WO2007076776A1

WO2007076776A1 - Method and device for vacuum drying papaya latex

Info

Publication number: WO2007076776A1
Application number: PCT/DE2006/002197
Authority: WO
Inventors: Norbert Steiner; Cornelia Huhn
Original assignee: Norbert Steiner
Priority date: 2005-12-14
Filing date: 2006-12-11
Publication date: 2007-07-12
Also published as: DE102005060199A1

Abstract

Disclosed are a method and a device for vacuum drying papaya latex to be used for producing papain. The aim of the invention is to be able to produce a high-quality final product, reduce the amount of time and energy required for the production thereof, increase productivity and efficiency, and improve working conditions by designing a method and a device which allow papaya latex to be dried taking into account particularly the instability of enzymes exposed to heat and extended drying times while allowing for a high degree of productivity and reducing emission of harmful substances in the workspace. Said aim is achieved by drying the papaya latex in a double-walled vacuum vessel under the effect of heat generated by a heat source in the double wall at a reduced internal pressure generated by external vacuum pumps, the drying process being shortened by simultaneously swirling the material that is to be dried and thus increasing the surface thereof. In a second embodiment, the drying process takes place in an electrically heated evacuated hot cabinet, the surface being increased by keeping the layer thickness small by means of inserted metal sheets. In both embodiments, the papain that is dried in a powdery form is sucked in a pipe from the hot unit directly into the packaging unit while being packaged in opaque tear-proof foil bags in a bag forming, filling and sealing process.

Description

DESCRIPTION

Method and apparatus for the vacuum drying of papaya latex

Field of application of the invention:

The invention relates to a method and an apparatus for drying papaya latex for use in the recovery of papain in preferably raw papain producer operations. Papain is a proteolytic enzyme from the ^"group of endopeptidases. It consists of 212 amino acids with a known sequence and has a cysteine in the active site (cysteine protease). The catalysis proceeds via an intermediate thioester (therefore classified as thiol protease) and by an adjacent Papain is one of a peptide chain whose cys-25 intermediate forms an acyl enzyme with the participation of His-162 (as acid), Asn-182 and Gin-19.1 Similar to the acylation 1 Deacylation of animal serine proteases after stabilization The tetrahedral intermediate is deacylated with water with the participation of His-162 (as the base) .Papain has a broad functionality, it mainly cleaves peptide bonds involving basic amino acids, but it can also hydrolyze esters and amides Substrate dependent and ranges from pH 4.0 to 7.0. Also, the temperature optimum covers very wide areas, it is between 25 and 4O ⁰ C. The formation of the enzyme papain in the papaya fruit is due to the very thin skin, which is so thin that even shines through the pulp. Thus, unlike other fruit peel, it does not provide adequate protection for the seeds embedded inside. In the course of evolution, an enzymatic protection has developed that lasts as long as the fruit needs to mature. When ripe, the mission of the enzymes is finished, so the papaya is less abundant when it comes to eating mature papayas Green Papaya Papas contain nearly 5,000 percent more papain than mature papayas and papain is made from the latex of immature fruit by drying from Carica papaya L. won. Main field of application is the food industry, where papain is often used in beer production and meat tenderization; it also serves to produce hydrolysates from proteins (eg gelatin). In veterinary medicine, papain is used to deworm cattle. It is used in the leather, paper and adhesives industry as well as in waste disposal. Papain also has significant importance in medical applications. In the digestive system, papain facilitates the digestion of dietary proteins. It may also aid the digestion of gliadin, a component of gluten, in celiac disease patients. This low levels of gluten can be tolerated. In the cardiovascular system, papain contributes to the breakdown of fibrin and fibrinogen, which contribute to the accumulation of blood cells.

