Milk Kefir Research Articles

Kualitas Kefir Susu Sapi dengan Tambahan Madu Hutan Selama Penyimpanan Suhu Rendah

Kefir is a highly acidic dairy product with various health benefits. The addition of forest honey plays a role in improving the quality and taste of kefir. This study aimed to evaluate the effect of honey addition and storage time on the physicochemical and organoleptic properties of cow's milk kefir during refrigerator storage. The study was conducted with a 3´3 factorial randomized block design with three replications. The first factor was the added honey (0%, 5%, 10%, and 15%), and the second was the storage time (0, 7, and 14 days). Analysis of variance and Duncan's test were used to analyze the data. The results showed that the added honey significantly affected water activity (P <0.05). In addition, the high concentration of added honey increased the panelists’ preference for kefir acceptance. This study confirmed that the addition of honey and storage time significantly affected the characteristics of the cow's milk kefir. The best treatment was a 15% addition of honey with a storage time of 0 day.
 
 Keywords: honey, kefir, milk, physicochemical, storage time

Karakteristik Kefir Susu Sapi Dengan Penambahan Ekstrak Bunga Telang (Clitoria ternatea)

Kefir is made from a kefir seed starter consisting of L kefiri, genus Leuconostoc, Lactococcus, and Acetobacter that grow side by side. The addition of butterfly pea flowers extract to kefir can improve functional properties and sensory. The aim of this study was to investigate the physical characteristic, chemical characteristics, microorganisms, antioxidant activity, and organoleptic properties of cow’s milk kefir with the addition of butterfly pea flowers during storage at refrigerator temperature (1‒4°C). The research analysis used a completely randomized design with a 3x3 factorial pattern with three repetitions. The first factor was the addition of butterfly pea flowers (0%, 3%, and 6%), and the second factor was storage time (0, 3, and 6 days). The physical, chemical, antioxidant activity, and microorganism characteristics were tested using two-factor ANOVA and further tested by the Duncan test. Data on organoleptic properties were analyzed by the nonparametric Kruskal-Wallis and then verified using the Mann-Whitney test. The results showed that during storage the kefir increased the pH value and TAT value and decreased the viscosity and fat content. The inhibition of DPPH and the antioxidant capacity of the addition of butterfly pea flowers extract increased and decreased with the length of storage. Lactic acid bacteria (LAB) and the yeast did not change. Sensory hedonic test panelists prefer the color and aroma of kefir with the addition of telang flower extract. Sensory test of hedonic quality with the best characteristics, namely the addition of 6% butterfly pea flowers extract.
 
 Keywords: butterfly pea extract, kefir, storage organoleptic

Use of kefir-derived lactic acid bacteria for the preparation of a fermented soy drink with increased estrogenic activity

Fermented foods are receiving growing attention for their health promoting properties. In particular, there is a growing demand for plant-based fermented foods as dairy alternatives. Considering that soy is a vegetal food rich in nutrients and a source of the phytoestrogen isoflavones, the aim of this study was to select safe food microorganisms with the ability to ferment a soy drink resulting in a final product with an increased estrogenic activity and improved functional properties. We used milk kefir grains, a dairy source of microorganisms with proven health-promoting properties, as a starting inoculum for a soymilk. After 14 passages of daily inoculum in fresh soy drink, we isolated four lactic acid bacterial strains: Lactotoccus lactis subsp. lactis K03, Leuconostc pseudomesenteroides K05, Leuconostc mesenteroides K09 and Lentilactobacillus kefiri K10. Isolated strains were proven to be safe for human consumption according to the assessment of their antibiotic resistance profile and comparative genomics. Furthermore, functional characterization of the bacterial strains demonstrated their ability to ferment sugars naturally present in soybeans and produce a creamy texture. In addition, we demonstrated, by means of a yeast-based bioluminescence reporter system, that the two strains belonging to the genus Leuconostoc increased the estrogenic activity of the soybean drink. In conclusion, the proposed application of the bacterial strains characterized in this study meets the growing demand of consumers for health-promoting vegetal food alternatives to dairy products.

