Pressure-induced changes in the structure of corn starches with different amylose content

Effects of Pressure, Temperature, Treatment Time, and Storage on Rheological, Textural, and Structural Properties of Heat-Induced Chickpea Gels

Pressure-induced gelatinization of chickpea flour (CF) was studied in combination with subsequent temperature-induced gelatinization. CF slurries (with 1:5 flour-to-water ratio) and CF in powder form were treated with high hydrostatic pressure (HHP), temperature (T), and treatment time (t) at three levels (200, 400, 600 MPa; 10, 25, 50 °C; 5, 15, 25 min). In order to investigate the effect of storage (S), half of the HHP-treated CF slurries were immediately analyzed for changes in oscillatory rheological properties under isothermal heating at 75 °C for 15 min followed by cooling to 25 °C. The other half of the HHP-treated CF slurries were refrigerated (at 4 °C) for one week and subsequently analyzed for changes in oscillatory properties under the same heating conditions as the unrefrigerated samples. HHP-treated CF in powder form was analyzed for changes in textural properties of heat-induced CF gels under isothermal heating at 90 °C for 5 min and subsequent cooling to 25 °C. Structural changes during gelatinization were investigated using microscopy. Pressure had a more significant effect on rheological and textural properties, followed by T and treatment t (in that order). Gel aging in HHP-treated CF slurries during storage was supported by rheological measurements.

Effects of High Hydrostatic Pressure Treated Mung Bean Starch on Characteristics of Batters and Crusts from Deep-Fried Pork Nuggets

Influences of mung bean starches treated with different high hydrostatic pressure (HHP) on the properties of batters and crusts from deep-fried pork nuggets were explored. HHP-treated starch increased water retention capacity of batter and consequently the batter pick-up. The increase in pressure at 150–450 MPa could facilitate hydration and swelling of starch granules during gelatinization. The crusts containing HHP-treated starches had higher moisture and less oil content, and the oil content was 15.82 g/100 g dry weight (DW) for 450 MPa treated starch, which was much lower than that of native starch (18.39 g/100 g DW) (p<0.05). Additionally, HHP-treated starches changed the crispness of crusts with increases in the slope and decrease in the shearing distance. Results indicated that mung bean starch treated with HHP in the range of 150–450 MPa could improve the quality of deep-fried battered food.

Characterization of acetylated corn starch prepared under ultrahigh pressure (UHP)

To investigate the impact of ultrahigh pressure (UHP) on the physicochemical properties of the UHP-assisted starch acetate, common corn starch was subjected to either conventional (0.1 MPa, 30 degrees C, 60 min) or UHP-assisted (400 MPa, 25 degrees C, 15 min) acetylation reactions at three levels (4, 8, or 12%) of acetic anhydride. Without significant changes in starch granule crystal structure, UHP-assisted reaction exhibited lower degree of substitution values than conventional reaction across reagent addition levels. An increase in reagent addition levels exhibited common trends in starch solubility/swelling power, gelatinization, and pasting properties for the conventional and UHP-assisted starch acetates relative to native starch. Within an equivalent derivatization level, however, the UHP-assisted (relative to conventional) starch acetates revealed restricted starch solubility/swelling power, reduced gelatinization temperatures, and lower pasting viscosities. Overall, this result suggested that UHP treatment in acetylation reaction might influence the physicochemical properties of starch acetate by facilitating the formation of lipid-complexed amylose or altering granular reaction patterns to acetic anhydride.