The research group coordinated by prof. Paolo Inglese from the University of Palermo studied the effect on the quality and shelf-life of packed kiwi slices covered in edible coating made from the mucilage of prickly pears [Opuntia ficus-indica (OFI)].

OFI mucilage was used both on its own or combined with Tween 20. After being treated, samples were stored in a passive atmosphere at 5 ± 1 °C for 3, 5, 7 and 12 days. Researchers measured aspect and flavour, pectin and ascorbic acid content, microbiological characteristics as well as CO2 and O2 concentration. 

Stages of the extraction of mucilage from prickly pears (photo taken from Dr Giuseppe Buggea's dissertation).

The analyses showed that, up to 5 days, kiwi slices were more compact and lost less weight compared to untreated slices. No additional weight loss was recorded after 7 days. Slices covered only in mucilage maintained their compactness for 12 days. Mucilage coating had a positive effect on the aspect and flavour for all 12 days, while the Tween 20 coating showed no improvement compared to untreated slices. 

Although both coatings favoured the development of microbes, and especially of yeasts, the level remained below the threshold throughout the shelf-life. Researchers therefore concluded that OFI mucilage coating preserves the quality of the fresh-cut product stored at 4-6 °C up to 12 days.

Source: Allegra A., Inglese P., Sortino G., Settanni L., Todaro A., Liguori G., 'The influence of Opuntia ficus-indica mucilage edible coating on the quality of 'Hayward' kiwifruit slices', Ottobre 2016, Postharvest Biology and Technology, Vol. 120, pag. 45-51.

Alessio Allegra
Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo
Viale delle Scienze ed. 4 ingresso
H-90128 Palermo