GB2190273A - Food dressing for cottage cheese production - Google Patents

Abstract

The dressing for use in the production of cottage cheese is made by mixing together cheese whey and dairy cream to produce a first mixture containing from 4% to 16% w/w of fat, and adding to this mixture a whey protein in an amount to provide from 1 to 10%, preferably 2% to 5% w/w of whey protein in the final mixture, homogenising the final mixture, subjecting the homogenized mixture to pasteurisation at elevated temperature and cooling the pasteurised mixture to below ambient temperature. <IMAGE>

Description

SPECIFICATION Food dressing for cottage cheese production The present invention relates to stabilized food dressings and more particularly, to stabilized food dressings which do not contain synthetic stabilisers.

One of the best known types of soft cheese currently on sale is generally known as cottage cheese, and often described as a low fat soft cheese or a skimmed milk soft cheese. Cottage cheese may be produced by blending curd grains derived from skimmed milk, with a cream based dressing.

The methods used for making the cottage cheese curd from the skimmed milk are broadly similar throughout the industry. In one method milk is pasteurised, cooled to a temperature around 31 Centigrade and then innoculated with a starter culture of bacteria and calf rennet.

The starter culture is homofermentative and produces acid, but not gas. It is the acid that causes the coagulation of the skimmed milk to give the cottage cheese curd. The rennet is added to give the product curd extra firmness when cut. The pH of the clotting milk falls due to the acid production, from an initial level of about pH 6.6 to 7 to a final pH 4.65 to 4.75, which is the cutting pH.

The clotted milk is then cut (e.g. with wire knives) into even cubes of curd. The pH at which cutting is carried out depends inter alia on the type of curd being produced, the object being that the final curd will have a pH of about 4.6 at the end of the subsequent cooking or scalding process. The biochemical basis for selection of the cutting pH, is that the isoelectric point of casein occurs at this pH and therefore at a pH of 4.6 casein is in a state of minimum solubility.

The selection of the cutting pH is important since it affects the texture of the curd and because the curd is mostly casein and water, the resulting cheese. If the curd is cut at too high a pH, it can be too firm and rubbery, while if it is cut at too low a pH, the curd tends to be very soft, difficult to drain, and may break up later in the process. After being cut, the curds are left for 10 to 15 minutes to heal, during which time the curd particles skrink and expel whey.

The "cooking" or "scalding" process then carried out on the curd, assists the shrinkage thereof and stops the activity of the culture bacteria. The temperature of the curd is raised throughout the cooking process and is carefully controlled. During the initial stages of cooking, the curd is very fragile and should not be subjected to heavy agitation. As the process continues, the curd strengthens and also requires to be cooked more rapidly and thus must be stirred to assist the heat transfer. The point at which agitation of the curd is increased being carefully monitored. When the curd is cooked, it is drained of whey and washed once or twice with chilled water, to reduce the acidity and firm up and cool the curd. The curd is then drained of wash water and is ready to be blended with a cream dressing to form a cottage cheese.

Although most forms of production of curd are broadly similar, the formulation and production of cream dressing may vary widely. The traditional "cream dressing" or "blending cream" is produced by mixing cream and skimmed milk to give a 14% to 16% fat dressing. Single cream or whipping cream may also be used for specialised higher-fat dressings. The cream dressing so produced is then blended with dry curd to produce a typical cottage cheese.

In recent years, lower-fat products have been produced, comprising a dressing containing only 4% to 5% fat which is mixed with the curd in the same ratios as are traditionally used.

The requirements for a cottage cheese dressing are that it has a good viscosity and a stable structure to ensure good blending properties and ability to maintain an attractive appearance throughout its sheif-life.

There are three methods, currently in use, of achieving the required viscosity for a cream dressing; (a) By selecting the fat level With a dressing having more than 14% fat, carefully controlled processing, such as homogenisation, can produce adequate viscosity. For example, single cream (18% fat) can be used as the cream dressing.