Preclinical study of goat milk kefir as an antihyperglycemic food

Background: Goat milk kefir is a functional food with numerous health benefits, including blood sugar control, cholesterol reduction, and improved digestive health. This study aims to determine the effect of kefir consumption on blood glucose levels in hyperglycaemic mice (Mus musculus) without affecting another blood chemistry. This study compared goat milk kefir products to other processed milk products considered to be capable of controlling and reducing blood sugar levels. Objective:This study aimed to compare goat milk kefir products to other processed food products considered to be capable of controlling and reducing blood sugar levels.Methods: Twenty-one mice, as experimental animals, were induced for 21 days with the high-fat and high fructose diet to increase blood sugar levels. After induction, mice were divided into 3 groups according to treatment, namely oral administration of additional distilled water (placebo), diabetasol® (positive control), and goat's milk kefir with each group consisting of 9 individuals. Results: Treatment showed significant effect on the blood glucose and β-ketone level. Diabetasol® and Goat kefir supplemented mice had a lower blood glucose level than control (p < 0.05) and goat kefir supplemented mice had lower blood β-ketone level than control and Diabetasol® (p< 0.05). Meanwhile, hematocrit and hemoglobin levels did not show significant differences between treatments.Conclusion: The results suggested that goat milk kefir has preclinical potential as an antihyperglycemic functional food without affecting other blood chemistry profiles.Keywords: Antihyperglycemic, blood sugar, goat kefir

CHEMICAL CHARACTERISTICS OF KEFIR COW’S MILK FORTOFICED ARABICA GROUND COFFEE DURING FERMENTATION


 
 
 The purpose of this study is to fine out the chemical characteristics of kefir cow’s milk fortified arabica ground coffee. The research was conducted in July to September 2020 at the Laboratory of Animal Product Technology and Microbiology, Faculty of Animal Husbandry, Udayana University. The study used a completely randomized design (CRD) with five treatments and three replications. The five treatments were: fermented cow’s milk kefir without fortification of Arabica ground coffee (P0), fermented cow’s milk kefir with 1% fortification of Arabica coffee (P1), fermented cow’s milk kefir with 2% fortified Arabica coffee (P2), cow’s milk kefir fermented with fortified Arabica coffee powder 3% (P3), cow’s milk kefir was fermented with fortified Arabica coffee powder 4% (P4). The observed variables were lactose content, fat content, protein content and pH value. The results showed that the chemical characteristics of cow’s milk kefir fortified with Arabica coffee during fermentation had a significant effect (P<0.05) on the fat content of pH but was not significantly different (P>0.05) on lactose and protein content was in all tre- atments. The conclusion of this study is that kefir fortified with 2%, 3%, and 4% Arabica ground coffee gave good results according to Codex standards.
 
 

CHEMICAL CHARACTERISTICS OF FERMENTED COW’S MILK IN LIGHT GREEN COCONUT FARM (Cocos nucifera L. var. varidis Hassk)


 
 
 The purpose of this research was to determine the chemical characteristics of fermented cow’s milk kefir in light green coconut shells (Cocos nucifera L. var. viridis Hassk). The research was conducted from August to Oc- tober 2020 at the Laboratory of Animal Products Technology, Faculty of Animal Science, Udayana University. The experimental design used in the study was a completely randomized design (CRD) with three treatments and five replications. The three treatments were fermented cow’s milk in a jar as a control (P0), and fermented cow’s milk in a light green coconut shell (Cocos nucifera L. var. viridis Hassk) without coconut meat (P1), cow’s milk fermented in light green coconut shell (Cocos nucifera L. var. viridis Hassk) with coconut meat (P2). The variables observed in the research were total acid, lactose content, fat content, and protein content. The research data were analyzed using variance, if the effect of the treatment was significantly different (P<0.05), it was followed by Duncan’s mul- tiple range test. The results showed that the total acid in P2 and P1 treatments were significantly (P<0.05) higher by 36.05% and 29.07% than the P0 treatment, but between P2 and P1 treatments were not significantly different (P>0,05). Lactose content, fat content, and protein content in all treatments (P2, P1 and P0) showed no significant differences (P>0.05). The conclusion of this study that fermented cow’s milk kefir in light green coconut shells (Co- cos nucifera L. var. Viridis Hassk) has an effect on total acid but does not affect lactose content, fat content, and protein content.
 
