Yogurt Samples Research Articles

WITHDRAWN: Set-type yogurt with Cucumis melo L. (Kultik) seeds

In this study, possible use of Kultik seed as an alternative food ingredient in production of set yogurt was evaluated. Set-type yogurts were produced from different mixture ratios of cow's milk and kultik seed water extract, and only from kultik seed water extract using transglutaminase. In addition, effect of storage time on yogurt properties were investigated. The properties were total solids, ash and fat content, acidity as pH, titratable acidity as % of lactic acid, syneresis, viscosity features, total phenolic content, antioxidant activity and sensory evaluation.Overall, it was not possible to produce a set-type yogurt only using the seed water extract, however, a vegetarian yogurt was possible to be produced from mixture of the seed water extract and cow's milk. The evaluated properties changed in a ratio-dependent manner. Storage time led syneresis and titratable acidity to increase, and total solid content to decrease due to ongoing fermentation throughout storage period in yogurt samples, p<0.05. Even though the seed water extract addition in yogurt production not only resulted to the decrease in some properties, but also the increase in total solids, fat content and syneresis. Sensory evaluation of costumers in acceptance proved that there is a huge potential to produce a functional food like a set-type yogurt using the seed water extract due to better taste quality and overall acceptance scores of the yogurt produced from 20% the seed water extract+ 80% cow's milk rather than any of other samples including the control at the storage time of 1 day and 15 days. Therefore, the seed water extract has an enormous potential as an alternative vegetarian source for production of fermented dairy products for who have disability of lactose tolerance.

Biotechnology for the development of a functional fermented milk product using vegetable raw materials

This article discusses the possibility of using flour from pomegranate waste and persimmon waste as a biologically active additive in yogurt formulations. To assess the effect of the additive used, the dynamics of titrated acidity during sample storage was studied, and dynamic viscosity was considered. Since the main indicators of product quality for the consumer are its organoleptic properties, the taste, smell, color and consistency of the developed samples of low-fat yogurt were evaluated. It was determined that in the formulation of low-fat yogurt, the optimal use of flour from pomegranate waste in an amount of 2.0%. The introduction of a fruit additive from persimmon flour into the prototypes was 1, 3, 6, 9% by weight. The results of the degree of syneresis and viscosity indicate a positive effect of the additive on the formation of a milk clot. In low-fat yogurt without the addition of flour from pomegranate waste, the texture of the milk clot was not oily, loose and less viscous, and with an increase in the mass of the added additive, the smell and taste became more pronounced, the color of the yogurt turned pink. Studies show that adding persimmons to yogurt can increase the content of antioxidants, in particular lycopene, which exhibits the strongest antioxidant properties among carotenoids, vitamins and minerals. The nutrients contained in persimmons, combined with probiotics from yogurt, can have beneficial effects on digestion, strengthen the immune system and promote overall health.

Characterization of Lactic Acid Bacterium Exopolysaccharide, Biological, and Nutritional Evaluation of Probiotic Formulated Fermented Coconut Beverage.

