Microbial, physical and sensory properties of yogurt supplemented with lentil flour

Formulations and assessments of structure, physical properties, and sensory attributes of soy yogurts: Effect of carboxymethyl cellulose content and degree of substitution

Soy yogurts present challenges, including absence of tender and slipperiness mouthfeel, and poor stability. This study aimed to investigate the impacts of carboxymethyl cellulose (CMC) with degrees of substitution of 0.7 (CMC0.7) and 1.2 (CMC1.2) at concentrations ranging from 0 % to 1.1 % on the stability, microstructure, rheology, tribology, and mouthfeel of soy yogurts. As the CMC concentration increased from 0 % to 0.3 %, soy yogurts displayed a coarser microstructure, decreased stability, and increased gel strength. As the concentration of CMC further increased from 0.5 % to 1.1 %, soy yogurts exhibited trends of a smoother microstructure, increased stability, and softer gel strength. Notably, soy yogurts with CMC0.7 demonstrated a superior water holding capacity (WHC) than soy yogurts with CMC1.2. Tribological measurements indicated that soy yogurts with CMC0.7 at a 0.7 % concentration had the lowest coefficient of friction (COF) value among most sliding speeds, showing a 23 % reduction compared to soy yogurts without CMC at a sliding speed of 10 mm/s. Moreover, sensory evaluation showed that soy yogurts with CMC0.7 at a 0.7 % concentration had the highest total score in mouthfeel evaluation. Therefore, the addition of CMC0.7 within the concentration range of 0.5 % to 1.1 % may produce stable and delicate yogurts.

Effect of red beet cooking water on yoghurt's physico-chemical, textural and antioxidant characteristics

This study aimed to evaluate the effect of red beet cooking (Beta vulgaris L.) water on the quality properties of yoghurts prepared with different levels (2, 4, 8, and 10% w/w) compared to the nature sample. Results showed a decrease in pH value and an increase in titratable acidity (TA), fat content, and dry matter with the increasing red beet cooking water concentration. Consumer test revealed that incorporating 4% (w/w) red beet cooking water into yoghurt influences the product's overall acceptability compared to the other formulations. The addition of red beet cooking water at the level of 4% induces significant increase in gel firmness with a decrease in syneresis compared to the control sample. The lightness and yellowing of the product decreased while the redness increased. Furthermore, the effect of red beet cooking water addition was significant (p < 0.05) on total phenolic contents (0.369 ± 0.024) as well as antioxidant activity (0.140 ± 0.008). Beet cooking water may be a potential ingredient in the formulation of functional products.

Combination of Milk and Plant Proteins to Develop Novel Food Systems: What Are the Limits?

In the context of a diet transition from animal protein to plant protein, both for sustainable and healthy scopes, innovative plant-based foods are being developing. A combination with milk proteins has been proposed as a strategy to overcome the scarce functional and sensorial properties of plant proteins. Based on this mixture were designed several colloidal systems such as suspensions, gels, emulsions, and foams which can be found in many food products. This review aims to give profound scientific insights on the challenges and opportunities of developing such binary systems which could soon open a new market category in the food industry. The recent trends in the formulation of each colloidal system, as well as their limits and advantages are here considered. Lastly, new approaches to improve the coexistence of both milk and plant proteins and how they affect the sensorial profile of food products are discussed.

Optimizing the effect of plant protease on different properties of analog cheese containing functional corn leachate

Cheese is produced in different flavors, textures, and forms by coagulating the milk protein casein. This study investigated the possibility of producing analog cheese by using corn steep liquor with Withania coagulans extract (WCE) and adding Eryngium planum extract (EPE) and Origanum majorana extract (OME) as functional ingredients. Different physicochemical, microbial, texture, and sensory properties of the samples were evaluated. The results obtained for moisture factor, fat, ash, water content, L*, b*, firmness, overall form, Lactobacillus and overall acceptance of the effect of all three process variables, pH, and acidity show that only the effect of WCE and OME is significant. Also, the protein of the samples was significant only on WCE and EPE (p < .001). The results showed that an increase in the levels of independent variables resulted in an increase in the amount of moisture, ash, protein, Lactobacillus, and b* and a decrease in fat, syneresis, texture properties, coliform, and lightness. Evaluation of the overall acceptance showed that consumer acceptance increased with the increase in WCE, but it initially increased and then decreased with the increase in EPE and OME levels. Finally, the samples containing 1.5% WCE, 1% EPE, and 0.5% OME were chosen as the optimized ones.