 

ORGANOLEPTIC QUALITY OF COW MILK KEFIR INCUBATED IN LIGHT GREEN COCONUT SHELLS (Cocos nucifera L. var. viridis Hassk)


 
 
 This research was conducted to determine the organoleptic quality of kefir incubated in light green coconut shells (Cocos nucifera L. var. viridis Hassk) with and without coconut meat, conducted from August to October 2020 at the Laboratory of Animal Product Technology and Microbiology, Faculty of Animal Husbandry, Udayana University. The experimental design used in this study was a completely randomized design (CRD) with three tre- atments and five replications. The three treatments were: P0 used a jar (control), P1 used light green coconut shell (Cocos nucifera L. var. viridis Hassk) without coconut meat, P2 uses light green coconut shell (Cocos nucifera L. var. viridis Hassk) with coconut meat. The variables observed: color, taste, aroma, texture and overall acceptance. The results of the organoleptic test were analyzed using the Kruskal Wallis test, if there was a significant differen- ce (P <0.05) followed by the Mann-Whitney test. The results showed that the organoleptic quality of cow’s milk kefir incubated in light green coconut shells (Cocos nucifera L. var. viridis Hassk) was not significantly different (P>0.05) in all treatments (P0, P1, P2). The conclusion from the results of this study shows that, incubated cow’s milk kefir in light green coconut shell (Cocos nucifera L. var. viridis Hassk) with and without coconut meat did not affect the organoleptic quality of kefir but panelists gave a response that led to preference.
 
 

THE EFFECT OF ADDITIONAL ARABICA GROUND COFFEE ON THE FERMENTATION PROCESS ON ORGANOLEPTIC QUALITY OF COW’S MILK KEFIR


 
 
 This study aims to determine the effect of adding arabica ground coffee to the fermentation process on the orga- noleptic quality of cow’s milk kefir. The experimental design used was a completely randomized design (CRD) with five treatments and three replications, namely kefir with the addition of 0% arabica ground coffee (P0), kefir with the addition of 1% arabica ground coffee (P1), kefir with the addition of 2% arabica ground coffee. (P2), kefir with the addition of 3% arabica ground coffee (P3) and kefir with the addition of 4% arabica ground coffee (P4). The va- riables observed include color, aroma, taste, texture and overall acceptance. Analysis on color, aroma and taste sho- wed significantly different results (P <0.05) with a numerical scale of 3-4.72 respectively from white to light brown, 2.76-4.88 from sour to coffee flavored and 2.76-4.68 from very sour to bitter acid. Analysis on texture showed that P0 and P1 were not significantly different (P> 0.05) but P2, P3 and P4 were significantly different (P <0.05) from P0 with a numerical scale of 3-3.52 from ordinary to slightly soft. The analysis of the level of liking on the overall acceptance shows that P0, P1 and P2 are not significantly different (P>0,05), but P3 and P4 are significantly diffe- rent (P<0,05) with a numerical scale of 3.08-4.36 from ordinary to like. Based on the results of this study, it can be concluded that the addition of 4% Arabica ground coffee is the most preferred by the panelists.
 
