Deep eutectic solvent extraction and AB-8 resin adsorption for rambutan shell polyphenol: Profiling and bioactivity...

Area of Science:

• Agro-industrial by-product valorization
• Natural product chemistry
• Food science and technology

Background:

• Rambutan shell is a significant agro-industrial waste rich in bioactive polyphenols.
• Efficient extraction and purification methods are needed to harness these compounds.
• Polyphenols possess various health benefits, including antioxidant and anti-glycemic properties.

Purpose of the Study:

• To optimize polyphenol extraction from Baoyan NO.7 (BY-7) rambutan shell using deep eutectic solvent (DES).
• To purify the extracted polyphenols using AB-8 resin.
• To characterize the polyphenol profile and elucidate adsorption mechanisms for resource valorization.

Main Methods:

• Optimization of polyphenol extraction using DES.
• Purification of extract using AB-8 resin.
• Characterization of polyphenol profile via next-generation metabolomics (NGM).
• Evaluation of antioxidant and anti-glycemic activities.
• Adsorption mechanism study using kinetic models.

Main Results:

• Optimized extract exhibited high total phenolic, flavonoid, and proanthocyanidin content.
• Extract demonstrated significant antioxidant (DPPH, FRAP) and anti-glycemic (α-amylase, α-glucosidase inhibition) activities.
• Adsorption process followed Langmuir and pseudo-second-order models, indicating spontaneity.
• Proanthocyanidin B1 was identified in BY-7 rambutan shell for the first time.
• Significant correlations were observed between identified polyphenols and bioactivities.

Conclusions:

• Deep eutectic solvent extraction and AB-8 resin purification offer an effective method for obtaining bioactive polyphenols from rambutan shell.
• The valorization of rambutan shell provides a sustainable source of compounds with potent antioxidant and anti-glycemic properties.
• This study establishes a foundation for the industrial application of rambutan shell polyphenols.