Rheological Properties Of Yogurt Research Articles

The Impact of Cassia fistula Polysaccharide on Flavor Compounds Formation and the Rheological Properties of Yogurt during Storage

The Impact of Cassia fistula Polysaccharide on Flavor Compounds Formation and the Rheological Properties of Yogurt during Storage

Effect of guar gum and fortification by haritaki (Terminalia chebula) extract and its encapsulates on physicochemical, textural, and rheological properties of yogurt

AbstractIn the present study functional yogurt was prepared by addition of guar gum (0.5% and 1.5%) and fortification by phytochemical extract of haritaki (Terminalia chebula) extracted using supercritical CO2 and freeze dried encapsulates of the extracts. The results indicated that the addition of guar gum led to a concentration‐dependent reduction in pH, with yogurt containing 1.5% guar gum exhibiting the highest acidity. During a 24‐day storage period at 4°C, all samples displayed a decrease in pH and an increase in acidity. Notably, all variations exhibited sporadic syneresis patterns, with higher syneresis observed on the 1st day, followed by a decline on the 12th day and a subsequent rise on the 24th day of storage. The color of haritaki encapsulated yogurt appeared greener and more yellowish compared to the control samples on the 1st day, with noticeable changes in L*, a*, and b* values during storage. Texture analysis revealed that encapsulation significantly affected textural characteristics, with reduced firmness but comparable adhesiveness in some cases. The firmness of plain yogurt ranged from 0.69 to 0.72 N, while its adhesiveness was between 6.14 × 10−2 and 8.51 × 10−2 N.s. The stiffness of the samples made with encapsulates (E1–E6) ranged from 0.38 to 0.70 N, while their adhesiveness was 5.74 × 10−2 to 8.78 × 10−2 N.s. The findings demonstrate that encapsulation significantly affected the textural characteristics. However, the samples' firmness (F1–F3) was less than the control, ranging from 0.36 to 0.54 N. Encapsulated haritaki extract outperformed nonencapsulated haritaki extract in terms of phenolic and antioxidant activities, making it a preferred option for yogurt fortification. Furthermore, yogurt enriched with up to 0.5% guar gum exhibited sensory qualities similar to or even better than the control sample.

Application of natural and modified additives in yogurt formulation: types, production, and rheological and nutraceutical benefits.

Yogurt, a popular fermented dairy product, is of different types and known for its nutritional and nutraceutical benefits. However, incorporating additives into yogurt has been adopted to improve its functionality and nutraceutical properties. Additives incorporated in yogurt may be natural or modified. The incorporation of diverse natural additives in yogurt formulation, such as moringa, date palm, grape seeds and argel leaf extracts, cornelian cherry paste, mulberry fruit and leaf powder, lentil flour, different types of fibers, lemongrass and spearmint essential oils, and honey, has been reported. Similarly, modified additives, such as β-glucan, pectin, inulin, sodium alginate, and gelatin, are also added to enhance the physicochemical, textural, sensory, and rheological properties of yogurt. Although additives are traditionally added for their technological impact on the yogurt, studies have shown that they influence the nutritional and nutraceutical properties of yogurt, when added. Hence, yogurts enriched with functional additives, especially natural additives, have been reported to possess an improved nutritional quality and impart several health benefits to consumers. These benefits include reducing the risk of cardiovascular disease, cancer, osteoporosis, oxidative stress, and hyperglycemia. This current review highlights the common types of yogurt, the production process, and the rheological and nutraceutical benefits of incorporating natural and modified additives into yogurt.

Effects of different strains fermentation on the sensory and nutritional properties of soy-based yogurt.

Soy protein is the only full plant protein that is comparable to animal protein. Soy whey contains a variety of nutrients including isoflavones and oligosaccharides. Additionally, different strains have profound influence on functional metabolism. Most prospective studies used mixed strain fermented yogurt, but few studies on single strain fermented yogurt. The present study aimed to ferment nutritious and healthy soy-based yogurt using a single strain and to provide technical support for the reuse of soy whey. Streptococcus salivarius subsp. thermophilus HCS07-002, Bifidobacterium animalis subsp. lactis HCS04-001 and Lactiplantibacillus plantarum HCS03-084 had strong growth and metabolic activities. Bifidobacterium animalis subsp. lactis HCS04-001 fermentation raised the texture and rheological properties of yogurt and enriched the flavor substances in the yogurt, resulting in a good quality soy-based yogurt. The contents of arginine, glutamic and proline were greatly affected by the fermentation of different strains. The fermentation of B. animalis subsp. lactis HCS04-001 was beneficial to the enrichment of soy isoflavone and equol in yogurt, and enhanced antioxidant activity of yogurt. Our findings indicated that yogurt fermented with B. animalis subsp. lactis HCS04-001 had the best sensory and nutritional properties, which provides valuable insights into the selection of suitable strains to improve the quality and nutritional value of plant yogurt. © 2023 Society of Chemical Industry.

