89A-2

R. K. KALLEDA¹, P. L. Dawson¹, I. Han¹, F. Chen, H.-J. Kim, and J. E. Toler. (1) Dept. of Food Science & Human Nutrition, Clemson Univ., 116 Newman Hall, Clemson, SC 29634

In general shrimp have short shelf life due to their biological characteristics and body structure. In addition, wild caught shrimp have on board limitations compared to farm raised shrimp. The loss of freshness in shrimp is due to autolytic reactions caused by endogenous enzymes such as poly phenol oxidase (PPO). By the pre-treatment of shrimp with sulfites, the activity of the enzyme PPO can be inhibited, but the enzyme inhibition subsides in 4 to 6 days, possibly due to the oxidation of sulfites. Therefore pre-treatment of shrimp combined with modified atmosphere packaging (MAP) may be an alternative method to extend the shelf life and quality of stored shrimp. The objective of this study was to determine the effect of pre-treatment of sulfites combined with MAP on enhancing the shelf life of shrimp. The different gas mixturesused for MAP were 60%CO₂, 18%O₂, 22%N₂ and 36%CO₂, 64%N₂.The quality and freshness of shrimp was measured by head space analysis, GC-MS, microbiological flora, pH, nucleotide degradation, and sensory analysis. The results indicated that treatment of shrimp with sulfites combined with MAP extended the shelf life of shrimp up to 10 days. Both MAP compositions increased the shelf life of shrimp when compared to air packed shrimp. However the MAP treatment containing more CO₂ was shown to be the best shelf life extender. The higher CO₂ also contained O₂, but the O₂ concentration decreased and the CO₂ concentration increased after 2 days of storage through the end of storage.We concluded that pre-treatment of shrimp with sulfites combined with MAP increases shelf life of shrimp, primarily due to the extended inhibition of PPO activity by CO₂.

Session 89A, Aquatic Food Products: General
2:00 PM - 5:30 PM, Tuesday PM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana