The effect of low shear on the development of fortified extruded rice products

Abstract Fortified extruded rice presents promising commercial opportunities for delivering nutrients and other functional ingredients to the global rice consuming population. Its formulation may be changed to suit the nutritional requirements of different target markets. The objective of this study was to develop a product line of prototypes that resemble the texture and appearance of natural rice grains, and have good retention of added nutrients. Extruded fortified rice was manufactured in a controlled mechanical shear extrusion process by first combining a mixture of fortified rice flour and water in a pre‐conditioner, then advancing the mixture along the length of an extruder barrel with a terminal extrusion die inserts in the shape of rice kernels. Extruded rice grains were evaluated for the degree of gelatinization, texture profile, and starch depolymerization. Retention of added vitamins and minerals was also measured. The cooked extruded grains had comparable texture to cooked commercial rice with good sensory characteristics. Based on the results, the key strategy in producing good quality extruded fortified starch is to achieve as high a degree of starch gelatinization in the extruded rice kernel as possible without inducing excessive starch breakdown.