Preliminary study on edible film with a natural plant extract to improve quality of fresh fruits for supply chains.

摘要

There is no report in Chile about quality in the supplier chains of fruits and vegetables which are often visibly deteriorating in the retail market. This study attempts to enhance their quality with simple techniques like edible coatings/films acting as bioactive packaging, with the extract of the native plant murta (Ugni molinae), ecotype Soloyo Chico (SC) of Pumalal, near Temuco, Chile. The leaf water extract, rich in polyphenols (HPLC-MS chromatogram shows that SC has more myricetin than another ecotype), was evaluated for antioxidant activity by measuring its ability to scavenge DPPH radicals and protect toward linoleic acid peroxidation in micelles of sodium dodecyl sulfate. It presented a significantly better antioxidant capacity than the other ecotype tested. The edible coatings were prepared from carboxymethylcellulose with glycerol and sunflower oil as plasticizers (CMC), and water (CMC-H2O) or extract (CMC-SC), spreading 20 ml of film forming solutions on a 18x9 cm area, dried at 25 degrees C. Films were peeled off (0.016-0.046 mm thickness), water vapour permeability was measured with cup-method, and gas permeability (O2 and CO2) was measured by isostatic method/gas chromatography. Compared with the CMC-H2O, films with CMC-SC act as barrier to O2 but not to H2O and CO2, modifying significantly (P<0.05) the permeability of the film. Apricot (Prunus armeniaca cv. Patterson) fruits coated with either CMC-SC or CMC-H2O, dried at 25 degrees C and the control fruits (without any treatment) were stored at 0 degrees C, 95% RH. After 14 days, a better weight retention and colour (measured with a tristimulus colorimeter) as lightness (L*), chroma and hue, although not significant, were observed with CMC-SC compared to CMC-H2O. Both CMC treatments were significantly better (P<0.05) than the control fruits. The results show that these edible films can improve shelf life of horticultural products, which could be applied in the supply chains..