Influence of ohmic heating on lentil protein structure and protein-pectin interactions

Abstract

Proteins are essential for creating structured food systems due to their interactions with other molecules, but their structure is highly affected by temperature. This study aimed to evaluate the effects of different thermal processes (conventional and ohmic heating) on lentil protein structure and its interactions with pectin. The results showed that thermal processes can modify lentil protein structure, with the extent of modifications depending on the treatment temperature, electric field strength, and pH of the protein fraction extraction. Lentil protein extracted at pH9 was more stable to temperature variation under ohmic heating. When a low electric field strength (5V/cm) was applied, there was an increase in the hydrophobic surface and accessibility of sulfhydryl groups. In contrast, lentil protein extracted at pH7 was highly affected by all thermal treatments. Although structural changes were observed in some protein features, no influence was identified regarding lentil protein-pectin interactions. In conclusion, ohmic heating treatment has the potential to modify lentil protein structure, but the outcomes may depend on the extraction method used, which can dictate different structural arrangements of the native protein fraction. Industrial relevance The development of plant-based products have increased in the last years and other proteins, instead of soybean and pea, are required to meet new consumers' needs. Lentil protein is a non-soy, gluten free, and plant-based protein that could be an alternative to the plant-based market. These proteins can act as texturizing, emulsifying, foaming, and gelling agents but their suitable performance is dependent on protein structure. Thermal processes are a necessary component of food production, requiring careful control of the conditions involved as heat can drastically modify the structure of proteins, Therefore, in this study, the effects of two thermal processes (conventional and ohmic heating) on lentil protein structure and its interactions with pectin were evaluated. These findings may provide insights for developing more appropriate processes to preserve protein structure during food processing at industry.