Abstract:

The aim of this work was to evaluate the anti-melanosis and preservative effect of slurry ice in combination
with 4-hexylresorcinol (4-HR) (or sodium phytate) and stable-state chlorine dioxide (ClO2) on fresh shrimp (Litopenaeus
vannamei). The evaluations of sensory quality, total volatile basic nitrogen (TVB-N), total bacterial count, texture profile
and polyphenol oxidase (PPO) activity were done on the treated shrimps during subsequent chilling storage. The results
indicated that the shrimps treated by slurry ice alone were tarnishes, thought the muscle was still soft and springy after 12
days of chilling storage. However, the samples treated by combination of slurry ice with 4-HR (or sodium phytate) and
ClO2 showed clear shells and tentacle; the muscle was still elastic and the sensory quality was significantly better than that
of those solely treated by slurry ice. The combined treatment with slurry ice, 0.030 g/L 4-HR and 0.05 g/L ClO2 showed
the optimal preservative effect on L* and b* values in shrimps during the storage period. After 16 days of storage, the
values of TVB-N, total bacterial count, elasticity, chewiness, and PPO activity of shrimps treated by slurry ice alone were
9.43 mg/100 g, 6.21 (lg(CFU/g)), 0.56 mm, 7.43 mJ, and 10.83 U/g, respectively, compared with the corresponding values
of 15.87 mg/100 g, 4.90 (lg(CFU/g)), 0.80 mm, 8.55 mJ, and 7.67 U/g in those treated by combination of slurry ice with 4-HR
and ClO2, which showed the combined treatment has significantly better preservative effect on shrimps (P < 0.05). Overall,
the combination treatment is suitable for ocean shipping and long-distance transport of chilled shrimp, as well as for storing
fresh shrimp in supermarkets.

Key words: slurry ice, 4-HR, sodium phytate, stable-state chlorine dioxide (ClO2), Litopenaeus vannamei, preservation