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

Authors: RAHMANPOUR, MOZHDEH - University Of Georgia; MOZAFFAR, FATEMEH - University Of Georgia; PAGAN, MICHAEL - University Of Georgia; MORKOS, BESHOY - University Of Georgia

Submitted to: Journal of Food and Bioproducts Processing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2025
Publication Date: 8/21/2025
Citation: Rahmanpour, M., Mozaffar, F., Pagan, M., Morkos, B. 2025. Characterizing moisture content variation in pecan kernels under cold and hot water soaking treatments. Journal of Food and Bioproducts Processing. 154:33-41. https://doi.org/10.1016/j.fbp.2025.08.011.
DOI: https://doi.org/10.1016/j.fbp.2025.08.011

Interpretive Summary: This study addresses the significant loss—up to 50%—of pecan kernels during mechanical processing due to damage, highlighting the importance of proper moisturization to improve efficiency and reduce waste. Researchers investigated two water conditioning methods—cold and hot soaking—to optimize moisture content in pecans before shelling. Cold soaking at 21°C for 5 to 35 hours enabled gradual, uniform moisture absorption, while hot soaking at 82–93°C for 5 to 20 minutes offered quicker but less consistent results. Statistical analyses, including regression and ANOVA, were used to identify the most effective conditions and key factors influencing moisture levels. Higher temperatures in the hot water method were found to significantly impact moisture uptake. The study provides practical recommendations for industry adoption to enhance quality and reduce processing costs. Future research will test these findings with direct measurements and explore hybrid techniques for even better results.

Technical 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 hours, while hot water soaking utilized temperatures between 82°C and 93°C for 5 to 20 minutes. 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. Future work will validate these findings using primary measurement methods and 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.