Structure, physicochemical properties, and in vitro starch digestibility of yellow pea flour modified with different organic acids
Citation
Waduge, R.N., Warkentin, T.D., Donner, E., Cao, R., Ramdath, D.D., Liu, Q. (2017). Structure, physicochemical properties, and in vitro starch digestibility of yellow pea flour modified with different organic acids. Cereal Chemistry, [online] 94(1), 142-150. http://dx.doi.org/10.1094/CCHEM-03-16-0068-FI
Plain language summary
Enhanced slowly digestible starch and resistant starch in the starchy-food products can slow the absorption of glucose into the bloodstream to help stabilize blood sugar levels of human being. The objective of this research is to utilize a suitable physicochemical modification technology to develop pea flour with enhanced slowly digestible starch (SDS) and resistant starch (RS) contents that can be used as a food ingredient. The flour obtained from the whole seed was used for the modification as an attempt to preserve some of the nutritional quality originates from non-starch materials. In this study, pea flour, germinated pea flour, and extracted pea starch are modified with citric acid under different treatment conditions and compare the effect of modification on their SDS and RS contents. The structure and functionality of starch extracted from modified flour and products were investigated to understand the effect of modification on their behavior. By using pea flour with enhanced SDS and RS contents, which was obtained by above modifications, as an ingredient, we expect to produce food products with improved starch digestibility profile for human nutritional and health benefits.
Abstract
The objective of this study was to produce a pea flour ingredient with higher slowly digestible (SDS) and resistant (RS) starch fractions for functional food applications. Heat-moisture treated flour (HMTF) in the presence of citric, gallic, or vanillic acids and esterified flour (EF) with citric acid were prepared and analyzed for structure and functionality using in vitro starch digestibility, differential scanning calorimetry, Rapid Visco Analyzer, swelling factor (SF), amylose leaching (AML), optical microscopy, and Fourier transform infrared (FT-IR) spectroscopy. Significant (P < 0.05) increases in SDS and RS content of HMTF and EF were observed. Whereas the granule integrity and the birefringence were not affected by modification, the degree of crystalline order, which was determined by FT-IR 1,047/1,022 cm-1 peak ratio, was decreased. Gelatinization enthalpies of modified flour were lower than that of native flour, whereas the gelatinization endotherms of HMTF were shifted to higher temperatures and those of EF to lower temperatures. Pasting properties were also affected greatly by both treatments. HMTF demonstrated reduced SF and AML, whereas EF had reduced SF and increased AML. Further, the extent of changes in the structure and functionality of HMTF depended on the type of acid utilized. Overall, heat-moisture treatment with an organic acid and esterification were effective modifications to produce a pea flour ingredient with enhanced SDS and RS content.