Vacuum Skin Packaging Research Articles

CHEMICAL CHANGES AND SENSORY EVALUATION OF CHANNEL CATFISH AS AFFECTED BY DIET, PACKAGING METHOD AND FROZEN STORAGE

AbstractFillets from farm‐raised channel catfish (Ictalurum punctatus) fed diets containing various amounts of protein were packaged by the following methods: polyvinylidene chloride (PVDC) film overwrapping, vacuum packaging with Eva bag and vacuum skin packaging. Packaged fillets were stored at —28C for 90 days. Chemical and sensory changes were determined. Neither the packaging method nor protein content of diet had a significant (p < 0.05) effect on TBA number of frozen stored catfish. No significant differences on free fatty acid content of catfish packaged in different methods were also found. However, sensory evaluation revealed that greasiness of cooked catfish decreased as toughness of fillet texture increased throughout entire frozen storage.

The influence of different centralised pre-packaging systems on the shelf-life of fresh pork

The influence of different centralised pre-packaging systems (PVC, modified atmosphere packaging (MAP), 25% CO 2 and 75% O 2, vacuum skin packaging (VSP) and the mother bag concept, 100% CO 2) on the shelf-life (0, 7, 14 and 21 days at 0°C) of fresh pork was determined using microbiological, colour, odour and acceptability characteristics. All the packaging treatments were equally efficient for the first 4 days of retail display. In the extended shelf-life study (7, 14 and 21 days) the mother bag centralised packaging system gave the most promising shelf-life results (21 days) and was also judged superior in terms of odour. Modified atmosphere packaging (14 days) and VSP (7 days) may be considered as other possible options.

Development of rancidity in salmonoid steaks during retail display

The quality of wild salmon and farmed rainbow trout from aquaculture, both packed in transparent vacuum-skin packaging, was followed during storage for 6 months in an illuminated freezer cabinet (product temperature -17 degrees C, half of the packs protected against light, and half of the packs fully exposed to light), combining (a) colour determination of the carotenoid-pigment flesh by tristimulus colorimetry, (b) determination of thiobarbituric-acid-reactive substances (TBA value), (c) carotenoid analysis and, at the end of the storage experiment, (d) sensory evaluation. Rancidity developed faster in steaks of wild salmon (TBA increased during 6 months of storage from 2.8 mumols malonaldehyde/kg flesh to 12.5 mumols/kg for light-protected packages, and to 17.6 mumols/kg for packages exposed to fluorescent light) as compared to steaks of farmed rainbow trout (TBA increased from 1.2 to 5.8 mumols/kg, independent of light exposure), a finding also confirmed by sensory evaluation. In both products, the carotenoid pigment was identified as astaxanthin; salmon steaks, the product more susceptible to developing rancidity, had the lower astaxanthin content (rainbow trout 9.1 mg/kg flesh, salmon 4.9 mg/kg, prior to storage). While the astaxanthin content remained virtually constant in salmon steaks during storage, the content decreased significantly in steaks of rainbow trout, an observation which suggests the role of astaxanthin as a sacrificial protector against radical processes.