Set-type Yoghurt Research Articles

Effect of Ganoderma lucidum water extract on flavor volatiles and quality characteristics of set-type yogurt

This study investigated the effects of several concentrations of Ganoderma lucidum water extract (GLWE) (0, 0.5, 1.0, and 1.5 %) on set-type yogurt's flavor volatiles as well as the physicochemical, textural, and antioxidant activities of the yogurt during storage. The HS-SPME-GC–MS investigation found that adding GLWE increased the amount of flavor volatiles in yogurt, which improved the quality of flavor volatiles produced by the yogurt. The yogurt's water holding capacity, syneresis, color, and texture all showed optimum values at a 0.5 % GLWE concentration, and its total number of flavor volatiles reached 43. To sum up, the incorporation of GLWE at a 0.5 % concentration promotes the development of superior flavor volatiles in yogurt and enhances its qualitative attributes in contrast to the control group.

Probiotic set yogurt infused with orange pulp: A multifaceted evaluation of nutritional, antioxidant, and physical attributes.

Fortification of yogurt with orange pulp tends to increase its protein network strength resulting in reduced syneresis. The aim of the current study was to prepare set-type orange yogurt with cow milk, skim milk powder, guar gum, and orange pulp at 0%, 1.0%, 2.0%, 3.0%, and 4.0% concentrations, respectively. The changes in proximate, total soluble solid, antioxidant activity, ascorbic acid, and syneresis were assessed. Yogurt was stored for consecutive three weeks during that duration all attributes were evaluated weekly. Set-type orange pulp incorporated yogurt significantly increased the fat (3.91% to 4.9%), protein (3.90% to 3.94%), moisture (84% to 84.80%), total soluble solids (16.01% to 18.51%), ascorbic acid (16.99% to 20.43%), and syneresis (28.90% to 29.94%), respectively. Overall results indicate that 4% orange pulp-enriched set-type yogurt presented more stable parameters as compared to other formulas.

Aqua Extracts of Lyophilized Sea Buckthorn Modify Fermentation and Quality Properties of Set-Type Yogurt

Aqua Extracts of Lyophilized Sea Buckthorn Modify Fermentation and Quality Properties of Set-Type Yogurt

Effects of Dioscorea opposita mucilage addition on the physicochemical properties, texture, and stability of set-type yogurt

Dioscorea opposita mucilage (DOM), a polysaccharide-protein polymer with antioxidant activity, can be served as a natural ingredient in nutritional yogurts. The effects of DOM addition at different concentrations (2%, 4%, 6%, 8%, 10% and 12% w/w) on the total number of lactic acid bacteria, pH, titratable acidity, syneresis, viscosity, texture, color and sensory evaluations of full-fat yogurts and skimmed yogurts during 21 days storage at 4 °C were investigated. The results suggested that DOM could improve the growth of LAB, strengthen the network and gelation of yogurt, and thicken the dispersion, which led to the significant decrease in pH and cohesiveness, and drastic increase in the syneresis, firmness and adhesiveness. Additionally, sensory evaluation revealed that the overall liking scores of full-fat yogurts (8.1–8.7) were higher than those of skimmed yogurts (7.9–8.3), which exhibited strong correlations with firmness and viscosity of set-type yogurts. Although DOM addition affected the sensory undesirably, such as creaminess, the thickness and overall liking were improved, especially for the skimmed yogurts. In summary, 8% w/w DOM could effectively improve the texture, quality and stability of set-type yogurts. This study provides new applications in functional dairy products and promotes the value of the by-products of D. opposita.

Production and Evaluation of Set-Type Yoghurt Fortified with Chlorella vulgaris and Moringa oleifera Powder.

