DD234786A1 - PROCESS FOR OBTAINING PROTEINS WITH IMPROVED DISPOSAL PROPERTIES - Google Patents

Abstract

The invention relates to a method for obtaining proteins with improved Verschadeumungseigenschaften from plant and / or animal, mainly globulins, prolamins, glutins or caseins containing raw materials and their workup products. According to the invention, the starting materials are first subjected to a mechanolytic degradation to a particle size of 25 mm and a relative molecular mass of the proteins from 10,000 to 50,000, and the finely ground products are dispersed in an aqueous medium, the undissolved portions are separated and the resulting solution is subjected to ultrafiltration. The products obtained in this way have excellent Verschaueumbarkeit, with high foam density and foam stability. They are advantageous raw materials for the production of food foams.

Description

According to KINSELLA (1983), amino acid sequence and disposition, molecular size, molecular shape, conformation and flexibility, charge and hydrophobicity of the proteins influence their foaming behavior in food systems.

With regard to foaming, the following operations should be considered. As a result of their surface-active action, proteins in aqueous solutions reduce the surface tension more or less rapidly. This allows the formation of stable air bubbles when whipping. The proteins diffuse to the newly formed interface of air and water, accumulate there and lower the surface tension. The molecules are unraveled at the interface: the polypeptide chains unfold and amino acid side chains are uncovered. Then there is a Reorientierung, where the polar groups

Align towards the water side.

As a result, an initially monomolecular film is formed around the bubbles. Responsible for this are both hydrogen bonds and electrostatic bonds as well as hydrophobic interactions. With a second molecule layer, a solid, elastic protein network is created in this way. However, aggregation and coagulation of the proteins as well as gas diffusion and gravity-induced drainage of the interlamellar water cause rupture of the protein capsules and collapse of the foam after some time

 Various factors influence the formation and stability of protein foams. The most important are:

the solubility of the proteins,

the rate of superficial tension decrease and protein diffusion to the interface of air and liquid,

the rate and extent of molecule unfolding, as well as the reorientation and association of the polypeptides,

the viscosity of liquid and interfacial film,

bubble size, film elasticity and thickness and, associated with that, gas diffusion as well

- the balance of the attraction and repulsion forces and the pressure of the quiescent fluid.

Although the phenomenon of foam formation seems to reflect the molecular conditions and processes described above, and the most important influencing factors are known, the progress achieved in recognition does not allow previously uncommon proteins to be directed and specifically modified into alternative foaming agents or improved in their effectiveness. All known technical attempts to meet the molecular requirements by fractionating, denaturing, derivatizing, partial hydrolyzing and / or additives have empirical character. Egg white is the most commonly used protein raw material for the production of food foams and especially of foam sugar products. However, the foam properties of egg white are subject to considerable natural variations. This has a detrimental effect on the quality of the foam products, especially in continuous foaming technologies. There are also hygienic problems. Therefore, instead of Frischeiklar today mostly spray-dried and pasteurized egg white powder is used in which the glucose contained in the egg white and the due to improper separation of egg white and egg yolk-related traces of fat have been removed enzymatically. Nevertheless, fluctuations in the product quality and the foam properties can not be excluded, so that when using egg white powder in the production of food foams again and again batches occur.

This, as well as economic considerations that make a partial or total substitution of egg white by comparatively cheaper and safer proteins appear desirable, and moreover, the search for proteins that have better foaming properties than the known products, and in particular egg whites, justify the need for the development of Process for obtaining highly efficient foamable and alternative protein substances.

Ways to influence the foaming properties of proteins by derivatization (acetylation, succinilination), denaturation (temperature and pH change) and interaction with other substances (sodium chloride, carboxymethylcellulose, polyvalent metal ions, triethyl citrate) are described by MUSCHIOLIK and SCHMANDKE (1981, 1984) ). PAQUET (1981) has specifically described ways to improve the foam properties of whey proteins, with the aim of using them as egg white substitutes. After that, especially a, leading to weak protein denaturation temperature pH treatment causes an improvement in the foam properties.

Furthermore, it is known that the foam properties of proteins can be improved by enzymatic hydrolysis (DE-OS 3 118 798 A1 / US Pat. No. 3,674,501). Furthermore, a two-step process has been described in which sequential addition of chemical (acidic or alkaline) and enzymatic (by pepsin) hydrolysis foamable proteins are obtained (US Pat. No. 3,814,816).

