Traditional vegetable preservation technologies practiced in Acholi subregion of Uganda improves mineral bioavailability but impacts negatively on the contribution of vegetables to household needs for micronutrients

Abstract

The impact of traditional African preservation methods on the contribution of veg etables to household micronutrient needs (Recommended Dietary Allowance: RDA) has largely remained unquantified. Using Acholi subregion of Uganda as a case area, this study examined using the predominant vegetables consumed in fresh and pre served forms (cowpeas—Vigna unguicullata, okra/lady fingers—Abelmoschus esculen tus, Malakwang—Hibscus cannabinus, and eggplants—Solanum melongena), the effect of major traditional vegetable preservation methods (sun drying, boiling and sun dry ing, and salting and sun drying) on the contents of micronutrients (vitamin A, iron, zinc, calcium, magnesium, and phosphorus), the levels of antinutritional factors (total polyphenols, oxalate, tannins, and phytate), bioavailability of iron and zinc, and the contribution of vegetables to the cumulative annual household RDA for micronutri ents. Laboratory analysis showed that all the preservation methods, except the sun drying method reduced the contents of micronutrients by 20%–82% (p ≤ .05). The contents of antinutritional factors reduced by 1%–80% while in vitro bioavailability of iron and zinc increased by 21%–296% (p ≤ .05). Nutritional computation revealed that except for calcium, the preservation methods combined, reduced the contribution of the vegetables to cumulative annual RDA for other micronutrients by 28%–60%. These results demonstrate that improvements in bioavailability of essential nutrients (iron and zinc) by traditional preservation methods investigated are associated with significant loss of micronutrients which culminates in significant reduction in the con tribution of cultivated vegetables to household RDA for micronutrients. Traditional African preservation methods should be optimized for nutrient retention.

Description

Acknowledgement: This study was supported by “Nurturing M.Sc. Agri-Enterprise Development and M.Sc. Food Security and Community Nutrition at Gulu University for Internationalization Project” with funding from the Regional Universities Forum for Capacity Building in Agriculture (RUFORUM) (Grant Number: RU 2014 NG 13). RUFORUM played no role in the design, analysis or writing of this BIGHAGHIRE Et Al. |  601 20487177, 2021, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/fsn3.1931 by Readcube (Labtiva Inc.), Wiley Online Library on [21/05/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License article. The authors are grateful to the district, subcounty, and local council leaders, research assistants, and rural communities of Acholi Sub-region of Uganda for their active participation during data collection.

Keywords

household micronutrient requirements, nutrient bioavailability, nutrient losses, traditional African vegetable preservation

Citation

Bighaghire, R., Okidi, L., Muggaga, C., & Ongeng, D. (2021). Traditional vegetable preservation technologies practiced in Acholi subregion of Uganda improves mineral bioavailability but impacts negatively on the contribution of vegetables to household needs for micronutrients. Food Science & Nutrition, 9(2), 589-604.