Effect of Infrared Treatment on Chemical and Structural Quality of Soybean: Quantitative Three-Dimensional Characterization Using X-Ray Microtomography

Soybean is a source of high-quality vegetable protein and a suitable substitute for meat protein. However, several factors, including a lengthy cooking process, palatability issues, and digestion concerns, have limited their consumption. Several treatments have been suggested to overcome such issues, including infrared heating, which has many advantages over traditional roasting methods. In this study, the three-dimensional microstructure of soybeans with initial moisture contents (12, 16, 20, and 24% w.b.) and treated at different micronization durations (60, 90, and 120 s) at 180 degrees C were studied and related to quality parameters including water absorption and hardness of both non-cooked and cooked samples. The water absorption tests demonstrated no significant difference (p > 0.05) between the moisture absorbed for 60, 90, and 120 s micronization with initial moisture levels of 12, 16, and 24%. Yet all soybeans treated for 60 s exhibited significantly different results (p < 0.05) compared to raw counterparts. The highest hardness values were achieved after 60 s treatments on 24% moisturized seeds. As expected, the 20 min cooking time resulted in a considerable reduction in soybean hardness. The X-ray micro-computed tomography (micro-CT) was a powerful non-destructive tool to explore the microstructure of individual soybean seeds. Results of X-ray micro-CT have shown an increase in open porosity with increasing infrared treatment time. Overall, the qualitative and quantitative analysis provided in this study may serve as a basis for developing improved food processing techniques.