The fourth objective provides a measure of the miller’s success in delivering high milling recovery and allowing the market expansion. Characteristics considered are standards for degree of milling, broken rice, paddy kernels and foreign matters. Finally, standards which clearly identify to consumers the true value of their purchases will provide the protection required against the possibility of unfair trading practices.
Comparison of rice mill output
Select a homogenous sample of paddy and run trials with different husking/whitening/polishing equipments, such as Satake abrasive mill, an Engleberg Rice Mill, a one-pass rubber roll mill. Input results using the sheet. Make a comparative analysis of the results obtained.
· Moisture content
· Head rice percentage
· Brokens
· Chalkiness
· Whiteness
· Milling degree
· Heat damaged/discolored grains
Quality of milled rice
Sample 1
Sample 2
No.
grains
(start)
No.
grains
(finish)
(%)
No.
grains
(start)
No.
grains
(finish)
(%)
Moisture content
Head rice
Broken
Chalkiness
Whiteness
Milling degree
Discolored grains
Grade the milled rice samples based on the National standards of milled rice in the Philippines. Take recommendations on improving the paddy and rice grade.