Papain also contributes to a well-functioning immune system. There are known antibacterial, anti-inflammatory and antioxidant effects. For example, inflammation and pain can be alleviated by insect bites. Along with other proteases, Papain can help relieve edema, pain and inflammation in sports injuries or arthritis. Papain, along with other proteolytic enzymes, continues to be used to break down harmful immune complexes that can contribute to autoimmune diseases. Like pancreatin, trypsin, lipase and amylase, papain is able to release the tissue-deposited antibodies and immune complexes from the receptors. The "foreign labeling" of the body's own cells is thus abolished and the cells are spared from attack by the body's defense, while papain and trypsin also change the complement protein-relevant regions (CH ² region) of the antibodies and immune complexes and thus prevent activation Since this component, the CH ² domain, is also used in many adhesion molecules, these receptors can also be modified by the enzymes via the same mechanism. It can be assumed that the industrial and medical use of findings from enzyme research will continue to occupy considerably more space in the future, and thus the importance of corresponding enzyme production of plant and animal origin will grow dynamically, especially since enzymes can not currently be produced synthetically.

For this reason, the production of high purity papains should be considered when selecting the manufacturing process.

introduction

The papaya (also Papaifrucht, Baummelone, Pawpaw, Mamao), is a melon-like fruit from the fast-growing, up to 10 m high woody perennial of the melon tree Cärica papaya L. (family Caricäceae) with a scoop of large, handshaped leaves. It comes from tropical America and is grown on plantations in Florida, Hawaii, East and South Africa, Sri Lanka, India, the Malay Archipelago and Australia.

Harvest of papaya (in millions of tons, as of 1994)

Brazil 1.80

China 0.40

Costa Rica 0.02

Ecuador 0.02 India 1.20

Indonesia 0.40

Colombia 0,06

Mexico 0.30

Thailand 0.50 Zaire 0.20

Total 5.70 The egg-shaped elongated to cylindrical fruits are up to 50 cm long in cultivation areas in Guatemala. They have a delicate, thin, yellowish skin and a firm, yellow to red pulp, which encloses the pepper-sized seeds bedded in a milk slime at a thickness of 2.5 to 5 cm.

The fruits are used - for fresh consumption with sugar and lemon juice, - as a papaya brand for drinks, ice cream and jams, - preserved in pieces in syrup or candied.

Of greater importance is the use of the fruits as a source of papain, a proteolytic enzyme (protease).

Mode of Action and Importance of the Enzyme Papain Enzymes are catalysts of biological systems (biocatalysts) that allow the totality of the metabolic processes without altering the equilibrium by lowering the activation energy and increasing the rate.

The enzyme is composed of a protein (apoenzyme) and the active group (prosthetic group). The latter contains the "active center", in part also a protein-bound non-protein moiety (coenzyme), whose specific properties are its catalytic activity (which can accelerate reactions by factors of at least one million) and its specificity, both in the catalyzed reaction and in the reaction The specificity for a substrate is usually high and sometimes even absolute, ie the enzymes can only decompose or degrade certain types of compounds such as proteins, carbohydrates, fats, etc. The catalytic activity of the enzymes It is largely based on the fact that they combine the substrates in a favorable spatial arrangement to form enzyme - substrate (ES) complexes Region of the enzyme bound - the active center. The mode of action of the enzyme corresponds in the figurative sense of the accuracy of key (enzyme) and lock (substrate).

A large, biochemically and food-technologically important group of

Enzymes are the proteins and peptides that cleave proteolytic enzymes - the

Proteases (proteinases). One distinguishes exopeptidases (they split the

Bonds at the end of a peptide chain to form amino acid) and

^The endopeptidases, which cleave specific positions in the backbone of a protein sequence, show that they are the only class of enzymes that can not be classified by substrate specificity, and therefore differentiate according to the type of their mechanism of catalysis. , Aspartate and metalloproteases.

