Milk Kefir Research Articles

New Materials from the Integral Milk Kefir Grain Biomass and the Purified Kefiran: The Role of Glycerol Content on the Film’s Properties

Microbial exopolymers are gaining attention as sources for the development of biodegradable materials. Milk kefir, a fermented dairy product produced by a symbiotic community of microorganisms, generates milk kefir grains as a by-product, consisting of the polysaccharide kefiran and proteins. This study develops two materials, one from whole milk kefir grains and another from purified kefiran. Film-forming dispersions were subjected to ultrasonic homogenisation and thermal treatment, yielding homogeneous dispersions. Kefiran dispersion exhibited lower pseudoplastic behaviour and higher viscous consistency, with minimal effects from glycerol. Both films exhibited continuous and homogeneous microstructures, with kefiran films being transparent and milk kefir films displaying a yellowish tint. Analysis revealed that milk kefir films comprised approximately 30% proteins and 70% kefiran. Kefiran films demonstrated stronger interpolymeric interactions, as evidenced using thermogravimetric and mechanical tests. Glycerol increased hydration while decreasing thermal stability, glass transition temperature, elastic modulus, and tensile strength in both films. However, in kefiran films, elongation at the break and water vapour permeability decreased at low glycerol content, followed by an increase at higher plasticiser contents. This suggests an unusual interaction between glycerol and kefiran in the absence of proteins. These findings underscore differences between materials derived from the whole by-product and purified kefiran, offering insights into their potential applications.

Amino Acid Profile of Goat Milk Kefir with Lacticasei bacillus casei AP and Oat Milk during Storage

Background: Accurate and up-to-date information about amino acid profile is crucial in the production and promotion of dairy products and fermented milk because both components contribute to the nutritional and market value of the dairy products. Methods: This study aims to evaluate the amino acid profile of goat milk kefir supplemented with Lacticaseibacillus casei AP, oat milk or both during 14-day storage using the gas chromatography method. Result: The results demonstrated that Lacticaseibacillus casei AP and oat milk incorporated into kefir production significantly affected amino acids (aspartac acid, glutamic acid, tyrosine, valin, phenylalanine, ileusin and leucine).The dominant amino acids in the treatments were phenylalanine (46.66 ppm), glutamic acid (40.40 ppm) and lysine (23.91 ppm). The storage time only significantly reduced the amount of valine. Conclusively, incorporating Lacticaseibacillus casei AP, oat milk or both into goat milk kefir did not negatively affect the amino acid profile during storage time.

Mushroom and Kefir Functional Characterizations: Hypolipidemia and Gut Microbiota Modulations in Rat Models

ABSTRACTHyperlipidemia is a malnutrition disease associated with different lifestyle factors mainly high fat/cholesterol foods consumption and less physical activity. Consumption of high fiber foods (prebiotic sources) additionally to gut microbiota (GM; probiotics species) could overcome hyperlipidemia and its associated risks. Prebiotics and probiotics are known by protective effects in different diseases like diabetes, inflammatory bowel diseases, and cardiovascular diseases. Mushroom and kefir milk (KM) are known for their high pre/probiotic nutritional values depending on many factors, for example, eating levels and/or conditions. Therefore, this study aimed to measure the potential health benefits of dried powdered mushrooms (DPM) supplemented with KM between hyperlipidemia rats in association with lipid profile, atherogenic index (AI), and GM profile. Rats were randomly divided into main negative control healthy group (G1; −ve), positive control hyperlipidemia (G2; +ve) and three hyperlipidemia groups (G3:G5) fed DPM at 2.5%, 5%, and 10% of rats' diet additionally to 5% KM (DPM + 5% KM) each, respectively. The collected blood samples used for glucose, lipid profile (cholesterol, triglycerides, high‐density lipoprotein cholesterol, and low‐density lipoprotein cholesterol), and AI in addition to fecal sample for GM and short‐chain fatty acids (SCFAs). Collected data illustrated that body weight, blood glucose, lipid profile, GM (Bifidobacteria and Lactobacillus vs. Clostridium histolyticum), AI, and SCFAs were improved between hyperlipidemia fed 5% both PDM + KM (p ≤ 0.05) at the best levels. In conclusion, same DPM/KM levels have broad development as functional active foods that could lower hyperlipidemia incidence and promotes intestinal health; however, much more human studies are needed.

