Nkolisa Ntombizandile, Magwaza Lembe S, Workneh Tilahun S, Chimphango Annie, Sithole Nkanyiso J
Discipline of Crop and Horticultural Science, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa.
Bioresources Engineering, School of Engineering, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa.
Heliyon. 2019 Aug 10;5(8):e02266. doi: 10.1016/j.heliyon.2019.e02266. eCollection 2019 Aug.
The aim of this study was to investigate the effect of low cost evaporative cooling system on the quality of two tomato cultivars, namely, 9065 jam and round tomatoes. Both the tomato cultivars were harvested from a smallholder farmer's field at Umsinga and stored for 20 days in one of the three storage conditions namely; cold room (CR), room temperature (RT) and evaporative cooling system (ECS) and sampling done every 5 days. The tomato samples were laid out as a factorial design with four replications. Results obtained proved that the storage conditions and storage period had a significant effect ( < 0.05) on the lycopene content (LC), antioxidants, total phenolic content (TPC) and ascorbic acid (AA) of the tomato samples. A decreasing trend with storage time was observed for antioxidants and TPC for both the cultivars whilst there was an increasing trend of AA and lycopene content on both the cultivars stored in the different storage conditions. Ascorbic acid was highest in samples stored in RT (0.173 mg/100g for round tomatoes; 0.172 mg/100g for 9065 jam tomatoes), second highest in samples stored under ECS (0.16 mg/100g for round; 0.17 mg/100g for 9065 jam) and lowest in samples inside the CR (0.11 mg/100g; 0.12 mg/100g for 9065 jam). Lycopene content was highest in samples stored in RT (45.31 mg/100g for round tomatoes; 52.9 mg/100g for 9065 jam tomatoes) second highest in samples stored under ECS (32.46 mg/100g for round tomatoes; 42.98 mg/100g for 9065 jam tomatoes) and lowest in samples inside the CR (14.16 mg/100g for round tomatoes; 8.79 mg/100g for 9065 jam tomatoes). Total phenolic content was highest in samples stored in CR (0.17 mg/100g GAE for round tomatoes; 0.19 mg/100g GAE for 9065 jam tomatoes) second highest in samples stored under ECS (0.124 mg/100g GAE for round tomatoes; 0.126 mg/100g GAE for 9065 jam tomatoes) and lowest in samples inside the RT (0.11 mg/100g GAE for round tomatoes; 0.12 mg/100g GAE for 9065 jam tomatoes). Antioxidant activities were highest in samples stored in CR (2.05 mg/100g for round tomatoes; 2.03 mg/100g for 9065 jam tomatoes), followed by samples stored under ECS (1.82 mg/100g for round tomatoes; 1.96 mg/100g for 9065 jam tomatoes) and lowest in samples inside the RT (1.02 mg/100g for round tomatoes; 1.07 mg/100 g for 9065 jam tomatoes). The correlation relationship among cultivars was positive and PCA proved that the cultivars were similar. Although CR provided the best storage condition for the investigated parameters, the results provided sufficient evidence that ECS can be the best method to increase shelf life in rural communities due to its association with cost reduction.
本研究的目的是调查低成本蒸发冷却系统对两个番茄品种（即9065果酱番茄和圆形番茄）品质的影响。这两个番茄品种均从乌姆辛加的一位小农户农田中收获，并在以下三种储存条件之一中储存20天：冷藏室（CR）、室温（RT）和蒸发冷却系统（ECS），且每5天进行一次采样。番茄样本按析因设计排列，重复四次。所得结果证明，储存条件和储存期对番茄样本的番茄红素含量（LC）、抗氧化剂、总酚含量（TPC）和抗坏血酸（AA）有显著影响（<0.05）。两个品种的抗氧化剂和TPC均随储存时间呈下降趋势，而在不同储存条件下储存的两个品种的AA和番茄红素含量均呈上升趋势。抗坏血酸在室温储存的样本中含量最高（圆形番茄为0.173毫克/100克；9065果酱番茄为0.172毫克/100克），在ECS储存的样本中次之（圆形番茄为0.16毫克/100克；9065果酱番茄为0.17毫克/100克），在冷藏室中的样本中最低（圆形番茄为0.11毫克/100克；9065果酱番茄为0.12毫克/100克）。番茄红素含量在室温储存的样本中最高（圆形番茄为45.31毫克/100克；9065果酱番茄为52.9毫克/100克），在ECS储存的样本中次之（圆形番茄为32.46毫克/100克；9065果酱番茄为42.98毫克/100克），在冷藏室中的样本中最低（圆形番茄为14.16毫克/100克；9065果酱番茄为8.79毫克/100克）。总酚含量在CR储存的样本中最高（圆形番茄为0.17毫克/100克没食子酸当量；9065果酱番茄为0.19毫克/100克没食子酸当量），在ECS储存的样本中次之（圆形番茄为0.124毫克/100克没食子酸当量；9065果酱番茄为0.126毫克/100克没食子酸当量），在RT中的样本中最低（圆形番茄为0.11毫克/100克没食子酸当量；9065果酱番茄为0.12毫克/100克没食子酸当量）。抗氧化活性在CR储存的样本中最高（圆形番茄为2.05毫克/100克；9065果酱番茄为2.03毫克/100克），其次是ECS储存的样本（圆形番茄为1.82毫克/100克；9065果酱番茄为1.96毫克/100克），在RT中的样本中最低（圆形番茄为1.02毫克/100克；9065果酱番茄为1.07毫克/100克）。品种间的相关关系为正，主成分分析证明品种相似。尽管CR为所研究的参数提供了最佳储存条件，但结果提供了充分的证据表明，由于ECS与成本降低相关联，它可能是农村社区延长货架期的最佳方法。
