Rice Flashcards
Rice Latin name
Oryza sativa L.
World production
755 million tonnes. China, India, Indonesia, Bangladesh, Vietnam, Thailand, Myanmar, Philippines, Brazil, Japan, USA.
Kernel Characteristics
Covered caryopsis - rice is harvested with hull attached. Barley and rice are the only cereals which retain their hulls.
Rice and Oat hull
Rice and oat’s hull is loosely attached to the pericarp so easy to remove. Barley’s hull tightly cements to the pericarp thus hard to remove.
What is “Brown Rice”
Brown rice is simply dehulled rice.
Brown Rice chemical constituents
80% starch
11% protein
3% fat
What is “Paddy Rice” or “Rough Rice”
Paddy/Rough rice is rice with the hull still intact. About 20% of the grain is hull.
What is White Rice
rice after it has been milled. to obtain white rice from brown rice, the bran is polished off.
Does the hull have value for animal feed?
No – hull is high in lignin and silica – low animal feed value.
How are market classes differentiated
delineated according to grain length.
differences in grain length are associated with different in the composition and physiochemical characteristics of the starchy endosperm.
Market Classes of Rice (2)
Tropical Long Grain (oryza sativa indica). larger market.
Temperate Short Grain (Oryza sativa japonica)
Medium grain varieties are inter-race crosses.
Rice Processing
Rice milling separates the hull from the caryopsis (dehulls), removed the bran and germ (fines), and recovers starchy endosperm intact (white rice)
Rice Milling
- Dehulling – rubber rollers. easy since lemma and palea (plumes) not tightly adherent to pericarp
- Abrasive Milling – cone mill with abrasive surface grinds bran and germ off to yield milled rice. Fines removed by aspiration.
- Polishing - rubs/grinds way inner bran resulting in shiny white rice. Fines removed by aspiration.
How are Rice Grits utilized
Broken rice pieces – Brewing, pet food, cereal
How is Rice flour used
gluten free baked goods,
How is the bran/polish used
rice bran oil and meal, high protein flour.
What is rice hull used for
fuel, insulation, bedding.
What is Parboiled/Converted Rice
Parboiled rice has been partially cooked (boiled) and dried before it is processed.
Converted Rice is steeped/steamed and dried before processed.
Why is some Rice Parboiled/Converted?
It leaches water soluble nutrients from the bran into the starchy endosperm
Reduces losses during milling, polishing and cooking by hardening endosperm.
Improves shelf life as lipases in residual aleurone are inactivated
What is undesirable about Parboiling/converting Rice
Leaches bran and hull pigments into the endosperm. yellow rice.
Instant Rice
Partial pre-cooking and subsequent flash drying of brown or polished rice.
Drying leaves grain porous which hasten water uptake.
Texture of rice is affected.