Synergising tradition and innovation: Fortification of milk kefir with date syrup, a novel functional beverage

AbstractMilk kefir is gaining popularity due to its high probiotic content. This study focuses on fortifying milk kefir with date syrup to enhance its sensory attributes, with the goal of encouraging consumption among the younger generation. Date syrup was added to milk kefir in specific proportions (2, 4, 6, 8, and 10% per 100 mL of milk). The selection of the most suitable percentage (10%, 74 °Bx) was determined based on sensory preferences indicated by the panellists. The newly developed fermented beverage underwent physicochemical and biochemical analyses over a 14-day fermentation period. Results revealed that the addition of date syrup led to a significant (P ≤ 0.001) decrease in pH and total soluble solids (TSS) content, accompanied by a noteworthy increase in total phenolic, flavonoids, condensed tannins contents and antioxidant activity (almost 2-fold). Liquid chromatography - heated electrospray ionisation - mass spectrometry (LC-HESI-MS/MS) results identified the presence of a newly formed and important antifungal compound, p-hydroxyphenyllactic acid (HPLA), showing a progressive increase in quantity during the fermentation process (13.8-fold on the 14th day of fermentation). Hence, the outcomes of this study offer compelling evidence that a novel category of functional beverage can be developed by employing milk kefir as an appropriate starter with the incorporation of date syrup.

Application of whey protein microparticulates in the production of ice cream and other dairy products

The aim of this paper is to systemize data on the use of whey protein microparticulates (WPMP) in production of ice cream and other dairy products. Information about the essence of the microparticulation process and methods for WPMP production is given. Data on the composition and physico-chemical properties of liquid and dry WPMP are presented. An effect of sizes of WPMP particles on quality characteristics of products made with their use is described. The majority of the analyzed studies indicate that the diameter of particles is 1.0–2.5 µm. However, contradictory data were obtained for this indicator — if the results of all studies are taken into consideration, a size of conglomerates can be 0.5 to 12 µm. These sizes are comparable with parameters of fat globules, which allow receptors of the human oral cavity to perceive them identically. Due to this, WPMP can be used as an imitator of milk fat. It is noted that the microparticulation process enables producing WPMP with targeted functional properties, namely, with particular characteristics by indicators “solubility”, “water holding capacity”, “gel formation”, “emulsifying and foam forming properties”. Information about the specific features of using and dosing WPMP in fermented milk products, such yogurt, kefir, curd cheese and cheese, is given. A special attention is paid to the results of the investigation of using WPMP in ice cream. It is noted that most often scientists used WPMP to make up for the sensation of fatness in defatted and nonfat dairy products. The ability of WPMP to increase the biological value of food products is highlighted. It has been concluded that WPMP enables formation of soft and elastic structure in low-fat dairy products, intensification of milky color and restriction of ice crystal growth in frozen desserts by binding and equally distributing moisture. The data were obtained about the clinical investigation of an effect of ice cream with WPMP on the health of children and adults. The negative effect of WPMP on the indicators of clinical analyses of humans and their health was not revealed.

Impact of Lyophilized Milk Kefir-Based Self-Nanoemulsifying System on Cognitive Enhancement via the Microbiota-Gut-Brain Axis.

