ORIGINAL PAPER Determination of Rheological Behavior, Emulsion Stability, Color, and Sensory of Sesame Pastes (Tahin) Blended with Pine Honey Mehmet Akbulut & Cemalettin Saricoban & M. Musa Ozcan Received: 9 August 2010 / Accepted: 3 August 2011 / Published online: 16 August 2011 # Springer Science+Business Media, LLC 2011 Abstract In this research, rheological properties of blends of pine honey (3%, 6%, and 9%) with sesame pastes (tahin) produced from hulled roasted sesame seeds, called simply tahin, and from unhulled roasted sesame seeds, so-called Bozkir tahin, were determined at temperatures ranging from 10°C to 60°C and at speeds ranging from 0.5 to 100 rpm. Tahin and Bozkir tahin blends with pine honey were found to exhibit non-Newtonian, pseudoplastic behavior at all temper- atures. Apparent viscosities versus speed data were success- fully fitted to the power law model. The flow behavior index, n, varied in the range of 0.4226–0.6228 for the tahin–pine honey blends, and in the range of 0.4661 to −0.7266 for the Bozkir tahin–pine honey blends. The consistency index, K, was in the range of 9.34–36.42 Pa·s n for tahin–honey blends, and in the range of 9.92–37.53 Pa·s n for Bozkir tahin–honey blends. The consistency index (K) increased with increasing honey levels in both tahin types. According to statistical analysis, the exponential model was a better model to describe the effect of the soluble solids on the viscosity of tahin samples represented by the pine honey percentage. The emulsion stability of both tahin types improved with the addition of pine honey. It was also correlated with activation energy (E a ), Arrhenius constant, some sensory properties such as spreadibility, firmness and overall acceptance, and color parameters such as the C and h. Temperature sensitivity of the consistency index was assessed by applying an Arrhenius type equation, and E a value appeared in the range of 7.61–10.05 kJ/mol for tahin–honey blends and in the range of 9.02–10.50 kJ/mol for Bozkir tahin–honey blends. Keywords Tahin . Bozkir tahin . Pine honey . Rheology . Emulsion stability . Sensory properties Introduction One of the traditional foods in the Middle East and Turkey is tahin, which is produced by grinding the hulled roasted sesame seeds. Hulled sesame seeds (without hull) are commonly used for tahin production, but it is also produced by using roasted unhulled sesame seeds (with hull) in order to produce sesame paste, and this product is known as Bozkir tahin in Turkey. There are two types of tahin, light and dark, and the light ivory version is considered to have both the best flavor and texture. Tahin is used in the preparation of some local dishes such as java beans, chickpeas, salad, and in desserts such as honey and fruit molasses (Akbulut 2008; Akbulut and Coklar 2008). Chemically, honey comprises sugars (80–85%), water (15–20%), and other minor constituents such as minerals, proteins, phenolic compounds (Akbulut et al. 2009), organic acids, and free amino acids (Sato and Miyata 2000). Pine honey also has a significant antioxidant activity due to the high amounts of phenolic substances that are included (Akbulut et al. 2009). There are many food products in the form of an emulsion, such as tahin/pekmez blends (Alpaslan and Hayta 2002) and salad dressings, sauces, and beverages (Weiss et al. 1996). The most common emulsions in foods are oil-in-water and water-in-oil types (Dickinson 1992; McClements 1999). Blends of pine honey and sesame pastes can be considered M. Akbulut (*) : C. Saricoban : M. M. Ozcan Department of Food Engineering, Agriculture Faculty, Selcuk University, 42049 Konya, Turkey e-mail: makbulut@selcuk.edu.tr Food Bioprocess Technol (2012) 5:1832–1839 DOI 10.1007/s11947-011-0668-6