FI57687B - FOER FARING FOER FRAMSTAELLNING AV EN MJOELKBASERAD DRYCK ELLER MOTSVARANDE - Google Patents

Description

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Patent · och registerstyrelsen '' AnaMun utiigd och uti. * Krifun pubiic «r * d 30.06.80

_ (32) (33) (31) Pyy * · »* • Tuoikau» —e ^ ird priont «t 07.Ol.7U

England-England (GB) 67U / 7U

Proven-Styrkt ~ (71) Unilever N.V. , Burgemeester s'Jacobplein 1, Rotterdam, The Netherlands

Holland (NL) (72) Peter John Argyle, Harpenden, Hertfordshire, Neil Brine, Stevenage, Hertfordshire, England-England (GB) (7U) Leitzinger Oy (5U) Method for making a milk-based drink or the like -Förfarande för framställning av en mjölkbaserad The present invention relates to a process for preparing a milk-based beverage or the like.

Many dairy products are made by acidifying milk to coagulate casein and other precipitating milk proteins and impart the desired flavor to the product. The acid payment is usually performed with lactic acid bacteria, such as yogurt microorganisms, and the milk, which may be whole milk or skim milk or mixtures thereof, or may be reconstituted from dried or concentrated products, is heated before and / or after the acid payment. An initial heating step can be used to pasteurize the milk to ensure that a few other organisms are present when the acidification is performed bacteriologically. It also promotes the coagulability of certain milk proteins that would otherwise tend to remain dissolved during the acid payment step.

The heat treatment can be performed on the acidified products as an additional step or as an alternative step in the final pasteurization step, with the aim of eliminating both acidifying organisms and possibly infections that could cause 57687 2 contamination. In any case, there is a separation of whey in the product due to the shrinkage of the cheese mass caused by the heat treatment in the product, as evidenced by the removal of some aqueous liquid from the product and the thinning of the base mass of the product. The dense, compressed curd particles formed during the last heating settle rapidly and also give the product an undesired granular structure. The importance of post-acid heat treatment, which is intended to prolong the shelf life of products based on yoghurt or other acidified milk beverages, is therefore severely limited when a mass-like, thickened but soft product is desired. Heat treatment at this stage is not possible when the product is desired to contain live, acidifying bacteria.

Water-retaining thickeners, such as edible stabilizing gums, have been added to these products to retain the aqueous component during and after the post-acid heat treatment, but such additives are not permitted in all cases. In addition, they are undesirable because they tend to cause other unfavorable structural properties to the products.

The above disadvantages can be avoided by the process according to the invention, characterized in that undenatured whey is added to increase the total whey content of the product to at least 1.5% by weight, preferably 3 to 6% by weight, and to provide at least 1: 4 by weight of undenatured whey and casein before heat treatment to denature the bulk of the whey present, thereby stabilizing the product against whey separation.

Undenatured whey: The casein ratio is best increased by adding undenatured whey to the milk before the heating step. In particular, it is recommended to use milk as a starting material. When artificial casein / whey protein mixtures are used instead, the casein must be in the micelle form found in the milk.

The invention is suitable for the preparation of all dairy products treated with bacterial cultures or acidified in addition to milk beverages, for example sour cream, flavored sour cream sauces, cheese. .> Λ 3 57687 sauces and yoghurt, which, unlike conventional cheese products, require a large product to retain most of the aqueous matter. However, the invention can be applied in particular to the preparation of dairy products flavored with acid-forming bacterial cultures, in particular yoghurt bacterial cultures.

The coagulated products obtained by the invention can be heat-treated to pasteurize them or left untreated, whereby the acidifying bacteria remain alive in the product. In the latter case, it is "essential to adjust the ratio of undenatured whey protein to casein and then heat treat the milk to denature the whey protein prior to the acidification step. In the former case, although to be performed afterwards, i.e. after cooling, either before or after the acid addition step, and the final heat treatment is then essential. In either case, the substantial heat treatment must be sufficient to denature at least a portion of the undenatured protein in the undenatured whey present. It is recommended to perform the step at about 90 ° C. Under pasteurization conditions, whey protein is usually denatured to some extent, but in accordance with the invention, it is desirable to operate under heat treatment conditions where whey protein denaturation is at a maximum. Such conditions can be much more severe than conditions sufficient for pasteurization, and for example, times of 5 to 30 seconds at 70 to 100 ° C are recommended, although times as small as a second may be sufficient.

A suitable whey protein to increase the ratio of undenatured whey to proteinase can be obtained, for example, by reverse osmosis, gel filtration and dialysis. It may contain part of the denatured whey protein, although its presence in the additive should be avoided as much as possible. Whey is best subjected to a concentration treatment by removing at least part of the water, and whey powder is preferred. Liquid concentrates should preferably contain a total of at least 5% by weight of undenatured protein.

