Shielding Your Snacks: The Crucial Role of UV-Blocking Food Packaging

Importance of the Topic

An effective food packaging must protect perishable products from ultraviolet (UV) radiation that accelerates quality loss through photo-oxidation and other light-induced reactions. Simultaneously, many applications require visible transparency for consumer appeal and product inspection. Accurate measurement of UV-visible light transmission through packaging materials is therefore critical for quality control and product development in the food industry.

Study Objectives and Overview

This application note demonstrates the use of an Agilent Cary 60 UV-Vis spectrophotometer equipped with an internal diffuse reflectance accessory (DRA) to measure total transmission (diffuse plus specular) of light (200–900 nm) through various plastic food packaging samples. Key goals include:

• Assessing UV blocking performance in the 200–400 nm range.
• Quantifying visible light transmission (400–900 nm) for aesthetic evaluation.
• Demonstrating repeatability and accuracy for QA/QC workflows.

Methodology

Samples (4 × 4 cm) were cut from five packaging types: candied ginger packet, rice package, gummy bear wrapper, sesame seed bar wrapper, milk bottle, and water bottle. Each was cleaned, mounted in the DRA sample holder (6 mm aperture), and measured in total transmission mode. A 100 % transmittance baseline was acquired without a sample. Spectra were collected from 200 to 900 nm with 1 nm intervals and 0.1 s averaging. Five repeat measurements per sample were performed, rotating and repositioning each to capture surface inhomogeneity.

Instrumentation Used

• Agilent Cary 60 UV-Vis spectrophotometer
• Internal Cary 60 UV-Vis diffuse reflectance accessory (integrating sphere)
• Agilent Cary WinUV software for spectral acquisition

Main Results and Discussion

All packaging showed strong visible transparency (>70 %T) and effective blocking of UVB (280–315 nm). Specific observations:

• Candied ginger and rice packages: Mean UV transmittance ~37 % (200–400 nm), visible ~89–91 %; sharp absorption edge at 330 nm.
• Gummy bear and sesame wrappers: Mean UV ~50 %, visible ~92 %; absorption edge at 305 nm.
• Milk bottle: Reduced visible transparency (~71 %), UV semi-transmission ~38 %.
• Water bottle: UV transmittance ~29 %, visible ~89 %.

Average standard deviations across repeats were below 0.6 %T, confirming high measurement precision.

Benefits and Practical Applications

• Rapid, reliable screening of packaging UV and visible light properties.
• Improved quality control workflows for food safety and shelf-life optimization.
• Support for product development by correlating material composition with optical performance.

Future Trends and Potential Applications

Emerging material innovations such as bio-based polymers and nanocomposite coatings may offer tailored UV blocking combined with enhanced mechanical properties. Integration of inline UV-Vis measurement systems could enable real-time quality monitoring on production lines. Further development of portable spectrophotometers with diffuse reflectance capabilities will support on-site testing in manufacturing and regulatory inspections.

Conclusion

The Agilent Cary 60 UV-Vis spectrophotometer with internal DRA provides a robust, easy-to-use solution for total transmission measurements of food packaging materials. High precision and fast workflows allow food producers and packaging developers to ensure products meet both UV protection and aesthetic requirements, enhancing shelf life and consumer appeal.

References

1. Roy, S.; Ramakrishnan, R.; Goksen, G.; Sunita Singh, Łopusiewicz, L. Recent Progress on UV-light Barrier Food Packaging Films – A Systematic Review. Innovative Food Sci. Emerging Technol. 2024, 91, 103550. DOI: 10.1016/j.ifset.2023.103550.