Lactose-removing milk process for lactose-free milk production

Abstract

The present invention relates to dairy and milk treatment industries for obtaining lactose-free milk and assessment of byproduct in particular, particularly to milk treatment industry through different separation means such as micro and nanofiltration equipment. One of the purposes of this invention is to provide a delactosed or lactose-free milk with sensory profile equivalent to a normal pasteurized milk using essential separation steps to reduce product costs. Another purpose of this invention is to determine the effect of milk natural components concentration on organoleptic properties to achieve the first purpose of this invention. Another purpose is to determine percentage between retentate and permeate to get a sensory profile equivalent to a normal pasteurized milk.

Claims

1. A lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w, comprising standardizing semi-skim milk to 1.4 to 2.2% w/w of fat content; subjecting the semi-skim milk to an ultrafiltration UF step to produce an UF permeate and an UF retentate, subjecting the UF permeate to a diafilteration step and a nanofiltration NF step to produce a NF permeate diafiltered and a NF retentate diafiltered, which is maintained in a concentration of from 9 to 13 degrees Bx, while the diafilteration step is performed, until recovering the same volume of UF permeate; mixing the NF permeate diafiltered with the UF retentate to reconstitute the milk, achieving a desired lactose, lipid and protein content; subjecting the reconstituted milk to an UHT process; enzymatically hydrolyzing remaining lactose in the reconstituted milk from the UHT process, and packaging the reconstituted and enzymatically hydrolyzed milk; wherein the reconstituted milk having been subjected to the UHT process and to the enzymatically hydrolyzing has a lactose content between 2.7% and 3.5% w/w.

2. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the nanofiltration retentate maintains a retentate concentration 10 to 13 Bx while the diafiltration process is performed.

3. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the UF and NF steps remove from 35 to 40% by weight of lactose.

4. The lactose-removing milk process production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the proportions of the UF permeate and the UF retentate in the UF step are: from 55 to 63% by weight of UF retentate and from 37 to 45% by weight of UF permeate.

5. The lactose-removing milk process production of milk having a lactose content between 2.7% and 3.5% w/w production according to claim 1, wherein the proportions of the NF permeate and the NF retentate in the NF step are from 30 to 38% by weight of NF retentate and from 62 to 70% by weight of NF permeate.

6. The lactose-removing milk process production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the nanofiltration retentate diafiltered maintains a retentate concentration from 11 to 13 Bx while the diafiltration process is performed.

7. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the nanofiltration retentate diafiltered maintains a retentate concentration from 12 to 13 Bx while the diafiltration process is performed.

8. The lactose-removing milk process for production of milk having a lactose content between 2.8% and 3.4% w/w according to claim 1, wherein the reconstituted milk has a content from 2.8 to 3.4% w/w of lactose.

9. The lactose-removing milk process for production of milk having a lactose content between 2.9% and 3.3% w/w to claim 1, wherein the reconstituted milk has a content from 2.9 to 3.3% w/w of lactose.

10. The lactose-removing milk process for production of milk having a lactose content between 3.0% and 3.2% w/w to claim 1, wherein the reconstituted milk has a content from 3.0 to 3.2% w/w of lactose.

11. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w, according to claim 1, wherein the semi-skim milk is standardized to 1.4% by weight of fat content.

12. The lactose-removing milk process for lactose-free milk according to claim 1, wherein the proportions of the UF permeate and the UF retentate in the UF step are: from 56 to 62% by weight of UF retentate and from 38 to 44% by weight of UF permeate.

13. The lactose-removing milk process production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the proportions of the UF permeate and the UF retentate in the UF step are: from 57 to 61% by weight of UF retentate and from 39 to 43% by weight of UF permeate.

14. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the proportions of the UF permeate and the UF retentate in the UF step are: from 58 to 60% by weight of UF retentate and from 40 to 42% by weight of UF permeate.

15. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the proportions of the NF permeate and the NF retentate in the NF step are from 31 to 37% by weight of NF retentate and from 63 to 69% by weight of NF permeate.

16. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the proportions of the NF permeate and the NF retentate in the NF step are from 32 to 36% by weight of NF retentate and from 64 to 68% by weight of NF permeate.

17. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the proportions of the NF permeate and the NF retentate in the NF step are from 33 to 35% by weight of NF retentate and from 65 to 67% by weight of NF permeate.

18. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the UF and NF steps remove from 36 to 39% by weight of lactose.

19. The lactose-removing milk process for production of milk having a lactose content between 2.7% and 3.5% w/w according to claim 1, wherein the UF and NF steps remove from 37 to 38% by weight of lactose.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows process scheme of the present description, all the steps including.

(2) A detailed description of the invention is next, relying on examples for this purpose is carried out.

