METHOD FOR THE PRODUCTION OF A STABLE FRUIT PREPARATION

Abstract

Disclosed is a method for the production of a stable fruit preparation comprising the steps of addition of active pectinmethylesterase (PME) to a fruit preparation to perform an enzymation step on the fruit preparation, followed by inactivation of PME in the fruit preparation to obtain a stable fruit preparation, wherein gelation is prevented or at least significantly reduced during the presence of active PME in the fruit preparation by applying mechanical stress to the fruit preparation comprising active PME.

Claims

1. Method for the production of a stable fruit preparation comprising the steps of addition of active pectinmethylesterase (PME) to a fruit preparation to perform an enzymation step on the fruit preparation, followed by inactivation of PME in the fruit preparation to obtain a stable fruit preparation, wherein gelation is prevented or at least significantly reduced during the presence of active PME in the fruit preparation by applying mechanical stress to the fruit preparation comprising active PME, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 1 Bostwick unit in, wherein the Bostwick units are measured according to the standard ASTMF1080-93, including equilibration of the samples at 20° C. with an additional agitation with a propeller stirrer for 25 sec at 25 rpm, and wherein the reduction of Bostwick units is the reduction compared to the fruit preparation without enzymation and also compared with the enzymated food preparation, which is not exposed to a mechanical stress during enzymation; and wherein a mechanical stress of 1 to 100 Pa is applied to the fruit preparation containing active PME by stirring, shaking, pumping or combinations thereof.

2. Method according to claim 1, wherein the fruit preparation is a puree.

3. Method according to claim 2, wherein the puree or the fruit used for the fruit preparation is subjected to heat treatment prior the enzymation step.

4. Method according to claim 3, wherein the heat treatment is performed at temperatures from 60 to 110° C.

5. Method according to claim 3, wherein the heat treatment is performed for a duration of 30 seconds to 30 minutes.

6. Method according to claim 1, wherein a mechanical stress of 3 to 20 Pa, is applied to the fruit preparation containing active PME by stirring, shaking, pumping or combinations thereof.

7. Method according to claim 1, wherein the fruit preparation is a preparation selected from strawberry (Fragaria ananassa), peach (Prunus persica), apricot (Prunus armeniaca), fig (Ficus carica), pear (Pyrus), sour cherry (Prunus cerasus), cherry (Prunus avium), apple (Pyrus malus, Malus pumila), blueberry (Vaccinium cyanococcus), mango (Mangifera indica), banana (Musa acuminata); or mixtures thereof.

8. Method according to claim 1, wherein the fruit preparation contains fruit pieces, or whole fruits.

9. (canceled)

10. Method according to claim 1, wherein the stable fruit preparation consists of fruits in the form of fruit puree, fruit juice, fruit pieces, or mixtures thereof and inactivated PME.

11. (canceled)

12. Method according to claim 1, wherein no Ca.sup.2+ ions are added during production.

13. (canceled)

14. Method according to claim 1, wherein the stable fruit preparation is packaged into a storage-stable form.

15. Method according to claim 1, wherein the method further comprises a fruit heating step before addition of PME to the fruit preparation and a heating step after the enzymatic treatment with PME, wherein mechanical stress is also applied in the course of the heating step.

16. Method according to claim 1, wherein the enzymation step is performed for a duration of 1 to 120 min.

17. (canceled)

18. Method according to claim 1, wherein the enzymation step is performed under stirring of 10 to 500 rpm.

19. (canceled)

20. Method according to claim 1, wherein the method further comprises a pasteurizing step with a duration of at least 1 min.

21. Method according to claim 1, wherein the method further comprises a fruit heating step before addition of PME to the fruit preparation of at least 50° C.

22. (canceled)

23. Method according to claim 1, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 2.

24. Method according to claim 1, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 5.

25. Method according to claim 1, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 20%.

26. Method according to claim 1, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 40%.

Description

[0042] The present invention is further illustrated by the following examples and the figures, yet without being limited thereto.

[0043] FIG. 1 shows an example of a rheology curve in a 4-step trial (x-axis: time [s], y-axis: Storage Modulus G′ [Pa], Loss Modulus G″ [Pa]);

[0044] FIG. 2 shows the gel development during the enzymation and reversibility of strawberry gels at two different shear rates applied (x-axis: time [s], y-axis: Storage Modulus G′ [Pa], Loss Modulus G″ [Pa]); 0.1% of shear strain corresponds to 0.5 Pa of shear stress, 0.5% of shear strain corresponds to 1 Pa shear stress;

[0045] FIG. 3 shows the influence of shear during enzymation on resulting values of elasticity and loss moduli after application of high shear, i.e. the effect of different shear stress [Pa] during enzymation step (x axis) on the values of G′ and G″ [Pa]after high-shear treatment (y axis).

