Search Results (84)

The incorporation of Spirulina platensis has been studied as a strategy to enrich food with bioactive compounds. Recent studies have expanded the use of Spirulina in yogurts, seeking to combine its nutritional value with the practicality of functional foods. This study evaluated the physicochemical and bioactive compounds characteristics of yogurt incorporating commercial and agglomerated (with 30% maltodextrin, efficient carrier agent, in a fluidized bed) Spirulina platensis powder, at concentrations of 0.5–2.0% (w/v) prior to fermentation. This study is novel as it is the first to report the incorporation of S. platensis agglomerated in a fluidized bed into yogurt. Fermentations were carried out at 42 °C for 5 h and then the stirred yogurts were stored at 4 °C for 28 days for stabilization. All yogurts obtained achieved characteristic values according to the Brazilian Normative Instruction 46/2007 with total acidity (0.6–1.5%), pH (3.5–4.6), and viable lactic bacteria of at least 10⁶ CFU.g⁻¹, without significantly affecting the quality of the final product or the activity of lactic acid bacteria. For the nutritional composition, it was observed that the greater the amount of cyanobacteria incorporated, the higher the concentrations of proteins (4.2–5.6%) and ashes (1.3–1.8%) in the product, and for the bioactive compounds, the phenolic compounds ranged between 2.98 and 14.96 mg.100 g⁻¹ and significantly enriched the yogurt with phycocyanin (2.19–3.65 mg.100 g⁻¹), β-carotene (4.73–6.37 mg.100 g⁻¹), and chlorophyll a (12.39–13.77 mg.100 g⁻¹), for the formulations using commercial and agglomerated S. platensis powder. Agglomeration improved the stability of bioactive compounds after fermentation and stabilization processes of the yogurts. Also, it was found that the agglomerated S. platensis powder preserved a higher amount of bioactive compounds in the yogurt, which fulfills one of the main objectives of incorporating this cyanobacterium. Full article

Yogurt fortification with purslane (Portulaca oleracea L.) can improve its health benefits, but it may alter the fermentation step and its final properties. Thus, the current study investigated the suitability of Fourier Transform-Near Infrared (FT-NIR) spectroscopy for in-line monitoring of lactic acid fermentation of purslane-fortified yogurt compared with fundamental rheology. Changes in the yogurt properties during storage were also assessed. Set-type yogurts without and with lyophilized purslane leaves (0.55%) were produced and stored at 4 °C for up to 18 days. Lactic acid bacteria concentrations before and after fermentation at 43 °C for 2.5 h showed that the presence of purslane did not interfere with bacterial growth. The purslane addition increased the milk viscosity, resulting in a yogurt with complex modulus values higher than those of the reference sample (360 vs. 172 Pa). The elaboration of spectral data with Principal Component Analysis and the Gompertz equation enabled calculation of the kinetic critical points. Applying the Gompertz equation to the rheological data, it was evident that FT-NIR spectroscopy detected earlier the fermentation progression (the critical times were about 18% earlier on average), thus enabling better control of yogurt production. No significant changes in microbial or textural properties were noted during yogurt storage, demonstrating that purslane addition did not affect the product stability. Full article

Probiotics and phenolic compounds provide benefits to humans when they are consumed in adequate amounts. However, these materials are not very stable and can easily be degraded during processing and storage; so, they must be protected. This study evaluated the encapsulation of Lactiplantibacillus fabifermentans BAL-27 ITTG and phenolic compounds from coffee husks via alginate beads. The research considered variables such as alginate concentration (1.5% and 3%), crosslinking time (8 and 20 min), and the inclusion of chitosan. A 2³ factorial design was employed, and the effects were analyzed via ANOVA (p < 0.05). The encapsulation efficiency of the probiotic exceeded 80%, and its viability following gastrointestinal simulation ranged from 73.65% to 85.34%. The phenolic compounds achieved encapsulation efficiencies of up to 20%. In yogurt, the alginate beads maintained probiotic viability at approximately 9 Log₁₀ CFU/g and preserved the stability of the antioxidant compounds over 28 days. Moreover, the incorporation of beads did not adversely affect the physicochemical properties or sensory acceptance of the yogurt, supporting their potential application in functional foods. Full article

