Cereal and Pulse Processing

Study Notes

Paddy varieties exhibit diverse quality characteristics; key focus includes parboiling techniques and physico-chemical changes.
Rice milling methods divide into traditional (hand milling) and modern (mechanized processes).
Wheat and maize milling involves understanding basic concepts, by-products, and product applications.
Millets such as sorghum, finger millet, and pearl millet require specific milling methods to maximize quality output.

Bran: Coarse outer seed covering, rich in fiber and protein; common types include corn, rice, and wheat bran.
Flour: Fine texture, primarily gluten and starch; low in crude fiber; rye and wheat are prevalent types.
Germ Meal: High in lipids and protein; prevalent forms include corn and wheat germ meal.
Gluten Feed and Meal: By-products from wet corn and sorghum milling; classified as protein sources.
Grain Screenings: Mixture of dust, chaff, and broken grains; nutritional value varies with composition.
Groats: Grain seeds without hulls, commonly oat and rice groats; higher nutritional value than original grain.
Corn Hominy Feed: Includes corn bran, germ, and flour; higher in protein and fiber than corn grain.
Grain Hulls: Low energy, low protein, high fiber outer covering; common from oats and rice milling.
Middlings: By-products from flour production, comprising bran, shorts, and germ; commonly rye and wheat.
Rice Polishings: Residue from polishing; low crude fiber but high in crude fat and thiamin.
Wheat Shorts: Consist of bran, germ, and flour; maximum crude fiber content is 7%.

Products include maize starch, sorbitol, liquid glucose, dextrose monohydrate, dextrose anhydrous, gluten, and maltodextrin.

Separation: Raw materials like corn are milled to separate starch from other components; enzymes are utilized to enhance this process.
Liquefaction: Involves cooking starch to dissolve granules; the mix is treated with amylase at elevated temperatures and specific pH for 2-4 hours.
Saccharification: Starch is cooled and treated with fungal glucoamylase, resulting in a high dextrose content.
Isomerization: Glucose is transformed into fructose; adjustments in pH and the addition of magnesium salts optimize enzyme activity.

Safe moisture levels for sorghum storage should be between 10-12%; this prevents mold growth and insect attacks, protecting against mycotoxins like aflatoxins.

Various methods exist for milling pulses, including dry and wet methods; pre-treatment involves soaking in oil or water for several days to enhance processing efficiency.