Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
  • A23C9/00—Milk preparations; Milk powder or milk powder preparations
  • A23C9/15—Reconstituted or recombined milk products containing neither non-milk fat nor non-milk proteins
  • A23C9/1512—Reconstituted or recombined milk products containing neither non-milk fat nor non-milk proteins containing isolated milk or whey proteins, caseinates or cheese; Enrichment of milk products with milk proteins in isolated or concentrated form, e.g. ultrafiltration retentate
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
  • A23C9/00—Milk preparations; Milk powder or milk powder preparations
  • A23C9/12—Fermented milk preparations; Treatment using microorganisms or enzymes
  • A23C9/1203—Addition of, or treatment with, enzymes or microorganisms other than lactobacteriaceae
  • A23C9/1206—Lactose hydrolysing enzymes, e.g. lactase, beta-galactosidase
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
  • A23C9/00—Milk preparations; Milk powder or milk powder preparations
  • A23C9/14—Milk preparations; Milk powder or milk powder preparations in which the chemical composition of the milk is modified by non-chemical treatment
  • A23C9/142—Milk preparations; Milk powder or milk powder preparations in which the chemical composition of the milk is modified by non-chemical treatment by dialysis, reverse osmosis or ultrafiltration
  • A23C9/1422—Milk preparations; Milk powder or milk powder preparations in which the chemical composition of the milk is modified by non-chemical treatment by dialysis, reverse osmosis or ultrafiltration by ultrafiltration, microfiltration or diafiltration of milk, e.g. for separating protein and lactose; Treatment of the UF permeate

