Development and characterization of CMCS/gelatin based humidity-responsive hydrogel pads with thyme essential oil release for blueberry preservation

Siting Shi; Ben Niu; Huizhi Chen; Weijie Wu; Chaoyi Shen; Zeyang Bao; Shangyue Xiao; Lishu Wang; Xiangjun Fang; Ruiling Liu; Haiyan Gao

doi:10.1016/j.ijbiomac.2025.145433

Development and characterization of CMCS/gelatin based humidity-responsive hydrogel pads with thyme essential oil release for blueberry preservation

Int J Biol Macromol. 2025 Jun 20;319(Pt 2):145433. doi: 10.1016/j.ijbiomac.2025.145433. Online ahead of print.

Authors

Siting Shi¹, Ben Niu¹, Huizhi Chen¹, Weijie Wu¹, Chaoyi Shen¹, Zeyang Bao¹, Shangyue Xiao¹, Lishu Wang², Xiangjun Fang³, Ruiling Liu⁴, Haiyan Gao⁵

Affiliations

¹ Zhejiang Key Laboratory of Intelligent Food Logistic and Processing, Key Laboratory of Post-Harvest Fruit Processing, Ministry of Agriculture and Rural Affairs, Key laboratory of post-harvest preservation and processing of fruits and vegetables, China National Light Industry, Institute of Food Science, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
² Department of Hematology and Hematopoietic Cell Transplantation, Comprehensive Cancer Center, City of Hope National Medical Center, Duarte, California, USA.
³ Zhejiang Key Laboratory of Intelligent Food Logistic and Processing, Key Laboratory of Post-Harvest Fruit Processing, Ministry of Agriculture and Rural Affairs, Key laboratory of post-harvest preservation and processing of fruits and vegetables, China National Light Industry, Institute of Food Science, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. Electronic address: fangxiangjun2004@163.com.
⁴ Zhejiang Key Laboratory of Intelligent Food Logistic and Processing, Key Laboratory of Post-Harvest Fruit Processing, Ministry of Agriculture and Rural Affairs, Key laboratory of post-harvest preservation and processing of fruits and vegetables, China National Light Industry, Institute of Food Science, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. Electronic address: ruilingliu2005@163.com.
⁵ Zhejiang Key Laboratory of Intelligent Food Logistic and Processing, Key Laboratory of Post-Harvest Fruit Processing, Ministry of Agriculture and Rural Affairs, Key laboratory of post-harvest preservation and processing of fruits and vegetables, China National Light Industry, Institute of Food Science, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. Electronic address: spsghy@163.com.

PMID: 40545084
DOI: 10.1016/j.ijbiomac.2025.145433

Abstract

Blueberries are highly perishable and humidity-sensitive, with humidity promoting microbial growth and accelerating quality deterioration during storage. To address this, we developed a humidity-responsive hydrogel pad to modulate the local microenvironment and enable controlled thyme essential oil (TEO) release, improving antimicrobial efficacy and extending blueberry shelf life. The novel pad was synthesized via solution casting, using carboxymethyl chitosan (CMCS) and gelatin as the matrix, genipin as the cross-linker, and TEO as the active component. The 2C3G pad (CMCS:gelatin = 2:3, w/w) exhibited optimal performance, achieving the highest TEO loading rate (60.02 ± 2.16 %). In vitro release experiments and kinetic modeling confirmed humidity effectively modulates TEO release: cumulative release rates were 10.01 ± 0.27 % at 30 % RH, 32.65 ± 2.10 % at 60 % RH, and 55.59 ± 0.77 % at 90 % RH. Higher gelatin content reduced TEO release under identical RH. Control blueberries showed mold growth after 5 days, whereas 2C3G-treated samples remained mold-free for 20 days, extending shelf life by over 15 days. Thus, the humidity-responsive hydrogel pad significantly improved blueberry quality and shelf life. This study provides a practical technique for designing durable antimicrobial hydrogel pads with excellent properties for food packaging.

Keywords: Blueberry preservation; Humidity-responsive; Hydrogel pad.