Combined Effect of Dipping in Oxalic or in Citric Acid and Low O2 Modified Atmosphere, to Preserve the Quality of Fresh-Cut Lettuce during Storage.

Bernardo Pace,Maria Cefola,Imperatrice Capotorto,Michela Palumbo,Sergio Pelosi

doi:10.3390/foods9080988

Bernardo Pace, Maria Cefola + Show 3 more

Open Access

https://doi.org/10.3390/foods9080988

Copy DOI

Abstract

Leaf edge browning is the main factor affecting fresh-cut lettuce marketability. Dipping in organic acids as well as the low O2 modified atmosphere packaging (MAP), can be used as anti-browning technologies. In the present research paper, the proper oxalic acid (OA) concentration, able to reduce respiration rate of fresh-cut iceberg lettuce, and the suitable packaging materials aimed to maintaining a low O2 during storage, were selected. Moreover, the combined effect of dipping (in OA or in citric acid) and packaging in low O2 was investigated during the storage of fresh-cut iceberg lettuce for 14 days. Results showed a significant effect of 5 mM OA on respiration rate delay. In addition, polypropylene/polyamide (PP/PA) was select as the most suitable packaging material to be used in low O2 MAP. Combining OA dipping with low O2 MAP using PP/PA as material, resulted able to reduce leaf edge browning, respiration rate, weight loss and electrolyte leakage, preserving the visual quality of fresh-cut lettuce until 8 days at 8 °C.

Highlights

Iceberg lettuce (Lactuca sativa L.) is considered one of the most popular vegetable and represent the primary fresh-cut product processed in Italy as well as in many other European and North America countries
Saltveit [8] reports that modified atmosphere packaging (MAP) with low O2 and high CO2 was successfully applied to control browning for the iceberg lettuce, whereas Gorny [9] shows that atmospheres with O2 values between 0.5 kPa and 3 kPa are recommended for iceberg lettuce
Citric acid has been extensively used for its anti-browning activity in minimally processed fruits and vegetables [12] and on fresh lettuce [5]. It was reported the efficiency of oxalic acid in preventing lettuce browning and extending the shelf life of fresh-cut fruits and vegetables [5,10,11,13,14,15,16]. Starting from these considerations, the goal of the present work is to study the combined effect of dipping in oxalic or citric acid and low O2 MAP to control the leaf edge browning of fresh-cut lettuce

Summary

Introduction

Iceberg lettuce (Lactuca sativa L.) is considered one of the most popular vegetable and represent the primary fresh-cut product processed in Italy as well as in many other European and North America countries. In particular PPO catalyzes both hydroxylation of monophenols to o-diphenols and oxidation of colorless o-diphenols to o-quinones give brown pigments to cut tissues. While POD promote the oxidation of phenols to quinones in the presence of hydrogen peroxide [1]. To limit these changes that affect quality, supplementary techniques have been used in addition to the low temperature, such as modified atmosphere, chemical dipping based on different organic acids, edible coatings, heat treatments [1,5,6,7].

Objectives

Methods

Results

Conclusion