Enhancing shelf-life of dried goji berry: Effects of drying methods and packaging conditions on browning evolution

Preservation and shelf-life extension are of paramount importance for dried goji berry, especially those dehydrated using pulsed vacuum drying (PVD), which are generally applied for the high-quality dried products in the markets. This study compared the storage stability of dried goji berry dehydrated using PVD versus conventional hot wind drying (HWD), focusing on the complex interactions between packaging conditions and physicochemical compounds during accelerated storage. The results showed that PVD-dried goji berry exhibited higher browning degree (2.65 to 4.69) compared to HWD-dried berry (1.48-2.32). This difference was contributed to enzymatic and non-enzymatic precursors such as carotenoids, phenolics, reducing sugar, and intermediate products including 5-hydroxymethylfurfural, which also affected by the cuticular waxes leading to uneven and wrinkled appearance. Structural equation modeling and Pearson's analysis identified that Maillard reaction products as the primary factor of color deterioration in PVD-dried goji berry, with path coefficient of 0.460 and 0.241, and also depended on the light atmosphere. In contrast, the browning in HWD-dried goji berry was mainly due to the quinones accumulation with path coefficient of 0.343, associated with phenolics and intermediate compounds. In conclusion, the findings suggest that the selection of drying methods is crucial for determining appropriate storage conditions for dried goji berry, which provides scientific guidance for the selection of appropriate drying and storage methods to improve the product quality and stability in future efforts.