ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Shelf life extension of refrigerated, vacuum-packed rainbow trout dipped in an alginate coating containing an ethanolic extract and/or the essential oil of Mentha Aquatica

Zahra Alizadeh Amoli, Tooraj Mehdizadeh, Hossein Tajik, and Maryam Azizkhani

Urmia University, Urmia, Iran

E-mail: t.mehdizadeh@urmia.ac.ir

Abstract: In the present study, we investigated both the antioxidant and antimicrobial effects of a sodium alginate coating containing an ethanolic extract and/or the essential oil of Mentha aquatic, as well as the impact of vacuum packaging on the shelf life of refrigerated rainbow trout. Treated samples were evaluated chemically (pH, total volatile basic nitrogen, peroxide, and thiobarbituric acid values), organoleptically (color, odor, and texture) and microbiologically (aerobic mesophilic bacteria, Enterobacteriaceae, psychrophilic bacteria, and H₂S-producing bacteria) after 0, 3, 6, 9, and 12 days of refrigeration. We found that trout coated with alginate containing both the essential oil and the extract of this herb had lower values for pH, total volatile basic nitrogen, peroxide, and thiobarbituric acid (p < 0.05) compared to the control. Microbiological tests demonstrated that all treatments were effective in delaying the growth of bacteria during refrigerated storage. Sensory evaluation also showed greater acceptance of treated samples. The results of the chemical, microbial, and sensory analyses showed that vacuum-packaged trout coated with alginate containing both the essential oil and the ethanolic extract of Mentha aquatica maintained the quality characteristics of the fish and extended its shelf life during refrigerated storage.

Keywords: Mentha aquatica ; Rainbow trout ; Shelf life ; Sodium alginate ; Coating 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-019-00808-8

Chemical Papers 73 (10) 2541–2550 (2019)