Chronic inflammatory bowel disorders (IBDs) are characterized by altered intestinal permeability, prompting inflammatory, oxidative stress, and immunological factors. Gut microbiota disorders impact brain function via the bidirectional gut-brain axis, influencing behavior through inflammatory cascades, oxidative stress, and neurotransmitter levels. This study highlights the potential effect of integrating lyophilized milk kefir alone and lyophilized milk kefir as solid carriers loaded with a self-nanoemulsifying self-nanosuspension (SNESNS) of licorice extract on an induced chronic IBD-like model in rats. Licorice-SNESNS was prepared by the homogenization of 30 mg of licorice extract in 1 g of the selected SNEDDS (30% Caraway oil, 60% Tween 20, and 10% propylene glycol (w/w)). Licorice-SNESNS was mixed with milk kefir and then freeze-dried. Dynamic TEM images and the bimodal particle size curve confirmed the formation of the biphasic nanosystems after dilution (nanoemulsion and nanosuspension). Daily oral administration of lyophilized milk kefir (100 mg/kg) loaded with SNESNS (10 mg/kg Caraway oil and 1 mg/kg licorice) restored normal body weight and intestinal mucosa while significantly reducing submucosal inflammatory cell infiltration in induced rats. Importantly, this treatment demonstrated superior efficacy compared to lyophilized milk kefir alone by leading to a more significant alleviation of neurotransmitter levels and improved memory functions, thereby addressing gut-brain axis disorders. Additionally, it normalized fecal microbiome constituents, inflammatory cytokine levels, and oxidative stress in examined tissues and serum. Moreover, daily administration of kefir-loaded SNESNS normalized the disease activity index, alleviated histopathological changes induced by IBD induction, and partially restored the normal gut microbiota. These alterations are associated with improved cognitive functions, attributed to the maintenance of normal neurotransmitter levels and the alleviation of triggered inflammatory factors and oxidative stress levels.

Chemical Composition and Sensory Characteristics of Skimmed Milk Kefir Sensory on Variation of Concentration of Light Coconut Extract (Cocos Nucifera L.)

Kefir is a fermented milk product that is processed through fermentation of kefir granules. The objectives of this study are: 1. To analyse the effect of young coconut extract concentration on total microbes, ethanol and pH value of skimmed milk kefir. 2. To analyse the sensory test results of skimmed milk kefir with young coconut extract concentration. The method used in this research is Completely Randomised Design (CRD) with the treatment of variations in the percentage of skimmed milk and young coconut extract, namely: 100% skimmed milk: 0% young coconut extract; 95% skimmed milk: 5% young coconut extract; 90% skimmed milk: 10% young coconut extract; 85% skimmed milk: 15% young coconut extract; 80% skimmed milk: 20% young coconut extract with 3 repetitions and obtained 15 experimental units. The data obtained were analysed by ANOVA (Analysis of Variant). The results showed that increasing the concentration of young coconut extract increased the total number of microbes. Total microbes ranged from 1.48 x 10⁸ to 2.17 x 10¹⁰. Increasing the extract concentration from 15% to 20% increased the alcohol content from 0.07% to 0.20. Increasing the concentration of young coconut extract also significantly decreased the pH value of kefir after fermentation, with the lowest pH value (3.18) at 20% concentration. The concentration of young coconut extract in skimmed milk kefir significantly affected colour, texture and taste.

Daily Intake of Household-Produced Milk Kefir on Salmonella Typhimurium Infection in C57BL/6 Mice: Mortality, Microbiota Modulation and Immunological Implications.

Salmonellosis, a major global cause of diarrheal diseases, significantly impacts the intestinal microbiome. Probiotic-rich beverages, such as kefir, are increasingly utilized as alternative health-promoting beverages associated with various microbiota benefits. This study investigated the repercussions of daily consumption of household-produced milk kefir on Salmonella enterica serovar Typhimurium infection in C57BL-6 mice. Kefir consumption pre infection reduced the presence of inflammatory cells in the colon and altered the cytokine profile by reducing IL-10 and increasing IFN-γ. Despite reducing intestinal inflammation, kefir intake did not yield a prompt response to an acute infection caused by the aggressive pathogen Salmonella. This contributed to increased mortality in the mice, evidenced by higher fecal Salmonella counts post-infection. Metabarcoding analysis demonstrated that the use of kefir before infection increases butyric acid by the higher abundance of Lachnospiraceae and Prevotellaceae families and genus in feces, coupled with an increase in Muribaculaceae family and Bacteroides genus among infected kefir-treated mice. While kefir hinted at microbiota alterations reducing enterobacteria (Helicobacter), decrease IL-10, and increased IFN-γ, butyric acid on pre-infection, the beverage potentially facilitated the systemic translocation of pathogens, intensifying the infection's severity by altering the immune response. The use of kefir in the dosage of 10% w/v (109 CFU), for acute infections with Salmonella Typhimurium, may not be enough to combat the infection and worsen the prognosis, leaving the intestine less inflamed, favoring the replication and translocation of the pathogen. These findings underscore the importance of prudently evaluating the widespread use of probiotics and probiotic-rich beverages, especially during acute infections, given their potential association with adverse effects during these diseases.

