RAFFAELLA PRETI, GIULIANA VINCI
Laboratory of Commodity Sciences, Department of Management,
University of Rome “La Sapienza”, Via Castro Laurenziano 9, 00161 Rome, Italy

Abstract

The evolution of the antioxidant and sensory properties of six commercially available ready-to-eat salads, rocket, iceberg lettuce, baby lettuce, lamb’s lettuce, curly endive and radicchio, was studied throughout the shelf life. Both the storage under modified atmosphere and in unsealed pouch in a domestic refrigerator were considered and compared. Ascorbic acid, total phenolics content and antioxidant capacity were chosen as the most representative nutritional parameters for this purpose. The data obtained were analyzed by Principal Component Analysis (PCA). Radicchio, lamb’s lettuce and rocket showed an initial higher content of the quality parameters studied and demonstrated a better resistance to air exposure than the other salads, being ascorbic acid the most affected parameter. Modified atmosphere packaging demonstrated to be a very useful and reliable technology to extend nutritional and sensory properties during the shelf life period for all the vegetables studied.

INTRODUCTION

Fruits and vegetables are rich sources of different various bioactive compounds with antioxidant activities, such as vitamins A, C and E and phenolic compounds, which recent studies have shown to be good contributors to the total antioxidant capacity of the foods that contain them (1). Antioxidant components provide protection against harmful free radicals, and have been strongly associated with reduced risk of chronic diseases (2). These facts have led the World Health Organization (WHO) and many health authorities in various countries, to recommend the intake of 400 g of vegetables and fruits, equivalent to 5 portions per day (3).
In particular, recent studies have shown the health effects of lettuce and rocket in preventing cardiovascular diseases and cancer in rats and humans, the healthy properties are attributed to a large supply of antioxidant compounds mainly vitamin C and total phenolics as well as the fibre content (4).
Ready-to-eat vegetables typically involve peeling, slicing, dicing or shredding prior to packaging and storage. Wounding and other minimal processing procedures can cause physiological changes, in ...