It is believed that although milk casein, when coagulated, is largely responsible for thickening the product, whey separation is prevented by the presence of a sufficient amount of whey protein denatured in the presence of casein. Whey protein denatured in the absence of casein apparently has no stabilizing effect on the product. At least 1.5% whey protein is needed, at least in the absence of fat, which itself is somewhat resistant to whey separation, and therefore in conventional products made from skimmed milk with a fixed whey casein-protein ratio, this corresponds to a total protein content of 6 .5%. By increasing the ratio of undenatured whey protein to casein, for example, using a whey source as part of the amount of whey protein required to form a physically stable product, the amount of casein can be reduced to give a thinner end product. In addition, although in the past the protein content of milk has been increased by adding whey protein in the preparation of coagulable products, this has so far been substantially denatured and thus does not provide a stabilizing effect against whey separation. The addition of any undenatured whey protein that may already be present provides a substantial anti-whey effect of the whey of the invention without increasing too much viscosity. The undenatured whey protein source should also contain relatively little casein to minimize the increase in viscosity in the product.

When an unpasteurized product is desired, sufficient undenatured whey protein is preferably present prior to heat treatment so that the minimum amount of total whey protein in the product is about 1.5% by weight, preferably 1.5-3% by weight, to obtain a product in which whey differs sufficiently in practice. When the product is pasteurized, the total protein content should be at least 4-4.5% by weight in order to clearly prevent whey separation, but good results have been obtained between 3 and 6%. In addition, if the pasteurized product is to be granular, the whey protein to casein weight ratio should be at least 1: 2, especially 1: 1, compared to a 1: 4 ratio of natural milk, the amounts being the weight ratios of undenatured whey protein to total casein. When the product is too thick and viscous to drink, such as yogurt, somewhat higher concentration values and ratios are preferred. In all cases, the amount of undenatured whey protein added is to some extent a function of the amount already present in the milk. The added whey protein, which is eventually denatured, improves the stability of the product without increasing its viscosity too much. The presence of fat or other components that promote stability reduces the amount of whey protein required. By means of the invention, the anti-whey effect of whey is achieved even in unpasteurized, skimmed milk products without producing products that are too thick and viscous.

The maximum amount of undenatured whey protein that can be added in accordance with the invention is not critical. The amount of casein in the final product should be at least 1.5% by weight, preferably 1.5-3%, in order to obtain satisfactory coagulation in the task. However, within these limits, a large number of products can be obtained in which, depending on the total milk protein content, whey separation is prevented.

The milk used in the method of the invention may be from various sources. Cow's milk and lactation products from most animals, including donkey's milk, sheep's milk, goat's milk and buffalo's milk, can be used. The milk may be whole cream or partially skimmed, and reconstituted milk powder may also be suitable, the protein content of which may be increased.

Coagulation can be accomplished by culturing lactic acid bacteria or by chemically added acid. Suitable bacteria include yogurt bacterial cultures and, in general, acidophilus bacteria. Kefir and rubber cultures can also be used. When the starting material is an artificial mixture instead of milk, it may be necessary to ensure that the medium contains the necessary factors for growth, such as sugar.

Useful chemically added acids include mineral acids and suitable organic acids.

s *

The protein content of milk and milk products, both denatured and undenatured, can be measured using a "Promilk" analyzer, marketed by Foss Electric Ltd, Hillerod, Denmark. The degree of denaturation can be measured by determining how much undenatured whey protein remains dissolved at pH 4.6, where both casein and denatured whey protein coagulate. These can be removed by centrifugation of serum containing undenatured whey protein.

Example 1

A cherry-flavored, fat-free pasteurized yoghurt drink was prepared from the following ingredients:

Ingredient Weight parts

Water 871.2

Skimmed-milk powder to give 4.8 parts of whey protein + 17.4 parts of casein 60.0

Whey powder so as to give 25 parts of undenatured whey protein 38.8

Starting culture of yoghurt bacteria in skimmed milk (gives 0.2 parts whey protein + 0.8 parts casein 30.0 1000.0

Sugar 60.0

Cherry Flavor Concentrate 30.0

Undenatured whey protein: casein ratio 29.8: 18.2

Undenatured whey protein: total casein ratio 1.63: 1

Total protein content 4.4%

The skimmed milk powder was dispersed in water at 20 ° C and the liquid was heated at 90 ° C for 15 minutes. The whey powder was dispersed in the liquid when cooled to 60 ° C.

The mixture was then further cooled to 45 ° C, a yoghurt bacterial culture was added and the temperature was maintained at 45 ° C until the pH dropped to 4.0. The resulting protein mass was decomposed by stirring and sugar and fruit flavor concentrate were added.

The finished mixture was kept at 90 ° C for 10 minutes, homogenized at 200 atmospheres, packaged at 75 ° C, cooled and stored at 10 ° C.

