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 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.