COMPARATIVE EFFECTS OF TRADITIONAL AND MODERN RICE ROCESSING TECHNOLOGIES ON NUTRITIONAL COMPOSITION, PHYTOCHEMICAL RETENTION AND FUNCTIONAL PROPERTIES OF RICE IN NORTHEASTERN NIGERIA

Abstract

This study assessed the rice processing methods used in Northeastern Nigeria and examined their effects on the physical, functional and proximate qualities of processed rice. A survey was conducted in 12 rice milling centres across Adamawa, Bauchi, Borno, Gombe, Taraba and Yobe States. Rice samples representing traditional, small-scale mechanized and semi-industrial processing methods were collected and analysed using standard procedures. Proximate composition, functional properties, milling recovery and selected physical quality characteristics were determined. The data were subjected to analysis of variance, and significant differences were separated using Tukey’s HSD test at P < 0.05. The survey indicated that more than half (58.3%) of the processors used improved processing technologies, although traditional methods were still practiced. Small-scale mechanized milling was the most widely used method (58.3%). Modern commercial mills recorded the highest milling recovery (68.9%), followed by locally fabricated mills (61.7%) and traditional stone mills (55.3%). Modern milling also produced more uniform whiteness (83.3%) and a lower occurrence of foreign materials (16.7%) than stone milling, which recorded 25.0% and 66.7%, respectively. The proximate analysis showed clear differences associated with processing methods. Parboiled milled rice generally retained higher levels of protein (10.85–13.96%), fibre (4.57–10.92%), fat (1.21–2.52%) and ash (1.13–2.22%) than raw milled rice, whereas raw milled rice generally had higher carbohydrate contents (78.71–82.65%). Functional properties also varied among rice varieties and processing treatments, particularly with respect to gelatinization and viscosity characteristics. Overall, the findings indicate that appropriate parboiling, together with improved and controlled milling practices, can enhance nutrient retention, reduce grain breakage, improve milling recovery and produce rice with better physical and functional qualities. The study recommends investment in improved processing facilities, regular training for processors, standardization of parboiling and milling procedures, and stronger quality-control measures to improve the nutritional quality, market value and competitiveness of locally processed rice in Northeastern Nigeria.