Total Anthocyanin Content of Strawberry and the Profile Changes by Extraction Methods and Sample Processing.

Area of Science:

• Plant biochemistry
• Food science
• Analytical chemistry

Background:

• Anthocyanins are vital polyphenolic pigments in fruits and vegetables, impacting human and plant health.
• Quantification typically involves spectrophotometric methods, with pH differential and organic solvent-based approaches being common.
• Previous studies suggest these methods may yield different anthocyanin profiles.

Purpose of the Study:

• To identify and compare anthocyanin profiles extracted by pH differential and organic solvent-based methods from strawberries.
• To determine the total anthocyanin content extracted by various methods.
• To investigate the impact of solvent composition and pH on anthocyanin extraction efficiency and profile.

Main Methods:

• Six spectrophotometric and Ultra High Performance Liquid Chromatography (UHPLC) methods were employed.
• Methods included various combinations of organic solvents (methanol, chloroform-methanol) and pH adjustments.
• Extraction efficiency and anthocyanin profiles were analyzed using spectrophotometry and UHPLC.

Main Results:

• Acidified chloroform-methanol demonstrated the highest anthocyanin extraction efficiency compared to water-based solvents.
• Methanol-water mixtures outperformed methanol alone, suggesting complementary extraction of different anthocyanin profiles.
• UHPLC analysis revealed pelargonidin as the primary anthocyanin in higher pH (3.0) chloroform-methanol extracts, while delphinidin dominated lower pH (1.0-2.0) methanol/water extracts.

Conclusions:

• Chloroform-methanol and methanol-water solvents are optimal for extracting anthocyanins from strawberries.
• Solvent choice and pH significantly influence the extracted anthocyanin profile and content.
• Freeze-dried strawberries exhibited higher anthocyanin content than fresh or frozen samples.