A Comparison of Total Antioxidant Capacities of Concord, Purple, Red, and Green Grapes Using the CUPRAC Assay.

Connor Callaghan,Robert Levin,Robert Leggett

doi:10.3390/antiox2040257

Connor Callaghan, Robert Levin + Show 1 more

Open Access

https://doi.org/10.3390/antiox2040257

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Abstract

Considering how popular grapes are in terms of their antioxidant benefits, we compared concord, purple, red, and green grapes for total antioxidant capacity (TAC) and carbohydrate concentration. All grapes were acquired from commercial sources and samples of each were separated into skinned and not skinned groups. Each whole grape and the skins were individually homogenized and then separated into pulp and supernatant fractions. Each fraction was analyzed for total TAC and carbohydrates. The concord grapes and purple grapes had significantly higher TAC in the homogenates than did the red or green grapes. The concord grapes and green grapes had significantly higher TAC in the pulp than in the cytosol whereas the red and purple grapes had approximately the same amount. The majority of the TAC of the purple and red grapes was in the skin whereas the concord and green grapes had approximately the same TAC in the skin and pulp. The concord and purple grapes had the highest TAC when compared to the red and green grapes, whereas the red and green grapes had approximately the same total TAC.

Highlights

Grapes are frequently touted as excellent sources of antioxidants [1,2,3] which are molecules involved in protecting cells against oxidative stress
It is known that the polyphenols in purple and red grapes consist predominantly of anthocyanins whereas in green grapes flavanols constitute the majority of the polyphenols [9,14,15]
The carbohydrate concentration of the green grapes was significantly different from all other grapes; p < 0.05

Summary

Introduction

Grapes are frequently touted as excellent sources of antioxidants [1,2,3] which are molecules involved in protecting cells against oxidative stress. Since oxidative stress leads to cell death and has been linked to a variety of diseases ranging from cancer and heart disease to Alzheimer’s disease and anxiety disorders [4,5,6,7,8,9], it cannot be overstated how important of a role antioxidants play in the body. Due to their ability to neutralize free radicals and stabilize oxidative stress [10], antioxidants have experienced a surge in popularity. It is known that the polyphenols in purple and red grapes consist predominantly of anthocyanins whereas in green grapes flavanols constitute the majority of the polyphenols [9,14,15]

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