Yogurt is a highly consumed dairy product valued for its nutritional and probiotic properties. Its production involves the use of lactic acid bacteria, which drive biochemical transformations during fermentation. Optimizing fermentation time without compromising yogurt quality is essential for improving processing efficiency. Pulsed electric fields (PEFs) constitute a promising technology that stimulates microbial activity. In this study, a yogurt starter inoculum suspended in milk (IM) with different fat content (0.5–2.8%) was treated with low-intensity PEFs (1 kV/cm, 800–1600 µs) to enhance fermentation kinetics. pH, soluble solids, lactose, lactic acid, and riboflavin concentrations were monitored during 6 h, comparing PEF-treated IM (PEF-IM) and untreated IM (C-IM). PEF-treatments applied to IM reduced the fermentation time of inoculated milk by 4.3–20.4 min compared to C-IM. The lowest fermentation time (5.1 ± 0.16 h) was observed in milk added with PEF-IM (2.8% fat) treated at 1 kV/cm for 1600 µs. Milk inoculated with PEF-IM exhibited enhanced lactose consumption (1.6–3.1%) and higher lactic acid production (7.2%) than milk with C-IM. Riboflavin concentration (0.9–7%) decreased between 2 and 4 h, but it stabilized at the end of fermentation. Obtained results suggest that PEFs promote reversible electroporation in microbial cells, facilitating nutrient uptake and acidification, making it a promising assisted-fermentation approach to improve yogurt production. Full article

The swift progression of nanotechnology has transformed the food and dairy industries through the facilitation of functional foods, nutraceuticals, and antimicrobial systems. This review examines the environmentally friendly synthesis of nanoparticles (NPs) through the utilization of microorganisms, offering a sustainable and biocompatible alternative to traditional physical and chemical approaches. This study primarily aims to investigate the contemporary trends, mechanisms, and microbial species associated with NP biosynthesis, as well as to evaluate NPs’ techno-functional applications in food and dairy processing. The specific objectives encompass analysis of the synthesis pathways—both intracellular and extracellular—utilized by bacteria, fungi, yeasts, and algae. Additionally, an evaluation of the physicochemical properties and biological activities (including antibacterial, antioxidant, and antifungal effects) of synthesized NPs will be conducted, alongside the identification of their potential applications in food preservation, packaging, and fortification. The review emphasizes notable advancements in laboratory-scale applications, especially concerning yogurt fortification, biofilm suppression, and antimicrobial food coatings. Nonetheless, commercial application is constrained by issues related to scalability, purification, stability, regulatory adherence, and toxicity evaluation. Future investigations ought to focus on enhancing bioreactor systems, leveraging microbial consortia, utilizing food and agricultural waste as substrates, and implementing omics technologies to elucidate biosynthetic mechanisms. Furthermore, the standardization of synthesis protocols and the improvement of regulatory frameworks will be crucial in closing the divide between experimental achievements and NPs’ application in industry. In a nutshell, the microbial-mediated green synthesis of NPs offers a promising pathway for the advancement of safe, sustainable, and functional innovations within the food and dairy sectors. Full article

Lactic acid bacteria (LAB) isolated from plant sources are gaining increasing attention due to their potential probiotic and postbiotic functionalities. In the present study, Limosilactobacillus fermentum isolated from Prunus padus (bird cherry) was evaluated for its physiological, functional, and technological attributes for application in fermented dairy products. The strain was isolated through anaerobic fermentation and identified using API 50 CHL and 16S rRNA sequencing. Its acid tolerance, antioxidant capacity, antibacterial effects, and hemolytic activity were assessed. The cell-free supernatant (CFS) was evaluated for thermal and pH stability. Fermentation trials were conducted using both mono- and co-culture combinations with the commercial yogurt starter strain YC-380. Physicochemical properties, viable cell counts, and viscosity were monitored throughout fermentation and refrigerated storage. The L. fermentum isolate exhibited strong acid resistance (48.28% viability at pH 2.0), non-hemolytic safety, and notable DPPH radical scavenging activity. Its CFS showed significant antibacterial activity against five Escherichia coli strains, which remained stable after heat treatment. Co-cultivation with YC-380 enhanced fermentation efficiency and improved yogurt viscosity (from 800 to 1200 CP) compared to YC-380 alone. During 24 days of cold storage, co-cultured samples maintained superior pH and microbial stability. Additionally, the moderate acidification profile and near-neutral pH of L. fermentum created favorable conditions for postbiotic compound production. These results indicate that L. fermentum derived from P. padus holds considerable promise as a functional adjunct culture in yogurt production. Its postbiotic potential, technological compatibility, and heat-stable bioactivity suggest valuable applications in the development of safe, stable, and health-promoting fermented dairy products. Full article

