FLAVOURING

Abstract: The present invention relates to a method of altering the flavour of farmed fish meat. Specifically, the invention provides a fish food, which is produced by a novel method wherein incorporation of a flavouring is incorporated into the feed along with the standard feed components. When this feed is subsequently fed to the fish, it results in an alteration of the flavour of the fish. In particular the present invention discloses the use of caraway oil, rosemary, lemon oil and garlic oil are especially effective at influencing the flavour of fish, once they have been added to the feed.

Description: FLAVOURING This invention relates to a method of altering the flavour of fish meat. Specifically the process relates to the improvement of fish flavour through the addition of flavourings to the feed composition. This method allows the flavour of farmed fish such as salmon, rainbow trout, brown trout and the like to be tailored for different consumer markets which in turn can lead to an increase in consumer choice through the incorporation of different flavours. The alteration of the flavour in the fish meat is brought about through the addition of different ingredients to the feed, which when taken up during the digestive processes, leads to them becoming incorporated in the fish meat with a resultant change in fish flavour. European Patent Application No 635217A sets out a method for modifying the characteristics of meat and fat to be obtained from livestock and poultry comprising feeding the livestock and poultry with spices. The active ingredients of the spice are taken into the body and transferred to internal fat thereby modifying the characteristics of the meat and improving the smell of the fat. Further, European Patent Application No 303764A provided a process for improving the flavour of hens ' eggs through feeding hens a mixed feed containing essential oils. Japanese Patent Application No 2207758A incorporated crude plant essential oils into feed composition for fish culture to prevent infectious disease of fish and inhibition of proliferation of pathogenic micro- organisms. Also, Japanese Patent Application No 10229830A relates to the incorporation of spices into fish feed to prevent a reduction in the flavour and taste of fish meat due to the deterioration of freshness over a short period of time and suppression of colour variation of dark coloured fish. None of the previous Patent disclosures provide a method of altering the flavour of fish through the manipulation and alteration of feed ingredients. It is an object of the present invention to provide a method of altering the flavour of fish by use of flavouring compounds. A further object of the present invention is to provide fish feed which results in an alteration of the flavour of the fish. According to the present invention there is provided a method of manuf cturing fish feed to alter the flavour of fish, the method comprising mixing feed components and adding a flavouring, characterised in that feeding of the fish feed to fish results in an alteration of the flavour of the fish. Preferably the flavouring ingredient is selected from the group consisting of; dibromophenol , smoke aroma, mussel extract, horseradish powder, juniper berry, olive, blackcurrant, walnut or the like. More preferably the flavouring ingredient will be selected from the group comprising; caraway oil, lemon oil, rosemary, garlic powder, lemon and garlic combination or the like. Further, a method of altering the flavour of fish is provided, comprising the steps of modifying a fish feed by means of the incorporation of a desired flavouring agent into a fish feed and feeding said fish with the feed. Preferably the fish are fed with said modified feed for a period of at least two weeks. Alternatively, the fish are fed with said modified feed for a period of at least one month. Preferably the flavouring ingredient is selected from the group consisting of; dibromophenol, smoke aroma, mussel extract, horseradish powder, juniper berry, olive, blackcurrant, walnut or the like. Preferably the flavouring ingredients will be added to the fish feed individually. There is further provided a fish feed for use in flavouring fish, the feed comprising feed components and a flavouring which results in an alteration of the flavour of the fish. Preferably, the fish feed contains a flavouring wherein this flavouring ingredient is selected from the group comprising; dibromophenol, smoke aroma, mussel extract, horseradish powder and juniper berry, olive, blackcurrant, walnut or the like. More preferably the flavouring ingredient will be selected from the group comprising; caraway oil, lemon oil, rosemary, garlic powder, lemon and garlic combination or the like. When the flavouring ingredient is lemon oil, an apparent improvement in fish texture is observed. This may also be achieved with other flavouring ingredients. From the tests described and results set out herein it is clear that a change in fish meat flavour can be brought about through alteration of the ingredients of the feed. It is of special significance and interest that the feeding of fish for a time period of less than one month can result in a