DETAILED DESCRIPTION OF THE INVENTION

(3) FIG. 1 shows a process scheme of the present invention, all the steps including. FIG. 1 shows standardized fat milk tank (1). Said milk is fed into ultrafiltration equipment (2), through broken line outlining the membrane. Line (2a) connecting retentate to tank (5). Line (2b) connects UF permeate to permeate tank (3).

(4) Line (3a) carries permeate of permeate tank to NF equipment (4). Line (3b) carries permeate with addition of water stored into retentate-diafiltration water mixture tank (7). Tank (9) contains water that is injected to NF retentate.

(5) A portion of the non-recirculated retentate is carried to the tank (8) wherein concentrated solution is concentrated.

(6) NF permeate is carried to mixing tank (5) wherein UF retentate is mixing with said NF permeate to get delactosed milk which is carried to tank (6), said delactosed milk receives enzymatic cleavage of lactose step.

(7) The first step in the process of this invention is to standardization of milk to be treated. Said standardization is accomplished with two milk components, fat concentration and protein concentration.

(8) Raw milk is standardized to required fat level, i.e., setting a value from 1.4 to 2.2%, preferably from 1.5 to 2.1, even more preferably from 1.6 to 2.0%, even more preferably from 1.7 to 1.9% of butterfat.

(9) Protein level after standardization is as follows: a value from 2.9 to 3.7%, preferably from 3.0 to 3.6, even more preferably from 3.1 to 3.5%, even more preferably from 3.2 to 3.4%.

(10) Next step is ultrafiltration to get a UF permeate and a UF retentate. Permeate is carried to nanofiltration (NF) step. UF retentate is mixing with NF permeate. UF permeate is subjected to NF process to get a retentate (water, lactose and minerals) and permeate (water and minerals).

EXAMPLES

Example I

(11) TABLE-US-00001 Test Date no. Activities Apr- P1 Methodology: 21th-14 Use of skim milk (2 g/L). Total solids concentration (SC) up to 12.8% (8.26% protein) using ultrafiltration process (UF). Reconstitution of milk using retentate and soft water to initial protein values of milk (3.1%), using only 2.12% of lactose. Heat treatment of milk-UHT Process- Enzymatic hydrolysis (using -galactosidase) of lactose remaining less than 1%. Results: Product obtained has a milky and sweet diluted profile Next steps: Raise the profile increasing fat level to 1.6%.

(12) In this example, skim milk has a butterfat content of 2 g/L. No nanofiltration has used and enzymatic hydrolysis of lactose remaining was less than 1%.

(13) The result was undesirable because the product was very sweet and diluted.

Example II

(14) TABLE-US-00002 May P2 Methodology: 9th-14 Use of skim milk (2 g/L). Concentration (SC) up to 12.98% (8.14% protein) using UF process. Reconstitution of milk using retentate and soft water to initial protein values of milk (3.1%), using only 2.2% of lactose. Standardization up to 1.6% of butterfat (BF) Heat treatment of milk-UHT Process- Enzymatic hydrolysis of lactose remaining less than 0.5%. Results: Product obtained has a dairy profile, more tan P1 but still less sweet diluted profile. Next steps: Explore the possibility of reducing the use of soft water and reinstate salts and possible flavor compounds that are lost in UF permeate through the inclusion of nanofiltration (NF) process.

(15) In this example, skim milk had the same butterfat content on treated milk of 2 g/L. concentration through UF has noticeably same concentrations of milk compounds.

(16) Product is less sweet than example 1, and has a dairy profile, however, has a thin consistency.

Example III

(17) TABLE-US-00003 May P3 Exploratory test process 21st-14 To evaluate the feasibility of processing UF permeate with NF process, in order to improve the dairy product profile retrieving salts and possible flavor compounds, thus decreasing the use of soft water. Methodology: Use of skim milk (2 g/L). Concentration (SC) up to 9.51% (4.2% protein) using UF process. Using UF permeate for processing by NF. Concentration of NF retentate up to 13.5 Bx max (the process stops at this point). Results: It is feasible to perform NF process using UF permeate and decreasing use of soft water for reconstitution of milk without adding lactose to reconstituted product. Next steps: To perform test using UF and NF processes.

(18) In this example, butterfat content on treated milk is the same, but concentration on final solids and protein is lower such that is less water with ultrafiltration step, because a nanofiltration step is applied to permeate.

(19) It is feasible performed NF process using UF permeate and using less soft water for reconstitution of milk.

