Potential of whey protein isolate-lactose conjugates in the in-vitro infant digestion

Sabari S., . and Julmohammad N., . and Matanjun P., . and Ab. Wahab N., . (2022) Potential of whey protein isolate-lactose conjugates in the in-vitro infant digestion. Food Research (Malaysia), 6 (S1). pp. 53-66. ISSN 2550-2166

Protein base modification is a notable potential method to alter the molecular structure and physicochemical and functional properties of the protein, thus affecting protein digestibility. This study investigated the protein digestibility of whey protein isolate– lactose (WPI-Lac) conjugates using an in-vitro infant gastric digestion static model. WPI was conjugated with lactose by dry Maillard reaction under optimised conditions. The following conditions were studied, WPI-Lac heated at 40°C, water activity aw = 0.80 and incubation time of 0, 1, 3, 5 and 7 days. Based on the brown colour and the conjugation rates in ortho-phthaldehyde analysis, the incubation time of day 3 of conjugation promises the extent of conjugation and prevents the formation of advanced Maillard reaction products (MRPs). Functional properties of glycated protein were found to significantly higher (p<0.05) in antioxidant activity and solubility compared with native WPI. In addition, Fourier Transform Infrared (FTIR) analysis indicated that the WPI was modified by dry MR with lactose. WPI-Lac day 3 was evaluated using the in-vitro gastric infant digestion model which undergo simulated gastric infant condition at pH 3 with 19 μL of 0.625mg/mL of pepsin. Sodium dodecyl sulfate acrylamide gel electrophoresis (SDS- PAGE) analysis of digesta revealed that MRPs increased susceptibility to be hydrolysed by pepsin. The digestion product affirms dry MR conjugation can potentially improve WPI digestibility. Herein, this study of WPI-Lac conjugates contributes to an understanding of how protein–disaccharide glycates affect in-vitro infant gastric digestion.

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Abstract

Protein base modification is a notable potential method to alter the molecular structure and physicochemical and functional properties of the protein, thus affecting protein digestibility. This study investigated the protein digestibility of whey protein isolate– lactose (WPI-Lac) conjugates using an in-vitro infant gastric digestion static model. WPI was conjugated with lactose by dry Maillard reaction under optimised conditions. The following conditions were studied, WPI-Lac heated at 40°C, water activity aw = 0.80 and incubation time of 0, 1, 3, 5 and 7 days. Based on the brown colour and the conjugation rates in ortho-phthaldehyde analysis, the incubation time of day 3 of conjugation promises the extent of conjugation and prevents the formation of advanced Maillard reaction products (MRPs). Functional properties of glycated protein were found to significantly higher (p<0.05) in antioxidant activity and solubility compared with native WPI. In addition, Fourier Transform Infrared (FTIR) analysis indicated that the WPI was modified by dry MR with lactose. WPI-Lac day 3 was evaluated using the in-vitro gastric infant digestion model which undergo simulated gastric infant condition at pH 3 with 19 μL of 0.625mg/mL of pepsin. Sodium dodecyl sulfate acrylamide gel electrophoresis (SDS- PAGE) analysis of digesta revealed that MRPs increased susceptibility to be hydrolysed by pepsin. The digestion product affirms dry MR conjugation can potentially improve WPI digestibility. Herein, this study of WPI-Lac conjugates contributes to an understanding of how protein–disaccharide glycates affect in-vitro infant gastric digestion.

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Item Type:	Article
Additional Information:	10th Kuala Lumpur International Agricultural, Forestry and Plantation Conference 2021
AGROVOC Term:	whey protein
AGROVOC Term:	digestible protein
AGROVOC Term:	Maillard reaction
AGROVOC Term:	lactose
AGROVOC Term:	solubility
AGROVOC Term:	in vitro digestibility
AGROVOC Term:	antioxidants
AGROVOC Term:	human health
Geographical Term:	Malaysia
Depositing User:	Mr. Khoirul Asrimi Md Nor
Date Deposited:	04 Mar 2026 03:14
Last Modified:	04 Mar 2026 03:14
URI:	http://webagris.upm.edu.my/id/eprint/3521

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