Plain Yogurt Research Articles

Sadržaj laktata, ukupnih polifenola i antioksidativna aktivnost odabranih komercijalnih jogurta sa domaćeg tržišta

One of the most popular dairy products worldwide is yogurt, which flavor is highly influenced by lactic acid content. Yogurts with fruit preparations contain polyphenols, secondary plant metabolites with proven antioxidant properties. As there is no data regarding neither lactate nor polyphenol content in commercial yogurts in Serbia, this study aimed to determine lactate and polyphenol levels, as well as antioxidant activity in selected yogurts. A total of 15 plain and 5 fruit yogurts with strawberry preparations were analyzed. Lactate contents were from 0.83 to 1.33%. Three plain yogurts in plastic containers differed in lactate content. There was no difference in lactate content among the same plain yogurts packed in plastic and Tetra Pack containers. Fruit yogurts with strawberry preparations differed in total polyphenol content in the range from 6.84 to 29.11mg GAE/100 g and antioxidant properties were determined by reducing power test (from 0.22 to 0.79) and DPPH assay (from 28.13 to 87.23%), while there was no difference regarding lactate. Our results provided new information about the levels of lactate, total polyphenols and antioxidant activity of selected commercial yogurts available on the Serbian market.

Microbiological Evaluation of Some Fermented Milk Products Retailed for Sale at Local Markets

The consumption of fermented milks by man dates from the beginning of civilization. Fermented milk products are dairy foods that have been fermented with lactic acid bacteria such as Lactobacillus, Lactococcus and Leuconostoc. One hundred random samples of some locally manufactured fermented dairy products including; plain yoghurt, stirred yoghurt, flavored yoghurt, homemade rayeb, and sterilized rayeb (20 of each) were collected from local markets to be examined for their microbiological fitness. The obtained results clarified that the mean value of Coliforms count was 4.10×102 ± 2.0×10, 1.72×102 ± 2.1×10 and 1.65×103 ± 2.69×102 6.10×102 ± 6.4×10 for plain yoghurt, flavored yoghurt and homemade rayeb, respectively. The mean value of S. aureus count was 2.0×10 ± 1.0×10, 6.4×10 ± 4.5×10, 7.23×102 ± 5.4×10 and 1.32×102 ± 2.1×10 stirred yoghurt, flavored yoghurt, homemade rayeb and sterilized rayeb, respectively. Moreover, yeast and molds counts were performed. It could be concluded that the majority of investigated fermented dairy products were contaminated, at different degrees, with Coliforms, S. aureus, yeasts and molds giving an indication of poor sanitary measures adopted during manufacturing, storage, handling, and distribution of these products. In addition, it was observed that homemade rayeb had lower quality than other fermented dairy products.

Physicochemical characteristics, sensory profile, probiotic, and starter culture viability of synbiotic yogurt.

This study aimed to envisage the effectiveness of adding three particular prebiotics (inulin, β-glucan, and Hi-maize) to synbiotic yogurt's physicochemical properties, sensory characteristics, and survivability of the probiotic and starter cultures. The yogurt's gross composition, syneresis, water-holding capacity (WHC), viscosity, sensorial properties, and probiotic and starter cell stability were analyzed. The Lactobacillus delbrueckii subsp. bulgaricus M240-5 and Streptococcus thermophilus M140-2 were employed as yogurt starter bacteria, and Lactobacillus acidophilus LA-5 as probiotic culture. The synbiotic yogurt was formulated with 5% sucrose and 0.7% artificial vanilla flavor. The findings showed that when prebiotic ingredients were added to synbiotic yogurt, it had a significant impact on its sensory qualities, WHC, syneresis, and viscosity when compared to plain yogurt samples. The prebiotics did not affect the pH and titratable acidity of the yogurt samples. Additionally, the prebiotic supplementation did not influence the protein and fat content of synbiotic yogurt (p < 0.05). Prebiotics had an impact on the probiotic cell viability and total viable count (p < 0.05) compared to the plain sample, the 2.5% β-glucan, 1.5% and 2.5% Hi-maize samples had the highest mean viability (8.95 Log CFU/ml). The starter culture ratio remained stable in response to the prebiotic levels. In summary, the production of synbiotic yogurts supplemented with Hi-maize and β-glucan at 1.5% and 2.5%, respectively, is highly advised because these supplementations provide yogurt with acceptable syneresis, viscosity, WHC, and sensory attributes.