Yogurt Enriched with Mango Peel Extracts (Mangifera indica) in Chitosan–Xanthan Gum Dispersions: Physicochemical, Rheological, Stability, and Antioxidant Activity

Different strategies have been developed to incorporate bioactive compounds into food products to improve their biological activity against degradation effects. The aim of this study was to develop natural yogurt enriched with mango (Mangifera indica) peel extracts (MPEs) in chitosan–xanthan gum dispersions and to evaluate their physicochemical, rheological, and antioxidant activity. A hydroethanolic extract of mango peel was obtained, with a yield of 33.24 ± 1.27%, a total content of phenolic compounds of 305.04 ± 10.70 mg GAE/g, and an antioxidant activity of 1470.41 ± 59.75 μMol Trolox/g. The encapsulation of the extracts was achieved using a chitosan–xanthan gum dispersion, resulting in the rheological characteristic of a strong gel. The incorporation of dispersions into yogurt did not modify the physicochemical properties and increased their bioactive properties. The rheological properties show samples with double yield points and a decrease in viscoelastic parameters. These results show dispersions as a strategy to incorporate bioactive compounds into dairy products, preserve the physicochemical and rheological properties of yogurt, and improve their biological activities (such as antioxidant activity) and activities related to the compounds found in the MPE.

Effects of carao (Cassia grandis L.) on physico-chemical, microbiological and rheological characteristics of yogurt

Yogurt fortification with functional ingredients can increase health benefits. Carao fruit has bioactive compounds which could exert antidiabetic potential. Objective was to study the influence of carao powder on physicochemical, microbiological, and rheological properties of yogurt. Carao powder was added at 0, 1.3, 2.65, and 5.3 g/L to milk to produce yogurt, which was stored for 42 days. The pH, titratable acidity (TA), syneresis, color, Streptococcus thermophilus (ST) and Lactobacillus delbrueckii spp. bulgaricus (LB) counts, viscosity, steady shear flow, thixotropic analysis, and frequency sweep measurements were evaluated over yogurt shelf life. The protease activity of yogurt starter culture bacteria and particle size of the carao were also measured. Particle size distribution of carao powder varied. Carao did not affect the syneresis and the growth of ST and LB. Carao yogurt decreased pH and L* values and increased a*, b*, n’, TA, and viscosity values. At 42 days, thixotropic behavior increased with the addition of carao. Carao also increased the protease activity of yogurt starter culture bacteria in skim milk. Carao could be added to yogurt without producing major changes to its characteristics.

Physicochemical properties, antigenicity and allergenicity of yoghurt fermented by Lactiplantibacillus plantarum AHQ‐14 combined with starter

SummaryCow milk proteins is one of the major food allergens, and some probiotics can abate allergenicity to some extent. Lactiplantibacillus plantarum AHQ‐14 isolated from the traditional dairy products in Xinjiang Province, China, has good ability to reduce the allergenicity of β‐lactoglobulin (LG) and good probiotic properties. In the presented study, L. plantarum AHQ‐14 was used to replace half of the commercial yoghurt starter to ferment yoghurt, and the effects of L. plantarum AHQ‐14 fortification on microstructure, textural and rheological attributes of yoghurt were investigated. In addition, milk protein hydrolysis, antigenicity and allergenicity of yoghurts during 28 days of cold storage were detected. The results indicated that AHQ‐14 and YC‐X11 fermentation could enhance the texture and rheological properties of yoghurt by reducing the syneresis (37%) and firmness (14%) and improving the cohesiveness by 50%. In addition, AHQ‐14 and YC‐X11 fermentation can shorten the fermentation time by about 30 min, SDS‐PAGE displayed that AHQ‐14 and YC‐X11 fermentation had stronger hydrolysis of whey protein compared with YC‐X11 yoghurt. Additionally, the fermentation by L. plantarum AHQ‐14 and YC‐X11 could significantly reduce the antigenicity and IgE‐binding ability of skim milk by 82% and 94%, respectively, thus reducing milk‐allergic reactions in patients significantly.

