Stabilization of linseed oil with vitamin E, butylated hydroxytoluene and lipid encapsulation affects fillet lipid composition and sensory characteristics when fed to rainbow trout

• Published in: Animal feed science and technology Vol. 170; no. 1; pp. 53 - 62
• Main Authors: Collins, S.A., Shand, P.J., Drew, M.D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25-11-2011; Elsevier
• Subjects: Antioxidants; Biological and medical sciences; butylated hydroxytoluene; diet; docosahexaenoic acid; eicosapentaenoic acid; Encapsulation; Fatty acids; Feed and pet food industries; fish feeding; fish fillets; fish oils; flavor; Food industries; Fundamental and applied biological sciences. Psychology; growth performance; Linseed oil; lipid composition; odors; Oncorhynchus mykiss; oxidative stability; palm oils; Rainbow trout; Sensory analysis; trout; vitamin E; Encapsulation; LO; OSI; PUFA; Linseed oil; FO; TBARS; Sensory analysis; MDA; Fatty acids; Antioxidants; LA; ALA; EPA; Rainbow trout; FA; DHA; Composition; Stabilization; Vitamin E; Butylated hydroxytoluene; Lipids; Antioxidant
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2011.07.007

An experiment was conducted to determine the effect of adding antioxidants to or encapsulating linseed oil (LO) on its oxidative stability and the growth, fatty acid (FA) composition and sensory properties of rainbow trout. Four pelleted diets differing only in lipid source were prepared: fish oil (FO), LO, LO stabilized with vitamin E (7.5
g/kg) and butylated hydroxytoluene (12.5
g/kg) (stabilized LO) and the stabilized LO encapsulated in hydrogenated palm oil (630
g/kg) (encapsulated LO). The oxidative stability index of the FO and LO diets after 168 days of storage in sealed containers at room temperature were both 0.00
h, whereas those of the stabilized LO and encapsulated LO diets were 9.20 and 11.40
h, respectively. The diets were fed to rainbow trout (22
fish/tank; 7 replicates/treatment; initial weight 31
g) for 168 days. The fish were then euthanized and fillets were analysed for FA composition, malonaldehyde (MDA), colour and sensory attributes. There were no significant differences among treatments on growth performance or MDA levels of fillets. Fish fed FO had higher a* and b* levels on the Hunter L, a, b scale than fish fed any of the LO diets (P<0.05). The total n-3 polyunsaturated FA (PUFA) content of trout fed LO was higher (P<0.05) than those fed FO (355
g/kg of total FA
vs. 276
g/kg) or encapsulated LO diets (289
g/kg). There were no significant differences in fillet eicosapentaenoic acid or docosahexaenoic acid concentrations due to dietary oil. Trained panelists determined that the aroma intensity of the trout fed FO was higher (P<0.05) than those fed stabilized LO and that fish fed FO had a higher rancid aroma and flavour intensity than those fed the other diets (P<0.05). Fillets from fish fed stabilized LO had higher (P<0.05) aroma desirability and overall acceptability than those from fish fed the FO diet. Consumer panelists found no significant differences between the sensory attributes of fish fed the four diets and exhibited no preference among treatments. Addition of antioxidants to or encapsulation of LO improves its oxidative stability during storage and processing and results in fish fillets with FA composition and sensory characteristics equal or superior to fish fed FO.