Standardized Grape Powder for Basic and Clinical Research

Abstract

To facilitate basic, preclinical, and clinical research regarding the health benefits of grapes, a freeze-dried grape powder has been developed that blends seeded and unseeded varieties of green, red, and blue-black California table grapes in proportions representative of an entire annual crop. Using good manufacturing practice, ~500 kg has been produced from a single vintage and analyzed for content and nutritional value. Chemical standardization is carried out that includes quantitative analysis of the major polyphenols and antioxidants catechin and epicatechin; the flavonols quercetin, kaempferol, and isorhamnetin; the anthocyanidins malvidin, peonidin, and cyanidin; and the chemoprevention agent resveratrol. For human clinical trials, a placebo powder has also been developed that is similar in caloric value, color, texture, and flavor. For animal studies, a sugar-matched diet is employed as the control. The powders can be blended with food or mixed with water and consumed as a beverage. As a result, long-term animal feeding studies or clinical trials can be carried out to assess the health benefits of grapes using a stable, reproducible, and chemically and nutritionally standardized freeze-dried grape product with an appropriate placebo powder as a control.