ABSTRACT
This study compared the potential of an aqueous extract of an edible mushroom (Flammulina velutipes) to prevent melanosis in cultured Kuruma shrimp (Marsupenaeus japonicus) with other antimelanosic compounds in vivo. The mushroom extract contained 9.1 mg/mL ergothioneine (ESH). Immersion of live full-grown shrimp in a 0.5% w/v solution of mushroom extract significantly reduced PPO activity in shrimp hemolymph. In addition, expression of the prophenoloxidase (proPO) gene decreased in hemocytes, suggesting that the extract blocked the activation of the proPO cascade. Consequently, the development of melanosis in the treated shrimp was significantly suppressed during ice storage. Treatment with a 0.05% w/v solution of sodium ascorbate and 4-hexyl-1,3-benzenediol had the same effect. In vitro experiments showed that ESH effectively inhibited PPO activity and activation of the proPO cascade in hemocyte lysate supernatant. This study suggests that in vivo application of F. velutipes mushroom extract is an effective natural alternative to synthetic antimelanosic agents to inhibit postmortem melanosis in shrimp. Practical Application: The extract of an edible mushroom (F. velutipes) containing ergothioneine can be a promising natural alternative to synthetic antimelanosic agents used to prevent postharvest melanosis in shrimp and other crustaceans. Furthermore, utilization of the mushroom trimmings could also help address the growing concerns on the disposal of such agricultural wastes and instead use it into a novel purpose as a source of antimelanosic and antioxidants for food and industrial application.
Subject(s)
Antioxidants/pharmacology , Complex Mixtures/pharmacology , Flammulina/chemistry , Food Preservation/methods , Penaeidae/drug effects , Shellfish/analysis , Animals , Antioxidants/analysis , Antioxidants/chemistry , Aquaculture , Catechol Oxidase/antagonists & inhibitors , Catechol Oxidase/blood , Catechol Oxidase/genetics , Catechol Oxidase/metabolism , Color , Complex Mixtures/chemistry , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Enzyme Inhibitors/analysis , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Enzyme Precursors/blood , Enzyme Precursors/genetics , Enzyme Precursors/metabolism , Ergothioneine/analysis , Ergothioneine/pharmacology , Food Handling , Gene Expression Regulation, Enzymologic/drug effects , Hemocytes/drug effects , Hemocytes/enzymology , Hemocytes/metabolism , Hemolymph/drug effects , Hemolymph/enzymology , Immersion , Penaeidae/enzymology , RNA, Messenger/metabolism , SolubilityABSTRACT
Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) were extracted from scale of spotted golden goatfish (Parupeneus heptacanthus) with the yields of 0.46% and 1.20% (based on dry weight basis), respectively. Both ASC and PSC were characterised as type I collagen, containing α1 and α2 chains. ß and γ components were also found in both collagens. Based on FTIR spectra, the limited digestion by pepsin did not disrupt the triple helical structure of collagen. ASC and PSC contained glycine (336-340 residues/1000 residues) as the major amino acid and had imino acids of 186-189 residues/1000 residues. Maximal transition temperatures (Tmax) were 41.58 and 41.01°C for ASC and PSC, respectively. From zeta potential analysis, net charge of zero was found at pH 4.96 and 5.39 for ASC and PSC, respectively. Both collagens exhibited high solubility in acidic pH (2-4) and were soluble in the presence of NaCl at concentration up to 20 and 30g/l for ASC and PSC, respectively.
ABSTRACT
The antimelanosic and antioxidative properties of a hot water extract prepared from the fruiting body of the edible mushroom (Flammulina velutipes) were evaluated by dietary supplementation in Kuruma shrimp (Marsupenaeus japonicus) for possible aquaculture application. The extract contained ergothioneine (ERT) at a level of 2.05 mg/mL. A commercial standard of l-ergothioneine (l-ERT) and the mushroom extract showed inhibitory activity against mushroom polyphenoloxidase (PPO). Feeding of the extract had no adverse effects on the immune systems of the shrimp under the present experimental conditions. Supplementation of the extract in the diet significantly suppressed PPO activities in the hemolymphs of the shrimp. Expression of the prophenoloxidase (proPO) gene decreased in the hemocyte of the Kuruma shrimp fed with the mushroom extract. Consequently, development of melanosis was significantly suppressed in the supplement fed shrimp during ice storage. Lipid oxidation was also effectively controlled in the supplement fed group throughout the storage period. In vitro experiments showed that l-ERT effectively inhibited the activation of proPO in the hemocyte lysate supernatant (HLS). The transcript of the proPO gene in the hemocyte showed lower expression in the l-ERT-treated HLS. It was concluded that dietary supplementation of the mushroom extract in shrimp could be a promising approach to control post mortem development of melanosis and lipid oxidation in shrimp muscles.
