Effects of Postharvest Parameters on Functional Changes During Rough Rice Storage

Abstract

Cereal Chem. 78(3):354-357The expansion of value-added uses for rice has created a demand for quantitative models of functional changes during postharvest handling. Consequently, this study evaluated the effects of postharvest parameters on the functional properties of long-grain (cvs. Cypress and Kaybonnet) and medium-grain (cv. Bengal) rice. The experimental treatments included rough rice drying conditions (low vs. high temperature drying), storage moisture content (10, 12, and 14%), storage temperature (4, 21, and 38°C), and storage duration (up to 36 weeks). Milling, cooking, and amylograph pasting properties were analyzed. Polynomial models (up to third-order) were developed to describe the effects of postharvest factors on the functional properties. Drying treatments, storage moisture content, and storage duration affected (P < 0.05) all of the functional properties. Storage temperature influenced (P < 0.01) cooking and pasting properties, but not milling properties. Overall, there were significant interactions among the postharvest parameters. Additionally, these factors were related to the functional properties by higher-order relationships.Publication no. C-2001-0416-03R.

Changes in physicochemical properties of organic hulled rice during storage under different conditions

“…Consistent results were found in earlier studies. For short term storage, Pearce et al (2001) investigated pasting properties of the flours from milled rice cv. Cypress, Kaybonned and Bengal prepared from the aged paddy.…”

“…However, fluctuation in RVA parameters, especially peak viscosity, of the rice stored for 1-6 months, was reported (Pearce, Marks, & Meullenet, 2001;Soponronnarit, Chiawwet, Prachayawarakorn, Tungtrakul, & Taechapairoj, 2008;Wiset, Srzednicki, & Driscoll, 2003). Apart from storage time, the extent of these changes also depends on other factors, including amylose content of rice and storage temperature (Pearce et al, 2001;Sowbhagya & Bhattacharya, 2001;Zhou et al, 2003). Mechanisms underlying physicochemical property changes have been proposed, e.g., enzymatic and non-enzymatic reactions of starch, proteins and lipids in the rice kernel, including starch and lipid hydrolysis by amylase and lipase, respectively (Dhaliwal, Sekhon, & Nagi, 1991), formation of disulphide bridges in oryzenin (Chrastil, 1990), and formation of amylose-lipid complexes (Juliano, 1985).…”

“…Data from differential scanning calorimetry (DSC) and the Rapid Visco Analyzer (RVA) indicated that longer storage time, usually more than 6 months at ambient temperature, resulted in increasing gelatinisation temperatures, pasting temperature, and setback while it led to a decrease in peak viscosity and breakdown of the flours prepared from aged milled rice (Sowbhagya & Bhattacharya, 2001;Tulyathan & Leeharatanaluk, 2007;Zhou, Robards, Helliwell, & Blanchard, 2003). However, fluctuation in RVA parameters, especially peak viscosity, of the rice stored for 1-6 months, was reported (Pearce, Marks, & Meullenet, 2001;Soponronnarit, Chiawwet, Prachayawarakorn, Tungtrakul, & Taechapairoj, 2008;Wiset, Srzednicki, & Driscoll, 2003). Apart from storage time, the extent of these changes also depends on other factors, including amylose content of rice and storage temperature (Pearce et al, 2001;Sowbhagya & Bhattacharya, 2001;Zhou et al, 2003).…”

Cooked rice texture and rice flour pasting properties; impacted by rice temperature during milling

“…Therefore, factors affecting such measures are of great importance and thus studied extensively. These factors include planting and pre-harvest treatments, harvest moisture content, drying, storage and milling (Afzalinia et al 2004;Champagne et al 2004;Daniels et al 1998;Daniels et al 1996;Meullenet et al 1999;Pearce et al 2001;Ranalli et al 2003;Saleh and Meullenet 2007;Wang et al 2004).…”

The Instant Controlled Pressure Drop Process as a New Post-harvesting Treatment of Paddy Rice: Impacts on Drying Kinetics and End Product Attributes

“…In the case of paddy rice, hot air drying is a very important post-harvest stage which serves to decrease the initial moisture content, usually from 28% to 38% dry basis to a final moisture content of around 12% dry basis (Rice Workshop Quality 2003). Drying and storage conditions (temperature, air moisture) affect all functional and structural properties (Abud-Archila et al 2000;Pearce et al 2001;Cogburn 1985). The drying time remains relatively long (from 8 to 12 or even 24 h) and involves tempering periods.…”