Method for making a dairy composition

Abstract

The invention relates to food products and to their methods of preparation. More particularly, the invention relates to cultured dairy products, especially cultured yogurt products and to their methods of preparation.

Claims

1. A method for making a dairy composition comprising the steps of: subjecting milk to an ultrafiltration step to produce an ultrafiltration permeate fraction and a ultrafiltration retentate fraction; subjecting the ultrafiltration permeate fraction to a nanofiltration step to produce a nanofiltration permeate fraction and a nanofiltration retentate fraction; subjecting the nanofiltration permeate to a reverse osmosis step to produce a reverse osmosis permeate fraction and a reverse osmosis retentate fraction; combining the ultrafiltration retentate fraction with water and the reverse osmosis permeate fraction to form a first mixture; subjecting the first mixture to a diafiltration step to produce a diafiltration permeate fraction and a diafiltration retentate fraction; mixing the nanofiltration retentate fraction with the diafiltration retentate fraction, cream and the reverse osmosis retentate fraction to form a second mixture; and incubating the second mixture with lactic-acid generating bacteria to convert lactose within the second mixture to lactic acid to form a sugar-free dairy composition.

2. The method of claim 1, wherein the second mixture has a pH of less than 5.0.

3. The method of claim 1, wherein the second mixture is incubated with the lactic-acid generating bacteria for 4-6 hours at 42° C.

4. The method of claim 1, wherein the sugar-free dairy composition is concentrated by reverse osmosis.

5. The method of claim 1, wherein the sugar-free dairy composition is concentrated by ultrafiltration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a first method of separating milk components.

(2) FIG. 2 illustrates a second method of separating milk components.

(3) FIG. 3 illustrates a third method of separating milk components.

SUMMARY OF THE INVENTION

(4) Embodiments of the invention provide dairy products and methods of preparing cultured dairy products such as stirred-style yogurt and set-style yogurt. Yogurt compositions of the invention are prepared by fermentation of a nanofiltration (NF) retenate fraction of milk, which is a lactose-rich fraction. The advantages of performing the fermentation process on the NF retentate fraction rather than whole milk including, the need of less culture and time required for the fermentation of NF retentate relative to whole milk, ability to separate fermentation bacteria more easily from the NF retentate fraction, and the ability to store the fermented retentate for future use as needed.

(5) If the cultures fail, only NF retentate (2% of the recipe) is required to be disposed, which is economical for the business and less harsh on environment. The acidified NF retentate is less viscous than acidified milk, therefore, need for pumps to handle viscous products would be reduced particularly for making stirred yoghurts.

(6) The invention finds particular suitability for use in connection with the provision of stirred style yogurts as well as set-style yogurts.

(7) Additionally, milk may be concentrated to a desired solid content of 16-24% by weight by a reverse osmosis process followed by culturing and fermentation.

(8) A further embodiment of the invention provides a method of adding a reverse osmosis concentrate of milk to a milk source in preparation for culturing.

(9) Another embodiment of the invention provides a method for concentrating a set yogurt made from cow's milk to a high solids yogurt by reverse osmosis concentration.

(10) In a further embodiment of the invention, the set yogurt may be subjected to an ultrafiltration process to increase the solids as required in certain types of yogurt such as Greek-style yogurt.

(11) Embodiments of the invention provide methods for preparing an improved cultured dairy product having decreased fermentation times.

DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

(12) The invention is directed to a process for preparing a yogurt composition having reduced production times, more specifically a yogurt having reduced fermentation times wherein the yogurt composition is prepared from a component of milk derived from a membrane fractionation process.

(13) An embodiment of the method of the invention provides for the use a membrane-fractionated component having a high concentration of lactose (9-20% by weight). For example, a raw material such as bovine milk is subjected to a membrane fractionation process as set forth in FIGS. 1-3. The fraction that represents the nanofiltration retenate (NF-R) component, which is a lactose-rich fraction, is collected. The NF-R fraction can be subjected to fermentation, and this fermented fraction can be used in the preparation of a dairy composition such as yogurt. Some of the advantages of performing the fermentation process on the NF retentate fraction rather than whole milk include, the need of less culture and time required for the fermentation of NF retentate relative to whole milk (as a result of the high lactose content), ability to separate fermentation bacteria more easily from the NF retentate fraction than from whole milk, and the ability to store the fermented retentate for future use (as a starter culture) as needed.

