Textural and Sensory Properties of Fish Sausage from Rainbow Trout

The aim of this study was to determine the textural and sensory properties of fish sausage which were prepared from refrigerated and frozen rainbow trout (Onchorynchus mykiss) and stored for 14 days at 0?4 °C. These two groups of sausages were compared for texture, physical, and sensory properties by carrying out texture profile analysis (TPA), shear test, water holding capacity (WHC), cook loss, color, and sensory analyses. According to TPA and shear test, sausages prepared from frozen fillets exhibited a texture significantly (p < 0.05) weaker than those prepared from refrigerated fillets, but no difference in overall liking was observed.     

Effect of Fish Gelatin Coating Enriched with Oregano Essential Oil on the Quality of Refrigerated Rainbow Trout Fillet

ABSTRACT

In the present study, the effect of fish gelatin coating (FG; 4%, w/v) containing oregano (Origanum vulgare L.) essential oil (OEO; 1.2% w/v) on shelf-life extension of rainbow trout (Oncorhynchus mykiss) fillet stored under refrigerated storage (4 ± 1ºC) was investigated. The control and the treated fish samples were analyzed periodically for chemical (pH; total volatile basic nitrogen, TVB-N; peroxide value, PV; thiobarbituric acid, TBA) and microbiological (total viable count, TVC; psychrotrophic count) characteristics. The FG + OEO treatment produced significantly lower (p < 0.05) TVB-N values as compared to control and FG-coated samples after Day 6 and until the end of the storage period. The TBA values remained low and were found to fluctuate during storage. Results showed that TVC exceeded 6 log CFU g^?1 on Day 8 of storage for control and FG-coated samples and Day 12 for samples coated with FG + OEO. The reduction of 1.05 and 0.83 log CFU g^?1 of psychrotrophic counts was achieved by FG + OEO coating in trout fillet (p < 0.05) as compared with control and FG-coated samples, respectively. Therefore, the incorporation of OEO into FG coating may be a promising method of maintaining the storage quality of the rainbow trout fillet stored at refrigerated temperature.     

Influence of Dietary Lipid and Protein Sources on the Sensory Quality of Organic Rainbow Trout (Oncorhynchus mykiss) After Ice Storage

The influence of dietary protein and lipid sources on the quality of organic rainbow trout (Oncorhynchus mykiss) was studied. The protein and oil sources were fishmeal, fish oil, and organic vegetable protein and oils. Sensory profiling was performed during 3 to 14 days of ice storage along with lipid analyses of the fillet. Overall, the results showed that the sensory characteristics of the trout were affected in different ways during ice storage. The source of lipid seemed to affect the sensory quality at the beginning of the storage period, while the protein source seemed to have a more pronounced impact at the end of the storage period.     

Effects of Sodium Alginate and Chitosan Coating Combined with Three Different Essential Oils on Microbial and Chemical Attributes of Rainbow Trout Fillets

ABSTRACT

Meat products, such as fish meat, are known to be susceptible to undesirable chemical and microbial reactions that characterize spoilage. In this study, the effect of a sodium alginate and chitosan coating incorporated with Mentha piperita, Artemisia dracunculus, and Zataria multiflora essential oils on chemical and microbial attributes of rainbow trout meat was evaluated during storage at 4°C. Chemical and microbial assays were performed on rainbow trout fillets with alginate and chitosan coatings and 0.2% concentration of test essential oils. The results showed that the alginate coating with essential oils significantly decreased production of thiobarbituric acid (TBA) and total volatile basic nitrogen (TVBN) and reduced the growth of foodborne spoilage bacteria during storage at 4ºC. At day 12, the best results were obtained in chitosan coating + Z. multiflora, with 5.96 ± 0.12, 4.93 ± 0.12, and 3.83 ± 0.2 for total viable counts, psychrotrophic bacterial count, and lactic acid bacteria count, respectively. Moreover, the lowest amounts of chemical analysis were observed in chitosan coating + Z. multiflora at the final day (0.54 ± 0.03 and 20.31 ± 0.1 for TBA and TVBN, respectively). Our study revealed that essential oils can be used as effective natural components against undesirable chemical and microbial reactions in fish meat.     

