LIQUID COMPOSITION COMPRISED OF A MICELLAR CASEIN CONCENTRATE

Abstract

A liquid composition comprised of a micellar casein concentrate (MCC), more specifically a MCC that is of non-bovine origin. Food products comprised of the liquid composition and methods for the production of the liquid composition of present invention.

Claims

1. A=liquid composition comprising: a micellar casein concentrate (MCC) of goat origin, wherein the MCC comprises between 60 to 90 wt % protein, based on total dry weight of the composition, wherein the composition has a dynamic viscosity of at most 100 mPa.Math.s, wherein the MCC comprises a casein to whey ratio of at least 85:15, and wherein the composition has a pH of between 6.5 to 7.2.

2. The liquid composition according to claim 1, wherein the MCC further comprises less than 50 wt %, of lactose based on total dry weight of the composition.

3. The liquid composition according to claim 1, wherein the MCC further comprises a surfactant and/or emulsifying agent.

4. A flood product, wherein said food product is a powder comprised of a micellar casein concentrate (MCC) of goat origin, wherein the MCC comprises between 30 to 90 wt % protein, based on total dry weight of the MCC, wherein the MCC comprises a casein to whey ratio of at least 85:15 and has a pH of between 6.5 to 7.2, and wherein the food product comprises at least 8 wt % protein based on total dry weight of the food product.

5. The flood product according to claim 4, wherein the MCC comprises less than 1 wt % of lactose based on total dry weight of the MCC.

6. The flood product according to claim 4, wherein the food product is one or more selected from the group consisting of instant powder formulations, infant formula, sport drinks, medical nutrition, elderly nutrition, and tube feeding.

7. A method for production of the liquid composition according to claim 1, wherein the method comprises the steps of, a) heat treating goat milk, wherein the goat milk has a fat content of at most 0.1 wt %, and wherein by heat treating a soluble casein fraction of the goat milk is reduced to a concentration of between 1 to 6%, based on the total casein content in the milk. b) microfiltrating the heat treated goat milk providing a permeate and a retentate, wherein the retentate comprises a micellar casein concentrate, and c) collecting the retentate comprised of the micellar casein concentrate.

8. The method according to claim 7, wherein the method further comprises at least one additional step d) of concentrating the retentate of step b) to obtain a micellar casein concentrate comprised of at least 75 wt % protein, based on total dry weight of the composition.

9. The method according to claim 7, wherein the method further comprises the step e) of reducing the lactose content of the micellar casein concentrate to at most 5 wt %, preferably at most 1 wt %, more preferably at most 0.1 wt % based on total dry weight of the composition.

10. The method according to claim 9, wherein the step e) is performed by membrane filtration, enzymatic treatment or liquid chromatography, or a combination thereof.

11. The method according to claim 7, wherein the method further comprises a step f) drying of the micellar casein concentrate to obtain goat MCC powder.

12. The method according to claim 7, wherein heating in step a) is comprised of pasteurization at a temperature of between 68 to 90° C., preferably 70 to 82° C., more preferably between 72 to 76° C.

13. The liquid composition according to claim 2, wherein the MCC further comprises a surfactant and/or emulsifying agent.

14. The food product according to claim 5, wherein the food product is one or more selected from the group consisting of instant powder formulations, infant formula, sport drinks, medical nutrition, elderly nutrition, and tube feeding.

15. The method according to claim 8, wherein the method further comprises the step e) of reducing the lactose content of the micellar casein concentrate to at most 5 wt % based on total dry weight of the composition.

16. The method according to claim 15, wherein the step e) is performed by membrane filtration, enzymatic treatment or liquid chromatography, or a combination thereof.

17. The method according to claim 15, wherein the method further comprises a step f) drying of the micellar casein concentrate to obtain goat MCC powder.

18. The method according to claim 16, wherein the method further comprises a step f) drying of the micellar casein concentrate to obtain goat MCC powder.

19. The method according to claim 8, wherein the heating in step a) is comprised of pasteurization at a temperature of between 68 to 90° C.

