Apple juice inhibits human low density lipoprotein oxidation

Area of Science:

• Food Science
• Nutritional Biochemistry
• Analytical Chemistry

Background:

• Dietary phenolic compounds from fruits and vegetables possess antioxidant properties beneficial for human health.
• Apples and apple juices are significant sources of these phenolic compounds.
• Understanding the phenolic composition and antioxidant capacity is crucial for dietary recommendations.

Purpose of the Study:

• To determine the phenolic composition of commercial apple juices and fresh Red Delicious apple extracts.
• To assess the in vitro antioxidant activity of apple juices and extracts in protecting low-density lipoprotein (LDL) from oxidation.
• To investigate potential correlations between specific phenolic compounds and antioxidant activity.

Main Methods:

• High-performance liquid chromatography (HPLC) for phenolic compound identification and quantification.
• Folin-Ciocalteau method for total phenol determination.
• In vitro copper-catalyzed LDL oxidation assay, measuring hexanal production via gas chromatography.

Main Results:

• Phenolic profiles varied significantly between apple juices and fresh apple extracts.
• Both apple juices and fresh apple extracts demonstrated inhibition of LDL oxidation.
• No significant correlation was found between total phenolic concentration or specific phenolic classes and antioxidant activity.

Conclusions:

• Both fresh apples and commercial apple juices possess in vitro antioxidant activity against LDL oxidation.
• The specific phenolic compounds responsible for the observed antioxidant activity require further identification.
• The findings support the inclusion of apples and apple juice in a healthy diet due to their antioxidant properties.