Considering the growing popularity of functional foods, fortifying yoghurt with natural ingredients with various flavours and appearances could improve its nutritional and health potential. The current study aimed to evaluate the effect of Chlorella vulgaris (0.3 and 0.5%) and Moringa oleifera (0.3 and 0.5%) on the fermentation kinetics, apparent viscosity, antioxidant activity, microbiological, sensorial, and FTIR properties of yoghurt during storage. The results demonstrated that the incorporation of Chlorella vulgaris and Moringa oleifera into yoghurt increased acidification rate and decreased fermentation time (p < 0.05). Moringa oleifera (0.5%) improved the growth and survival of lactic acid bacteria as well as the phenolic and antioxidant properties of yoghurt. However, Chlorella vulgaris, at a concentration of 0.5% reduced the viability of lactic acid bacteria, viscosity, total phenolic, and antioxidant properties of yoghurt. In conclusion, it was found that Chlorella vulgaris, at 0.3%, and Moringa oleifera improved the phenolic, antioxidant properties, and acidification rate of yoghurt.

Effects of chrysanthemum extract on physicochemical, sensory, and in vitro digestion of set-type yogurt.

The online version contains supplementary material available at 10.1007/s13197-024-06000-5.

Physicochemical, colour, microbiology, sensory and mineral attributes of set-type yoghurt produced from Gundelia tournefortii L. and its gum

The present study aimed to investigate the production of yoghurt in which the parts of the Gundelia tournefortii L. and its gum were added to milk at levels of 3% (v/v), incubated until the pH value reached 4.7 at 42 °C and then stored at 4 °C for 21 days. The Ca, P, K, Na and Mg contents of the yoghurt sample containing Gundelia tournefortii L. proved to be higher than those found in the control sample. Acidity, acetaldehyde, viscosity, a* values of yoghurt samples increased during storage, while the volatile fatty acids, gel firmness, whey separation, water holding capacity, L* and the b* values were decreased. The lactic acid bacteria count on the 21st day was > 6 log CFU/g in all yoghurt samples. The total aerobic mesophilic bacteria decreased except for the yoghurt sample containing Gundelia tournefortii L. milk, while the yeast and mold increased. The preference map revealed that 60–80% of consumers were satisfied with the control sample and the Gundelia tournefortii L. gum sample. Gundelia tournefortii L. milk and Gundelia tournefortii L. leaves samples were also found to have acceptable scores. As a result, adding Gundelia tournefortii L. into the yoghurt turned out to have a positive impact on its sensory and functional properties and could lead to an innovative approach in the dairy product market.Graphical abstract

Optimization of the stabilizers and cow milk levels for the production of camel milk-based yogurt using response surface methodology

The production of yoghurt from camel milk (CML) is limited due to weak gel formation. As a trial to produce CML-set-type yoghurt, sixteen treatments were prepared from CML, cow milk, and stabilizers (gelatin and gum-Arabic; 1:1) using a D-optimal design. A desirable hardness of set-type yoghurt was obtained from CML (56%), cow milk (42%), and stabilizers (2%). Another study was designed to choose the best combination of stabilizers (1, 1.5 or 2% of gelatin in combination with 1% of gum-Arabic). The increased levels of gelatin resulted in a significant increase (p &lt; 0.05) in the viscosity and consistency index of yoghurt milk, an increase (p &lt; 0.05) in yoghurt hardness and viscosity, and a reduction in syneresis (p &lt; 0.05). In conclusion, an acceptable set-type yoghurt can be produced by using a combination of CML and cow milk (1.3:1) and a stabilizers' mixture of gelatin (1 or 1.5%) and gum-Arabic (1%).

A novel set-type yogurt with improved rheological and sensory properties by the sole addition of insoluble soybean fiber

