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The Influence of Particle Size Distribution on Sunflower Tahini Rheology and Structure
Author(s) -
Muresan Vlad,
Danthine Sabine,
Racolta Emil,
Muste Sevastita,
Blecker Christophe
Publication year - 2014
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/jfpe.12097
Subject(s) - rheology , particle size , sunflower , chemistry , particle size distribution , mathematics , materials science , composite material , combinatorics
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 K rieger– D ougherty 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 Applications In the production of tahini in E astern E urope, 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 tahini‐derived 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.