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INTRODUCTION There has been a rising demand for probiotic yoghurts over the last few years largely due to food consumers' awareness of the relationship between diet and the gastrointestinal tract [...], With the increasing demand of health promoting food products, formulations of yoghurts are changing more towards live probiotic starter culture milk fermentation and fortification with plant-based food ingredients to improve the flavour and nutrition composition. Synbiotic yoghurts fermented with probiotic microbes and fortified with prebiotic food ingredients have become very popular as functional foods due to their scientifically proven bioactive compounds that promote human gut health and alleviate dysbiosis. The aim of the current study therefore, was to assess the physiochemical, nutritional proximate composition and viability of probiotics in formulated yoghurt fortified with a novel purple-leaf tea (Camelias sinensis) puree that is rich in anthocyanins, bioactive polyphenols. Whole milk was fermented with probiotic starter culture (Lactobacillus acidophilus (LA-5), Bifidobacterium animalis subsp. lactis -ABT 5) from CH Hansens Limited. Subsequently, the yoghurt was fortified with a novel purple tea puree at the Food and Tea Science Workshop of Karatina University, Kenya. Proximate composition and physiochemical properties (pH and mineral salts profile) were analyzed both in the formulated probiotic yoghurt (PYFPT) and control yoghurt without the tea puree. The viability of the probiotic colony forming microbes was determined using the De Man, Rogosa and Sharpe (MRS) anaerobic bacteria selective culturing agar media. The pH results of PYFPT (4.24 [+ or -] 0.04) was not significantly different (p< 0.05) to that of the control yoghurt even after 28 days of refrigerated storage. However, proximate composition recorded significant differences except for the crude fiber content (0.01 [+ or -] 0.01%). A higher percent moisture content and crude lipid was recorded in the control yoghurt (88.18[+ or -]0.01 and (2.11 [+ or -] 0.02) than the PYFPT (78.14[+ or -]0.04 and 1.33 [+ or -] 0.09). Inversely, higher percentage of crude protein, carbohydrates and crude mineral salts were recorded in the formulated PYFPT (7.96[+ or -]0.27, 11.17[+ or -]0.25; 0.81[+ or -]) than control yoghurt (4.23[+ or -]0.01, 5.44[+ or -]0.04, 0.59[+ or -]0.01). A profile of ash content of the added purple tea puree recorded 16 different mineral salts. The macro minerals were the major, with potassium recording the highest content (282 ppm), followed by sodium (121 ppm), magnesium (97.2 ppm) and calcium (96.4 ppm). The microbial anaerobic probiotic count (6.14 - 6.80 log CFU/ml) was not statistically and significantly different between the PYFPT and the control yoghurt after 28 days of refrigerated storage. In conclusion, the study demonstrated that it is feasible to formulate nutritious probiotic yoghurt fortified using purple-leaf tea puree with potential for commercialization. Key words: Probiotic yoghurt, purple-leaf tea, physiochemical property, proximate composition, probiotics viability

Even though plant proteins are more plentiful and affordable than animal proteins in comparison, direct usage of plant-based proteins (PBPs) is still limited because PBPs are fed to animals as feed to produce animal-based proteins. Thus, this work has comprehensively reviewed the effects of various factors such as pH, temperature, pressure, and ionic strength on PBP properties, as well as describes the protein interactions, and extraction methods to know the optimal conditions for preparing PBP-based products with high functional properties and health benefits. According to the cited studies in the current work, the environmental factors, particularly pH and ionic strength significantly affected on physicochemical and functional properties of PBPs, especially solubility was 76.0% to 83.9% at pH = 2, while at pH = 5.0 reduced from 5.3% to 9.6%, emulsifying ability was the lowest at pH = 5.8 and the highest at pH 8.0, and foaming capacity was lowest at pH 5.0 and the highest at pH = 7.0. Electrostatic interactions are the main way for protein interactions, which can be used to create protein/polysaccharide complexes for food industrial purposes. The extraction yield of proteins can be reached up to 86–95% with high functional properties using sustainable and efficient routes, including enzymatic, ultrasound-, microwave-, pulsed electric field-, and high-pressure-assisted extraction. Nondairy alternative products, especially yogurt, 3D food printing and meat analogs, synthesis of nanoparticles, and bioplastics and packaging films are the best available PBPs-based products. Moreover, PBPs particularly those that contain pigments and their products showed good bioactivities, especially antioxidants, antidiabetic, and antimicrobial. [ABSTRACT FROM AUTHOR]

