Stirred Yogurt Research Articles

Functional and Nutritious Characteristics of Nanocurcumin-Enhanced Stirred Yogurt in Alloxan-Induced Diabetic Rats

Functional and Nutritious Characteristics of Nanocurcumin-Enhanced Stirred Yogurt in Alloxan-Induced Diabetic Rats

Influence of Bilberry Pomace Powder Addition on the Physicochemical, Functional, Rheological, and Sensory Properties of Stirred Yogurt.

Fruit processing by-products could represent a sustainable ingredient for developing innovative dairy products. The present study was conducted to develop a novel functional yogurt by adding bilberry pomace powder (BPP) at 0.5%, 1.0%, and 1.5% (w/w) levels in stirred-type yogurt production to confer color and to increase the dietary fiber and polyphenol content. Physicochemical properties of the yogurt samples, including color parameters, titratable acidity, pH, water holding capacity (WHC), and syneresis, as well as textural and rheological properties, were evaluated in yogurts on the 1, 14, and 28 days of refrigerated storage (4 °C). In addition, total phenolic content, total anthocyanin content, and radical scavenging activity were determined in yogurts, and sensory analysis was conducted. The results showed that BPP is a valuable source of polyphenols, dietary fiber, and oils rich in n-3 polyunsaturated fatty acids (n-3 PUFAs, n-6/n-3 ratio = 0.91). The incorporation of BPP imparted an attractive purple color to the yogurts, increased WHC, and reduced syneresis. Moreover, the addition of BPP improved the rheological properties, demonstrating that a more dense and stable yogurt gel network structure was obtained than the control. The yogurt enriched with 1.0% BPP received the highest scores for color, consistency, taste, and overall acceptability. Hence, bilberry pomace powder might be used as an ingredient to improve the nutritional and functional value of yogurts.

Preparation and Properties of Stirred Yogurt Supplemented with Powdered Doum (Hyphaene thebaica) Fruit

Preparation and Properties of Stirred Yogurt Supplemented with Powdered Doum (Hyphaene thebaica) Fruit

Beetroot Stalk Extract as a Functional Colorant for Stirred Yogurt Beverages: Effect on Nutritional Value and Stability during Storage

Betalains are natural red colorants characterized by their stability to anthocyanins, particularly in acidic foods. Beetroot stalks are a good source of betalains, with higher bioactive components than the whole root. Hence, the current study aims to investigate the potential use of beetroot stalk water extract (BSE) as a functional colorant for raspberry-flavored stirred yogurt. For this purpose, the betalains of BSE and their stability at pH 4 and 5 were investigated in addition to the phenolic and flavonoid content. Furthermore, the antioxidant and antimicrobial activities of BSE were characterized. Subsequently, BSE was added to raspberry-flavored stirred yogurt at concentrations of 1 (T1), 2 (T2), and 5% (T3) to study the stability of betalains, the physicochemical properties, the nutritional value, and the viability of lactic acid bacteria during storage (14 days/4 °C). BSE showed a considerable amount of betalains (456.82 mg/L) and phenolics (139.87 mg/g), with a high content of chlorogenic and ferulic acids. The betalains showed greater stability at pH 4 than pH 5 after 14 days of cold storage (275.05 and 247.00 mg/L, respectively). Applying BSE resulted in a functional beverage with high phenolic content (116.55 ± 1.23 mg/g) and flavonoids (71.77 ± 0.57 mg/g) in T3 (5%) compared to the control (95.11 ± 1.12 and 64.72 ± 0.29 mg/g, respectively). The beverages shared high DPPH scavenging activity (IC50 = 71.68 ± 1.30– 69.18 ± 0.48) compared with the control (78.47 ± 3.27 µL/mL). BSE significantly increased the betalain level in yogurt from 44.19 ± 0.05 mg/L to 67.86 ± 0.54 mg/L, resulting in pale red beverages with a redness value of 6.38–9.68 on day 1. By day 14, the redness of the treatments decreased by 6–18% compared with the first day, reaching 5.25 ± 0.03 (T1), 7.87 ± 0.03 (T2), and 8.43 ± 0.05 (T3) due to the degradation of betalains. Generally, BSE is a promising natural colorant when added to stirred yogurt, and it has preferable physical and sensory properties, as it improves the stability of the red color throughout cold storage and increases the nutritional quality. The use of beet stalks as a natural and functional colorant is presented for the first time in the current investigation.

