South African Indigenous Kei Apples (Dovyalis afra)

Despite the global availability of approximately 7,000 cultivated edible plant species, the food system heavily relies on six crop species, which account for 56% of global primary crop production. Wild edible plants, such as the Kei apple (Dovyalis afra), offer nutritional and economic potential, particularly for small-scale farmers. Indigenous to southern Africa, Kei apples are drought-resistant, nutrient-rich, and traditionally used in jams and jellies. However, their short shelf life and limited research hinder broader commercial utilization. This study evaluates Kei apples’ suitability for jam production by analyzing physicochemical properties (pH, °Brix, acidity, and pectin) at different ripening stages (on-tree vs. off-tree) and assessing consumer preferences through sensory evaluation. Fruits ripened on-tree and off-tree were divided into four ripeness stages (wholly green to wholly yellow). Laboratory analysis revealed minor differences in pH and moisture, but on-tree ripened fruits had higher °Brix and acidity, while pectin decreased with ripeness. A trained panel identified fifteen sensory descriptors, noting fruity (apricot-like), sweet-medicinal, and savory aromas, with texture variations attributed to pectin distribution. Consumer testing (n = 369) indicated overall acceptability, though preferences varied: jams from intermediate ripeness (yellow with some green) were most favored (60.4% likely to purchase), while extreme ripeness stages (wholly green/yellow) elicited polarized responses. The study confirms the viability of Kei apples for jam production, with high pectin content compensating for acidity. However, optimizing ripeness and processing is essential for market readiness. Further research should explore genetic variability, off-tree ripening protocols, and recipe refinement to enhance commercial potential, support small-scale farmers, and diversify food systems.