Comparison of Morphological and Physicochemical Properties of a Floury Rice Variety upon Pre-Harvest Sprouting

Abstract

Pre-harvest sprouting (PHS) severely reduces rice grain yield, significantly affects grain quality, and leads to substantial economic loss. In this study, we aimed to characterize the physicochemical properties and processing quality of the Garumi 2 flour rice variety under PHS conditions and compare them with those of the Seolgaeng, Hangaru, Shingil, and Ilpum rice varieties and the Keumkang wheat variety. Analysis of the molecular structure of starch revealed uniform starch granules, increased proportions of short-chain amylopectin in DP 6–12 (51.0–55.3%), and enhanced crystallinity (30.7–35.7%) in rice varieties for flour compared with the Ilpum cooking rice variety. PHS significantly altered the starch structure and gelatinization properties of Garumi 2. It also caused surface pitting and roughness in Garumi 2 starch granules and decreased their crystallinity. Collectively, the findings of this study provide important novel insights into the effects of PHS on the physicochemical properties of Garumi 2 floury rice for flour.

Nitrogen fertilization levels influence the physicochemical properties of floury rice varieties

“…The granule size distribution of the flour from each experimental variety was measured using a laser diffraction particle size analyzer (Mastersizer 2000;Malvern Panalytical Ltd.). The flour samples were immersed in ethyl alcohol and measured as previously described (Han et al, 2021).…”

“…Finally, 4-ml glucose oxidase/peroxidase solution was added before a 20-min chromogenic reaction, and the absorbance was calculated at 510 nm. The damaged starch percentage was calculated as previously described (Han et al, 2021).…”

“…Amylose and protein contents of the endosperm of milled rice samples were calculated using a Cervitec 1625 Grain Inspector (Foss Analytical) as previously described (Han et al, 2021).…”

“…The gelatinization properties of starch were evaluated using Differential scanning calorimetry (DSC) as previously described (Han et al, 2021). Briefly, 3.0 mg rice flour and deionized water (1:2, v/v) were poured into an aluminum pan using a microsyringe.…”

“…The chain-length distribution of amylopectin was analyzed using a high performance anion-exchange chromatography system equipped with pulsed amperometric detection (HPAEC-PAD) according to a previously described method (Jane et al, 1999), with some modifications (Wang & Wang, 2000). The HPAEC system (Dionex DX500; Dionex, Sunnyvale, CA, USA) consisted of a GP50 gradient pump, an LC20-1 chromatography organizer, an ED40 electrochemical detector, a CarboPac PA-1 guard column (4 × 50 mm), a CarboPac PA-1 analytical column (4 × 250 mm), and an AS40 automated sampler (Han et al, 2021).…”