Fermented Milk Products Research Articles

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.

Evaluation of MENAQUINONE‐7 and fat‐soluble vitamin production by starter cultures during fermentation in dairy products using RPLC method

AbstractVitamin K2, also known as menaquinone, has become a significant research focus, particularly in fermented products. This study aims to investigate the content of menaquinone‐7 (MK‐7), an essential form of vitamin K, and other fat‐soluble vitamins (A, D, E) during the fermentation of various fermented milk products. The vitamin contents of six fermented milk products were analyzed: two yogurt samples (produced with commercial starter and probiotic starter), two kefir samples (produced with commercial starter and kefir grain), and milk fermented with Lactobacillus acidophilus or Bifidobacterium bifidum. Throughout the fermentation process, continuous pH monitoring was conducted, and fermentation was terminated based on pH levels. Fat‐soluble vitamins and vitamins K1, K2 were extracted from samples taken at specific fermentation periods and quantitatively determined using the reverse phase liquid chromatography (RPLC) method. The developed method was validated according to ICH guidelines. Simultaneously, the microbial content of the samples was analyzed. Among the fermented dairy products analyzed, the highest MK‐7 content (4.82 μg/100 g) was found in the kefir sample produced with kefir grain (KG). The diverse microorganisms in kefir grains necessitated detailed research to explain their role in this complex mechanism. In yogurt samples, the presence of L. acidophilus in the YB sample suggests that this bacterium may be responsible for the observed differences. This is supported by the LA sample, where production with L. acidophilus strain showed an increase from 0.97 to 1.70 at the 20th hour of fermentation. It was noted that the concentration of menaquinone‐7 increased throughout the fermentation period. Given the critical health effects of essential fat‐soluble vitamins and MKs, determining their content in commonly consumed fermented dairy products and understanding the influence of starter cultures, which are potential probiotics, on vitamin production underscores the importance of this research. It is important to highlight the potential of fermented products in nutritional recommendations.

Milk production and viability of the various smallholder dairying models used in Zimbabwe.

An evaluation of milk yield, dairy products and viability of the smallholder dairy production models used in Zimbabwe was carried out. We used secondary data on 1167 smallholder dairy farmers. These were categorised into commercial dairying (119), Milk collection centre (MCC) bulking and processing (145), MCC bulking and delivering to processor (87), farm gate (468) and other (348) models. Data were analysed using SPSS version 25.0. The average daily milk yield per cows was highest in the Commercial dairying model (9.20 ± 0.4l) but was not significantly different from the MCC bulking and processing and MCC bulking and delivering to processor models. Average lactation milk yield per cow was highest (P < 0.05) in the commercial dairying model (2804.91 ± 133.9l) and was significantly different from the rest of the models. The processed milk products identified in the study were fermented milk, pasteurised milk and unspecified products but production volumes were very low in the respective models. There were no differences (P > 0.05) in gross margin across all the smallholder dairying models. The commercial dairying model surpassed all models on proportion of pure exotic dairy breeds, number of milking cows, milk yield. However, it was discovered that all models were underperforming but smallholder dairy farmers can be recommended to adopt the commercial dairying model if measures to improve milk yield per cow and reduce milk production costs are established.

Qualitative indicators of milk and fermented milk products when activated zeolite and probiotics are included in the diet of cows