Comparative between Ammonia Ion Selective Electrode and Dye Binding Method to study effect of Processing Methods on Protein Content of Plain Yogurt

In this study, two analytical methods were used to determinate the protein, the ammonia ion selective electrode method and dye binding method using orange G and the spectrophotometer at λmax 478 nm by determining the linearity, accuracy, precision, limit of detection and limit of quantitation of each. In comparison, the dye binding method was chosen for its accuracy, repeatability, sensitivity (LOD, LOQ) and speed of performance. After that, it was applied to samples of prepared plain yogurt to study effect of different properties (source, heat treatment and type) of used milk on protein content of plain yogurt.

Quantification of Lactose in Lactose-Freeand Low-Lactose Milk and Milk Products by BIOMILK 300 Lac Biosensor: First Action 2020.09.

In 2018, the AOAC Stakeholder Panel on Strategic Food Analytical Methods approved Standard Method Performance Requirement (SMPR®) 2018.009, for lactose in low-lactose or lactose-free milk, milk products, and products containing dairy ingredients, establishing the minimum recommended performance characteristics to be addressed during the evaluation of methods. Subsequently, AOAC INTERNATIONAL opened a call for methods under the Official Method of AnalysisSM program with the aim of finding a candidate method for confirming compliance with regulatory standards and dispute resolution. A biosensor-based analytical method, BIOMILK 300 LAC, was developed by BIOLAN Microbiosensores S.L. (www.biolanmb.com) to rapidly, easily, and accurately quantify lactose in free or low-lactose dairy products. In response to the AOAC call for methods, BIOLAN performed a single laboratory validation of this method against SMPR 2018.009. Several different matrixes were tested, including: milk, sugary plain yogurt, fruit plain yogurt, flavored liquid yogurt, Greek yogurt, cream, soft cheese, infant formula, café latte, chocolate milk, and high-protein milk shake. Evaluated method parameters included: linearity, selectivity, matrix effect, recovery, accuracy, repeatability, intermediate reproducibility, robustness, reagent lot-to-lot consistency, and stability. The method is based on the use of the Biotest gold electrode together with the BIOMILK 300 biosensor reader, for the quantification of residual levels of lactose in dairy samples via an enzymatic recognition/electrochemical transduction system. Assay linearity, applicability to different matrixes, recovery, and precision demonstrated that the method is fit for purpose. The method proved to be robust, consistent, and stable, under conditions detailed in the Instructions For Use guide. The overall results were within requirements stated by SMPR 2018.009 for low-lactose and lactose-free milk, milk products and products containing dairy ingredients. The BIOMILK 300 LAC method enables the quantification of reduced levels of lactose in less than 5 min, without the requirement for expert technicians, toxic solvents or intricate procedures, maintaining a high degree of precision and accuracy in the results. BIOMILK 300 LAC was adopted as a First Action Official MethodSM by the Expert Review Panel of Low-lactose Methods in April 2020 after rigorous review.

DEVELOPMENT AND CHARACTERIZATION OF PHYSICO-CHEMICAL AND FUNCTIONAL PROPERTIES OF GREEN TEA YOGHURT

The present study aimed at developing a low-fat, low-sugar green tea yoghurt. The final acidities of the green tea and plain yoghurts were similar, but the lactic acid count in green tea yoghurt (5.8*107 cfu/g) was twice of that in the plain yoghurt (2.7*107 cfu/g). This suggested that the tea extract buffered pH lowering during fermentation. Sensorially, the green tea yoghurt was at par acceptable with the plain yoghurt. The total phenolic content of green tea yoghurt was significantly higher (397.9 µg GAE/ mL) than that of the plain yoghurt (81.0 µg GAE/ mL). These polyphenols have proven health benefits like gut health, weight loss, and bone health.