In another patent, a method is reported with which it is to succeed in spezieilen well expandable protein fractions from soybean meal by extraction by means of an aqueous medium / separation of the solids from the extract, ultrafiltration or diafiltration of the extract and enzymatic party hydrolysis of the proteins dissolved therein to produce a degree of hydrolysis of 1 to 8 (DE-OS 3,118,798 A1).

The methods of chemical derivatization and hydrolysis as well as the denaturation and interaction of proteins with other substances have the general disadvantage that they are associated with a high procedural complexity and usually also with the removal or harmlessness of the chemicals used. In addition, the utility of the resulting products is limited due to the blocking of essential amino acids with respect to their use for nutritional purposes. In the processes of enzymatic hydrolysis there is also the risk of the formation of sensory adverse substances, eg. B. of bitter peptides. Moreover, such processes always include the need for enzyme activation, which adds additional processing overhead.

Although the process of the mechanolytic treatment of proteins does not suffer from these disadvantages, drastic improvements in the foam properties are not achieved in every case, so that it is not always possible to calculate with material-economical and special sensory effects (lightweight foams).

Object of the invention

Accordingly, the object of the invention is the development of a process, the use of which, while largely avoiding chemical agents and enzymes, provides the possibility of expanding the range of foamable proteins and of producing highly effective foaming agents. The invention has for its object to provide process conditions for the treatment of proteins, among which they are modified so that their foaming properties are significantly improved without any nutritional and sensory impairments occur.

Explanation of the essence of the invention

The inventive method for obtaining proteins having improved foaming properties of plant and / or animal, mainly globulins, prolamins, glutins or caseins containing raw materials and processing products thereof, preferably in the form of protein isolates, protein concentrates and protein-rich flours is that the proteinaceous raw materials and / or work-up products thereof first a mechanolytic degradation, preferably by means of a ball or vibrating mill to a particle size <25, and a molecular weight of the proteins from 10,000 to 50,000 are subjected and that after dispersion of the finely ground products in an aqueous medium and subsequent Separation of the undissolved portions of the resulting solution is subjected to ultrafiltration and thereby the proteins are separated into fractions of different molecular size.

It has surprisingly been found that proteins with comparatively excellent foaming properties can be obtained by combining mechanolysis and ultrafiltration. When using only one of the two process steps, such first-class properties can not be achieved. The products obtained under normal use of the process are superior in terms of foam volume, foam density and in many cases also the foam stability Frischeiklar and egg white powder.

The inventive method is based on the finding that the mechanolysis due to destruction of the spatial structure in the interior especially of globular proteins are included and thus not effective, for foaming but crucial hydrophobic districts and amino acid groups are exposed that further hereby and by the parallel running partial degradation of the molecule increases the solubility and in particular the flexibility of the proteins and thus the diffusion to the air-water interface including the film formation are intensified as a further prerequisite for achieving good foam properties. It is also essential for the process that enrichment of the proteins which are particularly suitable for foaming is carried out by the subsequent ultrafiltration of the dissolved proteins, specifically by the selective use of membranes having different molecular retention capacities. It has been shown that there is a certain correlation between particle size and molecular weight (Table 1).

Table 1

Correlation between particle size (depending on the conditions of the mechanolytic treatment in a ball mill ') and molecular weight (after separation of the aqueous protein solutions in an ultrafiltration plant), illustrated by the example of a soy protein concentrate

Vers. No. mechanolytic treatment [hours] Particle size spectrum [%] <10 μηη <20 μηη <30 μηη <200 μσι molecular weight ² 10 000- > 50 000 50,000 1 0 <5 um _ _ _ 16 <10 000 12 83 2 3 10 100 _ 70 80 87 94 92 98 98 100 CJL 28 75 63 54. 70 9 25

1 Type 260.21, VEB Keramische Werke Hermsdorf;

Conditions of mechanolysis: porcelain balls, diameter 16 mm, filling ratio F = 3%, filling degree G = 40%, rotational speed u of the grinding drum 63 min "'

2 on the basis of the molecular retention capacity of cellulose acetate membranes η in an ultrafiltration plant at an excess flow rate of 12 l / min

As a further advantage of the process according to the invention, it has been found that, regardless of the state or degree of denaturation of the protein raw materials containing mainly globulins, prolamins, glutins or caseins, fractions are separated from which highly efficient foaming agents can be obtained by simple drying. In this way, proteins or protein substances which are inherently non-foamable or strongly denatured during the course of their production or processing and therefore likewise barely or not foamable can be provided with excellent foaming properties. This increases the usability of non-conventional or previously unavailable protein raw materials and expands the range of foamable proteins with highly effective alternative products. The improvement of the foaming properties of proteins is determined by the conditions of mechanolysis by means of ball or vibrating mills, i. H. through the grinding time, the grinding media diameter, the density of the grinding media, the ratio of the mass of the grinding media to the mass of the starting material filling ratio F [%]), the ratio of the total volume of the grinding container to the volume of the grinding media (degree of filling G [%]) and the rotational speed the grinding drum in ball mills and the amplitude of the grinding drum in vibratory mills and by the molecular retention capacity of the membranes used in ultrafiltration and controlled.