Bioactive Compounds Extracted from Saudi Dates Using Green Methods and Utilization of These Extracts in Functional Yogurt

The bioactive compounds of four Saudi date flesh extracts (Ambara (AF), Majdool (MF), Sagai (SF), and Sukkari (SKF)) prepared using different extraction methods-namely, supercritical fluid extraction (SFE), subcritical CO₂ extraction (SCE), and Soxhlet extraction (SXE)-were evaluated. A total of 19 bioactive compounds were detected in extracts prepared using SFE and SCE methods, whereas less than 12 compounds were detected in extracts obtained using the SXE method. Both the date variety and extraction method affected the phenolic profile of date flesh extract (p ≤ 0.05). The apparent viscosity, surface color, and bioactive properties of yogurt were affected by both date flesh extracts and storage duration in varied magnitudes (p ≤ 0.05). The incorporation of date flesh extracts into yogurt formulations increased the total phenolic content (TPC), DPPH antiradical activity, viscosity, and redness (a*) and decreased the lightness (L*) and yellowness (b*) of the developed product (p ≤ 0.05). The elongation of storage time progressively (p ≤ 0.05) reduced the pH, TPC, DPPH antiradical activity, bacterial counts, and L* and b* values and increased the acidity, syneresis, viscosity, and a* values with few exceptions. Date flesh extracts can improve the health quality of yogurt without major influence on the sensory attributes while stored at 4 °C.

Effect of Ethanol on Preparation of Konjac Emulgel-Based Fat Analogue by Freeze-Thaw Treatment

In the current study, a method using ethanol to modulate the texture properties of konjac gel during freeze-thaw process was used to prepare konjac emulgel-based fat analogue. A certain amount of ethanol was added to konjac emulsion, heated to form a konjac emulgel, then frozen at −18 °C for 24 h, and finally thawed to obtain konjac emulgel-based fat analogue. The effects of different ethanol contents on the properties of frozen konjac emulgel were explored, and data was analyzed by one-way analysis of variance (ANOVA). The emulgels were compared with pork backfat in terms of hardness, chewiness, tenderness, gel strength, pH, and color. The results showed that the konjac emulgel with 6% ethanol had similar mechanical and physicochemical properties to pork backfat after freeze-thaw treatment. The results of syneresis rate and SEM showed that adding 6% ethanol could not only reduce the syneresis rate, but also effectively weaken the damage to the network structure caused by freeze-thaw treatment. The pH value of konjac emulgel-based fat analogue was between 8.35–8.76, and the L* value was similar to that of pork backfat. The addition of ethanol provided a new idea for the preparation of fat analogues.

Quinoa flour as a skim milk powder replacer in concentrated yogurts: Effect on their physicochemical, technological, and sensory properties

Milk standardization with solids (i.e., nonfat milk solids, MSNF) for yogurt manufacture is traditionally achieved by the addition of skim milk powder (SMP). However, the addition of SMP to milk‐based yogurt increases lactose content and decreases both protein content and gel firmness. Thus, in this work, quinoa flour (QF; 0%, 25%, 50%, 75%, and 100% w/w) was used to replace SMP in concentrated yogurt. The physicochemical, textural, and sensory properties and microstructure of the yogurt were evaluated during cold storage. Generally, protein content, water‐holding capacity, and L* value decreased, while syneresis, textural attributes, and viscosity increased with increasing QF content. The substitution of high levels of QF (>25%, w/w) for SMP led to significantly shorter fermentation times, as compared to the control sample. The scanning electron microscopy observations showed significant changes in the yogurt microstructure as a consequence of QF replacement. Samples with 25% (w/w) substitution of QF and control had the highest scores in overall acceptance. According to the results, QF could be applied as an interesting raw material for concentrating the milk‐based yogurt at substitution level of 25% (w/w).

