Kombucha is a fermented tea manufactured by adding various microorganisms and sugars to brewed herb tea such as green tea and black tea. Its components and functions vary depending on ingredients, inoculated microorganism compositions, and fermentation conditions. Therefore, this study aims to examine which conditions affect kombucha properties and how these features are affected. Types of substrates, specifically plant-based foods, alter profiles of polyphenol, organic acids, carbohydrates, and protein amounts in kombucha. Long fermentation time raises polyphenol contents and high fermentation temperatures increase sourness in kombucha. Microbial composition of SCOBY, which is the symbiotic culture of bacteria and yeast used to inoculate microorganisms, change the kombucha microbiome that contributes to the chemical composition and functions of kombucha. Several studies have discovered that kombucha has health beneficial functions such as antioxidant activity, hepatic protective effects, antimicrobial effects, anti-diabetic effects, anti-inflammatory effects, and cholesterol reducing effects. These findings indicate that kombucha has high potential as a health functional food. However, future studies are needed to further determine the relationship of manufacturing conditions and functional properties of kombucha.
One of the most precise methods of tracking water movement and measuring moisture content during hydration process is the usage of magnetic resonance imaging (MRI). In this study, the target samples were dried “Robusta” green coffee beans, and a series of images was acquired through an MRI system during the entire hydration process. Coffee beans were immersed in a glass bottle and were placed in a 35 mm diameter RF coil throughout the whole experiment. A set of 64 images with a field of view of 26 mm×26 mm was acquired. The hydration process of intact dried green coffee beans lasted for 360 min and image data sets were acquired every 10 min with an optimal GRE pulse sequence developed. The MR images were analyzed in 2D and 3D imaging spaces. The results of 2D analysis showed that the changes in water penetration depth inside coffee beans during the hydration process could be visualized. In addition, the results of 3D analysis presented a clearer understanding of the hydration process of dried coffee beans. This study showed that changes in water distribution and physical dimensions of coffee beans during the hydration process in 2D and 3D imaging spaces were meserable, without disturbing the process, by means of the MRI technique.
1-Deoxynojirimycin (DNJ), an alpha-glucosidase inhibitor, has been used to prevent or treat type 2 diabetes. Low amounts of DNJ are found in mulberry leaf; however, a methodology is necessary to enhance the DNJ content of mulberry leaf extract (MLE) since increasing the amounts of DNJ is required for the prevention and treatment of type 2 diabetes. In this study, the DNJ content of MLE was increased through the optimization of the conditions for MLE fermentation by Lactobacillus plantarum SG-053, using response surface methodology (RSM). By single factor testing, the optimal conditions were identified as an inoculum concentration of 1%(v/v), an MLE concentration of 3°Bx, and no agitation. Based on a Plackett-Burman design, the following factors were considered to majorly affect the DNJ content in the MLE fermentation product: the initial pH, fermentation temperature, and fermentation time. By response surface methodology, the optimal conditions for MLE fermentation was found to have an initial pH of 5.5, a fermentation temperature of 31.9oC, and a fermentation time of 34 h. Under these optimal fermentation conditions, the DNJ content in MLE increased 3.59 times, or from 23.85 to 85.54 μg/mL.
Effects of heating methods (hot-air heating, roasting, and microwave radiation) and kernel characteristics on the expansion of whole grains from different botanical sources have been examined. Waxy brown rice which composed of hard endosperm with tightly adhering pericarps showed explosive expansion during heating. Scanning electron microscopy showed that starch granules in hard endosperm expanded during heating, forming porous internal structure. Meanwhile those in soft endosperm remained intact since moisture vaporized into the void surrounding the granules. Whole wheat which expanded to the least extent during heating showed the formation of large fissures between pericarp and seed coat, indicating improper rigidity of pericarps as well as endosperm texture for puffing. The degree of expansion and microstructure of kernel varied depending on the heating methods applied due to their different heat transfer characteristics. Hot-air heating resulted in the higher extent of expansion than roasting or microwave radiation. Whole grains heated by either roasting or microwave radiation showed not only similar extent of expansion but also internal microstructures, although roasting process created the formation of an agglomerated mass at the domain of endosperm due to the partial gelatinization of starches.
The pine bark extract was added during the beer manufacturing process to develop a functional beer using natural plant materials. Pilsner beer was prepared by adding 0-0.125% to the wort. Immediately before fermentation, extracts were added with yeast cultured twice for 48 hr, and fermentation was carried out at 25°C for 5 d and storage was carried out at 2°C for 15 d. In the experiment, pH, reducing sugars, soluble solid contents, specific gravity, alcohol contents, chromaticity, total flavonoids, total polyphenols, DPPH, and yeast number were tested during fermentation and storage to characterize. The pH, reducing sugar, soluble solid contents, specific gravity, and alcohol contents of the six samples were not significantly different during fermentation and storage. However, yeast number, flavonoids, polyphenols, and DPPH were higher at higher pine bark extract contents. L value in chromaticity was the highest in control, and a value and b value were higher as the amount of extract added. In the sensory test, beer with 0.05% pine bark extract showed the best color, sweetness and aroma. Therefore, it was judged that it is desirable to prepare beer by adding 0.05% pine bark extract to pilsner beer.