Surprisingly, it is inherent in the process according to the invention that practically all fractions obtained can be utilized (Tables 2 and 3). The full utilization of the protein raw materials used achieves a high process economy and reduces the environmental impact associated with many protein processing methods, e.g. B. by organically bound nitrogen or chemicals contained wastewater are avoided.

Furthermore, it is not insignificant for the process described according to the invention that the use of additives is largely dispensed with, which in turn has an advantageous effect on the process economy. The invention is explained in more detail by the following embodiments.

embodiments example 1

In each case 25 g of a commercially available soy protein concentrate (61.1% crude protein content) in a vibrating mill "Vibratom" (Siebtechnik GmbH, Mühlheim / FRG) at a filling level of 70%, a filling ratio of 2.5%, in the presence of porcelain balls with a diameter of 10 mm and with an amplitude of 2.0 mm for different lengths (20, 50 or 100 hours).

Thereafter, the foam properties of the mechanolyzed products according to WP A 23 G / 269 765 8 are determined (Table 2). The 50 hour milled preparation is further worked up according to Scheme 1 using cellulose acetate membranes with a molecular retention of 20,000 by ultrafiltration. After, done in a known manner drying fractions result with the documented in Table 2 foam properties.

Example 2

720 g of a commercial, precipitated with sulfuric acid casein (82.5% crude protein content) are in a ball mill type 260.21 (VEB Keramische Werke Hermsdorf) at a filling level of 50%, a filling ratio of 10% in the presence of porcelain balls with a diameter of 30 mm and at a speed of the grinding drum of 63 min. for ^{1 to} 10 or 100 hours, after which the 100-hour mechanoylated product is further worked up by ultrafiltration using cellulose acetate membranes with a molecular retention capacity of 10000. After drying in a known manner result fractions with the foam properties given in Table 3 (determined according to WP A23 G / 269 765 8).

Table 2

Protein content and foam properties of differently treated soy protein concentrates and fractions (13% solutions or dispersions)

protein product protein foam foam foam paragraph salary activity stability density 60 min [%] ¹⁾ [%] [%] [G / ml] [ml] ² »

Soy protein concentrate (commercial product) soy protein concentrate, 20 h mechanolyzed soy protein concentrate, 50 h mechanolyzed soy protein concentrate, 100 h mechanolyzed extract, spray dried residue, freeze dried residue, freeze dried, 20 h mechanolyzed retenate, spray dried filtrate, spray dried egg white egg white powder, dan. ancestry

61.1 0 - '- 0 61.1 1250 100 0.08 0.5 61.1 1 950 94 0.05 0 61.1. 1700 100 0.06 0 51.6 1850 100 0.05 0.5 65.1 1250 92 0.08 0.5 65.1 1500 93 0.07 0 44.8 2200 100 0.05 - 0 37.7 1 500 93 0.07 3 10.5 925 89 0.11 2 75.0 1 100 98 0.10

DN χ 6.25; ² 'based on 100 ml of foam

Table 3

Protein content and foam properties of differently treated casein and fractions (13% solutions or dispersions)

protein product protein foam foam foam paragraph salary activity stability density 60 min [%] . [%] [%] [G / ml] [Ml]

casein 82.5 250 0 0.40 15 Casein, 10 h mechanolysiert 82.5 400 0 0.25 12 Casein, 100 h mechanolysiert 82.5 900 80 0.11 5 Extract, spray dried 79.5 1050 85 0.09 3 Residue freeze-dried 83.7 550 67 0.18 7 Retenat, spray dried 85.3 1200 92 0.08 2 Filtrate, spray dried 72.2 600 '. ". 69 0.17 6

Claims (7)

