The Retrogradation of Canned Rice During Storage

The retrogradation of canned rice products from three milled rice varieties, i.e., Thai Hom Mali (17.25% amylose, db.), Kaotahang (33.52% amylose, db.) and Koshihikari (15.55% amylose, db.) during storage at room temperature (270-290C) for 8 months was conducted. Canned rice was sterilized at 116 °C with F0 1 and 5 min. Retrogradation of gelatinized canned rice was studied by measuring hardness of rice kernel with Modified Single Kernel method. It was found that during storage the hardness of the rice kernels increased with the duration of the storage time (r=0.48 at p<0.05). Canned rice produced from high amylose rice variety (Kaotahang) had significantly higher retrogradation than the low amylose rice (Thai Hom Mali) (r=0.85 at p<0.01). Comparing the effects of sterilization (F0) and storage time on hardness of the low amylose rice varieties,
Koshihikari (L/W= 1.67, short grain) and Thai Hom Mali rice (L/W =3.19, long grain), both varieties had similar chracteristics of retrogradation throughout the storage time even though the L/W ratio was different. The hardness of rice kernel sterilized at F0 5min was lower than at F0 1min. The longer the rice products were stored, the higher the retrogradation (r = 0.90 at p<0.01).
Keywords: retrogradation, hardness, canned rice, storage
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E-mail: knwoaith@kmitl.ac.th