Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruit and Vegetables, Haid-und-Neu-Str. 9, 76131 Karlsruhe, Germany.
Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruit and Vegetables, Haid-und-Neu-Str. 9, 76131 Karlsruhe, Germany; Jomo Kenyatta University of Agriculture and Technology, Department of Food Science and Technology, P.O. Box 62000, 00200 Nairobi, Kenya.
Int J Food Microbiol. 2021 Mar 16;342:109056. doi: 10.1016/j.ijfoodmicro.2021.109056. Epub 2021 Jan 17.
The interest in the consumption of African indigenous leafy vegetables increased in African countries, e.g. Kenya, within the last years. One example of African indigenous leafy vegetables is African nightshade (Solanum scabrum) which is nutritious, rich in proteins and micronutrients and therefore could contribute to a healthy diet. African nightshade has several agricultural advantages. However, the most important disadvantage is the fast perishability which leads to enormous post-harvest losses. In this study, we investigated the fermentation of African nightshade as a post-harvest processing method to reduce post-harvest losses. The two lactic acid bacterial starter strains Lactiplantibacillus plantarum BFE 5092 and Limosilactobacillus fermentum BFE 6620 were used to inoculate fermentations of African nightshade leaves with initial counts of 10-10 cfu/ml. Uninoculated controls were conducted for each fermentation trial. Fermentations were performed both in Kenya and in Germany. The success of the inoculated starter cultures was proven by the measurement of pH values and determination of lactic acid concentration. Lactobacilli strains dominated the microbiota of the starter inoculated samples in contrast to the non-inoculated controls. This was supported by classical culture-dependent plating on different microbiological media as well as by the culture-independent molecular biological methods denaturing gradient gel electrophoresis and 16S rRNA gene high-throughput amplicon sequencing. We could demonstrate that the use of the selected starter cultures for fermentation of African nightshade leaves led to controlled and reliable fermentations with quick acidification. Thus, controlled fermentation with appropriate starter cultures is a promising method for post-harvest treatment of African nightshade leaves.
近年来，非洲国家（例如肯尼亚）对食用非洲本地绿叶蔬菜的兴趣有所增加。非洲本地绿叶蔬菜的一个例子是非洲龙葵（Solanum scabrum），它营养丰富，富含蛋白质和微量营养素，因此有助于健康饮食。非洲龙葵具有几个农业优势。然而，最重要的缺点是快速腐烂，这导致了巨大的产后损失。在这项研究中，我们研究了发酵非洲龙葵作为一种产后加工方法来减少产后损失。使用两种乳酸菌 starter 菌株植物乳杆菌 BFE 5092 和发酵乳杆菌 BFE 6620 接种非洲龙葵叶发酵，初始计数为 10-10 cfu/ml。每个发酵试验都进行了未接种对照。在肯尼亚和德国都进行了发酵。通过测量 pH 值和确定乳酸浓度来证明接种 starter 培养物的成功。与未接种对照相比，乳酸菌菌株在接种 starter 的样品中主导了微生物群。这得到了传统的基于培养的不同微生物培养基平板计数以及非培养的分子生物学方法变性梯度凝胶电泳和 16S rRNA 基因高通量扩增测序的支持。我们能够证明，使用选定的 starter 培养物发酵非洲龙葵叶可导致快速酸化的受控和可靠发酵。因此，使用适当的 starter 培养物进行受控发酵是非洲龙葵叶产后处理的一种有前途的方法。
