Dynamic oscillation rheometry in combination with repeated freeze-thaw cycles(DORFT method)was applied to characterize the properties of the long-term starch retrogradation of rice flour gels from different four rice cultivars for sake brewing. Here, τ is a parameter of the tendency for long-term starch retrogradation obtained from the DORFT method, and these values of the gels(6%, w/w)from
Yamadanishiki, Gohyakumangoku, Kaminoho and
Mienoyume harvested during the growing year 2017 were 1.11, 2.06, 1.64 and 1.54, respectively. This indicated that
Gohyakumangoku was the most easily retrogradable rice at the gel concentration. Further, there were good linear relationships between τ and the gel concentrations in all four rice varieties, with the retrogradation rate of
Gohyakumangoku being the highest. Irrespective of the growing years from 2015 to 2017,
Yamadanishiki also had a good relationship between τ and the gel concentrations. While the enzyme digestibility of steamed rice from
Yamadanishiki growing years 2015 and 2017 was almost the same, these retrogradation rates were different. This implies that results of the enzyme digestibility of steamed rice do not always serve as indicators of the properties of long-term starch retrogradation.
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