The enzyme papain is a protease, ie a protein-cleaving enzyme from the group of endopeptidases. It consists of 212 amino acids of known sequence and has an active site cysteine (hence a cysteine protease). Catalysis proceeds via an intermediate thioester (hence also classified as a thiol protease) and is facilitated by an adjacent histidine. Papain consists of one of a peptide chain whose cys-25 intermediate forms an acyl enzyme with the participation of His-162 (as acid), Asn-182 and Gin- 19. Similar to the acylation / deacylation of animal serine proteases, after stabilization of the tetrahedral intermediate, it is deacylated with water involving His-162 (as the base). Papain preferably hydrolyzes bonds of peptides containing dicarboxylic or aromatic L-amino acids, such as phenylalanine, in the N-terminal portion of the peptide chain. The pH optimum depends on the substrate and ranges from pH 4.0 - 7.0. The temperature optimum covers very wide ranges, it is between 25 and 40 ⁰ C.

Proteases are produced industrially from microorganisms, from animal organs and from plants. Plant proteases are next to papain nor bromelin (From the juice of fresh pineapple fruits) and Fizin (from the milk juice of immature figs), before which, however, the Papain greater importance. The formation of the enzyme papain in the papaya fruit is due to the very thin shell, which is so thin that even the pulp shines through. Thus, unlike other fruit peel, it does not provide adequate protection for the seeds embedded inside. In the course of evolution, an enzymatic protection has developed that lasts as long as the fruit needs to mature. With maturity is the "mission" of the enzymes. Papain, therefore, can only be obtained from mature but immature fruit.

Papain: occurrence and use

Papain is obtained by drying from the latex of immature fruits of Carica papaya L. It is the most commonly used protease in food production.

Main field of application is the food industry, where papain is often used in beer production and meat tenderization; it also serves to produce hydrolysates from proteins (e.g., gelatin). In veterinary medicine, papain is used to deworm cattle. It is used in the leather, paper and adhesives industry as well as in waste disposal. Furthermore, papain is used in medicine for the treatment of necrotitic tissues and eczema.

Further areas of application in medicine could result from recent research results, according to which papain, as well as pancreatin, trypsin, lipase and amylase, are able to attack the antibodies deposited in the tissue and

Immune complexes release again from the receptors. The

"Foreign labeling" of the body's own cells is thus repealed and the

Cells are spared from an attack by the body's defense. Papain and trypsin also alter those for the complement protein binding-relevant regions (CH ² region) of the antibodies and immune complexes and thus prevent the activation of the complement cascade. Since this building block, the CBP domain, is also used in many adhesion molecules, these receptors can also be altered by the enzymes via the same mechanism.

It can be assumed that the industrial and medical use of findings from enzyme research will continue to occupy considerably more space in the future, and thus the importance of corresponding enzyme production of plant and animal origin will grow dynamically, especially since enzymes can not currently be produced synthetically.

For this reason, the selection of manufacturing processes should take into account the production of high purity papain in order to achieve higher sales prices and to be recommended for further industrial and medical use with a high quality product on the market.

Recovery and Extraction Procedures Papain is obtained by tapping (scratching the skin) of immature but mature papaya fruits, and then collecting and drying the milk juice (latex) that flows out of the cuts. The tapping of fruits should start early in the morning and be finished in the late morning (in the time of highest humidity). At low humidity, the latex flow is reduced.

Two to three vertical cuts, 1-2 mm deep, are made, which meet in the lower part of the fruit. The cuts are made with a clean steel razor blade attached in a rubber shank. The blade should be positioned so that the cuts do not go deeper than 2mm to prevent juice and starch from the fruit from mixing with the latex and deteriorate its quality.

The fruits should be tapped at intervals of 4-7 days; at the first tapping, it is sufficient to make only one cut and place the following two to three cuts next to the first one.

After about 4 - 6 minutes, the flow of latex begins. It is collected in a bowl and then collected in polyethylene containers with a closable lid; The containers should be in the shade. The use of tightly sealable lids and placement in the shade are extremely important to prevent reactions of the latex that result in loss of enzyme activity. Furthermore, contamination by dirt and insects should be avoided. Adhesive latex on the fruits should be carefully scraped off and placed in the collection containers. It is important to ensure that already dried latex is not mixed with fresh, so as not to reduce the quality.

