Flow behavior studies of kefir type systems

Yovanoudi, M.; Dimitreli, Georgia; Raphaelides, Stylianos N.; Antoniou, K.D.

doi:10.1016/j.jfoodeng.2013.03.036

Cited by 21 publications

(21 citation statements)

References 18 publications

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“…; Yovanoudi et al . ). Kefir is produced by lactic acid and alcohol fermentation micro‐organisms, which originally are present in the carbohydrate and protein matrix of the kefir grains and can be used as a starter (Diosma et al .…”

Section: Introductionmentioning

confidence: 97%

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Physicochemical and sensory properties of kefir containing inulin and oligofructose

Glibowski

Zielińska

2015

Int J of Dairy Tech

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This study concerns the physicochemical and sensory analysis of stirred kefirs made at a laboratory scale, in which one‐third of the skim milk powder (SMP) was replaced by different inulins (long chain, native and oligofructose). The reference kefirs contained 12 g/100 g of SMP or whole milk powder. Rheological analysis showed that the kefirs were viscoelastic materials with thixotropic and shear‐thinning behaviour. Rheological data showed that SMP can be successfully substituted by long‐chain inulin; however, sensory evaluation indicated that substitution of SMP by any other kinds of inulin significantly decreased the consistency of kefirs while not affecting their flavour and odour.

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Section: Introductionmentioning

confidence: 97%

“…Nowadays, freeze‐dried concentrated cultures that guarantee the commercial manufacture of a uniform and stable product (Bylund ; Yovanoudi et al . ) are widely used. Typical micro‐organisms present in kefir belong to lactic acid bacteria ( Lactobacillus , Lactococcus , Leuconostoc , Streptococcus spp.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical and sensory properties of kefir containing inulin and oligofructose

Glibowski

Zielińska

2015

Int J of Dairy Tech

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“…The first two properties decreased dramaticaly as temperature reduction proceed, while normal stresses remain similar as temperature dropped. Solids concentration is one of the main factors that can modify the viscosity [8]. Rheological behavior of 5% w/w samples is lower than 10% w/w samples, and the latter is also lower than 20% w/w Kefir concentration samples; which may be due to viscoelastic properties of the strongest network that might be present in 20% w/w Kefir acidic milk samples.…”

Section: Resultsmentioning

confidence: 99%

“…Techniques for measuring the rheological properties of food fluids were used for 30 years [2][3][4]; although most current efforts to measure the rheological behavior of fluids include works of Rao [5], Steffey [6] and Roudot [7]. Rheological characterization of Kefir products is important not only for the design of unit operations, but also for optimization processes and quality assurance of food products [8][9][10][11]. For instance, Yovanoudi et al [8] showed that apparent viscosity was a function of the D DAVID PUBLISHING type of starter, fermentation temperature and casein content; Dinkci et al [9] prepared a fermented drink with 20%, 40% and 60% of Kefir grains, and found that the samples made with 20% of Kefir grains were preferred in the sensorial evaluation; Wang et al [10] isolated Lactobacillus plantarum from Tibet Kefir in order to increased Kefir fermented drink flavor; and, Glibowski and Zielinska [11] found that Kefir was a viscoelastic material with thixotropic and shear-thinning behavior.…”

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confidence: 99%

Physicochemical and Rheological Characterization of an Acidic Milk Product: Kefir Concentration Effect