significant effect on the significant effect on the fish meat flavour. It should also be noted that there seems to be an apparent improvement in the texture of the fish meat, this being exemplified by the fish examined in the first trial wherein lemon oil was added to the feed. Generally, fish feeds are composed of two main components; a meal component and an oil component. A thorough investigation was carried out into the addition of ingredients to the food, such that an alteration of fish flavour could be achieved. These investigations are detailed in the trials shown below. The results obtained from the experimentation are further detailed in the figures wherein; Figure 1 shows a graphical plot of all diets in respect of all 18 of the attributes tested on samples in Trial 1, Figure 2 shows a two dimensional scatter plot showing the principal component analysis (PCA) on fish from Trial 1 which have been fed seven diets, Figure 3 shows a two dimensional scatter plot showing principal component analysis (PCA) on individual fish samples, and Figure 4 shows a graph detailing the chemical analysis showing volatiles from fish which have been fed with different flavouring ingredients. Trial 1 This trial studied the incorporation of flavour ingredients into fish feed to manipulate the taste of the fish. Detailed sensory and technical analysis was carried out in this experiment to look at volatile compounds, as the sensory properties of fish flavour are mostly based on volatile components in different concentrations. Chemical and sensory analysis were performed on fish from the dietary groups. Atlantic salmon ( Salmo salar) were fed on one of the following seven different diets comprising standard fish feed with added flavouring compounds: Diet 289: normal control diet Diet 290 0.005g 2 , 6-dibromphenol added to lKg feed Diet 291 0.5g caraway oil added to lKg feed Diet 292 1. Og lemon oil added to lKg feed Diet 293 0.5g smoke aroma added to lKg feed Diet 294 0.5g rosemary extract to lKg feed Diet 295 10. Og freeze-dried minced shellfish (Mytilus edulis) added to lKg feed The fish were fed for a period of eight weeks. At the end of this period, the fish were slaughtered according to standard procedure. The fish were gutted and iced 4 days before analysis. Sensory Analysis The sensory analysis was performed as a standard flavour profile method (Qualitative-Descriptive- Analysis, ISO 6564:1985) using 12 trained assessors. Prior to the analysis, the sensory panel was calibrated on the chosen attributes and the intensity of the attributes. The attributes chosen for the describing test for odour were: Salmon odour, acidic odour, sea odour, caraway odour, rosemary odour, smoke odour and shellfish odour. The attributes chosen for the describing test for flavour were: Salmon flavour, acidic flavour, sea flavour, caraway flavour, rosemary flavour, smoke flavour, shellfish flavour and bitter flavour. Colour attributes were chosen as whiteness, hue and intensity. The fish was served as 15 millimetre thick cutlets, one for each assessor. Each sample was vacuumed in plastic bags before heat treatment in a water bath at 75 °C for 30 minutes. The samples were served randomly according to diet treatment, fish number and assessor. Each assessor was always given the cutlet taken from the same position of the fish fillet. Each assessor evaluated the samples at individual speed on a computerised system for direct recording of data (Compusense, Canada) using a continuous scale, where the left side of the scale indicated no intensity, and the right side indicated high intensity. The computer transformed the responses into numbers from 1.0 (no intensity) to 10 (high intensity) . Chemical analysis Volatile compounds. This evaluation was carried out on the basis that sensory properties of fish flavour are mostly based on volatile components in different concentrations and as such this part of the experiment served to identify these. Homogenised fish (25g) from the same batch that the sensory panel tested were mixed with 100ml of distilled water in a sealed erlenmeyer and heated to 70 °C for 10 minutes before lOOml/min nitrogen was flushed through the slurry for 20 minutes. Volatile compounds were absorbed on Tenax GR. Absorbed volatiles were injected by a Perkin Elmer ATD-400, into a HP5890-HP5970 GC-MSD system. Unknown volatiles were identified by means of a Wiley MS library search. Sensory Analysis No differences in colour attributes were observed. Fish from diet group 294 (rosemary) , were significantly different on 11 attributes from fish given other diets. Further, fish from this group also had a higher intensity of rosemary odour and flavour and were more bitter than fish given diets 289, 290, 291, 293 and 295 . Fish from diet group 294 had a lower level of salmon odour, acidic acid odour, sea odour, salmon flavour, acidic flavour and a higher level of rosemary odour and flavour. Fish from diet group 293 (smoke) , were more intense in salmon flavour than 292, and less intense in bitter flavour than 292. The PCA scatter plots shown in Figures 2 and 3 can be used in interpret the results and explain 100% of the variation. Figure 2 separates the samples mainly by odour and flavour