This research investigated the quality properties of yogurts added to barley (1, 2, and 3%) and tagatose or sucrose. After inoculation of S. thermophilus, pH, titratable acidity (TA), viscosity, and viable cell count were measured at 4 h intervals for 16 h and color value, antioxidant activity, and sensory evaluation were determined after fermentation in triplicate. In the case of yogurt containing only tagatose or sucrose, the pH was hardly decreased, but when 2-3% barley was added, the pH reached below 4.5 before 16 h. In addition, TA and viscosity tended to increase as barely was added. Viable cell count increased slowly in yogurt with tagatose, but rapidly increased when barley was added. As barley content increased, yellowness, redness, and antioxidant activity tended to increase, and significantly higher antioxidant activity in barley tagatose yogurt. Sour strength increased and significant difference in the sweetness was not observed when barley amount increased. Although there was no significant difference in overall acceptability, tagatose yogurt containing 3% barley scored the highest in preference. In conclusion, the fermentation rate of yogurt inhibited by the addition of tagatose is improved by the addition of barley, and the growth rate of lactic acid bacteria is considered to play a role.
In this study, the physicochemical traits of soybean (100-seed weight, seed coat rate, protein content, composition, and amino acid content) and the quality of tofu (texture and sensory characteristics) were evaluated in order to determine the features of six varieties (Saedanbaek, Daechan, Daepung2, Seonpung, Miso, Saegeum) in terms of textural and sensory characteristics of tofu. Regardless of cultivar, the order of amino acid composition rate was as follows: Glutamic acid > Aspartic acid > Arginine > Leucine > Lysine. Approximately 50-60% of tofu (dry weight) consisted of protein, and among the cultivars, Tofu made from Saedanbaek showed the highest amount of protein at 59%. It was followed by tofu made from Miso at 54%. The rest contained about 50% protein. According to the result of correlation, crude lipid (-0.933**), crude protein (0.961**), and total phosphorus (0.924**) were strongly correlated with tofu hardness, and such factors could be utilized as an indicator of tofu quality.
This research confirmed the diversity and characterization of halophilic microorganisms isolated from the various solar salterns, collected on the inside and outside of the country. To isolate strains, the marine agar medium was basically used and cultivated at 37oC for several days aerobically. After single colony isolation, a totally of 230 pure colonies were isolated and phylogenetic analysis was carried out based on the result of 16S rDNA sequencing, indicating that isolated strains were divided into 4 phyla, 12 families, 27 genera and 64 species. Firmicutes phylum, the main phyletic group, comprised 89.6% with 3 families, 17 genera and 52 species of Bacillaceae, Staphylococcaceae and Carnobacteriaceae. To confirm whether isolated strain can produce industrially useful enzyme or not, amylase, lipase, and protease enzyme assays were performed individually, showing that 177 strains possessed at least one enzyme activity. Especially 17 strains showed all enzyme activity tested. This result indicated that isolated strains have shown the possibility of the industrial application. Therefore, this study has contributed to securing domestic genetic resources and the expansion of scientific knowledge of the halophilic microorganisms community in solar salterns.
The diversity and characterization of microorganisms isolated from the soil around several ranches in Korea were confirmed in this study. To isolate halophilic microorganisms, the marine agar medium was basically used and cultivated at 37℃ for several days. After single colony isolation, a total of 116 pure colonies were isolated and phylogenetic analysis was carried out based on the result of 16S rDNA sequencing, indicating that isolated strains were divided into 4 phyla, 23 families, 30 genera and 51 species. To confirm whether isolated strain can be a candidate for the fermentation of diverse food ingredients, amylase, lipase, and protease enzyme assays were performed individually, showing that 92 strains possessed at least one enzyme activity. Especially 4 strains, identified to Jonesia quinghaiensis (isolate name: JSF 19-2), Halomonas alkaliantarctica (isolate name: JSF 21), Bacillus velezensis (isolate name: NWFY-36), and Staphylococcus capitis subsp. urealyticus (isolate name: MSY-5), showed all enzyme activity tested. Moreover, 17 strains showed the ability for auxin production. This result indicated that isolated strains have shown the possibility of the application for the food and feed industries. Therefore, this study has contributed to securing domestic biological resources and the improvement of hydrolytic enzyme activity by using isolated strains.
This study investigated the quality characteristics of 5 different types of food (beef tenderloin, Japanese Spanish mackerel, radish, blueberry and tofu) by applying liquid immersion freezing, which is one of the quick-freezing methods. Each sample was refrigerated by -20℃ conventional freezing or -70℃ liquid immersion freezing respectively. After thawing at 4℃, we examined drip loss, color value, hardness, and volatile basic nitrogen. The drip loss of -70℃ freezing condition was significantly reduced compared to -20℃ freezing condition in every sample except Japanese Spanish mackerel. There were less changes in color values of beef tenderloin, Japanese Spanish mackerel, radish in -70℃ condition than conventional freezing. The hardness of beef tenderloin, tofu was decreased and that of radish, blueberry was increased at -70℃ freezing in comparison to -20℃ freezing. By applying -70℃ freezing on beef tenderloin, we also found more decreasing tendency of volatile basic nitrogen compared to -20℃ freezing. In conclusion, the quality of general frozen foods, such as beef tenderloin, Japanese Spanish mackerel and blueberry, could be improved. The possibility of developing frozen tofu is also discovered by the application of liquid immersion freezing. These results could be meaningful as baseline data for researching and development of high-quality frozen foods.