Lignin-Based Biopolymeric Active Packaging System for Oil Products

Area of Science:

• Food Science
• Materials Science
• Polymer Chemistry

Background:

• Conventional plastic packaging relies on petroleum and lacks biodegradability.
• Biopolymer-based packaging offers a sustainable alternative but often has performance limitations.
• Active packaging incorporating antioxidants can enhance food preservation.

Purpose of the Study:

• To investigate the antioxidant activity of enzymatically modified soybean protein films with alkali lignin and lignosulfonate.
• To evaluate the efficacy of these films in preventing lipid oxidation in soybean oil and fish fatty acid ethyl ester (FAEE) under direct and indirect contact conditions.
• To assess the potential of these lignin-modified films as active food packaging materials.

Main Methods:

• Soybean protein films were enzymatically modified and incorporated with alkali lignin or lignosulfonate.
• Films were tested in direct contact (in oil vials) and indirect contact (covering oil vials) systems with soybean oil and fish FAEE.
• Oxidation was assessed using peroxide value (PV), color, headspace oxygen, and volatile compound analysis.
• Direct contact tests were conducted in the dark at 40 °C; indirect contact tests under standard commercial lighting.

Main Results:

• Lignin-containing films significantly reduced peroxide values in soybean oil under direct contact conditions compared to control films.
• No significant effect of lignin was observed on oil color.
• Modified films reduced volatile compounds in both soybean oil and fish oil samples.
• Soybean protein films with lignin demonstrated greater efficacy with soybean oil than fish oil, likely due to the latter's higher initial oxidation.

Conclusions:

• Enzymatically modified soy protein films with lignin exhibit significant antioxidant activity, acting as effective radical scavengers.
• These films show potential as active packaging materials, offering protection against oxidation and UV light.
• The incorporation of lignin into biopolymer films improves their performance for food packaging applications, enhancing shelf life and product quality.