###### Abstract  
Gastritis and gastric ulcers caused by stressors such as drinking are common. The ability of functional foods to protect the stomach more effectively and reduce the risk of side effects is of interest. The fermentation process can increase the preservation and bioactive compound content of kiwi fruits. This study produced fermented kiwi powder using two lactic acids separated from gold kiwi fruits. Gold kiwi pure (_Actinidia chinensis_ L.) was fermented using beneficial bacteria. Fermentation increased the content of bioactive compounds such as organic acids, flavonoids, and carotenoids. We investigated whether fermented gold kiwi (FGK) extract had antioxidant and gastric protective effects in an HCl/EtOH-induced gastritis animal model and pyloric ligation animal model. FGK increased radical scavenging activity in a dose-dependent manner. In the gastritis model, FGK inhibited inflammation-related factors such as iNOS, COX-2, IL-6, and TNF-\(\alpha\), while increasing the expression of the protective molecule PGE2. Furthermore, FGK administration improved gastric lesion site appearance, clinical symptoms, and mucosal thickness in rats. FGK also reduced gastric fluid volume, free acidity, total acidity, and pepsin activity in the pyloric ligation model. These results suggest that FGK can decrease the inflammatory response and protect the gastric mucosa. FGK therefore has the potential to prevent and treat gastritis and gastric ulcers.  
printed 2022 21 May 2022 21 May 2022 22 May 2022 2  
Kiwis are plants in the genus _Actinidia_ whose fruits are edible; kiwis grow primarily in temperate zones, and there are 64 varieties worldwide. Kiwi fruits contain bioactive compounds with various physiologically active substances, such as organic acid, flavonoids, and carotenoids [9]. Kiwi fruits have bioactivity compound content 2-3 times higher than that of apples and grapes and contain organic acids such as quinic acid, malic acid, and citric acid [10]. Kiwi fruits have been shown to have antioxidant activity, anticancer activity, and to improve constipation [11; 12; 13; 14].  
Ethylene production results in softening of the flesh of kiwis, decomposition, synthesis of fragrance and pigment components, and reduction of organic acids. Therefore, kiwis have a short shelf life and rapidly lose commercial quality during storage [15]. Research has been conducted to determine how to preserve the biologically active compounds in kiwis. Although various fermented kiwi products have been studied, most of these products are processed foods and beverages with low utilization [15; 16; 17].  
Recently, attempts have been made to improve the storage properties, nutritional quality, and physiological activity of fermented kiwi using various beneficial bacteria [18; 19]. Our lab has screened the ability of several lactic acid bacteria as starter cultures to produce valuable substances when used to ferment Jeju gold kiwi fruit puree. In the current study, kiwi fruit puree was fermented with _Lactococcus lactis_ VI-01 (KCTC 14351 BP) and _Lactobacillus paracasei_ VI-02 (KCTC 14352 BP), both of which were originally isolated from Jeju gold kiwi. We used this fermented gold kiwi (FGK) extract in an experimental gastric ulcer model and pyloric ligation model to investigate whether it exerted gastroprotective effects and could be used in the development of functional foods with therapeutic effects.