Comparative Study of Fractionation Technologies and Their Impact on the Nutritional and Functional Properties of Maize and Rice Fractions

Abstract

The two globally leading cereals, maize and rice, offer great potential for producing high-value fractions and biopolymers for diverse food and non-food applications. Wet- and dry-fractionation techniques are commonly used to concentrate specific kernel components, with process parameters adjustable to yield tailored functional fractions. This review provides a comprehensive analysis of the key biopolymers in maize and rice, their functional properties, and applications across sectors. It also examines both established and emerging fractionation methods, emphasizing how processing conditions influence nutritional and functional qualities. The interplay between kernel structure and process parameters is highlighted as a critical factor in optimizing yield and tailoring fraction properties. In wet-fractionation of maize, steeping conditions (time, temperature, acids, and SO2 concentration) and maize variety significantly affect protein and starch separation, fraction purity, and starch properties (pasting, gelling, and water solubility). Further, physical (e.g., ultrasonic and pulsed electric field) or enzymtic treatments have shown to increase wet-fractionation efficiency. In rice, dry-fractionation efficiency, especially of bran and head rice, is strongly affected by kernel shape and overall hardness as well as milling degree. Conversely, dry-fractionation in maize is typically used for particle size reduction, while wet-fractionation of rice is less common and often applied for soaking, solvent extraction milling, parboiling, or combined with dry grinding. Overall, the present study underlines the complex relationship between cereal structure, processing parameters, and final fraction properties. A deeper understanding of these interactions offers valuable insights into customizing processes for the efficient, targeted, and sustainable production of functional biopolymers and fractions from maize and rice.