Relevance. The quality of milk depends on the season of the year, the breed of animals, the state of metabolism, and the characteristics of feeding and maintenance technology. The quality of milk determines its technological properties and the quality of its processed products.Methods. The content of somatic cells in milk, the acidity of milk, cottage cheese, yogurt, and syneresis of yogurt were determined. In milk processing products, the content of the mass fraction of nitrogen and crude protein, crude ash, calcium, and phosphorus was determined.Results. When feeding cows with the yeast probiotic activated zeolite and the phytoprobiotic “Provitol”, a significant decrease in the content of somatic cells in freshly milked milk of cows was established by 13.02% (p &lt; 0.05). Significantly lower milk acidity values were established (by 6.00% (p &lt; 0.001) and 12.79% (p &lt; 0.001), respectively), significantly higher yogurt acidity values (by 6.00% (p &lt; 0.001) and 12.79% (p &lt; 0.001), respectively, significantly lower yogurt syneresis (by 4.70% (p &lt; 0.001) and 3.10% (p &lt; 0.01), respectively). The use of activated zeolite and yeast probiotic “Kluver Pro” in the diets leads to a significantly higher content (compared with the control) of the mass fraction of fat in cottage cheese and yogurt — by 10.47 abs. % (p &lt; 0.001) and 4.58 abs. % (p &lt; 0.001).

The Impact of Fermented Milk Products Containing Bifidobacterium longum BB536 on the Gut Environment: A Randomized Double-Blind Placebo-Controlled Trial.

Probiotics, particularly those native to the gut microbiota, have a profound influence on the gut environment. In this study, we conducted a randomized placebo-controlled, double-blind, parallel-group comparison trial to investigate the effects of Bifidobacterium longum BB536 (B. longum BB536) on the fecal microbiota and metabolite compositions in healthy individuals. We compared the effects of fermented milk produced solely with Streptococcus thermophiles and Lactobacillus bulgaricus (placebo group) and fermented milk supplemented with B. longum BB536 (BY group). Our findings revealed a significantly greater relative abundance of Faecalibacterium in the BY group than in the placebo group by the 3rd day, a trend that persisted until the end of the trial on the 17th day. Additionally, the BY group presented significantly increased concentrations of tryptophan (Trp), Indole-3-lactic acid, and Indole-3-aldehyde on the 17th day. A significant positive correlation was observed between the relative abundance of Faecalibacterium and the number of viable B. longum BB536 bacteria in the feces. The concentrations of Trp and Indole-3-acetic acid were also significantly correlated with the number of viable B. longum BB536 bacteria in the feces. Our results suggest that B. longum BB536 intake can modulate the gut microbiota and metabolite profiles, which are general indicators for monitoring the gut environment, potentially conferring health benefits to the host.

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.

Viability of Lactobacillus acidophilus in acidophilus milk during frozen storage and its potential to lower cholesterol: an In vivo study.

The viability and functional activity of lactic acid bacteria (LAB), such as Lactobacillus acidophilus in a fermented milk product is important. One of the functional activities of the LAB in fermented milk is the ability of the LAB to positively impact the human health. This study aimed to determine the effect of frozen storage on the fermented milk, namely acidophilus milk, based on the nutritional milk quality, the viability of L. acidophilus, and its potential to lower cholesterol levels in Wistar rats. The parameters measured was including milk quality (mainly pH, protein content, lactic acid levels, and syneresis), L. acidophilus bacterial viability in frozen storage (for 1, 2, and 3months), and some biological assays to evaluate the potential of milk in lowering blood cholesterol levels in Wistar rats. The result of this study suggests that acidophilus milk quality can be maintained in frozen storage for two months, and it had lactic acid levels of 1.07%, pH of 4.08, and protein levels of 3.33%. Giving acidophilus milk to Wistar rats for 15days could reduce the cholesterol level continuously until 30days of treatment. Therefore, this study proves that acidophilus milk quality can be maintained very well in frozen storage, and its functional properties to lower the cholesterol level of Wistar rats can be achieved after two weeks of consumption.

