Modeling of Water Absorption of Pinto Beans During Blanching and Soaking

Blanching and soaking are essential thermal processing steps in the process of precooked pinto beans. Appropriate blanching and soaking conditions could reduce antinutritional factors, such as trypsin inhibitors, improve the quality of finished products, and reduce processing time and solid losses. The characteristics of water absorption (hydration ratio and moisture content) and solid losses of pinto beans were measured at various temperatures (30 to 100℃) and time periods (5 min to 24 h). It was found that the hydration ratio, moisture content, and solid loss increased with the increased temperature and time. But the rate of water absorption decreased with the increase of time. To obtain high quality product with minimum processing time and solid loss, variable temperature for blanching and soaking is normally used. Models for predicting the hydration ratio and moisture content were developed and validated under variable blanching and soaking temperatures and time periods.