Formulation and characterization of yogurt prepared with enzymatically hydrolyzed potato powder and whole milk powder

This study highlights the optimization of a suitable amount of enzymatically hydrolyzed potato powder (EHPP) with whole milk powder (WMP) to produce a quality yogurt. The yogurt was prepared with different levels of EHPP (0, 10, 15, 20, 25, 35 and 50% w/w) with WMP and evaluated after 24 h at 4 °C. The resulted product was analyzed on the basis of physicochemical, sensory, texture, antioxidant activity and microbiological analysis. The prepared yogurt showed a significant (p < 0.05) decrease in pH, protein and fat while acidity, moisture and ash contents were increased compared with control yogurt. In addition, textural parameters like hardness and adhesiveness were decreased while no significant (p < 0.05) change was found in springiness and cohesiveness. Moreover, color parameters such as L ^* and a ^* values decreased while b ^* values were increased. The current study suggested that the yogurt sample supplemented with 25% EHPP of WMP certainly improved the physicochemical, texture, microstructure, color, antioxidant and sensory properties of yogurt with EHPP. The prepared yogurt with EHPP provided an excellent flavor, satisfying sweetness, and homogeneous texture. The yogurt prepared from the EHPP presented potential industrial applications.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05112-6.

The Effect of Banana Fiber and Banana Peel Fiber on the Chemical and Rheological Properties of Symbiotic Yogurt Made from Camel Milk

Functional foods play an important role in human health by prevention of disease. A variety of functional foods are produced around the world. Recently, the consumption of dairy products containing probiotic bacteria and prebiotics (synbiotic) has increased. Yoghurt is the most common fermented dairy product. Various compounds are used to enrich yoghurt. One of these compounds is dietary fiber. Since the peel of fruits has a significant amount of fiber and is mainly disposed of as solid waste, so using the peel of fruits to extract fiber can not only solve environmental problems but also produce a cheap and useful source that leads to the production of dietary fiber. In this study, the effect of banana fiber and banana peel fiber at different concentrations (0, 0.2, 0.5, and 1%) on the chemical and rheological properties of synbiotic yogurt prepared from camel milk was investigated. The result showed that with increase of the amount of both fibers, pH, hydration, surface tension, overall acceptability, color, and flavor of the samples decreased significantly, but the viscosity, survival of probiotic bacteria (Lactobacillus casei and Lactobacillus gasseri), and texture acceptance increased significantly (p < 0.05). In conclusion, these fibers were able to reduce the syneresis of yogurt, which is one of the biggest disadvantages of yogurt, and help to increase health.

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.

Functional Tea-Infused Set Yoghurt Development by Evaluation of Sensory Quality and Textural Properties

In the present study, the potential to design natural tea-infused set yoghurt was investigated. Three types of tea (Camellia sinensis): black, green and oolong tea as well as lemon balm (Melissa officinalis L.) were used to produce set yoghurt. The sensory quality (using Quantitative Descriptive Profile analysis and consumer hedonic test) and texture analysis, yield stress, physical stability and colour analysis were assessed to describe the profile of the yoghurt and influence of quality attributes of the product on the consumer acceptability of infused yoghurts in comparison with plain yoghurt. Among the analyzed plant additives for yoghurt, addition of 2% oolong tea to the yoghurt allows a functional food to be obtained with satisfactory texture and sensory properties, accepted by consumers at the same level as for control yoghurt. Both types of yoghurt were also characterised by high consumer willingness to buy, which confirms the legitimacy of using oolong tea as a natural, functional yoghurt additive that improves the sensory quality of the product. The high overall quality of yoghurt with oolong tea in comparison to other plant extracts was associated with the intensive peach flavour and odour, nectar and sweet odour and flavour, and the highest creaminess and thickness. That was confirmed by principal component analysis (PCA) where the overall sensory quality of yoghurts was mainly positively correlated with peach flavour and odour, sweet odour and yoghurt odour, while it was negatively correlated with herbs flavor and odour, and green tea flavour and odour. The sensory profile confirmed no differences in textural profile between plain yoghurt and the tea-infused one measured in the mouth, which corresponds to the result of textural properties such as firmness and adhesiveness.