20. The method according to claim 18, wherein heating in step a) is comprised of pasteurization at a temperature of between 68 to 90° C.

Description

[0030] Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings and examples, in which:

[0031] FIG. 1: shows the dynamic viscosities of the cow MCC and goat MCC solutions as a function of shear rate, protein content (3.5, 8 and 12 wt %) and pH. The viscosities were found to increase with protein concentration, as well as with increasing pH, as expected. The viscosities of the bovine and caprine samples were similar at 3.5% (m/m) protein content. The differences in viscosity became larger at higher concentrations, where the goat MCC solutions showed considerably lower viscosity than the corresponding cow MCC references.

[0032] FIG. 2: shows the protein voluminosity of the cow MCC and goat MCC solutions at various pH and protein content, as determined with the Krieger-Dougherty formula based on the dynamic viscosities. The voluminosity of the goat MCC proteins were found to be lower than that of the cow MCC proteins, indicating a lower water-holding capacity of the goat milk proteins, particularly of the goat casein.

[0033] FIG. 3: shows the reducing SDS-PAGE gels obtained from skimmed goat milk treated at different temperatures. M: total sample, A: acid supernatant, R: rennet supernatant. C: fresh skimmed milk, 4: skimmed milk at 4° C., 70: skimmed milk treated at 70° C., 80: skimmed milk treated at 80° C., 90: skimmed milk treated at 90° C., P: pasteurized skimmed milk (80° C./15 s).

[0034] FIG. 4: shows the amount of soluble casein protein quantified in the different samples using ImageJ. Milk: fresh skimmed goat milk, Milk 70: skimmed goat milk treated at 70° C. for 10 minutes, Milk 80: skimmed goat milk treated at 80° C. for 10 minutes, Milk 90: skimmed goat milk treated at 90° C. for 10 minutes, Pasteurized goat Milk: skimmed milk treated at 80° C. for 15.

EXAMPLES

[0035] Determination of viscosity and voluminosity of cow and goat micellar casein concentrate (MCC) Viscosity

[0036] To determine the viscosity and to calculate the voluminosity of goat and cow MCC solutions, goat MCC and cow MCC powders were reconstituted. In Tables 1, the amounts of ingredients necessary for preparing 100 g of goat MCC solution and of cow MCC solution, respectively, at 3.5, 8.0 and 12.0 (wt %) protein content and equivalent dry matter content are shown. The composition of the cow MCC was standardized using bovine ultrafiltration (UF) milk permeate to match both the protein and dry matter contents of the corresponding goat MCC solutions.

TABLE-US-00001 TABLE 1 Milk cow MCC Permeate 10% NaN.sub.3 H.sub.2O Total 100 g cow MCC solution at 3.5 wt % protein Amount (g) 4.4 21.9 0.2 73.5 100 Dry matter (%) 4.3 1.2 0 0 5.5 Protein (%) 3.5 0 0 0 3.5 100 g cow MCC solution at 8 wt % protein Amount (g) 10.1 75.1 0 9.7 100 Dry matter (%) 9.8 2.7 0 0 12.5 Protein (%) 8.0 0 0 0 8.0 100 g cow MCC solution at 12 wt % protein Amount (g) 15.2 75.1 0 9.7 100 Dry matter (%) 14.7 4.0 0 0 18.7 Protein (%) 12.0 0 0 0 12.0 goat MCC 10% NaN.sub.3 H.sub.2O Total 100 g goat MCC solution at 3.5 wt % protein Amount (g) 5.7 0.2 94.1 100 Dry matter (%) 5.5 0 0 5.5 Protein (%) 5.3 0 0 5.3 100 g goat MCC solution at 8 wt % protein Amount (g) 13.0 0.2 86.8 100 Dry matter (%) 12.5 0 0 12.5 Protein (%) 8.0 0 0 8.0 100 g goat MCC solution at 12 wt % protein Amount (g) 19.5 0.2 80.3 100 Dry matter (%) 18.7 0 0 18.7 Protein (%) 12.0 0 0 12.0

[0037] The powders were reconstituted overnight at approximately 5° C. to ensure proper rehydration. The natural pH value of the standardized cow MCC and goat MCC solutions reconstituted at 3.5 wt % protein content was about 6.9. Therefore the pH values of 6.6 (0.3 units below natural), 6.9 (natural) and 7.2 (0.3 units above natural) were selected for further experiments. For consistency of the results, the concentrated solutions at 8.0 and 12.0 wt % protein were also adjusted to the indicated pH values. The pH adjustment was performed using 1 M HCl or 1 M NaOH.