Real-Time Implementation of a Fully Automated Industrial System Based on IR 4.0 Concept

With the advent of modern communication and control strategies, existing industrial enterprises are now being transformed as per Industrial Revolution (IR) 4.0 standards to maximize production rates and monetary gains. To cope with the pace of the modern technological revolution, the Government of Saudi Arabia has launched “Vision 2030”. This research article presents the full automation process of an existing production line at the College of Engineering, King Saud University, as per “Vision 2030” guidelines. Initially, a production line was designed to produce flavored yogurt bottles from a user-defined flavor and plain yogurt mixture. The research project was completed in two phases. During phase I, smart sensing, control, and automation equipment were used to minimize human intervention, the so-called semi-automated mode of operation. A bottle-feeding mechanism and robotic arms were later integrated to eliminate human intervention during the second phase. Moreover, during phase II, Node-RED, Telegram Bots, and a Raspberry Pi 4 controller were used to achieve IoT-based monitoring and control as per Industry 4.0 requirements. A comparative performance analysis was conducted between semi-automated and fully automated modes of operation to demonstrate the benefits of the fully automated operational mode. The performance of the fully automated system was found to be superior in comparison with the semi-automated system.

Evaluation of probiotic yoghurt by the mixed culture with Lactobacillus plantarum A3

Lactic acid bacteria (LAB) fermentation is the simplest and safest way of food preservation, and the use of probiotics in yoghurt could provide dairy products with unique flavors, textures and health benefits. In this study, Lactobacillus bulgaricus, Streptococcus thermophilus, L. reuteri DSMZ 8533 and the potential probiotic strain L. plantarum A3 were used for the milk fermentation. Results found the texture properties such as hardness, consistency, and viscosity of the yoghurt were enhanced in the mixed culture condition. Furthermore, components like amino acid (leucine), vanilla (vanillin), C18:3n6 (unsaturated fatty acids) were also accumulated in L. plantarum A3 fermented yoghurt, which leads to the significant sensory profiling difference compared with the former plain yoghurt. All these results proved L. plantarum A3 is a potential probiotic strain which could enhance the sensory and nutrition profiling of the fermented milk. Future work still needs to be done on the synergistic interaction between the traditional strains and the probiotics during the fermentation process.

An exploratory study using graphic design to communicate consumer benefits on food packaging

Commercial food packages may contain multiple messages. Packaging designers try to integrate all messages into a coherent design. Designers may use text, images or stylistic features, but these mediums may differ in their suitability to communicate specific product benefits. To evaluate the usefulness and effectiveness of these three mediums, we not only obtained consumer evaluations of packaging designs, but we also monitored the designer’s experience during the design process.For three products (orange juice, muesli bar, plain yogurt) we created three consistent packaging designs communicating a single benefit through all three mediums, which was either a [1] health, [2] environmental, or [3] production, sensory or social claim. Subsequently, we developed inconsistent packages communicating three different messages through the three mediums. In an online survey, each of the 18 package variants was evaluated by 59–92 participants.Dummy regression analysis suggested that verbal claims had positive effects in communicating healthiness and environmental friendliness but elicited a negative tendency for sensory properties. The images we used indicated a positive effect for communicating worker conditions, but a negative effect for healthiness. Our stylistic elements suggested a positive effect for sensory appeal, but tended to have negative effects for environmental aspects. As regards designer dilemmas, we noticed that some images (e.g., in the medical domain) required specific graphic styles to make them acceptable for commercial use. Our findings suggest that consumers can handle multiple packaging messages, but finding an optimal configuration remains a design challenge.

