RESUMO
Chitosan coating containing nanoliposomes loaded with licorice root extract was prepared to investigate shrimp's shelf life and anti-browning function during 20 days of ice storage. 1% licorice root hydroethanolic extract (LHE) was encapsulated in nanoliposomes or coated with chitosan, and then the shrimp were immersed in coating solutions. LHE treatment had the lowest browning indices (5 and 1.02), TBA (0.32 mg MDA/kg), and FFA (0.01%). Chitosan-coated LHE treatment (Ch-LHE) showed the best performance for TVN, microbial counts, and discoloration. PV, WHC, and cook loss in the treatment with LHE nanoliposome coated with chitosan (Ch-N-LHE) were measured at acceptable levels of 0.53 meq/kg, 86.12%, and 15.06%, respectively. Experiments showed that pure or encapsulated LHE is an effective method for increasing the quality and preventing the browning of shrimp. Additionally, due to its cost-effectiveness and health benefits, it can be an effective natural substitute for sodium metabisulfite at the global export level.
RESUMO
Effect of phlorotannins (PT) treatments on the ployhenoloxidase (PPO) activity and quality changes of Pacific white shrimp during a 16-day period of storage in ice were studied. Among seaweeds, Sargassum tenerimum had the highest amount of PT (10.00â¯mg phloroglucinol/g), PPO inhibitory activity (71.94%) and therefore selected for PT extraction. The shrimp treated with 5% PT (w/v) showed the least melanosis score, pH, TVB-N values and lipid oxidation among all treatments throughout the iced storage. Lower counts of mesophilic and psychrotrophic bacteria (1-2â¯logâ¯CFU/g) were obtained with 5% PT treatment compared to the control at the last day of storage (Pâ¯<â¯0.05). Sensory evaluation proved that 5% PT treatment could cause a 4-days increase in the shelf-life of shrimp compared to the control, PT1% and PT2% treatments. Therefore, 5% phlorotannins from S. tenerimum could be used as a safe melanosis inhibitor for the treatment of shrimp.