RU2802759C1 - Method for obtaining marine biological calcium from shrimp shell waste - Google Patents

Abstract

FIELD: shrimp processing.

SUBSTANCE: shells and heads of commercial shrimp Pandalus borealis or Pandalus hypsinotus are washed with water. Demineralization is carried out with a mixture of citric and malic acids, the concentration of which is prepared based on their dissociation constants with a molar ratio of acid and calcium of 2:1. The mixture is heated at 80±5°C for 2 hours, then immediately cooled to room temperature. The remaining shells are removed using a strainer, the resulting solution is adjusted to pH 7.0-7.5 with NaOH solution, the precipitate is washed twice with deionized water and dried in an oven to a moisture content of not more than 5% to obtain the finished product.

EFFECT: production of calcium malate-citrate, expanding the base of natural raw materials for obtaining valuable compounds, waste-free shrimp processing technology.

2 cl, 3 tbl, 6 ex

Description

The invention relates to the food, chemical-pharmaceutical, biotechnological industry, to therapeutic and prophylactic practice, namely to methods for producing organic calcium salts from shell-containing raw materials of crustaceans. The calcium-containing composition can be used as a basis for obtaining biologically active food additives (BAA) and functional food products, food or feed additives for vertebrate organisms.

State of the art

The present invention is aimed at obtaining marine biological calcium from shrimp shells - waste from their processing, which is of great importance for the development of coastal areas of the Arctic region. The proposed method will improve the utilization rate of marine resources by creating technologies for the sustainable development of processing aquatic products: (1) the integrated use of resources can improve the marine environment; (2) enrich existing types of marine biological calcium products and optimize the calcium consumption market; (3) enhance the value of waste calcium source in the processing of aquatic products.

Among the elements important for the human body, calcium ranks 5th after the four main elements - carbon, oxygen, hydrogen and nitrogen [Buslaeva, G.N. The importance of calcium for the body and the influence of nutrition on its metabolism // Pediatrics. Supplement to the journal Consilium Medicum. 2009. No.3. P. 4-7].

Calcium is an essential element of the mineral matrix of bones, acts as a regulator of the nervous system, is involved in muscle contraction, blood clotting, secretion and action of hormones, and controls a number of enzymatic processes. Calcium deficiency leads to metabolic disorders, including osteopenia, osteoporosis, and increases the risk of fractures. Calcium deficiency also leads to an acceleration of the development of atherosclerosis [Gromova, O.A., Torshin, I.Yu., Gogoleva, I.V., Grishina, T.R., Kerimkulova, N.V. Organic calcium salts: prospects for use in clinical practice // RMJ. 2012. No. 28. P.1407].

Since it is difficult to ensure optimal dietary calcium intake through regular foods, there is an urgent need to develop compositions aimed at preventing calcium deficiency and normalizing calcium metabolism.

Shrimp shells are waste from the fishing industry for processing crustaceans. In 2010, approximately 6.1 million tons of crustaceans were caught by trawlers in sea waters or caught in inland waters worldwide [Food and Agricultural Organization of the United Nations (FAO) yearbook: Fishery and aquaculture statistics. 2010, Rome: FAO United Nations]. In the period from 2008 to 2013, shrimp catch in Russia amounted to about 9-10 thousand tons per year, and then began to grow steadily. Fishing at the end of 2019 exceeded 42 thousand tons. The main commercial species of shrimp in Russia are northern shrimp (Pandalus borealis Kroyer, 1838) and comb shrimp (Pandalus hypsinotus Brandt, 1851). In the Barents Sea from January to September 2020, 18.7 thousand tons of shrimp were caught [Analytic Research Group (ARG) Russian shrimp market: comprehensive analysis and forecast. March, 2021. https://marketing.rbc.ru/articles/12361/ Release date: March 12, 2021]. Processing shrimp removes the head (cephalothorax) and hard shell, which constitute about 40-66% of its weight, causing environmental problems due to the lack of controlled disposal. Shrimp shells are burned, left to rot on land, dried for poultry feed, or simply thrown back into the sea.

