Hierarchical Porous Cryogel Label

Fish freshness color indicator

A cryogel label with interconnected macropores, built from cotton staple fiber skeleton, chitosan matrix, and mulberry anthocyanin indicator, offering higher ammonia sensitivity and color stability than dense film indicators.

Guo, Xiaojia · Xianshan, Zhang · Ting, Zhang · Shi, Liu · Sheng, Chen · Chen, Lang · Wu, Wenjin · Wang, Lan

Food Research International 2026

Specifications

Porosity

{'zh': '97.80', 'en': '97.80'} %

Anthocyanin migration

{'zh': '53.8', 'en': '53.8'} %

Color stability

{'zh': '5', 'en': '5'}

Correlation between label ΔE and fish TVB-N

{'zh': '0.9575', 'en': '0.9575'} R²

Advantages

Superior sensitivity

The interconnected macroporous structure increases the contact area with ammonia, giving the cryogel label superior sensitivity over dense film indicators.

Enhanced food safety

The label uses fully bio-based, non-toxic cotton staple fiber, chitosan, and mulberry anthocyanin, avoiding food safety risks from synthetic dye migration.

Good color stability

The label exhibits color stability with ΔE < 5, ensuring reliable color retention for accurate freshness assessment.

Applications

• Aquatic product freshness monitoring：Real-time color change indicates fish freshness, replacing time-temperature indicators.
• Food freshness indicator packaging：Attached inside packaging to show food freshness and reduce waste.
• Bio-based intelligent packaging：Made from natural materials, degradable and non-toxic, aligning with green packaging trends.
• Degradable pH indicator materials：Sensitive to pH changes with color response, and the materials are biodegradable.