Effect of pulsed ultrasound, a green food processing technique, on the secondary structure and in-vitro digestibility of almond milk protein
Sai Kranthi Vang, Jin Wang, Valérie Orsat, Vijaya Raghavan
Food Research International
In recent years, almond has been considered as one of the most common alternative plant-based protein sources due to its nutritional attributes and health benefits. However, almond protein has a lower digestibility compared with the animal protein. The objective of this study is to investigate the impact of pulsed high-intensity ultrasound on the secondary structure of the almond protein. The changes in the in-vitro protein digestibility (IVPD %) are also evaluated to investigate the relationship between the structure and digestibility of the almond protein. The secondary structures were analyzed using Fourier-transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectroscopy. FT-IR analysis showed a slight relocation in the ordered and unordered structures in the ultrasonicated almond protein compared to the control. CD spectroscopy revealed that ultrasound resulted in the restructuring of α-helices into β-sheets. However, upon treating the almond protein for 16 min, a slight recovery in α-helices was observed. Moisture content was found to affect the secondary structure orientations of almond protein significantly. Although the IVPD% change was not statistically significant, it was found to be increasing slightly with processing duration and was dependent on protein secondary structure.
Circular dichroism, Secondary structure, Chemical stability, Food science, Biochemistry