Hydrocolloid sour taste control in pasteurized rice.

The effects of kappa (κ)-carrageenan and carboxymethyl cellulose (CMC) in controlling the sourness intensity perception of added acetic, citric, and tartaric acids in solutions for steeping and cooking of rice intended for pasteurization were determined. The rank order of added acids (0.10 and 0.20 % w/v, pH 4.00) in the initial development of acidified hydrocolloid solutions was: acetic > citric > tartaric. The final rice acidification protocols included steeping and cooking of Japonica rice cultivar Kanto in tartaric-acidified hydrocolloid solutions of κ-carrageenan and CMC (0.30 % w/v, 50 ± 2 °C for 1 h) at pH 2.75 and 2.90, respectively. The acidified cooked rice in pouches were pasteurized in boiling water (100 °C) to reach 95 °C for 5 min. The pasteurized products were categorized under acidified foods with final Aw < 0.85 and pH < 4.00. No perceivable sour tastes from 1 to 12 week storage at 28 ± 2 °C were noted in the pasteurized rice products. The shelf-stable pasteurized products were described as white, translucent, with distinct natural rice aroma and flavor, firm, and slightly elastic mouth and hand feel.