Comparison of five chickpea varieties, optimization of hydrolysates production and evaluation of biomarkers for type 2 diabetes

Abstract

The objective was to compare five varieties of chickpea (Cicer arietinum), sequence the peptides obtained with pepsin-pancreatin digestion, and evaluate their potential as modulators of biochemical markers for type-2 diabetes. In addition, to produce a functional ingredient, by the optimization in the production of hydrolysates using bromelain. Proteins of ground raw, precooked and cooked chickpea, were extracted, isolated, and characterized using SDS-PAGE gel electrophoresis. Hydrolysates were obtained by simulated digestion with pepsin-pancreatin, and resulting peptides were sequenced with LC-MSMS. Response surface methodology was used to optimize the production of hydrolysates with dipeptidyl peptidase IV (DPPIV) inhibition using bromelain. Protein profiles showed fractions of convicilin (>70 kDa), 7S vicilin (43-53 kDa), 11S legumin (35 kDa) and lectins (30-32 kDa) in raw varieties. Albumin fractions 2S (20-26 kDa) were still present in most varieties after 2 h of heat treatment. DPPIV IC₅₀ values from digestive enzymes were better (0.17-2.21 mg/mL) in raw chickpea than in cooked chickpea. α-Glucosidase inhibition at 10 mg protein/mL was highest (32-66%) in precooked chickpea hydrolysates. Hydrolysis with bromelain showed a DPPIV inhibition of 94% for Sierra variety cooked for 15 min with 1:10 E/S ratio and hydrolysis time of 60 min. Peptides with DPPIV inhibition were present from albumin fractions (EVLSEVSF) with 908.44 Da and high hydrophobicity; and from legumin (VVFW, FDLPAL) with 549.29 and 674.36 Da, respectively. In conclusion, high DDPIV inhibition can be obtained from chickpea bromelain hydrolysates, with potential as ingredients in different food applications.

Keywords: Bioactive peptides chickpea; Cicer arietinum; DPPIV inhibitor enzymatic hydrolysis; α-Amylase; α-Glucosidase.