Incorporation of Solid Lipid Nanoparticles into Stirred Yogurt: Effects in Physicochemical and Rheological Properties during Shelf-Life

The aim of this work was to develop a yogurt fortified with curcumin. Curcumin is a lipophilic compound with a wide range of biological activities; however, it presents low water solubility and low bioavailability, and therefore it was the first to be encapsulated in solid lipid nanoparticles (SLNs). Then the influence of the incorporation of curcumin-loaded SLNs on the physicochemical (i.e., pH, titratable acidity, syneresis and color) and rheological properties of yogurt during its shelf-life (30 days at 4 °C) was evaluated. SLN incorporation into yogurt did not affect pH and titratable acidity compared to the control (i.e., plain yogurt) during shelf-life, even though the yogurt with SLNs presented lower values of pH (4.25 and 4.34) and acidity (0.74% lactic acid and 0.84% lactic acid) than the control in the end, respectively. Furthermore, the yogurt with SLNs presented slightly higher values of syneresis than the control during the shelf-life; however, it did not present visual differences in whey separation. Relative to the color, the incorporation of SLNs into the yogurt imparted a strong yellow color to the sample but did not affect color stability during shelf-life. Both samples showed flow curves with yield stress and shear-thinning behavior during shelf-life, and, regarding the viscoelastic behavior, both showed a typical weak viscoelastic gel with an elastic structure. Overall, curcumin-loaded SLNs incorporation did not affect the physicochemical and rheological stability of yogurt during shelf-life, showing a promising application for the development of new functional foods.

Improving the sensory and rheological properties of yogurt using aqueous extract of basil (Ocimum basilicum L.)

This study aims to produce a therapeutic milk product (yogurt) to improve and treat many different digestive problems, using the lactic acid bacteria (Streptococcus thermophilus and Lactobacillus bulgaricus) supplemented with aqueous extract of the plant (basil) with three concentrations of 1%, 3% and 5% [v/v] basil, they were represented by R1, R2 and R3 treatments respectively, as well as the control [C] treatment in which the yogurt was made without any addition. The treatments were stored for 21 days at [5±1] °C. The physicochemical properties were studied, which included measurement [pH, total acidity, syneresis, viscosity, and hardness] and microbiological examinations, as well as sensory evaluation on the first day of manufacture and after 7, 14 and 21 days of cold storage. The results showed that there were no significant differences in pH values immediately after manufacturing for all treatments. As for the percentage of total acidity (TTA), it was close to immediately after manufacturing for all the different yogurt treatments, while during storage, a clear increase in their values was observed for all transactions. Results showed a significant difference in syneresis, viscosity and hardness immediately after manufacturing and during cold storage for all treatments. R1 and R2 treatments improved the viscosity, hardness and syneresis of yogurt. The R2 and R3 treatments recorded the highest numbers of starter bacteria compared to the other treatments. Also, the results showed that the superiority of R2 treatment in the sensory evaluation of the characteristics of taste, flavor, texture and general acceptance.

Effect of whey and soy proteins fortification on the textural and rheological properties of value-added yogurts

The objective of this study was to develop whey and soy proteins fortified value-added yogurts based on their textural and rheological properties to meet a high demand to increase protein content of conventional yogurts for many health benefits. Seven yogurts (control, 1, 3 and 5% of whey/soy proteins) were developed by fortifying with whey and soy proteins. The protein fortified yogurts were compared with control (without protein fortification) for their textural and rheological properties. The dynamic viscosity of yogurts was determined, and the shear stress-shear rate relationship was modeled using a power law equation to determine the apparent viscosity and flow behavior of yogurts. There was a significant effect of protein fortification on the textural and rheological properties of yogurts (p < 0.05). The textural properties and viscosities of 1-5% soy protein fortified samples were close or better to control. Textural and rheological properties of the yogurts indicated that up to 5% soy protein could be incorporated for the quality yogurts. whereas only 1-3% whey fortification of yogurt was possible because 5% whey protein created aggregates and syneresis of yogurts. Power law modeling could predict the shear stress and shear rate relationship and apparent viscosity of all yogurts with an accuracy of 80-99% depending on level of protein fortification and protein type. Dynamic viscosity and apparent viscosity of all yogurts decreased with shear rate. Power law (n < 1) showed that all yogurt samples were shear thinning products. The desired viscosity could be obtained using an optimum protein fortification. The study indicated that soy protein could be used as an alternative to whey protein for the improved protein fortified yogurt production.

