The Use of Opuntia ficus-indica Mucilage and Aloe arborescens as Edible Coatings to Improve the Physical, Chemical, and Microbiological Properties of ‘Hayward’ Kiwifruit Slices

Giuseppe Sortino,Roberta Passafiume,Paolo Inglese,Vittorio Farina,Alessio Allegra

doi:10.3390/horticulturae8030219

Abstract

Edible coatings (EC) with mucilage of Opuntia ficus-indica or Aloe arborescens are promising to extend the shelf life of fresh-cut fruit products by reducing weight loss and microbial spoilage. In this work, fresh-cut kiwifruits (cv. Hayward) were coated in solutions with mucilage extracted from Opuntia ficus-indica (MC) and A. arborescens (AL). We used three alternative treatments with AL or MC, MC+AL, and with distilled water as control, and stored in passive atmosphere at 5 °C for 3, 5, 7, and 9 d, respectively. For all treatments at each storage period, firmness, weight loss, color, visual quality score, respiration rate, pectin content, and microbiological characteristics were observed. The treatments with mucilage and A. arborescens applied on fresh-cut kiwi slices showed different significant effects until 9 days of storage, in terms of firmness and total pectin. Microbial spoilage analysis revealed the beneficial effects of this strategy after 3 d, particularly in terms of bacteria and yeast. A. arborescens provided a reduction of microbial activity, probably due to the higher quantity of aloin if related to Aloe species. Furthermore, the treatment with MC and AL increased the total pectin content, showing positive effects in terms weight loss and firmness. The results showed that the MC+AL treatment improved the visual score of fresh-cut kiwi fruit until 7 d of storage.

Highlights

Kiwifruit (Actinidia spp.) is a typical climacteric fruit that, after harvest, goes through three distinct softening phases that are temporally well separated
We focused our study on the effects of O. ficus-indica (OFI) mucilage with A. arborescens on the visual quality score, firmness, and microbial load of minimally processed kiwifruit slices, during 9 days of storage
Kiwifruit slice solid soluble content (SST) did not change significantly between treatments during storage time, but after 3 d, the sample slices treated with mucilage (MC) showed significant differences compared to the other treatments (CTR, AL, mL glycerol as a plasticizer (MC+AL))

Summary

Introduction

Kiwifruit (Actinidia spp.) is a typical climacteric fruit that, after harvest, goes through three distinct softening phases that are temporally well separated. Pectin retained in the cell wall starts to “soften” during ripening; this process clearly precedes both pectin solubilization and depolymerization (Phase 1) [1]. Are processes initiated in the second softening phase, with a peak in the last softening phase, where cell wall disintegration is completed (Phase 3) [1]. Kiwifruits can be stored for a long period and sold for fresh consumption or for processing as fresh-cut. The peeling and slicing involved in minimal fruit processing can cause physical damages, and an increase of polyphenoxidase and peroxidase begins browning in the flesh. In fresh-cut fruit, the rapid softening and deterioration likely involve membrane and cell wall catabolism, accelerated or otherwise altered in response to physical wounding [2]

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