How to keep your leaves fresh

Ever tossed slimy spinach? Then you already know why the battle to preserve African nightshade leaves in sub-Saharan Africa matters – because no one likes perfectly good food going to waste, and this study offers a surprisingly green solution. African indigenous vegetables (AIVs) like African nightshade are crucial for nutrition and income in sub-Saharan Africa. However, their high perishability leads to significant postharvest losses. The Urban Plant Ecology Group (Christian Ulrichs) investigated biodegradable film packaging's effectiveness in preserving the quality and safety of African nightshade leaves. They compared African nightshade leaves stored in biodegradable film packs to unpacked leaves at 6°C and 20°C for seven days. The packaging reduced weight loss and better retained leaf color compared to unpacked samples. It also helped maintain health-promoting compounds. Microbial counts were reduced at 6°C but not at 20°C. Therefore, biodegradable packaging shows promise for extending the shelf life and preserving the quality of African nightshade leaves, potentially reducing food waste and improving nutritional outcomes. If you want to know more about their win-win-win-win discovery, read the full article here.

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. Utilization 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 the total bacterial (2.96 log CFU g-1) and mould (3.09 log CFU g-1) counts at 6 °C storage.