The Influence of Particle Size Distribution on Sunflower Tahini Rheology and Structure

Abstract

Different particle size sunflower tahini prototypes were obtained by controlling the milling process of roasted sunflower kernels. Not only the physicochemical properties of these samples but also of an industrial reference were compared and discussed in order to understand tahini behavior and structure. Granulometry was determined by a laser-scattering analyzer and revealed for all studied samples, trimodal particle size distributions. Histogram modes, as well as cumulative volume percentages (CVPs) of small-and middle-class populations, increased with the number of passes through colloidal mill, while for large particle size population, both the modes and CVPs decreased. Pseudoplastic behavior was observed for all sunflower tahini prototypes and reference, irrespective of studied temperature and particle size. However, the value of consistency coefficient ranged from 3,049 to 6.6 Pa·s n being strong dependent on particle size and temperature while flow behavior indexes between 0.53 and 0.87. Time-dependent rheological analysis revealed higher thixotropic degree of coarser sunflower tahini samples. Studied samples had rheological properties characteristic for a viscoelastic material, the response in the dynamic frequency sweep being typical for weak gels. The finest sunflower tahini prototype showed the lowest Krieger-Dougherty estimated volume fraction (0.48), while the coarsest sample the highest (0.69), sunflower tahini reference being placed in a median position with a volume fraction of 0.56. By combining all those data, a schematic structure of sunflower tahini was proposed for the first time. PRACTICAL APPLICATIONSIn the production of tahini in Eastern Europe, sesame seeds have been totally replaced by sunflower seeds due to the high availability of sunflower in this region and the comparable taste of the final product. The fundamental understanding of structure and rheology is an essential step in analyzing tahini behavior during processing and storage or when included in new food formulations. The tahini model structure proposed for the first time in this manuscript is an essential tool for food engineers when improving the stability and texture of tahini or related products (e.g., halva, hummus) as well as when designing new tahini formulations. The obtained results will contribute to quality improvements of tahiniderived products as well as to a superior valorization of sunflower kernels by replacing sesame seeds in tahini production, being of interest also for similar products such as sesame tahini, peanut butter or hazelnut paste. bs_bs_banner Journal of Food Process Engineering

Roasted Sunflower Kernel Paste (Tahini) Stability: Storage Conditions and Particle Size Influence

“…The mill is a versatile fine-grinding and dispersing system, working on the rotor-stator principle. As described by Muresan et al [33], by increasing the number of passes through the colloidal mill, eight prototypes were obtained, ranging from the coarsest sample (TH1, one pass through the colloidal mill) to the finest sample (TH8, eight passes through the colloidal mill). Tahini prototypes were obtained by a different technology than the one currently used by the food industry, but the study allowed assessing the stability of different sizes of sunflower tahini, thus providing future alternatives for the industry.…”

“…Consequently, from a practical point of view, controlling the milling stage of sunflower kernels might be an important and "in place tool" for food researchers and technologists to improve sunflower tahini stability, without adding hydrogenated fats or chemical antioxidants or emulsifiers. The current article is an essential continuation of this previously published work [33] in order to assess the colloidal and oxidative stability of the same, varied-particle-size sunflower tahini sample set. Moreover, in addition to the extensive storage test, for the first time, a rapid rheological method was used for the prediction of sunflower tahini CS.…”

“…Thus, the objective of this study was to assess the influence of the particle size distribution and storage conditions on sunflower tahini colloidal and oxidative stability. It has already been demonstrated [33] that utilizing different milling strategies in order to prepare different particle sizes of sunflower tahini, but starting from the same raw material, with the same chemical composition, leads to prototypes with very different rheological properties (e.g., prototypes that were highly viscous and thixotropic with high volume fractions to slightly viscous and thixotropic with low volume fractions, the industrial reference being intermediate). Consequently, from a practical point of view, controlling the milling stage of sunflower kernels might be an important and "in place tool" for food researchers and technologists to improve sunflower tahini stability, without adding hydrogenated fats or chemical antioxidants or emulsifiers.…”

“…Our group recently showed that sunflower tahini particle size had an impact on the product's rheological behavior and structure [33]. Thus, the objective of this study was to assess the influence of the particle size distribution and storage conditions on sunflower tahini colloidal and oxidative stability.…”

Particle Size Analysis by wet Laser Diffraction for anhydrous food suspensions: Application to sunflower tahini

“…Sunflower tahini samples were produced according to Mureşan et al (2014) by controlling the roasted sunflower kernel milling. One representative sunflower tahini (RST) sample characterized by a broad particle size distribution and coarse appearance was obtained by a single pass through the mill, while the fine sunflower tahini (FST) sample was obtained by eight passes through the colloidal mill (Microcut MCV 12B, Stephan Machinery GmbH, Hameln, Germany).…”