Development of an efficient stabiliser mixture for physical stability of nonfat unfizzy doogh

Investigation of rheological, physicochemical, and sensorial properties of traditional low-fat Doogh formulated

Doogh is a fermented beverage made from yoghurt with water and salt. Similarly, drinks based on yoghurt are available in different countries with varying degrees of dilution, fat content, rheological properties, and taste. In this project, the use of mathematical calculations in describing rheological parameters from traditional low-fat Doogh enriched with Caspian Sea (Huso huso) gelatin (0.4 w/v %), xanthan hydrocolloids (0.4 w/v %), and their mixture at a ratio of 0.2:0.2 w/v % studied. Also, serum isolation, pH, and sensory evaluation of samples were investigated. Also, the relationship between apparent viscosity and temperature of Doogh samples using the Arrhenius equation was studied. The sensory evaluation revealed that the overall acceptance scores of the samples containing gelatin, xanthan, mix, and control were 4.31, 4.33, 4.58, and 4.12, respectively. The study on serum separation value showed control sample (45.07) and mix sample (0.84) at the end of 30 days. On the first day, the pH of the Doogh samples decreased with the addition of hydrocolloids, and this trend was time dependent. pH reduction was higher in Doogh with gelatin than in other samples. Mathematical calculations showed that the low-fat Doogh is a non-Newtonian type and shear-thinning (Pseudoplastic) fluid. The activation energy was calculated between 11.65 and 19.15 kJ/mol. According to the obtained results, it concluded that the use of two hydrocolloid compounds improved the physicochemical and sensory characteristics of the low-fat Doogh samples. Also, the Ostwald-de Waele mathematical model had a high correlation with the rheological behavior of the samples.

A comprehensive review on yogurt syneresis: effect of processing conditions and added additives

Yogurt, produced by the lactic fermentation of milk base, is an important dairy product worldwide. One of the essential sensory properties of yogurt is the texture, and some textural defects such as weak gel firmness and syneresis likely occur in various types of yogurts, affecting consumer acceptance. In this regard, various strategies such as enrichment of milk-based with different additives and ingredients such as protein-based components (skimmed milk powder (SMP), whey protein-based powders (WP), casein-based powders (CP), and suitable stabilizers, as well as modification of processing conditions (homogenization, fermentation, and cooling), can be applied in order to reduce syneresis. The most effective proteins and stabilizers in syneresis reduction are CP and gelatin, respectively. Furthermore, yogurt's water holding capacity and syneresis can be affected by the type of starter cultures, the protolithic activity, production of extracellular polysaccharides, and inoculation rate. Moreover, optimizing the heat treatment process (85 °C/30 min and 95 °C/5 min), homogenization (single or dual-stage), incubation temperature (around 40 °C), and two-step cooling process can decrease yogurt syneresis. This review is aimed to investigate the effect of fortification of the milk base with various additives and optimization of process conditions on improving texture and preventing syneresis in yogurt.

Locust Bean Gum, a Vegetable Hydrocolloid with Industrial and Biopharmaceutical Applications

Locust bean gum (LBG), a vegetable galactomannan extracted from carob tree seeds, is extensively used in the food industry as a thickening agent (E410). Its molecular conformation in aqueous solutions determines its solubility and rheological performance. LBG is an interesting polysaccharide also because of its synergistic behavior with other biopolymers (xanthan gum, carrageenan, etc.). In addition, this hydrocolloid is easily modified by derivatization or crosslinking. These LBG-related products, besides their applications in the food industry, can be used as encapsulation and drug delivery devices, packaging materials, batteries, and catalyst supports, among other biopharmaceutical and industrial uses. As the new derivatized or crosslinked polymers based on LBG are mainly biodegradable and non-toxic, the use of this polysaccharide (by itself or combined with other biopolymers) will contribute to generating greener products, considering the origin of raw materials used, the modification procedures selected and the final destination of the products.

Production of synbiotic Doogh enriched with Plantago psyllium mucilage

Physical instability and loss of viability of probiotic bacteria are the most important problems in production of synbiotic Doogh. Some plant hydrocolloids have been recognised as effective components to prevent these problems. In this study the effect of Plantago psyllium mucilage (PPM) (0, 0.15%, 0.30%, 0.75% (w/w) on the physicochemical, microbial, and sensory properties of Doogh samples was evaluated by measuring phase separation, viscosity, flow behaviour, probiotic viability and sensory parameters. The results revealed that the stability of samples containing PPM were higher than samples without this hydrocolloid. By increasing the amounts of PPM, the viscosity of treated samples were increased compared to control sample. Herschel-Bulkley rheological model was an appropriate model for describing the flow behavior of Doogh formulated with PPM and the power-law rheological model was suitable model for describing the flow behavior of control samples. PPM had non-digestible food ingredients and improved the viability of Lactobacillus casei; therefore, this herbal mucilage may have prebiotic potential. Finally, the samples treated with 0.30% PPM on the 15th day were chosen as the best formulation for the production.

The stabilizing and prebiotic potential of water-soluble phase of bitter almond gum exudate in probiotic yogurt drink

Yogurt drinks can potentially be an appropriate medium for delivering probiotics to consumers. This study investigated the influences of the water-soluble fraction of bitter almond gum (SBAG) and its conjugate with sodium caseinate (SBAG-SC) compared to carboxymethylcellulose (CMC) and inulin, respectively, on the physical stability of casein micelles and the viability of the probiotic culture (Lactobacillus acidophilus La-5) in probiotic yogurt drink during cold storage. The addition of SBAG-SC conjugate to the drinks successfully prevented phase separation for a longer time than CMC. CMC-based drinks exhibited a strong shear-thinning response. Adding SBAG helped keep Lactobacillus acidophilus La-5 viable above the recommended level for probiotic products. However, the SBAG showed relatively less prebiotic property than inulin. This study demonstrated that SBAG-SC conjugate has a high potential for stabilizing applications in yogurt and yogurt products.