Use of Starch for Improving the Preparation of a Strained Fermented Dairy Product

Abstract

The present invention relates to a method for manufacturing a strained fermented dairy product comprising the following successive steps: (a) providing a dairy product containing starch, (b) fermenting the dairy product after adding lactic acid bacteria to obtain a fermented dairy product, and (c) separating a liquid whey from the fermented dairy product to obtain a strained fermented dairy product The present invention relates also to the use of starch for preventing the clogging of the separating device used in the preparation of a strained fermented dairy product.

Claims

1. A method for manufacturing a strained fermented dairy product comprising the following successive steps: (a) providing a dairy product containing starch, (b) fermenting the dairy product after adding lactic acid bacteria to obtain a fermented dairy product, and (c) separating a liquid whey from the fermented dairy product to obtain a strained fermented dairy product.

2. The method according to claim 1, wherein the dairy product provided in step (a) has a total protein content comprised between 2.8.

3. The method according to claims 1, wherein the strained fermented dairy product obtained has a total protein content comprised between 6 and 16%.

4. The method according to claims 1, wherein the starch is potato starch, tapioca starch, wheat starch, maize starch, rice starch, oat starch, barley starch, rye starch, cassava starch, sorghum starch or a mixture thereof.

5. The method according to claims 1, to wherein the starch is a granular or molecular starch.

6. The method according to claims 1, wherein the starch is in a native or modified form.

7. The method according to claims 1, wherein the starch is waxy maize starch or tapioca starch.

8. The method according to claims 1, wherein the dairy product contains 0.05 to 1.0 wt % of starch based on the total amount of the dairy product.

9. The method according to claims 1, wherein the fermentation step (b) is performed at a temperature kept between 25 C. and 44 C., for 3 to 25 hours.

10. The method according to claims 1, wherein the lactic acid bacteria used in step (c) are selected from Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus pentosus, Lactobacillus helveticus, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus bifidus, Lactococcus lactis, Bifidobacterium bifidum, Bifidobacterium infantis, Bifidobacterium animalis, Bifidobacterium breve, Bifidobacterium longum, Streptococcus thermophilus, Streptococcus lactis, Streptococcus raffinolactis, Streptococcus cremoris, and combinations thereof.

11. The method according to claim 10, wherein the lactic acid bacteria used in step (c) are selected from Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Lactococcus lactis, Bifidobacterium animalis subsp. lactis, and combinations thereof.

12. The method according to claims 1, wherein a lactase is added to the dairy product along with or before the lactic acid bacteria.

13. The method according to claims 1, wherein step (c) is performed by centrifugation.

14. The method according to claims 1, comprising, after step (c), an additional step (e) of cooling the strained fermented dairy product to a temperature of between 1 and 10 C.

15. (canceled)

16. The method according to claim 2, wherein the dairy product provided in step (a) has a total protein content comprised between 3.1 and 4.0%.

17. The method according to claim 3, wherein the strained fermented dairy product obtained has a total protein content comprised between 7 and 12%.

18. The method according to claim 7, wherein the starch is waxy maize starch or tapioca starch in a granular form.

19. The method according to claim 8, wherein the dairy product contains 0.1 to 0.5 wt % of starch based on the total amount of the dairy product.

20. A method for preventing the clogging of a separating device during the preparation of a strained fermented dairy product comprising the addition of starch during the preparation of said strained fermented dairy product.

Description

FIGURES

[0142] FIG. 1 presents photographs of disks clogging occurred in a method of manufacture of a strained fermented dairy product without starch.

[0143] FIG. 2 represents the graphs of total protein content in the obtained strained fermented dairy product (strained mass) and the separated whey in function of time, as well as the inlet flow in the separator device in function of time, during 6 hours and 30 minutes production with a centrifugal separator device at industrial scale.

[0144] FIG. 3 represents photographs of the two strained fermented dairy product, with or without starch, obtained in example 2.

[0145] FIG. 4 represents the evolution of the viscosity of the two strained fermented dairy product, with or without starch, obtained in example 2, during shelf life.

[0146] FIG. 5 represents the evolution of pH and Dornic acidity of the two strained fermented dairy product, with or without starch, obtained in example 2, during shelf life.

[0147] FIG. 6 represents the percent of whey release from the fermented dairy products of example 3 (with various texturizing agents) in comparison to the Reference product.

[0148] FIG. 7 represents the percent of whey release from the fermented dairy products of example 4 (with various starches) in comparison to the Reference product.

