The effect of the composite of Aloe vera gel and peppermint essential oil as natural coatings on the postharvest characteristics of kiwifruits

Keeping Fruit Fresh the Natural Way

Anyone who has forgotten a box of kiwifruits in the fridge knows how quickly they can shrivel, mold, and lose their bright flavor. This study explores a simple, plant-based way to keep kiwifruits fresher for longer without relying on synthetic preservatives: a thin, edible coating made from Aloe vera gel and peppermint essential oil. The work matters not just for home cooks, but also for farmers, exporters, and retailers who struggle with fruit waste along the journey from orchard to table.

Why Kiwifruits Go Bad So Quickly

Kiwifruits are what scientists call “climacteric” fruits, meaning they keep ripening after harvest. During storage, they continue breathing, losing water, softening, and becoming more vulnerable to fungi and bacteria. This leads to weight loss, shriveling, off-flavors, and spoilage, especially over long periods in cold rooms or during export. Conventional solutions often involve chemicals that raise health and environmental concerns. The researchers set out to test whether two familiar, natural materials—Aloe vera gel and peppermint essential oil—could work together as a gentle protective shield around the fruit.

A Gentle Shield of Aloe and Mint

To build this shield, the team prepared Aloe vera gel from fresh leaves and peppermint essential oil from dried plant material. They created several mixtures: Aloe vera gel at two strengths (25% and 50%) combined with peppermint oil at three levels (0, 500, and 1000 parts per million). Kiwifruits of the same size and quality were washed, dipped in these mixtures for five minutes, dried, and then stored in covered containers at refrigerator temperature (4 °C) for three months. Every 30 days, the scientists checked how much weight the fruits had lost, how many had spoiled, how sweet and acidic they were, and how well important nutrients and natural protective compounds were preserved.

Slower Spoilage, Better Taste, More Nutrients

The most powerful mixture—50% Aloe vera gel with 1000 ppm peppermint oil—produced striking results after 90 days. Compared with uncoated fruit, these coated kiwis lost 41% less weight and showed 65% less visible spoilage such as mold, discoloration, and softening. The coating also helped the fruits keep a more appealing flavor balance by maintaining sugars and moderating the drop in natural acids, which together shape sweetness and tang. Vitamin C, a key nutrient for immune health, declined in all fruits over time but was much better preserved in coated kiwis. The same was true for plant-based antioxidants like phenols and flavonoids, which help protect cells from damage and contribute to color and taste.

Fighting Invisible Damage Inside the Fruit

Beyond what the eye can see, fruit tissues experience “oxidative stress” during storage—tiny bursts of reactive molecules that damage cell membranes and speed up aging. The study measured markers of this stress, including reactive oxygen species and malondialdehyde, along with protective enzymes such as catalase. Coated fruits, especially those with more Aloe vera and peppermint oil, showed lower levels of damage and stronger activity of natural defense enzymes. At the same time, counts of microbes, molds, and yeasts on the coated kiwis were several times lower than on untreated ones, confirming that peppermint oil and compounds in Aloe vera act as mild natural disinfectants.

What This Means for Your Fruit Bowl

In plain terms, covering kiwifruits with a thin, invisible layer of Aloe vera gel enriched with peppermint oil kept them fresher, firmer, and more nutritious throughout three months in the fridge. The best recipe—50% Aloe vera with the highest level of peppermint oil—combined slower water loss, less mold, better flavor, and higher vitamin and antioxidant levels. While more work is needed to adapt this method for large-scale packing houses and other fruits, the results point toward a future where simple plant-based coatings help cut food waste and reduce reliance on synthetic preservatives, all while delivering tastier fruit to consumers.

Citation: Seyedi, A., Shahdadi, F., Khajehbahrami, A. et al. The effect of the composite of Aloe vera gel and peppermint essential oil as natural coatings on the postharvest characteristics of kiwifruits. Sci Rep 16, 6667 (2026). https://doi.org/10.1038/s41598-026-37376-3

Keywords: kiwifruit storage, edible coatings, Aloe vera gel, peppermint essential oil, postharvest preservation