Typically, banana trees are cut once the fruit has been harvested; however, other parts of the banana tree, particularly the leaves, might have other potential uses. Nevertheless, few studies have focused on banana leaves. This work aims to provide information about the effects of different drying temperatures on the antioxidant activity, total phenolic content and physical properties of banana leaves (Musa acuminata Colla (AAA Group)). Leaves were dried at different temperatures (40 °C, 50 °C or 60 °C) using a cabinet dryer with an airflow of 2 m/s. Dried and fresh leaves were analysed for their moisture content, water activity, pH, colour analysis and rehydration index. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Folin-Ciocalteau methods were used to determine the scavenging activity (IC50) and total phenolic content of the fresh and dried leaves extracts, respectively. The results reveal that the drying temperature significantly affects selected properties of banana leaves and 50 °C is proposed as the appropriate drying temperature.

Crescentia cujete has traditionally been used to treat various ailments. The present study attempted to determine the antioxidant activities of 100% ethanol, 50% ethanol and aqueous extracts of the leaves, bark and fruit of the herb. Additionally, the toxicity of the extracts was investigated in brine shrimp. The results showed that 100% ethanol leaf extract had the highest antioxidant activity with an IC 50 value of 261.97 ± 0.57 μg/mL according to the 2,2-diphenyl-1picrylhydrazil (DPPH) radical scavenging assay. Estimation of the total phenolic content (TPC) using the Folin-Ciocalteu reagent showed that the leaves extracted with 100% ethanol had the highest concentration of TPC compared to the extracts prepared with other solvents of all parts of the plant. Analysis of the minerals using inductively coupled plasma atomic emission spectroscopy (ICP-OES) showed that the parts of the plant primarily consist of high levels of phosphorus, magnesium and calcium. Titration analysis of vitamin C showed that the highest concentration of the vitamin is present in the bark. High performance liquid chromatography (HPLC) analysis of vitamin E indicated that the content is the highest in the fruit, and the content of vitamin A was the highest in the leaves. Brine shrimp lethality assay (BSLA) results showed that 50% ethanol extract of the leaves is the most toxic during a 24 h treatment. Thus, the leaves and bark exhibit excellent antioxidant effects and can be potentially developed as functional food ingredients. The findings of the present study suggest further research in cell lines and in vivo.

The challenge of high tropical temperature and chilling sensitive horticulture required an optimum postharvest handling to minimize the worldwide concern on the postharvest losses of tropical fruits and vegetables. To ensure the harvested produces achieves the consumer acceptability, the effect of temperature on the perishable produces along the integrated series of postharvest chain operations including harvesting, processing, storage and transportation must be crucially maintained. Even though the cooling process during the postharvest handling helps to reduce deterioration from high tropical temperature, the refrigeration storage temperature may also result in detrimental chilling injury. Quality of the produces reduced because of the development of symptoms include internal and external discoloration, abnormal fruit ripening, accelerated senescence, skin pitting, wilting, increase susceptibility to decay and loss of flavour. Optimum storage temperature for specific fruits and vegetables, temperature conditioning, intermittent warming technique, controlled atmosphere storage, chemical treatments and application of growth regulator can be applied either to retard the damaging symptoms or to increase the tolerance of the commodities towards chilling injury in order to extend fresh produces shelf life.