Exopolysaccharides (EPSs), produced by lactic acid bacteria (LAB), play a crucial role in enhancing the texture and stability of yoghurt by forming a protective matrix that helps to maintain its rheological and sensory characteristics. The search for a dairy alternative for the lactose-intolerant populace is a necessity, and the use of probiotic LAB and their EPS to formulate fermented coconut beverage (FFCB) will be of added advantage. The production and characterization of EPS from a LAB strain isolated from yoghurt, its probiotic and antioxidant potential, and its application in the production of probiotic FFCB were investigated. The EPS produced by the isolate was characterized using a scanning electron microscope (SEM), high-performance liquid chromatography, Fourier transform infrared (FT-IR) spectroscopy, and energy-dispersive X-ray. The antioxidant potential of the EPS was determined. The isolate probiotic potential, such as tolerance to low pH, bile salts, gastric pH, autoaggregation, coaggregation, antimicrobial potential, and antibacterial activity, was evaluated, and the isolate was identified using 16S rRNA. The LAB strain and the EPS were used for the formulation of probiotic FFCB, and the proximate mineral composition of the enriched yoghurt was determined. Isolate W3 produced 6204.50 mg/L EPS. The EPS produced by the LAB was spherical with a coarse surface. Hydroxyl, carboxyl, and α-pyranose were the major functional groups present in the EPS. Eight monosaccharides were present in glucose, which has the highest molar ratio. The EDX spectra ascertain the presence of carbon, oxygen (carbohydrate), and other elements. The purified EPS exhibited antioxidant activity in a dose-dependent manner. DPPH, FRAP, TAC, and TPC of the EPS ranged from 42.36% to 75.88%, 2.48 to 5.31 μg/mL, 1.66 to 3.57 μg/mL, and 1.42 to 2.03 μg/mL, respectively. The LAB strain exhibited moderate tolerance to low pH, bile salts, gastric juice, good autoaggregation (13.33%), coaggregation (0%-59.09%) with E. coli, and varied sensitivity to different antibiotics used. The isolate is hemolysis, deoxyribonuclease (DNase), and lecithinase negative, possesses characteristics of probiotics, and could have the ability to confer health benefits. The LAB strain has a 100.0% pairwise identity to Pediococcus acidilactici. The FFCB has pH, lactic acid, specific gravity, total soluble solids (TSSs), and vitamin C content ranging from 5.81 to 6.8, 10.8 to 55.8 mg/L, 0.910 to 1.394 kg/m3, 0.136 to 0.196 °Bx, and 0.26% to 0.66%. The formulated beverage fermented with a commercial starter had the highest lactic acid at Day 7 of storage. The FFCB sample with the commercial starter and the probiotic strain had the highest ash and crude fiber content (1.3%, 0.68%). The FFCB fortified with EPS showed the highest protein content (4.6%). The formulated yogurt samples fortified with the highest concentration of EPS had the highest calcium content after 7 days of storage (162.31 ± 0.01a). In conclusion, EPS produced by Pediococcus acidilactici was a heteropolymeric EPS with good antioxidant activity, and the LAB strain exhibited a good starter for producing FFCB enriched with EPS. The FFCB has good nutritional characteristics and could serve as a functional and natural nutraceutical food for the lactose intolerance population.

Quality Evaluation of Herbal Yoghurt Produced Using Cinnamon (Cinnamon cassia), Garlic (Allium sativum) and Ginger (Zingiber officinale)

Yoghurt is a widely consumed fermented dairy product, known for its flavour and perceived health benefits. To create herbal yoghurt with unique attributes, different amounts (0, 4, 6 and 8 g) of cinnamon, garlic and ginger were incorporated into the yoghurt postfermentation, resulting in multiple samples. The research assessed various aspects of the herbal yoghurt, including proximate composition, micronutrients, physicochemical properties, antioxidant content, sensory attributes and microbiological characteristics. The proximate analysis revealed variations in moisture (86.67% to 87.79%), protein (4.26% to 4.28%), fat (3.82% to 3.91%), ash (0.88% to 0.95%) and carbohydrates (0.12% to 1.73%). The vitamin C content ranged from 0.21 mg/100 mg to 0.21 mg/100 mg, and vitamin A content from 2.79 IU to 2.86 IU. Phosphorus and calcium content varied from 90.43 mg/100 mg to 91.87 mg/100 mg and 53.72 mg/100 mg to 53.83 mg/100 mg, respectively. The herbal yoghurt exhibited a pH range of 4.57 to 4.67, total titratable acidity from 0.43 to 0.51 and IC50 for DPPH values from 20.83 to 21.78. In terms of sensory evaluation, the control sample (YCTRL) garnered the highest mean scores for all attributes, including appearance, aroma, taste, aftertaste, mouthfeel, consistency and overall acceptability. Panellists rated YGP1, which contained 4 g of ginger powder, as the herbal yoghurt with the most acceptability. Microbiological analysis indicated that the total viable count ranged from 7.9 × 102 (cfu/ml) to 1.1 × 103 (cfu/mL), with lactic acid bacteria counts varying from 1.4 × 103 (cfu/mL) to 2.3 × 103 (cfu/mL). Notably, no mould was detected in any of the yoghurt samples or the control, possibly due to the stringent aseptic conditions and hygienic measures maintained during production. From the results obtained, herbal yoghurt can serve as a highly nutritional functional food enriched with a variety of health benefits.

Physico-chemical and Microbiological Study of Curd(yoghurt) Fortified With Spices

Dairy products such as yogurt are widely used, so fortifying this food with spices is helpful to increase its nutritional value of it. Spices contain antioxidant activity, proteolytic activity, and bioactive compounds which are very helpful for human health. The main focus is to examine the technical element and microbiology involved in the manufacturing of various varieties of yogurt. Various types of yogurt were prepared by adding Black pepper, Cinnamon, Clove, and dry ginger. The yogurt formed was subjected to physicochemical and microbiological analysis. The time required for yogurt formation was found to be 10 h. The yogurt samples fortified with spices were found to be of smooth texture, white color having a pleasant smell and sour taste.