Ameliorated Viability of Lactic Acid Bacteria in Fruit Juice Isolated from Indigenous Dahi with Prebiotics (Asparagus falcatus and Zingiber officinale)

Dahi is a fermented milk product containing probiotic lactic acid bacteria. This study aimed to isolate, identify, and characterize lactic acid-producing bacteria from native Dahi and evaluate their viability in orange juice using natural prebiotics. Dahi samples were obtained from local shops in Chattogram and Bogura, Bangladesh. Lactic acid-producing bacteria were isolated using MRS (de Mann Rogosa and Sharpe) medium. The isolated bacteria were identified through colony morphology, biochemical tests, and probiotic characteristics. Molecular identification was performed using polymerase chain reaction (PCR) targeting conserved 16S rDNA regions. Isolates of the genus Lactobacillus and Lactococcus lactis sp. Lactis were confirmed and used to develop probiotic orange juice. Prebiotics (Asparagus falcatus and Zingiber officinale) were added to the juice to support probiotic growth. The inoculated cell’s viability and the juice’s physicochemical parameters were evaluated during fermentation (48 hours) and storage (28 days). All fruit juice samples showed a mean number of viable cells of at least 1×105 CFU/mL during the 48-hour fermentation and 28-day storage in the refrigerator. Using natural prebiotics positively affected the survival of lactic acid bacteria, as demonstrated by bacterial colony growth on Petri dishes. Developing probiotic fruit juice enriched with prebiotics could be an effective alternative for individuals allergic or intolerant to milk-based products. Incorporating lactic acid bacteria from native Dahi into orange juice, combined with natural prebiotics, resulted in viable probiotic cells throughout fermentation and storage.

Impact of pre-exposure stress on the growth and viability of Lactobacillus acidophilus in regular, buriti pulp and orange byproduct fermented milk products

The loss of probiotics viability in yogurts and fermented milk is a significant challenge in producing yogurt and fermented milk. Thus, pre-exposure of probiotics to stress conditions can be a viable alternative to increase the probiotic viability. Moreover, the use of fruit pulp and agro-industrial residues in these products has demonstrated promising results in promoting growth and improving the viability of probiotics. Thus, this study aimed to evaluate the effects of pre-exposure to acid, oxidative and osmotic stress on the growth and viability of Lactobacillus acidophilus in yogurts and naturally fermented milk containing buriti (Mauritia flexuosa Mart.) pulp or orange byproduct. L. acidophilus was individually pre-exposed to acid, oxidative, and osmotic stress and used in the production of yogurts and fermented milk to determine both the acidification profile and growth of the cultures. Furthermore, during cold storage, the post-acidification profiles and viability of microbial cultures added to the yogurts and fermented milk were monitored. Results showed that pre-exposure to stress conditions influenced the growth parameters as the growth rate (μ) and lag phase (λ) of L. acidophilus and the starter cultures of S. thermophilus and L. delbrueckii subsp. bulgaricus. Moreover, an increase in the viability of L. acidophilus - pre-exposed to acid stress - was observed on the 21st day of storage of natural yogurts containing orange byproduct compared with non-stressful conditions. This study reports new data on the growth of probiotic cultures pre-exposed to stress conditions in products added of pulps and agro-industrial residues, which have not yet been shown in the literature.

Use of plant raw materials in the production of dairy products

Abstract Today, the development of the food industry is aimed at creating balanced products that have beneficial properties for the human body in the long term. As one of these approaches, the use of sprouted plant raw materials (barley grains) in fermented milk products – yoghurts – can be proposed. The proposed plant raw materials have a number of useful properties: total antioxidant activity (136 ± 4) DPPH%, flavonoid content (96 ± 5) %, polyphenols (125 ± 4) %, and also contains a large amount of dietary fiber and minerals. The most effective way is to add the vegetable raw ingredient after the fermentation process and the formation of a product clot. The addition of the plant ingredient was carried out in quantities of 1, 2 and 3%. A direct relationship was noted between the amount of added additive and the degree of syneresis; application in larger quantities partially worsens the syneresis properties of the fermented milk product, and the viscosity of yogurt also slightly decreases. At the same time, a positive effect on the development of microflora of fermented milk products was noted, the presence of Streptococcus thermophilus in the form of mono-, diplo- and streptococcal forms was revealed.

