초임계 이산화탄소 처리한 밀가루의 이화학적 특성과 품질 평가

Abstract

Physicochemical Properties and Qualities Evaluation of Wheat Flour by Supercritical Carbon Dioxide Treatment Hee Moon Kang

Department of Food Science and Technology, The Graduate School, Pukyong National University

Abstract

Carbon dioxide in supercritical state has the unique ability to dissolve the chemical components that has been used for applications in refinement, extraction, separation, recrystallization of various materials based on its solubilizing effect. Although these applications have been used in food, chemicals, pharmaceuticals, materials, environment and energy industries to improve the product quality and efficiency, and continued to expand its range of applications, little information on the wheat flour treated by the supercritical carbon dioxide exist in the literature. Therefore, the influence of the supercritical carbon dioxide on wheat flour quality attributes was investigated by use of the change in pressure of supercritical carbon dioxide and 70% ethanol for the commercially milled U.S. Hard Red Spring wheat.

Flour moisture and fat content were decreased due to the solubility of the supercritical carbon dioxide, and crude protein concentration was increased by reduction of other components. The relative changes in protein content were shown by increased solubility of the solution, while change in the percentage content of gluten-forming proteins was not affected. Damage starch content was decreased by a function of stabilization caused by changes in pressure, and ash content was not affected. Liquefied starch Falling Number (FN) value was decreased due to the pressure treatment.

Water absorption on Farinogram and SRC value were increased by the impact of the reduction of moisture and fat content, and dough development time and stability were also increased due to the increased flour particle size and water absorption rate. The elasticity and area on extensogram were strengthened by increasing SRC value. RVA peak viscosity and setback were decreased due to the liquefied starch caused by pressure. Reduced sedimentation test values were contributed by the protein denaturation. Flour color changes in whiteness and yellowness were also affected by the supercritical carbon dioxide extraction. Increase in the bulk density and decrease in the angle of repose were influenced by the flour cohesion property caused by increase in particle size and reduction in the other flour components.

Flour particle size was increased by over pressure at 200 bar, and flour brightness was not significantly changed due to the combination effect of flour particle size and yellowness. Bread volume and hardness in addition to cookie hardness and thickness were increased as the water absorption was increased. A reduction in fat acidity and acid value was affected by a decrease in fatty acids, and the reduction of microbial toxins and fungi, volatiles were also removed or reduced.

Supercritical carbon dioxide processing and measurement were highly correlated with 75% of the flour quality parameters (r ≥ 0.5). A 66.7% of them showed the positive (+) correlation and 33.3% were the negative (-) correlation. Significant correlations (0.05 ≥ p) with the flour quality variables included the flour brightness, yellowness, bulk density, crude protein, and crude lipid content. Crude lipid and protein contents showed the highest correlation. Variation of changes in supercritical carbon dioxide pressure treatment was 41.1% (CV ≤ 5) in the flour quality variables which appeared to be least variation, 33.9% had the variation (5 ≤ CV ≤ 14), and 25% showed the largest variation (CV ≥ 14). Quality variables that did not have variations of the supercritical carbon dioxide treatment were not affected by the change in supercritical carbon dioxide pressure treatment.

In this study, supercritical carbon dioxide treatment affected the changes in the flour composition, flour plasticity, physical properties for improving the flour storage and transport efficiency, flour color, baking quality, and flour safety by removing the inhibiting factors. Supercritical carbon dioxide technology appeared to be highly correlated with flour quality characteristics and could be used for improving the wheat flour quality as an effective means.