Backgrounds: Safe dental treatments that prevent nosocomial and cross-infections are essential for patients and dental workers. However, dental students sometimes pay inadequate attention to infection control, especially in preclinical practice, because of too much focus on technical training, such as the use of equipment, etc. The spread of infections such as SARS-CoV-2, antibiotic-resistant bacteria, and oral bacteria are sometimes lethal for medically compromised patients. Thus, the rapid and inexpensive detection system to detect and measure dental practice-related infection spread during preclinical treatment is highly desired for dental education. This study aimed to establish a method to quantify and visualize infected areas using dental phantoms for safe and effective preclinical dental practices. Methods: At first, we developed artificial saliva as an in vitro study, including food-derived bacteria and fluorescence dye, which is safe for application to preclinical practice education. In vitro study, the correlation between adenosine triphosphate (ATP) levels and Lactobacillus colony numbers in yogurt was examined using the ATP fluorescent method, with colony counting on yogurt only and a mixture of yogurt and ultraviolet (UV)-sensitive hand lotion. The mixed liquid of yogurt and hand lotion was used as artificial saliva. Second, we used this artificial saliva in preclinical education. The degree of contamination of personal protective equipment and dental chairs in preclinical practice using this artificial saliva was determined using the ATP fluorescent method and measuring the luminescence areas among 10 dentists, 10 dental residents, and 10 fifth-grade dental students. Results: ATP levels and Lactobacillus colony numbers in yogurt were positively correlated with yogurt alone and a mixture of yogurt and UV-sensitive hand lotions (correlation coefficient ≒ 1). Preclinical education using a mixture of artificial saliva successfully quantified and visualized infectious areas and droplets, which revealed significant differences in ATP amounts in personal protective equipment among groups according to years of experience as dental practitioners (p < 0.05). Conclusions: An education system for infection control constructed using artificial saliva containing Lactobacillus and a UV-sensitive fluorescent hand lotion quantified the infectious areas and degrees. Thus, this method is effective in preclinical practice using dental phantoms. [ABSTRACT FROM AUTHOR]

Yogurt is one of the most popular fermented milk products consumed worldwide. Fortification of yogurt with different food components, including fruit pulp, is a common practice to make it more palatable and healthier. In India, mango fruit is easily available. It is rich in nutrients and bioactive components. However, in-depth studies on mango fruit yogurt are scarce. Therefore, in this study, we prepared synbiotic mango fruit yogurt using response surface methodology (RSM) with three different independent factors (sugar 4%–6%; prebiotic inulin 1%–3%, and mango pulp 5%–15%) to determine the response antioxidant activity. The optimal conditions were as follows: sugar 6%, mango fruit pulp 6.562%, and prebiotic inulin 1%. There were no significant differences between the results of the experimental and predicted values of antioxidant activity by this model. The optimized product was analyzed for physicochemical, biofunctional, and technofunctional properties, including total polyphenol content, total flavonoid content, proteolytic activity, antioxidant activity, and ACE-inhibitory activity. The bioactive peptides derived from synbiotic mango fruit yogurt were also extracted (3 kDa, 5 kDa and 10 kDa) and determined for their biofunctional attributes. The antioxidant activity was recorded as 1,047.95 ± 2.20 mmol/L, 1,208.07 ± 2.92 mmol/L, and 1,293.09 ± 1.10 mmol/L Trolox equivalent antioxidant capacity, while ACE-inhibitory activity was 45.68% ± 1.23%, 64.20% ± 1.24% and 82.72% ± 1.24% inhibition in 3 kDa, 5 kDa, and 10 kDa, respectively. The 10 kDa bioactive peptide exhibited superior results than the 3 kDa and 5 kDa peptides. The synbiotic mango fruit yogurt and its bioactive peptides showed significant biofunctional activities. [ABSTRACT FROM AUTHOR]

