WO2008147214A1

WO2008147214A1 - Food article with improved shelf life

Info

Publication number: WO2008147214A1
Application number: PCT/NO2008/000189
Authority: WO
Inventors: Harald Wærsted TAKLE; Turid MØRKØRE
Original assignee: NOFIMA AKVAFORSK-FISKERIFORSKNING AS
Current assignee: NOFIMA AKVAFORSK-FISKERIFORSKNING AS
Priority date: 2007-05-29
Filing date: 2008-05-29
Publication date: 2008-12-04
Anticipated expiration: 2009-11-29

Abstract

Food and food products containing fats and oils, with prolonged shelf life with respect to rancidity are provided. Also freeze stored food and food products with improved quality with respect to liquid holding capacity and colour are provided. Further the present invention comprises a composition for treatment of food and food products and a method for the manufacturing of the aforementioned foods and food products.

Description

Food article with improved shelf life

Field of invention

The present invention relates to food articles with improved shelf life and method for preparation of the same. Within the scope of the present invention are also stored food articles with improved quality.

Background of invention

A problem in storage of foods and food products is rancidity, particularly in fish and meat that contain lipids with high content of polyunsaturated fatty acids.

The rancidity reduces the quality of the foods and food products by deteriorating the sensory perception - particularly related to production of degradation components that alter the odour and flavour negatively.

The oxidation process where fat turns rancid may be inhibited or retarded by storage in an oxygen reduced atmosphere, e.g. by use of air tight/hermetical packaging or storage at low temperatures -18 to -25 °C. Foods and food products stored under freezing conditions for an extended time may dry out. Another disadvantage with freezing is the loss of weight (mainly water) during thawing which makes the foods and food products less attractive both in taste i.e. moist/juiciness, texture and colour.

Fresh fish, frozen fish and fish products make up an important food source which is transported over considerable distances from the fishing grounds to the distribution network and finally to the consumers. The transportation distance for farmed fish from the fish abattoir to the consumer is also often considerable. To keep fish attractive and suitable as food when reaching the consumer it is kept on ice, frozen, super-chilled, chilled or preserved by other means e.gr salting during transportation and storage, MAP (Modified Atmosphere Packaging) or vacuum.

EP 0 209 509 discloses antioxidants, spermine and spermidine, for protection of oxidizable compounds such as polyunsaturated fatty acids against oxidation. The antioxidants are also disclosed having a growth stimulating effect in fish and may be used as an additive in feed, particularly for farmed fish.

There is a need for foods and food products containing lipids and fats that may be stored e.g. frozen, for an extended time, without initiation of rancid processes, colour changes or loosing weight when thawed. The content of unsaturated fatty acids in fish fats and oils is high, and are therefore particularly exposed to oxidation and rancidity. An increased consumption of fish is recommended because of the health benefits of fatty acid profile found in fish lipids. The demand for good quality fish is increasing and thus the need for such products with prolonged shelf life.

Summary of the invention

The invention is defined by the appended claims. Food and food products containing fats with prolonged shelf life with respect to rancidity are provided. Also freeze stored food and food products with improved quality with respect to liquid holding capacity and colour are provided. Further the present invention comprises a method for the manufacturing of the aforementioned foods and food products.

Brief description of the drawings

FIG. 1 discloses graphs showing the effect of spermine treatment on muscle colour of herring. A) Red (a* -value), and B) white (L*-value) colour was measured after bathing muscle samples (3 X 3 cm) to three different concentrations of spermine for 3 minutes (n= 3).

FIG. 2 discloses graphs showing the weight loss during thawing (4⁰C) of cod and herring muscle frozen at -20 °C for 3 x 7 days.

FIG. 3 shows TBARS analysed in raw and smoked salmon treated with different concentration of spermine. Bars with different superscript, differs significantly, p<0.05.

FIG. 4 shows TBARS analysed in ground beef and chicken-turkey forcemeat treated with different concentration of spermine. Bars with different superscript, differs significantly, p<0.05.

FIG. 5 discloses L* -value analysed in raw salmon treated with different concentration of spermine. Bars with different superscript, differs significantly, p<0.05.