When working with fresh latex, it is essential to avoid any skin contact; Papain is potentially dangerous because prolonged exposure can cause skin damage and, in some cases, allergic reactions. Furthermore, latex must not come into contact with metals such as iron, copper or brass, as it then loses its enzymatic activity. Fresh latex is also not very durable and should be dried as quickly as possible below 5% moisture.

In two or three months, the fruits are ripe and can be harvested. The ripe fruits are edible, but have a low sales value due to their appearance.

US Pat. No. 2,257,218 discloses a method for preparing papain which achieves greater durability of the papain by admixing ordinary salt and the associated water binding. The end product of this process is a gray-white thickened paste.

US Pat. No. 2,650,165 teaches the thickening and pulverization of papaya fruit juice and the mixing with milk powder or the pulverization of a papaya fruit juice milk mixture. The maintenance of certain temperatures during the process should avoid the caramelization of the sugar or the coagulation of the milk.

From Offenlegungsgeschrift DE 1807937 a process is known, which is centrifuged after the extraction or extraction of the latex from the fruits and separated from its natural, chemical and biological impurities. By centrifuging, three phases are formed, whereby at least one liquid phase is treated in such a way as to obtain papain in powder form.

Characteristic of the known technical solutions:

The drying methods are the determining factor for the quality of papain. The following criteria can be assumed:

Papain is a proteolytic enzyme with a heat resistance up to 75 ° C so as not to diminish the quality, the temperature effect during the drying process must be below this maximum.

Fresh latex not very durable and should be dried as quickly as possible below 5% moisture.

When working with fresh latex, it is essential to avoid any skin contact; Papain is potentially dangerous because prolonged exposure can cause skin damage and, in some cases, allergic reactions.

Latex must not come into contact with metals such as iron, copper or Brass, because it then loses its enzyme activity.

Known methods for drying papaya latex are:

a) the sun drying b) the oven drying c) the spray drying

With sun-drying, the lowest product quality is achieved, as the loss of enzyme activity is considerable; In addition, the papain is rapidly turning brown. Nevertheless, in many countries this process is still the most widely used process technology for papain. The latex is simply spread on trays and dried in the sun. For oven drying, paper dryers of simple construction are used. Sri Lanka is generally a simple, one-meter outdoor kiln made of mud or mud bricks. The drying times are different; a guideline is about 4 - 5 hours at 35 - 4O ° C. The drying is over when the latex is friable and not sticky.

The dry product is stored in airtight and light-protected containers (eg sealed clay pots) and kept cool. Spray drying is a process that requires a certain amount of investment in equipment. The product is fed to the drying in liquid form. The water evaporation takes place by atomization of the liquid in the hot air stream. Here, the spray drying makes the principle of surface enlargement own. The temperature of the hot air stream is usually between 150 - 250 ° C and acts only for a period of seconds on the products. Spray-dried papain has a higher enzyme activity and is completely water-soluble. However, the following factors can affect the manufacturing process: 1. High product temperature 2. High atomization pressure with low spray rate

3. High supply air temperature

4. Highest mindfulness when working with this papain form as it can cause allergies by inhalation. Because of this, it is often encapsulated with gelatin.

Object of the invention:

It is an object of the invention to develop methods and apparatus for drying Papayalatex, which are directed to a controlled influence in compliance with the process parameters while reducing the drying time, increasing product quality, reducing the workload and improving working conditions. It is about a gentle drying by a drying process that works with the lowest possible temperatures. However, the drying time should be as short as possible in order to obtain a high quality product, the quality being determined by the enzyme activity. The product should have good instante properties and be characterized by low dust formation. It should be water soluble but have low hygroscopicity.