Considering the great desire of consumers to consume traditional dairy products and their reluctance to use factory products, this study was conducted with the aim of investigating different chemical and microbial characteristics of traditional yogurt samples offered in Tuyserkan city and compare it with Pasteurized yogurt. The chemical characteristics including percentage of dry matter, moisture, acidity, pH and fat and microbial characteristics including total bacterial count, coliforms, mold and yeasts, and Staphylococcus aureus were investigated and compared with the pasteurized sample as a control sample. The moisture and dry matter content of the samples varied from 87.8-84.33% and from 12.62 to 15.25%, respectively. The fat content of the yogurts produced was between 2.5-2.9 and thus within the range of semi-fat yogurts according to the national standard. No significant difference was observed between different samples in terms of moisture, dry matter and fat (P>0.05). The acidity (percentage by weight in terms of lactic acid) and pH value of various samples ranged from 0.87-1.81 and 3.68-47.4, respectively and were therefore fully in line with the national standard (at least 0.7). Different samples showed a significant difference in terms of pH and acidity (P < 0.05). The results of microbial characteristics indicate the presence of mold and yeast in all samples (100%), coliform in 83.33% and Staphylococcus aureus in 50% of the samples. Regarding microbial characteristics, a significant difference was observed between traditional and industrial samples. Thus, the industrial sample showed the lowest microbial load compared to the traditional yogurt samples (P < 0.05). Therefore, it is strongly recommended to control the incoming raw milk and observe the sanitary conditions during production, packaging and supply in the production of traditional products. The results of sensory evaluation showed better color and taste for the pasteurized sample and better texture and overall acceptance for the traditional samples. [ABSTRACT FROM AUTHOR]

Purpose: The primary objective of this study was to investigate the viability of Lacticaseibacillus rhamnosus GR-1 (LGR-1) when combined with four prebiotic-rich fruit powders – apple, papaya, mango, and red beetroot – in probiotic yogurt. Additionally, the study aims to assess customer acceptability of the yogurt fortified with these fruit powders through a sensory evaluation using a nine-point hedonic scale. Design/methodology/approach: The yogurt samples, inoculated with the LGR-1 probiotic strain, underwent fermentation at 38 °C for 0, 2, 4 and 6 h. Following fermentation, the samples were stored in a refrigerator at 4 °C for 1, 15 and 30 days. Throughout the study, microbial counts and pH level measurements were performed to assess the viability of LGR-1. A sensory evaluation consisted of 89 participants. A nine-point hedonic scale, ranging from 1 (dislike extremely) to 9 (like extremely), along with a questionnaire were used to assess criteria such as appearance, flavor, texture and overall acceptability of the samples. Findings: All treatments at all time points maintained a minimum viable microbial count of 107 CFU/mL (colony-forming units per mL), which indicated that the addition of fruit powders supported the growth and survival of LGR-1 in yogurt. Treatment 5, fortified with papaya powder, was the only group that exhibited a significant change of microbial count after 30 days of fermentation (p = 0.018). Although there were no statistically significant differences in pH values at the 0- and 2-h time points within each treatment, the pH remained relatively stable after day 15, with an average mean pH of 4.29. Treatment 2 fortified with mango powder obtained the highest overall acceptability score because of its smooth and firm texture as well as mild mango-sweet flavor. Originality/value: This study explored the viability of probiotics and the sensory properties of yogurt fortified with various fruit powders, while also examining the potential prebiotic effects of fruit powders in enhancing overall sensory appeal. The findings suggested that papain may play a role in increasing probiotic viability in yogurt. Given the inconvenience and inaccessibility of fresh fruits and the generally inadequate prebiotic intake, this research addressed the gap in prebiotic consumption by offering novel ideas for health-enhancing dairy products. [ABSTRACT FROM AUTHOR]