Incorporation of Encapsulated Yoghurt Bacteria into Stirred Yoghurt to Improve their Survival in an In Vitro Digestive Conditions

Incorporation of Encapsulated Yoghurt Bacteria into Stirred Yoghurt to Improve their Survival in an In Vitro Digestive Conditions

Physicochemical, sensory and microbiological characteristics of coriander seed powder yogurt

Yogurt is a fermented food obtained by the bacterial fermentation of milk. In the present work, the effect of different concentrations (1, 3 and 5% w/w) of coriander (Coriandrum sativum) seed powder on physicochemical, sensory characteristics and viability of Bifidobacterium bifidum and Lactobacillus acidophilus of probiotic yogurt were investigated at 4 °C for 21 days. Laboratory-made yogurts were obtained by inoculating milk with yogurt bacteria (mixed culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) and two probiotic cultures (Lactobacillus acidophilus and Bifidobacterium bifidum). According to the results, the viability of B. bifidum and L. acidophilus increased in synbiotic stirred yogurts with 5% CSP (coriander seed powder) up to 9.15 ± 0.09 log CFU/g at 11 days of the storage period, whereas probiotic bacteria count decreased to 9.02 ± 0.01 by the end. Therefore, our results confirmed that the addition of probiotics and CSP powder improved the physicochemical and sensory characteristics of stirred yogurt and exerted a beneficial effect on probiotic bacteria.

Physicochemical and Nutritive Quality Characterization of Developed Banana Stirred Yogurt

Physicochemical and Nutritive Quality Characterization of Developed Banana Stirred Yogurt

Physicochemical and Rheological Characteristics of Stirred Yogurt Fortified with Vitamin B12 and Melatonin

Vitamin B12 and melatonin were added to whole milk-stirred yogurt to evaluate its physicochemical (fat, protein, total solids, moisture, syneresis, and color), rheological (flow behavior and dynamic rheology), and color characteristics as L , a ∗ , and b ∗ and color change ( ∆ E ). For this, five treatments (T) were elaborated as follows: T1 = yogurt (Y) without vitamin B12 and melatonin, T2 = Y with 3 μg/L of B12, T3 = Y with 5 mg/L of melatonin, T4 = Y with 2 μg/L of B12 and 3 mg/L of melatonin, and T5 = Y with 3 μg/L of B12 and 5 mg/L of melatonin. The fortification of yogurt with vitamin B12 and melatonin modified ( P < 0.05 ) the content of fat, moisture, and syneresis. Treatment 5 presented the lowest content of fat and the largest content of moisture ( P < 0.05 ). Treatment 4 had the largest syneresis at day 1, and at day 14, there was not differences in syneresis among treatments ( P > 0.05 ). Regarding color, luminosity ( L ∗ ) did not have significant differences ( P > 0.05 ) among treatments and neither among storage days, except for T5 that presented the lowest value at day 14. Regarding parameter a ∗ , all treatments presented negative values (tendency to green), and T2, T3, and T5 showed significant differences ( P < 0.05 ) trough time. No significant differences ( P > 0.05 ) were observed for the b ∗ values neither among treatments nor among time. The highest value in Δ E , compare to the control, was observed in T5. Regarding flow behavior, T1 showed a significantly different ( P < 0.05 ) higher flow behavior ( n ) than the rest of the treatments. In general, all the samples indicate an increase ( P < 0.05 ) in the flow behavior ( n ) through the storage time. And the consistency index ( K ) showed significant difference ( P < 0.05 ) between T1 and T2 and T3 and T4. In conclusion, the addition of vitamin B12 and melatonin to yogurt generates changes in the physicochemical and rheological properties; likewise, the addition of melatonin in combination with vitamin B12 showed that the viscoelastic characteristics of the fortified yogurts are like the control yogurt. Since these, treatment 5 presented the most similar values of rheology and syneresis compared to the control, so this combination of B12 and melatonin could be employed to develop a new functional yogurt.

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.

Effects of Lactoferrin Supplemented with Fermented Milk on Obesity-Associated Pancreatic Damage in Rats.