EXAMPLES

Example 1: Fruit Preparations of Strawberry, Banana and Peach

Model Recipe

[0046] Fruit puree—50% [0047] Sugar—50% [0048] (Fungal PME—0.05%)

[0049] Model recipes (1 kg sample) having only fruit puree and sugar were cooked with or without pre-heating step and with or without agitation during enzymation step. The cooking was done in lab in Miniterm Ecotherm F water bath (Dinkelberg Analytics). The samples were agitated at 40 rpm.

[0050] Strawberry and peach purees were produced from IQF fruit (not heat-treated before) and then part of the puree was additionally heated at 90° C. for 10 minutes. For Banana aseptic puree was used, still some effect of heat-treatment can be seen.

[0051] Enzymation was done at 40° C. for 10 minutes.

TABLE-US-00001 Strawberry Banana Peach Control (no enzymation) 24 13 18 No agitation, no pre-heating 18 8 14 Agitation, no pre-heating 12 6 8 No agitation, pre-heating  9* 7 9 Agitation, pre-heating   7.5 5 5

[0052] In another set-up, fruit preparations of apricot, pear and apple are provided with 50% fruit puree and 50% sugar Here, the effects of agitation and puree pasteurization were not studied separately. The consistency measurements (Bostwick flowabilities) for the fruit preparations according to the present invention (“Enzymation”) in comparison with the fruit preparations without the enzymation (“No enzymation”) step are as follows:

TABLE-US-00002 No enzymation Enzymation Apricot 10 5.5 Pear 18 5.2 Apple 15 3.5

[0053] Measured are Bostwick flowabilities for 60 seconds

[0054] The figures given in the tables are consistency figures measured in Bostwick units ([cm/min]) as determined in the end product. In short, this consistency was determined with a Bostwick consistometer (CSC Scientific Co., Fisher Scientific, Nepean, ON, Canada) to evaluate resistance to flow of the fruit preparations by the ASTM standard method (ASTM, 2019; Standard F1080-93). Before measuring the sample on Bostwick consistometer the samples were equilibrated at room temperature (20° C.) and additionally agitated (Heidolph, RZR 2102 propeller stirrer, 25 sec at 25 rpm). Flow on an inclined plane is caused by the effect of the gravitational force on the product. The flow distance depends on the viscosity but also on the elastic properties and adherence of the product to the surface of the consistometer. The spring-loaded gate was first closed so that the reservoir could be filled to the upper limit (75 mL), and then the gate was opened, instantaneously releasing the fruit preparation. The distance (in cm) that the fruit preparations travelled after 60 s was recorded. Triplicates were performed for each of the fruit preparations under analysis. The smaller the flow distance, the higher the consistency of the fruit preparation.

[0055] In case of every fruit a positive effect of both agitation and pre-treatment of puree can be observed.

Example 2: Mango Preparation with Fruit Ingredients Only

[0056] The cooking of 1 kg sample was done in lab in Miniterm water bath. [0057] Mango puree (pasteurized)—20% [0058] Mango cubes 9×9—55% [0059] Grape juice concentrate—24% [0060] Pectinmethylesterase—0.1% [0061] Water—0.9%

[0062] Mix all the ingredients except PME and heat to 40° C.

[0063] Add PME, then agitate the mixture for 10 minutes (in the lab at 40 rpm), then immediately heat to 85° C.

[0064] Pasteurize the mixture for 10 minutes at 85° C. and cool it under agitation to 30° C.

[0065] Fill the preparation into a container; store container in a cold room 8-15° C.

[0066] The preparation produced this way has Bostwick flowability 6.5 at 20° C. and is stable for at least the observation period of 56 days.

Example 3: Strawberry Preparation with Sugar

[0067] Strawberry—50% [0068] Sugar—25% [0069] Strawberry puree—25% [0070] Pectinmethylesterase (Aspergillus niger)—0.05%

[0071] Slowly add 200 kg of frozen whole strawberries to the cooking vessel containing 10-15 l of water.

[0072] Heat the fruits up to 65° C., then produce a puree.

[0073] Heat the resulting puree to 90° C. for 5 minutes

[0074] Add 200 kg of sugar

[0075] When the sugar is completely dissolved add 400 kg of 10×10 strawberry dices

[0076] Warm the mixture to 40° C. and add solution of PME enzyme

[0077] Agitate the mixture for 10 minutes at 16 rpm, then immediately heat to 85° C.