Objectives for the use of raw materials and component composition for the production of low-lactose ice cream from goat milk

A huge number of people all over the world suffer from lactose intolerance. The second problem is an allergy to cow milk protein. People with lactose intolerance, as well as those who suffer from cow milk allergies, are forced to significantly limit their choice of ice cream or give it up completely. The article describes a solution to the problem of eating ice cream by children and adults suffering from lactose intolerance and an allergy to cow milk protein, and presents ways to overcome it.The goal of the research. Objectives for the use of raw materials and component composition for the production of low-lactose ice cream from goat milk. During the research, the quality indicators of the selected raw materials have been studied, the characteristics of the main ingredients for the production of low-lactose ice cream have been substantiated and given. Goat milk, in terms of its quality indicators, is most suitable for the production of ice cream, because it contains more protein, fat, solids, less lactose and does not cause allergies, and therefore it has been chosen as the main raw material for the production of ice cream. A theoretical and practical analysis of the chemical composition and properties of goat milk has been carried out, and compared with cow. To reduce the lactose content, a dual method of lactose hydrolysis has been chosen - the use of probiotic starter cultures and the lactase enzyme. In the process of combined hydrolysis at a temperature of 37-39⁰ C for 4-6 hours, a reduction in lactose content of less than 0.9% is achieved, while the concentration of cells of probiotic microorganisms in active form reaches 108 CFU/cm3. It is proposed to use the “Lactomix KM” stabilization system, which is usually used in the production of fermented milk products.

Assessment of the Biological Activity of a Probiotic Fermented Milk Product with the Addition of Lactobacillus helveticus Cell-Free Supernatant

Products enriched with probiotic microorganisms have proven to possess immunomodulatory, antioxidant, hypo-cholesterolemic, hypotensive, and antimicrobial properties. Biologically active substances, which are by-products of microbial fermentation, have potential applications in various industries. Cell-free supernatants, depending on the microorganisms used and production conditions, can exhibit antimicrobial, antioxidant, bifidogenic, and other biological activities. This paper presents a study on the biological activity of a probiotic fermented milk product, supplemented with 0.01% lyophilized cell-free supernatant from Lactobacillus helveticus. The fermented milk product was developed based on a composition of Lacticaseibacillus rhamnosus F, Lactococcus cremoris CR201, and Propionibacterium shermanii E2. The research evaluated antimicrobial activity, Bifidobacteria growth stimulation, and the content of organic acids, amino acids, and B vitamins. It was found that adding lyophilized cell-free supernatant to the fermented milk product enhanced its biological activity. In particular, the experimental samples showed a threefold increase in vitamin B6 content compared to the control, reaching 22.412 μg/100 g. Additionally, the amino acid content in the experimental samples exhibited a significant increase of more than 100% in the essential amino acid tryptophan compared to the control. Notably, antimicrobial activity increased against several opportunistic strains. The experimental samples also showed a significant increase in lactic and formic acids, which may enhance the product’s inhibitory properties against pathogens. An increase in antioxidant activity was observed, potentially due to the higher content of tryptophan and vitamin B6. The positive effect of adding cell-free supernatant on the growth of Bifidobacteria was also demonstrated. Thus, the findings suggest that this cell-free supernatant can be recommended as an additive in the production of fermented milk products, food additives, dietary supplements, and animal feed.

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.

