Mahmoud E. A. Hamouda

This study evaluated the effect of incorporating chia seed gel powder (CSGP) as a natural, clean-label stabilizer on the physicochemical, functional, microbiological, microstructural, antioxidant, and sensory properties of probiotic low-fat yogurt (PLFY) during 21 days of refrigerated storage. Six formulations were prepared using 0–2.5% CSGP, including Control (0% CSGP), YOG1 (0.5% CSGP), YOG2 (1.0% CSGP), YOG3 (1.5% CSGP), YOG4 (2.0% CSGP), and YOG5 (2.5% CSGP). Results showed that increasing CSGP levels noticeably enhanced the total solids, protein content, viscosity, hardness, and water-holding capacity of the PLFY (p < 0.05), while consistently reducing syneresis. Antioxidant activity also rose with higher CSGP concentrations, with YOG5 exhibiting the greatest DPPH scavenging activity (35.12%). Confocal laser scanning microscopy revealed a denser and more uniform protein network in PLFY fortified with CSGP, consistent with rheological measurements showing increased storage (G′) and loss (G″) moduli. Probiotic viability significantly increased (p < 0.05) in CSGP-added samples, indicating a potential prebiotic effect of CSGP. Sensory results demonstrated that although higher CSGP levels slightly darkened the yogurt color, body, texture, flavor, and total sensory scores improved markedly, with YOG5 gaining the highest total score (81.77). The results demonstrate that CSGP acts as a highly effective, multifunctional ingredient that enhances texture, stability, probiotic viability, and antioxidant capacity, making it a strong clean-label candidate for developing high-quality, functional probiotic low-fat yogurt.

The aim of this study was to investigate the effects of the addition of guar gum (GG) and xanthan gum (XG) on the proximate composition, texture, viscosity, syneresis, color characteristics, microbiological stability, sensory evaluation, rheological properties, and microstructure of a low-fat yogurt sample. The results showed that adding GG and XG at concentrations of 0.5 and 1% increased the hardness and viscosity of yogurt significantly (p < 0.05), with XG having a more pronounced effect. There was no significant difference (p > 0.05) in color characteristics between all treatments during the storage period. The viability of probiotics was enhanced in gum-supplemented yogurts, with XG providing better protection for Lactobacillus delbrueckii subsp. bulgaricus and Bifidobacterium bifidum during storage. Sensory evaluation results showed that XG samples gained higher scores as compared to GG samples. Rheological analysis revealed that both the hydrocolloids guar gum (GG) and xanthan gum (XG) significantly increased the parameters such as viscosity and yield stress of low-fat yogurt, with xanthan gum having a more pronounced effect on enhancing the flow behavior. Microstructural analysis using scanning electron microscopy revealed that XG supplementation improved the yogurt gel network, developing a more compact and cohesive structure; however, GG produced a looser and more dispersed network. Overall, both GG and XG enhanced the rheological, textural, and microstructural characteristics of low-fat yogurt, with XG showing superior effects on texture, gel structure, and probiotic stability.

This study investigated the effects of incorporating defatted rice bran (DRB) at different concentrations (0.5%, 1%, 1.5%, and 2%) on the quality, microbiological, and sensory characteristics of probiotic low‐fat yogurt (LFY) during a 21‐day storage period at 4°C. DRB is rich in dietary fiber, essential amino acids, vitamins, and bioactive compounds, and its addition aimed to enhance the nutritional and functional properties of LFY. LFY samples were evaluated for proximate composition, hardness, viscosity, syneresis, color characteristics, rheology, and sensory evaluation. Also, microbiological analysis includes total bacterial counts (TBC), Lactobacillus delbrueckii ssp. bulgaricus , Streptococcus thermophilus , Bifidobacterium bifidum counts. Results indicated that DRB addition significantly ( p < 0.05) increased probiotic counts, especially at 1% and 1.5% concentrations, with these samples maintaining higher bacterial stability over the storage period. DRB‐added LFY also showed improved nutritional profiles, with increased TS, protein, ash, fiber, and antioxidant activity. Additionally, hardness, viscosity, and rheology (G′ and G″) values significantly ( p < 0.05) increased with the addition of DRB, while syneresis significantly ( p < 0.05) decreased. However, higher DRB concentrations negatively affected the color, with lightness decreasing and the browning index increasing. This also impacted sensory characteristics, resulting in lower scores for color, flavor, and overall acceptability, particularly in LFY with 2% DRB. To conclude, moderate DRB addition (up to 1.5%) optimally balances the enhancement of probiotic and nutritional properties with acceptable sensory quality offering a viable strategy for producing functional low‐fat yogurt.

