Selection of drying method and milling pattern for obtaining efficient postharvest technology of long grain rice (Oryza sativa L. var. Ciherang) withpreserved nutritional quality

Generally, long grain rice is vulnerable to cracking during milling, whilst others claimed that paddy drying methods influence the head rice recovery. Thus, this work aimed to find out the suitable long grain rice paddy drying method and milling pattern to enhance head rice recovery with preserved nutrient content. A set of rough paddy rice drying tests utilising thin layer, oven and sun drying methods were carried out. Subsequently, the dried rough rice grain was milled employing different dehusking (H), separation (S) and polishing (P) patterns to attain white rice. For comparison, the white rice samples attained were analysed for their head rice recovery, broken rice recovery, chips recovery, whiteness and nutrient content. Milling patterns greatly influenced the total, head rice, broken rice and chips recoveries. Milling pattern, which includes one dehusking, one segregation and one polishing (H–S–P) produced the greatest total and head rice recoveries. Even though the milling pattern appreciably influenced the rice samples' whiteness, their whiteness values still fell within the acceptable range preferred by Southeast Asian consumers (39-47 score). Milling of dried rough rice attained from a thin layer and sun drying on a concrete floor and white tarpaulin produced similar total recovery (67.19%) and head rice recovery (51.40%). Nevertheless, milling of rough rice dried using oven and sun drying on black tarpaulin produced marginally lower total recovery (66.89%) and head rice recovery (50.25%). The white rice contained remarkably lower moisture, ash, protein and lipid than those of manually dehusked rice. However, the white rice possessed considerably higher carbohydrate and amylose contents. The use of thin-layer or sun drying on concrete floors succeeded by milling with H–S–P pattern resulting in the greatest head rice recovery with tolerable whiteness and nutrient content. This postharvest technology provides easy, efficient and economical implementations for small- and commercial-scale rice enterprises.