Preliminary study on kinetics of pyroglutamic acid formation in fermented milk

Pyroglutamic acid (pGlu) influences the aromatic and sensory properties of foods and has several benefits for human health. The presence and kinetics of pGlu formation in fermented milk samples were investigated from a chemical point of view. Plain yoghurt, kefir and other probiotic fermented milk products available on the market were analysed to quantify lactic acid and pGlu. The pGlu concentrations in fermented milks ranged from 51.65 to 277.37 mg 100 g−1 dry matter. Laboratory-scale fermented milk was produced, and samples were taken at different times of fermentation and storage to construct the kinetics curve. At the beginning of the fermentation process, pGlu was already present in UHT milk (188.69 mg 100 g−1 dry matter) used to elaborate fermented milk, and its content increased not only during fermentation but during storage as well, reaching up to 403.56 mg 100 g−1 dry matter after 30 days.

Development of Freeze-Dried Red Dragon Fruit Yoghurt Containing Probiotics

Yoghurt, a product prepared by fermentation of milk with bacterial cultures consisting of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, has been popular for a long time, however, dehydrated yogurt is still uncommon. Freeze drying is well-known as an effective method to preserve the nutritional and sensory characteristics of the food product compared to other dehydration ways. This study developed a protocol to produce freeze-dried yoghurt fermented by commercial probiotic starter culture containing betacyanin – a bioactive component from red dragon fruit on laboratory scale. The freeze-dried red dragon yoghurt was produced by the following steps: (1) plain yoghurt preparation: Milk with 12% milk dry matte was heated at 95oC for 5 min, cooled down to 42oC, followed by the addition of commercial probiotic bacteria starter, then fermented for 3 hours until the pH reached to 4.6 and the milk coagulated (2) obtained yoghurt was mixed with 30 % red dragon fruit, molding in the tray (3) Freeze at -20oC and freeze-dried (4) packaging to obtain the final product. Betacyanin – well-known as a bioactive compound from red dragon fruit of the obtained products and viable bacteria remained during 30 days storage at room temperature.

Optimization of Fermentation Process and Evaluation of Quality and Flavor of Quinoa Yogurt Produced by Mixed Lactic Acid Bacteria

In this study, Streptococcus thermophilus 6063, Lactobacillus bulgaricus 6064 and Bifidobacterium animalis B15 were selected to ferment quinoa yogurt, and the puffed quinoa powder and milk were used as raw materials. Fermentation process was optimized by orthogonal experiment on the basis of single-factor experiments. And the effects of puffed quinoa powder on quality and flavor of yogurt were also evaluated. Results indicated that the optimal fermentation conditions were as follows: Streptococcus thermophilus: Lactobacillus bulgaricus: Bifidobacterium animalis=2:1:2, inoculation amount 2%(v/v), quinoa powder 5%(w/v) and fermentation temperature 41 ℃. Under these conditions, quinoa yogurt had good flavor, and the total viable number of lactic acid bacteria reached 109 CFU/mL. From the beginning of fermentation to the end of storage for 21 days, the titratable acidity of quinoa yogurt was always higher than that of plain yogurt, but the total number of viable lactic acid bacteria was opposite trend. Compared with plain yogurt, the contents of protein, polyphenols and flavonoids in quinoa yogurt increased respectively by 88.67%, 166.67%, and 284.62%. The contents of lactic acid, formic acid, acetic acid and pyruvate in quinoa yogurt were 5.80, 1.42, 0.11 and 0.01 mg/g, respectively. 74 kinds of volatile substances were detected in quinoa yogurt by GC-MS. Compared with pure yogurt, 30 kinds of new volatile substances were discovered. The research results would provide a technology support for further research and new product development of quinoa yogurt, promoting the application and development of quinoa.

Co-Fermentation by Lactobacillus brevis B7 Improves the Antioxidant and Immunomodulatory Activities of Hydroponic Ginseng-Fortified Yogurt.