With the rise of sustainable concepts, the beneficial role of soluble dietary fiber in the preparation of clean labelled yogurt has been recognized, but the role of insoluble dietary fiber remains controversial. In this work, the effect of insoluble soybean fiber (ISF) on the rheological and sensory properties of yogurt was investigated based on the improved structural and physicochemical properties of ISF. The results showed that ISF improved the rheological properties of yogurt in a positive concentration-dependent manner. The viscoelasticity was enhanced, with ISF contributing more to the elastic component than to the viscous component. The viscoelastic structure of yogurt was found to be less sensitive to temperature and stress variations and exhibited thermal reversibility. These observations were attributed to the skeletal support of the ISF on the 3D network structure, the facilitation of interactions within the yogurt gel matrix by the ISF and the gel-like network structure of the ISF itself. Creep recovery and thixotropic properties were also improved after the addition of ISF. By analyzing the metrics of rheological properties using principal component analysis, it was found that yogurts with moderate concentrations (0.25%–0.75%, w/v) of ISF were similar to some non-clean-labelled commercial yogurts. Of these, the yogurt containing 0.5% ISF exhibited the best sensory properties. This study provides insight into the development of insoluble dietary fiber and the manufacture of high-quality clean-labelled yoghurt.

WITHDRAWN: Set-type yogurt with Cucumis melo L. (Kultik) seeds

In this study, possible use of Kultik seed as an alternative food ingredient in production of set yogurt was evaluated. Set-type yogurts were produced from different mixture ratios of cow's milk and kultik seed water extract, and only from kultik seed water extract using transglutaminase. In addition, effect of storage time on yogurt properties were investigated. The properties were total solids, ash and fat content, acidity as pH, titratable acidity as % of lactic acid, syneresis, viscosity features, total phenolic content, antioxidant activity and sensory evaluation.Overall, it was not possible to produce a set-type yogurt only using the seed water extract, however, a vegetarian yogurt was possible to be produced from mixture of the seed water extract and cow's milk. The evaluated properties changed in a ratio-dependent manner. Storage time led syneresis and titratable acidity to increase, and total solid content to decrease due to ongoing fermentation throughout storage period in yogurt samples, p<0.05. Even though the seed water extract addition in yogurt production not only resulted to the decrease in some properties, but also the increase in total solids, fat content and syneresis. Sensory evaluation of costumers in acceptance proved that there is a huge potential to produce a functional food like a set-type yogurt using the seed water extract due to better taste quality and overall acceptance scores of the yogurt produced from 20% the seed water extract+ 80% cow's milk rather than any of other samples including the control at the storage time of 1 day and 15 days. Therefore, the seed water extract has an enormous potential as an alternative vegetarian source for production of fermented dairy products for who have disability of lactose tolerance.

Divergence in physicochemical and microstructural properties of set-type yogurt derived from bean proteins and animal milks: An inquiry into substitution viability

To clarify the comprehensive disparities in quality between bean- and milk-based set-type yogurts, this investigation undertook a thorough evaluation of the physicochemical and structural attributes of yogurts derived from three bean beverages with 12 g/100 mL (pea, fava bean, and chickpea) and three animal milk sources (Holstein cow, Jersey cow, and goat). The outcomes indicated that bean-based yogurts exhibited a reddish and had high adhesiveness and low tan δ, as well, the proportion of β-sheet declined and gels characterized by a more compact and dense protein structure with a high water-holding capacity (90–100%). Conversely, milk-based yogurts exhibited higher acidity and lower pH under identical fermentation temperature and post-ripening time conditions. Additionally, the proportion of β-sheet increased and gels featured a porous network structure with reduced water-holding capacity. Notably, fava bean yogurt demonstrated the highest adhesiveness (5.90 ± 0.03 N*s), hardness (4.76 ± 0.01 N), and apparent viscosity, and goat yogurt showcased notable cohesiveness (0.83 ± 0.02) and lowest viscosity and distinct wire drawing characteristics among the tested samples. Fava bean yogurt and Jersey cow yogurt garnered greater acceptability through sensory analysis. These findings underscore the contrasting attributes of bean- and milk-based yogurts, thereby contributing to the development of set-type yoghurts with different bean proteins.

Effect of protein-glutaminase on the texture, rheology, microstructure and sensory properties of skimmed set-type yoghurt.