It is known that shell-containing raw materials of crustaceans are characterized by a high content of unique biologically active substances of various classes: proteins, chitin, pigments, calcium. The main mineral components in shrimp shells are calcium and phosphorus, which account for about 44.75 and 7.06% of the total mineral content [Mahmoud, N. S., Ghaly, A. E., & Arab, F. (2007). Unconventional approach for demineralization of deproteinized crustacean shells for chitin production. Am. J. Biochem. Biotechnol, 3(1), 1-9.]. The chemical composition of the shells of northern deep-sea shrimp is not subject to seasonal fluctuations and is a stable raw material for recycling.

Thus, shrimp shells are an underappreciated natural source of calcium, which may be a suitable raw material for calcium production. Calcium in shrimp shells is naturally present as calcium carbonate, closely bound to the mineralized protein matrix of the chitin complex, and is usually removed from shrimp shell waste during chitin production.

Preparations directly containing calcium are divided into organic and inorganic. Data from pharmacology, experimental and clinical medicine indicate the promise of using organic calcium salts such as lactate, gluconate and citrate [Gromova, O.A. and others. Organic calcium salts: prospects for use in clinical practice//Breast Cancer. 2012. No. 28. P.1407]. Organic acid calcium, such as calcium citrate, calcium L-lactate, calcium gluconate, calcium acetate, calcium formate and calcium propionate, have higher bioavailability, solubility and absorption rate regardless of gastric contents, since they are less sensitive to gastric pH than carbonate calcium. Among organic calcium salts, gluconate and lactate are less concentrated forms of calcium, making them ineffective oral supplements. Calcium acetate and calcium propionate are also not widely used. Calcium combined with two or more organic acids, such as calcium malate citrate, has increased activity compared to using monoorganic calcium acid alone [Jarosz, M., & Rychlik, E. (2019). Calcium and vitamin D intake and colorectal cancer morbidity rates in Poland. Annals of Oncology, 30, iv50.].

There is a known method for preparing composite calcium powder from marine sources of amino acids, such as shrimp shells, crab shells, fish bones, etc., which includes the following stages: washing the remaining aquatic products; grinding; desalting in water in a ratio of 1:5 when heated to 80°C for 40 minutes and treated with ultrasound; preliminary acid hydrolysis with the addition of guar gum; microbial fermentation with the addition of Bacillus licheniformis, Bifidobacterium and Bacillus subtilis for 1-2 days and decomposition; enzymatic hydrolysis using cathepsin and papain; adding amino acid solution; drying; ultrafine grinding [CN 108208847 (A), Preparation method of marine source amino acid compound calcium powder, A23L 33/16; A23L 5/00 2018-06-29]. In this case, during the preparation process according to the invention, the fermentation unit is increased, and the stages of enzymatic hydrolysis and acid hydrolysis are performed alternately.

There is a known method for producing marine biological composite calcium powder from shrimp shells, crab shells, fish bones, etc., which includes the following stages: (1) washing the remaining aquatic products; (2) grinding; (3) microbial fermentation with Aspergillus oryzae and Lactobacillus for 3-5 days; (4) enzymatic hydrolysis with the addition of cathepsin and papain and acid hydrolysis; (5) adding a mixture of citric, lactic, L-aspartic acids and glycine; 6) drying; 7) grinding. In this case, stages (1)-(3) are repeated several times [CN 107095309 (A), Preparation method of marine biocomposite calcium powder, A23L 17/20; A23L 17/40; A23L 33/16; 2017-08-29]. Prolonged microbial fermentation may cause calcium in shrimp, crab and fish bone shells to be absorbed by microorganisms in large quantities, which is not conducive to further extraction at a later stage. In addition, this process is very lengthy and includes a double chemical transformation of the initial calcium carbonate into a mixture of salts, which also leads to an increase in the stages of washing intermediate products and an increase in wash water to be neutralized.

There is a known method for producing a feed additive for laying hens from shrimp or crab shells, which includes the following steps: washing shrimp and crab shells with water to remove impurities adhering to the surface of shrimp and crab shells, and drying and then grinding the washed shrimp and crab shells in a crusher to obtain powder from shrimp and crab shells; preparing mixed acid from citric acid and malic acid; placing the mixed acid in a container and then adding shrimp and crab shell powder to thermostate the reaction in a water bath; performing centrifugation, extraction and spray drying of the supernatant to obtain a powder containing calcium malate citrate; mixing the resulting powder with lactobacilli powder [CN 109907163 (A), Calcium citrate malate-containing laying hen feed additive prepared through shrimp and crab shell decalcification and method thereof, A23K 10/18; A23K 10/26; A23K 20/105; A23K 20/24; A23K 50/75; 2019-06-21]. The disadvantage of this invention is that it produces a product of low quality, containing impurities, and unsuitable for humans.

