Marina Heinonen, Professor (functional foods), University of Helsinki, Department of Applied Chemistry and Microbiology, P.O. Box 27, Food Chemistry, 00014 University of Helsinki, Finland
In Finland there is a long tradition in picking wild berries for both commercial and household use. Berries (ca. 40 g/day) contribute significantly to the estimated 150 mg/day intake of flavonoids in Finland. Flavonoids and other berry phenolics have been widely investigated both in national and European collaboration projects. Regarding functional food development with substantiated health claims, research on antioxidant properties, antimicrobial effects, in vivo digestion as well as animal studies and clinical human intervention studies have been undertaken. Dairy emulsions and spreads, and liposomes represent some of the food structures used in investigations on the effect of berry phenolics.
Berries are typically rich in colorful anthocyanins, but also other phenolics such as ellagitannins and proanthocyanidins are responsible for their various bioactive effects. Most anthocyanin-rich berries exhibit significant antioxidant potential in inhibiting LDL oxidation. Bilberry (Vaccinium myrtillus) and black currant (Ribes nigrum) anthocyanins contribute the most to the antioxidant effect towards both lipid and protein oxidation. In red raspberries (Rubus idaeus), ellagitannins are responsible for the antioxidant activity 1. Proanthocyanidins, especially the dimeric and trimeric forms, in lingonberries (Vaccinium vitis-idea) are amongs the most active ingredients 2. The more complex phenolics such as ellagitannins also play a key role in inhibiting the growth of pathogenic bacteria. Especially red raspberry and cloudberry (Rubus chamaemorus) rich in ellagitannins exhibited strong inhibitory effects for example towards growth of Salmonella and Staphylococcus aureus 3.
Concerning the biological actions of dietary anthocyanins in relation to heart disease - no preventive role of dietary anthocyanins towards cardiovascular health could be established in a human intervention carried out as an European collaboration (QLK1-1999-00124, Feb 2000 to Jan 2003). Neither did berry anthocyanins reduce atherosclerosis in WHHL rabbits.
In conclusion, berry phenolics are promising ingredients for functional foods intended for health benefit. However alluring, there is not yet enough scientific evidence to support a wide range of health claims regarding functional berry foods.
- Viljanen, K., Kylli, P., Kivikari, R. & Heinonen, M. 2004. Inhibition of protein and lipid oxidation in liposomes by berry phenolics. J. Agric. Food Chem., 52: 7419-7424.
- Puupponen-Pimiä, R., Nohynek, L., Scmidlin, S., Kähkönen, M., Heinonen, M., Määttä-Riihinen, K. & Oksman-Caldentey, K.-M. 2005. Berry phenolics selectively inhibit the growth of intestinal pathogens. J. Appl. Microbiol, in press
- Määttä-Riihinen, K., Kähkönen, M., Törrönen, R., & Heinonen, M. Flavan-3-ols and proanthocyanidins in berries of Vaccinium species and their antioxidant activity. J. Agric. Food Chem, in press.