Effect of anthocyanin-absorbed whey protein microgels on physicochemical and textural properties of reduced-fat Cheddar cheese

Reduced-fat foods have become more popular due to their health benefits; however, reducing the fat content of food affects the sensory experience. Therefore, it is necessary to improve the sensory acceptance of reduced-fat foods to that of full-fat equivalents. The aim of this study was to evaluate the effect of adding whey protein microgels (WPM) with an average diameter of 4 μm, or WPM with adsorbed anthocyanins [WPM (Ant)] on the textural and sensory properties of reduced-fat Cheddar cheese (RFC). Reduced-fat Cheddar cheese was prepared in 2 ways: (1) by adding WPM, designated as RFC+M, or (2) by adding WPM (Ant), designated as RFC+M (Ant). For comparison, RFC without fat substitutes and full-fat Cheddar cheese were also prepared. We discovered that the addition of WPM and WPM (Ant) increased the moisture content, fluidity, and meltability of RFC, and reduced its hardness, springiness, and chewiness. The textural and sensory characteristics of RFC were markedly inferior to those of full-fat Cheddar cheese, whereas addition of WPM and WPM (Ant) significantly improved the sensory characteristics of RFC. The WPM and WPM (Ant) showed a high potential as fat substitutes and anthocyanin carriers to effectively improve the acceptance of reduced-fat foods.

The impact of quinoa flour on some properties of ayran

In this study, some physical, chemical, microbiological, and sensory properties of ayran produced from quinoa flour addition at different ratios (0.1, 0.2, 0.3, and 0.4%, w/v) were investigated. The effect of quinoa addition and storage time on pH, titration acidity, serum separation, L values and microorganism counts were statistically significant (p < .05). The counts of Streptococcus salivarus subsp. thermophilus and Lactobacillus delbruecki subps. bulgaricus had a wide range between 7.13 and 7.52 log CFU/mL and 3.62 and 3.98 log CFU/mlL At the end of the storage, the general appreciation score of the sample containing 0.2% quinoa flour was found to be higher than the other samples.

Effect of faba bean and chickpea mucilage incorporation in the structure and functionality of kefir

This investigation aimed to investigate the viability of kefir enrichment with mucilage extracted from faba bean and chickpea. Four formulations of kefir were studied: fermented milk (control), milk with 3% of faba bean mucilage, milk with 3% of chickpea mucilage and milk with 3% of inulin from artichoke (as prebiotic control). Kefirs were evaluated during 28 days’ storage time at refrigerated temperature. Microbial viability, physicochemical properties (total titratable acidity, syneresis and pH), rheological properties (flow and dynamic shear rheology) and consumer’s acceptability were evaluated. The number of bacteria significantly increased during storage period in all the formulations. The pH decreases during storage whereas total titratable acidity increased as was expected. Kefir supplemented with mucilage showed slightly lower but not significantly different sensory acceptability scores in comparison to the control. The novel mucilage ingredients could be prebiotic source for improving kefir quality.

Comprehensive Evaluation of Microbiological and Physicochemical Properties of Commercial Drinking Yogurts in Korea

Most consumers consider yogurt to be a healthy food because it contains probiotic microorganisms. Although a plethora of commercially produced yogurts exists, nutritional and functional aspects of the commercial yogurts have not been well characterized. In this study, the microbiological and physicochemical properties of popular drinking yogurts in Korea were extensively characterized. The viability of lactic acid bacteria, including lactobacilli and bifidobacteria, varied between yogurt samples. These lactobacilli and bifidobacteria showed effective antimicrobial activities against foodborne pathogenic bacteria. Unlike the titratable acidity and pH, the soluble solids content varied between yogurt samples. All the yogurt samples contained high levels of potassium (average 143.53 mg/100 g) and calcium (average 133.92 mg/100 g), as well as phosphorus and sodium. Lactose, fructose, and glucose were the major sugar components in most yogurt samples, whereas the levels of sucrose and maltose were relatively low. Among several organic acids analyzed in the yogurt samples, lactic acid (average 767.67 mg/100 g) and citric acid (average 170.91 mg/100 g) were the most predominant. Taken together, this study provides preliminary information about the nutritional and functional characteristics of commercially available drinking yogurts.