During the preparation of beer wort, significant amounts of waste raw materials, such as brewers’ spent grain (BSG), are generated. In line with the zero-waste approach, a processing technology for BSG was developed to valorize this by-product. The developed method involves obtaining a BSG extract (plant-based milk), followed by filtration to remove insoluble residues and subsequent fermentation to produce vegan BSG-based yogurt-like products, with and without the addition of sucrose, as well as pectin, guar gum, and konjac gum as stabilizers. The samples were analyzed for pH, moisture and protein content, water activity (Aw), color, viscosity, and syneresis, and were also subjected to an organoleptic evaluation. Fermentation with starter cultures yielded BSG-based yogurt-like products with an optimal pH (~4.0), which, combined with Aw values below 0.95, ensures microbiological safety by inhibiting the growth of pathogenic and spoilage microorganisms. Due to phase separation, the use of stabilizers was necessary to achieve a yogurt-like texture. Their application also contributed to a reduction in syneresis—sometimes even preventing its occurrence—and led to an increase in viscosity, which ranged from 0.162 to 0.463 Pa·s, depending on the stabilizer used. The moisture content of fermented BSG extracts ranged from 88.2% to 91.7%. All samples showed similar protein content, approximately 50% on a dry matter basis. Furthermore, organoleptic assessment (5-point scale) revealed that sensory characteristics varied depending on the stabilizer and sugar used. The yogurt-like variant formulated with 0.5% pectin and 1% sucrose received the highest acceptance score (4.0), indicating good sensory quality. Full article

In pursuing functional foods that promote health, nanoliposomal carriers have been used to enhance the stability and functionality of dairy products such as yogurt, promising therapeutic benefits. This study aimed to evaluate the impact of fucoxanthin-loaded nanoliposomes in yogurt on its antioxidant, physicochemical, and rheological properties under cold storage (21 days). Fucoxanthin-loaded nanoliposomes were prepared using the ultrasonic film dispersion technique and added at concentrations of 0%, 5%, and 10% in the yogurt (Y-C, Y-FXN-5, Y-FXN-10). Homogeneous and uniform nanoliposomes (98.28 nm) were obtained, preserving their integrity and functionality and ensuring the prolonged release and bioavailability of fucoxanthin. Y-FXN-10 maintained the highest antioxidant activity according to the DPPH (52.96%), ABTS (97.97%), and FRAP (3.16 mmol ET/g) methods. This formulation exhibited enhanced erythroprotective potential, inhibiting hemolysis, photohemolysis, and heat-induced hemolysis. However, viscosity and firmness decreased, affecting the texture and appearance. Sensory properties such as the color, flavor, aftertaste, texture, and overall acceptance improved with the 10% fucoxanthin-enriched yogurt formulation. These results suggest that nanoliposomes are suitable for carrying fucoxanthin. Their incorporation into food matrices is critical to developing functional foods. Regulatory approvals and consumer perceptions regarding nanotechnology-based products must be addressed, emphasizing their safety and health benefits. Full article

The aim of this study was to develop a functional yogurt enriched with encapsulated probiotics with viable cell counts exceeding 10⁷ CFU/g while preserving sensory quality, thereby enhancing health benefits and potentially preventing intestinal barrier dysfunction. Lacticaseibacillus rhamnosus LGG^® was encapsulated in prebiotic-based matrices for enhanced stability, bioavailability, and controlled release under gastrointestinal conditions. Two encapsulation methods were investigated—the innovative electrohydrodynamic processing (electrospraying) method and conventional freeze drying. The encapsulation matrices were composed of inulin and whey protein isolate. Encapsulation efficiency was determined via microbiological analysis, and the encapsulated structures were characterized using scanning electron microscopy. The efficacy of the encapsulated probiotics was further assessed through exposure to gastrointestinal conditions. Electrosprayed LGG^® provided the highest survival rates, up to 76%. Storage stability was evaluated at 4 °C for 105 days and after incorporation in commercial yogurt for 60 days. The sensory characteristics of the different yogurt products were also evaluated. The final products presented acceptable sensory features and final viable counts of 1.6–1.8 × 10⁷ CFU/g. The denser structure of electrosprayed LGG^® led to even higher protection. The findings highlight the potential of encapsulation—particularly electrospraying—in developing functional foods with improved probiotic delivery systems, paving the way for health-oriented dairy products. Full article

