Changes in Cracking Behavior and Milling Quality of Selected Australian Rice Varieties Due to Postdrying Annealing and Subsequent Storage

Abstract

This study investigated the effect of drying temperatures, annealing regimes, and storage conditions on the level of rice kernel fissuring, mechanical strength, and head rice yield of three Australiangrown rice varieties, namely, Kyeema (long grain), Amaroo, and Reiziq (medium grains). Paddy samples were dried at 40, 60, and 80 C and then annealed for 0, 40, 80, and 120 min at the same drying temperature. It was found that annealing slightly improved the head rice yield with an increase in stiffness of rice kernels. The number of fissured kernels decreased with prolonged annealing duration of 80-120 min. During the storage period of up to 4 months at 4, 20, and 38 C, all measured parameters, such as percentage of fissured kernels, hardness, stiffness, head rice yield, and pasting properties, also showed increasing trends. A relatively rapid change in these physical properties of all rice samples was observed during storage at 38 C. A significant increase in stiffness of rice during storage at 38 C suggested that physical aging occurs during storage of rice below its glass transition temperature (55 C).

Effects of Rice Aging on Its Main Nutrients and Quality Characters

“…It was also found that the lower molecular weight polypeptide decreased with the increase of storage time, while the higher molecular weight polypeptide increased (Park et al, 2012;Chrastil, 1990). More importantly, the content of acetic acid soluble protein in milled rice decreased during 7 years of storage (Bolling et al, 1977;Bolling et al, 1978;Mangrauthia et al, 2017). During the aging process, the protein content of rice grain changed slightly, but the soluble nitrogen decreased continuously.…”

Modeling heat and mass transfer–induced stresses in germinated brown rice kernels during fluidized bed drying

“…Golmohammadi et al [40] and Truong et al [41] reported that the tempering could reduce the rice fissuring significantly and subsequently improve the mechanical properties of rice such as hardness and toughness. However, although the tempering can prevent the rice fissuring, but the termination of drying at 30 s would be difficult if the dryer was operated continuously since the residence time in this dryer, approximately 3 or 4 minutes, was relatively long in the commercial dryer.…”

Physical Modification of Food Starch Functionalities

“…Annealing may be conducted as a single-or multistep process , Nakazawa & Wang 2003, Shi 2008, Gomand et al 2012; in a dual process prior to or following HMT (Adebowale et al 2009;Chung et al 2009aChung et al , 2010; in situ within cereal grains and potato tubers during cultivation, processing, and/or storage Tester et al 1999Tester et al , 2005Genkina et al 2004;Kiseleva et al 2004;Piecyk et al 2009;Truong et al 2012); within whole-tissue flours (Zhou et al 2003(Zhou et al , 2010Cham & Suwannaporn 2010;Chung et al 2012a,b); prior to or following chemical modification (Song et al 2011, Majzoobi et al 2012; following acid hydrolysis (Brumovsky & Thompson 2001, Lin et al 2009); after starch fermentation (Gomes et al 2010); or in conjunction with nixtamalization (Figueroa et al 2013a,b). Annealed flours have been evaluated for their ability to improve the characteristics and properties of various noodles (Hormdok & Noomhorm 2007, Cham & Suwannaporn 2010).…”