The development of convenient and accessible health-functional foods has become an area of increased interest in recent years. Probiotics, ginseng, and yogurts have been recognized as representative nutraceutical products. To improve the functionality of yogurts, co-fermentation was performed during yogurt preparation. Four kinds of yogurt were prepared using a combination of probiotic Lactobacillus brevis B7 and hydroponic ginseng based on plain yogurt. The fundamental characteristics of yogurts, including pH, titratable acidity, microbial counts, color, and physicochemical properties, were determined. To assess functionality, four different antioxidant assays and real-time PCR analysis using RAW 264.7 cells were performed. Finally, sensory evaluation was conducted to evaluate customer preference. Hydroponic ginseng supplementation influenced pH, solid content, lightness, and yellowness. However, probiotic supplementation did not affect most factors except pH. In functionality analysis, the yogurt co-fermented with probiotics and ginseng showed the highest antioxidant activity and gene expression levels of the immune-related factors TNF-α and iNOS in RAW 264.7 cells. Although ginseng supplementation received poor acceptance because of its color and flavor, these attempts were considered beneficial despite the risk. Overall, co-fermentation within a short yogurt preparation time presented the potential for improvement of functionality. These findings suggest a range of feasibility for the development of attractive nutraceutical products.

Homemade Modification of Salad Dressings to Reduce Their Erosive Potential.

To investigate the possibility of reducing the erosive potential of salad dressings by adding yoghurt. Two hundred enamel samples from bovine teeth were allocated to 20 groups (n = 10). Three modified commercially available balsamic dressings (addition of 10%, 20%, 50% yoghurt or 8.8 mM calcium chloride) and two homemade salad dressings with and without modifications were tested. Enamel samples were eroded for 2 min, rinsed for 30 s with tap water and finally abraded (20 brushing strokes with toothpaste slurry). After 40 of these cycles of erosion/abrasion, the dental hard tissue loss was determined by contact profilometry. For commercially available salad dressings, modification yielded a statistically significant decrease in enamel wear. The exception was Anna's Best Dressing Balsamico modified with 8.8 mM calcium chloride, for which no reduction was found compared with the unmodified dressing. For all homemade dressings, a significant reduction was observed when modified with 20% yoghurt. However, when only 10% yoghurt was added to the homemade dressings, an increase of the erosive potential was observed compared to the unmodified dressing. The study shows that increasing the calcium concentration only with calcium chloride in commercially available salad dressings did not show predictable outcomes to reduce erosion. However, mixing 20% plain yoghurt into the dressings reduced the erosive potential statistically significantly.

Traceability of sweeteners in soy yogurt using linear discriminant analysis of physicochemical and sensory parameters

The present study was aimed to design and develop the consumer-accepted soy yogurt using different sweeteners and investigate the possibility of tracing these sweeteners by implementing a classification algorithm. The effects of three types of sweeteners on the physicochemical properties, sensory properties, and prediction of sweeteners in soymilk-based yogurt were investigated using linear discriminant analysis (LDA). Yogurts were prepared by inoculating lactic acid cultures into soymilk containing 0.3% gelatin, one of the selected sweeteners [sucrose, honey, and sucralose (an artificial sugar)], and strawberry flavor. Freshly prepared soy yogurts were then analyzed for their physicochemical and sensory characteristics. The results revealed that the honey samples had a higher protein content (4.69%–4.71%) compared to that in plain yogurt (3.83%). Soy yogurts containing the sweeteners had a relatively reduced fat content, with the lowest fat content exhibited by the honey samples (1.88%–1.91%). Furthermore, the addition of sweeteners resulted in final products with varying ash content and total soluble solids (TSS). In contrast, the least effect was found on lactic acid and pH. The overall sensory results revealed that the strawberry flavored soy yogurt with honey as sweetener could attain acceptable quality upon processing. LDA with two components based on the partial chemical composition of soy yogurts could identify the sweetener source in unknown soy yogurt samples. The discriminatory ability of the LDA model was further validated using unknown soy yogurt samples to predict the sweeteners, and an accuracy level ranging from 80% to 100% was attained in 1000 test runs. Moreover, the model could distinguish the presence of artificial sweeteners from the other sweeteners in the samples with 100% accuracy.