(14) In an embodiment of the invention, the NF-R fraction is subjected to fermentation using one or more strains of lactic-acid generating bacteria. The fermented NF-R fraction is combined with one or more additional components derived from the membrane fractionation process.

(15) An embodiment of the invention provides a method wherein the fermented NF-R fraction is mixed with a diafiltration retentate fraction, cream and a reverse osmosis retentate fraction. The mixture is maintained at a pH of less than 5.0. The mixture is placed in containers and incubated at 107.6° F. (42° C.) for 4-6 hours or 66-72° F. for 20-24 hours until a firm coagulum is formed. In this process sugar-free yogurt is obtained as the lactose in the yoghurts is converted to lactic acid by yogurt bacteria. In certain embodiments of the invention, the lactose in yogurt milk before fermentation is standardized to 1.5 to 2.0%. In this process the calorie value of yogurt is also reduced which is a benefit to those who watch their daily calorie consumption.

(16) An embodiment of the invention also provides a dairy product comprising 6% protein and 1.5 to 1.8% lactose wherein the lactose content is reduced by membrane filtration technology (FIGS. 1-3). The dairy product is inoculated with yogurt bacteria that convert any remaining lactose to lactic acid by bacterial fermentation thus resulting in a sugar-free yogurt.

(17) Processes according to the invention are also suitable for use in a wide variety of food products, such as other fermented milk products, fermented soy, rice and nut milk products, beverages and whipped toppings.

(18) Other milks can also be used in substitution for bovine milk whether in whole or in part, e.g., camel, goat, sheep, equine milk or mixtures thereof. The base mix can also comprise a vegetable milk such as soy milk.

(19) In certain embodiments of the invention, the bacteria from the fermented dairy base mix can be optionally removed by ultrafiltration or microfiltration for future use and the bacteria-free fermented dairy base is used for making yoghurt drinks.

(20) The dairy product can additionally include flavors. Illustrative flavors include vanilla, amaretto, cheesecake, white chocolate, Cafe Au Lait, caramel apple, banana cream, lemon, lime, various fruit and berry flavors, and mixtures thereof. Furthermore, these dairy products can contain flavors or fruits, can be frozen to provide a frozen composition or can be in the form of a drinkable fluid to provide a drinkable dairy composition.

(21) The dairy product can additionally include a conventional fruit sauce or puree. If present, the fruit constituent can comprise about 5% to about 15% of the cultured dairy base mix. The method can thus comprise the optional additional step of adding a fruit sauce or puree 40.

(22) In the manufacture of Swiss-style yogurt, a fruit sauce or puree is blended substantially uniformly throughout the cultured dairy base mix after fermentation is complete but prior to packaging.

(23) In the manufacture of “sundae” style yogurt, fruit sauce or puree is deposited at the bottom of the consumer container, and the container is then filled with the cultured dairy base mix. To prepare a sundae style yogurt product employing a stirred style yogurt, the cultured dairy base mix is prepared with added thickeners and/or stabilizer(s) to provide upon resting a yogurt texture that mimics a “set” style yogurt. In this variation, the fruit sauce or puree is added directly to the container, typically to the bottom, prior to filling with the cultured dairy base mix.

(24) The fruit sauce or puree used in the invention may be any of a variety of conventional fruit flavorings commonly used in yogurt products. Typical flavorings include cherry, kiwi, key lime, strawberry, raspberry, blueberry, strawberry-banana, boysenberry, cherry-vanilla, peach, pineapple, lemon, orange and apple. Generally, fruit flavorings include fruit preserves and fruit or fruit puree, with any of a combination of sweeteners, starch, stabilizer(s), natural and/or artificial flavors, colorings, water and citric acid or other suitable acid to control the pH.

(25) The products can additionally include a variety of other ingredients to increase their nutritional, organoleptic or other consumer appeal, e.g., fruit pieces, nuts, partially puffed cereals, etc.

(26) The invention will assist in establishing a centralized fermentation plant in multi-location factories, which will reduce the technical expertise requirement at all facilities for fermentation, culture propagation and storage of cultures.

(27) While the invention has been described in connection with what is presently considered to be the most practical and exemplary embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

(28) Throughout the specification and claims, percentages are by weight and temperatures in degrees Celsius unless otherwise indicated.