Processing properties of yogurt as affected by the EPS produced by Leuconostoc mesenteroides XR1

SummaryThe aim of this study was to examine the fermentation characteristics of a novel Leuconostoc mesenteroides strain (XR1) and to investigate the effect of XR1 exopolysaccharides (EPS) on the microstructure, texture and rheological properties of yoghurt. The novel Leuconostoc mesenteroides strain (XR1) was isolated from wild kefir grains obtained from Xinjiang Province. The results showed that XR1 had good EPS production capacity and favourable fermentation performance. The addition of XR1 EPS to fermented milk effectively improved the water‐holding capacity (WHC) of the fermented milk and changed its microstructure. In subsequent fermentation studies, the XR1 strain was found to be a compatible strain, and the steric barrier formed between XR1 EPS and the fermented milk proteins enhanced its viscoelastic properties. Rheology studies indicated that fermented milk supplemented with EPS possessed a higher modulus (G’, G’’ ) and complex viscosity. Thus, these results indicate that XR1 EPS are useful as a natural organic additive that can replace chemical additives in dairy products.

Effect of Flaxseed Powder on Physicochemical, Rheological, Microbiological and Sensory Properties of Yoghurt

HIGHLIGHTS Effects of the addition of flaxseed powder (FSP) were examined on yoghurts. The FSP improved syneresis and water holding capacity of yoghurts. The FSP enhanced viscosity and rheological properties of yoghurts. Microbiological properties of FSP added yoghurts was coherent with legal. The sensory properties of FSP added yogurts were acceptable except for one containing 1%.

Effect of process variables on the physicochemical and rheological properties of yogurt

In this research, the effect of the lactic starter culture, the fermentation time, the incubation temperature and the percentage of fat on the firmness and consistency of a fermented milk drink was evaluated through physicochemical characteristics of total acidity, pH, syneresis and flow behavior. The purpose was to find the best formulation that extends the shelf life of yogurt, leading to an improvement in the manufacturing process of a local dairy company in Barrancabermeja (Santander, Colombia). Quality criteria were evaluated by means of the percentage of acidity and pH of the yogurt, as well as its syneresis and rheological parameters during a storage time of 24 hours and 7 days in refrigeration. Acceptable quality parameters were obtained for the yogurt prepared with an inoculum concentration of 2%, an incubation temperature of 40°C and an incubation time of 150 minutes. In addition, better properties of firmness and consistency were found, with absence of syneresis and viscosity in the accepted range, for this dairy product.

Effects of Esterified Rice Flour with Citric Acid on Physicochemical and Rheological Properties of Yogurt

Effects of Esterified Rice Flour with Citric Acid on Physicochemical and Rheological Properties of Yogurt

Effect of Two Combined Functional Additives on Yoghurt Properties.

The aim of the research was the analysis of yoghurts enriched with blue honeysuckle berries dry polyphenolic extract and new preparation of resistant starch. The additives were introduced individually at concentration 0.1% (w/v) and in mixture at final concentration of 0.1 and 0.2% of both components. Yogurt microflora, pH, and its physicochemical and antioxidant properties were examined over 14 days of storage under refrigerated conditions. Studies showed that both substances can be successfully used in yoghurt production. Yoghurt microflora es. S. thermophilus and Lb. delbrueckii subsp. bulgaricus counts appeared to be higher in samples supplemented with these additives comparing to control yoghurt by 3–8%. More stimulating effect on their growth, especially on S. thermophilus, revealed resistant starch. Addition of this polysaccharide improved also the rheological properties of yogurts, which showed higher viscosity than samples produced without it. Addition of honeysuckle berries preparation significantly influenced the yogurts’ color, giving them deep purple color, and their antioxidant potential. During storage, contents of anthocyanin and iridoid compounds were decreasing, but antioxidant activity in the products remained stable.

Impact of sturgeon gelatin hydrolysates (SGH) on physicochemical and microbiological properties of fat-free set-type yogurt

Gelatin was extracted from beluga sturgeon (Huso huso, SG) and the effects of sturgeon gelatin hydrolysates (SGH) on physicochemical, textural, and rheological properties of yogurt during 28 days of refrigerated storage were explored in this study. SGH at 2 g/dL in yogurt showed the best survival of Lactobacillus bulgaricus, Streptococcus thermophilus, and Bifidobacterium lactis. Based on the results, SGH at 1 g/dL significantly decreased the flow behavior index (n) while increasing the values of k (consistency coefficient), complex viscosity (η*), and yield stress (τ0). Dynamic shear rheological properties indicated higher storage modulus (G′), loss modulus (G″), and η* values at all frequency values compared to control (Yc) whereas Ysgh1 g/dL (yogurt with added SG and SGH) had a better solid-like behavior and elastic gel structure. Ysgh had a higher acidification rate during fermentation and water-holding capacity compared to Yc. However, syneresis and hardness increased and decreased at 2 g/dL SGH, respectively. Overall, SGH might be useful as the potential natural ingredients of fat-free set-type yogurt.

