Preservation of cold-stored guavas influenced by package materials

The objective of this study was to evaluate the influence of package materials on the preservation of cold-stored 'Kumagai' guavas. The treatments were: PO2, co-extruded polyolephinic film with gas injection (5% O-2/5% CO2/Nz); PO3, co-extruded polyolephinic film with gas injection (5% O-2/5% CO2/N-2); LDPE, linear low density polyethylene film; LDPE-gas, linear low density polyethylene film with gas injection (3% O-2/8% CO2/N-2); PVC, polyvinylchloride stretch film; PO1, co-extruded polyolephinic film and control: non-packaged guavas. Guavas were stored at 10 +/- 1 degrees C/80-90% RH for 21 days, and then transferred to room temperature. Gas composition within the package headspace was analysed during storage and the physical and chemical characteristics of the guavas were evaluated daily during ripening. The modified atmosphere provided by PO1 film was insufficient to promote the benefit of senescence control. Although PVC provided an atmosphere close to that recommended, it did not preserve the colour and pulp firmness. PO2, PO3, LDPE and LDPE-gas retarded the senescence process of the guavas during 21 days at 10 degrees C plus 2 days at room temperature, but harmed the normal ripening of guavas in some aspects. This can be explained by reduced O-2 and elevated CO2 levels within these four packages. None of the packages influenced the titratable acidity and the soluble solids, but they did harm ascorbic acid synthesis. Copyright (c) 2005 John Wiley & Sons, Ltd.