Non-alcoholic fatty pancreas disease is a newly emerging disease that represents an important risk factor for the development of pancreatic cancer. Obesity is a risk factor for pancreatic diseases, including pancreatitis and pancreatic cancer. On the other hand, the development of healthy aspects-based food products is a recent trend. Lactoferrin is a component of the body's immune system, which interacts with DNA, RNA, polysaccharides, and heparin, and it has many biological functions and many important immunomodulatory properties. Thus, this study aims to investigate the enhancement effect of supplementation of lactoferrin with stirred yogurt on weight gain, lipid profile, glucose level, and pancreatic enzymes in animals fed a high-fat diet (HFD). Forty-eight female albino rats were divided into 6 groups treated orally for 45 days as follows: negative control (basal diet), positive control (add 1% cholesterol), stirred yogurt (SY), Lactoferrin LF (100 mg/kg bw), supplementation of lactoferrin with stirred yogurt SY-LF at two concentrations LF1 (50 mg/kg bw) and LF2 (100 mg/kg bw). Blood and pancreas samples were collected for different analyses. Animals fed with a HFD showed a significant increase in body weight, total cholesterol, triglyceride, low-density lipoprotein (LDL), glucose level, amylase, and Lipase enzymes (44.72%, 151.33 mg/dL, 142.67 mg/dL, 85.37 mg/dL, 141.33 mg/dL, 39.33 U/mL, 23.43 U/mL). Moreover, it observed a significant decrease in high-density lipoprotein (HDL, 37.33 mg/dL); meanwhile, SY fortified with lactoferrin was useful in losing weight gain and improving lipid profile, pancreas function, and histological change in the pancreas. The supplementation of lactoferrin at 100 mg/Kg bw with LB. Acidophilus as a probiotic was more effective for pancreas functions. This application is a natural protective alternative to manufactured medicines for children and the elderly as a natural product.

Essential oils nanoemulsion for the flavoring of functional stirred yogurt: Manufacturing, physicochemical, microbiological, and sensorial investigation

Stirred yogurt (SY) is preferred by different category of consumers due to its creamy mouthfeel and pourable texture, which make it an attractive dairy drink. In the current study, the authors developed a special SY which is naturally flavored using different essential oils nanoemulsions and functionalized using lactic acid bacteria. The particle size of the nanoemulsions was <30 nm for all utilized essential oils which included spearmint, lemongrass, clove and cinnamon. Three strains of lactic acid bacteria namely, L. helveticus , L. acidophilus and B. bifidum lactis were able to survive in the presence of the different nanoemulsions with bacterial count > 10 6 cfu/ml. Therefore, they were applied as supplements to the flavored SY during manufacture to enhance its functionality. The different rheological and physicochemical evaluations conducted on the developed SY indicates no effect of the EOs nanoemulsion on the general characteristics of SY along a storage period of 15 days. Overall sensory evaluation showed that all fresh EOs-flavored SY got highly preferred scores, however, at the end of storage period only lemongrass-flavored SY kept that score, while the other flavored samples were judged as preferred. The order of preference was lemongrass first followed by cinnamon, mint and clove. The article gives an insight on the application of EO nanoemulsions for developing naturally flavored functional dairy products especially stirred yogurt.

Quality Characteristics of Stirred Yoghurt Added with Myrtus communis L. Fruit Jelly

Quality Characteristics of Stirred Yoghurt Added with Myrtus communis L. Fruit Jelly

Nutritional Importance of Stirred Yogurt

Yogurt is a nutrient-rich food product obtain by bacterial fermentation of milk. Recently, numerous studies have been reported its tremendous health effects through fortification and addition of different fruits provides several nutrients which may help to upgradation of health of vulnerable groups. Fruits yogurt is excellent source of essential amino acids, calcium, vitamin D, riboflavin, vitamin B6 and vitamin B12. It promotes gut microbial population as carrier of probiotics which control intestinal infections reduce the serum cholesterol levels and lactose intolerance and reduce the chance of cancer. Yogurt is a functional food, preventive medicine, and residence treatment in the new times requires persistent and transparent public education. This review paper highlighted the importance of fortification of indigenous fruits to makes fruits yogurt.

Quality parameters of natural phenolics and its impact on physicochemical, microbiological, and sensory quality attributes of probiotic stirred yogurt during the storage.

Physicochemical, microbiological, and organoleptic properties were evaluated for probiotic stirred yogurts with plant pigments; 10% Hibiscus, 4% Turmeric, 6% Spinach, and 4% Blue pea, over 14days at 4℃ compared to the colorless control. The color of yogurts were stable without sedimentation or adverse effect on physicochemical or sensory properties, although an increase of L* value observed over the storage. The microbial analysis confirmed the viability of probiotics (>9 logs CFU/mL) in all yogurts over the storage. Turmeric added yogurt resulted in the highest b* value, total phenolic content (72.6mg GAE/L) and sensory score for color, while spinach added yogurt ranked the lowest in flavor at the end of storage. Results demonstrated the color stability of studied plant pigments in stirred yogurt with varying physicochemical and sensory properties. Addition of natural colorant in yogurt is recommended. Improved methods for extracting pigments and their health effects should be further examined.

