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EMERGING RESEARCH FRONTS - 2008

Ron Wrolstad talks with ScienceWatch.com and answers a few questions about this month's Emerging Research Front in the field of Agricultural Sciences. The author has also sent along images of their work.
Wrolstad Article: Anthocyanins, phenolics, and antioxidant capacity in diverse small fruits: Vaccinium, Rubus, and Ribes
Authors: Moyer, RA;Hummer, KE;Finn, CE;Frei, B; Wrolstad, RE
Journal: J AGR FOOD CHEM, 50 (3): 519-525 JAN 30 2002
Addresses: Oregon State Univ, Dept Food Sci & Technol, 100 Wiegand Hall, Corvallis, OR 97331 USA.
Oregon State Univ, Dept Food Sci & Technol, Corvallis, OR 97331 USA.
King Coll, Bristol, TN 37620 USA.
(addresses may have been truncated.)

Why do you think your paper is highly cited?

There continues to be intense interest in the phytochemical composition and antioxidant properties of fruits and vegetables because of their possible health benefits. While there have been several surveys reporting the antioxidant properties of a wide range of fruits and vegetables, this study focused on a large sampling (107 genotypes) of Vaccinium, Rubus, and Ribes. Some key findings were a high correlation between phytochemical composition and antioxidant properties, and a wide range of total anthocyanins, total phenolics, and antioxidant properties within the three genera.

Does it describe a new discovery, methodology, or synthesis of knowledge?

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Our laboratory has a number of other publications on the phytochemcal composition and antioxidant properties of various fruits, published prior to and after this paper. The analytical methodology and experimental approach is not all that novel in this paper. I suspect that its high citation is because of the sampling. The senior author, Richard Moyer, carefully selected all samples from two sites in the Willamette Valley. He also conducted all analyses, except for the oxygen radical absorbance capacity (ORAC) and ferric reducing ability of plasma (FRAP) measurements, which were done at the Linus Pauling Institute at Oregon State University.

The wide range in total anthocyanins, total phenolics, and antioxidant properties within the three genera has strong implications for plant breeders and horticulturists. An interesting finding is that for highbush blueberries, small berry size was highly correlated with phytochemical content and antioxidant properties because of the higher proportion of skin where these compounds are concentrated.

Would you summarize the significance of your paper in layman's terms?

This paper reports the anthocyanin pigment content, total phenolics, and antioxidant properties for a large sampling (n=107) of blueberries, blackberries, red and black raspberries, and red and black currants. The phytochemical content is highly correlated with the antioxidant values. Many believe that these properties are related to the positive nutritional benefits of fruits.

The study showed a wide range of values within the different fruit varieties, suggesting that plant breeders have the potential for developing so-called "super-fruits" with high phytochemical content and antioxidant values. An interesting finding that was particularly true for blueberries was that small berry size was highly correlated with phytochemical content and antioxidant properties because of the higher proportion of skin where these compounds are concentrated. For highbush blueberries (V. corymbosum L., fruit size was inversely correlated (r = 0.84) total anthocyanins.

How did you become involved in this research and were any particular problems encountered along the way?

Our laboratory has worked on the phytochemical composition of fruits and vegetables and its impact on quality for many years. Some major issues have been the color quality of fresh and processed products, and fruit juice authenticity. We have enjoyed a long-term positive collaborative working relationship with OSU Horticulture faculty and USDA scientists. Anthocyanin pigments and polyphenolics are of particular interest, and research on their possible health benefits was initiated through cooperative projects with scientists at OSU's Linus Pauling Institute.

It was our good fortune when Richard Moyer, biochemist and Associate Professor in the Biology Department at Kings College in Bristol, TN, received sabbatical support from Kings College to work with USDA plant breeder Chad Finn, Kim Hummer of the USDA-ARS Germplasm Repository, and myself on the phytochemical composition and possible health benefits of small fruits. Richard has a keen interest in the health benefits of fruits and wanted to gain expertise in the analysis of anthocyanins and polyphenolics, and also take advantage of the plant materials available at OSU. This quality of this publication is largely due to the skill and effort of Richard Moyer.

Where do you see your research leading in the future?

As corresponding author, I retired in 2004 after 40 years service at OSU, and no longer have an active laboratory research program. However, colleagues Chad Finn, Kim Hummer, and Balz Frei are actively engaged in research at OSU, and Richard Moyer is active in teaching, outreach, and research at Kings College.

Do you foresee any social or political implications for your research?

With the assumption that human health is a social issue, then research on anthocyanin pigments and polyphenolics and their possible health benefits is important. Research on the absorption and metabolism of these compounds and their mechanism of action is a very active research area. Basic information on food composition and how it is affected by processing continues to be needed. We need to have an understanding as to why increased consumption of fruits and vegetables is related to a healthier populace.

Ronald E. Wrolstad
Distinguished Emeritus Professor
Department of Food Science & Technology
Oregon State University
Corvallis, OR, USA



2008 : April 2008 : Ron Wrolstad