Generating community measures of food purchasing activities using store-level electronic grocery transaction records: an ecological study in Montreal, Canada.

Geographic measurement of diets is generally not available at areas smaller than a national or provincial (state) scale, as existing nutrition surveys cannot achieve sample sizes needed for an acceptable statistical precision for small geographic units such as city subdivisions. Using geocoded Nielsen grocery transaction data collected from supermarket, supercentre and pharmacy chains combined with a gravity model that transforms store-level sales into area-level purchasing, we developed small-area public health indicators of food purchasing for neighbourhood districts. We generated the area-level indicators measuring per-resident purchasing quantity for soda, diet soda, flavoured (sugar-added) yogurt and plain yogurt purchasing. We then provided an illustrative public health application of these indicators as covariates for an ecological spatial regression model to estimate spatially correlated small-area risk of type 2 diabetes mellitus (T2D) obtained from the public health administrative data. Greater Montreal, Canada in 2012. Neighbourhood districts (n 193). The indicator of flavoured yogurt had a positive association with neighbourhood-level risk of T2D (1·08, 95 % credible interval (CI) 1·02, 1·14), while that of plain yogurt had a negative association (0·93, 95 % CI 0·89, 0·96). The indicator of soda had an inconclusive association, and that of diet soda was excluded due to collinearity with soda. The addition of the indicators also improved model fit of the T2D spatial regression (Watanabe-Akaike information criterion = 1765 with the indicators, 1772 without). Store-level grocery sales data can be used to reveal micro-scale geographic disparities and trends of food selections that would be masked by traditional survey-based estimation.

Non-enzymatically hydrolyzed guar gum and orange peel fibre together stabilize the low-fat, set-type yogurt: A techno-functional study

A combined integration of partially hydrolysed guar gum (PHGG) and orange peel fibre (OPF) into low-fat, set-type yogurt was explored. PHGG was produced using steam hydrolysis assisted by ultra-sonication while OPF (coarse fraction) was prepared from the dried orange peels. PHGG and OPF were further studied for their structural, physical, physico-chemical and rheological characteristics. PHGG exhibited shear thickening and Newtonian behaviour while, OPF showed shear thickening and non-Newtonian behaviour. Size determination of PHGG and OPF adjudged them as fine and coarse fibres, respectively. Four groups of yogurt were prepared by varying the concentration of PHGG (0–0.5% w/v) while, OPF (0.1% w/v) was kept constant. PHGG and OPF formed complimentary fibre networks which stabilized the yogurt gel by acting as filler and bridging agent, respectively. PHGG 0.25% (w/v) + OPF fortified yogurt presented superior rheological, textural and physico-chemical properties in comparison to plain and other fortified yogurts during storage (28 days, 4 °C). Scanning electron microscopy showed that fibre fortified yogurts had more structured and compact casein network as compared to plain yogurt. Thus, fortification with a combination of dietary fibres can not only improve the techno-functional properties of low-fat, set-type yogurt but also provide health benefits of dietary fibre and phytochemicals.

Microbial, physiochemical and functional properties of probiotic yogurt containing Lactobacillus acidophilus and Bifidobacterium bifidum enriched by green tea aqueous extract.

