Mathematical modeling of starch gelatinization and some quality properties of parboiled rice based on parboiling indicators using RSM

Parboiled Paddy Drying with Different Dryers: Thermodynamic and Quality Properties, Mathematical Modeling Using ANNs Assessment

The effect of hybrid infrared-convective (IRC), microwave (MIC) and infrared-convective-microwave (IRCM) drying methods on thermodynamic (drying kinetics, effective moisture diffusivity coefficient (D_eff), specific energy consumption (SEC)) and quality (head rice yield (HRY), color value and lightness) characteristics of parboiled rice samples were investigated in this study. Experimental data were fitted into empirical drying models to explain moisture ratio (MR) variations during drying. The Artificial Neural Network (ANN) method was applied to predict MR. The IRCM method provided shorter drying time (reduce percentage = 71%) than IRC (41%) and microwave (69%) methods. The D_eff of MIC drying (6.85 × 10⁻¹¹–4.32 × 10⁻¹⁰ m²/s) was found to be more than the observed in IRC (1.32 × 10⁻¹⁰–1.87 × 10⁻¹⁰ m²/s) and IRCM methods (1.58 × 10⁻¹¹–2.31 × 10⁻¹¹ m²/s). SEC decreased during drying. Microwave drying had the lowest SEC (0.457 MJ/kg) compared to other drying methods (with mean 28 MJ/kg). Aghbashlo’s model was found to be the best for MR prediction. According to the ANN results, the highest determination coefficient (R²) values for MR prediction in IRC, IRCM and MIC drying methods were 0.9993, 0.9995 and 0.9990, respectively. The HRY (from 60.2 to 74.07%) and the color value (from 18.08 to 19.63) increased with the drying process severity, thereby decreasing the lightness (from 57.74 to 62.17). The results of this research can be recommended for the selection of the best dryer for parboiled paddy. Best drying conditions in the study is related to the lowest dryer SEC and sample color value and the highest HRY and sample lightness.

Effect of Parboiling on Phenolic, Protein, and Pasting Properties of Rice from Different Paddy Varieties

The present study evaluated the effect of parboiling on milling, chemical constituents, pasting and cooking properties of different paddy varieties. Parboiling decreased L^* and a^* values and increased b^* and head rice recovery. Parboiling significantly increased the protein content and antioxidant activity on a dry basis. Parboiling decreased whiteness, fat content, and paste viscosities. The parboiling process increased the hydrophobicity of rice from all the varieties. Parboiled milled rice showed higher free and bound phenolic acids as compared to unparboiled milled rice. Parboiled milled rice showed higher content of essential amino acid than unparboiled milled rice. Variety PB1121 was suited best for parboiling on the basis of total color (ΔE), protein content, essential amino acid, and phenolic acids among the evaluated paddy varieties. PRACTICAL APPLICATION: The present study revealed that parboiled milled rice had higher antioxidant activity, amino acids, ferulic acid, and p-coumaric acids. Indeed, parboiled milled rice showed better textural and nutritional properties and would be more suitable for canning, puffed rice and biryani (rice cooked with chicken/mutton).

The Optimization and Mathematical Modeling of Quality Attributes of Parboiled Rice Using a Response Surface Method

The response surface methodology was used to optimize the hydrothermal processing conditions based on the rice quality parameters of the Rong Youhua Zhan rice variety (Indica). The effect of soaking temperature (29.77, 40, 55, 70, and 80.23°C), soaking time (67.55, 90, 120, 150, and 170.45 min), and steaming time (1.59, 5, 10, 15, and 18.41 min), each tested at five levels, on percentage of head rice yield (HRY), hardness, cooking time, lightness, and color were determined, with R2 values of 0.96, 0.94, 0.90, 0.88, and 0.94, respectively. HRY, hardness, cooking time, and color increased with process severity while lightness decreased, although HRY decreased after reaching a maximum. The predicted optimum soaking temperature, soaking time, and steaming time were 69.88°C, 150 min, and 6.73 min, respectively, and the predicted HRY, hardness, cooking time, lightness, and color under these conditions were 73.43%, 29.95 N, 32.14 min, 83.03 min, and 12.24 min, respectively, with a composite desirability of 0.9658. The parboiling industry could use the findings of the current study to obtain the desired quality of parboiled rice. This manuscript will be helpful for researchers working on commercializing parboiled rice processes in China as well as in other countries.