Preparation of Enzyme-Rich Fiber-Regulated Flour
Cereal malt is a primary product and requires further processing in different ways for various end uses. During germination, the endosperm undergoes physiological, biochemical, and textural modifications (MacLeod, 1967; Briggs and McDonald, 1983; Oh and Briggs 1989; Sa and Palmer, 2004; Go malting, 2006; Priest and Stewart, 2006). The seed coat or husk of cereal malt, specifically that of rice and barley, is nonedible and contains high amount of silica. Bran from other cereals also contains some of the antinutritional factors such as phytates, oxalic acid, and polyphenols. Hence, the husk and bran need to be separated from the malted seed to prepare edible malt flour. This has special significance specifically when the malt is intended to use for the enteral foods. Generally, rice (paddy or rough rice) is first dehusked in a rice sheller, and then the brown rice is debranned to a desired degree in rice pearlers or polishers (Wadsworth, 1991). On the other hand, the seed coat of barley is separated in specially designed pearlers (Peterson, 1994). Finger millet has soft endosperm covered with tough bran, and pearling or polishing of millet is not possible because its endosperm pulverizes during pearling. Hence, refined flour from millet is prepared by adapting moistening, grinding, and sieving techniques (Desikachar, 1980; Malleshi and Desilachar, 1981a; Reddy et al., 2004).
Malting modifies the endosperm texture and renders it highly friable, thereby altering its milling characteristics (Henry and Cowe, 1990; Hoseney, 1994; Priest and Stewart, 2006). A little impact or friction on malted grain causes breakage and even pulverizes the modified endosperm along with bran. Moreover, the fully modified (enzyme-rich) portion of the endosperm is softer than its less modified portion. Hence, the enzyme-rich portion of the endosperm easily pulverizes and mixes with husk and bran fractions during milling. Heat generation (that occurs generally during milling) while milling the malt should be minimum to prevent possible heat damage to the enzymes. These factors indicate that for milling of malted cereals the conventional cereal milling technologies require modifications.
KeywordsSeed Coat Dietary Fiber Mung Bean Amylase Activity Brown Rice
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