Temperature-Driven Maillard Conjugation and Phenolic Changes in Dried Lychee Pulp: Implications for Antioxidative...

Area of Science:

• Food Science and Technology
• Nutritional Biochemistry
• Agricultural Chemistry

Background:

• Thermal aging modifies fruit ingredients through physicochemical changes.
• Lychee pulp is a rich source of bioactive compounds.

Purpose of the Study:

• To investigate the impact of thermal aging on dried lychee pulp's physicochemical, antioxidant, and Maillard conjugation properties.
• To determine the optimal temperature range for thermal aging to enhance functional qualities.

Main Methods:

• Dried lychee pulp was aged at 50, 60, 70, and 80°C for 20 days.
• Analyses included total phenolic content (TPC), total flavonoid content (TFC), phenolic profiles, saccharides, amino acids, degree of glycation (DG), peptide molecular weight, and antioxidant activity (ABTS, DPPH, FRAP).
• Principal Component Analysis (PCA) was used to correlate compositional changes with antioxidant responses.

Main Results:

• Moderate aging temperatures (60-70°C) significantly increased TPC, TFC, antioxidant activity, and DG, peaking at 70°C (DG ~47%).
• Aging at 80°C caused degradation of phenolics, sugars, and amino acids, reducing antioxidant activity.
• PCA confirmed strong links between compositional shifts and antioxidant capacity.

Conclusions:

• A temperature-dependent balance exists between Maillard conjugation and thermal degradation in lychee pulp.
• Optimal thermal aging for enhancing dried lychee pulp functionality is between 60-70°C.
• Controlled thermal aging offers potential for developing value-added functional food ingredients from fruit sources.