Evaluation of the influence of pH modification on food proteins struc-ture by FT-IR and AFM

Abstract

Objective: The aim of this study was to evaluate the influence of pH variation (3.6, 4.6 and 5.6) on morphometric parameters and the secondary structure of proteins (ovalbumin and gliadin). Design/methodology/approach: The arithmetic mean roughness (Ra) and agglomerate size (AS) of the proteins were analyzed by atomic force microscopy (AFM), while their secondary structure was analyzed by Fourier transform infrared spectroscopy (FT-IR), both at different pH. Subsequently, a correlation analysis of the morphometric changes of the proteins with their secondary structure was performed. Results: Highlighting that it was found that, protein agglomerate size is influenced by changes in β-sheets and turn conformations. Limitations on study/implications: Effect of pH variation (3.6, 4.6, and 5.6) on morphometric parameters and the secondary structure of proteins (ovalbumin and gliadin). Findings/conclusions: The novelty of this contribution consists in demonstrating that there is a close structure-functionality relationship between the morphometric parameters of proteins and their secondary structure, combining microscopy and spectroscopy techniques. This allows a clear and deep understanding of protein behavior to select the appropriate pH conditions to improve the properties of many foods.