Characterization of wild lactic acid bacteria for industrial applications

For some decades now, Lactic acid bacteria (LAB) have been an important raw resource in the food and pharmaceutical industries to produce variety of dairy based products including but not limited to cheese, yoghurt, lactic acid. drugs and cosmetics. The LAB strains include the genera of Lactobacillus and Streptococcus. The importation of raw materials such as lactic acid, which can be obtained from indigenous sources, however, affects the foreign exchange of Nigeria's economy greatly. This study was designed to screen, characterize and identify LAB for industrial applications. A total of eighty (80) Lactic Acid Bacteria (LAB) strains were isolated from samples of nunu (a locally fermented milk product) using basic microbiological procedures such as morphological/phenotypic, gram staining, and other biochemical tests. All the isolates were tested for their acidification, curd formation and aroma production abilities. After forty-eight (48) hours of incubation at 420C, twenty-three (23) isolates which satisfied established phenotypic and biochemical criteria were selected for further functional tests. Out of the twenty-three (23) isolates obtained, two (2) strains L53 and L12 had additionally high exopolysaccharide production ability and correspondingly produced yoghurt with high viscosity and very low residual content. Based on the remarkable characteristics obtained from these two species, they are therefore recommended for optimization and proposed for large scale utilization as starter cultures in the dairy industries.

QUALITY AND SAFETY MANAGEMENT OF FERMENTED MILK PRODUCTS FROM CAMEL MILK BASED ON HACCP PRINCIPLES

Currently, the main task of domestic producers of milk and dairy products is to provide consumers with high-quality and safe dairy products. At the same time, the main guarantee of safe production is the introduction of the HACCP system at enterprises.The main advantage of the HACCP system is error detection, namely prevention and prevention, through step-by-step control of the entire food production chain.The research work was carried out on the basis of the national standard SS RK 1179-2003 «Quality systems. Food quality management based on the principles of HACCP. General requirements». At the first stage, the necessary information about the fermented milk product from camel milk was collected (composition, organoleptic characteristics, indicators characterizing quality and safety, application, type of packaging, storage and delivery conditions) and a flowchart of its production process was compiled. At the second stage, the results of scientific research by other authors and regulatory documents related to the quality and safety of camel milk and products from it were examined to analyze chemical, biological and physical risks. Then an assessment of the probability of the identified dangerous risks was carried out. Further, using the Decision Tree tool, critical control points in the technology of the research object were identified, allowing to manage safety and improve quality in their production.

DEVELOPMENT OF A DRYING UNIT FOR THE PRODUCTION OF KURTA

The article is devoted to the development of a drying unit for the production of kurt, a traditional fermented milk product that is very popular in Kazakhstan. Kurt is not only a national product, but also has a high nutritional value, vitamin and mineral content. Regular consumption of kurt helps to restore beneficial intestinal microflora and is especially useful for pregnant women, children and the elderly. The traditional method of drying kurt in the open air has a number of disadvantages, such as dependence on weather conditions and low productivity. The developed convective drying unit allows solving these problems. It ensures uniform and rapid drying of kurt in controlled conditions, which improves quality and productivity. The unit is designed taking into account the principles of ease of maintenance, ease of operation and cost-effectiveness. It is affordable and cost-effective for individual entrepreneurs and small businesses. Availability, price, quality, productivity, maintainability, reliability, light weight and mobility of the equipment make it relevant for the development of small businesses in Kazakhstan. During the work, a number of tests were conducted on the performance of the drying unit. A sketch drawing was also developed, a drying unit was developed and the optimal operating parameters of the design were selected. The resulting drying unit is promising for implementation in the production of kurt, in the conditions of individual and farm enterprises. It will improve the quality and productivity of the product, as well as create new opportunities for small and medium businesses in Kazakhstan. Also, such equipment can give impetus to local gastronomic tourism, which is becoming an increasingly popular type of tourism, as tourists are looking for unique and authentic experiences. Offering tourists the opportunity to get acquainted with the local culture through its cuisine.

