PACKAGING TECHNOLOGY AND SCIENCE Packag. Technol. Sci. 2005; 18: 71–76 Published online 2 February 2005 in Wiley InterScience (www.interscience.wiley.com). DOI:10.1002/pts.674 Preservation of Cold-stored Guavas Inﬂuenced by Package Materials By Angelo Pedro Jacomino, 1 * Ilana Urbano Bron, 1 Claire Isabel Grígoli de Luca Sarantópoulos, 2 and José Maria Monteiro Sigrist 3 1 Department of Crop Production, ‘Luiz de Queiroz’ College of Agriculture, University of São Paulo, C.P. 9, 13418- 900 Piracicaba, SP, Brazil 2 Center of Packaging Technology, Food Technology Institute, 13073-001 Campinas, SP, Brazil 3 Center of Fruit and Vegetable Technology, Food Technology Institute, 13073-001 Campinas, SP, Brazil 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% CO 2 /N 2 ); PO3, co- extruded polyolephinic ﬁlm with gas injection (5% O 2 /5% CO 2 /N 2 ); LDPE, linear low density polyethylene ﬁlm; LDPE-gas, linear low density polyethylene ﬁlm with gas injection (3% O 2 /8% CO 2 /N 2 ); PVC, polyvinylchloride stretch ﬁlm; PO1, co-extruded polyolephinic ﬁlm and control: non-packaged guavas. Guavas were stored at 10 ± 1°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°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 CO 2 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 © 2005 John Wiley & Sons, Ltd. Received 1 April 2004; Revised 18 June 2004; Accepted 15 October 2004 KEY WORDS: modiﬁed atmosphere; Psidium guajava; plastic ﬁlms; postharvest; modiﬁed atmosphere packaging * Correspondence to: A.P. Jacomino, Department of Crop Production, ‘Luiz de Queiroz’ College of Agriculture, University of São Paulo, C.P. 9, 13418-900 Piracicaba, SP, Brazil Email: jacomino@esalq.usp.br Contract/grant sponsor: FAPESP, Brazil. Copyright © 2005 John Wiley & Sons, Ltd. INTRODUCTION Guava is a perishable fruit with a short shelf-life when stored at room temperature. The use of preservation methods that can increase guava shelf-life whilst-maintaining quality is desirable. In climacteric fruits, reduction of temperature retards the climacteric and consequently the ripen- ing process. 1 The recommended storage tempera- ture for guavas is 9–10°C in order to avoid chilling injury. 2,3 Many studies have evidenced the efﬁciency of plastic packages on guava preservation by reduc- ing the ripening and weight loss. 4–6 Guavas could be stored for 2 weeks when packed in polyethyl- ene ﬁlms impregnated with humidity-absorbent