100B-18 |
The display life of fresh beef steaks (Gluteus medius m.) after storage in masterpacks under modified atmosphere (100%CO2) with O2 scavengers |
A. C. Venturini1, C. C. CONTRERAS2, C. I. G. L. Sarantópoulos, K. M. V. A. B. Cipolli, H. K. Arima, and B. H. Rodrigues. (1) Depto. Ciência e Tecnologia de Alimentos, Universidade de São Paulo, Av. Pádua Dias, 11, Caixa Postal 9 - Piracicaba, 13418-900, Brazil, (2) Centro de Tecnologia de Carnes, Instituto de Tecnologia de Alimentos, Av. Brasil, 2880, Caixa Postal 139 - Campinas, 13073-001, Brazil Previous research showed that residual O2 is rapidly stripped from 100% CO2 modified atmosphere packaging by formation of MetMb in beef steaks of low colour stability irrespective of temperature. Beef steaks discoloration can be prevented in modified atmosphere by using O2 scavengers. However the large scavenging capacity currently used to rapidly reduce the residual O2 may be uneconomical. This study optimized the use of O2 scavengers to extend the storage life of Gluteus medius muscles, with ineherent low stability colour. Steaks (0,386±0,045kg) were placed in an expanded polystyrene tray and over-wrapped with plastic film having a high OTR. Eight trays and one type of commercial O2 scavengers were placed in each masterpack. Two systems of O2 scavengers were tested: S1=1 sachet/300cc and S2=2 sachets/210cc. Controls system without O2 scavengers were carried out as well. The masterpacks under 100% CO2 were storaged at 4±1oC. Intensities of purple, bright red and brown on the steaks surface were assessed by a six-member panel on a non-structurated scale (0=none and 10=intense) and %discoloration was evaluated on a five-point scale. Colour coordinates were measured in the CIELab system. Aliquots (0.1ml) of appropriate dilutions were spread on duplicates plates of PCA and incubated for 3 days at 21oC for psychrotrophic aerobic and anaerobic analysis. After 15 days, the steaks packaged with S2 had the lowest discoloration (0-5%), the highest red intensity (8.0) and the highest redness value (a*=21.18), when compared to control steaks (p<0.000). However, steaks packaged with S1 and control steaks had comparable (p>0.050) brown areas and failed to bloom. All steaks with or without O2 scavengers had comparable counts of bacteria (105UFCg-1). These results indicated that master packaging under 100% CO2 combined with O2 scavengers can be an appropriate technique for preserving muscles with relative poor color stability for up to 2 weeks, under commercial storage temperatures.
Session 100B, Food Packaging
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