Salmon, Salmo salar, is a fish rich in lipid components including cholesterol. The consumption of salmon requires cooking processes, which could influence the cholesterol. Cholesterol submitted to heat treatments during cooking may be oxidized forming oxisterols called COPs. COPs are potentially cytotoxic, mutagenic, carcinogenic and atherogenic. In view of this, the present study aims to evaluate the effects of thermo oxidation in terms of COPs in salmon. The formation of oxisterols depends on the chemical composition of the food matrix. Salmon is rich in antioxidants such as tocopherols and astaxanthin, and rich in polyunsaturated fatty acids. Preliminary tests of oxidation were carried out on salmon oil using a convection oven (180 °C) and different cooking techniques (traditional and innovative) were applied to salmon fillets: convection oven (TR) at 180 °C, steam oven (FS) at 65 ° and 90 °, sous vide oven (SV) at 65 ° and 90 ° and combined oven (CO) which combines convection hot air-steam. The average cooking time was around 15-20 minutes. Then, a lipid extraction was performed and the determination of COPs and cholesterol in salmon involved cold saponification. In addition, a purification by SPE (solid phase extraction) was carried out for COPs. Cholesterol and COPs were analyzed using gas chromatography coupled with mass spectrometry (GC-MS). The data obtained revealed that fresh salmon does not contain COPs, while oxidation of fresh salmon oil (without COPs) in a convection oven at 180 °C for 3 hours has developed the following COPs: 7-idrocholesterol, 7-idrocholesterol, 5,6-epossicholesterol, 5,6-epossicholesterol and 7 ketocholesterol, for a total of 56.8 mg / kg oil (3% of COPs on cholesterol). The heat treatment carried out on fresh salmon fillets (in convection TR oven, steam cooking FS, in combi oven CO, and sous vide SV) in no case significantly influenced the % of fat % of water and cholesterol. The cooking did not have effect on the oxidation of cholesterol. The only COP identified but not quantified was the 7-ketocholesterol. The heat treatment with not invasive temperatures in salmon, a matrix rich in carotenoids (astaxanthin), tocopherols and polyunsaturated acids, does not promote the formation of COPs.
Il salmone, Salmo salar, è un pesce ricco in componenti lipidiche tra cui il colesterolo. Il consumo di salmone richiede dei processi di cottura, che potrebbero influenzare il colesterolo. Il colesterolo può andare incontro a ossidazione quando subisce trattamenti termici durante la cottura, formando ossisteroli detti COPs. I COPs sono potenzialmente citotossici, mutagenici, cancerogeni e aterogenici. In vista di questo, il presente studio ha lo scopo di valutare gli effetti della termo ossidazione in termini di COPs nel salmone. La formazione dei COPs dipende anche dalla composizione chimica della matrice alimentare . Il salmone risulta essere ricco in antiossidanti come tocoferoli e astaxantina, e ricco in acidi grassi polinsaturi. Sono state effettuate prove preliminari di ossidazione dell'olio di salmone in forno ventilato a 180 °C e poi prove di differenti cotture (tradizionali e innovative) su filetti di salmone: forno a convezione (TR) a 180°, forno a vapore (FS) a 65° e 90°, forno sous vide (SV) a 65° e 90° e forno combinato (CO) che combina convezione aria calda-vapore. Il tempo medio di cottura è stato di circa 15-20 minuti. Successivamente è stata eseguita una estrazione lipidica. La determinazione dei COPs e colesterolo nel salmone ha previsto una saponificazione a freddo. In aggiunta per i COPs è stata eseguita una purificazione mediante SPE (estrazione in fase solida). Il colesterolo e COPs sono stati analizzati utilizzando la gascromatografia accoppiata alla spettrometria di massa (GC-MS). I dati ottenuti rivelano che il salmone fresco non contiene COPs, mentre l’ossidazione dell’olio di salmone fresco (privo di COPs) in forno ventilato a 180 °c per 3 ore ha sviluppato i seguenti COPs: 7-idrossicolestorolo, 7-idrossicolesterolo, 5,6-epossicolesterolo, 5,6-epossicolesterolo e 7chetocolesterolo, per un totale di 56.8 mg/kg olio (3% di COPs su colesterolo). Il trattamento termico condotto su filetti di salmone freschi (in forno ventilato TR, cottura a vapore FS, in forno combi CO, e sous vide SV) in nessun caso ha significativamente influenzato la % di grasso, % di acqua e colesterolo. Le cotture effettuate non hanno avuto alcun effetto sull’ossidazione del colesterolo. L’unico COP identificato ma non quantificato è stato il 7chetocolesterolo.Il trattamento termico con temperature non invasive nel salmone, una matrice ricca in carotenoidi (astaxantina), tocoferoli e acidi polinsaturi, non promuove la formazione dei COPs.
Effetto del trattamento termico sui prodotti di ossidazione del colesterolo nel salmone (Salmo salar)
TITTI, EDOARDO
2018/2019
Abstract
Salmon, Salmo salar, is a fish rich in lipid components including cholesterol. The consumption of salmon requires cooking processes, which could influence the cholesterol. Cholesterol submitted to heat treatments during cooking may be oxidized forming oxisterols called COPs. COPs are potentially cytotoxic, mutagenic, carcinogenic and atherogenic. In view of this, the present study aims to evaluate the effects of thermo oxidation in terms of COPs in salmon. The formation of oxisterols depends on the chemical composition of the food matrix. Salmon is rich in antioxidants such as tocopherols and astaxanthin, and rich in polyunsaturated fatty acids. Preliminary tests of oxidation were carried out on salmon oil using a convection oven (180 °C) and different cooking techniques (traditional and innovative) were applied to salmon fillets: convection oven (TR) at 180 °C, steam oven (FS) at 65 ° and 90 °, sous vide oven (SV) at 65 ° and 90 ° and combined oven (CO) which combines convection hot air-steam. The average cooking time was around 15-20 minutes. Then, a lipid extraction was performed and the determination of COPs and cholesterol in salmon involved cold saponification. In addition, a purification by SPE (solid phase extraction) was carried out for COPs. Cholesterol and COPs were analyzed using gas chromatography coupled with mass spectrometry (GC-MS). The data obtained revealed that fresh salmon does not contain COPs, while oxidation of fresh salmon oil (without COPs) in a convection oven at 180 °C for 3 hours has developed the following COPs: 7-idrocholesterol, 7-idrocholesterol, 5,6-epossicholesterol, 5,6-epossicholesterol and 7 ketocholesterol, for a total of 56.8 mg / kg oil (3% of COPs on cholesterol). The heat treatment carried out on fresh salmon fillets (in convection TR oven, steam cooking FS, in combi oven CO, and sous vide SV) in no case significantly influenced the % of fat % of water and cholesterol. The cooking did not have effect on the oxidation of cholesterol. The only COP identified but not quantified was the 7-ketocholesterol. The heat treatment with not invasive temperatures in salmon, a matrix rich in carotenoids (astaxanthin), tocopherols and polyunsaturated acids, does not promote the formation of COPs.| File | Dimensione | Formato | |
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Tesi Edoardo Titti.pdf
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Descrizione: Tesi sperimentale- Effetto del trattamento termico sui prodotti di ossidazione del colesterolo nel salmone.
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https://hdl.handle.net/20.500.12075/5869