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Background: A lot of people consume traditional foods throughout the world, however there are concerns for their safety. The purpose of the current study is to evaluate the safety of traditional doogh (a traditional fermented dairy beverage) with respect to microbiological, chemical, and toxicological aspects. Methods: 89 samples of traditional doogh from Khuzestan province, Iran, were analysed according to microbiological ( Staphylococcus aureus, Echerichia coli, coliforms, mold and yeast), chemical (pH, total solid, fat, and salt content), and toxicological (aflatoxin M1, potassium sorbate, sodium benzoate, and natamycin) aspects. Results: Results showed that 89.88% of samples would be rejected according to the guidelines specified by the Institute of Standards and Industrial Research of Iran (ISIRI). 78 sample had higher mold and yeast than standard. The salt content of five out of 89 samples were higher than the established Iranian standard. Conclusion: The most challenging problem was mold and yeast contamination, indicating poor hygienic manufacturing conditions. However, the unfavorable conditions for microbial growth such as low pH may prevent the toxic metabolites formation, and therefore, consuming it presents no major concerns to public health. Nonetheless, the authors suggest that efforts should be made to improve hygienic conditions in traditional doogh manufacturing environments. [ABSTRACT FROM AUTHOR]

The consumption of locally produced organic foods has become a popular trend in those seeking better health through diet. Despite their proposed health benefits, there are concerns regarding the safety of these foods, as they may contain pathogens due to poor hygienic conditions during production. This study aimed to explore the microbial inhibitory effects of ewe milk, yogurt, and doogh prepared by nomads from Ghasr-e-Shirin region in Iran, and to identify the bacterial community of these products using next-generation sequencing of 16S rRNA gene. The antimicrobial activity of cell-free supernatants (CFSs) of samples were evaluated against 3 fungi and 5 bacteria by agar disc diffusion and broth microdilution assays. The findings of this research showed that there is great diversity of bacteria in milk collected by nomads. The most dominant bacteria were Enterobacteriaceae (49.16%) in milk. However, non-lactic acid bacteria were overtaken by Lactobacillus delbrueckii (99.9%) in doogh and yogurt. The CFSs of yogurt and doogh showed growth inhibitory activity against the microorganisms used in this study. [ABSTRACT FROM AUTHOR]

Background: Doogh is a traditional dairy product, which is widely used as a popular drink in the Middle East, in general, and in Iran, in particular. There has been no research study regarding its effects on vigilance and mental-cognitive performance so far; the present study aimed at investigating this effect. Objectives: The current study aimed at objectively evaluating the effect of Doogh (Yogurt drink) on attention, reaction time and vigilance-sleepiness of healthy young adults. Methods: In this repeated measurement study, participants included 17 healthy adults between 20 and 40 years old, with adequate night sleep and without any symptoms of daytime sleepiness that entered the clinical trial one at a time via public invitations. The intervention included drinking 250 cc of doogh or water in the morning or in the afternoon. Therefore, there were 4 interventions for each participant with random sequences, lasting 3 to 5 days. Right before and 1.5 to 2 hours after drinking each of the drinks, the participants were assessed using test of variables of attention (TOVA) and sleepiness test via the visual analogue scale (VAS). The data were analyzed by paired t test and Generalized Estimating Equation (GEE) model at the final stage. Results: Ten female and 7 male participants took part in the study. Doogh caused a significant increase in reaction time and commission error and reduced vigilance. These changes occurring after drinking doogh were significant in the afternoons, while they were insignificant in the mornings despite the fact that they lasted longer. There was no change regarding TOVA variables caused by water in any of the case. Although reduced level of vigilance was observed after drinking water, the differences weremoresignificant with regards to doogh and its post intervention comparison with water was meaningful. Conclusions: Dooghcaused sleepiness in the afternoon time along with a significant increase in reaction time and commission and omission errors. Regarding the cognitive effects of doogh, the timing and activity type of the drinker should be taken into account. Positive effects of drinking doogh on sleepiness and the risk of accidents caused by drinking it should be studied in other research projects. [ABSTRACT FROM AUTHOR]

Today, the increasing use of chemical preservatives in foods is considered one of the main problems in food industries. This study aimed to produce the pasteurised Doogh (Iranian yogurt drink) containing a nanoemulsion of essential oil (EO) with appropriate quality. A factorial test based on a completely randomised design with two treatments in three levels, including EO type (pennyroyal, Gijavash, and their equal combination) and a control sample was applied to assess the physicochemical and sensory properties of Doogh. The highest negative zeta potential and antioxidant activity percentage were observed in the sample containing the nanoemulsion of pennyroyal and enriched with a combination of two essential oils. The microbial evaluation results indicated that the total microorganism count was minimised in the Doogh containing the nanoemulsion of Gijavash. The nanoemulsions of pennyroyal and Gijavash can be added into Doogh formulation to produce a new product with maximum sensory acceptability., (© 2022 The Authors. IET Nanobiotechnology published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.)