Bio-hydrolysis Study of Lactose in Produced Yoghurt by β-Galactosidase from Lactobacillus fermentum

The present study investigated the physicochemical and biohydrolysis of lactose in conventional and locally produced yoghurt drinks, respectively. Physicochemical properties of the conventional yoghurt in the presence of the locally produced one were: pH 3.0; 4.0, titratable acid 1.14; 1.04, conductivity 2751.54, 2204, viscosity 71.11; 112.14, TDS 1788.5; 1433, TSS 781; 654, TS 3532.54; 2087, Mg 11.06; 34.19, Ca 28.76; 45.21, TOC 155.23; 145.23 and TOM 190.93, 178.63 for yoghurt sample I and II respectively. Lactose concentrations of the respective yoghurts were: 2.12 and 1.79 Mg/ml. β-galactosidase was produced from isolated Lactobacillus sp under submerged fermentation system after 12 days of incubation. 60% ammonium sulphate was found suitable for precipitation of proteins with highest enzyme activity, the precipitate was desalted through reverse osmosis using dialysis bag. Optimum biohydrolysis was achieved after 20 hours of incubation with residual sugar concentration of 0.51 mg/ml while the control experiment had 0.93 mg/ml of the residual sugar. Optimum pH and temperature of hydrolysis were: 5.0 and 70°C respectively. Rate of hydrolysis proceed linearly as the enzyme concentration increases from 0-20% v/v. the present study has shown exclusively the nutritional components of yoghurts drinks commercially sold in the market, it went further to show hope for the metabolic compromised individuals with intolerance to lactose as the enzyme lactase produced from non noscomial organism showed great potentials of hydrolysis.

Pengaruh Pemberian Beberapa Jenis Yogurt Komersial terhadap Jumlah Profil Darah Tikus (Rattus norvegicus) yang Diinduksi Diabetes Melitus

Diabetes mellitus is a metabolic disorder that occurs due to inadequate insulin levels or insulin resistance which leads to hyperglycemia. Handling hyperglycemia conditions in diabetes mellitus is very necessary, one of which is by consuming healthy and nutritious food. The aim of this research is to determine the results of total antioxidant levels in types of yogurt which can have an influence on the blood profile of white rats (Rattus norvegicus) with diabetes mellitus. This research used white rats (Rattus norvegicus) as experimental animals which were divided into 5 groups (K+: normal type, K-: negative type (alloxan), P1: type I yogurt brand (drinking yogurt), P2: type. yogurt brand II (yogurt set), P3: kel. yogurt brand III (stirred yogurt) with 5 treatment repetitions each. Yoghurt was given using the oral sonde technique to the experimental animals. Blood samples from the experimental animals were taken through the orbital sinus using hematocrit. Profile Rat blood was tested using a hematology analyzer. The data obtained were analyzed using one-way ANOVA and Duncan's test with a significance level of 0.05. Statistical results showed that there were significant differences (p &lt; 0.05) in each treatment group. Based on the average results erythrocytes, hemoglobin, leukocytes and platelets that brand III yogurt samples had a better level of improvement than the others. This is also in line with the results of testing antioxidant levels in brand III yogurt, namely 51.38 ppm, which means the antioxidant levels are strong.

Determination of Chemical and Microbiological Quality of Strained Yoghurt Samples Marketed in Aydın Province

In this study, 60 strained yoghurt samples, including 30 public bazaar and 30 dairy-markets were examined in terms of chemical and microbiological properties. According to chemical analysis of bazaar samples, average levels of pH, acidity, fat, protein, salt, total solid and ash are determined; 3.94, 2.19% (LA), 8.09%, 11.21%, 1.83%, 21.74%, 0.71%, respectively. The average levels of given elements above in samples gathered from dairy stores are determined; 3.94, 1.86% (LA), 9.47%, 11.95%, 1.81%, 23.26%, 0.71%, respectively. No presence of starch was found in any of the samples. The chemical analysis results of the strained yoghurt samples were determined in accordance with the values specified in Turkish Food Codex except for the amount of fat analysis gave a result over the specified value. Coliform bacteria level was determined

