Pectin nanoparticles show encapsulation potential

The new study used an electrostatic deposition process, coating proteins with sugar beet pectin, to form so-called core-shell biopolymer particles.

Such particles could then be used to encapsulate, protect and deliver ingredients such as lipids, peptides, enzymes and other lipophilic materials, according to research published in the Journal of Food Science .

Stable over pH range The researchers, affiliated with the University of Massachusetts and Mahidol University in Bangkok, electrostatically deposited sugar beet pectin onto a heat-denatured beta-lactoglobulin protein.

Stable core-shell biopolymer particles were formed by mixing a suspension of protein aggregates (formed by heating the beta-lactoglobulin at 80C at pH 5.8) with the sugar beet pectin at pH 7, and then adjusting the pH to below pH6 where the pectin is adsorbed.

The particles were found to be stable over the pH range of 4 to 7, but clumped together or aggregated under more acidic conditions.

The particles did not clump together in salt concentrations less than 250 millimoles at pH4, "indicating that they had good salt stability," wrote the researchers.

Stability under differing pH levels and ionic strengths is important as these factors often vary in cosmetics, food and pharmaceutical products, they added.

Economical large scale production Furthermore, the researchers noted that the biopolymer particles could be produced economically and on a large scale as the materials and methods are not expensive.

"The biopolymer particles produced using the above-mentioned approach would be assembled entirely from food grade ingredients (proteins and dietary fibres) using simple processing operations (mixing and pH adjustment)," wrote the researchers.

Research needed into other pectins However, the researchers said that further studies should focus on analysing the fine structure of the nanoparticles.

"It should be noted that we used beet pectin in this study, which has different molecular characteristics than other types of commonly used pectins (such as apple or citrus pectin)," they added.

"Further research is therefore needed to understand how other types of pectin and anionic polysaccharides impact the formation and stability of biopolymer core-shell particles.

In particular, it would be advantageous to carry out future research using anionic polysaccharides with well-defined molecular characteristics."

Source: Journal of Food Science Published online ahead of print, doi: 10.1111/j.1750-3841.2008.00804.x "Core-Shell Biopolymer Nanoparticles Produced by Electrostatic Deposition of Beet Pectin onto Heat-Denatured -Lactoglobulin Aggregates" Authors: R. Santipanichwong, M. Suphantharika, J. Weiss, D.J. McClements