Effects on Lipid Oxidation and Bioactive Properties of Rainbow Trout Fillets Fed with Barley

Barley concentrations ranging from 0% to 32% were incorporated into rainbow trout (Oncorhynchus mykiss) diets. The effect of barley concentration on lipid peroxidation and antioxidant activity of fish fillets were analyzed. Results showed that the inclusion of barley in rainbow trout diets had an inhibitory effect on lipid oxidation, probably associated with certain bioactive compounds in barley that could interact with scavenging and reducing metabolites involved in lipid oxidation. Concentrations up to 8% of barley produced fish fillets with high antioxidant activity and higher levels of alpha-tocopherol.     

Effects of Microbial Phytase Supplementation in Corn Distiller's Dried Grain with Solubles on Nutrient Digestibility and Growth Performance of Rainbow Trout,Oncorhynchus mykiss

Abstract

Two experiments were conducted to evaluate the effects of microbial phytase in corn distiller's dried grain with solubles (DDGS) on apparent digestibility coefficients (ADCs) and growth performance of rainbow trout, Oncorhynchus mykiss. In experiment 1, DDGS was supplemented with phytase at 0,300,600,900, and 1200 FTU/kg diet. A total of 180 fish (129.1±9.3 g) were stocked into six 140-L tanks with 30 fish/tank. Fish were assigned randomly to a reference diet and each of the 5 diets containing DDGS. Yttrium oxide was used as an inert marker. Results showed that ADCs in DDGS supplemented with different dosages of phytase were: dry matter, 49.1-58.6%; crude fat, 78.9-88.9%; crude protein, 80.0-91.9%; gross energy, 50.5-66.6%; minerals, -7.3-99.7%; and amino acids: 73.9 to 96.8%. In experiment 2, abasal diet containing 15% DDGS supplemented with lysine and methionine was used to determine if trace mineral supplemental levels in rainbow trout diets could be reduced if microbial phytase was supplemented. Six diets were made with trace mineral premix supplementation at 0.1, 0.08, 0.06, 0.04, 0.02, and 0%. Phytase was not supplemented in the basal diet, but supplemented at 500 FTU/kg diet in all other diets. Ten-week results showed that there were no significant differences in fish weight gain, feed conversion ratio, and survival (P < 0.05). There were no significant differences in fish body composition and apparent nutrient retention among fish fed all diets, except that fish fed a diet without trace mineral supplementation had the lowest zinc level and the highest manganese retention. Results indicated that phytase was effective in releasing most of minerals, and that trace mineral supplementation level could be reduced when phytase was used in rainbow trout diets.     

The effects of phase‐feeding rainbow trout (Oncorhynchus mykiss) with canola oil and Alaskan pollock fish oil on fillet fatty acid composition and sensory attributes

Rainbow trout (186 g) were fed three test diets where the lipid source (150 g kg^?1) was either menhaden oil (MO), pollock oil (PO) or canola oil (CO) for eight weeks to an average weight of 370 g. The CO group was then divided into two groups, one continuing on the CO diet and the other switched to the PO diet (CO–PO). After nine additional weeks of feeding, the average fish weight approximately doubled (719–749 g). No significant differences were found in average final weight or fillet yield among dietary treatment groups. Fatty acid profiles of fillets from trout fed MO, PO or CO‐supplemented diets reflected the fatty acid profiles of the added oils, whereas the fatty acid profile of fillet from trout in the CO–PO group exhibited values similar to those of fish fed PO. The ratio of ω3 : ω6 FA was nearly 2.5 times higher in fillets from the CO–PO group compared to the CO group. Sensory analysis showed that panelists preferred CO‐fed fillets over those fed MO, PO, or CO–PO. Phase‐feeding CO and PO reduced fish oil use and resulted in fillets with double the content of Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) over CO‐fed fish, similar to levels in MO‐fed fish.