Total Phenolic Content of Red and White Grape Juice
Determining Total Phenolic Content of Grape Juice using Visible Spectrophotometry
Formal Food Analysis Laboratory Report
February 7, 2013
By Carla Reed
Lab partner: Nina Jung
Total Phenolic Content of Grape Juice using Visible Spectrophotometry
Abstract
The health benefits of red wine are well known and consumption has been encouraged more over the years because of the populations increasing obesity rates and the inherent complications thereof; including coronary heart disease and high blood pressure. Since the phenolic compounds in wine combats these negative effects and originate from the grape itself the focus of this study was the total phenolic content in red and white grape juice; measured in gallic acid equivalents (GAE). This entire lab class found 105mg GAE per 100 milliliters of phenolic compounds in white grape juice and 226 mg GAE per 100 milliliters in red grape juice. The variance in the values is to be expected since different components of the grape are retained or discarded during white grape and red grape processing procedures.
Introduction
The data base of nutritional information has grown exponentially in the last decade and with it the population’s knowledge of what a beneficial diet encompasses. It is a well researched topic that heart disease is linked to the excessive consumption of dietary fat and cholesterol. Hectic lifestyles and the abundance of convenient high fat foods are contributing to health issues facing Americans today including complications due to obesity. A study preformed in the early 1990’s found that in some regions of France, despite their higher intake levels of saturated fat, the incidence of coronary heart disease remains low1. Frankel’s study correlated moderate red wine consumption with lower occurrences of coronary heart disease1. More specifically, he attributed the inhibition of oxidizing human low density lipoproteins (LDL) to the phenolic compounds and antioxidant properties found in red wine1.
Formal Food Analysis Laboratory Report
February 7, 2013
By Carla Reed
Lab partner: Nina Jung
Total Phenolic Content of Grape Juice using Visible Spectrophotometry
Abstract
The health benefits of red wine are well known and consumption has been encouraged more over the years because of the populations increasing obesity rates and the inherent complications thereof; including coronary heart disease and high blood pressure. Since the phenolic compounds in wine combats these negative effects and originate from the grape itself the focus of this study was the total phenolic content in red and white grape juice; measured in gallic acid equivalents (GAE). This entire lab class found 105mg GAE per 100 milliliters of phenolic compounds in white grape juice and 226 mg GAE per 100 milliliters in red grape juice. The variance in the values is to be expected since different components of the grape are retained or discarded during white grape and red grape processing procedures.
Introduction
The data base of nutritional information has grown exponentially in the last decade and with it the population’s knowledge of what a beneficial diet encompasses. It is a well researched topic that heart disease is linked to the excessive consumption of dietary fat and cholesterol. Hectic lifestyles and the abundance of convenient high fat foods are contributing to health issues facing Americans today including complications due to obesity. A study preformed in the early 1990’s found that in some regions of France, despite their higher intake levels of saturated fat, the incidence of coronary heart disease remains low1. Frankel’s study correlated moderate red wine consumption with lower occurrences of coronary heart disease1. More specifically, he attributed the inhibition of oxidizing human low density lipoproteins (LDL) to the phenolic compounds and antioxidant properties found in red wine1.