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Accelerating Shelf-life Tests (ASLT) New formulations always have to be analyzed in terms of physical stability beside chemical and sensory evaluation leading to time-consuming development processes. The industry consequently employs ASLTs to accelerate these changes. In difference to beer a systematic approach to evaluate the effect of artificial storage conditions for rapid tests in emulsion based beverages is not available yet. Therefore, different tests were compared in regard to physical changes of beverages with orange oil emulsion. C) Low Homog. Pressure 12 % Emulsifier (OSA-starch) 6 % Orange oil 6 % Weighting agent HP-homogenization: 1x 250/50 bar x 90 = 5710 nm Comparative study of accelerated shelf-life tests on physical ageing of beverages containing weighted flavor emulsions Conclusion Motivation Sören Rossmann, Verena Wolff, Ulrich Müller, Jan Schneider North Rhine Westfalia Institute of Food Technology ILT.NRW, Lemgo, Germany References www.ilt-nrw.de [1] Piorkowski, D. T. and McClements, D. J. (2014): Beverage emulsions: Recent developments in formulation, production, and applications, Food Hydrocolloids, 42. [2] Tan, C.-T.: Beverage Emulsions, in Friberg, S. E. and Larsson, K. (Eds.)(1997): Food emulsions, 3. ed., rev. and expanded, Dekker, New York. [3] Reiner, S. J.; Reineccius, G. A. and Peppard, T. L. (2010): A Comparison of the Stability of Beverage Cloud Emulsions Formulated with Different Gum Acacia- and Starch- Based Emulsifiers, Journal of Food Science, 75,5. [4] Lim, S. S.; Baik, M. Y.; Decker, E. A.; Henson, L.; Michael Popplewell, L.; McClements, D. J. (2011): Stabilization of orange oil-in-water emulsions: A new role for ester gum as an Ostwald ripening inhibitor, Food Chemistry, 128,4. Results Contact ILT.NRW Beverage Technology Sören Rossmann [email protected] Emulsion based beverages Beverage emulsions are an important product for the preparation of increasingly popular beer-based mixed drinks and soft drinks in order to incorporate water insoluble colors or flavors (flavor emulsion), to generate turbidity (cloud emulsion) or both combined [1]. Compared to other oil-in-water food emulsions, beverage emulsions are a unique class of type, as they are highly concentrated semi-finished products and after being processed in- to drinks finally consumed considerably diluted [2]. Experimental Setup A) Reference Emulsion 12 % Emulsifier (OSA-starch) 6 % Orange oil 6 % Weighting agent HP-homogenization: 2x 300/50 bar B) Reduced Ester Gum 12 % Emulsifier (OSA-starch) 10 % Orange oil 2 % Weighting Agent HP-homogenization: 2x 300/50 bar x 90 = 736 nm x 90 = 620 nm D) Reduced Emulsifier 6 % Emulsifier (OSA-starch) 6 % Orange oil 6 % Weighting agent HP-homogenization: 2x 300/50 bar x 90 = 785 nm Emulsions A to D were diluted to Ready-to-drink beverages for stability analyzing: 0,12 % emulsion diluted with beverage base (10 °Bx sucrose, pH 3,2) Instability indices showing the deterioration of the beverages containing emulsions A to D (different produĐt defeĐtsͿ over a storage period of 50 days (accelerated) and 180 days (real-time storage), respectively. To compare the efficiency of the ASLTs, exponential functions were fitted to the measured values, which allow calculation of the accelerating factors of the ASLTs against the real-time storage. Particle size distribution of the beverages with the four emulsions A to D directly after preparation (left) and after storage under accelerating conditions (right). 50 days storage under accelerating storage conditions: (Comparative real-time storage: 180 d at 20 °C) Before storage After storage EnhanĐing physiĐal instaďilities ďy integrating artifiĐial „produĐt defeĐts“: Agitation 20 °C, 120 min -1 Light box 40 °C, 5000 Lx Thermostat cabinet, 40 °C Instability- mechanism [1,4] A) Reference emulsion 8.2 9.1 7.9 (Diffusion) B) Reduced Ester Gum 7.7 5.8 6.5 Ostwald Ripening C) Low Homog. Pressure 11.0 9.1 9.6 Creaming D) Reduced Emulsifier 9.2 8.7 7.9 (Diffusion) The examined ASLTs are capable of accelerating the physical deterioration of emulsion- based beverages remarkably. Accelerating factors of 5.8 up to 11.0 were achieved regardless of the predominant instability mechanism. Surprisingly, the periodic agitation without elevated temperatures reveal the highest acceleration. Unfortunately, agitation exhibits large deviations in the resulting extent of instability compared to real-time storage. Considering all intrinsic deficiencies of the emulsion beverages, the warm storage with additional illuminance shows the deterioration most similar to the real-time storage. Since the differences in time are not extreme this test condition reveals as most promising. It is thus obvious that the results cannot be easily transferred to other emulsion formula- tions. Nevertheless, for practical purposes the results of the presented work can serve as a basis for the development and assessment of accelerated shelf-life tests. Lab-shaker Light box: 5000 Lx, 40 °C Thermostat cabinet: 40 °C 12 h·d -1 at120 min -1 6500 K daylight lamps dark Physical stability was analyzed with: - Turbidity measurement (Optek): direct analyzing of scattered light in the bottle - Particle size measurement (Malvern): laser diffraction - Calculation of instability index: InstaďilitLJ indedž = 1 − turďiditLJ τ;tͿ initial turbidiy τ 0 Physical stability problems Despite the use of stabilizing ingredients and in- tensive mechanical forces like high-pressure homogenization, physical instability phenomena are a great issue: CreaŵiŶg ;RiŶgiŶgͿ Turbidity Loss Sedimentation Inhomogeneity The reason is the inherent instability of beverage emulsions as generally known from macroemul- sions. In addition, governmental regulations restrict the application of stabilizers. Visible ringing of an orange soft drink Reference Emulsion Reduced Ester Gum Low Homogenization Pressure Reduced Emulsifier Storage time [d] Storage time [d] Storage time [d] Storage time [d] Instability index [-] Instability index [-] Instability index [-] Instability index [-] dark agitation Accelerating factors of the ASLTs Acknowledgements: This work was funded under the program FHprofUnt (FKZ: 03FH037PX3) by the Federal Ministry of Education and Research (BMBF) of the German Government.