 

Biological activities and physiochemical properties of low-fat and high-fat coconut-based kefir

Coconut milk is a rich source of several nutrients and free of lactose which can be an excellent alternative to cow milk for lactose-intolerant consumers. This study aimed to investigate the potential of producing coconut-based kefir beverages using low-fat and high-fat coconut milk. The beverage was evaluated for pH values, titratable acidity, peptide content, antibacterial activity, antioxidant activity, and rheological properties. The results showed a significant increase in lactic acid bacteria and yeast after the fermentation for 24 h. The pH of the low-fat and high-fat coconut milk kefir declined to 3.77 ± 0.01 and 3.84 ± 0.01, respectively. The titratable acidity increased to 0.75 ± 0.04% and 0.66 ± 0.01% lactic acid, respectively. The fermentation with kefir grains significantly increased the peptides content of low-fat coconut milk to 0.7 ± 0.016 mg mL−1, and for high-fat coconut milk, it increased to 0.571 ± 0.038 mg mL−1. In addition, low-fat coconut kefir showed strong antibacterial growth inhibition and antioxidant activity. The apparent viscosity of the kefir beverage decreased with increasing shear rate and was higher at a lower temperature. The low-fat coconut kefir's flow behavior index (n) and consistency index (K) were 0.216 and 0.223. The consistency index (K) was 3.067 and 0.576 Pa s n at 5 and 25 °C, respectively. Moreover, the (n) values of high-fat coconut kefir were recorded as 0.422 and 0.581, and (K) values as 0.33 and 1.245 Pa s n. Therefore, low-fat coconut milk can be an alternative to cow milk in producing kefir-based beverages.

Lactose Content and Selected Quality Parameters of Sheep Milk Fermented Beverages during Storage.

The aim of the research was to evaluate lactose content and rheological, physical, chemical, and organoleptic parameters during the storage of fermented beverages made from sheep's milk. The research was carried out on natural, probiotic, and Greek-type yogurts, as well as kefir. The products were made using the thermostat method from the milk of 42 East Frisian sheep in the middle lactation period, in duplicate. Lactose contents, active and titratable acidity, color by the L*a*b*C*h* system, and rheological parameters (hardness, consistency, consistency, and viscosity) were tested, and organoleptic assessments were carried out on the first, seventh, fourteenth, and twenty-first days of storing the drinks at 4 °C. Of all drinks, the highest reduction in lactose after 21 days of storage was found to occur in kefir (52% reduction) and, among the yogurts, in the Greek yogurt (41% reduction). The product with the lowest lactose content, regardless of the storage period, was kefir. This indicates that kefir is more suitable than yogurt for people with partial lactose intolerance. Effects of both inoculation type and beverage storage time were shown to exist for all parameters. It was also found that kefirs suffered deterioration in most rheological parameters and, in general organoleptic evaluation in the final period of storage. Based on our analysis, the optimal storage time for natural yogurts and sheep's milk kefirs at 4 °C was 21 and 14 days, respectively.

Yeasts from Iranian traditional milk kefir samples: isolation, molecular identification and their potential probiotic properties.

Milk kefir is a fermented dairy product with numerous attributed health benefits due to the presence of a complex eukaryotic and prokaryotic microbiota. In this study, a total number of 26 yeast isolates were obtained from eight kefir samples from three different cities of Iran. The isolates belonged to Kluyveromyces marxianus, Saccharomyces cerevisiae, Pichia fermentans and P. kudriavzevii. The potential probiotic characteristics of the isolates were evaluated based on their ability to tolerate the stimulated condition of the gastrointestinal tract. In addition, hemolytic activity, adherence to different solvents, auto-aggregation, adhesion to the epithelial intestine-derived cells and antimicrobial activity of the selected isolates were evaluated. Overall, four yeast strains (three strains of S. cerevisiae and one strain of P. fermentans) showed resistance and survival ability against the gastrointestinal physiological conditions including acidic pH, presence of bile salt and digestive enzymes. They were able to grow at 37°C and had the capacity to adhere to epithelial intestine-derived cells. These results suggest that the selected strains can be proper candidates as probiotic yeast strains for the development of novel functional foods.

Tailoring the Optimized Fermentation Conditions of SCOBY-Based Membranes and Milk Kefir Grains to Promote Various Functional Properties.