Plant powders have exhibited great potential to enhance the antioxidant activity of yogurt. This study aims to evaluate the effects of hawthorn powder (1.0–3.0%, w/w) addition on the antioxidant activity and physical properties of set-type yogurt. The results demonstrated that yogurt containing 1–2% hawthorn powder exhibited improvements in quality, water-holding capacity, and texture. Notably, the antioxidant activities, including the DPPH radical, hydroxyl radical scavenging rate, and Fe²⁺ chelating activity, reached 68.2 ± 4.9%, 81.6 ± 0.5%, and 72.2 ± 2.0%, respectively, and were higher than those of ordinary yogurt. Microstructural observation revealed that appropriate hawthorn powder concentration promoted homogeneous protein network formation, contributing to improved texture stability. In conclusion, this research is of interest to the development of functional dairy products. Full article

This study examines the impact of added elderberry (EDB) extract on the physico-chemical, microbiological, and sensory properties of yogurt over a 21-day storage period. Two separate experiments were conducted: the first focused on testing concentrations of 0.05%, 0.1%, 0.2%, and 0.5% (w/w) EDB extract for impoving antioxidant properties and replacing potassium sorbate, a chemical preservative commonly used in dairy products, while the second aimed to enhance the bioactive compounds’ concentration by adding 0.5% EDB extract, and to assess the effect of a sweetener (agave syrup) on the sensory profile. Both experimental approaches demonstrated a significant increase (p < 0.01) in total phenolic content. In the first experiment, there was approximately 2.6 times more total phenolic content compared to the control (with a maximum of 11.71 mg GAE/100 g for the sample with 0.2% EDB extract), and about 6 times more with the addition of 0.5% EDB extract and agave syrup (with a maximum of 25.29 mg GAE/100 g). Additionally, the IC₅₀ value decreased for all samples with EDB extract, suggesting enhanced antioxidant activity. Specifically, the antioxidant activity was approximately 3.3 times higher for the control for samples obtained from homemade yogurt with EDB extract, and about 8 times higher for samples obtained by adding EDB extract to commercial yogurt, compared to their respective controls. The high stability of bioactive compounds during the storage period highlights the potential of EDB extract as a functional antioxidant ingredient. Microbiological analysis confirmed the safety of the yogurt, with lactic acid and mesophilic bacteria showing stable counts and minimal declines over time. In the first experiment, a reduction of about 2.3 CFU/g was observed from day 0 to day 21 in samples with 0.1% and 0.2% EDB extract, while the control sample showed a reduction of 1.84 CFU/g. However, the control sample recorded the growth of psychrophilic bacteria, yeasts, and molds. In the second experiment, the samples with 0.5% EDB extract showed an average reduction of approximately 0.35 CFU/g, while the control showed a reduction of 0.51 CFU/g, maintaining stable counts and no detectable growth of psychrophilic bacteria, yeasts, molds, or coliforms. Additionally, the inclusion of different concentrations of EDB extract, along with the combination of a higher concentration of EDB extract and agave syrup, improved the yogurt’s sensory attributes, thereby enhancing consumer acceptance. For the first experiment, 68% of the panelists expressed their preference for the samples with EDB extract, and 10% preferred the control sample. In the second experiment, 49% preferred the sample with 0.5% EDB extract and agave syrup, while 23% preferred the control sample. These findings support the integration of EDB extract into yogurt formulations to boost antioxidant properties while preserving microbiological stability. Future research should explore the potential health benefits and long-term effects of these functional dairy products. Full article

The growing demand for plant-based and hybrid dairy–plant beverages has driven interest in optimizing their fermentation processes. This study investigates the effects of selected lactic acid bacteria (LAB) cultures on the quality characteristics of fermented dairy, dairy–oat, and oat beverages. The term ‘dairy-oat beverage’ refers to a hybrid product composed of cow’s milk and an oat-based drink in a 1:1 ratio. Cow’s milk, an oat beverage, and a 1:1 mixture of both were inoculated with traditional yogurt cultures (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) and/or probiotic strains (Lactiplantibacillus plantarum 299v and Lactobacillus acidophilus La-5). Fermentation was conducted for 6 h at 37 °C, followed by 28 days of cold storage. pH, texture (hardness and adhesiveness), syneresis, carbohydrate content, and bacterial viability were assessed. The selection of lactic acid bacteria cultures had a significant impact on the quality attributes of the beverages. Both the bacterial culture type and the base material played a crucial role in determining the beverages’ texture, stability, and overall quality. Mixed bacterial cultures exhibited higher hardness, while milk and dairy–oat samples fermented with the yogurt culture demonstrated better structural stability. Fermentation influenced sugar levels, and bacterial viability depended on the beverage type and storage conditions. The selection of lactic acid bacteria cultures significantly impacts the quality of fermented beverages. Further optimization of bacterial culture combinations could improve these products’ stability and sensory properties. Full article

