Ultra-fine Pulverization of Rice: Effects on Hydration Properties and Enzymatic Hydrolysis

Abstract

We studied the hydration properties and enzymatic hydrolysis of micro-sized rice flour obtained by dr y jet-pulverization to find new applications for the flour in the food industr y. Ultra-fine rice flour (both white and brown) with a mean size of <5 μm was far more dispersible than coarser flours (15-10 μm). Dispersibility increased with finer mean particle size and higher starch damage. The ultra-fine flour also had the highest solubility, swelling power, water absorption index, and glucose release. Dry jet-pulverization to <5 μm mean size and consequent starch damage to (>30%) decreased enthalpy and gave very different hydration properties and enzymatic hydrolysis than in coarser flours.

Innovative Milling Processes to Improve the Technological and Nutritional Quality of Parboiled Brown Rice Pasta from Contrasting Amylose Content Cultivars

“…In both cultivars, the C fraction showed a significantly higher amylose percentage than the F fraction (34.4% vs. 27.6% in cv Gladio and 27.0% vs. 22.2% in cv Ronaldo) (Figure 2B), as already observed for the TS. This result could be a consequence of the major structure breakage of starch granules occurring upon micronization mainly in the smallest mean size fraction (F), as also observed by Hossen et al [36].…”

Functional Properties of Submicron‐Scale Rice Flour Produced by Wet Media Grinding

“…Starch damage and digestibility showed relatively low correlations with mean size (R 2 = 0.70 and 0.77, respectively; Fig. WAI and starch damage were highly correlated (R 2 = 0.97), because starch damage induced higher water absorption (Hossen et al 2013). 4).…”

“…4). WAI and starch damage were highly correlated (R 2 = 0.97), because starch damage induced higher water absorption (Hossen et al 2013). These results show that the increase of digestibility cannot be explained by mean particle size alone, because other attributes were more highly correlated with digestibility; starch damage was influenced not only by particle size but also by milling method (Hossen et al 2011b), because greater starch damage does not always mean smaller particle size, and similar mean-sized particles obtained from different grinding methods may have different degrees of starch damage.…”

“…The micronization and hence both the reduction of particle size and increase of starch damage result in decreases in viscosity, gelatinization temperature, and gelatinization enthalpy and in increases in water solubility and digestibility (Han et al 2007;Kim et al 2011;Hossen et al 2011aHossen et al , 2011bHossen et al , 2013Hasjim et al 2012). The micronization and hence both the reduction of particle size and increase of starch damage result in decreases in viscosity, gelatinization temperature, and gelatinization enthalpy and in increases in water solubility and digestibility (Han et al 2007;Kim et al 2011;Hossen et al 2011aHossen et al , 2011bHossen et al , 2013Hasjim et al 2012).…”

“…documented. The micronization and hence both the reduction of particle size and increase of starch damage result in decreases in viscosity, gelatinization temperature, and gelatinization enthalpy and in increases in water solubility and digestibility (Han et al 2007;Kim et al 2011;Hossen et al 2011aHossen et al , 2011bHossen et al , 2013Hasjim et al 2012). The particle size heterogeneity influences the hydrolysis and hydration properties of rice flour, and further size reduction below a critical size (<80 µm fraction) strengthened effects on structural changes in grain components (de la Hera et al 2013).…”