Characterization of milk and water-based kefir microbiota

The production of functional foods is expanding and requiring research results in the areas of food, health, chemistry, pharmaceuticals, etc. Within this context, the inclusion of kefir in the diet has been gaining ground, as it meets the requirements of a functional food. Kefir can be defined as a fermented, acidic milk with a low alcohol content and produced from grains that contain microorganisms that carry out the fermentation process. Kefir can be produced using various means, such as milk or water-based substrates. In both process, the production is very similar. Kefir is composed of microorganisms such as bacteria and yeasts that are often welcomed by the population as a probiotic source and are regularly used in the production of food and/or medicine by the industry. To produce water kefir, sucrose is used, and the process is carried out at temperatures ranging from 20℃ to 25℃, with an incubation time between 12 and 72 hours in this context. The objective of this work was to present a literature review on the characterization of milk and water-based kefir.

Utilisation of agricultural residues for antioxidant exopolysaccharide production by Bacillus spp.

This study tested the antioxidant activities of exopolysaccharides (EPSs) produced by eight Bacillus spp. from Thai milk kefir utilising four agricultural by-products in Thailand; copra meal, mangosteen peel, sorghum, and para rubber sawdust as carbon sources. Sorghum showed the highest starch and sugar content of 73.33% while copra meal showed the lowest (13.08%). B. tequilensis PS21 produced the highest dry weight EPS, followed by B. amyloliquefaciens KW1 and B. tequilensis PS22 from four substrates. B. tequilensis PS21 generated the most EPS with sorghum (0.75 ± 0.09 g DW/100 mL culture), followed by mangosteen peel (0.61 ± 0.07 g). EPS from B. amyloliquefaciens KW1 using copra meal displayed the highest DPPH radical scavenging activity of 33.39 ± 1.34% and EPS from the same bacteria using sorghum displayed the highest hydroxyl radical scavenging activity of 49.78 ± 0.86%. This approach demonstrated a bio-circular green economy paradigm in converting agricultural biowastes into valuable EPS biomaterials with potential applications.

Kajian pengembangan agrotechnopreneurship berbasis potensi sektor pertanian di Kabupaten Jember

Jember Regency is an agricultural area in East Java Province that produces various agricultural commodities that can be used as a base in developing agrotechnopreneurship activities. In general, this research aims to analyze the potential for agrotechnopreneurship development based on the potential of the agricultural sector in Jember Regency, including subsectors of food crops, horticulture, plantations, fisheries, and livestock. The aspects studied in detail include identifying agrotechnopreneurship products that have the potential to be developed in Jember Regency, determining potential agrotechnopreneurship products in each agricultural subsector, calculating the added value obtained, and estimating market opportunities for potential agrotechnopreneurship products. There are several methods used in this research, including descriptive methods for the identification of agrotechnopreneurship products, the MPE method to determine potential agrotechnopreneurship products, the Hayami method to calculate the added value of potential agrotechnopreneurship products, and Least Square method to calculate the estimated amount of market demand for potential agrotechnopreneurship products. The results showed that the number of agrotechnopreneurship products identified was recorded at 93 products, including products from the food crop subsector (23 products), horticulture subsector (28 products), plantation subsector (17 products), livestock subsector (5 products), and fishery subsector (20 products). Agrotechnopreneurship products selected as potential products include mocaf flour (food crops), chili sauce (horticulture), coconut briquettes (plantation), cow's milk kefir (livestock), and shredded catfish (fishery). Agrotechnopreneurship products that have the highest added value are coconut briquettes (49%) and shredded catfish (45%), followed by cow's milk kefir (39%), mocaf (18%), and chili sauce (10%). The results of the market potential analysis show that the potential agrotechnopreneurship products analyzed have good market prospects and tend to increase market demand.

