Impact of Inulin Addition on Properties of Natural Yogurt

Abstract

The influence of the amount of inulin addition (3%, 6%, 9%, 12% or 15% w/w) on the physicochemical properties of natural yogurt was analyzed. The acidity (titration; pH), texture parameters (penetration test), viscosity curves (rotational rheometer), microrheology (macroscopic viscosity index, MVI; elasticity index, EI; solid-liquid balance—SLB; multi-speckle diffusing-wave spectroscopy, MS-DWS) and physical stability (syneresis; LUMiSizer test) of yogurts were investigated. All samples were non-Newtonian pseudoplastic liquids. The sample with 15% inulin content presented an approx. 4% higher pH value (4.34), 3-fold greater MVI and almost 5-fold higher penetration force, compared to the control sample (0% of inulin). In turn, the use of inulin addition in the range of 3–15% w/w resulted in a reduction of syneresis (p < 0.05). A linear decrease in the values of instability indexes and sedimentation velocities was noted in the function of inulin content increase (LUMiSizer test). The application of inulin (in the range of 3–15% w/w) as a functional additive to yogurts significantly contributed to enhancement of their physical stability. Summing up, the possibility of obtaining natural yogurts with a high content of this prebiotic has been demonstrated, thus such products can be classified as functional foods and a health claim can be put on the label.

Addition of inulin to probiotic yogurt: Viability of probiotic bacteria (Bifidobacterium bifidum) and sensory characteristics

“…This increase contributed to the high metabolism activity of starter cultures with increasing the inulin, which in turn, elevates the acidity development (Akın et al., 2007). However, this was not in agreement with other studies that increasing the inulin in yogurt is decreasing the acidity (Balthazar et al., 2016; Helal et al., 2018; Żbikowska et al., 2020). This can be related to the metabolism activity of starter cultures used to make yogurt.…”

“…Another study found that the overrun and glass transition of yogurt improved with the addition of 4 and 6% inulin while hardness was decreased (Muzammil et al., 2017). Furthermore, the addition of inulin at a range of 3 to 15% improved the functional characteristics with low syneresis (Żbikowska et al., 2020). Additionally, the apparent viscosity of yogurt increased with adding inulin up to 2% to yogurt (Helal et al., 2018).…”

Functional Tea-Infused Set Yoghurt Development by Evaluation of Sensory Quality and Textural Properties

“…The physical stability of yoghurts was determined with an analytical centrifuge LUMiSizer 6120-75 (L.U.M. GmbH, Berlin, Germany) by measuring the intensity of transmitted near-infrared light in suspension, and recording of light intensity profiles as a function of time and position of the sample (“fingerprints”) [ 44 , 45 ]. Stability was shown as a space- and time-related transmission profile over the sample length.…”

“…The reported values represented the average of six replicates. The data were analyzed by the delivered software (SepView 6.0; LUM, Berlin, Germany) and the instability index was calculated [ 45 ].…”

Application of Oleogel and Conventional Fats for Ultrasound-assisted Obtaining of Vegan Creams

“…Viscosity curves were described by Ostwald s mathematical model τ kγ n , where: τshear stress Pa , k -consistency index mPas , γ -shear rate s 1 , n -dimensionless flow index. Coefficients of variation of viscosity during shearing were computed 33 . Measurements were made three times for each sample.…”