Characterizing moisture content variation in pecan kernels under cold and hot water soaking treatments

Abstract

Each year, about 15 million pounds of pecan kernels are damaged during mechanical processing, reducing quality and yield by 30–50 %. Moisturization, an essential step in pecan processing, enhances cracking and shelling efficiency while minimizing waste. This process affects the mechanical properties of pecans, such as firmness and flexibility, ensuring kernels remain intact during cracking. This study investigates the effects of cold and hot bath conditioning methods on pecan moisture content, focusing on key variables like soaking time and water temperature. Cold water soaking was conducted at ambient room temperature (21°C) for durations ranging from 5 to 35 h, while hot water soaking utilized temperatures between 82°C and 93°C for 5–20 min. Statistical analyses, including regression models and ANOVA tests, were employed to develop predictive insights for achieving optimal moisture content. Regression analyses revealed distinct trends: cold water treatments allow uniform moisture absorption over extended durations, whereas hot water treatments achieve rapid absorption but with greater variability. Statistical models and ANOVA tests further identified key parameters and interactions influencing moisture outcomes, including the significant role of higher temperatures in the hot water method. These findings offer actionable recommendations for improving pecan processing efficiency, reducing costs, and enhancing product quality. The predictive moisture models presented in this study have not yet been validated against primary measurement techniques such as the oven-drying method. As such, the prediction error and deviation from standard reference values remain unquantified and are an important focus for future research. Future work will explore hybrid approaches combining hot and cold-water treatments. By optimizing moisture conditioning, this study contributes to reducing waste, aligning industry practices with sustainability goals, and meeting the growing demand for high-quality pecans in the global market.