| Abstrakt: |
Introduction. Steaming in rice-parboiling causes gelatinization and protein disintegration in the endosperm changing its appearance and strength by fused gelatinized starch granules that disrupt protein bodies. Materials and methods. Steaming-periods on grain strength and appearance of FARO64, FARO65, FARO66 and FARO67 rice varieties were evaluated. Each variety was divided into 5-parts; 4-parts parboiled and steamed for 5, 10, 15 and 20 mins (at constant temperature and atmospheric pressure), while the 5th portion served as control. Results and discussion. Steam application had a significant effect (p<0.05) on grain strength. Optimum strength was recorded at 20 mins steaming-period in FARO64, FARO65 and FARO66, while FARO67 had highest strength at 15 mins with values ranging from 61.53N to 225.83N. FARO65 had reduced L* value, though all varieties kept the yellow colour with the steaming-time. Only FARO64 maintained a* values with steaming-time. For length, FARO67 changed to very long, while FARO64, FARO65 and FARO66 changed from medium to long with a value range of between 6.33 mm and 7.57 mm. The width values (1.98-2.62 mm) equally changed, as all varieties increased with steaming-time. All except FARO64 reduced in thickness with steaming-time. Shape of FARO64 changed from medium to slender; FARO65 and FARO66 maintained medium shape, while FARO67, from slender to medium. Thousand grain weights were between 15 and 24; FARO64, FARO66 and FARO67 had reduced mean-value, while FARO65 increased. Conclusion. Parboiling reduces raw rice breakage rate, and improves strength, colour and appearance. Gelatinization temperature influences rice quality. [ABSTRACT FROM AUTHOR] |