Buffalo stirred yoghurt fortified with grape seed extract: New insights into its functional properties

Grape seed extract (GSE) is considered one of the major byproducts, which are rich in phenolic content and possess several health-promoting activities including antibacterial, anticancer, and antioxidant. The current research was devoted to improve the bioactive properties of stirred yoghurt through supplementation with GSE at three concentrations (0.1, 0.25, and 0.5 g/100 g yoghurt). The obtained stirred yoghurts were analyzed for determining their composition, pH, syneresis, viscosity, and sensory evaluation. Furthermore, some functional properties including antioxidant, antibacterial, anticancer activities were estimated. Significant increments (p ≤ 0.05) were observed in total solids, ash contents, pH, water holding capacity, and viscosity values, especially when 0.5% GSE was added. Moreover, adding 0.5% GSE showed higher (p ≤ 0.05) in vitro antioxidant, antibacterial, and anticancer activities. Interestingly, the improved bioactive properties resulting from adding GSE, even at the higher concentration, were not accompanied by any change in sensory properties. In particular, the color descriptor was mostly preferred by panelists when 0.5% GSE was added. The assessors did not observe any off-flavors in any of the tested stirred yoghurt samples. Therefore, the functional properties of stirred yoghurt could be improved by adding GSE preparation without affecting its organoleptic properties.

Effect of a microencapsulated synbiotic product on microbiology, microstructure, textural and rheological properties of stirred yogurt

In this study, synbiotic microcapsules composed of Lactobacillus paracasei (Lacticaseibacillus paracasei) and lactitol were added into milk to prepare probiotic stirred yogurt. The number of lactic acid bacteria, pH, water holding capacity (WHC), texture, rheological properties and microstructure were measured during 4 °C storage to evaluate the characteristics of yogurt. Yogurt containg microcapsules had an increase in the number of lactic acid bacteria and a lower post-acidification when compared to the yogurt containg free cells of L. paracasei during storage. Addition of microcapsules resulted in a product, which observed a higher WHC, cohesiveness and rheological properties. Scanning electron microscope observed that the addition of microcapsules reduced the casein aggregates and pores of the yogurt, leading to a tighter microstructure. In general, the addition of encapsulated L. paracasei could improve the texture performance of yogurt. However, in addition to the increase of probiotics, there was no significant difference between the yogurt with probiotics and synbiotic microcapsules.

Impact of Ultra-High-Pressure Homogenization of Buttermilk for the Production of Yogurt.

Despite its nutritional properties, buttermilk (BM) is still poorly valorized due to its high phospholipid (PL) concentration, impairing its techno-functional performance in dairy products. Therefore, the objective of this study was to investigate the impact of ultra-high-pressure homogenization (UHPH) on the techno-functional properties of BM in set and stirred yogurts. BM and skimmed milk (SM) were pretreated by conventional homogenization (15 MPa), high-pressure homogenization (HPH) (150 MPa), and UHPH (300 MPa) prior to yogurt production. Polyacrylamide gel electrophoresis (PAGE) analysis showed that UHPH promoted the formation of large covalently linked aggregates in BM. A more particulate gel microstructure was observed for set SM, while BM gels were finer and more homogeneous. These differences affected the water holding capacity (WHC), which was higher for BM, while a decrease in WHC was observed for SM yogurts with an increase in homogenization pressure. In stirred yogurts, the apparent viscosity was significantly higher for SM, and the pretreatment of BM with UHPH further reduced its viscosity. Overall, our results showed that UHPH could be used for modulating BM and SM yogurt texture properties. The use of UHPH on BM has great potential for lower-viscosity dairy applications (e.g., ready-to-drink yogurts) to deliver its health-promoting properties.