The effects of enzymatic deamidation by protein-glutaminase (PG) on the texture, rheology, microstructure, and sensory properties of skimmed set-type yoghurt were studied. The proportion of small-particle size milk protein micelles (10-50nm) increased significantly from 0 to 99.39% after PG deamidation. Cryo-SEM results revealed that PG-treated yoghurt had a denser and less open 3D structure. PG was effective at inhibiting post-acidification during storage at 4 ℃. The water holding capacity of PG-treated yoghurt (0.12 U·mL-1) increased by more than 15%. The fluidity and viscosity of yoghurt were significantly improved with increasing PG dose. Sensory evaluation revealed that PG (0.06 U·mL-1) significantly improved the smoothness and creaminess of skimmed set-type yoghurt, which corresponded to the pastiness in texture. In summary, PG can effectively address the problems of post-acidification, gel fracture, and flavors change in skimmed set-type yoghurt, providing new applications for PG in the food industry.

Fortification of goat milk yogurt with goat whey protein concentrate – Effect on rheological, textural, sensory and microstructural properties

Goat milk and its products are valuable sources of nutrients and are good substitutes for cow milk products due to their hypoallergenicity. However, goat milk forms weak gels and it is often difficult to achieve acceptable texture and stability of set-type yogurt. The possibility of using goat milk whey protein concentrate (0.35% w/v and 0.7% w/v, WPC10 and WPC20, respectively) to improve the texture and stability of goat set-type yogurt (control WPC0) was investigated. The rheological properties of the yogurts were analyzed using oscillatory rheometry. The texture, induced syneresis, microstructure and sensory properties of the yogurts were studied after 1 and 21 days of cold storage. Mineral content, starter culture viability, and DPPH* radical scavenging activity of the yogurts were evaluated. The WPC20 yogurt exhibited improved elasticity and consistency, while the WPC10 yogurt was firmer and had a brittle structure but was rated better by the sensory panel after production, indicating preference towards short texture for set-type yogurts. The addition of WPC reduced syneresis and contributed to the viability of starter bacteria during storage but had no effect on the DPPH*- RS activity of the yogurts in the examined range. Fortification of goat milk with goat WPC could be successfully used as a method to improve texture, flavor, and stabilize goat yogurt during storage.

Properties of Yogurts Enriched with Crude Polysaccharides Extracted from Pleurotus ostreatus Cultivated Mushroom

Increasingly, consumers are looking for products with specific nutritional and health-promoting properties. The answer of the producers for this demand is fortified food. The raw material that can be used to enrich food is, among others, mushrooms. Crude water soluble polysaccharides (cWSP) were isolated from fruiting bodies of Pleurotus ostreatus (oyster) mushroom. Chemical analysis showed that they consisted mainly of carbohydrates (~61%), protein (~9%) and phenolics (~0.8%). The isolated cWSP were used to obtain enriched cow milk set yogurts. cWSP were added at the concentration of 0.1%, 0.2%, 0.3%, 0.4% and 0.5%, and milk containing no cWSP was prepared as the control. All of the variants were fermented via applying two commercially available culture starters. The addition of cWSP led to a drop in pH in the case of one starter culture. Also, the decline in total soluble solids (TSS) content was higher where cWSP was used for the enrichment. Texture profile analysis (TPA) revealed that parameters of hardness and gumminess increased along with the concentration of cWSP (reaching values approximately 7–8 times higher, compared to the control). A significant increase in syneresis level (proportional to cWSP concentration and ranging from ~10% to ~50%) was also observed after the fermentation. Fortifying milk with cWSP led to a slight increase in antioxidant capacity in FRAP assay (up to ~12%) and ABTS assay (up to ~23%). The results demonstrate that using cWSP to enrich set-type yogurts is fairly limited.

