DE3146198A1 - Process for the preparation of yoghurt with reduced lactose content - Google Patents

Abstract

Lactose-reduced yoghurt is prepared (if appropriate with the use, or concomitant use, of fungal lactase) by adding the lactase simultaneously, or virtually simultaneously, with the starter culture.

Description

Method of making yogurt using

reduced lactose content The present invention relates to a process for the production of low-lactose yoghurt from milk and milk solids in which the raw materials are mixed with the addition incubated by lactase and a starter culture and then cooled.

Yoghurt is a product made from heated and homogenized, Milk standardized in terms of dry matter and fat content, usually with addition of skimmed milk powder and / or hydrocolloid is produced by the thus obtained Mixture with the help of a suitable acid alarm culture, mostly from Lactobacillus bulgarleus and Streptococcus thermophilus, by biological acidification to one pH of 496 - 491 is brought.

It is well known that yogurt consumers prefer products that which are not acidic, have a creamy structure and during storage have deposited fine whey. The use of yogurt is because of its taste and its presumably regulative influence on bowel movement To meet the demands of the consumer, the manufacturer requires special technological Measures - such as heating the milk with holding time, use of slime-forming Cultures, incubation of yoghurts when the incubation temperature drops, addition of skimmed milk powder and / or hydrocolloids, storage at low temperatures - required to maintain consistency and to positively influence the taste of the end product.

Yogurt is usually made using the following additives.

Milk with a standardized fat content of up to 100% skimmed milk powder 0 - 3% hydrocolloids O - 1.7% common acid starter culture (see above) 1 - 3% fruits, Fruit preparations O -18% flavors, spices A common manufacturing process for yoghurt is explained below, with temperature and quantity, as well as the order of the process steps are not mandatory, as they depend on the manufacturing process and thus can vary according to the type of end product desired.

The cleaned milk is adjusted to the required fat content by means of a separator set. By adding skimmed milk powder and / or hydrocolloids, the Dry matter enriched to improve the consistency and texture of the yogurt. After the so-called "standardization" of the milk, it is homogenized (200 bar) and heating (900C / 30 sec). The yoghurt milk treated in this way is brought to the incubation temperature cools and inoculated with 1 - 3% of the acid alarm culture. When making a solid natural yoghurt, the inoculated milk is filled into cups and poured into incubated this; When making fruit yoghurt, the milk is incubated in the tank and after reaching the desired pH value, fruits or aromas are added, the mixture stirred, heated, filled into beakers and cooled. Incubation takes place in generally at temperatures around 40-450C, until the desired pH value of 4.6 to 4.1 is achieved. The incubation time varies depending on the temperature and activity of the acid alarm clock used between 2.5 to 4 hours.

It has already been proposed to accelerate the fermentation of lactose in yogurt production and the associated reduction in the lactose content To use cactase. Lactase breaks down lactose into glucose and galactose and thus anticipates that digestive step that is not possible for people with lactose intolerance.

The lactase treatment of milk to make yogurt has been around since Known for a long time and already described in some publications. However the lactose cleavage processes described in the published work could be used for reasons of inefficiency and additional risk factors in practice do not prevail and therefore remain only of scientific interest. From the present work it can be inferred9 that the milk before the actual Yoghurt production must be treated with lactase in an upstream stage. This is done at temperatures of 300C and treatment times of 2 - 3.5 hours (Thomasow and Elostermeyert Deutsche Milchwirtschaft 38/1977; Dana M.

Gyuricsek and Marvin P. Thompson, Cultured Dairy Products Journal5 Aug. 1976) or at 40c overnight (V.S. O'Leary and I.H. Woychlk, Journal of Food Science, Vol. 41, 1976, 791).

After the lactose has been broken down, the milk treated in this way can then be used to make yoghurt be used.

This so-called pre-hydrolysis of the milk is for the following reasons not practical: - Through the additional treatment stages The production process of milk is delayed by the amount required for the lactose breakdown Times (see above).

Time savings of 30 - 50 minutes during incubation, which are as a result of the lactase treatment of the milk, the real time expenditure is the "Prehydrolysis" opposite, so that there is no real shortening of the production.