There is a known method for obtaining calcium from shrimp shells by sequentially carrying out acid treatment, first drying, grinding, softening, fine grinding and second drying, in addition, harmful substances such as heavy metals adsorbed on the surface of shrimp shells can be removed while how the calcium ingredients in shrimp shells can be preserved to the maximum extent [LU 500088 (B1), The high-affinity shrimp shell calcium powder and its preparation method, A23L 17/40; 2021-10-27]. Food acids are used for hydrolysis, and acetic acid at a concentration of 0.1-0.5 wt.% is preferred. By weight, the ratio of solid and liquid phases of shrimp shell to acid solution is 1:5-10. Acid treatment is carried out under ultrasonic conditions. Ultrasound power 0.4-0.6 W/cm ² , ultrasound time 1-1.5 hours. The first drying method involves drying with hot air at a temperature of 60-80°C to a humidity of 5-7% by weight. Softening is carried out by boiling at high temperature and high pressure. Colloidal grinding is carried out 3-5 times. The second drying uses spray drying. The drying time should be such that the moisture content in the resulting calcium shell powder at an incoming air temperature of 200-240°C to a humidity of 2-7 wt.%.

The disadvantage of this method is the use of acetic acid, the calcium salts of which have low bioavailability, as well as the use of double colloidal grinding, which can lead to aggregation of small particles and a further decrease in bioavailability and manufacturability.

There is a known method for producing calcium citrate by adding to citric acid in the form of a 10% solution of calcium carbonate at a mass ratio of citric acid: calcium carbonate 1.5-1.6:1 at a temperature from 16-18 to 40-45°C, separation sediment and drying at a temperature of 105-110°C to constant weight to obtain the finished product in the form of anhydrous tri-calcium citrate [RU 2703719 (C1), C07C 51/41. Method for producing calcium citrate, publ. 2019-10-22].

There is a known method for producing calcium hydrogen orthophosphate from the shells of the flat sea urchin Scaphechinus mirabilis and the commercial sea urchin Strongylocentrotus nudus [Patent RU 2611847 (C1). Method of producing a calcium-containing composition from the shell of sea urchins, A61K 35/616; 2017-03-01] This method involves demineralization of raw materials with a stoichiometric amount of concentrated phosphoric acid, followed by the addition of distilled water at an acid-water ratio of 1: (0.1-0.05). After complete decomposition of calcium carbonate, calcium hydrogen orthophosphate (CaHPO4⋅2H2O) is obtained. The resulting calcium hydrogen orthophosphate is washed three times with 96% ethyl alcohol until completely discolored, the extract is separated by filtration, and the target product is dried at a temperature not exceeding 50°C. The disadvantages of this method are: the use of concentrated inorganic acid; low bioavailability of the resulting calcium-containing composition, which mainly contains calcium hydrogen orthophosphate (50.0-55.0%) depending on the method of preparation: in vitro and in vivo studies have found that the absorption of calcium phosphate is lower than calcium lactate and other test salts calcium. The solubility of calcium hydrogen orthophosphate (1.8 g/100 ml) is very low, which in turn inhibits the digestibility of calcium hydrogen orthophosphate [Weerapol Y. et.al. Impact of gastric pH and dietary fiber on calcium availability of various calcium salts//Silpakorn University Science and Technology Journal 2010. V. 4. No. 1. pp. 15-23; Matsumoto S. et al. Comparisons of bioavailability of various calcium salts. Utilization of incisor dentin in parathyroidectomized rats//Aichi Gakuin Daigaku Shigakkai Shi. 1989. T. 27. No. 4.C. 1029-1041].