[0149] FIG. 8 represents the percent of whey release from the fermented dairy products of example 5 (with various starch dosages) in comparison to the Reference product.

[0150] FIG. 9 represents the total protein content in the strained fermented dairy products obtained in example 5 (with various starch dosages).

EXAMPLES

1. Evolution of Total Protein Content at the Outlet of the Separator Device During Separation Before and After Disk Clogging Appears

[0151] A strained fermented dairy product was prepared by fermenting a heat-treated skimmed dairy mix (prepared from skimmed milk and skimmed milk powder in proportions so as to obtain a total protein content of about 3.5%) with a culture of lactic acid bacteria consisting of a mix of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Lactococcus lactis subsp. lactis and Bifidobacterium animalis subsp. lactis.

[0152] The heat-treatment was performed according to the following steps: [0153] a first pre heat-treatment step to reach a temperature of about 65 C., followed by [0154] an homogenisation step at a pressure of about 50 bars (2 stages), followed by [0155] a second heat-treatment step at a temperature of about 92 C. for about 5 min.

[0156] The heat-treated dairy mix was fermented at 37 C. and went into lactic acidification until reaching a targeted pH of 4.60.

[0157] The fermented dairy product was then re-heated to an appropriate separation temperature, around 41 C., and then separated by a 12 nozzles centrifugal separation device to produce around of a strained fermented dairy product reaching a total protein content of about 10% and of whey.

[0158] After some hours of production, the total protein content in the strained fermented product at the outlet of the device suddenly decreases (below 9.3% total protein content) whereas the total protein content recovered in the whey increases the other way around (above 0.50%), without observing any fluctuation on the flows neither of the whey nor on the strained fermented mass outlet (see FIG. 2), due to a disk clogging of the centrifugal separation device (see FIG. 1).

[0159] When this effect appears, we observe a degradation of the main separation performance parameters: protein recovery rate decreases significantly (2% versus the starting phase of the production and getting worse when going ahead with the production) and the yield was increasing in the same way.

2. Impact of Starch Addition vs. the Reference

[0160] Two strained fermented dairy products were prepared as in example 1 using a 6 nozzles centrifugal separation device (KDB 16GEA Westfalia Nozzle separator). The first strained fermented dairy product corresponds to the one of example 1 before the clogging issue appears. The second fermented dairy product corresponds to the one of example 1, except that starch (Novation Endura 0100 from Ingredion at 0.5 wt % dosage) was added to the skimmed dairy mix before fermentation.

[0161] The analytical and process results observed for the two dairy products (with or without starch) after a separation step are reported in the table below:

TABLE-US-00003 Improvement Without With (with- Parameter Unit starch starch without) PRR (%) of protein 95.7 97 1.3 recovered in the final product Separator kg/h 3882 3690 192 feed flow Flow yield kg of dairy mix/kg 3.128 2.942 0.186 of final product Protein lost kg of proteins in 0.33 0.3 0.03 in whey the whey/kg of final product

[0162] The following responses during processing were thus observed: [0163] a) The total protein content measured in the whey from the fermented mix containing starch was lower than the one measured in the fermented mix without starch. It means that the losses of protein in the whey were lower. [0164] b) The inlet flow to feed the separator device was lower when separating the mix with starch than the feed flow needed with the mix without starch, for the same total protein targeted at the outlet of the centrifugal separator. [0165] c) The maximum proteins recovery rate (PRR) measured was higher in the fermented strained dairy product with starch. [0166] d) The milk consumption per kg of finished product was lower when separating the fermented dairy product with starch for the same total protein targeted at the outlet of the centrifugal separator.

[0167] The following sensory, physical and chemical analyses on the strained fermented dairy products were observed: [0168] a) No significant visual differences between the two products were observed (see FIG. 3). [0169] b) The viscosity of the two products has been measured with a Rheomat RM 200 at a shear rate of 64 s-1 and at 10 Cat 24 h after production (D+1) until D+50 (see FIG. 4). The product containing starch is significantly thicker than the product without starch; advantageously the texture of the product containing starch evolves much less than the the product without starch (product causing the clogging problem), making it more stable during shelf life. [0170] c) The pH of the two products has been measured at 10 C. with classical laboratory equipment and the Dornic acidity has been measured at 10 C. by addition of NaOH 0.1N until pH 8.35 (see FIG. 5). No significant impact of the addition of starch on pH or Dornic acidity was observed.

