Germinated parboiled brown rice (GPBR) is a healthy Thai food. To extend the quality of GPBR cv. KDML 105 with 8.06% moisture content, the effects of three packaging conditions on the characteristics of GPBR were investigated. GPBR in laminated (nylon/LLDPE) bags was sealed as follows: vacuum-sealed, 40% N2-sealed with 60% CO2 (60% CO2+40% N2), or 100% N2-sealed before storage under ambient conditions (30±2°C, 70±5% RH) for 15 months. GPBR in all the packages exhibited delayed fungal proliferation and very low aflatoxin B1 contamination (<0.82 μg/kg). The 100% N2-sealed package was the best treatment to preserve GPBR quality, as indicated by the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity and free fatty acid content as well as the least rancidity and brownness. As observed through a scanning electron microscope, compared with vacuum-sealed packages and those sealed with 60% CO2+40% N2, the lowest hardness texture and the least elongation of cooked rice in 100% N2-sealed package were linked to a lesser compact GPBR endosperm ultrastructure.
Keywords: 100% N2; aflatoxin B1; parboiled rice; storage.