Food & Function Blog

In human supplementation studies nuts have been shown to improve the lipid profile, increase endothelial function and reduce inflammation, all without causing weight gain.  They have a favourable fatty acid profile with low saturated fats and high PUFA which provides a rationale for the some of these effects, however, the benefits seen in these trials are greater than what would be predicted based on the amount and nature of fat consumed.  This suggests other bioactive constituents are present – but what are they?

Joe Vinson and Yuxing Cai have tested the hypothesis that the mystery bioactive compounds are polyphenols.  This hypothesis is supported by a body of work showing nuts have antioxidant capacity.

The team from the University of Scranton in the USA measured polyphenol levels in nuts and found that walnuts had the highest free and total polyphenols.  Furthermore, total polyphenols in the nuts was significantly higher than free polyphenols and roasting had little effect on the polyphenol levels.  The team also investigated the efficacy of nut antioxidants and showed that walnut extracts were superior in binding lower density lipoprotein and inhibiting its oxidation than other nuts.  However, all nuts are high in polyphenol antioxidants which by binding to lipoproteins inhibit oxidative processes that lead to atheroscelrosis in vivo.

Finally, the team then used their findings on polyphenol levels in nuts and per capita consumption data to calculate the contribution of nuts to the daily antioxidant intake in the US diet.  They show that nuts represent 19% of the food and beverage polyphenols in the average US diet.

Interested in knowing more?  Read the full article for free until the end of January 2012.

Nuts, especially walnuts, have both antioxidant quantity and efficacy and exhibit significant potential health benefits
Joe A. Vinson and Yuxing Cai
Food Funct., 2012, Advance Article, DOI: 10.1039/C2FO10152A

Scientists from Canada have investigated b-carotene release from lipid nanodispersions under simulated gastrointestinal conditions. Enhancing the health benefits of food by incorporating bioactive molecules (such as b-carotene) is of increasing interest as it may help with chronic conditions. The bioactives can be incorporated into the food matrices by designing oil-in-water emulsions.

In this work, the influence of interfacial structure of solid lipid nanoparticle dispersions and oil-in-water emulsions containing encapsulated b-carotene  were examined under simulated gastrointestinal conditions. It was found that the uptake of lipolytic products and lipophilic bioactives depended on nonionic surfactant type, the extent of lipid digestion, as well as the presence of bile salts and phospholipids.

This work was presented at the Delivery of Functionality in Complex Food Systems Symposium held in Guelph in August 2011, and is part of our themed issue on the Delivery of Functionality coming soon in 2012. The article is free to access until the end of 2011, to read it in full click the link below:

Digestibility and b-carotene release from lipid nanodispersions depend on dispersed phase crystallinity and interfacial properties, Amir Malaki Nik, Sarah Langmaid and Amanda J. Wright, Food Funct., 2012, DOI: 10.1039/c1fo10201j

Scientists in Germany have investigated the effects of encapsulating polyphenolic grape seed extract in liposomes. Grape seed extract contains polyphenols which can reduce the extent of oxidative processes in organisms, and hence may be a beneficial food for chronic diseases such as cancer, diabetes mellitus and cardiovascular disease.

Phenolic compounds are, however, difficult to incorporate into food systems because they can strongly interact with other compounds and cause aggregation. By encapsulating the polyphenols they are protected and this may prevent them from being degraded during digestion, thereby enhancing their bioactivity and bioavailability.

In this work, coated liposomes containing grape seed extract were prepared by using chitosan and citrus pectin polymers.  The amount of polyphenols that reacted in the antioxidant test was decreased, suggesting that the polyphenols were no longer exposed to the aqueous phase. This indicates that polymer coated liposomes are highly capable carrier systems for polyphenol compounds.

This work was presented at the Delivery of Functionality in Complex Food Systems Symposium held in Guelph in August 2011, and is part of our themed issue on the Delivery of Functionality coming soon in 2012. To read the full article for free, please follow the link below:

Encapsulation of polyphenolic grape seed extract in polymer-coated liposomes, Monika Gibis, Effie Vogt and Jochen Weiss, Food Funct., 2012, DOI: 10.1039/c1fo10181a

Other articles from this conference have recently been published as Advance Articles in Food & Function. Click the following links to read Potential biological fate of ingested nanoemulsions: influence of particle characteristics and Fibrillar structures in food