Nutritional Composition of New Zealand-Grown Kiwano Fruit: A Comprehensive Analysis

Kiwano or African horned cucumber (Cucumis metuliferus) is an exotic fruit native to Africa and widely grown and exported in New Zealand. However, data on its nutritional profile and chemical composition are scarce despite its global distribution. In addition, Kiwano is relatively unknown in the domestic markets of New Zealand, emphasising the need for this research to raise awareness of its nutritional value, health benefits, and potential for food product development. Analysing different parts of Kiwano is essential for identifying geographical variations in nutrient composition, ensuring a comprehensive understanding of its nutritional potential and targeted food applications. In this study, quantitative analysis of the macro- and micro-nutrients of various fruit parts, such as pulp, seeds, peel, and leaves, was conducted. Our results showed that Kiwano seeds were rich in fat (35.75%), protein (34.02%), and fibre (22.63%), whereas the pulp was high in moisture (13.63%) and carbohydrates (76.54%), and the peel was high in ash (17.33%). The difference in protein content in the different parts of the fruit led to further investigation into the amino acid profile in which histidine, methionine, isoleucine, leucine, and phenylalanine were higher in the leaves and seeds whereas threonine, lysine, and tryptophan were only abundant in seeds. Kiwano leaves showed significantly (P < 0.05) higher levels of vitamins B5, C, D2, E, and K1 while beta-carotene content was high in the leaves and peel and levels of vitamin B1 were high in the seeds and peel. Overall, NZ-grown Kiwano hashigher levels of fat, protein, fibre, and key nutrients than reports from Nigeria and other regions, highlighting its potential for functional food development and the need for further regional comparisons.