A similar product was prepared which contained fat and to which more skimmed milk powder had been added to obtain a thicker product. 75 parts of skimmed milk powder, 20.8 parts of cream (corresponding to 10 parts of milk fat), 31 parts of whey powder (corresponding to 20 parts of undenatured whey protein) and water were obtained to give 1000 parts as follows:

The cream was homogenized in reconstituted skimmed milk powder at 150 atmospheres and kept at 90 ° C for 15 minutes. After cooling to 60 ° C, whey powder was dispersed in the mixture and preparation was continued as above. The finished, fruit-flavored beverage contained 4.5% protein with a whey protein: casein ratio of 1.16: 1.

Neither product showed whey separation and remained microbiologically stable and granular-free when stored at 10 ° C for 3 weeks.

In contrast, comparative experiments using the same preparation method without adding undenatured whey protein and adding denatured whey protein yielded products that were granular and had strong whey separation within 24 hours.

"" Example 2

An orange-flavored, fermented pasteurized milk drink was made from the following ingredients:

Ingredient Weight parts

Liquid milk containing 28.8 parts fat, 24 parts casein and 6.7 parts undenatured whey protein 959

Whey powder containing 20 parts of undenatured whey protein 31

Milk 10 1000

Sugar 30

Orange concentrate 30

Undenatured whey protein: total casein ratio 1.06: 1 Total protein content 4.8%

The milk was homogenized at 150 atmospheres and 60 ° C to disperse its fat content and kept for a further 30 minutes at 85 ° C. After cooling to 60 ° C, the whey protein was dispersed in milk. After further cooling to 30 ° C, the mixture was inoculated with diatomaceous earth and allowed to ferment at this temperature until the pH was 4.4.

Sugar and orange extract were added, mixed with a diatomaceous earth mixture containing coagulated protein and heated to 90 ° C, held at this temperature for 10 minutes, homogenized at 200 atmospheres at 57687 8 and finally packaged at 75 ° C, then stored at 10 ° C.

This product was pleasantly mild in taste and granular when examined after 3 weeks of storage. During this time, no whey resignation was seen. Nor had it been infected by microorganisms.

Example 3

A series of non-fat, strawberry-flavored unpasteurized yogurt drinks were prepared by gradually increasing the concentration of skimmed milk powder and adding correspondingly smaller amounts of whey protein powder to give products with increased viscosity but a constant whey protein content of 1.7%. The skim milk powder and the whey protein powder containing undenatured whey protein were dispersed in a sufficient amount of water at 20 ° C to obtain a premix of 1000 parts by weight which did not contain the starting culture. The premix was then heated for 15 minutes at 90 ° C to pasteurize the raw materials and denature the whey protein.

The mixture was cooled to 45 ° C, 30 parts of a yoghurt bacterial culture were added and the temperature was maintained at 45 ° C until the pH was 4.0. The resulting protein mass was decomposed by stirring and 60 parts of sugar and 120 parts of strawberry charcoal were added. The finished mixture was then cooled to 2-5 ° C, homogenized at 200 atmospheres and packaged, without the temperature rising above 10 ° C at all.

In none of these products was whey detached when stored for 2 weeks at 5-10 ° C. Further details are given in Table 1.

table 1

Parts by weight per 1000 Protein in the finished product

The product forms a premix _. ..

- - Weight -% _ Whey _ratio

Peeled _ Hera- ^ ___4. . „Casein milk meal powder * K? -S-el-lnl Total3k - A 75 (6) 18 (11) 1,9 3,4 0,79 B 90 (7) 16 (10) 2,3 3,8 0, 65 C 120 (9, 6) 12.7 (7.7) 3.0 4.5 0.50

Sfc Weight parts of undenatured whey protein in parentheses.

. · <1

Claims (4)

57687 9 The viscosity of these products increased substantially between products as the casein content was increased. The product, which was prepared from 210 parts of skimmed milk powder without adding any whey powder in 1000 parts of premix to give a casein content of 5.2% and a whey protein content of 1.5% in the finished strawberry flavored product, also did not whey during the same storage period, but was substantially thicker than in Table 1. Products. A process for preparing a milk-based beverage or the like, in which casein is coagulated by acidification, preferably by lactic acid-forming bacteria, and the mixture is heated to about 9090 ° C sufficient to denature the whey protein present, before and / or after coagulation of the casein, known that undenatured whey is added to increase the total whey content of the product to at least 1.5% by weight, preferably 3 to 6% by weight, and to provide a weight ratio of undenatured whey to casein of at least 1: 4 before heat treatment of the main whey present to denature, thereby stabilizing the product against whey precipitation. Process according to Claim 1, characterized in that undenatured whey concentrated by ultrafiltration is added. Method according to Claim 1 or 2, characterized in that the bacterial culture is a yoghurt bacterial culture. Method according to one of Claims 1 to 3, characterized in that the coagulation takes place after the heating steps to form a product containing live bacteria.