Catechin hydrate (CH) is a kind of polyphenol present in many plantsincluding green tea, fruits, red wine and cocoa with very good antioxidant effect. The formulation of CH nanoemulsion increased the bioavailability and stability of catechin, allowing for easier food incorporation and faster absorption by the body. The major goal of the current study was to create a nanoemulsion as a reliable delivery mechanism for catechin hydrate and its incorporation into yogurt to increase its antioxidant activity. In this study, ultrasonication method was used for nanoemulsion preparation. The optimized condition for obtaining reduced droplet size includes two-minute ultrasonication time, 40% ultrasonication amplitude and 1.61:1emulsifier to oil ratio. The CH nanoemulsion's spherical droplet shape was confirmed by transmission electron microscopy(TEM). The chemical characteristics of CH nanoemulsion was studied using FTIR and Raman spectroscopy. The zeta potential value of CH nanoemulsion was-57.56 ± 1.35mV and the size was found to be 78.4 nm.Shelf-life analysis was carried out for yogurt incorporated with CH (YCH) and CH nanoemulsion (YCHN). During shelf-life study, YCHN showed better free radical scavenging activity, stability, and higher sensory assessment than YCH. YCHN had a greater Lactobacillus count (9.3 log CFU/mL) than plain yogurt. Hence, the study suggests catechin hydrate nanoemulsion (YCHN)as an effective technique to reduce bitterness and astringency of catechin for food fortification with better antioxidant activity. Highlights: Catechin hydrate (CH) nanoemulsion was formulated using virgin coconut oil, tween 20 and guar gum. Characterization of Catechin hydrate (CH) nanoemulsion was performed using SEM, TEM, FTIR and Raman Spectroscopy. The yogurt with CH nanoemulsion (YCHN) showed better free radical scavenging activity and stability. YCHN showed superior taste, color, texture, odor and overall acceptability in the sensory evaluation compared to yogurt with plain catechin hydrate (YCH). During storage YCHN had enhanced growth of Lactobacillus compared to YCH. [ABSTRACT FROM AUTHOR]