Investigation of aroma profiles, textural, rheological, and sensorial qualities of yogurts with various starter cultures and goat–cow milk combinations

Abstract In the present study, aroma components, textural, rheological and sensory qualities of yogurts produced using YC-350 and ABT-2 starter cultures and combinations of goat/cow milk were investigated during the storage period. For this purpose, aroma components were analyzed by GC-MS, textural analyses by TA.XTplus Texture Analyzer and rheological analyses by Anton Paar MCR 102 rheometer. The effects of goat/cow milk combinations and variety of starter culture on aroma components, textural, rheological and sensory properties of yogurt samples were found significant (p &lt; 0.01). Also, the storage period significantly (p &lt; 0.01) affected all parameters tested except cohesiveness, resilience, and appearance. While it was found that the use of cow milk in the experimental yogurt samples increased the acetaldehyde content, it was found that it had varying effects on the diacetyl content, acetoin content, and textural and rheological analysis parameters. It was determined that the content of diacetyl and acetoin reduced with the progression of the storage times. In the sensory evaluations, the use of goat milk had positive effects on the parameters of appearance and consistency by spoon, and the use of probiotic culture (ABT-2) had positive effects on the parameters of consistency by mouth and overall acceptability.

Influence of green pepper extract on the physicochemical, antioxidant, and sensory properties of stirred yogurt

The green pepper has garnered interest in different societies as a functional food and food additive. Numerous studies have indicated that the phytochemicals found in pepper possess antioxidant, anti-cancer, anti-inflammatory, anti-obesity, and anti-arteriosclerotic properties. In this study, green pepper extract was used in yogurt to increase the acceptability of consumption and improve its health properties. For this purpose, green pepper extract was added in concentrations 100, 200, and 300 ppm in the preparation of yogurt. And pH, acidity, total content of phenolic compounds, DPPH inhibition percentage, viscosity, syneresis, and sensory properties were evaluated in 1, 7, 14, and 21 days after production. The results showed that by increasing the amount of extract, the percentage of antioxidant activity and phenolic compounds increased significantly. The effect of storage time on these indicators was also significant (p < 0.05). in such a way that over time, there was a decrease in antioxidant activity. But, there was a slight increase in antioxidant activity on the 14th day of storage. Also, the effect of treatment type on some physicochemical characteristics of yogurt containing green pepper extract including pH, acidity, viscosity, and syneresis was significant (p < 0.05). During storage, acidity, syneresis, and viscosity increased and pH decreased significantly in all yogurt samples. Regarding the tested sensory attributes, the 200 ppm sample received the highest score among the evaluators, and in terms of overall acceptance, the samples containing the extract were more favorable than the control sample.

Investigating the impact of exopolysaccharides on yogurt network mechanics and syneresis through quantitative microstructural analysis

Exopolysaccharides produced by lactic acid bacteria are widely used to improve the sensory properties of yogurt. The relation between the physical properties of the microbial exopolysaccharides and the structural and rheological properties of the yogurt are incompletely understood to date. To address this knowledge gap, we studied how two distinct exopolysaccharides influence the microstructure, rheological properties, and syneresis of yogurt. The effect of a negatively charged, capsular exopolysaccharide produced by Streptococcus thermophilus and a neutral, non-capsular exopolysaccharide produced by Lactococcus lactis were investigated. Using quantitative microstructural analysis, we examined yogurt samples prepared with either the capsular or the non-capsular exopolysaccharide, and with mixtures of the two. Confocal laser scanning microscopy and stimulated emission depletion microscopy were employed to visualize the microstructures, revealing differences in pore size distribution, protein domain size, and casein interconnectivity that were not apparent through visual inspection alone. Additionally, variations in rheological properties were observed among the different yogurt types. In the yogurt fermented with both bacterial strains, we observed a combined impact of the two exopolysaccharide types on relevant microstructural and rheological properties. The negatively charged capsular exopolysaccharide enhanced casein interconnectivity and gel stiffness, while the neutral non-capsular exopolysaccharide led to thicker protein domains, an abundance of small pores, and a lower loss tangent. These factors collectively hindered syneresis, resulting in improved structural integrity. Our study not only provides valuable insights into the influence of different exopolysaccharides on yogurt properties, but also presents the first demonstration and quantification of the effect of multiple types of exopolysaccharides on casein interconnectivity. These findings offer guidance for the production of yogurts with customized microstructure, rheological properties, and resistance to syneresis.