[0078] Pasteurize the mixture for 10 minutes at 85° C. and cool it under agitation to 30° C.

[0079] Fill the preparation into a 800 l container; store container in a cold room 8-15° C.

[0080] Mean shear rates during agitation step in production were ca. 10-20 s.sup.−1 (computer CFD simulation). Viscosity of fruit mixture during enzymation step was within range of 1000-2000 mPa*s this gives shear stress values of 10 to 40 Pa

[0081] The resulting strawberry fruit preparation was stable within 42 days. This example shows that upscaling the method from the present invention from the lab to industrial scale was successful.

Example 4: Model System Shear Stress

[0082] During laboratory tests and test on industrial line it was observed that no shear or low shear during enzymation leads to lower final viscosity. In the following experiments, shear stress was quantified in a series of rheometer trials.

Rheological Trial Method:

[0083] Enzymation was done at 20° C. (also based on handling reasons). Enzyme concentration was adjusted accordingly (increased from 0.1% to 0.2%). The model systems were chosen in the way that firm brittle gel is formed already after 10-12 minutes of enzymation but in the beginning the mixture is relatively liquid.

Production of Strawberry Recipe:

[0084] Strawberry puree from IQF fruits (70%) was mixed with sugar (30%) and pasteurized (so that the strawberry enzymes are deactivated) and then cooled down to ambient temperature. The preparation was sieved through a fine sieve (0.5 mm) to remove all the particles that can influence the measurement.

[0085] Amplitude sweep was measured in the model system before addition of enzyme as well as 10 minutes after addition of enzyme (as the measurement of full amplitude sweep takes time the first point was recorded 10 minutes after start of enzymation and the last point in ca. 15 minutes). With amplitude sweep measurement linear visco-elastic range of the product was found. For the kinetic trials a point (0.5% shear) was selected which was within the linear viscoelastic range. Kinetic tests were done according the following procedure: The enzyme was added, and the timer was started. After stirring for 15 seconds the sample was placed on rheometer (PP50 measuring system) and trimmed. Recording the curve has started exactly in 2 minutes from the enzyme addition.

[0086] The kinetic step without high shear included 1-2 steps.

[0087] Controlled pre-shear at fixed shear strain was applied (G′ and G″ were measured on modular compact rheometer MCR 302 at this shear, shear stress was also recorded by the rheometer)

[0088] 0.5% shear strain was applied for 5 minutes (G′, G″ and shear stress were recorded)

[0089] The kinetic test with shear included 3 of 4 steps. Step 2 was not done when the curve without high shear was recorded.

[0090] Controlled pre-shear at fixed shear strain was applied (G′ and G″ and, shear stress was also recorded by the rheometer)

[0091] 0.5% shear was applied for 1 minute (G′, G″ and shear stress were recorded)

[0092] High shear was applied for 20 seconds

[0093] Recovery of G′ and G″ (recorded at 0.5% shear strain) was monitored.

[0094] An example of a rheology curve in a 4 steps trial is depicted in FIG. 1.

[0095] Time change in step 3 from 20 seconds to 1 minute did not change the results, so the time was kept at 20 seconds. Shear-reversibility can be defined as the % of G′ or complex modulus G* lost after the shear was applied. However, during the present trial the enzyme remains active and continues to work. So, for more accurate measurement of shear-reversibility of the product the results of 2-step kinetic trial (no high shear) and 3-step trial (high shear applied) were compared or 4-step trial was used where approximation of the curve from step 2 with the recovery curve (step 4) was compared.

[0096] Amount of shear was modified by the different shear strain applied on step 1. However, it is also important how many measuring points were taken. If only once in 10 seconds was measured, the shear is lower. If every second was measured, the shear is higher. Shear stress is recorded automatically (it is directly related to torque) As the product thickens—shear stress also increases. Therefore, mean values of shear stress were used during the step 1. To study the effect of enzymation time only step 1 was increased, while other steps were kept the same.

Results:

[0097] It was observed that much more gel is developed initially when no shear is applied. But then this gel is not reversible once we apply high shear (see FIG. 2). We have studied gel development at different shear stresses applied. In strawberry recipe there is a big difference in reversibility and values of elasticity modulus when we increase shear stress from 0.5 to 3 Pa, however when the shear stress is further increased to 20 Pa increase in elasticity modulus is lower (FIG. 3). Accordingly, in this model system applying a shear stress of 0.5 Pa is an appropriate lower limit to obtain the advantageous effects according to the present invention. to the levels of shear, however, cannot be generalized as the fruit systems that we have studied have very different viscosities and yield stress values.

