Impact of biodegradable film packaging and storage conditions on health-promoting compounds and microbial diversity of African nightshade (<i>Solanum nigrum</i>) leaves

Abstract The effect of biodegradable film packaging and storage conditions on health-promoting secondary plant metabolite contents and microbiological quality of African nightshade leaves was investigated. African nightshade cultivated under greenhouse conditions was harvested 11 weeks after sowing, followed by storage in biopacked and unpacked conditions at 6 °C and 20 °C for 7 days. Utilisation of biopacks significantly reduced fresh weight losses (83%–96% at 6 °C; 82%–96% at 20 °C) compared to unpacked samples (65%–71% at 6 °C; 39%–49% at 20 °C), with significantly higher losses in samples at 20 °C. Leaf colour attributes were better retained in biopacked than unpacked samples, with the exception of biopacked samples at 20 °C (day 7), which showed increased leaf yellowing. Except the chlorophyll content; phenolic acids (92%), flavonoids (82%), and carotenoid (99%) contents were retained during storage at both temperatures irrespective of the packaging conditions. In contrast, the ascorbic acid content declined by at least 36% in both biopacked and unpacked samples during storage. With respect to food safety aspects, the use of biopacks did not reduce microbial counts, except for the total bacterial (2.96 log CFU g−1) and mould (3.09 log CFU g−1) counts at 6 °C storage.