Isolation of Lactic Acid Bacteria from Local Yogurt Samples in Chaharmahal and Bakhtiari Province: The Assessment of Probiotic Characteristics

Isolation of Lactic Acid Bacteria from Local Yogurt Samples in Chaharmahal and Bakhtiari Province: The Assessment of Probiotic Characteristics

Identification of Previously Unrecorded Bacills, Serratia, and Mucor Strains Isolated from Yogurt

(1) Background: Foodborne illnesses are recognized as a significant threat to public health and the economy in both developed and developing nations. The safety of foods containing microorganisms has consequently become a major worldwide concern. One of the most frequent causes of food deterioration in the world is microbial contamination. (2) Methods: Yogurt containers that were bought commercially in Riyadh, Saudi Arabia during their validity period contained four different species of bacteria and one type of fungus. Using nutritional agar and Czapek-Dox agar medium, the bacteria and fungi were isolated. The isolates of the fungi and bacteria were identified using a scanning microscope. The isolates were further identified and classified for molecular evolutionary analyses using the 16S rRNA and ITS sequences from the bacteria and fungi, respectively, in conjunction with the universal primers 27F, 1492R, ITS1F, and ITS4R. (3) Results: A total of 131 separate strains were identified from 12 yogurt samples based on their phenotypic characteristics. In total, 79 isolates (60.3%) consisted of Serratia marcescens, Bacillus subtilis, and Mucor circinelloides, with 52 isolates (39.7%) being Bacillus cereus. While the cells of Bacillus and Serratia are shaped like rods, the sporangia of Mucor are large, round, and black. Each strain was identified by its accession number, which were as follows: MK590996.1: B. cereus; MK591144.1: B. subtilis; MK591002.1 and MK591014.1: S. marcescens; and MK559692.1: M. circinelloides. The maximum identification was found to be between 98.64 and 100% when BLAST was used to compare the sequences to the NCBI GeneBank database. (4) Conclusions: Genus and species identification was performed using the similarity score values. Yogurt products containing high concentrations (39.7%) of Bacillus cereus isolates carry a significant risk of health hazards due to the potential for spreading pathogenic bacteria to humans.

Effect of roasting and high-pressure homogenization on texture, rheology, and microstructure of walnut yogurt

The effect of roasting and high-pressure homogenization on the quality of yogurt made from peeled walnut kernels was explored in this study. The G' and G'' values of yogurt made from walnuts roasted at high temperatures were reduced. The water-holding capacity and hardness of walnut yogurt were reduced to 47.73% and 24.22 g, respectively. Increasing the homogenization pressure reduced the particle size of the walnut yogurt to 20.50 μm. Homogenized walnut milk at 150 MPa increased the viscosity, hardness, and consistency of yogurt product from 11.71 to 16.74 Pa.s, from 30.01 to 71.63 g and from 283.17 to 455.24 g·s, respectively. The confocal laser scanning microscope observation demonstrated a reduction in the size of fat and protein micelles in the homogenized yogurt samples, resulting in a compact structure. This study will contribute valuable scientific insights to the advancement of plant-based yogurt quality.

Yoghurt quality when using probiotic starter cultures and vegetable filler

In order to increase the biological value of yogurt, increase and improve its assortment, it is necessary to continue the search and use of new additives and fillers of natural origin. Such fillers should be well combined with the milk base, contain mineral elements, vitamins and other biologically active substances. The article substantiates the use of bacterial starters and vegetable filler in yogurt technology. The results of studies on the use of dry bacterial starter cultures of direct application of the Ukrainian manufacturer of the “YOGURTON” trademark and the vegetable filler “Black currants dry extract of 30 % anthocyanins” in the production of yoghurt are presented. An evaluation of the prototypes showed that when using the Yoghurt Probio TM «YOGURTON» starter, the product had a more pronounced taste and smell. The time of clot formation, changes in titrated acidity, and organoleptic characteristics of yogurt with filler were studied. It was found that all samples of yogurt on organoleptic parameters meet the requirements of DSTU and high scores on the scoring system of fermented milk products. The tested starter cultures at a fermentation temperature range of 40 ± 2 °C form a clot for 6–8 hours with a titratable acidity of 75 °T. Yogurt with a content of dry currant powder in an amount of 1 % in terms of organoleptic characteristics turned out to be the best; with an increase in the content of currant powder in yogurt up to 1.5 %, an increase in the taste of currants and a decrease in the characteristic sour milk taste of the product were noted. High acidity gives the product a sour taste and smell, which reduces its organoleptic characteristics. The acidity of yogurt with a filler content of 1 % was 116 °T on the first day of storage and increased to 140 °T for ten days. During storage of yogurt at the temperature of +6 ± 2 °C there is a gradual increase in lactic acid microorganisms, which affects the organoleptic characteristics of yogurt. “Black currant extract dry 30 % anthocyanins” enriches yogurt with anthocyanins, flavonoids, organic acids, pectin, which improve the taste and quality of the product.

