Protein hydrolysates are used in the medical and food industries, as well as in microbiology. Their production is based on the breakdown of organic compounds. The resulting composition is easier to digest by the human and animal body, has a high nutritional value. These compounds are especially important in the manufacture of hypoallergenic infant formula.
Description
Protein hydrolysates are substances obtained as a result of the decomposition of protein by reaction with water. Cleavage occurs in the presence of catalysts: acids, alkalis or enzymes. As a result, the peptide bonds of the high-molecular chain are destroyed, and the final product is a complex mixture consisting of individual amino acids, their sodium s alts, and polypeptide residues. This process, using the example of a tripeptide, is shown in the picture below.
Hydrolysates of different types of proteins, obtained at the same depth of their cleavage, have an identical composition. These substances are valuable biologically active compounds, since amino acids are the main source of nutrition for tissues andtheir "building material", and peptides are involved in the synthesis of amino acids, play an intermediary role in metabolic processes and serve as immunomodulators.
The main components of protein hydrolysates are shown in the illustration below.
The final product contains the largest amount of amino acids such as:
- glutamine;
- aspartic;
- pyrrolidine-α-carboxylic (proline);
- 2-amino-5-guanidinepentanoic (arginine);
- 2-aminopropane (alanine);
- 2-amino-4-methylpentanoic (leucine).
Properties and features
Protein hydrolysates have the following biological characteristics:
- high physiology;
- good digestibility with various routes of administration;
- no toxicity, antigenicity, allergic reactions;
- non-hormonal nature of compounds.
The main physical and chemical criteria for the use of these substances are:
- viscosity;
- the ability to dissolve in water;
- emulsification;
- gel and foaming.
These parameters depend on the type of feedstock, the method of splitting, the reagents used, the conditions of the technological process. The following features are typical for certain types of hydrolysates:
- soy hydrolysis products are poorly soluble at pH=4-5.5;
- whey, casein, meathydrolysates exhibit good thermal stability in the presence of divalent metal s alts when heated to 130 °C;
- compounds derived from fish waste are highly soluble even at low degradation rates;
- deep hydrolysis used to produce hypoallergenic formulations results in an almost complete loss of emulsifying properties (except for hydrolysates based on fish protein);
- in the presence of neutral alkali metal s alts, the solubility of protein substances changes (for example, potassium ions lead to its increase);
- viscosity of hydrolysates is much lower compared to the original proteins, and when they are heated, the formation of gel structures does not occur. This favorably affects the creation of food products with a high content of valuable nitrogenous compounds.
Views
Protein hydrolysates are classified according to 2 main criteria. Namely:
- By type of raw materials - fish, soy, dairy, casein, whey, soy, meat, egg. Hydrolysis of protein waste from various industries is one of the most effective ways to recycle it.
- According to the processing method - deep, medium (5-6 days) and low (5-72 hours) degree of cleavage (amino acid content of at least 50, 25 and 15%, respectively).
Cow's milk-based compounds (whole protein, curdled milk or whey) obtained by enzymatic digestion are most often used for the manufacture of clinical nutrition and therapeutic agents. Animal protein hydrolysates are used inmicrobiology, virology, veterinary medicine. Soy products are also hypoallergenic and hypocholesterolemic.
Whey protein hydrolysates have an amino acid composition similar to that of human muscle tissue, and in terms of the number of essential amino acids they surpass all other types of raw materials of animal and vegetable origin.
Receive
There are 3 main ways to produce these compounds:
- Acid hydrolysis using hydrochloric or sulfuric acid as a catalyst. The process occurs when heated to 100-130 ° C and a pressure of 2-3 atmospheres. This method is the most common, as it achieves a deep degree of splitting and eliminates the risk of bacterial contamination. The duration of the reaction is 3-24 hours. The best efficiency is in relation to fibrillar proteins. The disadvantage of this method is that many valuable amino acids and vitamins are destroyed and toxic by-products are formed that require additional purification.
- Alkaline hydrolysis. This method is used less often (mainly in the processing of shellfish and fish), because there is an undesirable conversion of amino acids, lantibiotics (antimicrobial polypeptides of bacterial origin) are formed.
- Enzymatic hydrolysis. Deprived of the shortcomings of the two previous technologies and has high efficiency. The process takes place at a low temperature (25-50 ° C), the acidity of the medium is close to neutral, andatmospheric pressure. This allows you to save the largest number of biologically active components.
The following substances are used as enzymes:
- digestive pancreatin, trypsin, chymotrypsin (especially effective in processing meat and blood);
- plant compounds: ficin, papain, bromelain;
- bacterial enzymes: protosublitin, rapidose;
- substances synthesized using fungal cultures: protoorizans, rimoprotein, proteinin and others.
Complete protein hydrolyzate contains a complete set of amino acids in an optimal ratio, which is especially important for dietary, medical and veterinary purposes. Such a composition can be obtained by deep processing of raw materials, by boiling the solution for many hours in the presence of acid catalysts.
Application
Protein hydrolysates are used in industries such as:
- Medical (manufacturing of medicines, clinical nutrition for the prevention of protein deficiency, therapy for pathologies of the musculoskeletal and connective tissue, metabolic disorders).
- Food (production of processed meats, gelatin, wines, edible films and coatings, canned fish, sauces, bakery products, high-calorie supplements for athletes).
- Microbiological (production of diagnostic culture media).
- Mixed feed production.
Agriculture
As a feed additive, protein hydrolysates from meat,fish, blood and milk are applied in the following cases:
- to increase nonspecific immunity in weakened, sick animals;
- in order to get more weight gain;
- as an adaptogen in stressful situations and in the presence of risk factors (high morbidity and mortality among birds and animals);
- for metabolic disorders and developmental delays.
In addition, fortified feeds can improve the quality of fur in fur-bearing animals.
Milk formulas: protein hydrolysates in baby food
Cow's milk, which is the main raw material for infant formula for artificial breastfeeding, can cause allergic reactions. High-molecular whey proteins, alpha-lactoalbumin, beta-lactoglobulin, and casein, are most active in this respect.
The most effective way to reduce milk allergenicity at present is to obtain milk protein hydrolysates using enzymes and their subsequent ultrafiltration. Such mixtures contain low molecular weight peptides with a molecular weight of less than 1500 D, and their tolerance among children with allergies is at least 90%.
According to the type of protein used to make the dairy product, mixtures are divided into casein, whey (the most common), soy, and mixed. They are also prescribed for malabsorption of nutrients in the intestines and for the prevention of food allergies.