Definitions

• This invention relates to a process for reducing or substantially eliminating lactose from milk.
• This invention further relates to a lactose- free milk which has preserved organoleptic properties.
• This invention also relates to a partially or totally defatted and lactose-free milk which has preserved organoleptic properties.
• a soy based milk which does not naturally comprise lactose, is an acceptable alternative under circumstances where lactose intolerance occurs or where lactose is to be avoided for a given period of time.
• lactose intolerance occurs or where lactose is to be avoided for a given period of time.
• many individuals reduce or eliminate milk consumption because they dislike the taste of soy-based milk.
• Enzymatic processes used to eliminate lactose from milk are well known in the art. They usually comprise the step of adding lactase to milk for a time sufficient to convert lactose into monosaccharides. The major problem occurring with this type of process is that the production of monosaccharides increases the taste of the milk to an unacceptably sweet level.
• US Patent No. 4,957,752 describes a process for making an ultrafiltrated milk which is used in the production of kefir. A partial delactosylation is achieved which reduces the ratio of lactose to protein from about 1.5:1 to about 1:1 (measured as percentages on a dry weight basis).
• This reference does not identify any undesirable modifications of the organoleptic properties of milk so delactosylated and further treated with a lactase, and consequently does not provide solutions for solving the problem arising from the action of lactase.
• US Patent publication No. 4,956,186 describes a process for making yogurt. This process also comprises the steps of ultrafiltering milk and hydrolysing lactose with a lactase. Apparently the sweet taste of the resulting milk was not a concern in this reference, because a sugar substitute was added to the yogurt.
• the present invention provides a solution to the drawbacks or inconveniences of existing processes and milk products.
• the milk having a residual lactose content has about 3% lactose on a dry weight basis, and is obtained by membrane technology. Specifically, ultrafiltration and diafiltration were used.
• the milk is standardized to achieve a fatty matter content of about 0 to about 3.25% on a dry weight basis.
• the fatty matter content is standardized to about 3.25%.
• the fatty matter content is standardized to about 0%.
• the above process leads to a fat-free and lactose-free product.
• the organoleptic properties of the skimmed milk so treated are improved by increasing the milk protein over the natural protein content of milk, preferably up to about 3.8-4.0% or greater on a dry weight basis.
• the milk protein content may be increased by concentrating the original milk or by adding proteins to said original milk or to the milk having residual lactose content, or else to the milk treated with lactase.
• the added proteins may be milk proteins or proteins from any exogenous source.
• Figure 1 outlines the steps of a process according to the present invention.
• the process begins with a cow milk, the lactose content of which is to be reduced from an original average value of 4.6 - 4.9% to a value below the detection level thereof, as verified by enzymatic assays (i.e., below about 0.2%). This is considered to be a substantially complete removal of lactose.
• the protein content (N x 6.38) and the total fat matter content were determined in duplicate using the standard method of Kjeldahl and Mojonnier, respectively.
• the lactose content was measured by a technique well known in the art, such as Boehringer & Mannheim Enzymatic Method.
• Non-processed milk usually has the following average composition:
• the first step is a partial or total removal of fatty matter, or standardization, of the milk contents. Levels of fatty matter usually vary from 0 to 3.25% on a dry weight basis.
• the second step of the present process is usually a thermal treatment. The goal of this step is two-fold: (1) to destroy pathogenic agents in the milk; and (2) to increase the permeation speed during the following ultrafiltration step, thereby reducing the clogging rate of the filtering walls.
• Thermal treatment is not essential to the present invention if one or both of the above goals are not sought.
• standardized milk having 3.25% fatty matter was heated at 72.8 °C for a period of 16 seconds.
• the pressure used for the heat treatment may vary upon the nature of the equipment and the method itself.
• the equipment used was a Tetra PakTM system and the parameters for heat treatment were chosen in accordance with the manufacturer's recommendations.
• the heat-treated milk was allowed to cool down to the temperature used during the ultrafiltration step.
• Many other temperature and time schedules may be used in replacement of the one mentioned above, as may be appreciated by a person skilled in the art.
• the third step is an ultrafiltration/diafiltration step.
• the filtration temperature is stabilized.
• the filtration temperature affects the permeation speed.
• An increase of 1 °C has the effect of increasing the permeation speed by about 2.5%.
• the filtration temperature should never exceed the maximum temperature suggested by the manufacturers of filtration membranes.
• the filtration system used was Tetra PakTM with RomiconTM PM50 filtration membranes and the filtration parameters were the following: Temperature ⁇ 50°C
• the retentate is submitted to diafiltration by addition of water so as to decrease the lactose content from about 4.6 - 4.9% to about 3%.
• the content ratio of lactose to protein is about 1 :1.
• the reduction of the lactose content or ratio is a key feature of the present invention.
• the lactose content is reduced to about 3% and the protein content is of about the same percentage value (on average, about 3.1 - 3.3%), and further, when the fatty matter content is of about 3.25%, the conversion of the residual lactose into monosaccharides will result in the production of a milk with an unnoticeable change in sweetness.
• the order of the subsequent fourth and fifth steps comprising thermal treatment and enzymatic hydrolysis may be interchanged.
• the objective of the thermal treatment is to destroy pathogens and is based upon the intensity and the time selected for the heat treatment.
• the heat intensity influences the organoleptic and nutritional properties of the finished product and its conservation time. For example, a low temperature/long time process
• LTLT consists of heating at 65.6°C for 30 minutes.
• HTST high temperature/short time
• the ultrahigh temperature process (UHT) consists of heating at 120°C for only a few seconds.
• the heat treatment UHT was selected to ensure sterility for commercial purposes (see above parameters). It is worthwhile noting that
• LTLT and UHT have a more pronounced denaturing effect on proteins than the HTST heat process.
• the HTST heat treatment was combined with known methods of multicentrifugation and microfiltration in order to avoid denaturing the milk without compromising on acceptable microbial quantities. A sterile, agreeable milk product having a long shelf life was obtained.
• the advantage is that it takes a longer time for the heat exchanger to become clogged.
• the heat treatment may follow enzymatic hydrolysis.
• the enzymatic hydrolysis step itself has as an object the conversion of the residual lactose (about 3%) of the diafiltered milk into glucose and galactose.
• the enzyme should be added after the heat treatment, it should be in a sterile form if the finished product is to have a lengthy conservation time. If heat treatment follows enzymatic hydrolysis, the enzyme ⁇ - galactosidase (or lactase) will be denatured and will lose its activity, and the sterility of the final product will be ensured.
• Lactose hydrolysis was performed with ⁇ -galactosidase in accordance with the manufacturer's directives.
• Many commercial enzymes are available, such as those sold under the following trade names: LactaidTM, LacteezeTM, DairyaidTM and PMS-prolactaseTM.
• the incubation temperature is decreased when the product is non-sterile after heat treatment because of the introduction of the enzyme.
• the last step of the above process is a usual conditioning step which is performed in accordance with available equipment.
• the EQ5 process was used.
• the diameter of fat vesicles resulting from homogenization should be less than about 1 micron in order to avoid separating the lipidic and aqueous phases.
• the final product may be aromatized by adding any flavor, or further processed.
• Example 1 The steps of Example 1 were reproduced starting with an original milk having a fatty matter standardized to about 0%.
• the watery and sweet taste of the skimmed milk so-treated may be greatly improved by increasing the concentration of protein from about 3% (i.e., 3.1 to 3.3%) to about 3.8-4.0% or greater. This increase was achieved during the ultrafiltration/diafiltration step performed on the original milk (i.e., by concentrating milk proteins).
• proteins may be added at any step, such as after diafiltration or after complete hydrolysis of lactose. This simple increase in proteins rendered the fat-free and lactose-free milk significantly more acceptable to consumers involved in taste trials.
• a plurality of dairy products may be derived from the milk produced in accordance with the present invention. "Derived” should be construed as "obtained by milk transformation or as a milk-comprising food product”.
• Any such dairy product (cream, ice cream, yogurt, butter, cheese, beverage etc.) is contemplated as being under the scope of the invention.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Food Science & Technology (AREA)
• Polymers & Plastics (AREA)
• Microbiology (AREA)
• Water Supply & Treatment (AREA)
• Dairy Products (AREA)

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Cited By (18)

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Citations (3)

• 1999
  • 1999-02-04 CA CA002260673A patent/CA2260673A1/en not_active Withdrawn
• 2000
  • 2000-02-04 WO PCT/CA2000/000110 patent/WO2000045643A1/en active Application Filing
  • 2000-02-04 AU AU25283/00A patent/AU2528300A/en not_active Abandoned
• 2002
  • 2002-04-15 US US10/121,581 patent/US6881428B2/en not_active Expired - Lifetime

Patent Citations (3)

Non-Patent Citations (2)

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