Historically recognized as a valuable nutritional source, milk contains essential carbohydrates, proteins, and fats that play diverse functional roles in the human body. While the functional roles of milk nutrients and their derivatives are acknowledged, the corresponding functional foods for each milk component remain inadequately documented in Korea. This review aims to describe the functional roles of milk components and their derivatives, as well as assess the landscape of functional food products available in the Korean market. Milk components demonstrate noteworthy functions such as preventing muscle wasting, fortifying bones, aiding in weight control, stabilizing nerves, and serving as prebiotics. Despite these known functions, there exists a plenty of functional substances within milk that have not been comprehensively investigated. Presently, only a limited number of milk-derived functional ingredients are registered in Korea, with a few making their way into commercialization. To advance this field, scientists and industries need research effort to uncover novel functions of milk ingredients and subsequently introduce innovative products to the market. This proactive approach not only promises to broaden the spectrum of functional ingredients but also stands to positively impact the domestic health functional food market and the dairy industry. The development and introduction of new products derived from milk may hold the potential to significantly contribute to the diversification of functional ingredients, fostering a healthier and more robust health food market.

Bacteria get stressed and damaged during freeze-drying process for commercialization and this result in loss of its effect. Viability is important for its efficacy, but this drying process can deteriorate viability by damaging the integrity of the cell membrane as well. In this study, we propose 0.03 M histidine for rehydration of freeze-dried probiotics to improve their viability. The freeze-dried bacteria mixture with 0.03 M histidine showed augmented survivability during in vitro simulated gastric and duodenum stress conditions and increased viability during 60 min rehydration. It exhibited a significantly increased adherence ability of lyophilized bacteria to the HT-29 cell-line. Therefore, this shows possibility of probiotics commercialization with damage of lyophilization restored and survivability ameliorated.

The purpose of this study was to demonstrate the neuroprotective effect of heat-treated fermented black beans. The production of fermented black beans was optimized using Lactiplantibacillus plantarum SMF470 and L. plantarum SMF796 strains isolated from kimchi as starters. Compared to heat-treated black bean extract, heat-treated fermented black beans showed significantly higher DPPH and ABTS radical scavenging activities, as well as higher total polyphenol content (p <0.05). The neuroprotective effect through the gut-brain axis was evaluated using conditioned medium (CM) obtained by culturing heat-treated fermented black beans in intestinal cells (HT-29). The CMs of heat-treated fermented black beans from SMF470 and SMF796 showed a high protective effect on SH-SY5Y human neuroblastoma cells induced by oxidative stress from H2O2. Additionally, the CMs of heat-treated fermented black beans were found to protect SH-SY5Y cells from toxicity induced by MPP+. SMF470-CM and SMF796-CM significantly increased the expression of brain-derived neurotrophic factor (BDNF) in SH-SY5Y cells treated with MPP+, while lowering the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (p <0.05). Furthermore, SMF470-CM and SMF796-CM lowered the apoptosis-related Bax/Bcl-2 ratio. The results of this study suggest that heat-treated fermented black beans can be utilized as potential health functional materials for the prevention and improvement of degenerative brain diseases.

To suggest the development possibility of immunostimulating materials from lactic acid bacteria (LAB) postbiotics, Lactobacillus sakei/Leuconostoc mesenteroides were isolated from Kimchi. Next, two isolated LAB were cultured to prepare postbiotics (LABP) to measure macrophage activity. LABP significantly increased the production of macrophage stimulating factors such as nitric oxide, tumor necrosis factor-α, and interleukin-6. LABP-crude polysaccharides (CP) fractionated from LABP by EtOH precipitation not only showed more potent macrophage stimulating activity but also induced phagocytic activity in a dose-dependent manner. In addition, LABP-CP was identified as polysaccharides with a major monosaccharide composition of mannose (59.1%), glucose (23.0%), and galactose (14.0%) with high-molecular-weight of 103.5~126.7 kDa. In conclusion, postbiotics prepared from LAB isolated from Kimchi were confirmed to have industrial applications as a functional material with immunostimulating activity.

This study was investigated to the quality properties of yogurt added with natural additives (almond, corn, and hibiscus). The pH of all natural additives added samples was significantly lower than the control sample (p <0.05). The lightness of the corn added samples was significantly higher than the control sample (p<0.05). The redness of almond and corn samples were shown increase tendency with increasing almond and corn contents; the hibiscus samples was shown significantly higher than the almond and corn samples (p <0.05). The yellowness of the almond and hibiscus samples were shown significantly lower than the control sample (p<0.05), however, the corn samples was shown significantly higher than the control sample (p <0.05). In the sensory evaluation, overall traits of almond with 3%, corn with 9%, and hibiscus with 8% samples were shown higher score compared the control sample. These results showed that the yogurt added with almond, corn, and hibiscus was decreased pH and affected yogurt color. Considering the sensory evaluation results, we deduced appropriate added amounts when the almond, corn, and hibiscus added to the yogurt.

This study sought to confirm the inhibitory ability of Clostridioides difficile KCTC 5009 strain using the bacteriocin-producing Lactococcus lactis CJNU 3001 strain. For this purpose, bacterial culture and partially purified bacteriocin verified the antibacterial activity against C. difficile strain. As a result, both samples showed strong antibacterial activity against the target strain. Co-culture tests were performed to more closely analyze the competition between the two strains. As a result, a similar inhibitory effect was confirmed in RCM broth and CMM (colon model medium) broth. In particular, inhibition of C. difficile KCTC 5009 strain was not observed until the exponential phase of the growth of L. lactis CJNU 3001 strain, because bacteriocins were produced during that period. It was inferred that it actively suppressed the growth of the target strain after that. Therefore, as it was proven that the bacteriocin-producing L. lactis CJNU 3001 strain can effectively control C. difficile strain in co-cultures, it was judged that it could be an alternative for CDI (Clostridioides difficile infection) treatment.