The increasing demand for functional and nutritious beverages necessitates the exploration of novel ingredients and formulations. This study evaluated the impact of supplementing chocolate milk with desert truffles powder and varying concentrations of gum arabic on its chemical composition, viscosity, color characteristics, antioxidant activity, and sensory attributes. Desert truffles powder was consistently incorporated at 2% across all treatments, while gum arabic concentrations varied from 0% to 1.5%. The results revealed significant enhancements in the nutritional profile, particularly in treatments with higher gum arabic concentrations, which showed increased solids-not-fat, protein, and carbohydrate contents. Additionally, the viscosity and shear stress values of the chocolate milk improved with the addition of gum arabic, enhancing its texture and stability. Color analysis demonstrated a darker and more intense coloration in samples with higher gum arabic levels. Antioxidant activity, assessed through total phenolic content, DPPH, and ABTS scavenging activity, was highest at moderate gum arabic concentrations but declined at higher levels. A high correlation was observed between total phenolic content and both DPPH and ABTS scavenging activities. Sensory evaluation indicated no significant differences in flavor, consistency, color, and overall acceptability across treatments, suggesting that the nutritional enhancements did not compromise sensory qualities. Overall, this study highlights that incorporating desert truffles powder and gum arabic can effectively improve the functional and nutritional properties of chocolate milk, presenting it as a viable option for health-oriented consumers.

The objective of this study was to determine the effect of XG addition on low-fat yogurt (LFY) properties. Pasteurized skimmed buffalo milk (SBM) was heated to 95 ± 2 °C for 16 s, cooled to 40 ± 1 °C, and then divided into six treatment lots. The treatments included the following: T1 (control), T2 (0.2% XG), T3 (0.4% XG), T4 (0.6% XG), T5 (0.8% XG), and T6 (1% XG). A proportion of 2% of a mixed starter culture from Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB), and Bifidobacterium bifidum (BB) in the ratio 1:1:1 was added. Yogurt was manufactured following the standard manufacturing protocol. Chemical composition and texture were determined at fresh time, while water-holding capacity (WHC), viscosity, and syneresis % were determined at 0, 7, 14, and 21 days of storage. Total bacterial counts (TBC), lactobacilli, streptococci, and bifidobacteria counts were determined at 0, 7, 14, and 21 days of storage. Sensory analysis was performed immediately upon the cooling stage (time zero) and then after 14 and 21 days of storage. The experiment was performed in trice. The results obtained showed that the addition of XG in LFY significantly (p < 0.05) decreases the pH, total protein (TP), and ash, and significantly (p < 0.05) increased the total solids (TS). Additionally, the addition of XG led to a significant (p < 0.05) increase in hardness, WHC, and viscosity; however, syneresis significantly (p < 0.05) decreased. The addition of higher amounts of XG led to a significant (p < 0.05) decrease in the TBC and led to a significant (p < 0.05) increase in counts of ST, LB, and BB during the first two weeks of the storage period. Sensory evaluation revealed that increasing the XG concentration up to 0.8% increased the product’s acceptability among panelists; however, further increasing the concentration to 1% had a detrimental impact on its acceptability. To conclude, this study showed that XG can be used as a stabilizer in the manufacturing of LFY as well as a prebiotic for starter culture and improve the quality of LFY.

This work aimed to study the effect of adding skim milk powder (SMP) and whey protein concentrate (WPC) to probiotic mozzarella cheese. Pasteurized cow milk was heated to 55 °C and divided into five parts: PMC1 (control), PMC2 (1% SMP), PMC3 (1.5% SMP), PMC4 (1% WPC), and PMC5 (1.5% WPC). After mixing powders in the respective concentrations in the treatments, the milk was cooled to 35 °C, and Bifidobacterium bifidum culture (5%) was added. Proximate analysis, calcium, soluble nitrogen (SN), total Bifidobacterium bifidum count, cheese yield, hardness, and meltability tests were carried out at 0, 14, and 28 days of storage. The mozzarella cheese samples with WPC added had higher acidity, total solids, and protein content than the mozzarella cheese samples with SMP added and the control samples during storage. The addition of WPC led to a significant increase (p < 0.05) in the count of Bifidobacterium bifidum during storage at 5 °C. The cheeses with WPC added had increased meltability, higher hardness, and higher browning on pizza compared to those of the mozzarella cheese with SMP added. A sensory evaluation showed that the addition of WPC increased sensory scores, compared to the addition of SMP. As storage time progressed, there was a significant (p < 0.05) increase in the Bifidobacterium bifidum, meltability, and sensory scores of PMC in all treatments.