Effects of postharvest operations on the gelatinization and retrogradation properties of long-grain rice.
Fan, J., Marks, B. P., Daniels, M. J. and Siebenmorgen, T. J.
Transactions of the ASAE. Vol: 42 Issue: 3 Pages: 727-731.
1999
บทคัดย่อ
The effects of rough rice pre-drying, drying, and storage treatments on the gelatinization and retrogradation properties of long-grain rice (cv. Cypress) were studied via differential scanning calorimetry (DSC). The experimental variables included two pre-drying conditions (immediate and delayed drying), two drying conditions (high and low air temperatures), and four storage treatments (no storage, and storage at 4, 21, and 38 degrees C for 20 wk). Gelatinization of the rice flour in water occurred at temperatures from 73 to 86 degrees C, with an enthalpy of 8.3 to 9.7 J/g. Storage temperature had a significant effect on the gelatinization characteristics. Rice stored at 38 degrees C exhibited higher (p < 0.0005) gelatinization enthalpy and peak temperature than did rice stored at 4 and 21 degrees C. Pre-drying treatments had no significant effect on the gelatinization enthalpy and peak temperature, but did on the onset temperature (P < 0.05). The pre-drying and/or drying treatments had significant (p < 0.05) effects on the retrogradation onset and conclusion temperatures of gelatinized rice. Storage of rough rice significantly (p < 0.0001) increased retrogradation enthalpy, but did not affect the peak temperature of the retrogradation endotherm.