Characterization of Ultrasonically Prepared Flaxseed oil Enriched Beverage/Carrot Juice Emulsions and Process-Induced Changes to the Functional Properties of Carrot Juice

Abstract

This study reports on the formation of stable emulsion of flaxseed oil (1 % v/v) in carrot juice (CJFO) using 20-kHz ultrasound (US) at 176 W and 4 min of processing time. The shear forces generated by acoustic cavitation are responsible for the production of emulsion droplets of size 0.6 μm. Pectin acted as an emulsifier providing stability by creating electrostatic repulsion (ζ potential −30 mV) between emulsion droplets and the emulsions were stable up to 8 days at 4 ± 2 °C. The viscosity of the emulsion remained unchanged with sonication time (up to 8 min) and upon storage. The unaffected flow behavior of emulsions was an advantage to adapt it to existing pipelines in food industries. Sonication led to an increase in carotenoid content to about 1.5 mg/100 ml of juice. In addition, an increase in lipid oxidation of emulsion was observed due to prooxidant characteristics of carotenoid. However, industrially, it can be prevented by adding antioxidants or by providing inert gas blanket to the process cell. In total, the formation of stable emulsions without addition of external emulsifiers and stabilizers, by using US process, is perceived a positive step towards new product/process development.