Effects of different e-commerce packaging combined with blue light irradiation on the shelf quality of blueberries

This study aims to explore the effects of different e-commerce packaging with blue light irradiation on the postharvest quality of blueberries. Vaccinium corymbosum 'Bluecrop' blueberries were taken as the test materials. Five common e-commerce packaging treatments were compared after preservation, namely household plastic wrap (HPW), open preservation box (OPC), zippered preservation bag (WPF), window preservation study box (TPP), and sealed film preservation box (SFC), under 40 lx blue light (440-505 nm) irradiation for 12 days. The results showed that the SFC performed best in physical properties. There was a better barrier property from water vapor and moderate O₂/CO₂ gas under the LED blue light transmittance. A high humidity and mild modified atmosphere (MA) environment was formed for blueberries. Moderate CO₂ accumulation, far from detrimental levels, provided effective transmission of the blue light. Synergistic environmental stress was combined to regulate the postharvest physiology of blueberries. All packaging treatments delayed the deterioration of blueberry quality. Among them, the SFC group showed the most significant performance. The respiration rate and ethylene release of blueberries were 41.14% and 34.63% lower than the control group, respectively, thus delaying fruit aging. By the end of the shelf life (day 12), the SFC group exhibited higher fruit firmness. Meanwhile, the decay rate of the SFC group was only 42.82% that of the control group. In terms of active substances and antioxidant capacity, SFC packaging promoted the continuous accumulation of active substances, such as anthocyanins and flavonoids, in blueberry fruits, whereas the total phenols were maintained during storage, indicating a high content of bioactive components. Additionally, the DPPH free radical scavenging reached the peak in the middle and later stages after storage. The SFC treatment performed best in resisting postharvest senescence due to its high antioxidant activity. Meanwhile, the SFC packaging can be expected to reduce the loss of internal free water in fruits, particularly for the high proportion of bound water and cell structure integrity. Magnetic resonance imaging showed that the water distribution state of blueberries in the SFC group after 12 days on the shelf was the closest to that of fresh samples, indicating its excellent water retention. Sealed-film preservation box (SFC) with LED blue light irradiation can also provide a favorable micro-environment for the optimal physical barrier and light transmission, thereby encompassing humidity control, modified atmosphere, and light stress. This finding can offer a strong reference for the high storage quality and physiological activity of postharvest blueberries.