The current study aimed to produce functional stirred yogurt by incorporating varying amounts of sapote extract (SE) and orange blossom honey. The findings revealed that augmenting yogurt with SE and honey led to a substantial rise in the total phenolic (TPC), total flavonoid compounds (TFC), and antioxidant activity. The physicochemical characteristics showed a favorable shift for the treatments that utilized honey and SE with significant changes observed in total solids (TS), acidity, and pH. In contrast, total protein (TP) and fat content remained unchanged. Sensory analysis indicated that the yogurt augmented with honey and SE had superior flavor, body and texture, and overall acceptability compared to the control sample. However, the addition of SE had an impact on the color of the product. Incorporating honey with SE enhanced the rheological qualities of the product, specifically viscosity and water-holding capacity. There was a decrease in the count of lactic acid bacteria following the addition of honey and SE. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study explores enzymatic hydrolysis as a method of modifying soybean meal (SM). It can reduce the particle size, improve flavor, and convert macromolecules into absorbable nutrients. The purpose is to provide technical information regarding the use of SM. Papain alone, and a combination of papain and acid protease, and a mixture of papain, acid protease, and Lactiplantibacillus plantarum were employed for the enzymatic hydrolysis of SM. RESULTS: Sensory evaluation and nutritional and flavor analyses were performed with yogurt produced after SM enzymatic hydrolysis. The enzymatic hydrolysis improved yogurt quality significantly in comparison with non‐enzymatically hydrolyzed soybean meal yogurt (SMY) by accelerating the decrease in pH and shortening the duration of fermentation. Enzymatic hydrolysis also reduced beany flavors and bitterness and enhanced the aromatic compound, flavor‐related amino acid, and organic acid content, rendering the yogurt more appealing to consumers. Microstructural analysis revealed favorable characteristics that textural and rheological properties of the yogurt produced after enzymatically hydrolyzed SM were improved. CONCLUSION: In this study, the biotechnological approach was used to demonstrate the efficacy of enzymatic hydrolysis in improving the quality and value of SM, promoting the efficient application of SM in the food industry. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of selected plant additives on changes in the content of fatty acids, lipid quality indicators and mineral composition of yogurts produced from cow's milk. The analysis included natural yogurts and yogurts enriched with 10% of chia seeds, hulled hemp seeds, quinoa seeds and oat bran. The fatty acid composition, the content of lipid quality indicators and the content of mineral components was varied in all analyzed yogurts. The plant additives used caused significant (p ≤ 0.05) changes in their fatty acid content, i.e., a significant decrease in the content of saturated fatty acids (SFAs) and short-chain fatty acids (SCFAs), and a significant increase in the content of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). The plant additives used caused significant (p ≤ 0.05) changes in the content of fatty acids, i.e., a significant decrease in the content of saturated fatty acids (SFAs) and short-chain fatty acids (SCFAs), and a significant increase in the content of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). It was shown that additives such as chia seeds and peeled hemp seeds caused the greatest changes in the analyzed yogurts. Yogurts with these additives were characterized by a significant increase in the content of polyunsaturated fatty acids (PUFAs), including n-3 acids, and a more favorable n-6/n-3 ratio. Yogurts with these additives were also characterized by significantly (p ≤ 0.05) lower atherogenic (AI) and thrombogenic (TI) indices and a higher hypocholesterolemia-to-hypercholesterolemia ratio (H/H). The addition of peeled hemp seeds caused the greatest changes in the content of minerals. Yogurts with hemp seeds were characterized by the highest content of all measured macroelements, as well as copper, iron and zinc. In turn, the highest manganese content was determined in the yogurts with the addition of chia seeds. [ABSTRACT FROM AUTHOR]

Egg-based yoghurt (EBY) is a novel yoghurt fermented by lactic acid bacteria with high nutritional and health values, serving as a potential alternative to milk-based yoghurt. However, the hardness, adhesiveness, and water-holding capacity of egg-based yoghurt need to be further improved. In this study, the improvement in EBY quality by gellan gum and its underlying mechanism were investigated. The results showed that gellan gum significantly improved the quality of EBY (p < 0.05). Among the five concentration gradients tested, the EBY supplemented with 0.045% gellan gum exhibited the best quality with the highest sensory score of 83.57. With the increasing amount of gellan gum, hydrogen bonding interactions in the yoghurt significantly increased, while ionic bonding remained unchanged, but hydrophobic interactions and disulphide bonding gradually decreased. Low-field NMR assay results demonstrated that gellan gum significantly raised the amount of strongly bonded water while decreasing the amount of immobile water in the yoghurt. Confocal laser scanning microscopy revealed that EBY with 0.045% gellan gum had a better texture, whereas too much or too little gellan gum led to a coarser structure. In summary, gellan gum altered the water phase state and enhanced the water holding capacity through increased hydrogen bonding interactions, which consequently improved the yoghurt's texture and sensory qualities. This study provides a reference for the development and application of EBY. [ABSTRACT FROM AUTHOR]

This study proposes the use of lyophilized powder of purple-fleshed sweet potato (LP) as a new multifunctional ingredient to improve the identity and quality parameters of stirred yogurts. The physical and chemical properties, color, monomeric anthocyanin content, lactic acid bacteria viability, water retention capacity, microstructure, and texture were evaluated for yogurts enriched with LP at the levels of 2% (YLP2), 4% (YLP4), and 6% (YPL6), stored for 30 days under refrigeration (4 °C). The results indicated that LP provided different intensities and shades of pink coloration to yogurt, in addition to increasing (p < 0.05) the water retention capacity and reducing the water activity. No post-acidification processes were observed during storage. YLP2, YLP4, and YLP6 showed higher stability regarding the number of viable lactic acid bacteria cells compared to the control sample (without enrichment) during storage. Interstitially, adding LP improved the microstructures of the yogurts, promoting more cross-linked networks, with greater uniformity and smaller empty zones, regardless of the level used; in addition, the yogurts (YLP4 and YLP6) were firmer and creamier. These findings demonstrate that LP can be used as a multifunctional ingredient to promote technological/functional improvements, being underscored as a promising natural colorant, stabilizer, emulsifier, and thickener for yogurts. [ABSTRACT FROM AUTHOR]