Detailed description of the invention The polyamide spermine is a fat-soluble and water-soluble antioxidant with the following chemical structure;

NH NH₂

H₂N NH

Spermine Spermine is also known as gerontine, musculamine and neuridine.

By the term "fat fish" as used herein is meant a fish with a fillet fat content of 10% or above.

By the term "lean fish" as used herein is meant a fish with a fat content of 10% or below.

Oxidation of fatty acids, particularly unsaturated fatty acids, is a well known problem in storage of foods and food products. The oxidized fatty acids give the food or food product an unpleasant taste and odour of rancidity. Freezing may slow down the oxidation process; however, the extended shelf life is even though limited. Another problem occurs when the frozen food or food product is thawed. In the thawing process food and food products loose water and leave the food and food products dry and ductile with an undesirable texture.

In one aspect of the invention a food and food product is provided where spermine is used to inhibit the process wherein said food and food product are turned rancid i.e. the oxidation of fatty acids comprised in the food and food product. The food or food product in question is treated with a composition comprising spermine as disclosed below. The treatment with the spermine composition reduces the oxidation of fats and oils comprised in the food or food product considerably compared to untreated food or food product. The effect is strongest expressed in the food or food product comprising more fats and/or oils. In another aspect of the invention a frozen food and/or food product is provided where spermine is used to retain said food's and/or food product's weight i.e. water, during thawing. It has been found that food and/or food products treated with a spermine comprising composition retains its weight during thawing, and keeps the products moist and tender with a desirable texture.

During storage, freezing and handling the colour of the muscle (meat) often change and give the food or food product a less visually attractive. An aspect of the invention is to give food and food products treated with spermine a more attractive appearance.

In yet another aspect of the invention a composition comprising spermine is provided. The composition comprises spermine in an amount of from about 1 to about 2000 nM. In one preferred embodiment of the invention said composition comprise from about 10 to about 1000 nM spermine. The amount of spermine in the composition should be sufficient to provide the desired effects, without reducing the quality of the treated products by addition of undesirable smell or taste.

The spermine in the above described composition is dissolved in a suitable solvent e.g. water. The solvent has to be chosen as to be compatible with the food or food product to be treated.

In a further aspect of the invention a method for the manufacturing of a food or food product with extended shelf life and improved thawing properties is provided wherein said method comprises the step of treating the food or food product with a spermine comprising composition. The food or food product may be treated with the spermine composition by means of bath, spraying or injection or a combination thereof.

Spermine is an antioxidant and performs as a radical scavenger in the body. Food and food products comprising spermine would therefore in addition to the benefits mentioned above also have the health promoting property arising from the antioxidant nature of spermine. Hence, an aspect of the present invention comprises functional food comprising spermine as an antioxidant and/or radical scavenger in the body of the consumer.

The products according to the present invention have high commercial potential in both primary and secondary food production, and for long distance distribution of food articles all over the world.

The invention will now be illustrated by the following non-limiting examples.

EXAMPLES

Example 1 Rancidity experiment

Muscle (3 x 3 cm) from lean fish (farmed cod) and fat fish (captured herring) were exposed to aqueous solutions with different concentrations of spermine and for different exposure times (Table 1).

Table 1. Overview of the experiment

Analysis for fat%, anisidine number and peroxide number were performed. The analysis methods used were as follow; Fat% Bl&D: E.G.Bligh & WJ. Dyer : A rapid method of total lipid extraction and purification. Can.J.Biochem.Physiol. VoI 37 (1959), Anisidine number; AOCS Cd 18-90 and Peroxide number; AOCS Cd 8b- 90). The anisidine number describes the degree of oxidation i.e. oxidative rancidity, by determining the amount of carbonyl compounds formed when peroxides decompose. This gives a measure on secondary oxidation products. This is the most important unity for measuring rancidity, since carbonyl compounds often have strong smell and taste even in very low concentrations. Peroxide number describes the amount peroxides formed and thereby detect the degree of oxidative rancidity. In contrast to the anisidine number this is not related to the quality of the product. The results of the anisidine number and the peroxide number are given in tables 2 and 3, respectively. The fat % in cod was 0.8 % while the fat % in herring varied between 12 % and 16 %. Additional sensory tests, pH analysis and fish filet firmness. None of these tests gave any evident results. Table 2. Anisidine number

The results show that the anisidine number for herring is reduced by a factor of 2.5 after 3 minutes water bath added spermine. No corresponding effect was observed with the cod treated in the same manner.