[0038] Viscosity of the various MCC solutions was measured at 20° C. as a function of shear rate on the upward curve from 1 to 200 s.sup.−1, and again on the downward curve from 200 to 1 s.sup.−1 with a rheometer using a cup-and-bob geometry. Mixtures of reverse osmosis (RO) and ultra filtration (UF) milk permeate were used to prepare solutions corresponding to the serum phase of each sample; the viscosity of these solutions was measured (η.sub.s) and introduced into the Krieger-Dougherty formula to calculate protein voluminosity:

[00001]$\eta ={\eta }_s.Math.{\left(1-\frac{\phi }{{\phi }_{\max }}\right)}^{-2.3.Math.{\phi }_{\max }}$$\mathrm{And}$$\phi =v_s.Math.c$

[0039] Where [0040] η=dynamic viscosity of the solution (Pa.Math.s); [0041] ϕ=volume fraction of particles at measurement concentration; [0042] ϕ.sub.max=maximum volume fraction of particles; [0043] η.sub.s=dynamic viscosity of the serum phase (Pa.Math.s); [0044] 2.5=shape factor for spherical particle; [0045] v.sub.s=voluminosity (mL/g); [0046] c=concentration (g/mL).

[0047] The viscosities of the cow MCC and goat MCC solutions were found to increase with protein concentration, as well as with increasing pH, as expected, see FIG. 1. The viscosities of the bovine and caprine samples were similar at 3.5 wt % protein content. The differences in viscosity became larger at higher concentrations, where the goat MCC solutions showed considerably lower viscosity than the corresponding cow MCC references. Results indicate that the goat MCC proteins have a lower viscosity contribution than their cow MCC counterparts at the same concentration and under the same experimental conditions. The viscosity of goat MCC was found to increase less than that of the bovine proteins with increasing pH, particularly at 8.0 and 12.0 wt % protein content.

[0048] Voluminosity

[0049] The voluminosity of the proteins was determined with the Krieger-Dougherty formula based on the dynamic viscosities of the whole solutions and the continuous phases (FIG. 2). Following a similar trend as observed for viscosity, the voluminosity of the goat MCC proteins were found to be lower than that of the cow MCC proteins.

[0050] Summarizing the above, these results indicate that goat MCC is a suitable ingredient for applications in high-protein products where a high viscosity is not desirable, e.g., medical and clinical beverages, sports and nutritional beverages, meal-replacement beverages, weight management beverages, smoothies, fat-reduced products by increasing protein. The voluminosity of the proteins from goat MCC is lower than that of the proteins from the cow MCC, indicating a lower water-holding capacity of the goat milk proteins, particularly of the goat casein.

[0051] Pasteurization Heat Treatment of Goat Milk and Determination of Protein Interaction

[0052] The influence on goat milk protein interaction from pasteurization heat treatment was examined with fresh skimmed goat milk and pasteurized skimmed goat milk obtained from Ausnutria (Ausnutria Ommen, The Netherlands). The samples were stored at 4° C. overnight. Three aliquots of fresh skimmed goat milk (10 mL) were transferred to individual plastic tubes and closed with a screw cap. The samples were heated at 70, 80 or 90° C. for 10 minutes using a water bath, after equilibrating the sample at the corresponding temperature for 3 minutes Immediately after heat treatment, the samples were cooled to room temperature using cold tap water. Pasteurized skimmed goat milk was obtained from the pasteurization process at 80° C. with a holding time of 15 seconds.

