Eating Red in Ethiopia: Variation in Composition of Coffee Cherry Husks by Altitude and Soaking Solution

Despite evidence that the husk of the coffee cherry, ( Coffea arabica ) is rich in carbohydrates, proteins, lipids, minerals, and bioactive compounds, it is discarded during processing in Ethiopia, left to rot and leach into the environment for every ton of coffee beans processed. Coffee cherry husks were gathered from smallholder coffee farms at low, medium and high altitudes in the southern region of Ethiopia; Debub Bench District, Leku District and Chena District, respectively. Results affirm that coffee cherry husks contain key nutrients and phenolic compounds. Additionally, nutrient composition varies by altitude: generally, cherry husks sampled from higher altitudes have lower ash, carbohydrates, dietary fiber, and total minerals, but greater protein, lipid, and caffeine content. In contrast, coffee cherry husks from lower altitudes have higher carbohydrates, dietary fiber, and total minerals, but lower protein, lipid, and caffeine content. Furthermore, husks soaked in a chemical solution aimed at reducing the level of anti-nutritional factors showed significantly lower antinutrients and mineral composition. Husks soaked in a Ca(OH) ₂ solution were significantly lower/higher in protein, Dietary fiber, P, Li, Mg, S, V, Mn, Zn, As, Se, Cd, Ni, and Mo than husks soaked in a NaOH or Na ₂ SO ₄ solutions., The results of this study demonstrate that coffee cherry husks are a good source of protein, dietary fiber, and minerals including iron (Fe) and zinc (Zn). Thus, the content of the coffee cherry husk could provide nutrients missing from the diets of many Ethiopians. Soaking cherry husks in calcium hydroxide (Ca(OH) ₂ ) can reduce anti nutritional properties and heavy metals, allowing cherry husks to be used in different ways. These findings highlight the significant nutritional and functional potential of coffee cherry husks as a sustainable, value-added food resource rather than an agricultural waste product. Promoting appropriate processing methods such as Ca(OH)₂ treatment could enhance food security, environmental sustainability, and economic opportunities for coffee-producing communities in Ethiopia. Further research should explore product development, sensory acceptability, and scalability of processing methods to facilitate integration into local food systems. Such efforts could transform coffee by-products into innovative nutrition-sensitive interventions that support public health and rural livelihoods.