Milling

MILLING PROCESS SEPARATES THE ENDOSPERM FROM THE OTHER KERNEL PORTIONS Milling is the process of dehulling and grinding grains such as oats, wheat, rice, and corn into smaller pieces or flours to improve palatability, reduce cooking time, and create food products. Grain Flour s e g a t s 3 Cleaning & conditioning Crushing or breaking Reduction 1. Cleaning & conditioning Removing all impurities from the grain and preparing it for milling. 2. Crushing or breaking Breaking down the grain in stages to release its constituent parts. 3. Reduction Rollings and siftings are used to refine the flour and separate it into different categories, which are referred to as streams. Steps involved in milling process Processing machinery Grinding equipment: 'Roller flour mill' - The wheat is ground between two cast rolls (break rolls) that rotate against each other. Screening equipment: 'Square plansifters &rotary sieves' - Generally used for screening and grading after grinding. It can also be used as checking sifter. Roller Mill Flour purifier: 'Purifier' - SeparateS clean farina, or coarse endosperm, from fine bran or compound particles to feed the primary reduction rolls. Flour Purifier Source:https://www.abcmach.com/grain-processing/flour-milling/purifier.html Plansifters ANATOMY OF GRAIN Bran The bran is the outermost layer of the kernel, making up about 14.5 percent of total kernel weight. Endosperm The endosperm makes up the majority of the kernel weight – 83 percent. Germ The germ is the smallest part of the kernel – 2.5 percent of total weight. It is the embryo of the wheat plant. Most flours are made from the endosperm after removal of the bran and germ. Milling reduces the nutritional value of flour by removing a large proportion of the minerals and vitamins, found in whole-wheat kernels. Flour is enriched with nutrients to compensate for the loss of nutrients during the milling process. The flour yield, or percentage extraction rate, is the number of parts flour by weight produced per 100 parts wheat milled. Milling By-Products The by-products from wheat milling process are known as wheatfeed. It comprises of : 1. Bran 2. Coarse residue from break grinds 3. Fine feed, purifier particles 4. Reduction grinding. Compound animal feeds contain bran and fine wheat feed.