Drying modeling, cooking characteristics, pasting properties, and crystallinity of fortified rice kernels

Effect of microwave drying and tempering on color attributes, fissure formation, and cooking characteristics of fortified rice kernels

Fortified rice kernels (FRK) are a vitamin-mineral enriched extruded rice-shaped product blended with raw or parboiled rice in a 1:100 ratio to prepare fortified rice. In FRK manufacturing, drying is one of the essential steps that affect the quality of FRK. In the present study, the microwave technique was explored to dry FRK continuously at 180, 360, and 540 W and with the tempering (1, 2, and 3 min) at 180 W to evaluate the effects on the drying curves, color attributes, fissure formation, and cooking characteristics. Thin layer modeling suggested the Two-term exponential model (two parameters), diffusion model (three parameters), and Midilli Kucuk (four parameters) as the best models to predict moisture based on Akaike and Bayesian information criteria. The higher MWP (360 and 540 W) significantly lowered the L* and WI while increasing the a*, b*, and BI compared to 180 W, which was undesirable. Image processing showed fissures in all FRK samples; however, 1 min and 2 min tempering could somewhat restrict the fissure. The fissures caused higher solid losses and increased splitting of kernels during cooking. It can be concluded that the low MWP (< 180W) with appropriate tempering time can be used to dry FRK.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05871-4.

Effect of Marjoram Leaf Powder Addition on Nutritional, Rheological, Textural, Structural, and Sensorial Properties of Extruded Rice Noodles

Food-to-food fortification is an emerging technique to enrich the micronutrients in foods. Pertaining to this technique, noodles could also be fortified with natural fortificants. In this study, marjoram leaf powder (MLP) at a level of 2-10% was used as a natural fortificant to produce fortified rice noodles (FRNs) through an extrusion process. The MLP addition caused a significant increase in the iron, calcium, protein, and fiber in the FRNs. The noodles had a lower whiteness index than unfortified noodles but had a similar water absorption index. The water solubility index increased significantly due to the higher water retention ability of MLP. A rheological study showed a minimal effect of fortification on the gelling strength of the FRNs at lower levels. The microstructural studies found incremental cracks, which facilitated a lower cooking time and hardness but had an insignificant effect on the cooked noodle texture. Fortification improved the total phenolic content, antioxidant capacity, and total flavonoid content. However, no significant changes in bonds were observed, but a reduction in the noodles' crystallinity could be seen. The sensory analysis of the noodles reflected a higher acceptability of the 2-4% MLP fortified samples compared to the others. Overall, the MLP addition improved the nutritional content, antioxidant activity, and the cooking time but slightly affected the rheological, textural, and color properties of the noodles.