Writing in Food Chemistry, the research team from thee Indian institutions point out that among the various techniques used for fish oil microencapsulation, the cheapest one is spray-drying, with costs 30 to 50 times less than freeze-drying.
However, the high operational temperature coupled with the mechanical shearing during atomisation is a major challenge in the encapsulation process, because these forces may destabilise the emulsion, lead to capsule collapse as cause the oxidation of fish oil during the drying process.
“Consequently, use of cross-linking agents very often becomes necessary…Presently, formaldehyde, glutaraldehyde as well as the enzyme transglutaminase have been employed as protein cross-linking agents. However, owing to the adverse health and environmental effects associated with aldehydes, and the low economic viability of enzyme mediated processes, the demand for natural and economically sustainable alternatives is high,” they wrote.
“Hence, incorporation of natural cross-linkers and antioxidants in the emulsion may be highly advisable, especially when spray drying is involved.”
The researchers therefore wanted to assess if protein-based microcapsules, which are not usually suitable for controlled-release supplements because they are water-soluble, could be cross-linked into stable forms using sage and gum arabic, opening up the possibility of creating a supplement for omega-3 and protein simultaneously.
They stated the efficacy of herbal extracts on the structural stabilisation of fish oil encapsulation had not previously been evaluated.
“The objective of the present study was to evaluate the efficacy of sage extract and gum arabic on structural and oxidative stabilisation of fish oil encapsulates with emphasise on minimising the adverse effect of elevated temperature and mechanical shearing during spray drying,” they noted.
“Apart from that, the oxidative stability of the encapsulates during accelerated oxidative atmosphere and oil release pattern in buffered saline and gastrointestinal environment was evaluated,” wrote the researchers from the Central Institute of Fisheries Technology, the Indian Institute of Natural Resins and Gums and theMumbai Research Centre of CIFT.
High efficiency
The study found that the fish oil encapsulates stabilised with gum arabic and sage extract exhibited significantly higher encapsulation efficiency compared to encapsulates containing gum arabic alone.
“Higher encapsulation efficiency and lower surface oil content in the encapsulated products was achieved by incorporating sage extract at 1% level in the emulsion prior to spray drying,” they wrote.
“The extent of protection offered by the sage extract against fat oxidation and stability in normal food environment was significant. Hence, current findings shows that the incorporation of sage extract in fish oil before spray drying may be advocated,” they concluded.
They added that scanning electron microscopic and atomic force microscopic images revealed uniform encapsulates with good sphericity and smooth surface – indicating their suitability for commercial use.
However, they said more research was now need to understand the complete pattern of fish oil release at targeted sites of the gastrointestinal tract.
Source: Food Chemistry
Published online ahead of print: http://dx.doi.org/10.1016/j.foodchem.2016.09.126
“Structural and oxidative stabilization of spray dried fish oil microencapsulates with gum arabic and sage polyphenols: Characterization and release kinetics.”
Authors: P.K Binsai, et al.