[0098] Further increase of shear stress (e.g. above 100 Pa) may lead to decomposition of other stabilizers naturally present in fruit purees, first of all native starches. High shear may also result in particle size reduction and loss of viscosity. Therefore, application of high shear doesn't provide additional benefits.

[0099] Obviously higher agitation increases the speed of enzymation reaction, so the observed effect may be also attributed to higher enzymation speed. However, before the high shear was applied the products that were strongly agitated didn't have higher viscosity than the products that were not agitated (weakly agitated). To further prove that the positive effect according to the present invention is due to texture modification by mechanical stress and not due to higher enzymation degree, additional trials with higher enzyme concentration and longer enzymation times were performed. In these trials, it was observed that increase of enzyme concentration or enzymation time did not improve shear reversibility of the products which were not agitated.

Methods Used

Measurement of Mechanical Stress [Pa]

[0100] Mechanical stress is measured in Pa by the method disclosed by Läuger et al. in the article “Discrepancies in the specified data and presentation of a new data set for NIST Standard Reference Material® SRM 2490” and was performed with a rheometer as disclosed therein (Physica MCR 501 Rheometer from Anton Paar (AT)) with Peltier temperature control.

Brix and pH Measurement

[0101] Brix and pH measurements are done using RX-5000 refractometer from Atago LTD (Japan) and pH-meter InoLab 730 WTW GmbH (Weilheim, Germany) respectively.

Viscosity Measurement

[0102] Viscosities of the purees were measured on Brookfield viscometer (spindle 3, 10 rpm). Final preparations were accessed on a Brookfield viscometer and on a Bostwick consistometer. In all cases the samples were equilibrated at room temperature. Before measuring the sample on the Bostwick consistometer the samples were additionally agitated (Heidolph, RZR 2102 propeller stirrer, 25 sec at 25 rpm) to ensure homogeneity.

[0103] Additional tests on viscoelastic properties were done on the modular compact rheometer MCR 302 (Anton Paar GmbH, Graz, Austria), which is temperature controlled with a Haake K20 and DC5 device (Haake, Karlsruhe, Germany). The plate-plate measuring system (PP50) was used. Results are collected using RheoCompass software. Temperature is always set to 20° C. and measurement starts after 2 min of temperature constancy. Tests are always done as duplicate.

[0104] To determine the viscoelastic properties of the substance, the amplitude gamma was logarithmically increased from 0.01 to 1000%. For interpreting the viscoelastic properties, the ratio between G′/G″ at an angular frequency of 10 l/s is taken to describe the strength of the strawberry fruit preparation.

Storage Stability

[0105] The products were kept in transparent containers (500 ml) for 2 months at +10° C. Floating of pieces and syneresis were noticed, however the exact amounts of liquid separated from the gel was not measured. Bostwick flowability at the end of shelf life was re-measured and compared to the value after 1 day. Acceptable difference for acknowledging presence of storage stability was <2 Bostwick units.