(b) By incubating a cultured dressing The dressing mix is first cultured and then may be incubated to set. For Example, soured cream generally has the same fat content as a single cream, but its viscosity is greater.

(c) The incorporation of so called stabilizers in the dressing to thicken the dressing.

Additives that simulate the properties of fat and, at the same time, give a more robust structure to the dressing may be added to the low fat dressing. In this way a dressing can be produced with a lower fat content and with a higher resilience to the shear, introduced in large scale manufacturing, than traditional cream dressing.

Methods (a) and (b) are applicable only to a restricted range of products, so that the third method (c) involving use of additives as stabilizers or thickeners has become widespread throughout the industry.

The required composition, taste and texture of the cottage cheese are achieved by blending appropriate amounts of curd and dressing, the mixing ratio being chosen according to the properties of the actual curd and dressing to be blended.

Cottage cheese typically comprises 4% of milk fat. Cream dressing of 12% to 16% fat are typically used, with the finished product comprising 30 to 40% dressing.

A low pH in the final product, typically pH 4.3 to 5.2, preferred pH 4.7 to 4.9, is desirable to give the product a mild lactic taste and also assists in the control of spoilage organisms.

This low pH may be achieved by the use of incubated dressing or by the addition of culture organisms to the finished dressing or blend. A limited range of organic and mineral acids may be added in the manufacture of cheese products. However, these must be declared as Additives on the packaging.

At pH values below 4.5, the product has a sharp, acidic flavour, is prone to 'syneresis' (wheying-off) and the curd may become hard and develop a powdery mouthfeel. High casein levels in the dressing may lead to gellation and setting of the product below pH 4.7.

The stabilizers currently incorporated in cottage cheese to achieve low fat content cheese, include Guar Gum (EEC No. E412), Locust Bean Gum (EEC No. E410), Carrageenen (EEC No.

E407) and Xanthan Gum (EEC No. E415).

Considerable concern has however been expressed as to the long term effects of imbibing such highly processed additives and there has developed considerable pressure on manufacturers to find an alternative method of achieving the requisite viscosity but which avoids the use of these materials.

The objective of the present invention is to provide a cottage cheese dressing of the following characteristics: (i) The preferred blending, viscosity and stability characteristics at a fat content of 12.5% or below.

(ii) A low pH, pH 4.7 to 4.9, that is stable throughout the product shelf-life.

(iii) The dressing will not set or gel at lower product pH.

(iv) Only contains dairy ingredients and so satisfies the requirements of an Additive-Free food.

According to the present invention there is provided a method of producing a dressing for use in the production of cottage cheese which comprises mixing together cheese whey and dairy cream to produce a first mixture containing from 4% to 16% w/w of fat, and adding to this mixture a whey protein in an amount to provide from 1 to 10% preferably 2% to 5% w/w of whey protein in the final mixture, homogenising the final mixture, subjecting the homogenized mixture to pasteurisation at elevated temperature and cooling the pasteurised mixture to below ambient temperature.

Preferably the whey used in the method of the invention is a cottage cheese whey. Typically such wheys have a pH of about 4.5 to 4.7 and a solids content of about 5% to 6% w/w. The cream used in the method of the invention preferably has a butterfat content in excess of 50% w/w typically 52% w/w. The bufferfat content of the first mixture is typically 12% to 14% w/w.

The whey protein used in the method of the invention may be added in the form of a whey protein concentrate preferably a concentrate obtained by ultrafiltration techniques. Thus a 75% protein concentrate may be used typically in an amount of about 3% w/w based on the weight of the first mixture to which it is added. Preferably a 55% protein concentrate is used to give a whey protein content in the dressing of from 1% to 6% w/w, preferably 2% to 5% w/w.

Salt (NaCI) may also be dispersed in the dressing of the invention if desired to assist in achieving even distribution of salt in the cottage cheese produced using the dressing but is not an essential ingredient of the dressing.

