Abstract:
In order to study the effect of storage temperature on the gelatinization characteristics of parboiled rice and explore its storage characteristics, low temperature (15℃,
RH 75%), normal temperature (25℃,
RH 75%) and high temperature (35℃,
RH 75%) were simulated as the storage conditions of milled rice. The storage period was 300 days, and samples were taken every 30 days. The gelatinization characteristics parameters (peak viscosity, trough viscosity, final viscosity, breakdown, setback, peak time, and gelatinization temperature) of parboiled rice and milled rice samples were measured by RVA, and correlation analysis and factor analysis of variance were carried out for the data. The results showed that the peak viscosity and breakdown of milled rice increased first and then decreased with the extension of storage time, while the trough viscosity, final viscosity, setback and gelatinization temperature increased gradually with the extension of storage time, and the peak time showed a small increase trend. The peak viscosity, trough viscosity, final viscosity, breakdown and setback of parboiled rice produced in the same batch of milled rice were lower than that of milled rice, and the peak time and gelatinization temperature were higher than that of milled rice. With the extension of storage time, the peak viscosity, trough viscosity, final viscosity and setback of parboiled rice increased first and then decreased. The higher the temperature, the greater the change range, and the breakdown, peak time and gelatinization temperature of parboiled rice were basically stable; Storage temperature had a significant impact on the gelatinization characteristics of parboiled rice and milled rice (
P< 0.01); The intersection of storage time and storage temperature had a very significant effect on the gelatinization characteristics of milled rice (
P< 0.01), but had no significant effect on the gelatinization temperature (
P> 0.05) and had a significant impact on the peak time (
P< 0.05) of parboiled rice. Storage time had significant correlation with other gelatinization characteristics indexes except peak viscosity and peak time of milled rice, and the absolute value of correlation coefficient was above 0.471. However, storage time had significant correlation with breakdown and peak time of parboiled rice, and had extremely significant correlation with gelatinization temperature, with the absolute value of correlation coefficient above 0.386.During the storage period, compared with the milled rice, the gelatinization characteristics indexes of parboiled rice were relatively less affected by the storage time, indicating that parboiled rice can better maintain its starch structure and gelatinization characteristics, and has good storage stability.