Effects of Guarana Aqua Extracts on Fermentation Kinetics and Quality Properties of Set-Type Yogurts

The combination of bioactive phytochemicals with yogurt in the form of plant extracts or essential oils stimulates the scientific community’s interest and consumers’ preferences. Extracts from guarana are considered bioactive agents and have important health protective properties. In this study, concentrations of guarana aqua extracts 0%, 0.5%, 1%, 2%, 3%, and 4% w/w were added to milk and yogurt fermentation kinetics, acidity, color, water-holding capacity, hardness, and microstructure and were evaluated. The presence of guarana aqua extract reduced the time needed for the completion of yogurt fermentation compared to the control samples. A drop in L ∗ and an increase in a ∗ parameters were also observed with increased guarana aqua extract concentrations. The lowest concentration of guarana aqua extract decreased titratable acidity, hardness, and syneresis. While different casein networks were observed in microscopy, yogurt without and yogurt with 3% w/w guarana extract had the same acidity and hardness. Finally, this research indicates the suitability of guarana extracts in the production of functional set-type yogurt and increases the knowledge on the effects of plant extracts on milk fermentation and yogurt quality characteristics.

Physicochemical and antioxidant properties of set-type yogurt supplemented by lyophilized water-soluble Melastoma dodecandrum extract-bearded chitosan-coated nutriosomes

In this study, the physicochemical and sensorial properties of set-type yogurt (STY)-enriched with water-soluble Melastoma dodecandrum Lour. fruit extract (MDLE) loaded nano-nutriosomes (MDLE-NU) or chitosan-coated nano-nutriosomes (CH-MDLE-NU) powder were investigated during 21 days of cold storage at 4 ± 2 °C. The results showed that MDLE powder has a high amount of phenolics, flavonoids, anthocyanins (59.42, 38.61, and 2.10 g/100g, respectively), and antioxidant activity ranging from 54.12 to 71.37 g/100g. MDLE successfully encapsulated in NU and CH-NU, where encapsulation efficacy reached 96.92% and particle size ranged from 144.57 to 172.30 nm with an acceptable range of PDI (<0.3). However, the commercial food custom of normal NU is still challenging, therefore, freeze-drying of MDLE-NU and CH-MDLE-NU can make their usage applicable. Our results showed that adding MDLE-NU and CH-MDLE-NU powder to STY significantly (p < 0.05) improved the color, water holding capacity, microstructure, texture, and sensory evaluation, as well as reduced whey syneresis, and losing fat globules of STY. Despite MDLE powder-enriched STY showing higher polyphenol content and antioxidant activity than MDLE-NU or CH-MDLE-NU, nutriosomes systems protect bioactive compounds of MDLE against unfavorable conditions in yogurt during cold storage. In which the reduction of total phenolics, total flavonoids, and total anthocyanins from STY-MDLE at the end of storage (21st day) was 2.7, 4.82, and 17.4%, while was 1.02, 2.6, and 3.03%, in STY–CH–MDLE-NU, respectively. This study indicates that MDLE is a promising ingredient to produce functional foods, besides, nutriosomes systems are a promising nanocarrier to encapsulate and protect the bioactive compounds.

Effects of ultrasonic processing on the quality properties of fortified yogurt

This study evaluated the effect of ultrasonic processing on functional yogurts fortified with banana-resistant starch (BRS) and green papaya powder (GPP). Ultrasonication technology (80% amplitude, 8 min at 20 kHz frequency) was utilized as an alternative to conventional thermal treatment (85 °C, 30 min) to improve functional yogurts' physical and textural properties. A total of 6 set-type yogurt groups were prepared by ultrasonication (UT) and conventional treatment (CT). Based on the textural studies and correlation (Pearson’s) plots, fortified and UT samples were more stiff, firm, sticky, adhesive, and viscous (least elastic) compared to the CT samples. All of the tested yogurts maintained a remarkable number of viable colony counts (≥7.23 log CFU/mL) during the storage. Ultrasonication significantly (p < 0.05) changed the L, a*, and b* color values. The ultrasonic processing reduced whey syneresis and improved the water-holding capacity in fresh and stored yogurts. Further, it retained the fatty acid profile of fortified yogurts. However, ultrasonication negatively affected, i.e., reduced the total polyphenol content and antioxidant activity of yogurts as compared to the conventionally (thermal) treated counterparts. Overall, ultrasound technology can be a potential alternative to thermal treatment for the improved quality and safety of fortified yogurts.