- Milk is an ideal nutrient medium for microorganisms and favors their growth especially at temperatures of 30-400C. A pre-treatment of the milk at the temperatures just mentioned for a period of 3 - 4 hours the risk of an increase in the number of germs and the possible microbial spoilage as a result.

- The lactase treatment carried out (during storage at 300C) the milk requires additional energy costs, since the milk lasts for a few hours Reaction temperature must be maintained.

It has now been found that an upstream lactose treatment can be dispensed with and the addition of lactase to the substrate is simultaneous or almost simultaneous can be done with the addition of the acid alarm culture. In particular, the Adding lactase immediately before incubation ensures sufficient lactose breakdown be achieved. For this purpose, the lactase is put into the finished product at the incubation temperature preheated, yogurt milk introduced. In order to avoid clumping (e.g. when entering powdered lactase), the lactase is expediently in mixed with a smaller volume of milk and only then added to the total mixture. Then add the required amount of alarm clock mixed in and proceed in the usual way. The effect usually occurs immediately, so that the lactic acid bacteria are already sufficient in the initial phase Glucose is available as an energy source.

It was also found that by the method according to the invention the use of fungal lactase or a mixture of fungal lactase / yeast lactase is more variable percentage composition is possible, i.e. the one previously only used If desired, yeast lactase can be produced in whole or in large part by the even lower pH values of active fungal lactase are replaced. The ratio of fungal lactase / yeast lactase depends primarily on the degree of lactose breakdown desired. The application takes place as already described.

Due to the different pH optima of yeast lactase and fuhgallactase the degrees of hydrolysis differ considerably after incubation. In the event of a pure yeast lactase will result in high glucose and galactose values after incubation obtain; the milk sugar is almost broken down. When using fungal lactase if the glucose and galactose content after incubation is lower than the residual lactose content higher. The lactose breakdown takes place here during storage at low temperatures continued because fungal lactase have their pH optimum at pH 3.5-5.0.

The addition of lactase according to the invention has made it possible To control the glucose-galactose and lactose content in the end product yogurt, since the Composition of the added lactase preparation can be varied individually.

The application rate of the lactase is normally of the order of magnitude from about 50 - 300 mg / l milk to be treated. Depending on the activity of the However, the dosage of the enzyme preparation can deviate considerably from these values. The yeast lactase used had an activity of 25,000 LU / g, which Fungal lactase 10,000 LU / g (LU s Lactaseunit).

The shortening of the incubation time is with the addition of pure yeast lactase within the given dosage guidelines, it is independent of the dose, i.e. it is independent on the amount of enzyme. Differences are only found in the degree of final hydrolysis.

The method according to the invention makes it possible to achieve those indicated above Disadvantages of the previously proposed use of lactase due to its practicality Eliminate use and the manufacturing process of low-lactose yogurt to make it economical. The production process is controlled by the addition of lactase immediately before incubation neither delayed nor disturbed, and that caused by the shortening The time saved during the incubation period can be used to the full.

Example 1 (prior art; production of solid natural yoghurt without addition of lactase) 1 liter of commercially available, homogenized whole milk with a fat content of 3.5% was warmed to 450C in a water bath and mixed with 30 g of skimmed milk powder After the skimmed milk powder had dissolved without lumps, it was added of 30 g of a commercially available acid starter culture. According to the homogeneous distribution of the acid alarm in the milk, this was filled into cups in 100 g portions and acidified at a temperature of 43 ° C to a pH of 4.6.

The incubation time was 200 minutes. The yogurt portions were then added cooled down to 5 0C with the help of a water bath. After that, the yogurt portions were stored in the refrigerator at 50C. After cooling - after the incubation - and After 14 days of storage, the analytical determination resulted in those in the table 1 values shown.

Table 1 according to the lactose [g / 100g yogh 3.00 galactose [g / 100g yogh.] 1.25 glucose [g / 100g yogh.] --- 0.01 OSPg 40 60 total acid [g / 100g yogh.] 0.870 1.23 The analytical methods used are in connection with the Examples explained.