Numerical optimization of probiotic Ayran production based on whey containing transglutaminase and Aloe vera gel

The purpose of this study was to optimize the functional properties of probiotic Ayran. Two-level fractional factorial design with four center points was used to investigate the effect of five independent variables including, reconstructed whey protein (70-90% of milk), salt (0.5-1 g/100 g), Aloe vera gel (0-30 g/100 g), transglutaminase enzyme (0-14 unit/100 g) and storage time (1-21 days). The viability of Lactobacillus acidophilus La-5 and other physicochemical properties such as pH, acidity, viscosity, sedimentation, and color were modeled and then optimized using desirability function method. Results showed that reconstructed whey protein and Aloe vera gel significantly affected the viability of L. acidophilus La-5 and other physicochemical properties (p < 0.05). The viability of L. acidophilus La-5 and viscosity decreased by increasing of whey protein percentage from 70 to 90. Maximum L. acidophilus La-5 count was observed in samples with a minimum level of whey protein and maximum level of Aloe vera gel. Milk replacement with whey protein up to 90% caused to decrease acidity and viscosity significantly but sedimentation increased (p < 0.05). Optimum condition for production of functional Ayran determined as follow: Aloe vera gel concentration: 25.7%, reconstructed whey protein: 70%, salt: 0.58% and transglutaminase enzyme: 5 unit/100 mL.

Powdered yoghurt produced by spray drying and freeze drying: a review

Abstract Yoghurt is one of the dairy products most consumed worldwide but dehydrated yoghurt is still uncommon. Considered a nutritious food, yoghurt powder could be used as an ingredient or supplement in juices, cookies, ice cream and dairy beverages. Spray drying and freeze drying are the methods most widely used to dehydrate dairy products, and the process conditions are directly associated with the production costs and value of the final product. Due to osmotic and thermal stress during dehydration, it is often necessary to incorporate agents such as carriers, thermal protectants, cryo-protectants and stabilizers in order to improve the process yield, preserve nutrients and even facilitate rehydration of the product. Thus the present review presents the technologies available to obtain yoghurt powder, including the processes, drying agents, drying rates, rehydration conditions and survival of the lactic acid bacteria.

Application of new insoluble dietary fibres from triticale as supplement in yoghurt - effects on physico-chemical, rheological and quality properties

BACKGROUND

The need to increase the daily intake of dietary fibres opens a new chapter in the research of functional foods enriched with fibres. The potential application of an innovative product - insoluble dietary fibres from triticale in yoghurts - was deployed by characterising their food application and evaluating physico-chemical, rheological and sensory properties and was the aim of this research.

RESULTS

Detailed characterisations of these fibres are presented for the first time and showed very good hydration properties, optimal pH (slightly acidic), optimal chemical composition, high antioxidant capacity which was proven by phenolics contents. Besides, these fibres showed negligible calorific value, with no phytates and high antioxidant capacity, mainly from ferulic acid. Therefore they could be successfully added to yoghurt. Enrichment of yoghurt having different milk fat content (1.5 and 2.8% w/w) with triticale insoluble fibre (1.5% and 3.0% w/w) significantly influenced the syneresis level, its apparent viscosity, yield stress and thixotropic behaviour. The overall sensory quality scores indicated that yoghurt enriched with 1.5% triticale insoluble fibres was recognised as 'excellent' and had enhanced antioxidant activity.

CONCLUSIONS

Insoluble triticale fibre could therefore be used as a supplement to produce functional yoghurt. © 2017 Society of Chemical Industry.

Physicochemical and Rheological Properties of a Dairy Dessert, Enriched with Chickpea Flour

Dairy desserts are complex mixtures and matrices including main components such as milk, sugar, starch, hydrocolloids, colorants and flavors, with a proteinaceous structure; they are widely consumed and present a semisolid consistency. In this work, the physicochemical and rheological properties of a dairy dessert with the addition of chickpea flour (raw and cooked, at four concentrations) were studied to determine the effect of the flour. The results indicated that luminosity (L*: 62.75–83.29), pH (6.35–7.11) and acidity (1.56–3.56) changed with the type of flour. The flow properties of the custards exhibited a non-Newtonian behavior that was well fitted by three flow models. The studied custard systems were stored for twelve days at 4 °C. The physicochemical and flow properties of the custards changed notably as a function of flour addition and storage time. From all samples, only four were analyzed with oscillatory tests, showing their mechanical spectra with elastic behavior. The dessert texture was also measured, founding that those formulated with Blanco Noroeste chickpea flour exhibited the highest values of hardness (0.356–0.391 N) through the twelve days. It can be concluded that those custard systems with the highest content of flour presented a very good response as a potential new dairy product.