Kombucha culture (named SCOBY-Symbiotic Culture of Bacteria and Yeasts) and milk kefir grains represent multiple consortia of wild microorganisms that include lactic acid bacteria, acetic acid bacteria and yeasts with valuable functional properties. Their fermentative potential provides a wide range of derivate metabiotics (prebiotics, probiotics, postbiotics and paraprobiotics) with valuable in vitro and in vivo benefits. This study targeted the evaluation of the functionality of a co-culture of SCOBY-based membranes and milk kefir grains, used as freeze-dried starter cultures, for the fermentation of a newly formulated medium based on black tea infusion, supplemented with bovine colostrum and sugar, in order to produce bioactive compounds with functional properties. The design and optimization of the biotechnological process were achieved by using the Plackett–Burman experimental design (six factorial points, three center points) and the response surface methodology and central composite design (three factorial points, six axial points and two center points in axial) tools. The statistical analysis and the mathematical modelling of the responses such as the pH, titratable acidity, antioxidant activity and antimicrobial activity (against Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Aspergillus niger) were investigated. Further, the composition of organic acids, polyphenols and flavonoids of the fermented product obtained under the optimized fermentation conditions was also analyzed. The fermentation of the medium containing 6.27% (w/v) bovine colostrum powder, 1.64% (w/v) black tea, 7.5% (w/w) sugar, pH 6.7, with an inoculum based of 0.36% (w/v) milk kefir grains powder and 0.5% (w/v) SCOBY-based membrane (both as freeze-dried culture), at 30 °C, for 5 days, in an aerobic stationary system, revealed an antifungal activity between 80 and 100% against Aspergillus niger, an antibacterial activity of 8–22 mm against Escherichia coli and Bacillus spp. And a titratable acidity of 445 °Th. The chemical composition of the obtained product had a positive impact on the functional properties of the fermented products in terms of the antimicrobial and antioxidant properties.

Comparison of composition, sensory properties and aroma compounds of kefir produced from donkey milk and cow milk

In this study, donkey milk and cow milk used for kefir production and the kefir samples were characterised based on compositional and microbiological properties, volatile aroma compounds, amino acid composition, and sensory analyses during storage for 21 days at 5 °C. Compared to cow milk kefir (CMK), donkey milk kefir (DMK) had lower contents of total solids, fat, and protein. Using donkey milk resulted in a weaker body characteristic in the kefir sample due to its low total solids content and the low ratio of casein. Acetaldehyde and acetic acid formation were at a remarkable level in DMK. Besides, the high lactose content of donkey milk caused more ethanol production in the kefir. Tyrosine, valine, and arginine were the primary amino acids in DMK. Donkey milk kefir was evaluated as acceptable in the aspect of sensorial properties such as taste and odour. Based on the present results, it could be concluded that a probiotic fermented beverage can be produced from donkey milk.

Milk kefir therapy improves the skeletal response to resistance exercise in rats submitted to glucocorticoid-induced osteoporosis.

Glucocorticoid-induced osteoporosis (GIO) has emerged as a challenge after long-term glucocorticoids (GCs) administration. Exercise has been an important non-pharmacological option, while medications modulate bone remodeling despite adverse effects. In this way, milk Kefir (MK) therapy stands out as a safe alternative to improve bone metabolism. Our study aimed to investigate the effect of MK associated to resistance exercise on bone loss in rats with GIO. For this, sixty male Wistar rats were divided into 2 groups: normal (N) and subjected to GIO, which was subdivided into 4 groups: control (C), milk kefir therapy (K), Exercise (Ex), and Exercise+K (ExK). GIO was induced by dexamethasone (7mg/kg - i.m.; 1×/wk, 5wk). MK was administered daily (1×/day; 0.7ml/animal) and the climb exercise with load was performed 3×/wk; both for 16wk. Femur was collected for assessment of bone microarchitecture, quality and metabolism. GIO markedly reduced trabecular bone volume density (BV/TV) (-35%), trabecular thickness (Tb.Th) (-33%), mineral content of femur (-26%) as well as bone collagen content (-56%). Bone strength and its biomechanical properties given by flexural strength (-81%), fracture load (-80%), and the number of osteocytes (-84%) were lowered after GIO. GCs reduced osteoblast number and function while increased osteoclast number, altering bone remodeling (p<0.05). On the other hand, ExK significantly improved bone microarchitecture and quality, marked by fractal dimension increase (+38%), cortical volume (+34%), BV/TV (+34%), Tb.Th (+33%), mineral content and collagen maturity, while reduced the space between trabecula (-34%). The Ex and ExK increased the number of osteocytes (p<0.05) and they were able to reverse the lower osteoblast number. Both treatments used alone significantly enhanced bone biomechanical properties, but the ExK showed a more significant improvement. ExK ameliorated bone strength and biomechanics (p<0.05) and stimulated bone formation and modulated bone remodeling (p<0.05). MK and exercise administered isolated or in association increased the percentage of collagen bone filling after GIO (p<0.05), but only ExK improved collagen maturity. Our results showed that MK associated to resistance exercise enhanced bone microarchitecture, quality and metabolism, being therefore an interesting tool to improve skeletal response during GIO.

