Sensory characteristics of Galician chorizo sausage packed under vacuum and under modified atmospheres
Introduction
Hermetic packaging is an increasingly popular method for the conservation of cured meats. In the case of Galician chorizo sausage, the most widely used method (Fernández-Fernández, Rozas-Barrero, Romero-Rodrı́guez, & Vázquez-Odériz, 1991) is vacuum packing: the product is introduced into the pack, and the air is then removed without replacement by any other gas, creating a pressure differential between the inside and the outside of the pack, which is then sealed hermetically. One of the consequences of this procedure is that the pack (typically a flexible plastic, impermeable to gases and water vapor) adheres closely to the product (Lundquist, 1994).
Another method that is acquiring increasing importance within the sector is packing under modified atmospheres: the product is introduced into the pack, the air is removed and replaced with a known mixture of gases, and the pack is then sealed hermetically. The gases most frequently used are oxygen, nitrogen, and carbon dioxide, though other gases including carbon monoxide, nitrous oxide, and sulfur dioxide have also been proposed (Farber, 1991).
CO2/N2 atmospheres are particularly suitable for the conservation of cured meat products, for a number of reasons including strong inhibition of the growth of the great majority of microorganisms (Roncalés, 1994).
The aim of the present study was to compare the sensory and physicochemical characteristics of Galician chorizos packed under vacuum and under various modified atmospheres (CO2 only, N2 only, 50:50 CO2/N2). We also performed parallel experiments to evaluate the gas permeabilities of the aluminum/polyester/polyethylene laminate used for modified-atmosphere packing.
Section snippets
Sample and treatments
A batch of chorizos was obtained from a manufacturer in Lugo Province in Galicia (northwest Spain). On day 18 of curing (Fernández-Fernández et al., 1997), the chorizos were packed (two per pack) in our laboratory by one of four methods:
(A) Vacuum packing in PA/PE packs;
(B) Packing under CO2 in aluminum/PET/PE packs;
(C) Packing under N2 in aluminum/PET/PE packs;
(D) Packing under 50:50 CO2/N2 in aluminum/PET/PE packs.
(PA, polyamide; PE, polyethylene; PET, polyester)
All lots were packed with a
Comparison of the different storage methods
Table 2 show the results of analyses of variance on sensory decriptors of Galician chorizos. The variables showing significant variation among packing methods were visible fat, lumpiness, external color, and fattiness. Average vaules and standard deviations of these descriptors are listed in Table 3.
For visible fat, Tukey's test revealed significant differences between (a) the chorizos packed under N2 or CO2/N2 and (b) the chorizos packed under CO2 or vacuum (Table 3). Significant differences
Conclusion
The results of this study reveal clear differences between chorizos packed under vacuum and chorizos packed under modified atmospheres. However, there was no consistent pattern of differences between chorizos packed under the different modified atmpospheres (100% N2, 100% CO2, 50:50 N2:CO2), and thus our results do not shed any light on the possible advantages of these different gas mixtures. The material that gave the best results for packaging under modified atmospheres was the
Acknowledgements
The work was supported by the Consellerı́a de Educación e Ordenación Universitaria, Xunta de Galicia, Spain, project XUGA 26l07A96.
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