Comparison of Fermentation Kinetics of Milk Kefir and White Rice Kefir at Low Temperatures: Exploring the Effects on Product Quality

Kefir fermentation has been extensively studied because of its potential to develop novel functional drinks and its various biological activity. This study investigates the comparative fermentation kinetics of milk kefir and white rice kefir at low temperatures, addressing a gap in current research. Utilizing a comprehensive research methodology, including sample preparation, fermentation processes, and various analyses, the study explores the distinct patterns observed in the fermentation kinetics, physicochemical properties, and microbiological characteristics of both kefir types. The results highlight significant differences influenced by low temperatures, emphasizing the need to consider specific attributes for each kefir type in low-temperature fermentation. The findings contribute novel insights into optimizing fermentation conditions and enhancing product quality. The results offer additional perspectives on the influence of fermentation temperature on microbial dynamics, physicochemical properties, and health-related aspects in various fermented products. This study advances our understanding of kefir fermentation, providing valuable implications for the production of high-quality and functional beverages.

Combined Metabolomic and NIRS Analyses Reveal Biochemical and Metabolite Changes in Goat Milk Kefir under Different Heat Treatments and Fermentation Times.

Dairy products are an important source of protein and other nutrients in the Mediterranean diet. In these countries, the most common sources of milk for producing dairy products are cow, goat, sheep, and buffalo. Andalusia is traditionally the largest producer of goat milk in Spain. Kefir is a fermented product made from bacteria and yeasts and has health benefits beyond its nutritional properties. There is a lack of knowledge about the molecular mechanisms and metabolites that bring about these benefits. In this work, the combination of analytical techniques (GC-FID, UHPLC-MS-QToF, GC-QqQ-MS, and GC-ToF-MS) resulted in the detection of 105 metabolites in kefir produced with goat milk from two different thermal treatments (raw and pasteurized) fermented at four time points (12, 24, 36, and 48 h, using 0 h as the control). Of these, 27 metabolites differed between kefir produced with raw and pasteurized milk. These changes could possibly be caused by the effect of pasteurization on the microbial population in the starting milk. Some interesting molecules were identified, such as shikimic acid, dehydroabietic acid, GABA, and tyramine, which could be related to antibacterial properties, strengthening of the immune system, and arterial pressure. Moreover, a viability assay of the NIRS technique was performed to evaluate its use in monitoring the fermentation and classification of samples, which resulted in a 90% accuracy in comparison to correctly classified samples according to their fermentation time. This study represents the most comprehensive metabolomic analysis of goat milk kefir so far, revealing the intricate changes in metabolites during fermentation and the impact of milk treatment.

Main Composition and Visual Appearance of Milk Kefir Beverages Obtained from Four Consecutive 24- and 48-h Batch Subcultures

Nowadays, there has been a significant rise in the consumption of kefir, a functional beverage touted for its perceived health benefits. To offer a high-quality beverage to consumers, it is imperative to scrutinize and fine-tune the fermentation process. This study seeks to investigate the impact of fermentation time and the number of subcultures on the physicochemical, microbiological, and volatile composition, as well as the visual appearance, of kefir beverages obtained from four consecutive 24- or 48-h batch subcultures. All fermented beverages exhibited low lactose, ethanol and acids levels, with counts of viable probiotic lactic acid bacteria and yeast exceeding 106 colony forming units/mL. The four kefir beverages from the 48-h batch subcultures notably showed the lowest total concentrations of volatile compounds, likely due to overfermentation and over-acidification of the beverages. This caused the separation of the whey and curd, along with the formation of large gas bubbles, negatively affecting the visual appearance of the products. These findings emphasize the importance of fine-tuning the fermentation process to ensure the production of high-quality kefir beverages that align with consumer preferences. The four beverages from the 24-h batch subcultures exhibited high microbiological and physicochemical stability during storage at 4 °C for 28 days.