Example 2

Colorimetric analyses The muscle samples were subjected to image analyses in order to examine flesh colour. Interpretation of the results was performed by transforming the image data according to the tristimulus system: L*, a*, b*.

Table 4. Red colour (a* -value) in herring muscle.

Spermine Herring nM Exposure time

3' 30' 180'

0 7.4±0.1 5.7±0.3 6.0±1.4

300 5.6±0.3 5.4±1.6 4.3±0.5

900 4.6±1.7 6.6±0.5 6.0±0.5 Table 5. White colour (L*-value) in herring muscle.

Spermine Herring nM Exposure time

3' 30' 180'

0 47.8±2.9 48.2±3. 5 51.1±1 .9

300 51.2±4.3 46.8±1. 0 52.3±2 .6

900 49.0±0.4 48.9±4. 1 47.2±2 .6

The results, presented in tables 4 and 5, showed that spermine bathing of herring muscle gives a significant reduction in red (a* -value) colour. The most positive effect was found when herring muscle was bathed in the 900 nM spermine solution for 3 minutes, shown by a 38% reduction in red colour. Correspondingly, this treatment had a positive but insignificant effect on white colour (L*-value). Figure 1 shows the effect of spermine treatment on muscle colour of herring.

A) Red (a* -value), and B) white (L* -value) colour was measured after bathing muscle samples (3 X 3 cm) to three different concentrations of spermine for 3 minutes (n= 3).

Example 3

Liquid holding capacity

Liquid holding capacity was analysed as gravity drip during 3 days of cold storage at 3⁰C (modified according to Mørkøre et al., "Composition, Liquid Leakage, and Mechanical Properties of Farmed Rainbow Trout: Variation Between Fillet Sections and the Impact of Ice and Frozen Storage", Journal of Food Science, vol. 67, no.5, 2002) and as weight loss after freezing/thawing as compared with raw muscle (reference is made to Mørkøre et al. "Impact of dietry oil source on product quality of framed Atlantic cod, Gadus morhua". Aquaculture, 2007). The samples were frozen in sealed plastic bags at -2O⁰C for seven days before they were thawed at 4⁰C overnight. Thereafter the muscle samples were exposed to day light and room temperature for three hours. This treatment was repeated three times in order to trigger lipid oxidation before the muscle samples were weighed and weight loss during freezing and thawing was calculated [initial muscle weight - final muscle weight (after 3 x freezing and thawing) / initial muscle weight x 100%].

Liquid loss during cold storage showed no significant variation between treatments. On the other hand, there were significant differences in liquid holding capacity during freezing / thawing. Obviously it is an advantage that the muscle retains as much liquid as possible during freezing / thawing. High losses give decreased product yield, and significantly reduce juiciness, taste and texture. The treatment that showed significantly improved liquid holding capacity was "Treatment B" (Fig. 2). This treatment (3 min exposure in 300 nM spermine) gave best results both for herring and cod.

Figure 2 shows the weight loss during thawing (4⁰C) of cod and herring muscle frozen at -20 ⁰C for 3x7 days. Prior to freezing the muscle was exposed to aqueous solutions with different concentrations of spermine (0, 300 and 900 nM) and for different times (3, 30 and 300 minutes). Definition of abbreviations is given in Table 1. Error bars indicate standard error between samples within treatment.

Example 4

The following food products 1. raw salmon (fat) 2. smoked salmon, 3. ground beef, and 4. chicken/turkey forcemeat, were subjected to spermine treatment and analysed with respect to colour and oxidation. Also freezing and thawing procedures were performed.

Datasheet for each food product

1. Raw salmon: The anterior fillet part of fresh 4kg farmed salmon (15% fat) was minced and subjected to treatment four days after slaughter.

2. Smoked salmon: The anterior fillet part of commercially smoked salmon, stored at 4°C for three weeks, was minced and subjected to treatment.

