Harnessing the nutritional benefits of Carissa edulis Vahl (Simple spined num-num) fruit harvested in Lowveld regions of South Africa

Abstract

The introduction of underutilised indigenous fruit crops to support mainstream crops is one of the promising strategies that can be employed to attain Sustainable Development Goals such as zero hunger. Among the crops of interest is Simple spined num-num (Carissa edulis Vahl), an indigenous fruit crop that is claimed to be nutrient-dense. However, the influence of various climatic conditions in the areas where it is prevalent is unknown. The study objective was to determine the effect of varying climatic and soil conditions on nutritional content and contribution of Simple spined num-num fruit concerning the recommended daily intake for communities of the Lowveld region. Freeze-dried samples of simple spined num-num fruit, harvested from diverse geographical regions (Bushbuckridge, Giyani, Tzaneen), were utilised for the analysis of biochemical constituents including vitamin C, total flavonoids, calcium, and zinc. Study results depicted that fruits harvested in Bushbuckridge were superior in vitamin C (36.9 mg/100 g DW), while those harvested in Giyani had the highest total flavonoid content (13.8 CE mg/100 g DW) compared to other regions. The Giyani region had superior calcium content (89.3 mg/100 g DW) compared to other regions. The highest zinc content (2.5 mg/100 g DW) was obtained from fruits harvested in the Tzaneen region. The nutritional and biochemical abundance of Simple spined num-num fruit underscores a compelling case for advancing it from local consumption to full-scale commercialisation, necessitating further research to optimise cultivation techniques, suitable climatic conditions, and extraction methods for commercial products.