The final mixture prior to homogenising may have a pH of from 4.7 to 5.2 and preferably from 4.8 to 4.90 and a total solids content of from 18% to 24% w/w, preferably from 19% to 21% w/w. Prior to homogenisation the final mix may be warmed to a temperature of about 10 C to 13"C for example by passage through a heat exchanger. The warmed final mixture may be homogenised, for example single stage at 2000 to 3000 psi, preferably 2500 to 2700 psi.

Pasteurisation may be effected at a temperature of 85"C for 30 seconds followed by cooling to a temperature of 4"C to 50C.

The viscosity of the dressing may be 5 to 50 , preferably 30 to 50 as measured using a 15 s.w.g. torsion wire viscometer and 2.80 cm bob. Storage of the dressing for 12 to 24 hours under refrigeration increases the initial viscosity.

The invention will be further illustrated by reference to the following examples: EXAMPLE 1 A dressing for typical cottage cheese Fresh cottage cheese whey (5.6% total solids w/w) was mixed with raw cream (52.0% butterfat) to produce a mix of 12.5% w/w fat. To this mix was added 4.0% w/w 55% whey protein powder and 2.55% w/w salt, i.e. the full mix composition was: % w/w Cottage Cheese Whey pH 4.61 69.45 Raw Cream 24.00 55% Whey Protein Powder 4.00 Salt 2.55 100.00 The final mix was then warmed to 32"C, homogenised (single stage) at 2,700 psi, then pasteurised at 80"C (+ 1 C) and held for 45 seconds, before cooling to 8"C and filling into chilled storage tanks.The equipment used was standard APV Paraflow HX plate heat exchanger, Manton-Gaulin Single Stage Homogeniser and Esko jacketted agitated storage tanks.

The finished dressing had the following composition: % w/w Fat 12.25 Total solids 22.95 Salt 2.36 pH 4.82 Viscosity 35 EXAMPLE 2 A dressing for Lower Fat Cottage Cheese Fresh cottage cheese whey (4.8% total solids w/w) was mixed with soured cream (pH 4.74, 18.1% fat w/w) to produce a mix of 5.01% w/w fat.

To this mix was added 3.95% w/w Export Grade Whey Powder and 5.0% w/w of 75% Whey Protein Powder plus, 2.55% w/w salt, i.e. the full mix composition was: % w/w Cottage Cheese Whey 66.00 Soured Cream 25.00 Whey Powder 3.95 Whey Protein Powder 5.00 Salt 2.55 The final mix was then warmed to 32"C, homogenised (single stage) at 2,700 psi, then pasteurised at 80"C (+ 1 C) and held for 45 seconds, before cooling to 7"C and filling into chilled storage tanks. The equipment used was standard APV Paraflow HX plate heat exchanger, Manton-Gaulin single stage homogeniser and Esko jacketted agitated storage tanks.

The finished dressing had the following composition: % w/w Fat 4.85 Total Solids 20.08 Salt 2.58 pH 4.85 Viscosity 15

Claims (7)

1. A method of producing a dressing for use in the production of cottage cheese which comprised mixing together cheese whey and dairy cream to produce a first mixture containing from 4% to 16% w/w of fat, and adding to this mixture a whey protein in an amount to provide from 1 to 10%, preferably 2% to 5% w/w of whey protein in the final mixture, homogenising the final mixture, subjecting the homogenized mixture to pasteurization at elevated temperature and cooling the pasteurized mixture to below ambient temperature.

2. A method as claimed in claim 1 in which the whey is a cottage cheese whey.

3. A method as claimed in claim 1 or 2 in which the whey protein is added in the form of a whey protein concentrate obtained by ultrafiltration of clarified whey.

4. A method as claimed in claim 3 in which the concentrate is a 55% whey protein concentrate.

5. A method as claimed in claim 4 in which the concentrate is added in an amount to provide a whey protein content in the dressing of from 1 to 6% w/w.

6. A method as claimed in claim 5 in which the whey protein is present in the dressing in an amount of from 2 to 5%.

7. A method as claimed in claim 1 substantially as hereinbefore described in any one of the Examples.