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Impact of Accelerated Shelf-life Tests on Physical Stability of Beverages Based on Weighted Orange Oil Emulsions
Rossmann, S., Wolff, V., Mller, U. and Schneider, J.

Emulsions play an important role as concentrated semi-finished products for the preparation of soft drinks and also other beverages such as beer-based mixed drinks (shandies) and liquors. The determination of the physical stability of the finished product is of great interest in the development of new beverage emulsions. For practical purposes, it is barely possible to examine the beverages along the expected shelf-life in real time. Accelerated storage tests are therefore widely used in the beverage and flavor industry to obtain information on visual instability phenomena like turbidity loss, creaming (?ringing?) or sedimentation. However, a systematic approach to evaluate the instabilities enhancing storage conditions and a standard procedure is missing. In this study different storage conditions (extrinsic factors) were compared with regard to their impact on the physical changes of emulsion-based beverages: elevated temperature (40??C) with and without light exposition (40??C, 5000 Lx) and periodic agitation (12?h/d). To induce the instability phenomena within a fraction of an assumed shelf-life of 6 months, artificial product defects (intrinsic factors) were incorporated into a standard formulation of a weighted orange oil beverage emulsion: reduction of the emulsifier concentration (?50?%), reduction of the weighting agent concentration (?66?%) and weakening of the homogenization process. The results reveal that due to instabilities of the emulsions all accelerating storage conditions have remarkable but different effects on the rate and extent of deterioration. Elevated temperature storage as well as a light box accelerate physical deterioration of beverage emulsions by a factor of 5.8 to 9.6 resulting in a similar loss of turbidity in just a fraction of the normal shelf-life. Periodic agitation speeds up deterioration even faster (accelerating factor 7.7?11.0), but with greater deviations in the extent of deterioration to real-time tests and consequently a complication of a prediction.

Descriptors: beverage emulsion, turbidity, colloidal stability, accelerated shelf-life tests, forced ageing

BrewingScience, 70 (January/February 2017), pp. 31-38