THE QUALITY AND SAFETY OF GOAT MILK SOUR-MILK PRODUCT

To improve the quality of life of the population, currently a promising direction is the use of functional foods. The article presents the results of the conducted analysis of the quality and safety of symbiotic yogurt from goat milk enriched with a mixture of vegetable raw materials.Purpose of the study: to study the effect of quince syrup on the quality and safety of fermented milk products.This paper presents the results of the study of the developed fermented milk product (yogurt) for functional purposes. The composition of the added ready-made starter includes the cultures Str.thermophiIlus, Lb.bulgaricus, Lb. acidophilus. Quince fruit syrup was used as a natural ingredient of plant origin.Addition of quince syrup in the production of yogurt from goat's milk contributes to obtaining a product enriched with dietary fiber, vitamins, macro-microelements, as well as increasing the range and improving the organoleptic properties of dairy products, including pectin-containing.The presented article provides comprehensive microbiological indicators of the studied yogurt samples and the dynamics of changes in lactic acid microflora during storage.The results showed that according to microbiological indicators, the yoghurts met the requirements of TR CU 033/2013, QMAFAnM did not exceed the specified standards, and coliform bacteria were absent. The growth of lactic acid bacteria in the studied samples was intense on the fifth day – 6.4×109 CFU, then the number of microorganisms decreased. On the seventh day, the number of lactic acid bacteria in the studied sample was – 4.5×108 CFU, the indicator of the control sample for this period was – 2.4×107 CFU.

Protein-added kefir: biochemical changes in in vitro digestion stages.

While yogurt is the leading fermented milk product, kefir is at the top of the beverage scale. Milk proteins, on the other hand, show specific functions that positively affect healthy nutrition due to the bioactive components, that they provide the necessary amino acids for growth and development. In our study, kefir, a functional product enriched with whey proteins, casein and skimmed milk powder, which are the natural components of milk, was produced. Added-protein kefir samples were applied the in vitro digestion protocol, static method. In order to observe different protein behaviors, samples were taken pre-digestion, at 120th minute and at 240th minute of digestion protocol. ACE and Antioxidant capacity determination analyzes were carried out. While ACE inhibition values were in the range of 78.63-90.30% pre-digestion, they changed in the range of 86.97-96.38% after gastrointestinal digestion. It was determined that the ACE inhibition values of the control sample remained at the lowest level at all stages of digestion and that the difference between all of samples was significant (P < 0.05). Antioxidant activity value ranging from 0.3615-0.5512 meq Ascorbic acid/μg before digestion was determined as 1.3796-1.9313 meq Ascorbic acid/μg after gastrointestinal digestion (P < 0.05). Kefir samples containing whey protein stand out with their high potential in terms of both antioxidant activity capacity and ACE inhibition activity at all stages of digestion. Considering their therapeutic effects in fermented products, it is thought that whey proteins among milk proteins will be important alternative sources to enrich the protein content in kefir production. © 2024 Society of Chemical Industry.

Chitosan and its derivatives regulate lactic acid synthesis during milk fermentation.

The influence of chitosan's physicochemical characteristics on the functionality of lactic acid bacteria and the production of lactic acid remains very obscure and contradictory to date. While some studies have shown a stimulatory effect of oligochitosans on the growth of Lactobacillus spp, other studies declare a bactericidal effect of chitosan. The lack and contradiction of knowledge prompted us to study the effect of chitosan on the growth and productivity of L. bulgaricus in the presence of chitosan and its derivatives. We used high molecular weight chitosan (350 kDa) and oligochitosans (25.4 and 45.3 kDa). The experiment was carried out with commercial strain of L. bulgaricus and the low fat skim cow milk powder reconstituted with sterile distilled water. After fermentation, dynamic viscosity, titratable acidity, pH, content of lactic acid, colony forming units, chitosan and oligochitosans radii were measured in the samples. Fermented dairy products were also examined using sodium dodecyl sulfate electrophoretic analysis, gas chromatography-mass spectrometry and light microscopy. The results of the study showed that when L. bulgaricus was cultured in the presence of 25.4 kDa oligochitosans at concentrations of 0.0025%, 0.005%, 0.0075% and 0.01%, the average rate of LA synthesis over 24 hours was 11.0 × 10-3 mol/L/h, 8.7 × 10-3 mol/L/h, 6.8 × 10-3 mol/L/h, 5.8 × 10-3 mol/L/h, respectively. The 45.3 kDa oligochitosans had a similar effect, while the average rate of lactic acid synthesis in the control sample was only 3.5 × 10-3 mol/L/h. Notably, 350 kDa chitosan did not affect the rate of lactic acid synthesis compared with the control sample. Interestingly, interaction of chitosan with L. bulgaricus led to a slowdown in the synthesis of propanol, an increase in the content of unsaturated and saturated fatty acids, and a change in the composition and content of other secondary metabolites. The quantity of L. bulgaricus in a sample with 0.01% chitosan exceeded their content in the control sample by more than 1,700 times. At the same chitosan concentration, the fermentation process was slowed down, increasing the shelf life of the fermented milk product from 5 to 17 days while maintaining a high content of L. bulgaricus (6.34 × 106 CFU/g).