Technology of fermented milk product with increased protein content

The article contains the results of research into the development of yogurt technology with a high protein content and added Jerusalem artichoke syrup. Milk protein contains casein and whey protein, so it is a valuable source of protein. Modern technologies make it possible to separate and purify a specific type of milk proteins to a concentration that meets the technological requirements that are necessary in food systems. The low glycemic index and probiotic properties has a Jerusalem artichoke syrup, it has a positive effect on the development and stability of lactic acid bacteria and is recommended for consumption by people with diabetes. The biological value of the whey isolate was studied and it was established that the content of essential amino acids is 47.7 g per 100 g of the product, or 48.4 % of the total amount of amino acids. The content of BCAA (leucine, isoleucine and valine) is 23 g, which is 23.3 % of the total amount of amino acids. It was found that lysine has the highest score (176.3 %), and the limiting amino acids are phenylalanine (50 %) and methionine (62.8 %). The sum of amino acids of the “ideal” protein according to the recommendations of FAO/WHO and whey protein isolate was compared, and it was determined that the protein content in the studied raw material is 460 mg, which exceeds the values of the “ideal” protein (360 mg) by 27.7 %. It has been experimentally established that the optimum from the point of view of the complex of organoleptic properties and cost of the product is the sample where the content of whey isolate is 7.2 g per 100 g of the product. The protein content per 100 g of finished yogurt is 10 g. During fermentation, a slight difference in the rate of change of acidity in yogurt samples was noted, which was 4.5 h (75 °T) in the experimental sample and 5 h in the control sample. The shelf life of the product is set for 12 days according to titrated acidity levels for 21 days. According to the organoleptic indicators of yogurt, the difference between the tested and the control sample was noted. Yogurt, with added protein and Jerusalem artichoke syrup, was rated highest for taste, smell, and consistency, but not rated high enough for appearance and color. Regarding the biological value of the product, the protein content is 10 %, the fat content is 2.5 %, and the carbohydrate content is 8.3 %. The energy value of yogurt with additional ingredients is 84.4 kcal per 100 g of product.

Effects of mulberry pomace polysaccharide addition before fermentation on quality characteristics of yogurt

Mulberry pomace, a by-product of mulberry juice processing, is rich in natural bioactive substances including polysaccharides and polyphenols and is useful for the production of functional foods. As such the effects of mulberry pomace polysaccharide (MPP) on physicochemical, textural and microstructural features of yogurt during cold storage were investigated. MPP was incorporated into reconstituted skim milk at 0% (control), 0.5%, 1.0% and 1.5%, respectively and then fermented to yogurt and stored at 4 °C for 28 days. The color, pH, titratable acidity, syneresis, rheology, texture and microstructure of yogurt samples were analyzed. The addition of MPP before fermentation dose-dependently affected the pH value and titratable acidity of yogurt samples such that the addition of 0.5% MPP showed the most significant effect in reducing syneresis, increasing gel strength and viscosity, and improving texture and microstructure of yogurt. The results indicate that the appropriate amount of MPP can effectively improve the gel properties and physicochemical parameters of yogurt, and MPP played an important role in the yogurt quality improvement by mulberry pomace.

An oxygen-insensitive amperometric galactose biosensor based on galactose oxidase co-immobilized with an Os-complex modified redox polymer

Monitoring galactose levels in dairy products can help to prevent severe complications with a hereditary metabolic disease such as galactosemia, a life-threatening disease. The current state of the art requires the development of less expensive, more reliable and specific methods to determine galactose levels in food in a practical way. We report the development and optimization of an amperometric biosensor for determination of galactose in dairy products based on galactose oxidase (GaOx) co-immobilized with an osmium-complex modified redox polymer on glassy carbon electrodes. To attain the maximum catalytic currents based on mediated electron transfer, two Os-complex based polymers with different redox potentials and different enzyme:redox polymer ratios were studied. The optimized GaOx-modified electrode gave a maximum electrocatalytic response of galactose oxidation that was not affected by the presence of O2, indicating fast wiring of the enzyme by the Os-complex modified redox polymer. The biosensor that gave the best analytical parameters for galactose detection was further tested for measuring galactose concentration in lactose-containing and lactose-free milk and yogurt samples under aerobic conditions. The results obtained with the amperometric biosensor were validated by high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD).

