Changes in quality of low-moisture conditioned pine nut (Pinus gerardiana) under near freezing temperature storage

Abstract

Changes in quality of low-moisture conditioned pine nuts (Pinus gerardiana) under near freezing temperature storage were investigated. Nuts were adjusted to different moisture content (17.3% ± 0.42, 15.1% ± 0.26, and 13.3% ± 0.24) with 35°C, 20%RH, sealed in air-tight jars and stored at −3 and −1°C for 12 months. In general, free fatty acid content and peroxide value of the nuts increased, while sensory quality decreased during the storage. Low-moisture nuts had lower respiration, free fatty acid content, and peroxide value. Nuts stored at −3°C had less visible mold infection and browning percentage than at −1°C. Low-moisture treatment exerted a slight negative effect on texture, but had significant preservative effects on color, odor, and taste during storage. Overall, integration of low-moisture conditioning and near freezing temperature storage can be a promising non-chemical way for maintaining the postharvest quality and extending shelf-life of pine nuts.