[0106] The present invention is further defined by the following embodiments: [0107] 1. Method for the production of a stable fruit preparation comprising the steps of addition of active pectinmethylesterase (PME) to a fruit preparation, followed by inactivation of PME in the fruit preparation to obtain a stable fruit preparation, wherein gelation is prevented or at least significantly reduced during the presence of active PME in the fruit preparation by applying mechanical stress to the fruit preparation comprising active PME. [0108] 2. Method according to embodiment 1, wherein the fruit preparation is a puree. [0109] 3. Method according to embodiment 1 or 2, wherein the puree or the fruit used for the fruit preparation is subjected to heat treatment prior the enzymation step. [0110] 4. Method according to embodiment 3, wherein the heat treatment is performed at temperatures from 60 to 110° C., preferably from 75 to 95° C. [0111] 5. Method according to embodiment 3 or 4, wherein the heat treatment is performed for a duration of 30 seconds to 30 minutes, preferably for a duration of 5-10 minutes. [0112] 6. Method according to any one of embodiments 1 to 5, wherein a mechanical stress of 1 to 100 Pa, preferably of 3 to 20 Pa, is applied to the fruit preparation containing active PME, preferably by stirring, shaking, pumping or combinations thereof. [0113] 7. Method according to any one of embodiments 1 to 6, wherein the fruit preparation is a preparation selected from strawberry (Fragaria ananassa), peach (Prunus persica), apricot (Prunus armeniaca), fig (Ficus carica), pear (Pyrus), sour cherry (Prunus cerasus), cherry (Prunus avium), apple (Pyrus malus, Malus pumila), blueberry (Vaccinium cyanococcus), mango (Mangifera indica), banana (Musa acuminata); or mixtures thereof. [0114] 8. Method according to any one of embodiments 1 to 7, wherein the fruit preparation contains fruit pieces, or whole fruits. [0115] 9. Method according to any one of embodiments 1 to 8, wherein the fruit preparation contains further nutritional components, preferably cereals, seeds, nuts, or mixtures thereof. [0116] 10. Method according to any one of embodiments 1 to 8, wherein the stable fruit preparation consists of fruits in the form of fruit puree, fruit juice, fruit pieces, or mixtures thereof and inactivated PME. [0117] 11. Method according to any one of embodiments 1 to 10, wherein Ca.sup.2+ ions are present during production, especially wherein Ca.sup.2+ ions are present before inactivation of PME. [0118] 12. Method according to any one of embodiments 1 to 10, wherein no Ca.sup.2+ ions are added during production, especially wherein no Ca.sup.2+ ions are present before inactivation of PME. [0119] 13. Method according to any one of embodiments 1 to 12, wherein the preparation has a pH of 3.0 to 7.0, preferably of 3.2 to 5.5, especially of 3.5 to 4.2. [0120] 14. Method according to any one of embodiments 1 to 13, wherein the stable fruit preparation is packaged into a storage-stable form. [0121] 15. Method according to any one of embodiments 1 to 14, wherein the method further comprises a fruit heating step before addition of PME to the fruit preparation and a heating step after the enzymatic treatment with PME, especially a pasteurizing step, wherein preferably mechanical stress is also applied in the course of the heating step, especially at temperatures under 70° C. [0122] 16. Method according to any one of embodiments 1 to 15, wherein the enzymation step is performed for a duration of 1 to 120 min, preferably of 2 to 60 min, especially of 5 to 30 min. [0123] 17. Method according to any one of embodiments 1 to 16, wherein the enzymation step is performed at a temperature of 20 to 60° C., preferably of 30 to 50° C., especially of 35 to 40° C. [0124] 18. Method according to any one of embodiments 1 to 17, wherein the enzymation step is performed under stirring of 10 to 500 rpm, preferably of 20 to 100 rpm, especially of 30 to 50 rpm. [0125] 19. Method according to any one of embodiments 1 to 18, wherein the method further comprises a pasteurizing step with at least 60° C., preferably at least 70° C., especially at least 80° C. [0126] 20. Method according to any one of embodiments 1 to 19, wherein the method further comprises a pasteurizing step with a duration at least 1 min preferably at least 3 min, especially at least 5 min. [0127] 21. Method according to any one of embodiments 1 to 20, wherein the method further comprises a fruit heating step before addition of PME to the fruit preparation of at least 50° C., preferably at least 65° C., especially at least 75° C. [0128] 22. Method according to any one of embodiments 1 to 21, wherein the method further comprises a fruit heating step before addition of PME to the fruit preparation for a duration of 1 to 120 min, preferably of 2 to 60 min, especially of 5 to 30 min. [0129] 23. Method according to any one of embodiments 1 to 22, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 1, preferably at least 2, especially at least 3, Bostwick units in [cm/min]. [0130] 24. Method according to any one of embodiments 1 to 23, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 5, preferably at least 6, especially at least 7, Bostwick units in [cm/min]. [0131] 25. Method according to any one of embodiments 1 to 24, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 20%, preferably at least 25%, especially at least 30%. [0132] 26. Method according to any one of embodiments 1 to 25, wherein the method provides an improved consistency as determined by a reduction of Bostwick units of at least 40%, preferably 50%, especially at least 60%. [0133] 27. Method according to any one of embodiments 1 to 26, wherein the method excludes the addition of viscosity-lowering enzyme activity in the process. [0134] 28. Method according to any one of embodiments 1 to 27, wherein the method excludes the addition of polygalacturonase (PG) enzyme activity in the process. [0135] 29. Method according to any one of embodiments 1 to 28, wherein the fruit preparation is a preparation is not a Solanum fruit preparation, especially not a fruit preparation from potato, tomato or eggplant. [0136] 30. Method according to any one of embodiments 1 to 29, wherein the process, at least the enzymation step, is performed without applying high pressure of 300 MPa or more, preferably without applying a pressure of 180 MPa or more, especially wherein the enzymation step is performed at atmospheric pressure conditions.