Physicochemical properties and survival assessment of potential probiotics in a novel dairy drink during storage.

A novel fermented dairy drink utilizing microbial strains displaying potential probiotic attributes was formulated. The study constituted several experimental cohorts, including Lactiplantibacillus plantarum AB6-25, isolated from a human stool sample; Lacticaseibacillus casei K2, sourced from a koumiss sample; Lacticaseibacillus rhamnosus 3B7, derived from a traditional yogurt sample; and identical lactic acid bacteria (LAB) in combination with yeast (Saccharomyces boulardii T8-3C from chicken feces) strains. Two distinct iterations of probiotic-fermented dairy drinks were generated by introducing subcultured microorganism cultures: LAB strains at a concentration of 1% each (designated as combination A) and a blend of LAB strains at 1% each along with T8-3C at 0.5% (designated as combination B) into both whole and semi-skimmed milk matrices. The fermentation process persisted until the pH reached 4.6 under constant conditions of 37 ± 1°C. Subsequently, the samples were held at 4 ± 1°C for 15 days. The groups' physicochemical, microbiological, and sensory characteristics were determined on days 1, 8, and 15 of storage, and the protein profile was determined. Standardized regression analysis and principal component analysis evaluated the results. Fat content affected the changes in dry matter. pH decreased in all samples during storage, particularly in the yeast group. The microorganism group positively affected syneresis, whereas fat content and the interaction of fat content and the microorganism group had a negative effect. The most critical factor in the decrease in syneresis was the increase in fat content. LAB and yeasts maintained their probiotic effects during storage, with a viability level of approximately 109 and 108 cfu/mL, respectively.

Influences of Yogurt with Functional Ingredients from Various Sources That Help Treat Leaky Gut on Intestinal Barrier Dysfunction in Caco-2 Cells.

The impact of yogurts made with starter culture bacteria (L. bulgaricus and S. thermophilus) and supplemented with ingredients (maitake mushrooms, quercetin, L-glutamine, slippery elm bark, licorice root, N-acetyl-D-glucosamine, zinc orotate, and marshmallow root) that can help treat leaky gut were investigated using the Caco-2 cell monolayer as a measure of intestinal barrier dysfunction. Milk from the same source was equally dispersed into nine pails, and the eight ingredients were randomly allocated to the eight pails. The control had no ingredients. The Caco-2 cells were treated with isoflavone genistein (negative control) and growth media (positive control). Inflammation was stimulated using an inflammatory cocktail of cytokines (interferon-γ, tumor necrosis factor-α, and interleukin-1β) and lipopolysaccharide. The yogurt without ingredients (control yogurt) was compared to the yogurt treatments (yogurts with ingredients) that help treat leaky gut. Transepithelial electrical resistance (TEER) and paracellular permeability were measured to evaluate the integrity of the Caco-2 monolayer. Transmission electron microscopy (TEM), immunofluorescence microscopy (IM), and real-time quantitative polymerase chain reaction (RTQPCR) were applied to measure the integrity of tight junction proteins. The yogurts were subjected to gastric and intestinal digestion, and TEER was recorded. Ferrous ion chelating activity, ferric reducing potential, and DPPH radical scavenging were also examined to determine the yogurts' antioxidant capacity. Yogurt with quercetin and marshmallow root improved the antioxidant activity and TEER and had the lowest permeability in fluorescein isothiocyanate (FITC)-dextran and Lucifer yellow flux among the yogurt samples. TEM, IM, and RTQPCR revealed that yogurt enhanced tight junction proteins' localization and gene expression. Intestinal digestion of the yogurt negatively impacted inflammation-induced Caco-2 barrier dysfunction, while yogurt with quercetin, marshmallow root, maitake mushroom, and licorice root had the highest TEER values compared to the control yogurt. Yogurt fortification with quercetin, marshmallow root, maitake mushroom, and licorice root may improve functionality when dealing with intestinal barrier dysfunction.