POST-HARVEST HANDLING AND VALUE ADDITION OF AFRICAN INDIGENOUS VEGETABLES IN WESTERN KENYA

Abstract

African Indigenous Vegetables (AIVs) are the major source of micronutrients in western Kenya and in Africa at large. However, AIVs utilization is not fully exploited because they are perishable. As a result, the vegetables are not available throughout the year. The study involved three AIVs Amaranthus (Amaranthus ssp), spider plant (Cleome gynandra) and nightshade (Solanum spp). The objectives of the study were to determine AIVs processing methods in western Kenya; to determine the effects of some post-harvest handling techniques on nutritional composition; to assess consumer acceptability of both developed and local AIVs and to test the efficiency of mixed modes solar dryer over direct solar drying. A survey was done in Busia, Uasin Gishu and Trans Nzoia counties to determine the AIVs processing methods in western Kenya. To determine the effects of processing techniques on the nutritional composition, minerals analysis was done using Atomic Absorption Spectrophotometer (ASS) and flame photometer. The leaves were subjected to different treatments; exposed to direct sun, others were preserved under the shade. Recipes for the three varieties were developed and a panel of 51 consumers invited to participate in acceptability tests. The vegetables were ranked on taste, color, aroma, texture and overall acceptability. The performance of mixed mode solar dryer was compared to Mace Foods dryer (direct mode). Data analysis was done using SAS version 9.3. Means were separated by least significant difference at P ≤ 0.05. T-test was used to compare vegetable preferences in western Kenya. AIVs (72%) were mostly grown after maize (92%). Boiling (22%) was the most common processing technique used by the farmers. There was no significant difference on preservation techniques on the elements at P≤ 0.05. However, vitamin C loss was greater during sun drying than shade preservation. From solar drying, the lowest and highest ambient temperatures recorded were 21.30C and 41.10C respectively. The mixed modes solar dryer recorded temperatures ranged between 23.00C to 72.10C. Mace Foods dryer temperatures ranged from 22.00C to 59.00C. The moisture content of the solar dried AIV ranged from 4.5% to 8.2 % while that from Mace Foods dryer ranged from 9.2% to 12.8 %. Findings of acceptability studies revealed that a combination of spider plant, nightshade and amaranthus prepared using cream was ranked highly (8.16± 1.07) followed closely by EX-ZIM amaranthus variety (7.29± 1.03) at P≤ 0.05. Bitter local nightshade (7.04±1.04) was preferred to the developed SS-49 variety (6.33±1.14) at P≤ 0.05. From the study findings consumers should be both enlightened on sound preservation techniques and be availed with seeds of the improved AIVs varieties for planting. Finally, the mixed modes solar drying technology should be adopted by farmers for AIVs preservation.