ANSWER
Flavouring in oil form in beverage formulations will lead to the ring at the neck of the bottle which is known as creaming/ringing. The oil phase (flavor oil particles) is lighter than the water phase and forms a separation between the two emulsion sections (Beristain et al., 2006; Shachman, 2004; Friberg et al., 2003).
A weighting agent such as ester gum or hydrocolloids such as gum Arabic can be used primarily in admix with other gums to reduce the creaming of less dense oil droplets in beverage drinks (Ashurst, 2016).
Source: Shachman, 2004.
References
Ashurst, P. R. (2016). Chemistry and technology of soft drinks and fruit juices (3rd ed., pp. 106-110). Chichester: John Wiley & Sons, Ltd.
Beristain, C. I., Cruz-Sosa, F., Verde-Calvo, J. R., Pedroza-Islas, R., Rodríguez-Huezo, M. E., & Lobato-Calleros, C. (2006). Applications of soluble dietary fibers in beverages. Mexican Journal of Chemical Engineering, 5(1), 81-95.
Friberg, S., Larsson, K., & Sjöblom, J. (2004). Food emulsions (4th ed., pp. 502-517). New York: Marcel Dekker, Inc.
Shachman, M. (2004). The Soft Drinks Companion: A Technical Handbook for the Beverage Industry (pp. 43-47). Boca Raton: CRC Press.
Zhao, M. M., Kong, J., Liu, L. Y., Zhao, Q. Z. (2012). Influence of xanthan and CMC mixture on the stability of sodium caseinate emulsions. Journal of Jilin University (Engineering and Technology Edition), 42(5), 1343-1348.
