No abstract

The term 'micronization' is often used to refer to a process of heat treatment of grains at high temperature for a relatively short time processing using near-infrared radiation. Recently there is an increasing interest in the application of micronization as a processing technology for grains. When cereals/legumes with sufficient moisture are subjected to micronization, some beneficial changes like partial gelatinization of starch, inactivation of enzymes that are responsible for the degradation of quality and denaturing of antinutritional factors are observed. The partial gelatinization due to micronization improves starch digestibility and palatability and reduces the cooking time without significantly affecting other nutrients present in grains. Micronization is applied in the commercial production of quick cooking pulses, flaked cereals and toasted products. This review mainly deals with recent studies on micronization of pulses and cereals used as food and feed and the effect of micronization on product quality and cooking characteristics.

Micronization of maize varieties viz. Nityashree (NAH-2049) and Arjun (EH-434042) was carried out in a near-infrared (NIR) based system. Infrared (IR) processing conditions such as moisture content and time of exposure were standardized to inactivate peroxidase and lipase enzymes and, to improve starch digestibility. Micronization of maize at 200°C for 4 min resulted in 16-20% increase in rapidly digestible starch (RDS) content. The process was effective in completely inactivating peroxidase enzyme and reducing lipase activity by 83-86%. The process did not induce any marked changes in total carbohydrates and protein contents. Reduction in pasting viscosities, peak viscosity (PV), and set back viscosity (SV) of micronized maize flour indicated partial gelatinization of starch. Micronized Arjun flour exhibited higher RDS content, which was correlated with lower viscosity profile values compared to Nityashree flour. Inactivation of enzymes in micronized maize provides the scope for shelf-life extension of flour. Improvement in RDS content increased water absorption capacity, and low viscosity profile provides an opportunity for its inclusion in preparing calorie dense foods having high solids concentration.