Aflatoxin M1 (AFM1) is known to be carcinogenic, mutagenic, and teratogenic and poses a serious threat to food safety and human health, which makes its surveillance critical. In this study, an indirect competitive ELISA (icELISA) based on a nanobody (Nb M4) was developed for the sensitive and rapid detection of AFM1 in dairy products. In our previous work, Nb M4 was screened from a Bactrian-camel-immunized phage-displayed library. It exhibits VH-like features, possesses higher thermal stability than monoclonal antibody (mAb 1E6) and tightly binds to AFM1–BSA with a KD value of 2.5 nM. Under the optimal conditions, its half-maximal inhibitory concentration was 0.338 ng/mL, the limit of detection was 0.051 ng/mL, and linearity was noted in the range of 0.168–0.679 ng/mL. Nb M4 displayed almost no cross-reactivity with other mycotoxins. No matrix effect was observed in milk and milk powder samples, and the matrix effect in yogurt samples could be weakened by 2-fold dilution. Furthermore, validation studies in spiked samples (milk, yogurt, and milk powder) resulted in good recoveries of 95.40–111.33%, with a low coefficient of variation (2.89–6.78%). High-performance liquid chromatography was used to evaluate the accuracy and reliability of the developed icELISA, which indicated a satisfactory consistent correlation (R2 = 0.9722). This study highlights the potential of Nb M4 as a promising component for detecting AFM1 in dairy products. [ABSTRACT FROM AUTHOR]

A study was conducted during October, 2022 to June, 2023 at National Dairy Research Institute, Karnal, Haryana, India to evaluate the thermal performance and melting behaviour and the effect of different container materials on energy storage efficiency of phase change materials (PCMs). Paraffin wax, Beeswax and Palm oil was selected for this study and for the container material stainless steel (SS) and polyethylene terephthalate (PET) was selected. The results indicated that PET containers, although slower to heat (100 min), provide a prolonged cooling period (240 min), making them ideal for applications that require delayed heat release. Among the PCMs, Paraffin wax, with a melting temperature of 59.3°C and a melting time of 36 min, was found to be the most suitable for solar thermal applications. Beeswax, while viable, had a higher melting temperature (68.1°C) and a longer melting time (48 min). Palm oil, with a melting temperature of 43°C, was deemed unsuitable. Image analysis confirmed these findings, showing that palm oil had the highest reduction rate in area and perimeter, while all three PCMs displayed favourable roundness values. Based on the results, Paraffin wax in PET containers was identified as the optimal combination for efficient solar energy storage. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the sensorial, physicochemical, rheological, and microbiological properties of yoghurt fortified with Artemisia absinthium leaf powder during refrigerated storage. The valorization of this plant in food industry was realized by the incorporation of its dried leaf powder at various concentrations in order to produce a new functional yoghurt. It is interesting to note that the fortified yoghurt with the lowest Artemisia dose (2%) was the most preferred by the panel. Furthermore, this fortification did not affect the fermentation parameters nor the viability of lactic starter. During storage, the incorporation of Artemisia powder reduced syneresis and improved the microbiological properties of fortified yoghurts. Besides, at the end of storage, it was noted that yoghurt fortified with 2% of Artemisia powder presented the highest consistency (8.98±0.04 Pa sn) and antioxidant activity (60.08±3.61%) when compared to the control yoghurt. Finally, the accelerated shelf-life test showed the efficiency of Artemisia absinthium powder incorporation by increasing the shelf life of yoghurt by about 4 days. [ABSTRACT FROM AUTHOR]