Evaluation of the Efficacy of Targeted Microbiome Therapy in Non-Alcoholic Steatohepatitis Rat Model

Abstract Non-alcoholic steatohepatitis (NASH) is the clinically aggressive variant of non-alcoholic fatty liver disease. Hippo pathway dysregulation can contribute to NASH development and progression. The use of probiotics is effective in NASH management. Our aim is to investigate the efficacy of kefir Milk in NASH management via modulation of hepatic mRNA-miRNA based panel linked to NAFLD/NASH Hippo signaling and gut microbita regulated genes which was identified using bioinformatics tools. Firstly, we analyzed mRNAs (SOX11, SMAD4 and AMOTL2), and their epigenetic regulator (miR-6807) followed by validation of target effector proteins (TGFB1, IL6 and HepPar1). Molecular, biochemical, and histopathological, analyses were used to evaluate the effects of kefir on high sucrose high fat (HSHF) diet -induced NASH in rats. We found that administration of Kefir proved to prevent steatosis and development of the inflammatory component of NASH. Moreover, Kefir improved liver function and lipid panel. At the molecular level, kefir down-regulated the expression of miR 6807-5p with subsequent increase in the expression of SOX 11, AMOTL2 associated with downregulated SMAD4, resulting in reduction in the expression of the inflammatory and fibrotic markers, IL6 and TGF-β1 in the treated and prophylactic groups compared to the untreated rats. In conclusion, Kefir suppressed NASH progression and improved both fibrosis and hepatic inflammation. The produced effect was correlated with modulation of SOX11, SMAD4 and AMOTL2 mRNAs) – (miR-6807-5p) – (TGFB, IL6 and, HepPar1) expression.

Evaluating the potential effect of microalgae on soymilk vegan kefir in terms of physical, chemical, microbiological properties

The demand for functional fermented plant-based milk products has intensively increased. Here, the physical, biochemical and microbial consortia of two different kefir samples which are soymilk kefir (S) and cows' milk kefir (M) was evaluated and examination of nutritional and microbial value of adding Haematococcus pluvialis microalgae to soymilk kefir at a ratio of 0.25 % (S1) and 0.50 % (S2) was done in order to fulfill deficiencies caused by the lack of animal-based milk. As part of a functional comparison between the two samples, besides physicochemical and biochemical analysis, the structure and functional diversity of the bacterial communities was also evaluated by metagenomic analysis. S1 and S2 kefir samples presented significantly increased pH, protein, fatty acid index and decreased fat content than the M sample. It was also observed a high bacterial diversity in S1 and S2 kefir samples including greater abundance of Leuconostoc lactis (31.98 %), Lactococcus lactis (23.68 %), Leuconostoc mesenteroides (19.72 %); Liquorilactobacillus nagelii (32.70 %). Moreover, the increased concentration of H. pluvialis in S1 and S2 kefirs resulted in reduction of the abundance of Bacillus cereus. It can be concluded that microalgae biomass can be used as an innovative natural ingredient to develop fermented, functional, vegan and lactose-free kefir with high nutritional and bio-diversified options.

Evaluation of butterfly pea powder addition to cow’s milk kefir on the antibacterial activity against bacteria causing foodborne disease

Abstract Foodborne diseases are caused by consuming food contaminated with pathogens such as bacteria, viruses, parasites, or toxic chemicals, as well as biotoxins. Bacteria responsible for foodborne disease include Escherichia coli and Staphylococcus aureus. The typical approach to managing foodborne disease involves the use of antibiotics, which might lead to resistance over time. Kefir is a probiotic drink that can help maintain health by balancing the natural gut microflora. This study aims to investigate the impact of adding butterfly pea powder to kefir on its antibacterial activity against the bacteria that cause foodborne disease. Kefir was prepared by adding butterfly pea powder in six different concentrations (0%, 0.5%, 1%, 1.5%, 2%, and 2.5%) with four replications. Kefir’s pH, total titrated acid, total LAB, and its antibacterial activity using the microdilution method were observed. The results revealed that the addition of butterfly pea flower powder at various concentrations significantly influenced the pH value, total acidity, and antibacterial effects against E.coli and S.aureus but did not significantly affect the total LAB count. Butterfly pea flower powder reduced the pH value, increased the total acidity, and enhanced the antibacterial activity, resulting in a higher percentage of inhibition against the tested bacteria without adversely affecting LAB growth. It was concluded that adding butterfly pea powder to cow milk kefir potentially improves the antibacterial functions against bacteria causing foodborne disease.

