Comparative Study of the Effects of Processing on the Nutritional, Physicochemical and Functional Properties of Lentil

Abstract

The effects of processing (dry-milling, cooking, isoelectric precipitation) on the physicochemical, functional and nutritional properties of lentil were evaluated. Protein, moisture, lipid and ash contents of raw lentil flour (RLF), cooked lentil flour (CLF) and lentil protein isolate (LPI) ranged between 29.2 and 90.6%; 0.5 and 6.7%; 0.1 and 0.7%; and 2.4 and 3.4%, respectively. LPI contained smaller particles with narrower size distribution than CLF or RLF. RLF contained less lysine but had more determined sulfur-containing amino acids than the CLF. LPI and CLF, respectively, showed the highest and lowest solubility between pH 1 and 12. Water holding and fat absorption capacities were highest for LPI followed by CLF and RLF. Circular dichroism and FTIR spectroscopy showed minimal secondary structural changes in RLF and LPI compared with CLF. Anti-nutritional factors content and thermal properties revealed distinct variations between the two flours and protein isolate. Processing of lentils could be explored to modify its functionality for various food applications. Practical Applications This article presents simple processing methods (dry-milling, cooking and isoelectric precipitation) to modify and obtain value-added lentil products with improved physicochemical, functional and nutritional characteristics. Such processing approaches could markedly influence the value of lentil, diversify it use, and help to improve the competitiveness of the pulse sector. Research Highlights Milling, cooking and protein extraction modified the properties of lentil The protein-rich lentil isolate had low phytic acid and trypsin inhibitor content Protein solubility, water holding and fat absorption were improved in the isolate Amino acid content and quality of protein were highest in the protein isolate