[0053] Protein separation was performed by fractionation of on six different milk samples: Fresh skimmed milk (C), fresh skim milk equilibrated at 4° C. (4), fresh skimmed milk heated at 70, 80 and 90° C. (70, 80 and 90 respectively), pasteurized skimmed milk (P). To determine the soluble casein fraction in the milk samples, the samples were treated according to the method described by Pesic et al. (2012), “Heat induced caseing whey protein interactions at natural pH of milk: A comparison between caprine and bovine milk”, Small Ruminant Research, 108(1), 77-86. In summary, the soluble casein fraction was separated from the micellar fraction (=insoluble fraction) using either acid precipitation (A) or rennet coagulation (R).

[0054] Acid Precipitation (A):

[0055] Dilute the samples (0.3 mL) by adding 0.6 mL of distilled water, and 30 μL of 10% (w/w) acetic acid. Mix for 10 minutes, then dilute by addition of 30 μL 1M sodium acetate, and 540 μL of distilled water. Mix for 10 minutes and centrifuge sample at 3000×g for 5 minutes to obtain the supernatant.

[0056] Rennet Coagulation (R):

[0057] Add 20 μL of rennet solution (4.4 IMCU) to 1000 μL of milk sample and incubate at 35° C. for 1 hour. Centrifuge sample at 3000×g for 10 minutes to obtain supernatant.

[0058] SDS Electrophoresis

[0059] The protein profile of each milk sample was assessed using reducing SDS-PAGE. Total milk samples were diluted to a final protein concentration of 4 μg/μL. To compare the supernatant samples with the milk samples on an equal basis, rennet supernatant was diluted with a final dilution factor of 7.5 (same as the milk samples), while the acid supernatant was diluted 1.65 times to obtain a final dilution factor of 7.5 using distilled water. Diluted samples were then diluted 4 times with NuPAGE SDS-reducing buffer (1 μg of protein/4, in the milk samples). Samples were loaded (10 μL) on to precast gels 12% Bis-TRIS (1.0 mm×15 well; Novex, Life Technologies, Carlsbad, Calif.) and run for 50 min at 200 V. The gels were then stained with 0.25% (wt/vol) SimplyBlue™ SafeStain and destained using distilled water.

[0060] Gel Quantification

[0061] Quantification of individual protein bands is obtained using the open source software ImageJ. The software used the colour intensity of the band to quantify the protein concentration. The soluble casein present in the rennet supernatant was quantified as percentage of the total casein content in the total fresh skimmed milk sample.

[0062] FIG. 3 shows the reducing SDS-PAGE gels and highlights the influence of heat treatment on the stability of whey proteins and soluble caseins in the serum phase of goat milk. The higher the temperature used in the heat treatment applied to the goat milk, the more aggregation within the micellar casein of the whey proteins are observed, resulting in a decrease of the corresponding band intensity in the rennet and acid supernatant samples. This decrease of intensity is most obvious in the rennet supernatant of the milk treated at 90° C. (R90), where only a faint band is visible for α-lactalbumin and β-lactoglobulin. It can also be observed that, similar to the whey proteins, the bands that correspond to the soluble caseins show a decrease in intensity with increasing severity of the heat treatment. Our hypothesis is that similar to the whey proteins, the soluble caseins are irreversibly bound to micellar casein due to the heat treatment.

[0063] Quantification of the intensity of the casein bands was performed in the rennet supernatant samples (R70, R80, R90 and Rp), and expressed as relative value to the total casein content determined in fresh skimmed milk. In FIG. 4, it can be observed that for fresh skimmed goat milk approximately 7.5% of the caseins are present in the soluble fraction. After heat treatment of goat milk, the soluble casein fraction was reduced to a minimum of 1.3% at 90° C./10 minutes. These results show that by adjusting the heat treatment, the fraction of soluble caseins can be modified accordingly. This effect is beneficial because the low soluble casein fraction obtained after the heat treatment will increase the efficiency of the filtration process by reducing the permeation of soluble casein. Therefore, decreasing of soluble casein fraction in (skimmed) goat milk by heat treatment (e.g. pasteurization) will increase the yield of casein retention during the microfiltration process.

[0064] The present invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following clauses within the scope of which many modifications can be envisaged.