Stability, bioavailability and antifungal activity of reuterin during manufacturing and storage of stirred yoghurt

High purity reuterin was produced by bioconversion of glycerol using Lactobacillus reuteri and was tested for its bioavailability and antifungal activity in milk and stirred yoghurt. Natamycin was used as a control. In whole milk (3.25% fat) reuterin showed significant inhibition of Rhodotorula mucilaginosa, Aspergillus niger, Penicillium chrysogenum and Mucor racemosus by agar diffusion assay. Minimal inhibitory concentrations ranging from 1.89 mm to 7.58 mm for reuterin and from 0.005 mm to 0.16 mm for natamycin were obtained using the microtitration assay. The inhibitory activity of reuterin was shown to be fungicidal; that of natamycin was fungistatic. In stirred yoghurt kept at 4 °C, addition of reuterin at 10 mm allowed total inhibition of M. racemosus and R. mucilaginosa within 1 week and reduced A. niger counts by 3 log cycles over 4 weeks. The addition of reuterin increased the final pH of the stirred yoghurt and decreased the acidity.

Effects of Fortification Stirred Yoghurt with Red Beet Powder (RBP) on Hypercholesterolemia Rats

The effects of stirred yoghurt fortified with red beet powder (RBP) on hypercholesterolemia rats were investigated during this study. Flavored yoghurts were evaluated for fibers and total phenolic compounds, identification of phenolic compounds of reed beet (RBP) powder. The chemical composition, physicochemical and rheological properties, color measurements and sensory evaluation of resultant yoghurt were evaluated. Thirty male rats were separated into 5 groups, group one negative control, as the other groups were organized hypercholesterolemia groups for two weeks after that, divided to 4 subgroups chase the 1st subgroup present while, positive control, the 2nd subgroup was fed on stirred yoghurt ,the 3rd and the 4th subgroups were given stirred yoghurt containing red beet powder at levels (1% and 2%) respectively. The results revealed that beet root powder had 7.5% fiber and high amount of total phenolic 12.18 mg/g. The level of phenolic compound in RBP there was a large difference with the identified components. The TS content of stirred yoghurt fortified with red beet powder (RBP) was increased by increasing the percentage added and increase the protein content. While the fat content decreasing. Generally, the higher per cent resulted in increasing viscosity value of yoghurt. Stirred yoghurt containing RBP had significant deferent of colour measurements and improved yoghurt properties for overall acceptability. Also, stirred yoghurt containing of RBP had significant different decreasing in organ weights (heart, liver and kidney) of the experimental rats. This study in all rats’ groups fed on stirred yoghurt containing of RBP decreasing of blood lipid profile (T.G, T.C and LDL-c values) and significantly increased the HDL cholesterol. On the other hand, results illustrated of positive group significant increase in liver enzymes (ALT, AST) and (uric acid and creatinine) kidney functions compared with yoghurt containing of RBP which decreased. The histopathological examination of heart, liver and kidney demonstrated more or less normalized in the rat’s groups fed on stirred yoghurt containing RBP compared to the positive group. Thus, the study descriptions that stirred yoghurt containing RBP have rich phenolic compounds and protect against hypercholesterolemia diseases.

Production of Probiotic Stirred Yoghurt from Camel Milk and Oat Milk

The effect of partial replacement of camel's milk with Oat milk on the physicochemical, rheological, microbiological, antioxidant and sensory properties of probiotic stirred camel milk yoghurt during storage was investigated. Stirred yoghurt was made from camel milk served as a control, and the other treatments were made from camel milk after replacing 10, 20, 30 and 40% of it by Oat milk. Resultant stirred yoghurt of other treatments were analyzed after1, 5 and 10 day of storage at 4 ± 1˚C for physicochemical, microbiological, antioxidant and sensory properties Results revealed that partial replacement of camel's milk with Oat milk were more effective in increasing the total solids, protein, ash, total carbohydrates, acidity and total volatile fatty acid (TVFA), viscosity, phenolic content and antioxidant activity and these increments were proportional to the replacement ratio. Partial replacement of camel's milk with Oat milk enhanced the via­bility of Streptococcus thermophiles, Lactobacillus acidophilus and Bifidobacterium bifidum and this enhancement was proportional to the replacement ratio . Probiotic camel milk stirred yoghurt containing 40 % Oat milk had the highest scores for sensory properties compared to other probiotic camel milk stirred yoghurt treatments .Thus, The study concluded that camel milk could be replaced with Oat milk until 40 % as a source of bioactive components and dietary fiber in manufacture of probiotic camel stirred milk yoghurt, this replacement up to 40% improved the physicochemical, rheological, microbiological antioxidant and sensory properties of resultant yoghurt.