Effects of pretreatment on quality characteristics of freeze dried white shrimp (Penaeus vannamei) during storage

To improve the storage stability of freeze dried shelled shrimps, effects of different osmotic dehydration agents, i.e. maltodextrin, whey protein isolate, combination of maltodextrin and whey protein isolate on the astaxanthin content, apparent density, rehydration ratio, and water hold capacity were investigated. Effects of treatment with distilled water, considered as a control group were also compared to investigate the efficiency of treatments.The results showed that osmotic dehydration with maltodextrin as agent before freeze drying could effectively maintain the structure stability, inhibit the deformation and increase the water hold capacity of freeze dried shelled shrimps.Osmotic dehydration with whey protein isolate as agent could decrease astaxanthin loss rate and apparent density, and increase water hold capacity of freeze dried shelled shrimps.Storage stability of freeze dried shelled shrimps could be improved by osmotic dehydration treatment with maltodextrin and whey protein isolate as osmotic agents.