Optimization of High Hydrostatic Pressure Treatments on Soybean Protein Isolate to Improve Its Functionality and Evaluation of Its Application in Yogurt.

This work aimed to improve the functional properties of soybean protein isolate (SPI) by high hydrostatic pressure (HHP) and develop SPI incorporated yogurt. Response surface methodology (RSM) was used to optimize the HHP treatment parameters, including pressure, holding time, and the ratio of SPI/water. Water holding capacity, emulsifying activity index, solubility, and hardness of SPI gels were evaluated as response variables. The optimized HPP treatment conditions were 281 MPa of pressure, 18.92 min of holding time, and 1:8.33 of SPI/water ratio. Water and oil holding capacity, emulsifying activity, and stability of SPI at different pH were improved. Additionally, relative lipoxygenase (LOX) activity of HHP treated SPI (HHP-SPI) was decreased 67.55 ± 5.73%, but sulphydryl group content of HHP-SPI was increased 12.77%, respectively. When incorporating 8% of SPI and HHP-SPI into yogurt, the water holding capacity and rheological properties of yogurt were improved in comparison with yogurt made of milk powders. Moreover, HHP-SPI incorporated yogurt appeared better color and flavor.

Utjecaj dvaju suplemenata u hranidbi koza na tehnološka svojstva kozjeg mlijeka

Goat’s daily diet is usually based on grazing, hay and/or feed supplements. Feed supplements are crucial in the diet of high productive goats to achieve their genetic potential and breeders must choose balanced feeding regime to produce large quantities of milk without affecting the technological quality of milk. In the present study, we evaluated the influence of two commercially available feed supplements on goat milk coagulation properties and rheological properties of yoghurts. Goats of the Slovenian Alpine breed (61) were fed with two feed supplements during the 3-year experiment. Feed supplement 1 (FS1) had higher proportions of barley and alfalfa, while feed supplement 2 (FS2) had added premix of minerals and vitamins and had higher proportions of wheat and sunflower meal. Con¬sequently, FS1 had more crude fibres, which is the most probable reason for approximately 15 % higher firmness, consistency and cohesiveness (P&amp;lt;0.05) of yoghurts in FS1 group, compared to the FS2 group. Moreover, the rennet coagulation time (r) was shorter (P&amp;lt;0.05) in the FS1 group, compared to the FS2 group. Curd firmness 30 min after enzyme addition (a30) was also higher in FS1 group although the results were not statistically significant. Taking together, our results indicate that goats fed with FS1 produced milk with better technological properties compared to those fed with FS2, despite the fact that there were no significant differences in chemical composition of milk from each group. We showed that careful selection of feed supplement’s constituents could improve technological properties of goat milk. However, further studies are needed to evaluate the mechanisms of the observed differences.

Effect of the selected whey protein preparations on exopolysaccharides production by lactic acid bateria and rheological properties of yoghurt

Effect of the selected whey protein preparations on exopolysaccharides production by lactic acid bateria and rheological properties of yoghurt

Effect of the Yam Starch (&lt;em&gt;Dioscorea&lt;/em&gt; spp.) and Pectin on the Rheological Properties of Stirred Yogurt

The aim of study was to evaluate the effect of the temperature and concentration of yam starch and pectin on the rheological properties of yogurt. A stationary test was performed using an MCR 302 (Anton Paar) rheometer with concentric cylinder geometry, varying the strain gradient in an ascending (0-100/sec) and a descending (0-100/sec), at different temperatures (10, 20 and 30°C, respectively). Yogurts were made using two varieties of yam starch (“Espino” and “Criollo”) and different concentrations of yam starches (0.1, 0.3 and 0.5% w/w, respectively) and pectin at 0.3% w/w was used as a commercial reference. The experimental data were fitted to the power law models, Herschel-Bulkley and Casson. The model that best represented the rheological data was the power law $(R^2≥0.977, MSE≤0.674)$. Yogurts with an addition of yam starch presented thixotropy and pseudoplastic behavior $(0 < n < 1 )$; However, when pectin was used at 30°C the behavior was dilating (n = 1.23). Yogurts with “Criollo” yam starch have higher consistency, while yogurt with an addition of “Espino” yam starch are more pseudoplastic and have less thixotropy.