Crude ethanolic extract from spent coffee grounds: Volatile and functional properties

Area of Science:

• Food Science
• Cosmetic Science
• Analytical Chemistry

Background:

• Increasing consumption of espresso capsules generates significant amounts of spent coffee grounds (SCG).
• SCG represent a potential source of valuable compounds if properly extracted and characterized.
• Previous research has not fully explored the volatile profile, antioxidant activity, and sun protection factor of SCG extracts.

Purpose of the Study:

• To evaluate the volatile profile (VP), antioxidant activity (AA), and sun protection factor (SPF) of a crude ethanolic extract from espresso capsule SCG.
• To determine the yield and composition of the extract.
• To assess the potential industrial applications of the SCG extract.

Main Methods:

• Extraction of SCG using ethanol to obtain a crude extract.
• Analysis of the volatile profile using gas chromatography-mass spectrometry (GC-MS).
• Quantification of antioxidant activity using DPPH assay and determination of sun protection factor (SPF).
• Chemometric analysis (Principal Component Analysis - PCA) to assess extract repeatability.

Main Results:

• Ethanol extraction yielded more unsaponifiable matter compared to ether extraction.
• The volatile profile identified 70 compounds characteristic of roasted coffee oil.
• Antioxidant activity ranged from 18.4 to 23.6 (mg extract mg DPPH^-1).
• Sun protection factor ranged from 2.27 to 2.76.
• PCA confirmed the repeatability of the extraction process.

Conclusions:

• Espresso SCG crude ethanolic extract possesses a rich volatile profile, significant antioxidant activity, and a notable sun protection factor.
• The extract demonstrates desirable properties suitable for applications in the cosmetic and food industries.
• SCG presents a sustainable and valuable resource for the development of new products.