In this study, the effect of aqueous extract of green tea on the viability of probiotic bacteria including Lactobacillus acidophilus and Bifidobacterium bifidum and the sensory and physicochemical and functional properties of synbiotic yogurt was investigated during 4 weeks of storage. L. acidophilus and B. bifidum counts did not significantly change in yogurt containing 0.5% and 1% of the extract during storage. Also, the addition of the extract to yogurt highly increased the phenolic compounds, since the amount of phenolic compounds in yogurt containing 0.5% and 1% extract was 660 and 1,123 mg gallic acid/kg, respectively. In addition, a significant increase in the antioxidant activity of yogurt containing green tea extract was observed in comparison with the control. The amount of antioxidant activity increased during 4 weeks of storage, which reached to 4,193 and 7,337 mg BHT eq./kg in probiotic yogurt containing 0.5% and 1% extract, respectively. The acidity increased during 4 weeks of storage, while the pH decreased. Addition of the extract significantly increased the acidity of probiotic yogurt compared with the control (p < .05). In addition, in all studied groups, an increase in syneresis was observed during the study, and the syneresis was greater in yogurt containing aqueous extract of green tea, compared with the control group. Although adding the green tea extract to probiotic yogurt impaired taste, texture, and appearance compared with the plain yogurt, the overall acceptability of these samples was yet above the acceptable level. In conclusion, the results of the study showed that the addition of aqueous extract of green tea increased the antioxidant properties and the amount of phenolic compounds in yogurt, while the viability of probiotic bacteria was not changed. Therefore, the simultaneous use of green tea extract and probiotics in yogurt is recommended as an effective functional food formulation.

Enhancement of probiotics viability and lactic acid production in yogurts treated with Prangos ferulaceae and Carum copticum plant extracts

This study aimed to investigate the effects of two plant extracts, Prangos ferulaceae, and Carum copticum, on the growth and survival of Lactobacillus plantarum and Bifidobacterium animalis subsp. lactis strains in 4 types of yogurt prepared using milk of cow, sheep, goat, and camel. The conditions of the yogurt probiotics were evaluated through the colony count method after 0, 7, 14, and 21 days with the lactic acid produced in each sample assessed using gas chromatography analysis after 21 days. The sensory characteristics of different yogurts were evaluated 7 days after production. We also examined the effect of casein and whey protein derived from four mentioned milk on the growth of probiotic bacteria in MRS agar medium. According to the results, the presence of both extracts significantly enhanced the survival of probiotics in each yogurt. The sheep yogurt treated with Prangos ferulaceae contained 9.7 log CFU/mL of Lactobacillus plantarum. Further, the lactic acid content of all samples was considerably higher than the controls. Also, Prangos ferulaceae could raise the lactic acid generated by Lactobacillus plantarum to more than 5 g/L of sheep yogurt. Notably, whey protein derived from sheep milk had the most positive effect on the growth of the mentioned bacteria. On the other hand, bovine casein showed a significant effect on decrease in growth of probiotics bacteria. The sensory analysis also determined that the yogurt samples supplemented with Prangos ferulaceae were more preferable than plain yogurt samples.

Clean Label Trade-Offs: A Case Study of Plain Yogurt.

Consumer demand for clean label has risen in recent years. However, clean label foods with simple and minimalistic ingredient lists are often expensive to produce and/or may possess less desirable sensory qualities. Accordingly, understanding consumer preferences regarding the clean label trend would be of great interest to the food industry. Here we investigate how ingredient lists and associated sensory quality descriptions may influence consumer preferences using a hypothetical choice experiment. In particular, we test the impacts of four common stabilizers (carrageenan, corn starch, milk protein concentrate, and pectin) and textural characteristics on preferences and willingness to pay for plain yogurt. A total of 250 yogurt consumers participated in the study. The results of a mixed logit analysis suggest that clean labeling significantly increases the likelihood of consumer choice, while poor texture reduces consumer choice. More importantly, the negative impact of poor texture seems to be less significant for clean label yogurts compared to that for yogurts with longer ingredient lists. Among all stabilizers, corn starch in particular has a significant negative impact on consumer choice. The estimated average consumer willingness to pay for clean labels is between $2.54 and $3.53 for 32 oz yogurt formulations. Furthermore, clean labels minimize the negative impact of textural defects with consumers willing to pay an estimated premium of $1.61 for the family size yogurt with a simple ingredient list. Results of latent class modeling reveal two classes of consumers with similar patterns of demand who prefer clean labels and, on average, would rather purchase a yogurt with a textural defect than opt out of purchasing a yogurt entirely. Implications for the food industry are discussed.