Multi-Objective Optimization of Beverage Based on Lactic Fermentation of Goat’s Milk Whey and Fruit Juice Mixes by Kefir Granules

Numerous fruits are produced in Ecuador, of which about 40% are never eaten. In addition, fresh goat cheeses are in high demand. However, goat cheese generates goat milk whey with high contamination loads, and, therefore, it must be adequately treated before being discharged into ecosystems. This research aims to use a mixture of tree tomato, common strawberry juices, and goat’s milk whey, to be statically fermented by milk and water kefir grains (WKG) for 48 h. For this, a dual mixture design of L-optimal response surface methodology was carried out to find the conditions that maximized all the responses evaluated (lactic-acid bacteria and yeasts concentrations and the overall acceptability assessed on a 7-point scale). Experiments were carried out in San Gabriel, Ecuador. Temperatures during the day and night were 20.2 ± 0.3 °C and 18.7 ± 0.3 °C, respectively. Three conditions were selected, where the highest response values were reached. Complementary experiments demonstrated the validity of the models. When comparing the results of the present study with similar ones carried out previously, higher values were observed in the concentration of yeasts, which seems related to the presence of the WKG. It is concluded that they could be suitable functional beverage candidates.

Production of milks and kefir beverages from nuts and certain physicochemical analysis

Cashew, hazelnut, peanut, walnut, and almond were used to make nut milk and kefir in this study. Kefir starter culture was used to ferment cow and nut milks. Kefir samples were kept at 4 °C for 30 days and examined on the 1st, 15th, and 30th days. The highest energy contents were determined in hazelnut milk (73.71 kcal/100 g) and kefir made from hazelnut milk (74.89 kcal/100 g). During storage, the total sugar, total organic acid, and polyunsaturated fatty acid contents of kefir samples decreased, whereas the saturated fatty acid content and pH value increased. The unsaturated fatty acid content of nuts milk and respective kefir was higher than cow’s milk and kefir made from cow’s milk, while the saturated fatty acid level was lower. Volatiles, ethanol, and ethyl acetate, which were shown to be dominating among the aroma components, were highest in kefir made from cow’s milk.

Antibacterial Property and Metagenomic Analysis of Milk Kefir.

Milk kefir fermentation has been used in households for generations. Consumption of milk kefir has been associated with various health benefits, presumably from the probiotics of yeast and bacteria that make up the kefir grains. In addition, many of the microbes are known to produce novel antimicrobial compounds that can be used for other applications. The microbes living inside kefir grains differ significantly depending on geographical location and production methods. In this study, we aimed to use metagenomic analysis of fermented milk by using three different kefir grains (kefir 1, kefir 2, and kefir 3) from different US sources. We analyzed the microbial compositions of the three milk fermentation samples. This study revealed that each sample contains unique and distinct groups of microbes, kefir 1 showed the least diversity, and kefir 3 showed the highest diversity. Kefir 3 is rich in Proteobacteria while kefir 2 is dominated by the Firmicutes. Using bacterial indicator growth analyses carried out by continuous readings from microplate-based bioreactor assays suggested that kefir 2 fermentation filtrate has higher antibacterial property. We have screened 30 purified cultures of kefir 2 sample and isolated two lactic acid bacteria strains with higher antibacterial activities; the two strains were identified as Leuconostoc mesenteroides 28-1 and Lentilactobacillus kefiri 25-2 by 16S genomic PCR with confirmed antibacterial activities of fermentation filtrate after growing under both aerobic and anaerobic conditions.