Sodium benzoate and potassium sorbate are two common preservatives used in Iran, yet use of these preservatives in doogh (Iranian dairy-based drink) is forbidden according to national standards. The aim of this study was to consider the presence of these preservatives in doogh by high-performance liquid chromatography with UV detection (HPLC-UV). The method was performed using a C18 column and detection at 225 nm. The mobile phase contained ammonium acetate buffer (pH = 4.2) and acetonitrile (80:20 v/v). The survey included 130 samples of doogh for identification and quantification of the named preservatives. All samples contained sodium benzoate, but potassium sorbate was detected in only 13% of them. The means of benzoate and sorbate were 21.3 ± 2.7 and 13.3 ± 39.6 mg kg-1, respectively. The limits of detection were 2 and 40 ng g-1 for benzoate and sorbate, respectively. Results indicate that sodium benzoate may occur in doogh naturally. [ABSTRACT FROM AUTHOR]

Abstract: Among dairy products, Doogh, a traditional fermented acidified drink, has special status in Iran due to its health properties. However, the main physical problem of the product is its phase separation. Therefore, the aim of this study was to produce a stable and fiber-enriched pasteurized and non-pasteurized Doogh using gellan. Pasteurized Dooghs containing fiber and gellan with constant shear rates had higher shear stresses and apparent viscosities than non-pasteurized samples. Moreover, pasteurization of the Dooghs led to an increase in the consistency coefficient and a decrease in the flow behavior index as well as an increase in the plastic viscosity and yield stress. The heat-treatment of the Dooghs resulted in a more pseudo-plastic behavior. The new products were stable during storage; however, about 55% phase separation occurred in control samples. Addition of 0.4% (w/w) fiber and gellan led to an acceptable appearance, odor, taste, off-flavor, consistency and overall acceptability. [Copyright &y& Elsevier]

Doogh, an Iranian drinking yoghurt type, is a fermented dairy beverage and constitutes an important part of daily beverage consumption in Iran. Doogh is commonly produced from mixing of yoghurt, drinking water, salt and essence of aromatic vegetables such as thyme, mint and oregano. Although some undesired properties such phase separation due to the low pH and aggregation of casein may be seen frequently in doogh, the high tendency for its consumption has increased the scientific and industrial efforts in order to improve the quality of the product. The specific standards are determined for doogh by the Institute of Standard and Industrial Researches of Iran (ISIRI). The aim of this paper is to give an overview on the production and quality properties of doogh. [ABSTRACT FROM AUTHOR]

Abstract: Doogh is a traditional Iranian drink prepared by fragmentation and dilution of yogurt, with addition of salt and flavouring. In the present work, we have used viscometry, microscopy, particle-size analysis and measurements of serum separation to explore the effect of very low concentrations of gellan gum (0.01, 0.03 and 0.05wt %), alone or in combination with 0.25wt % high-methoxy pectin (HMP), on its structure and stability. HMP is known to prevent association of casein particles in acidic milk drinks by steric stabilisation, forming a protective layer bound electrostatically to the surface of the particles. Doogh incorporating 0.25wt % HMP alone showed satisfactory stability on storage for ∼10 days at 5°C, but after 15 days there was obvious separation into a dense sediment and a much clearer upper layer that occupied more than 80% of the total volume, which we attribute to progressive sedimentation of individual sterically-stabilised particles. Samples incorporating gellan (with or without HMP), by contrast, showed rapid development of a clear serum phase, with little further separation at longer times (up to ∼1 month), suggesting expression of fluid by contraction of a gel network (i.e. syneresis rather than sedimentation). Particle size increased dramatically (more than 10-fold) with increasing concentration of gellan, and at the highest concentration studied (0.05wt %) a continuous network of casein-rich strands was observed by phase-contrast microscopy. The concentration of NaCl used in the doogh samples (0.5wt %≈85mM) is known to be sufficient to maintain gellan in its ordered (double-helix) conformation, which has higher charge density than individual molecules of HMP. We suggest that network structure is formed by electrostatic attachment of gellan to fragments of acid-casein gel, thus increasing particle size and inhibiting surface-coverage by HMP, with weaker associations between gellan helices allowing the samples to flow. Observed decrease in serum volume with increasing concentration of gellan is attributed to formation of progressively stronger coupled networks with greater resistance to syneresis. Stabilisation of doogh with 0.05wt % gellan in combination with 0.25wt % HMP had no adverse effect on organoleptic acceptability, and reduced serum volume on protracted storage to ∼10% (in comparison with over 80% for the same concentration of HMP alone), suggesting that gellan could be of practical value in extending the shelf-life of doogh (and related acidic milk drinks). [Copyright &y& Elsevier]