Effect of quince seed mucilage edible films incorporated with oregano or thyme essential oil on shelf life extension of refrigerated rainbow trout fillets.
The effects of quince seed mucilage film (QSMF) containing oregano (O) or thyme (T) essential oil on shelf life extension of rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage (4°C) were evaluated over a period of 18days. Films were prepared in four different concentrations of essential oils, including 0, 1, 1.5 and 2%. The control and the wrapped fillet samples were analyzed periodically for microbiological (aerobic and psychrotrophic count, Pseudomonas spp., H2S-producing bacteria, lactic acid bacteria, and Enterobacteriaceae), chemical (TBA, TVB-N, TMA-N), and sensory characteristics. Bacteria grew most quickly in trout fillets stored in air, followed by those wrapped with QSMF and the lowest counts were in wrapped samples with QSMF+2%T. Pseudomonas spp., Enterobacteriaceae and LAB counts were significantly lower in samples wrapped with QSMF+2%T. The lowest TBA value was obtained in fillets wrapped QSMF containing 2% oregano essential oil. The strong antioxidant activity of QSMF+2%O was related to the composition of oregano essential oil. The GC analysis of essential oil components revealed that carvacrol (81.85%) was the major component of oregano essential oil. TBA value varied for all treatments and remained lower than 2mg MDA/kg throughout storage. The formation of TVB-N, TMA-N increased with time of storage. TVB-N and TMA-N correlated well with the microbiological data, indicating that along with TVB-N, TMA-N may serve as a useful index for fillets spoilage. QSMF extended the microbial shelf life of rainbow trout fillets by 2days, whereas the QSMF+1%O, QSMF+1.5%O, QSMF+2%O, QSMF+1%T, QSMF+1.5%T and QSMF+2%T resulted in a significant shelf life extension of the trout fillets by 3, 5, 9, 6, 10 and 11days, respectively, as compared to the control samples.
Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, P.O. Box 91775 1163, Mashhad, Iran. Electronic address: m.jouki@yahoo.com.
Mohammad
M
Jouki
Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, P.O. Box 91775 1163, Mashhad, Iran.
Farideh Tabatabaei
FT
Yazdi
Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, P.O. Box 91775 1163, Mashhad, Iran.
Seyed Ali
SA
Mortazavi
Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, P.O. Box 91775 1163, Mashhad, Iran.
Arash
A
Koocheki
Department of Food Science and Technology, Faculty of Agriculture, Urmia University, Urmia, Iran.
Naimeh
N
Khazaei
D000818:Animals; D001419:Bacteria / Q000187:drug effects*; D005516:Food Microbiology; D018857:Food Packaging / Q000379:methods* / Q000592:standards; D005519:Food Preservation / Q000379:methods / Q000592:standards; D006801:Humans; D009822:Oils, Volatile / Q000494:pharmacology*; D017686:Oncorhynchus mykiss / Q000382:microbiology*; D031341:Origanum / Q000737:chemistry*; D027824:Rosaceae / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D013649:Taste; D046930:Thymus Plant / Q000737:chemistry*
D009822:Oils, Volatile
Antimicrobial films; Chemical analysis; Essential oil; Rainbow trout fillet; Wrapping