Phytosterol oxidation products from coffee silverskin

Area of Science:

• Food Science and Technology
• Agricultural Byproduct Valorization
• Nutritional Chemistry

Background:

• Coffee silverskin is an abundant organic waste from coffee roasting.
• It contains valuable components like fiber, protein, and caffeine.
• Phytosterol oxidation products (POPs) can form in silverskin during roasting.

Purpose of the Study:

• To evaluate the safety and benefits of incorporating coffee silverskin into food products.
• To quantify the formation of POPs in silverskin during roasting.
• To assess the impact of silverskin consumption on dietary POP exposure.

Main Methods:

• Monitoring POP formation in three coffee varieties during roasting using Gas Chromatography-Mass Spectrometry (GC-MS).
• Quantifying caffeine, total antioxidant capacity (TEAC), and total flavonoids in silverskin.
• Analyzing potential POP intake from teas and baked goods containing silverskin.

Main Results:

• Similar qualitative POP profiles were observed across the three coffee varieties.
• Average total POPs were 0.32 g POPs/kg silverskin, with sitosterol-derived POPs being dominant.
• Silverskin contained significant levels of caffeine (1.3 g/100 g), antioxidants (11 mmol TEAC/kg), and flavonoids (1.94–8.60 mg CE/g).

Conclusions:

• Coffee silverskin can be safely utilized in value-added products such as teas, cookies, and bars.
• Incorporating silverskin into these products minimally increases dietary POP exposure.
• This valorization strategy enhances fiber and antioxidant intake while reducing organic waste.