Invention claim: 1. A process for obtaining proteins having improved foaming properties from plant and / or animal, preferably globulins, prolamins, gluteline or caseins containing raw materials and from work-up products thereof, preferably in the form of protein isolates, protein concentrates and protein-rich flours, characterized in that the proteinaceous raw materials and / or the workup products thereof are first subjected to a mechanolytic degradation, preferably by means of a ball or vibration mill to a particle size of 25 microns and to a molecular weight of the proteins of 10,000 to 50,000, and that after dispersing the finely ground products in an aqueous Medium and subsequent separation of the undissolved portions of the resulting solution is subjected to ultrafiltration and thereby the proteins are separated into fractions of different molecular size. 2. The method according to item 1, characterized in that the mechanolytic degradation of the proteins by tuning the process parameters grinding time, grinding media diameter, density of the grinding media, degree and filling ratio and speed of the grinding drum in ball mills or amplitude and frequency of the grinding drum in vibrating mills up to a particle size than 25 microns and molecular weight of the proteins is from 10,000 to 50,000. 3. The method according to item 1 and 2, characterized in that the milled products with aqueous media of pH 5 to 9, preferably 6 to 8 in the ratio 1: 3 to 1:30, preferably 1: 5 to 1:15 dispersed and the undissolved components are separated in a known manner. 4. The method according to item 3, characterized in that the undissolved portion is dried in a conventional manner and again subjected to a mechanolytic degradation. 5. The method according to item 1, characterized in that membranes are used for ultrafiltration with a molecular retention capacity of 10,000 to 50,000, preferably from 10,000 to 30,000. 6. The method according to item 1 and 5, characterized in that the protein-containing solutions are subjected to diafiltration. 7. The method according to item 1, 5 and 6, characterized in that the resulting Retenate and filtrates are dried gently by a known method. For this 2 pages drawings Field of application of the invention The invention relates to a process for recovering proteins having improved foaming properties from vegetable and / or animal raw materials containing predominantly globulins, prolamins, glutins or caseins, and from processing products thereof, preferably in the form of protein isolates, protein concentrates and protein-rich flours. The products obtained can be used advantageously as base materials for the production of food foams. Characteristic of the known technical solutions Proteins have different functional properties depending on their composition and structure as well as their recovery, processing and interaction with other ingredients. Among them, the foaming properties are of particular interest for the production of food foams. Simplified described are food foams in the form of accumulated gas bubbles present edible products of whippable and foaming, hydrated vegetable or animal substances, essentially proteins. Physically, it is colloidal (particle sizes 1 nm to 1 μητι) or coarsely dispersed (particle size> 1 μητι) systems in which a gas is the disperse (inner) phase and a liquid, usually water and more rarely a solid, the dispersant (outer phase) , The presence of a solid outer phase is called solid foams or porous bodies. The properties of such colloidal or coarse-disperse systems are determined, apart from specific factors that depend on the components involved, above all, the nature of the phase interface. Interference at the interface z. B. by changing the surface tension, the charge or the viscosity therefore affect the behavior of the systems directly As food or food ingredients foams are used in a variety of forms and compositions. Examples are foamy goods, foam coatings, foam foods, ice cream, egg whites, whipped cream, foam chocolate, beer foam, creams and baked goods. In particular, it should not be discussed here. Both in general and specifically, z. B. in the field of bakery and confectionery technology or confectionery production, reference is made to the considered literature. For the practice of producing food foams, it is as u. a. From the Food Dictionary of TÄUFEL, TUNGER and ZOBEL (1979), it is essential that foam-forming substances must have the ability to reduce the surface tension and to delimit the air or gas bubbles forming during beating by a thin membrane against the liquid. The smaller the gas bubbles are, the more stable the foam behaves. An increase in the stroke time leads to the reduction and homogeneous distribution of the gas bubbles. Depending on the density of the gas bubble storage is free liquid in the foam, which can run off. The liquid can also be held capillary or in the membranes. In practice, gas dispersions are referred to as foams mainly if their gas content is high. The views on the amount of gas are, however, diverging; this information varies from 50 to 90%. The gas bubbles are limited by liquid or solid walls and can occur in the form of nude, film, lamella, membrane or film bubbles. In liquid foams they usually have a lamellar wall structure and spherical shape in fresh foams. However, due to liquid leakage, they quickly change into polyhedra. Due to their large specific surface liquid foams are unstable. The underlying two phases seek to reduce the surface area and thus coalescence; This is accelerated by the flow of liquid from the slats. The instability of a lamellar foam is supported by PUHLMANN (1983): - drainage, - breaking the slats and - gas diffusion.