Mbondo Naomi N, Owino Willis O, Ambuko Jane, Sila Daniel N
Department of Food Science and Technology Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya.
Department of Plant Science and Crop Protection University of Nairobi Nairobi Kenya.
Food Sci Nutr. 2018 Mar 13;6(4):814-823. doi: 10.1002/fsn3.623. eCollection 2018 Jun.
African eggplants ( L.) are a rich source of bioactive compounds and functional constituents that are beneficial to human health. However, the short shelf life of these vegetables can be a major cause of postharvest losses especially during peak harvesting season. Drying is one of the most convenient technologies for the production of shelf stable food products. However, drying can lead to considerable loss of the available bioactive compounds due to thermal degradation depending on the drying method and temperature conditions. This study investigated the effect of four drying methods (solar, oven, vacuum, and freeze) on the retention of total phenolics, beta-carotene, antioxidant capacity, and lycopene in five African eggplant () accessions (sangawili, manyire green, S00047A, AB2, and aubergine blanche). Samples were dried up to ~10% moisture content. The fresh and dried samples were analyzed for total phenolic content, antioxidant capacity, beta-carotene content, and the lycopene content. In the fresh state, beta-carotene, total phenolic content, and free radical scavenging activity ranged between 14.75 ± 0.50 and 29.50 ± 0.77 mg/100 g db, 751.21 ± 1.73 and 1,363.95 ± 2.56 mg/100 g GAE db, and 99.58 and 325.61 mg/ml db IC value, respectively. The accession S00047 showed highest total phenolic content and lowest IC value in the fresh samples. The results also showed that total phenolic content, antioxidant capacity, and beta-carotene contents were significantly ( < .05) affected by drying method and drying temperature with freeze-drying presenting the highest retention. Overall, 36.26%s-95.05% (total phenolics) and 31.44%-99.27% (beta-carotene) were retained during freeze-drying. Lycopene was only detected in the dried samples of the accession manyire green but absent in all the fresh samples of all the accessions. This study demonstrates that freeze-drying was the most effective in retaining the highest bioactive compounds in African eggplants.
非洲茄子（L.）富含对人体健康有益的生物活性化合物和功能成分。然而，这些蔬菜的货架期较短，这可能是采后损失的主要原因，尤其是在收获高峰期。干燥是生产货架期稳定食品最便捷的技术之一。然而，根据干燥方法和温度条件，干燥可能会因热降解导致大量可用生物活性化合物损失。本研究调查了四种干燥方法（太阳能、烤箱、真空和冷冻）对五个非洲茄子（）品种（桑加维利、马尼雷绿、S00047A、AB2和白茄子）中总酚、β-胡萝卜素、抗氧化能力和番茄红素保留率的影响。将样品干燥至水分含量约为10%。对新鲜和干燥样品的总酚含量、抗氧化能力、β-胡萝卜素含量和番茄红素含量进行分析。在新鲜状态下，β-胡萝卜素、总酚含量和自由基清除活性分别在14.75±0.50至29.50±0.77毫克/100克干重、751.21±1.73至1363.95±2.56毫克/100克没食子酸当量干重以及99.58至325.61毫克/毫升干重IC值之间。S00047品种在新鲜样品中总酚含量最高，IC值最低。结果还表明，干燥方法和干燥温度对总酚含量、抗氧化能力和β-胡萝卜素含量有显著影响（<0.05），冷冻干燥的保留率最高。总体而言，冷冻干燥过程中总酚保留率为36.26% - 95.05%，β-胡萝卜素保留率为31.44% - 99.27%。仅在马尼雷绿品种的干燥样品中检测到番茄红素，所有品种的新鲜样品中均未检测到。本研究表明，冷冻干燥在保留非洲茄子中最高生物活性化合物方面最为有效。
