Nutritional and anti-nutritional composition of Ziziphus spaina-Christi fruits grown in different agroforestry landscapes in Ethiopia

Abstract

Over one billion people globally rely on fruit trees for livelihood, including Ziziphus spina-christi , a less exploited but resilient species with dietary and economic potential. This study analyzes its fruit composition by land uses (home gardens, farmlands, roadsides), maturity stages (green, red, yellow), and seasons to guide domestication, conservation, and utilization possibilities for enhanced food security and livelihoods. Nutritional and anti-nutritional content of Z. spina-christi fruits was determined at various maturity stages (green, yellow, red) and land-use types in Ethiopia. Proximate analysis revealed significant ontogenetic variations, with protein content declining significantly (32.4%, p < 0.001) during ripening, most notably between the green-to-yellow stages. Phytate content had a rising trend (0.19%, p < 0.01), while tannin content remained unchanged (3.090–3.143%, p = 0.63). Moisture content had a unimodal pattern, rising during the yellow stage (1.985 ± 0.108%) before declining in red fruit, and was significantly influenced by land use, with home garden fruits having the greatest ash content ( p < 0.05), most likely due to higher soil fertility. Correlation analysis indicated negative correlations between protein and maturity ( r = – 0.386, p < 0.05) and between tannins and phytates ( r = – 0.406, p < 0.05), pointing to metabolic trade-offs during fruit development. These results underscore the importance of the timing of harvests in maximizing nutritional quality, with initial harvest at the green stage advised for protein preservation and yellow-red desired for mineral status. The findings emphasize the potential of agroforestry systems, especially home gardens, to improve fruit nutritional quality.