Red Pepper Fermentation with Geothermal Mineral Water: Impact on Nutritional Profile and Quality Characteristics

Red bell pepper (Capsicum annuum L.) is a valuable source of health-promoting phytochemicals and essential minerals. This study investigated the impact of using geothermal mineral water versus tap water as the fermentation medium on the nutritional, physicochemical, and sensory properties of two red bell peppers (cultivars ‘Yecla F1’ and ‘Salomon F1’). The results showed that fermentation caused a significant decrease in the content of L-ascorbic acid (by 30–50%), carotenoids (~30%) and polyphenols (by 25–30%), with lower nutrient losses observed in peppers fermented with geothermal water. In addition, fermentation with geothermal water increased the calcium, magnesium, and potassium contents of the peppers compared to tap water. Sensory analysis showed that the pepper cultivars had a greater impact on the overall sensory quality than the fermentation medium or the evaluation time, although geothermal water had a positive effect on the texture of the fermented peppers. These results suggest that geothermal water may be a beneficial alternative to traditional water sources in vegetable fermentation, improving both the nutritional and sensory properties of the final product.