Scientists from the University of Massachusetts, Amherst, report that the nanoemulsions remained physically stable during storage at different temperatures, as well as protecting resveratrol against UV-light isomerization and degradation.
“This study showed that nanoemulsions formed by spontaneous emulsification offer a simple way to encapsulate resveratrol as a nutraceutical ingredient by combining by-products from the wine industry, such as grape seed oil and grape skin extract,” wrote Gabriel Davidov-Pardo and David Julian McClements in Food Chemistry.
“These nanoemulsions may be useful as resveratrol delivery systems for utilisation in functional food and beverage products.”
Resveratrol, a powerful polyphenol and anti-fungal chemical, is often touted as the bioactive compound in grapes and red wine, and has particularly been associated with the so-called 'French Paradox'.
Interest in the compound exploded in 2003 when research from David Sinclair and his team from Harvard reported that resveratrol was able to increase the lifespan of yeast cells. The research, published in Nature, was greeted with international media fanfare and ignited flames of hope for an anti-ageing pill.
According to Sinclair’s findings, resveratrol could activate a gene called sirtuin1 (Sirt1 – the yeast equivalent was Sir2), which is also activated during calorie restriction in various species, including monkeys.
Other studies with only resveratrol have reported anti-cancer effects, anti-inflammatory effects, cardiovascular benefits, anti-diabetes potential, energy endurance enhancement, and protection against Alzheimer’s.
Various techniques have been developed to deliver the compound, but the new study is said to be the first published work to use low-energy homogenisation to produce resveratrol-rich nanoemulsions from grape seed oil and grape skin extract.
Davidov-Pardo and McClements produced the nanoemulsion-based delivery system using grape seed oil (digestible) and orange oil (indigestible) to encapsulate the grape seed extract, which is rich in resveratrol.
The optimum combination of orange oil and grape seed oil was found to be 1:1, which formed droplets with average diameters of about 100 nm. A 120 microgram per milliliter dose of resveratrol was the most that could be dissolved in the oil phase, they added.
“Encapsulation of resveratrol improved its chemical stability after exposure to UV-light: 88% retention in nanoemulsions compared to 50% in dimethylsulphoxide (DMSO),” they wrote.
“This study showed that resveratrol could be encapsulated within low-energy nanoemulsion-based delivery systems and protected against degradation.”
Source: Food Chemistry
15 January 2015, Volume 167, Pages 205–212, doi: 10.1016/j.foodchem.2014.06.082
“Nutraceutical delivery systems: Resveratrol encapsulation in grape seed oil nanoemulsions formed by spontaneous emulsification”
Authors: G. Davidov-Pardo, D.J. McClements