Example IV

(20) TABLE-US-00004 May P4 Methodology: 28th-14 Use of skim milk (2 g/L). Concentration (SC) up to 14.32% (8.58% protein) using UF process. Using UF permeate for processing by NF. Concentration of NF retentate up to 12% of lactose. Reconstitution of milk using UF retentate, NF permeate and soft water to initial protein values of milk (3.2%), using only 1.7% of lactose. NO standardization is performed at a level of 1.6% of butterfat for the purpose of comparing the product obtained against only UF (P1). Heat treatment of milk-UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5%. Results: Product obtained improves dairy profile using these two processes versus P1, but still less sweet and diluted. Next steps: Establish minimum amount of remaining lactose in reconstituted milk having the same sweetness as initial milk. To identify the feasibility of using skim milk of 16 g/L. To determine whether additional homogenization and pasteurization processes retain more flavor compounds into fat globules.

(21) The result is still not acceptable, the product is diluted and sweetness is poor.

Example V

(22) TABLE-US-00005 Jun P5 Methodology: 18th-14 Use of skim milk (16 g/L). Pasteurization and homogenization of milk (72 C./16 s to 170 bar) Concentration up to 16.11% SC (8.7% protein) using UF process (see text in result section*). UF permeate processing through NF. NF retentate concentration up to 9.18% of lactose. Reconstitution of milk using UF retentate, NF permeate and soft water to initial protein values of milk (3.2%), with 2.525 of lactose (it had to standardize at this level of lactose*). PH adjustment using lactic acid, because acidity is lost during all filtration process. Heat treatment of milk-UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5%. Results: Product obtained has a better dairy profile, however sweetness is perceived slightly below to a pasteurized milk. Pasteurization and homogenization process does not contribute to the improvement of profile but also complicates operation and cost. There are major benefits using skim milk but: *Using skim milk, curve use on rapid methods equipment (Milkoscan) are not suitable due outliers observed during UF process monitoring, because of this, the product was more concentrated in UF step obtaining values above. Next steps: Develop a specific curve on Milkoscan to obtain reliable data during concentration process by opening with semi-skim milk. Explore the possibility of incorporating diafiltration process in NF step for improving mineral salts recovery and aromatic compounds, thereby eliminating the direct use of soft water.

Example VI

(23) TABLE-US-00006 Jun P6 Exploratoriy testing process 25th-14 Validate the curve drawn in Milkoscan equipment, monitoring data obtained with protein titration process. Explore diafiltration process during NF step to improve dairy profile of product and streamline the recovery of salts and possible aromatic compounds, thereby eliminate use of soft water directly in the reconstitution to get the same UF permeate volume. Methodology: Use of skim milk (2 g/L). Concentration up to 10.54% SC (4.69% protein) using UF process. Processing UF permeate through NF and diafiltration. Concentration of NF retentate using diafiltration process when indicates 12-13 Bx in retentate avoiding exceed these values until recovering the same volume of UF permeate. The final NF permeate concentration is up to 7.26% of lactose. Reconstitution of milk using UF retentate and NF permeate diafiltered to initial protein values of milk (3.07%), using only 3.26% of lactose. Standardization performed a level of 1.6% of butter- fat. Heat treatment of milk-UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5% Results: Product obtained has a better dairy profile with a noticeable decrease when diluted and sweetness is similar to a raw milk. Proper functioning of generated curve for this concentration process is shown. Feasible and beneficial the use of diafiltration process is shown. Next steps: To perform the process using semiskim milk. To use curve generated in Milkoscan for raw milk. To use diafiltration process in NF step.

(24) Product obtained has a better dairy profile, however, sweetness is lower than a pasteurized milk.

Example VII

(25) TABLE-US-00007 Jun P7 Methodology: 26th-14 Use of skim milk (16 g/L). Retentate concentration up to 14.96% SC (6.23% protein) using UF process and working pressure to 35 psi. UF permeate processing using NF and diafiltration. Final concentration of NF retentate using diafiltration to 9.32% of lactose (12.67% SC), up to 12 Bx during diafiltration ( Bx vary from 8 to 12). Working pressure on NF is up to 560 psi. Reconstitution of milk using UF retentate plus NF diafiltered permeate (soft water is removed) to initial protein values of milk (3.29%), remaining only 2.75% of lactose. Heat treatment of milk-UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5%. Results: Product obtained has better texture, dairy profile and same sweetness as pasteurized milk versus P6, but still has opportunity to optimize texture and sweetness. Next steps: To improve sweetness level through optimize lactose level from 3.1 +/ 1% in reconstituted milk. To achieve lower Bx width variation during diafiltration process keeping values in upper limit, that is, between 12 and 13 Bx.

(26) Following was obtained:

(27) Product obtained has better texture, dairy profile and same sweetness as pasteurized milk versus P6, but still has opportunity to optimize texture and sweetness.