of rosemary in comparison with odour and flavour of salmon, sea and acidic. This explains 97% of the variation. Diet 294 is described as the single diet with rosemary flavour/odour. Figure 2 (explaining the other 3% of the variation) is described by caraway and bitter flavour. Fish feed with diet 292 and diet 291 are found in that part of the plot. Fish fed with diets 295, 293, 290 and 289 are grouped very near each other. Table 1 shows the analysis of Tukey' s test on fish fed 7 diets. The fish fed the different diets were significantly different (P<0.05) for 12 of the 18 analysed attributes: salmon odour, acidic odour, sea odour, rosemary odour, shellfish odour, salmon flavour, acidic flavour, sea flavour, caraway flavour, rosemary flavour, shellfish flavour and bitter flavour. Fish number 305 from Diet 294 may be an outlier. An outlier is an object that is so different statistically from the other objects in the same class, that there is a possibility that the object does not belong to that class. It is proposed that the fish which is an outlier has been exchanged during handling or packaging. Statistical analysis was performed with and without this fish. Fish fed with diet 294 had less salmon odour, acidic odour, sea odour, salmon flavour, acidic flavour and more rosemary odour and flavour, bitter flavour than fish fed with other diets. There were also more differences between diet groups for rosemary odour and flavour. Figure 1 shows a graphical plot of all diets for all attributes (sample 305 included) . The plot gives a visual picture of the results. Figure 2 shows a two dimensional scatter plot showing Principal Component Analysis (PCA) on fish fed with the 7 diets (sample 305 included) . Figure 3 is a two dimensional scatter plot showing Principal Component Analysis (PCA) on individual Fish Samples (sample 305 included) . The differences between individual samples of fish in each diet group are shown in this plot. As previously mentioned, fish number 305 in diet group 294 differs considerably from the others in that diet. Dynamic analysis showed significant differences on rosemary, lemon and caraway flavourings. These were significantly different from each other and from the other four flavours. These results are tabulated in Table 2 and shown graphically in Figure 4. In particular, the graphical representation of these results shows clearly the difference in intensity of the lemon, caraway and rosemary flavourings. The main components found are based on terpenoid structures. These molecules have a hydrophobic structure. An improvement in texture of fish with flavourings was also observed, particularly with lemon oil. Trial 2 This further trial was based on results from Trial 1 and further analysed the ingredients which had shown some of the most effective results from Trial 1. In addition to these some new ingredients were also investigated, these being: Garlic powder, horseradish powder and juniper berry. These ingredients were added to the feed in two levels. Analysis of the results by sensory evaluation and characterisation revealed clear differences between the fish groups depending on which flavouring ingredient was added. It was determined that the effects on fish flavour were mediated by all the flavourings added in Trial 2, but that the addition of the garlic powder and the lemon oil ingredients had the greatest effects on overall flavour. Additional evaluation and determination of effectiveness was carried out by testing the fish in raw, cooked and smoked conditions. It should be noted that the flavour differences continued to be detected in all three of the aforementioned preparations. The flavour differences were also maintained during storage on ice. The flavour which resulted from the incorporation of the lemon oil ingredient into the diet was the most preferable. Trial 3 The third experiment was performed to study both the effect of combining flavour ingredients and to see how quickly the flavour was incorporated from the feed into the flesh of the fish. Four flavour ingredients were used: olive, blackcurrant, walnut and a combination of lemon and garlic. Atlantic salmon were fed the diets for periods of three and six weeks respectively. After three weeks of feeding the sensory panel evaluated that 18 of 24 sensory attributes of the fish flesh were significantly different. After six weeks 24 of the 28 sensory attributes were found to be different. The most significant differences were found in the flesh of the fish fed the diet where lemon and garlic were combined. Conclusion It has been shown that it is possible to manipulate the taste of fish by incorporating flavour compounds in the fish feed. The trials have shown that the addition of rosemary, caraway and lemon to feed resulted in good incorporation of flavour into the fish . Further, the results from Trials 2 and 3, indicate that the incorporation of garlic powder into the fish feed also has a significant effect on overall fish flavour, and that a combination of flavour ingredients can also result in an alteration of fish flavour. Further, Trial 3 indicates that the incorporation of flavour into the flesh from the diet can be done within a short period of time.