Production of plant-based products is still on the rise. There is a need for new plant-based dairy alternatives in the food market due to lactose intolerance, allergens to dairy and nuts and a rise in gluten-free products. Rice is a key source for these types of products because it is hypoallergenic. This study focused on the comparison storage stability and in vitro digestion of milk-based yogurt (MY) to yogurt alternatives (YA) made with four different rice flours. YAs and MY were prepared using L. delbrueckii and S. thermophilus for fermentation and L. rhamnosus (LGG) as a probiotic. Samples were stored refrigerated for up to 28 days and analyzed for titratable acidity, pH, color, syneresis, viscosity and bacterial counts every seven days. Probiotic survivability was tested under simulated gastric and intestinal conditions. YAs had lower syneresis than MY. There were few changes in color over time. Titratable acidity was lower in YAs (0.1 to 0.5%) than in MY (1%) while pH decreased in all samples during storage. Bacteria counts were stable throughout storage in all samples. MY had higher counts of LGG at the beginning of storage which significantly decreased during exposure to in vitro gastric conditions. Under in vitro intestinal conditions, both the white rice flour YAs and the MY retained the highest levels of LGG. This study indicated that it is possible for YAs made with rice flour to be stable overtime and with survivability of probiotic bacteria under gastric conditions. Full article

Fermented milk products, such as yogurt, undergo significant changes in their physicochemical, sensory, textural, and rheological properties based on fermentation time and storage. This study investigated how different fermentation times (4, 5, 6, 7, and 8 h) and storage durations (1, 7, 14, and 21 days) influenced the characteristics of probiotic yogurt made from sheep milk, cow milk, and a blend of both. Using 2% of each of Lactobacillus rhamnosus GG, Lactobacillus bulgaricus, and Streptococcus thermophilus, fermentation was conducted at 40 °C. The results demonstrated that fermentation time and storage had a significant impact on pH, acidity, total bacterial count (TBC), water-holding capacity (WHC), syneresis, and sensory attributes. Probiotic yogurt made from sheep milk, when fermented for 6 h and stored for 1 day, exhibited the highest acidity (109.42 °T), total bacterial count (TBC) (592.41 × 10⁶ cfu/g), water-holding capacity (WHC) (658.42 g/kg), and sensory score (8.62), with a final pH of 4.25. In contrast, cow milk yogurt, fermented for 5 h and stored for 14 days, had the lowest acidity (81.76 °T), TBC (305.75 × 10⁶ cfu/g), and sensory score (6.24), with a pH of 4.44. The blended yogurt, fermented for 6–7 h and stored for 1 day, showed intermediate values, with an acidity of 89.55 °T, TBC of 284.33 × 10⁶ cfu/g, and a sensory score of 7.24. Syneresis varied from 18.06 to 19.67, with cow milk yogurt, fermented for 6 h and stored for 1 day, exhibiting the highest level. These findings highlight the impact of fermentation time and storage on yogurt quality, with optimized conditions enhancing texture, stability, and sensory appeal. These variations in yogurt properties highlight the critical role of fermentation time and storage conditions in defining texture and stability. Notably, the optimal fermentation times for achieving desirable physicochemical and sensory properties were found to be 6 h for sheep milk yogurt, 5 h for cow milk yogurt, and 6–7 h for the blend. The findings emphasize the importance of milk composition and fermentation conditions in optimizing probiotic yogurt quality. Furthermore, the study underscores the potential of sheep milk in producing yogurt with superior sensory and textural characteristics, offering promising opportunities for the development of high-quality functional dairy products. Full article

This study investigated the potential of turmeric powder as a functional additive to yogurt, specifically focusing on its effect on the antioxidant capacity and phenolic content. Yogurt samples were prepared with 0.5% and 1.0% turmeric powder, leading to increases in pH, antioxidant capacity (from 10% to 51%), and phenolic content (from 1.39 mg to 30.20 mg per 100 g) compared to plain yogurt. While turmeric showed no antibacterial effects in vitro, its addition resulted in a reduction in yogurt bacteria counts, which remained within the regulatory limits. However, exposure to gastric pH and bile salt conditions led to reductions in the antioxidant activity and total phenolic content of turmeric-enriched yogurt, indicating potential limitations in its stability during digestion. Sensory evaluations revealed a preference for plain yogurt; however, turmeric-enriched yogurts also achieved favorable acceptance scores. These findings indicate that turmeric incorporation can enhance the health benefits of yogurt, offering a promising option for consumers desiring functional dairy products. Full article