3. % of Whey Released By the Coagulum When Introducing Different Texturizing Agents in the Formula

[0171] Five different fermented dairy products were prepared as detailed in example 1 from the following dairy mixes: [0172] a) the skimmed dairy mix of example 1 (Reference product); [0173] b) the skimmed dairy mix of example 1 with an emulsifier (Grindsted Lactem PQ22 from Danisco) at a dosage of 0.68 wt %; [0174] c) the skimmed dairy mix of example 1 with a pectin (Grindsted Pectin SY640 from Danisco) at a dosage of 0.09 wt %; [0175] d) the skimmed dairy mix of example 1 with a starch (Novation Endura 0100 from Ingredion) at a dosage of 0.5 wt %; [0176] e) the skimmed dairy mix of example 1 with a gum (Fibergum B from CNI) at a dosage of 0.3 wt %.

[0177] The fermented dairy products were heated to the appropriate separation temperature, around 41 C., and then separated with a laboratory spin centrifuge: 4 samples of 40 g of each fermented dairy product, at 4000 rpm during 4 min. Then, the whey separated was weighted with a precision weighting device. The results obtained are presented on FIG. 6 as a percent of whey release in comparison to the Reference product.

[0178] Only the coagulum d) containing starch in the formula is able to release more whey than the reference meaning that the separation step is improved. No significant impact is observed for the use of gum, whereas the use of emulsifier or pectin has a negative impact on the capacity of releasing water from the coagulum.

4. % of Whey Released By the Coagulum When Introducing Different Types of Starches in the Formula

[0179] Five different fermented dairy products were prepared as detailed in example 1 from the following dairy mixes: [0180] a) the skimmed dairy mix of example 1 (Reference product); [0181] b) the skimmed dairy mix of example 1 with a modified tapioca starch (N-Dulge C1 from Ingredion) at a dosage of 0.8 wt %; [0182] c) the skimmed dairy with a modified waxy maize starch (N-Dulge C2 from Ingredion)at a dosage of 0.8 wt %; [0183] d) the skimmed dairy mix of example 1 with a dextrin from tapioca starch (Crystal TEX 626 from Ingredion) at a dosage of 1.25%; and [0184] e) the skimmed dairy mix of example 1 with a refined waxy maize starch (Endura 0100 from Ingredion) at a dosage of 0.5%.

[0185] The fermented dairy products were heated to the appropriate separation temperature, around 41 C., and then separated with a laboratory spin centrifuge: 4 samples of 40 g of each coagulum, at 4000 rpm during 4 min. Then, the whey separated was weighted with a precision weighting device. The results obtained are presented on FIG. 7 as a percent of whey release in comparison to the Reference product.

[0186] The addition of the various starches to the dairy product improved the quantity of whey released after the centrifugal separation, but it is not the case for the addition of the dextrin. Special increase of whey released was observed with the recipe e), using the non-modified waxy maize type starch.

5. % of Whey Released By the Coagulum When Introducing Different Doses of Starch in the Formula

[0187] Five different fermented dairy products were prepared as detailed in example 1 from five different dairy mixes containing 5 different dosages (0 wt %, 0.13 wt %, 0.25 wt %, 0.38 wt %, or 0.50 wt %) of refined waxy maize starch (Novation Endura 0100 from Ingredion).

[0188] The fermented dairy products were heated to the appropriate separation temperature, around 41 C., and then separated with a laboratory spin centrifuge: 4 samples of 40 g of each coagulum, at 4000 rpm during 4 min. Then, the whey separated was weighted with a precision weighting device. The results obtained are presented on FIG. 8 as a percent of whey release in comparison to the Reference product (comprising 0 wt % starch). The total protein content of the strained fermented dairy product obtained is also presented on FIG. 9.

[0189] These results show that the separation step is improved in the presence of starch, whatever the starch dosage used. However the impact of starch dosage on the whey release capacity is not linear; to reach a maximum amount of water releasing capacity, there is an optimum dosage of starch. Below or above this dosage, the amount of released whey is lower. In the same way, the total protein content reached in the separated mass increased up to this optimum starch dosage; above it, the total protein concentration decreases.

[0190] Without wishing to be bound by any theory, the inventors are of the opinion that when adding too high amount of starch, the coagulum viscosity increases, making the whey separation by centrifugal force more difficult than with an optimised dosage. Advantageously, an optimised starch dose will produce an improvement of the separation capacity of the dairy fermented curd, without impacting too much the viscosity and the corresponding sensory profile, thus, getting closer to the reference (without any starch).