Example 2 (Production according to the invention of solid natural yoghurt with the addition of yeast lactase) 1 liter of commercially available, homogenized whole milk with a fat content of 3.5% was warmed to 450C in a water bath and stirring mixed with 30 g of skimmed milk powder. This was followed by the addition of 200 mg powdered yeast lactase (Hydrolact S 250). After getting the skimmed milk powder and the lactase had dissolved lump-free, 30 g of a commercially available one became Acid alarm clock added. After the acidic starter is homogeneously distributed in the milk this was filled into cups in 100 g portions and kept at a temperature of 430C acidified to a pH of 4.6. The incubation time was only 175 minutes. The yoghurt portions were then cooled in a water bath at 5 ° C for 1 hour. The yoghurt portions were then stored in the refrigerator at 5 ° C.

After cooling - after the incubation - and after 14 days The analytical determination resulted in the storage duration as shown in Table 2 Values.

Table 2 according to the lactose storage after incubation [g / 100 g yogh.] 0.793 galactose [g / 100 g yogh.] 2.17 glucose [g / 100 g yogh.] 1.74 1.43 0511 40.0 58 total acid [g / 100 g yogh.] 0.870 1.23 Example 3 (according to the invention Production of solid natural yoghurt by adding a mixture of yeast / fungal lactase in a ratio of 1: 1).

The milk was pretreated and the yoghurt was made corresponding to Example 2. Instead of 200 mg of yeast lactase, a mixture of 100 mg Yeast lactase and 100 mg fungal lactase (Amano-F) added.

The analytical results (obtained as in Example 1) are in the following table: Table 3 after storage after incubation Lactose tg / 100 g yogh.) 0.750 galactose [g / 100 g yogh.) 2952 glucose [g / 100 g yogh. ] 1.29 1.60 oSH 41.0 59 total acid [g / 100 g yogh.) 0.880 1.27 Example 4 (inventive Production of solid natural yoghurt by adding fungal lactase) The pretreatment the milk and the production of yoghurt took place according to Example 2. Instead of 200 mg of yeast lactase was added to 200 mg of fungal lactase.

The analytical results (obtained as in Example 1) are in the following table compiled: Table 4 after storage after incubation Lactose [g / 100 g yogh.] 0.300 Galactose [g / 100 g yogh.] 2.64 Glucose [g / 100 g yogh.] 0.97 1.74 OSH 40.0 59 Cesamtic acid [g / 100 g yogh.] 0.865 1.22 The following analysis methods were used - To prepare the sample, 2 g of yogurt (homogeneous average sample) diluted with distilled water and made up to a volume of 100 ml.

After thorough mixing and subsequent centrifugation the clear supernatant was based on glucose, galactose, lactose, D-lactic acid, L-lactic acid and citric acid investigated.

- The total acid listed in the examples is quantitative composed of L, lactic acid + D-lactic acid + citric acid.

- The tests of acids and sugars were carried out on enzymatic Ways (method book of enzymatic food analysis, Boehringer Mannheim. Self-published by this company).

Degree of acidity according to Soxhlet-Henkel (° SH) The determination of the degree of acidity in yoghurt was carried out according to the standard dairy method No. 6, 1963, see Handbook of Food Chemistry, Volume III, Part 1, p. 237, Springer-Verlag, Berlin-Heidelberg-New York, 1968).

Claims (7)

Claims 1. Process for the production of lactose-reduced Yoghurt, characterized in that the addition of lactase to the substrate is simultaneous or takes place almost simultaneously with the addition of the starter culture. 2 The method according to claim 1, characterized in that the lactase immediately before incubation in the finished, preheated to operating temperature Brings in substrate. 3. The method according to any one of claims 1 or 2, characterized in that that the lactase is fungal lactase, a mixture of fungal and yeast lactase or yeast lactase used alone. 4. The method according to any one of the preceding claims, characterized in that that about 50-300 mg of lactase per liter of the milk to be treated are used. 5. Method for controlling the glucose / galactose ratio and the lactose content in lactose-reduced yogurt using fungal lactase or a Mixture of fungal and yeast lactase. 6. Use of fungal lactase or a mixture of fungal and yeast lactase for the production of lactose-reduced yoghurt. 7. Lactose-reduced yogurt, characterized in that it is after the method of any one of claims 1 to 5 was obtained.