Quality improvement of refrigerated ready‐to‐eat cooked brown rice by adding gellan gum and trehalose with ohmic heating compared to conventional cooking method

Abstract

There has been an increasing demand for ready‐to‐eat rice meals with superior quality and nutritional values. In this study, food additives and ohmic heating method were applied with the main objective to raise the quality of refrigerated ready‐to‐eat cooked brown rice compared to that of conventional method. Four rice varieties including RD 43, Riceberry, KDML 105, and RD 6 were investigated. Effects of adding gellan gum at 0.1%–0.3% w/w and trehalose at 1%–3% w/w on electrical conductivity, starch retrogradation level, and energy consumption were investigated. The results indicated that the addition of gellan gum or trehalose decreased the electrical conductivity. Gellan gum addition could retard starch retrogradation more efficiently than trehalose. Brown rice samples cooked using ohmic method had significantly lower retrogradation levels than their counterparts. Ohmic cooking system in the present work consumed around 1.7–2.6 times more electrical energy compared to that required using conventional method. Practical applications There is increased demand by health‐conscious consumers for brown rice products due to their nutrient contents. The processing of cooked brown rice to make a refrigerated ready‐to‐eat meal is an interesting approach to raise the market value of brown rice and is compatible with the modern lifestyle. The current study proved that gellan gum or trehalose in refrigerated ready‐to‐eat cooked rice meals can impede starch retrogradation during storage. Furthermore, the ohmic method can be applied in cooking brown rice, resulting in significantly lower retrogradation levels in the cooked brown rice after storage.