# The Role of Fermented Vegetables as a Sustainable and Health-Promoting Nutritional Resource
## 3. Femented Vegetables
### Mechanisms of the Fermentation Process  
Fermentation is the most ancient biotechnological technique for preserving vegetables. Since vegetables are highly perishable, various preservation methods such as canning, refrigeration, and freezing have been established to extend their shelf life. However, in underdeveloped and developing nations, these preservation methods are often unavailable, forcing reliance on traditional, well-established natural preservation techniques. Fermentation continues to be the longest-standing biotechnological approach to vegetable preservation, resulting in alterations to organoleptic properties and improvements in nutritional quality [134]. Historically, food fermentation has been utilized to extend the shelf life of food substrates that would otherwise spoil rapidly, being an essential practice during periods of scarcity [127], whilst concurrently enhancing flavor profile [135]. It also serves to decrease the toxicity of raw materials, control pathogenic microorganisms, and facilitate digestion [136]. Fermented foods are primarily categorized based on the substrate used, such as cereals, dairy, legumes, and vegetables [137]. These categories vary according to their main food substrate and the type of fermentation employed, which may include defined starter cultures, back-slopped cultures, or spontaneous fermentation. Fermented foods serve as a substantial source of beneficial microorganisms that may function as potential probiotics [138], as well as bioactive peptides [139], phytochemicals, and vitamins [140]. In addition, various dietary intervention strategies and regular eating habits can influence the composition and/or diversity of the gut microbiota [13,141]. Consequently, their metabolites, such as SCFAs, phenolic compounds, tryptophan, and bile metabolites can modulate the routes that transmit signals from the gut to the brain [142, 143, 144]. Regarding the fermentation process, it is important to consider the following issues: (i) the production of fermented foods is affected by a range of environmental factors and processing conditions [145]; (ii) the genetic polymorphisms of starter cultures differ in a way that indicates their geographical provenance [146]; (iii) the scale of production and the conditions under which manufacturing occurs can partly account for the differences observed in the microbiome of fermented foods, influenced by geographical context [147]; (iv) distinct communities of LAB were identified in fermented products, varying by the geographical zone of production and the types of starter cultures used [148]; and (v) vegetable foods produced via commercial fermentation typically contained higher levels of LAB compared to those produced via artisanal methods [149], with the viral community also showing stronger ties to geographical location in kimchi samples [150], although certain non-vegetable artisanal products, such as cheese, may serve as a rich source of novel functional microbial strains [151]. Table 1 presents the fermentation processes of several vegetables, a practice rooted in centuries of tradition in East Asian countries. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Fementemented** & **Country** & **Microorganisms Involved** & **Bioactive Compounds** & **Health Benefits** & **References** \\ \hline Tempeh (tempe)/Soybean & Indonesia & _Ritzungs_ spp. & Riboflavin, niacin, iron, vitamin & Antioxidant, anticancer, parliamentary, parliamentary, and (mainly linoleic acid) & [152, 153, 154] \\ \hline Natto (Douchi and Temple)/Soybean & Japan (China and Indonesia) & _Rellias subtilis_ var _anto_, _Aspergillus oryzae_, and _Mucor racemus_ & Peptides, rattoikasinase enzyme & Antimicrobial, anticancer, antioxidant, and anti-qing effects; \\ \hline Miso/Soybean & Japan & _Aspergillus soils_, _A.