The closest to the claimed method is a method for obtaining calcium malate citrate from the heads and shells of the Louisiana crayfish Procambarus clarkii. The method includes the stages of preparing shrimp meal: cleaning the heads and shells of P. clarkii, drying the heads and shells for 25-30 hours at a temperature of 45-55°C, grinding and sifting through a sieve with a pore size of 60 mesh to prepare shrimp meal; carrying out acid leaching: preparing a mixed acid from a solution of citric acid with a mass percentage concentration of 20-22% and a solution of malic acid with a mass percentage concentration of 28-32% in a volume ratio of 1: (1.5-2), mixing shrimp flour (g), mixed acid (ml) and distilled water (ml) in a ratio of 1: (3-3.5): (50-55) and leaching; carrying out extraction using an ultrasonic wave and performing vacuum drying to obtain calcium malate citrate powder [CN 103404864 (A), Method for preparing calcium citrate malate from heads and shells of procambarus clarkia, A23L 17/40; A23L 33/00; 2013-11-27]. The disadvantage of the claimed method is the unknown content of calcium malate-citrate in the finished product, which limits its use as a food product for humans.

The objective of the invention is to develop a method for obtaining calcium from shell waste from shrimp processing.

To solve this problem, a method has been developed for obtaining calcium malate citrate from the heads and shells of commercial shrimp Pandalus borealis or Pandalus hypsinotus. The method, like the known ones, includes successive stages: the heads and shells, after preliminary cutting, are washed to remove organic residues; dried; crushed, demineralized with acid solutions; the undissolved precipitate is separated; dried.

The technical problem of the invention is the development of a simple, environmentally friendly and economical technology for the rational use of shrimp processing waste.

The technical result of the invention is the development of a method for producing a calcium-containing composition from the shells and heads of commercial shrimp Pandalus borealis or Pandalus hypsinotus, which are waste from the processing of the aquatic organisms in question, using food organic acids with a high content of the main active ingredient (calcium). The use of shrimp shells and heads to isolate calcium malate citrate allows us to expand the base of natural raw materials for obtaining valuable compounds.

The technical result is achieved by using waste shells and heads of commercial shrimp as raw materials, which are washed with industrial or drinking water to remove mechanical impurities and residues of organic origin. After washing, the raw materials are dried in air at room temperature (20-25°C) for 24 hours. The dried shells and heads are coarsely ground, then ground in an electric mill to less than 80 mesh and mixed with a solution of citric and malic acids. The concentration of acid solutions is prepared based on their dissociation constants to obtain a molar ratio of acid to calcium of 2:1. Calcium extraction is carried out by heating the mixture at 80±5°C for 2 hours with periodic stirring. Once complete, the mixture is immediately cooled to room temperature before removing the remaining shells using a strainer. The resulting solution is collected and the pH is adjusted to 7-7.5 using NaOH solution to neutralize excess acid. The precipitate is washed twice with deionized water and dried to a moisture content of no more than 5% in an oven. To obtain a higher calcium content in the final product, calcium malate-citrate is additionally precipitated with ethyl alcohol in a ratio of 1:(2.5-4) (resulting solution: ethyl alcohol) at room temperature (20-25°C) for 24 hours, the precipitate is separated and dried to a constant mass to obtain the finished product.

The advantages of the claimed invention make it possible to consider the isolated calcium malate citrate as a basis for the creation of biologically active food additives, functional nutrition products and the use of the resulting salt in the food industry.

The invention is illustrated by the following examples.

Example 1.

1.0 kg of shells and heads of commercial shrimp Pandalus borealis, after preliminary cutting and washing to remove organic residues, are dried at room temperature (20-25°C) for 24 hours; dried shells and heads are subjected to coarse grinding, then crushed to a powdery state to a size of less than 80 mesh, demineralized with a mixture of 10% citric acid solution and 10% malic acid solution in a volume ratio of 1:3 at a temperature of 80 ° C for 2- x h. After completion of the process, the mixture is immediately cooled to room temperature before removing the remaining shells using a strainer. The resulting solution is filtered from the undissolved precipitate, neutralized with NaOH solution to pH 7-7.5, the precipitate is washed twice with deionized water and dried to a moisture content of no more than 5% in an oven. To obtain a higher calcium content in the final product, calcium malate-citrate is salted out with ethyl alcohol in a ratio of 1:2.5 (the resulting solution: ethyl alcohol) at a temperature of 20-25°C for 24 hours, the precipitate is separated and dried at 105-110°C to constant weight to obtain the finished product. The Ca ²⁺ content in the purified sample of calcium malate-citrate prepared according to example 1 is 24.3%. Example 2.