3. Ground beef: Ingredients: Cattle meat. Nutritional content per 10Og: Energy 870 KJ/196 kcal, 17g protein, Og carbohydrate, 14g fat. Parts of the product had been frozen. Date of packing: 16.11.07. Best before: 30.11.07. All information according to the manufacturers labelling.

4. Chicken/turkey, forcemeat: Ingredients: Chicken (50%), Turkey (49%) and salt. Nutritional content per 10Og: Energy 602 KJ/144 kcal, 19, 5g protein, <0,lg carbohydrates, 7.3g fat. Date of packing: not accessible. Best before: 28.11.07. All information according to the manufacturers labelling.

In table 6 an overview of the treatments of each of the above mentioned food products are given.

Table 6. Overview of treatments given to each food product No Treatment

Control Added 25ml water per lOOg minced meat 100OnM Added 25 ml 1000 nM spermine per lOOg mince meat 200OnM Added 25 ml 2000 nM spermine per lOOg minced meat Preparation of Spermine solutions:

2000 nM ; Dissolved 0,202g spermine in 500ml distilled water 1000 nM ; Prepared IM solution: 0,202g/ml spermine and used 500ul IM till 500ml distilled water

The spermine powder was weighed in at dark, and the bottles were covered with aluminium folium.

Procedure for testing of the food additive

2 kg of each food product were mixed using a food processor and then 400 gram minced meat were divided in separate glass vials that were added each concentration of spermine or distilled water. Thereafter 100 g minced meat was divided into plastic bags, each containing 2Og minced meat. The samples were stored in darkness at -20⁰C for five months.

Analyses conducted: Colour analyses: Colour analyses were performed using a Minolta Chroma Meter II-CR200 (Minolta, Osaka, Japan). The lightness (L*-value) was recorded according to the CIE (1976) (Wyszecki and Stiles, 1967, Colour Science. Wiley, New York, p. 628.)

Oxidation products (Rancidity level): Analyses of thiobarbituric acid reactive substances (TBARS) were analysed according to a method by [Miller, 1998. Food Chemistry, A laboratory manual. Wiley Interscience, New York, USA.

Freezing and thawing procedures After five months, the samples were exposed to three thawing/freezing cycles as described in detail in example 3 above.

The results showed that spermine treatment reduces rancidity in sea- and land-living animals, and raw and value-added products (Fig. 3 and 4). The results were most pronounced in salmon and ground meat, which have higher fat content. The relative high individual variation is due to the low amount of oxidative products in the chicken-turkey forcemeat (7.3% vs 14-15%).

Filet colour is the most important quality trait in farmed salmon. Thus, salmon with light colour are not suitable as high value products. Measurements of filet lightness show that spermine gave improved filet colouration (Fig. 5). Spermine treatment of sea and terrestrial food gave significantly reduced rancidity, improved colour and increased water holding capacity. No negative effects on quality were found. Treatment with spermine improve both shelf-life, sensory and technological qualities. It is well documented that freshness and filet colour are the most important trait influencing consumers choice, while water binding capacity improves the yield and sensory juiciness of the product.

Claims

1. Food or food product comprising fats and/or oils which has been treated with a spermine comprising composition.

2. The food or food product according to claim 1 wherein said food or food product is animal products.

3. The food or food product according to claim 2 wherein said animal products comprising fat.

4. The food or food product according to claims 2 or 3 wherein said animal products is stored.

5. The food or food product according to claim 1 wherein said food or food product has radical scavenger properties in the body of the consumer.

6. A spermine composition which comprises from about 1 to about 2000 nM spermine.

7. The composition according to claim 6 which comprise from about 10 to about 1000 nM spermine.

8. A method for the manufacturing of a storage stable food or food product containing fats comprising the step of treating said food or food product with a composition comprising spermine.

9. The method according to claim 8, wherein said composition comprises from about 1 to about 2000 nM spermine.

10. The method according to claim 9, wherein said composition comprises from about 10 to about 1000 nM spermine.

11. The method according to claims 8-10 wherein the treatment with said spermine composition is performed by bath, spraying or injection.