Physicochemical, functional and rheological properties of grass pea (Lathyrus sativus L.) flour as influenced by particle size

Different properties of grass pea (Lathyrus sativus L.) flour passed through 60, 72, 85, 100, 150 and 200 mesh sieves and in the size range of 249-74 μm were studied. The protein content reduced while fat content improved significantly with diminution in particle size. Flowability, capacities to absorb water and form foam as well as stability of foam decreased while increase in swelling capacity, swelling index, oil absorption capacity was observed with decrease in flour particle size. Bimodal curve patterns were obtained for coarse flour samples of 249 μm and 211 μm using light scattering analysis. Scanning electron microscopy analysis revealed that starch granules were of variable shape embedded in protein and fibre matrix. The flour with fine particle size exhibited greater values for peak, final, break down and set back viscosities and the dough from fine particles showed highest values for storage modulus (G′), loss modulus (G″),|G(∗)| and |η(∗)|.