Claims: 00/59316 14 CLAIMS 1. A method of manufacturing fish feed to alter flavour of fish, the method comprising mixing feed components and adding a flavouring, characterised in that feeding of the fish feed to fish results in an alteration of the flavour of the fish. 2. A method as claimed in claim 1 wherein the fish feed also results in an alteration in the texture of the fish. 3. A flavouring for use in the method of claim 1 or 2 wherein said flavouring ingredient is selected from the group comprising: dibromophenol, smoke aroma, mussel extract, horseradish powder and juniper berry, olive, blackcurrant, nut or the like. 4. A flavouring for use in the method of claim 1 or 2 wherein the flavouring ingredient is selected from the group comprising: caraway oil, lemon oil, rosemary and garlic powder, lemon and garlic combination or the like. 5. A method of altering the flavour of fish comprising the steps of modifying a fish feed by means of the incorporation of a desired flavouring agent into a fish feed and feeding said fish with the feed. 6. A method as claimed in claim 5 which also alters the texture of the fish. 7. The method of claim 6, wherein fish are fed with said modified feed for a period of at least two weeks . 8. The method of any of claims 5 to 7, wherein fish are fed with said modified feed for a period of at least one month. 9. A flavouring for use in the method of any of claims 5 to 8 wherein said flavouring ingredient is selected from the group comprising: dibromophenol, smoke aroma, mussel extract, horseradish powder and juniper berry, or the like. 10. The method of any of claims 5 to 8 wherein the flavouring ingredient is be selected from the group comprising: caraway oil, lemon oil, rosemary and garlic powder, or the like. 11. The method of any of claims 5 to 10 wherein the flavouring ingredients will be added to the fish feed individually. 12. A fish feed for use in flavouring fish meat, the feed comprising feed components and a flavouring which results in an alteration of the flavour of the fish. 13. A fish feed as claimed in claim 12 for use altering the texture of fish. 14. A flavouring for use in the feed of claim 12 wherein said flavouring ingredient is selected from the group comprising: dibromophenol, smoke aroma, mussel extract, horseradish powder and juniper berry, olive, blackcurrant, nut or the like.

Inventors: NILSSON ASTRID, ROERA ANNA MARIE BENCZE, SLINNING KARL-ERIK, SOLBAKKEN ROAR, THOMASSEN MAGNY SKINLO, VOGT GJERMUND, NILSSON, ASTRID, ROERA, ANNA, MARIE, BENCZE, SLINNING, KARL-ERIK, SOLBAKKEN, ROAR, THOMASSEN, MAGNY, SKINLO, VOGT, GJERMUND
Applicants: EWOS LTD, NILSSON ASTRID, ROERA ANNA MARIE BENCZE, SLINNING KARL ERIK, SOLBAKKEN ROAR, THOMASSEN MAGNY SKINLO, VOGT GJERMUND, EWOS LIMITED, NILSSON, ASTRID, ROERA, ANNA, MARIE, BENCZE, SLINNING, KARL-ERIK, SOLBAKKEN, ROAR, THOMASSEN, MAGNY, SKINLO, VOGT, GJERMUND
Application year: 2000
Main classification: A23K1
IPC codes: A23K1