Rice Quality Training Manual 12

Rice Quality Training Manual
8.0 Measurements of chemical characteristics milled rice
Amylose content.
Twenty grains are selected and ground in the UDY Cyclone Mill. Amylose content is analyzed using the simplified iodine colorimetric procedure. Samples are categorized into low, intermediate and high based on the following grouping:
Category %Amylose Content
Low 10-20
Intermediate 20-25
High 25-30
Gelatinization temperature is measured using alkali-spreading value. The alkali digestibility test is employed. Grains are soaked in 1.7% KOH and incubated in a 30oC oven for 23 hours. Measurement ranges based on the following:
Category Temp ranges (oC) Alkali Spread
Low 55-69 6-7
Intermediate 70-74 4-5
High 75-79 2-3
Gel consistency.
Two to 10 grains are selected and ground separately in the Wig-L Bug. Gel consistency is measured by the cold gel in a test tube, being held horizontally, for one hour. Measurement ranges and category are as follows:
Category Consistency, mm
Soft 61-100
Medium 41-60
Hard 26-40