Viscosity, Total Acid, Protein and Hedonic Level of Kefir Made from Buffalo Milk with Different Concentration of Kefir Grain

This research aims to determine the effect of different kefir grain concentration to viscosity, total acid, protein and hedonic level of buffalo milk kefir and to determine the ideal kefir grain concentration for buffalo milk kefir. The basic ingredients used in this research were buffalo milk and kefir grain. Concentration of kefir grain at 2.5%, 5%, 7.5%, 10% (g/v) was used to measure viscosity, total acid, protein and hedonic level of buffalo milk kefir. Ostwald pipette and pycnometer were used to determine the viscosity, total acid used titration method with NaOH 0.1 N, destruction and distillation methods were used to determine the protein content and the hedonic test were done by 25 panelists. The results show that different levels of kefir grain concentration gave significant effect (p&lt;0.05) on every parameter. Various levels of kefir grain concentration had highly significant effect (p&lt;0.05) on kefir as a product. The conclusions from this study are the more addition of kefir grain, the more viscosity, total acid, and protein content. From the hedonic test gave specific results in sour taste, aroma, texture and overall.

Novel insights into different kefir grains usefulness as valuable multiple starter cultures to achieve bioactive gluten-free sourdoughs

The milk and water kefir grains are often used for fermented beverages' production with technological and functional effects. These complex natural consortia of microorganisms can have promising applications in other fields of food industry. This work aimed to select the most performant artisanal starter culture, between different water (WKG1, WKG2) or milk (MKG) kefir grains, for gluten-free sourdoughs production. The impact of ingredients' combination, sterilization, gelatinization, and type of fermentation (liquid- and solid-state fermentation) on the microbial consortium's biochemical behavior, antifungal, antioxidant, and acidification potential was evaluated. The proposed flow chart involving the individual sterilization of the composite flour from the fermentation medium, respectively the distilled water, and the freeze-dried WKG2 as starter culture revealed that two up to four backsloppings stabilized the microbiome without alterations of the antioxidant and antifungal properties (p > 0.05). Furthermore, the addition of okara in the fermentation substrate had a positive effect on the organic acids' (lactic, acetic, citric, propionic, and butyric) and bioactive compounds' concentration from the sourdough. Using the kefir grains cultures for the diversification of gluten-free functional sourdough breads can be an approachable way to obtain healthy bioingredients for safe bakery products' manufacture, through the natural microbiomes.

Karakteristik Mikrobiologi dan Kimia Susu Kefir dari Susu Biji Lotus (Nolumbo nucifera)

This sudy aims to determine the effect of increasing of the concentration of lotus milk on the chemical and microbiological properties of kefir milk. This research method using a Randomized Block Design (RBD) with different treatment concentration lotus milk with 5 levels of treatment (A0 100 % cow’s milk and 0 % lotus seed milk, A1 75 % cow’s milk and 25 % lotus seed milk, A2 50 % cow’s milk and 50% lotus seed milk, A3 25 % cow’s milk and 75% lotus seed milk, A4 0 % cow’s milk and 100% lotus seed milk) and repeated 3 times. The treatment parameters observed included chemical analysis (total lactic acid, total alcohol an pH) and microbiological analysis (total lactic acid bacteria). The result showed that the addition of the concentration of lotus milk and cow’s milk in making kefir had a significant effect on the value of the degree of acidity, total lactic acid, total alcohol and total lactic acid bacteria. The value of the degree of acidity ranges from (3.57-3.99), the total lactic acid ranges from (0.52-1.04%), the total alcohol ranges from (0.56-1.10%) and the total lactic acid bacteria ranges from (8.52-8.60 Log cfu/ml).