Prickly pear (Opuntia ficus-indica) cladodes were extracted with an aqueous mucilaginous solution to create an edible film for preserving strawberries and feijoa. The peel of kumquat (Fortunella spp.; edible exocarp) was extracted to obtain a bioactive compound with antioxidant and antimicrobial properties. Three sample groups were prepared: control (uncoated fruit samples), neat film-coated fruits without kumquat extract (FLN), and kumquat-enriched film-coated fruits (FLK) for coating the fruit samples. All samples were stored at 4 °C for 14 days. The water contact angle of the plasticized films was 120°, indicating they are hydrophobic. Strawberry color results showed a significant reduction (p < 0.05) in redness across different film formulations. Uncoated samples retained redness better than coated samples. For feijoa, a significant decrease (p < 0.05) in CIE a* was observed in the control group, but the reduction in greenness for film-coated feijoa was not statistically significant (p > 0.05). The decline in antioxidant activity of feijoas was not significantly different among the samples (p > 0.05). In the case of strawberries, the control and FLN group samples maintained their antioxidant capacity; the decrease in FLK samples was not significant (p > 0.05). Feijoa weight loss was greater in FLN samples than in FLK and uncoated samples at the end of the storage period. However, in the FLK strawberries, weight loss was greater than in the FLN and control samples. The pH increased in FLK feijoas, while FLN and control feijoas did not show significant (p < 0.05) changes. Strawberry samples also showed increases in pH; however, increases were significantly higher in film-coated strawberries (p < 0.05) than in control samples (p > 0.05). The pH increases in coated strawberry samples indicate senescence of the fruit during storage. In terms of microbiological aspects, the highest total aerobic mesophilic count was observed in the control groups compared with the coated samples in both fruits. While yeast and mold counts were lower in feijoas than in strawberries, they still showed significant variation. The film formulations used in this study provided a physical barrier, preventing an increase in microbial numbers beyond 7 logs, indicating that the food was not spoiled. The plasticized films derived from prickly pear leaves showed promising results as alternative packaging solutions in a circular economy. Graphic abstract

Assessment of Kumquat-Enriched Prickly Pear Edible Films for Preservation of Strawberries and Feijoas

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发表日期：

2026年1月8日

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Melike Ünal,
Rukiye Öz,
Sinan Uzunlu

摘要

Prickly pear (Opuntia ficus-indica) cladodes were extracted with an aqueous mucilaginous solution to create an edible film for preserving strawberries and feijoa. The peel of kumquat (Fortunella spp.; edible exocarp) was extracted to obtain a bioactive compound with antioxidant and antimicrobial properties. Three sample groups were prepared: control (uncoated fruit samples), neat film-coated fruits without kumquat extract (FLN), and kumquat-enriched film-coated fruits (FLK) for coating the fruit samples. All samples were stored at 4 °C for 14 days. The water contact angle of the plasticized films was 120°, indicating they are hydrophobic. Strawberry color results showed a significant reduction (p < 0.05) in redness across different film formulations. Uncoated samples retained redness better than coated samples. For feijoa, a significant decrease (p < 0.05) in CIE a* was observed in the control group, but the reduction in greenness for film-coated feijoa was not statistically significant (p > 0.05). The decline in antioxidant activity of feijoas was not significantly different among the samples (p > 0.05). In the case of strawberries, the control and FLN group samples maintained their antioxidant capacity; the decrease in FLK samples was not significant (p > 0.05). Feijoa weight loss was greater in FLN samples than in FLK and uncoated samples at the end of the storage period. However, in the FLK strawberries, weight loss was greater than in the FLN and control samples. The pH increased in FLK feijoas, while FLN and control feijoas did not show significant (p < 0.05) changes. Strawberry samples also showed increases in pH; however, increases were significantly higher in film-coated strawberries (p < 0.05) than in control samples (p > 0.05). The pH increases in coated strawberry samples indicate senescence of the fruit during storage. In terms of microbiological aspects, the highest total aerobic mesophilic count was observed in the control groups compared with the coated samples in both fruits. While yeast and mold counts were lower in feijoas than in strawberries, they still showed significant variation. The film formulations used in this study provided a physical barrier, preventing an increase in microbial numbers beyond 7 logs, indicating that the food was not spoiled. The plasticized films derived from prickly pear leaves showed promising results as alternative packaging solutions in a circular economy.

Graphic abstract