Design of β-Carotene Encapsulated Emulsions for Thermal Processing and Storage

This study aims at providing knowledge on the ability of food oil-in-water emulsions at sustaining extremely high temperature such that they can be used for sterilized food. Emulsions were prepared using biopolymer chitosan as Pickering emulsifier and ultrasonication for size reduction of oil droplets. Zeta potential, physical stability, and particle size distribution of emulsions were measured. The prepared emulsions were subjected to heat treatment at 121 degrees C using an aluminum cell-oil bath arrangement for varying time periods (30 and 60 min) in sealed polymeric pouches. After heat treatment, emulsions were stored for 2 weeks under accelerated storage condition of 37 degrees C and their physical stability, degradation of p-carotene, and loss of pigmentation as changes in L*, a*, and b* were analyzed to establish the stability of emulsions post-thermal stress. It was observed that the encapsulation matrix composed of self-aggregated chitosan could withstand heat processing treatment up to 1 h at 121 degrees C. The percent retention of beta-carotene varied from 82 to 45% depending on the length of exposure at 121 degrees C and perceptible change in color as Delta E greater than 2 was recoded for 30 min and 60 min treatments. During subsequent storage at 37 degrees C, the measured content of beta-carotene and color parameters remained mostly constant. These emulsions could be incorporated into sterilized food which have a long shelf life thereby extending the availability of encapsulated bioactive during storage after thermal processing.

Automated summary

This study investigates the stability of food oil-in-water emulsions at extremely high temperatures and finds that emulsions prepared using chitosan as an emulsifier can remain stable under heat treatment at 121 degrees Celsius. Additionally, the retention percentage of encapsulated beta-carotene varies depending on the exposure time at 121 degrees Celsius, but remains mostly constant during subsequent storage.