Sensory evaluation and physicochemical properties of set-type yoghurt fortified with andean lupin (Lupinus mutabilis) proteins

Abstract. The aim of this study was to evaluate the sensory characteristics and the physicochemical properties of high-protein yoghurt fortified with Andean lupin (Lupinus mutabilis) protein concentrate. Formulations with 0.5, 1 and 1.5% of protein concentrate (containing 69% proteins, 4% fats and 21% carbohydrates) were obtained using a commercial starter culture and cow´s milk. The acceptability for colour, flavour, texture and taste was evaluated with a hedonic 9-point scale and 100 adults aged between 18-59 years. Participants selected the attributes more convenient to describe the yoghurts using the CATA (Check-All-That-Apply) test. The chemical composition, pH and acidity as well as the textural properties were evaluated. The yoghurt with 0.5% lupin protein concentrate was acceptable according to the sensory attributes. The protein concentrate, when adding at 1 and 1.5%, increased the bitterness, the residual taste and astringency of formulations. The pH values and lactic acid content in fortified products were similar to the control sample, however the syneresis was lower. The yoghurt with 0.5%. The addition of fruits, cereals or honey could be a strategy to increase the acceptability according to participants´ perceptions. The use of yoghurt as dressings in salads could also be a novel form of consumption.The set-type yoghurt fortified with Andean lupin proteins could be alternatives to increase the daily intake of proteins, however some sensory properties should be optimized

Fortification of Yoghurt with Xanthan Gum Biosynthesized from Grape Juice Pomace: Physicochemical, Textural and Sensory Characterization

The impact of adding xanthan gum (0.05, 0.1 and 0.2%) biosynthesized from grape juice pomace on the physicochemical characteristics (pH, titratable acidity, total solid, water holding capacity and syneresis) of set-type yoghurt was examined during 21 days of storage period at 4 oC in this study. Textural, color (L*, a* and b*) and sensory attributes (appearance, color, texture, taste and odor) were also assessed in samples with and without biosynthesized xanthan gum. The textural properties and water-holding capacity of the yoghurt were significantly (p0.05) between the samples at the end of storage, except for the sample with 0.2% xanthan gum. The addition of the highest concentration of xanthan gum increased the a* and b* values while decreasing the L* value (p 0.05) between BX0.1% and BX0.2%, the samples with the lowest L* value. The addition of biosynthesized xanthan had no significant effect (p&gt; 0.05) on the total solid, protein and ash content of yoğurt. Besides, the biosynthesized xanthan gum had no negative impacts on the sensory characteristics of yoghurt, except for the appearance. The findings indicated that biosynthesized xanthan may be a desirable additive since it enhances the physical characteristics of yoghurt without affecting its nutritional value or sensory properties.

Physicochemical, Microbiological, and Sensory Properties of Set-Type Yoghurt Supplemented with Camel Casein Hydrolysate

The microbiological, rheological, and sensory properties of set-type yoghurt were investigated in the presence of camel and cow casein hydrolysates produced by the action of trypsin enzymes. The hydrolysates significantly decreased the fermentation and coagulation time of the yoghurt production. The rate of pH decrease was significantly (p &lt; 0.05) higher in samples treated with cow casein hydrolysate in comparison with control samples. Compared with the control, the cell growth of the yoghurt culture increased with the supplementation of the casein hydrolysate. Moreover, the survival of lactic acid bacteria (LAB) was enhanced by the addition of hydrolysates. The fortification of cow milk with camel and cow casein hydrolysates contributed to a significant improvement of the rheological and sensory properties of yoghurt. In conclusion, camel and cow casein hydrolysate could be used as a supplement in set-type yoghurt production with a potential beneficial effect on fermentation time, survival of total bacterial count, and overall acceptability.