Effect of film packaging and storage temperature on physical and chemical changes in fresh-cut green asparagus

Abstract

The effect of two packaging materials, Film 1 (polyvinylchloride film, manually extensible, 12 μm thickness, O2 permeability of 22,000 cm3/m2/24 h/atm) and film 2 (polyethylene film, 13 μm thickness, heat shrinkable, O2 permeability of 8,500 cm3/m2/24 h/atm) on changes in oxygen, carbon dioxide and ethylene concentrations within film packaging, weight losses, chemical parameters and textural properties of fresh-cut green asparagus (Asparagus officinalis L.) were evaluated during three weeks of storage at 2 or 10°C. During the first two days of storage, in-package carbon dioxide and ethylene concentration increased progressively, while oxygen level decreased. An overall decrease in pH, sucrose and fructose content was observed while an increase in titratable acidity was observed in non-packaged asparagus. A significant increase in total phenols and total soluble solids was recorded, while in Film 2 at 10°C significant decreases were detected in total soluble solids. Antioxidant activity did not change in asparagus packaged at 2°C while in unpackaged and in Film 1 and 2 at 10°C there were significant decreases. Ascorbic acid contents declined rapidly after storage in all samples. Weight loss increased markedly in non-packaged asparagus; in asparagus packaged with Film 1 at 10°C significant differences were detected with respect to the other packaged treatments. Both packaging materials preserved rheological properties of spears whereas un-packaged asparagus lost crispness rapidly. The overall results showed that the best storage conditions to extend the shelf-life of fresh-cut green asparagus were achieved by combining packaging and storage at 2°C.