The essence of the invention:

The invention is based on the object to develop a process and design an apparatus ^■ for papaya latex at temperatures below 75 ⁰ C to dry as quickly as possible and thus to ensure a high product quality. According to the invention, this is done by reducing the air pressure in the drying area. By creating a vacuum, the evaporation temperature of water is reduced and the drying can take place even at temperatures below 100 ⁰ C faster than is possible under normal conditions. In addition, the drying surface is increased by a swirling of the drying mass, thereby further shortening the process time. The product (papayalatex) is drying in supplied viscous form. The evaporation of water takes place under vacuum, which reduces the effective product temperatures during drying to about 40 ° C. The drying takes place in a well-known non-metallic double-walled vessel, wherein the heat sources are installed in the double wall. These can be designed both as electric heating coils, as hot water pipes or as hot air pipes. Vacuum pumps are used to create the vacuum. The swirling of the surface is done by injected air curtains. In a second variant, a well-known heating cabinet is used with electrical heating, in which also by the use of vacuum pumps, the pressure in the drying room is reduced. The enlarged surface is achieved in this variant by spreading on slide-in sheets.

Exemplary Embodiment: The solution according to the invention is to be explained in an exemplary embodiment in two variants. The accompanying drawings show:

Fig. 1. Schematic front view of the double-walled invention

Vacuum drying boilers (vacuum boiler drying) as variant 1

Fig. 2. Schematic front view of the invention

Vacuum drying cabinet (vacuum cabinet drying) as variant 2

Variant 1 The embodiment in variant 1 shows an electrically heated boiler with indirect heating of the boiling vessel. The boiler consists of the boiling vessel (1), which is welded to the outer vessel (2). The intermediate space (3) located between the boiling vessel and the outer vessel forms a vaporous veil around the boiling vessel, whereby the indirect heating of the product located in the boiling vessel takes place. The boiling vessel is closed with a hinged lid (4). Located in the lower part of the Siedegefäßes there is a lock system (10) for discharging the finished product. From here, the papain enters the packaging unit in powder form. The outdoor boiler is surrounded by a heat insulation (8) and a jacket (9). In the lower part of the boiler above the pedestal (11) of the steam generator (12) is arranged, in which the heating elements (13) are integrated. The water from the steam generator is discharged above a balancing valve (14). The control of the pressure in the steam curtain is carried out by an electro-contact pressure gauge (5), a hopper (6) and a safety flap (7) connected to the intermediate space (3). By means of the vacuum pumps (A), a negative pressure is created in the interior of the boiling vessel (vacuum space), whereby the effective product temperatures during drying can be reduced.

Variant 2

The embodiment in variant 2 shows an electrically heated heating cabinet with four superimposed insertion plates (23), whereby the drying takes place on four levels (24) simultaneously with a reduced layer thickness of the starting product. The working temperature is 60 - 70 ⁰ C _3, the temperature is controlled by a temperature regulator (21). The discharge of the final product is done via a lock system (22). Externally, the vacuum pumps (A) are arranged, hu inside of the heating cabinet is thereby created a vacuum space, which allows the reduction of the effective product temperatures during drying.

Claims

A method for vacuum drying papaya latex to obtain pure papain, wherein at reduced air pressure (vacuum) water at

Vaporizes temperatures below the boiling point of 100 ° C and thereby accelerated drying can be achieved at lower temperatures, the papaya latex in viscous form the

Drying process is supplied, the product temperature during drying is about 40 ° C and after the drying process of

Moisture level is less than 5%.

2. The method according to claim 1,

characterized by

an increase in surface area either by propagation of the viscous mass or by a turbulence of the mass in the surface area.

3. Apparatus for the method according to claim 1 or 2,

characterized by

that the drying takes place in a double-walled vacuumized vessel with simultaneous swirling of the drying mass, wherein the reduced air pressure in the boiler is achieved by external vacuum pumps and the heat of drying by heat sources in the

Double wall.

4. Apparatus for the method according to claim 1 or 2,

characterized by

that the drying takes place in an electrically heated, vacuum-heated oven, wherein the papaya latex is spread out on slide-in sheets and the reduced air pressure in the oven is achieved by external vacuum pumps.

Use of pure papain obtained by the process steps of claim 1 for medical or food use.