Work

Opuntia ficus-indica extract as a compostable adhesive for price look-up stickers

Year: 2026

Type: article

Abstract: Recent legislation has led to a call for compostable PLU (price look-up) stickers. While compostable ink and sticker materials already exist, the challenge is to find a compostable adhesive. Inspired by indigenous practices, Opuntia ficus-indica , commonly known as prickly pear cactus, cladodes were harvested and the mucilage extracted by simple water-only soaking. This mucilage extract was the primary component in a pressure sensitive adhesive for PLU stickers. The stickers were applied onto apples, grapefruits, avocados, sweet potatoes, and green kiwis, selected for their diverse epicuticular textures and chemical compositions. The stickers demonstrated effective adhesion across all the produce tested, with success on the more challenging textured surfaces. After two weeks, 100% of the apple and avocado stickers, 94% of the grapefruit stickers, 78% of the sweet potato stickers, and 61% of the kiwi stickers were still adhered, with the average adhesion score ranging from 4.67 (± 0.59) out of 5 for the apple stickers to 1.22 (± 1.00) out of 5 for the kiwi stickers. The mucilage was tested for biodegradability, demonstrating a biodegradation half-life of 39 days under home compost conditions (25°C). This PLU sticker adhesive is the first to be identified as home compostable. This study identifies Opuntia ficus-indica mucilage as a viable and eco-friendly base formula for adhesives, considering the plant's drought tolerance and established commercial cultivation.

Source: International Journal of Adhesion and Adhesives

DOI: 10.1016/j.ijadhadh.2026.104463