Comparing Nutritional Values and Bioactivity of Kefir from Different Types of Animal Milk.

The growing interest in fermented dairy products is due to their health-promoting properties. The use of milk kefir grains as a starter culture made it possible to obtain a product with a better nutritional and biological profile depending on the type of milk. Cow, buffalo, camel, donkey, goat, and sheep milk kefirs were prepared, and the changes in sugar, protein, and phenol content, fatty acid composition, including conjugated linoleic acids (CLAs), as well as antioxidant activity, determined by ABTS and FRAP assays, were evaluated and compared. The protein content of cow, buffalo, donkey, and sheep milk increased after 24 h of fermentation. The fatty acid profile showed a better concentration of saturated and unsaturated lipids in all fermented milks, except buffalo milk. The highest content of beneficial fatty acids, such as oleic, linoleic, and C18:2 conjugated linoleic acid, was found in the cow and sheep samples. All samples showed a better antioxidant capacity, goat milk having the highest value, with no correlation to the total phenolic content, which was highest in the buffalo sample (260.40 ± 5.50 μg GAE/mL). These findings suggested that microorganisms living symbiotically in kefir grains utilize nutrients from different types of milk with varying efficiency.

Evaluation of the probiotic, technological, safety attributes, and GABA-producing capacity of microorganisms isolated from Iranian milk kefir beverages.

Kefir beverage has beneficial microorganisms that have health-giving properties; therefore, they have a good potential to be probiotic. This study evaluated the probiotic potential, technological, and safety characteristics of Enterococcus faecalis, Lactococcus lactis, and Pichia fermentans isolated from traditional kefir beverages. First, isolates were evaluated in terms of resistance to acid, alkali, bile salts, trypsin, and pepsin of the gastrointestinal tract. The auto-aggregation and co-aggregation ability of isolates were measured using spectrophotometry. Antimicrobial activities were assayed against important food-borne pathogens using the agar well diffusion method. Moreover, gamma-aminobutyric acid (GABA) production was investigated by thin-layer chromatography (TLC). Among the isolates, P. fermentans had an 85% total survival rate, but its amount reached below 6 log CFU/ml which is considered non-resistant, and it showed the highest auto-aggregation (74.67%). Moreover, only L. lactis showed antimicrobial activity and had the highest co-aggregation with E. coli PTCC 1338 (54.33%) and L. monocytogenes ATCC 7644 (78%). Finally, an evaluation of the technological and safety characteristics of the strains showed that the strains produced GABA and were safe. Although the isolates were not resistant to the gastrointestinal tract, their supernatant contained valuable natural compounds, including antioxidants, GABA, and antimicrobials, which can be used to produce functional foods and medicines. In addition, other approaches, such as increasing the initial number of strains, using foods as carriers of isolates, and encapsulating the isolates, can effectively increase the survivability of isolates in the gastrointestinal tract.

The effect of skim milk powder on physical, chemical, and microbiology characteristics of goat milk kefir powder

This research was to determine the effect of skim milk powder fillers on the physical, chemical, and microbiology of goat's milk kefir powder. The benefit obtained from this research is that it can increase the diversification of fermented milk products that have a long shelf life. This research used a Completely Randomized Design (CRD) with 5 treatments and 4 replications. The treatments were P1: Addition of 0% (w/v) powder skim milk filler, P2: Addition of 2.5% (w/v) powder skim milk filler, P3: Addition of 5% (w/v) powder skim milk filler, P4: Addition of 7.5% (w/v) powder skim milk filler and P5: Addition of 10% (w/v) powder skim milk filler. The results showed that the addition of skim milk fillers has a significant effect (P<0.05) on yield, solubility, total dissolved solids, total acid, pH value, water content, fat carbohydrate content, and microbiological quality which has no significant effect (P>0.05) on viscosity, protein content and ash content. The conclusion that can be obtained is the addition of 2.5% skim milk filler is the best treatment.