Sathish Kumar M HICAR-National Dairy Research Institute, India
Title: Dipeptidyl peptidase-IV inhibitory potential of alpha-lactalbumin extracted from milk of Gir cows
Recent advances in food and nutrition sciences have been exploring milk peptides for their nutraceutical and therapeutic benefits. In this study, an attempt was made to assess the hypoglycemic effect of α-lactalbumin (α-LA) isolated from milk of Gir cows. The enzymatic hydrolysis of extracted α-LA was carried out using Flavourzyme, pepsin, trypsin and proteinase-k individually at 1%, 2% and 4% enzyme-substrate (E-S) ratio for a period of 2 - 12 h. Pepsin-treated hydrolysates showed maximum DPP-IV inhibition of 87.81±0.84% (IC50 =0.78 mg/mL). The permeate of 3 kDa, which exhibited 84.47±2.29% DPP-IV inhibition was fractionated through RP-HPLC. All fractions were analysed for DPP-IV inhibition activity. One novel peptide was identified through LC-MS/MS, which showed adequate DPP-IV inhibition (IC50 =4.93 mM). The α-LA hydrolysates which showed highest DPP-IV inhibition was encapsulated in double emulsion (DE) matrix. The optimized DE had 17.33 ± 0.97 µm mean diameter, -35.43 ± 1.85 mV zeta potential and 93.00 ± 0.90% encapsulation efficiency with 5% loading of DPP-IV inhibitory peptides in the inner phase. Encapsulated peptides showed ~4 times better DPP-IV inhibition activity than non-encapsulated after simulated digestion. The oral administration of the non-encapsulated hydrolysate (NEH), freeze-dried encapsulated hydrolysate (FDEH) and emulsified encapsulated hydrolysate (EEH) at a dose of 300 mg/kg body weight was evaluated in nicotinamide-streptozotocin induced type-2 diabetic experimental rats in a study of 30 days. Rats in diabetic control group showed an increase in blood glucose level, liver function enzymes and decrease in GLP-1, insulin, antioxidative enzymes. Administration of hydrolysates reversed the parameters by lowering blood glucose level and increasing GLP-1 and insulin levels in plasma. Blood lipid profile, liver enzymes ALT, AST and AP, catalase and SOD activity were also normalized and better managed in experimental diabetic rats.
Sathish Kumar M H presently working as Senior Scientist at ICAR-NDRI, Benagluru. He worked in Amul, Perfetti Van Melle Pvt. Ltd. and Cargill India Pvt. Ltd., at various capacities before joining ICAR as scientist in 2010. He had received merit award for his PhD work from NDRI. He has good experience of dairy and fruit beverages formulation. Presently his work focused on mining of anti-diabetic peptides from milk. He has over 30 publications that have cited over 380. He bagged two prestigious projects from ICAR-National agricultural science fund besides DST and MoFPI projects.