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.