Example VIII

(28) TABLE-US-00008 Jul 1st- P8 Methodology: 14 Use of semi skim milk (16 g/L). Retentate concentration up to 13.05% SC (5.02% protein) using UF process. UF permeate processing using NF and diafiltration. Final concentration of NF retentate using diafiltration to 7.66% of lactose (10.13% SC), up to 13 Bx during diafiltration ( Bx vary from 10 to 12.5). Reconstitution of milk using UF retentate plus NF diafiltered permeate to initial protein values of milk (3.26%), remaining only 3.27% of lactose. Heat treatment of milk-UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5 Results: Product obtained has better dairy profile and same sweetness as pasteurized milk, optimizing texture but still has opportunity to optimize versus pasteurized milk. To achieve lower Bx width variation and close variation. Next steps: To decrease Bx width variation during diafiltration process. Explore a reconstitution of milk to higher protein levels to optimize texture.

(29) Results obtained as follows:

(30) Product obtained has better dairy profile and same sweetness as pasteurized milk, optimizing texture but still has opportunity to optimize versus pasteurized milk.

(31) To decrease Bx width variation during diafiltration process but still close said variation.

Example IX

(32) TABLE-US-00009 Jul P9 Methodology: 16th-14 Use 1.4% of fat milk because fat is increased in reconstituted milk depending on the desired concentration level in UF retentate. Retentate concentration up to 14.14% SC (5.81% protein) using UF process. UF permeate processing using NF and diafiltration. Final concentration of NF retentate using diafiltration to 9.59% of lactose (12.94% SC), up to 13 Bx during diafiltration ( Bx vary from 10.5 to 12.5). Two reconstitutions of at different levels of protein (3.2 and 3.5%) using UF retentate plus NF diafiltered permeate are performed, remaining only 2.91% of lactose in 3.2% of protein and 3.03% of lactose in 3.5% of protein, both with 1.6% fat. Heat treatment of milk-UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5%. Results: Products obtained have better dairy profile, better than 3.5% of protein and slight lack of texture. It is a better control of Bx amplitude. Next steps: To perform reconstitutions of milk at different protein and fat levels (up to 1.8% keeping as low-fat milk)

(33) Products obtained have better dairy profile, better than 3.5% of protein and slight lack of texture.

Example X

(34) TABLE-US-00010 Jul P10 Methodology: 24th-14 Use 1.4% of fat milk. Retentate concentration up to 14.07% SC (5.63% protein). UF permeate processing using NF and diafiltration. Final concentration of NF retentate using diafiltration to 9.08% of lactose (12.29% SC), up to 13 Bx during diafiltration ( Bx vary from 10.5 to 12.5). Three reconstitutions of at different levels of protein (3.2 protein and 1.6% fat, 3.2% protein and 1.8% fat, 3.5% protein and 1.8 fat) are performed, remaining only 2.97%, 2.97% and 3.11% of lactose respectively using UF retentate plus NF diafiltered permeate. Heat treatment of milk-UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5%. Results: Product obtained has better dairy profile due to the difference in fat level. Difference in protein is low between 3.2 and 3.5% compared with fat from 1.6 to 1.8%. Best products are from 3.2 to 3.5% of protein with 1.8% fat. Profiles of these products are similar sweetness and texture to pasteurized milk, whiter presentation and non-overcooked. Next steps: To perform product with 3.3% of protein and 1.8% fat as final proposal.

(35) Protein difference is not as marked between 3.2 and 3.5% comparing fat between 1.6 and 1.8% found.

Example XI

(36) TABLE-US-00011 Aug P11 Methodology: 14th-14 Use 1.4% of fat. Retentate concentration up to 14.66% SC (5.7% protein). UF permeate processing using NF and diafiltration. Final concentration of NF retentate using diafiltration to 9.68% of lactose (13.24% SC), up to 13 Bx during diafiltration ( Bx vary from 11 to 12.5). Two reconstitutions of at different levels of protein (3.3 and 3.5% of protein) with 1.8% fat are performed, remaining only 3.13% and 3.14% % of lactose using UF retentate plus NF diafiltered permeate. Heat treatment of milk - UHT process- Enzymatic hydrolysis of lactose remaining less than 0.5%. Results: Both products are similar sensory to a pasteurized milk, whiter presentation and non-overcooked. It is recommended 3.3% protein and 1.8% fat.

(37) Best method known for applicant for carrying out the invention is that resulting from the present description.

(38) This invention has been sufficiently described so that a person with ordinary skills in present state of the art can reproduce and obtain results mentioned in said invention. If any person may be able to make modifications not described in said invention, said modifications in a lactose-removing milk process for lactose-free milk production and byproduct use, said modifications must be within scope of invention.