The main objective of the study was to determine the effects of different fermentation parameters on kefir quality. Kefir samples were produced using kefir grains or natural kefir starter culture, and fermentation was carried out under normal or modified atmosphere (10% CO(2)) conditions. The microbiological (lactobacilli, lactococci, Lactobacillus acidophilus, Bifidobacterium spp., and yeasts), chemical (pH, lactic acid, total solids, protein, ethanol, exopolysaccharide contents), rheological, and sensory properties of kefir samples were investigated during a 21-d storage period. The use of different fermentation parameters or the choice of grain versus natural kefir starter culture did not significantly affect the content of microorganisms. Lactobacilli, lactococci, and yeast contents of kefir samples varied between 9.21 and 9.28, 9.23 and 9.29, and 4.71 and 5.53 log cfu/mL, respectively, on d 1 of storage. Contents of L. acidophilus and Bifidobacterium spp. were between 5.78 and 6.43 and between 3.19 and 6.14 log cfu/mL, respectively, during 21 d of storage. During the storage period, pH, lactic acid (%), total solids (%), protein (%), acetaldehyde, and ethanol contents of kefir samples ranged from 4.29 to 4.53, from 0.81 to 0.95%, from 7.81 to 8.21%, from 3.09 to 3.48%, from 3.8 to 23.6 mg/L, and from 76.5 to 5,147 mg/L, respectively. The exopolysaccharide contents of the samples decreased during 21 d of cold storage; the samples fermented under modified atmosphere had relatively higher exopolysaccharide contents, indicating higher potential therapeutic properties. The kefir samples exhibited non-Newtonian pseudoplastic flow behavior according to the power law model. According to the sensory results, kefir produced from natural kefir starter culture under CO(2) atmosphere had the highest overall evaluation score at d 1.

It is widely known that the use of medicinal plants and probiotics as feed additives has a positive effect on growth, non-specific immune system, and resistance to diseases in aquaculture. This study examines the effects of dietary supplementation with sage (Salvia officinalis) and myrtle (Myrtus communis), alone or in combination with a probiotic mixture (PM) on growth, intestine microflora and histology, some antioxidant enzymes activities in the muscle tissues of rainbow trout (Oncorhynchus mykiss) and disease resistance against Vibrio anguillarum. For this purpose, fish were fed with a control diet of 1% sage, 1% myrtle, 1.1% probiotic mixture, 1% sage +1.1% PM and 1% myrtle+1.1% PM supplemented diets for 60 days. At the end of the trial, the fish fed the diets supplemented with myrtle and sage + PM showed a positive effect on feed conversion ratio. According to the histological assessment, the villi length, villi width and goblet cell numbers in the intestines of fish in all groups increased compared to the control. Superoxide dismutase activity in the muscles of fish in the PM group was higher than the fish in the other groups (p<0.05). The malondialdehyde activity was unaffected with the exception of the fish in the sage group (p<0.05). The lactic acid bacteria count in the intestines increased in fish fed the sage + PM (p<0.05). Fish fed the diets supplemented with sage + probiotic mixture, probiotic mixture, myrtle + probiotic mixture, and myrtle saw a significant reduction in mortality (0-32.5%) due to V. anguillarum compared to the control (63.2%) (p<0.05). In conclusion, the use of probiotics, sage and myrtle in combination as a feed supplement showed a positive effect on the growth performance, intestinal microflora and histology, and antioxidant enzymes activities and disease resistance in rainbow trout.

Water kefir is a fermented probiotic beverage produced by fermentation of dried sugary fruits and sugar using water kefir grains. Sucrose is used as a sugar source in the traditional production of water kefir. The aim of this study is to determine the effects of grape molasses, honey and unrefined sugar on water kefir grains instead of sucrose. In the study, 4 groups were formed: grape molasses (10 g), honey (10 g), unrefined sugar (10 g) and refined sugar (10 g). 2 g of water kefir grain and 500 mL of drinking water were used for each group. And each group samples were fermented for 25°C 48 hours. The study continued for 5 weeks. The pH values and the titratable acidity values of water kefir samples and the weight of water kefir grains were determinated once every two day, while microbiological analyzes (Lactobacillus spp., Lactococcus spp. and yeast contents) and ethanol content of samples were determinate once every 15 days. In this study; it has been observed that the use of different sugars has no significant effect on the weights of the water kefir grains. In addition, it was determined that the Lactococcus spp. and yeast amounts in the water kefirs were higher in the samples produced by using honey and grape molasses. As a result, it was revealed that grape molasses, honey and unrefined sugar could be used as fermentation substrate in production of water kefir. At the same time, water kefir can be shown as an alternative fermented product for vegan consumers with allergies to dairy products.