The influence of different strawberry varieties on the microbiological, antioxidant and sensory properties of probiotic yoghurt, containing Bifidobacterium animalis subsp. lactis Bb12, were monitored for 21 days. For this purpose, strawberry pulp (15 %) containing strawberry and sugar in a 1:1 ratio was used in the yoghurt formulation. Higher total phenolic content and ferric reducing antioxidant power (FRAP) were detected in Albion and Camarosa varieties than Rubygem whereas Albion variety had the highest total anthocyanin content (p<0.05). Colour parameters (L*, a*, b*) of probiotic yoghurts differed significantly with the incorporation of strawberry pulp. The viable counts of yoghurt starter bacteria in the experimental yoghurts remained above 7.64 log cfu/g throughout the storage period. Addition of probiotic yoghurt with strawberry pulp enhanced the viability of S. thermophilus and L. bulgaricus depending on the variety of strawberry. A similar effect on B. lactis viability was observed in fruit probiotic yoghurt samples except the 1st day of storage. The counts of B. lactis were above 8.5 log cfu/g throughout the storage period. The highest total phenolic content, antioxidant activity (FRAP) and total anthocyanin content were found in Albion variety added probiotic yoghurt during the storage period. Sensory characteristics of probiotic yoghurt were not generally influenced by the addition of strawberry while sample enriched with Camarosa variety showed the lowest overall acceptability scores on 14th day. [ABSTRACT FROM AUTHOR]

Among the food products, yogurt is very popular due to its distinctive characteristics such as the presence of lactic acid bacteria and nutritional and therapeutic properties. In any case, consumption of high-fat yogurt can endanger health on the one hand, and on the other hand, reducing fat reduces the quality of the product. Therefore, this research was conducted with the aim of investigating the possibility of improving the characteristics of low-fat stirred yogurt using the treatment of microbial enzyme transglutaminase (MTG) and Persian gum (PG). Low-fat stirred yogurt samples were produced using levels of 0, 0.1 and 0.2% (w/v) of PG gum and levels of 0 and 0.015% (w/v) of MTG enzyme. The physicochemical characteristics and color values of the samples were evaluated during 14 days of storage in the refrigerator. Based on the results of this research, the addition of PG and MTG enzyme significantly reduced acidity and syneresis (p<0.05). Furthermore, the addition of gum increased lightness and redness and reduced yellowness. Although the enzyme treatment like PG increased the lightness and redness, it caused an increase in the yellowness of the yogurt. Storage time significantly decreased syneresis and lightness parameters and increased yogurt acidity and redness and yellowness indexes (p<0.001). In conclusion, the results of this research showed that by using transglutaminase enzyme treatment (0.015%) and adding Persian gum (especially 0.2%), low-fat stirred yogurt with acceptable physicochemical characteristics and color can be produced and the quality of low-fat stirred yogurt can be improved. [ABSTRACT FROM AUTHOR]

Yogurt, a widely consumed fermented milk product, is known for its health benefits attributed to the presence of probiotic bacteria. This study explores the impact of starter cultures on the texture and microbiological quality of yogurt. The production involved two types of starter cultures: a commercial culture and an heirloom culture. Various parameters, including chemical analysis of raw milk, yogurt production steps, texture parameter analysis, syneresis, water holding capacity, and microbial analysis, were examined. Statistical analysis was performed to indicate the effect of the type of culture on the production of yogurt. Results indicated that the physicochemical analysis of raw cow milk revealed parameters within recommended quality standards. Significant differences in hardness, gumminess, chewiness, resilience, and syneresis between commercial and heirloom yogurts were found. Microbiological analysis demonstrated higher Lactic acid bacteria counts in commercial yogurt compared to heirloom yogurt. The study provides insights into the influence of starter cultures on textural and microbiological characteristics, emphasizing the importance of standardized production methods for consistent yogurt quality. [ABSTRACT FROM AUTHOR]