STUDY OF STEVIA ECAPSULATION FOR USING IN PROBIOTIC DELIVERY SYSTEMS

At the moment, incoming products, beverages, raw materials on the market must comply with the requirements of State standards and safety requirements. The question of nutritional value is growing every day, based on the fact that the constant use of healthy foods develops the body's resistance to various diseases. Such products are called useful or functional products. An equally urgent task for today's specialists is the development of a functional fermented milk product that contains a pleasant sweet taste from natural Stevia plant extract. Stevia rebaudiana Bertoni is a natural sweetener, which has many useful properties. For example, one of the first benefits in low-calorie content does not include fast carbohydrates. So, Stevia has less effect on blood sugar levels and does not increase insulin and is suitable for diabetics. In addition, Stevia extract can be used as prebiotic for co-encapsulation with probiotic microorganisms to enrich functional beverages. Purpose of this study is investigation of formulation parameters for reсeiving саpsules whiсh сreаte а strong bаrrier to penetrаtion of the encapsulated substаnсe to the externаl environment; the саpsules providing more effiсient mаnifestаtion of а сomplex of biologiсаl, phаrmасologiсаl, preventive or mediсinаl properties of bаgged substаnсe. Development of cаpsules of the long term of storаge in whiсh the асtive loaded mаteriаl is proteсted by аn envelope аnd саn preserve activity in vаrious pH environments became the most perspective. Ionic gelation method through extrusion represents a simple encapsulation technique that does not require organic solvents, making it suitable for both hydrophobic or hydrophilic compounds. Stevia extract -loaded Alginate-Chitosan particles with improved physicochemical properties with a process yield of 88-89% were obtained. The release kinetics of active agent was monitored using UV-vis spectroscopy and showed a slow release within 24 hours. Thus, the slow kinetics of the release of the agent demonstrates the effectiveness of the methodology of encapsulation based on the ionic gelation and hardening of shell. Сreаtion of саpsules with the ingredients enсаpsulаted inside, hаving thermostаble properties, resistаnсe to influenсe of асidiс environments аnd enzymes, meсhаniсаl аnd osmotiс resistаnсe to influenсe of externаl physiсаl аnd сhemiсаl fасtors, suсh аs meсhаniсаl effeсt, temperаture inсreаse, сhаnge of pressure, аnd аlso inсreаse in proteсtion of bаgged substаnсes remains as an actual problem at present time. The morphology, average diameters of wet and dry microcapsule were determined by optical microscopy using Olympus Soft Imaging Solutions GmbH, version E_LCmicro_09Okt2009. Twenty microparticles were randomly selected from triplicate batches to determine size distribution. The compositions of microcapsules for analysis on a scanning electron microscope were applied to a highly conductive graphite tape. SEM equipment was used to determine the pore size on the surface of the microparticles. Studies results showed that sizes of microcapsules were 720-830 µm, and color was determined by color of loaded agent. Microencapsulation allows not only protect active agent from aggressive environment, prolong activity, but also can be used for development product with useful properties for human health. Funding: This research is funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP19679879).