Metabolomic profiling of purple corn pericarp phytochemicals and their efficient recovery in deep eutectic solvents with ultrasound-assisted extraction

What if the waste from corn processing held a treasure trove of health-boosting compounds? Purple corn pericarp, a lowly byproduct, just proved it can yield a rainbow of polyphenols in just 10 minutes using eco-friendly solvents.

The hunt for green chemistry is on, and this study delivers a knockout punch. Researchers turned to purple corn pericarp, a cellulosic waste from the corn industry, known to be exceptionally rich in polyphenolic compounds. They crafted 19 different deep eutectic solvents (DESs)—a new generation of renewable, non-toxic, and biodegradable liquids—to unlock this potential.

Using ultrasound-assisted extraction, the team found that these solvents form strong intermolecular bonds, as shown by FTIR analysis, which revealed dominant O–H and C–H stretching. Metabolomic profiling via UHPLC-MS identified 36 distinct polyphenolic compounds in the pericarp. The magic happened with DES 13, a 2:1 mix of glycerol and lactic acid, which extracted 27.41 mg of anthocyanins, 240.37 mg of condensed tannins, and 25.52 mg of flavonoids per gram of pericarp in just 10 minutes.

The extracts weren't just plentiful—they were potent. They retained significant antioxidant activity, confirmed by DPPH, ABTS, and CUPRAC assays. Key players included cyanidin-3-glucoside, delphinidin, and cyanidin chloride among anthocyanins, plus caffeic acid and ferulic acid as major phenolic acids. Notably, solvent choice influenced which polyphenols were extracted, a pattern validated by principal component analysis. This green, efficient method could transform waste into wellness.

Key Points

• 19 DES formulations extracted polyphenols from purple corn pericarp
• 36 polyphenolic compounds identified via UHPLC-MS metabolomic profiling
• DES 13 yielded 27.41 mg anthocyanins/g in 10 minutes