Delgadillo¹,

Lara²,

Santillan³

et al. 2017

JFSE

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Abstract:The main objective of this study was the analysis of physicochemical and rheological behavior of a drinkable beverage prepared with different concentrations (5%, 10% and 20% w/w) of Kefir. Several rheological models were also evaluated to determine the model that better fit experimental data. Apparent viscosity was measured with a Brookfield Viscometer within shear rates of 0.26 rad/s to 2.09 rad/s; and with an Ar-2000ex TA Instruments Rheometer within shear rates of 0.01 rad/s to 1,000 rad/s. Physicochemical tests, such as titratable acidity, chloride percent, fat concentration, color, humidity, syneresis, and total solids, were determined using laboratory equipment. The main result observed in all samples tested with Brookfield viscometer was that Kefir drink behaved as a Newtonian Fluid within shorter strain rates (0.26 rad/s to 2.09 rad/s). However, when the same samples were tested with Ar-2000ex Rheometer, a different behavior was observed: Over a wider range of shear rates, the fully non-Newtonian behavior of Kefir samples was discovered. Besides, additional variables such as shear and normal stresses, and loss and storage modulus, were analyzed with Ar-2000ex Rheometer. The rheological model that better fitted the experimental data was Cross model, followed by Power Law Model. Statistical analysis of viscosity data acquired with Brookfield Viscometer from all Kefir concentrations was not significant (p values greater than 0.05); which demonstrated that the effect of Kefir concentration over shorter strain rates was not significant, and thus, the samples behave as a Newtonian fluid. On the other hand, p values lower than 0.05 were observed in most of the different Kefir concentration samples tested with Ar-2000ex Rheometer; which indicates that a statistical significant effect was observed and thus a non-Newtonian behavior of Kefir samples. All statistical analysis was performed with SPSS v.16 software, selecting a Duncan Test with a confident interval of 95% to accept or reject the variances compared of the different Kefir concentration samples.

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“…Yapılan çalışmalar, kefirin düzenli tüketiminin insan bağışıklık sistemini güçlendirdiğini, anti-alerjik ve anti-astimatik etki gösterdiğini, kanser riskini azalttığını, kolesterolü düşürdüğünü ve diyabet ile obeziteyi engellediğini göstermektedir [2]. Sağlıkla ilgili yararlarının yanında kefirin fiziksel özellikleri de tüketici tarafından kabul edilebilirliğini etkilemektedir [3]. Üretimde kullanılan sütün bileşimi, starter kültür çeşidi, süte uygulanan ısıl işlem ile homojenizasyon işlemi, inkübasyon sıcaklık ve süresi, soğutma ve depolanma koşulları gibi pek çok faktör kefir ve yoğurt gibi fermente süt ürünlerinin fizikokimyasal özelliklerini etkilemektedir [4].…”

Section: Introductionunclassified

Sütün Homojenizasyonunun Kefirin Fizikokimyasal ve Mikrobiyolojik Özellikleri Üzerine Etkisi

Ergin¹,

Öz²,

Özmen³

et al. 2017

Akademik Gıda

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Effect of Homogenization of Milk on Physicochemical and Microbiological Properties of Kefir ABSTRACTIn this study, the physicochemical and microbiological characteristics of kefir produced from homogenized milk at four different pressures (15, 15/5, 30 and 30/5 MPa) in single-stage or two-stages were determined. Kefirs were stored at 4°C for 30 days. Dry matter, ash, fat and protein contents of samples were determined on the first day of storage while pH, titratable acidity and rheological and microbiological properties of samples were determined on the 1 st , 15 th and 30 th days of storage. Moreover, particle sizes were determined in milk homogenized at different pressures. With an increase in the homogenization pressure and stage, the D[4,3] (µm) and D[3,2] (µm) values of milk samples increased while their specific surface area values decreased. At the end of the storage period, pH, viscosity, thixotropy and consistency coefficient values, lactobacilli, lactococci, total mesophilic aerobic bacteria and yeast counts decreased in kefir samples. The highest viscosity, thixotropy and consistency coefficient values were determined in samples produced at 15 MPa in a single-stage, and the highest counts of lactobacillus, lactococcus and yeast were in samples produced with non-homogenized milk.

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Flow behavior studies of kefir type systems

Cited by 21 publications

References 18 publications

Physicochemical and sensory properties of kefir containing inulin and oligofructose

Physicochemical and sensory properties of kefir containing inulin and oligofructose

Physicochemical and Rheological Characterization of an Acidic Milk Product: Kefir Concentration Effect

Sütün Homojenizasyonunun Kefirin Fizikokimyasal ve Mikrobiyolojik Özellikleri Üzerine Etkisi

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