1.0 kg of shells and heads of commercial shrimp Pandalus hypsinotus, after preliminary cutting and washing to remove organic residues, are dried at room temperature (20-25°C) for 24 hours; dried shells and heads are subjected to coarse grinding, then crushed to a powdery state to a size of less than 80 mesh, demineralized with a mixture of 10% citric acid solution and 10% malic acid solution in a volume ratio of 1:3 at a temperature of 80 ° C for 2 -x hours. Once complete, the mixture is immediately cooled to room temperature before removing the remaining shells using a strainer. The resulting solution is filtered from undissolved precipitate, neutralized with NaOH solution to pH 7-7.5, calcium malate-citrate is salted out with ethyl alcohol in a ratio of 1:4 (resulting solution: ethyl alcohol) at a temperature of 20-25°C for 24 hours , the precipitate is separated and dried at a temperature of 105-110°C to constant weight to obtain the finished product.

The Ca ²⁺ content in the purified sample of calcium malate-citrate prepared according to example 2 is 24.6%.

Example 3. Determination of calcium in samples of marine biological calcium by complexometric titration.

About 0.4 g (exactly weighed) of the substance is dissolved in 25 ml of water when heated, after cooling, add 75 ml of desalted water, add 5-10 drops of a 1% solution of hydroxylamine hydrochloride, 2-3 drops of a 1% solution sodium sulfide, 20 ml of ammonium chloride buffer and 30-50 mg of an indicator mixture of black chromogen with NaCl (the solution turns cherry-red). Titrate the contents with a 0.05 M solution of Trilon B with constant stirring. The cherry-red color of the liquid turns purple near the equivalence point, after which it is titrated slowly. The end of the titration is determined by the appearance of a blue color with a greenish tint (blue-blue).

The Ca ²⁺ content in samples of marine biological calcium prepared according to the claimed method is 21-26%.

Example 4. Preparation of a functional food product in the form of calcium-fortified oat milk.

Oat milk containing 1 g protein, 3.2 g fat, 6.5 g carbohydrates and 0.024 g calcium per 100 ml was heated to 50 ± 1°C before adding potassium citrate (0.67 g/100 ml) to prevent induced calcium coagulates oat protein when heated. The mixture was mixed with sugar (3 g/100 ml), and then the appropriate amount of marine biological calcium in the form of calcium malate-citrate at a concentration of 100 mg Ca/100 ml was dissolved in oat milk to obtain fortified oat milk with a calcium concentration of about 120 mg Ca/ 100 ml, which is similar to cow's milk. The fortified oat milk was pasteurized at 75 ± 1°C for 30 s in a steamer, poured hot into glass bottles, immediately cooled in an ice bath, and stored in a refrigerator. The control mixture was prepared without adding calcium salt.

The organoleptic acceptability of fortified and unfortified oat milk was assessed by 11 untrained experts (3 men and 8 women aged 19-55 years). All samples were prepared the day before testing and stored in the refrigerator (4-8°C). A nine-point hedonic scale was used to rate the acceptability of the overall appearance, color, smell, taste, mouthfeel, and overall acceptability of the samples. The scale ranged from 1 to 9, where 1 was “dislike very much,” 5 was “neither liked nor disliked,” and 9 was “liked very much.”

Example 5. Preparation of a biologically active food supplement in the form of calcium malate-citrate tablets.

The crushed and sifted powder of marine biological calcium in the form of calcium malate-citrate, sorbitol, isomalt, povidone, aspartame is loaded into the mixer, mixed thoroughly for 1÷2 minutes, sifted powders of Aerosil 300 and magnesium stearate and mixed again for 2÷4 minutes . After mixing is completed, the tablet mass is unloaded from the mixer and transferred to the tableting stage. Tablets are obtained by direct compression.

Four tablets (equivalent to 1200 mg of elemental calcium), prepared according to the invention, provide 92% of the requirement of the daily calcium requirement [Norms of physiological needs for energy and nutrients for various groups of the population of the Russian Federation. Methodological recommendations MP 2.3.1.2432-08].

Example 6. Assessment of the effect of calcium malate-citrate on growth in rats when administered orally.

To assess the effect of marine biological calcium in the form of calcium malate-citrate on the growth of rats, an experiment was conducted on 10 outbred male rats. The rats were fed marine biocalcium 3 times a day, mixing the powder into their food. During the observation period, there were no illnesses or deaths in the experimental animals. At the beginning of the experiment, there was no significant difference in the body weight and length of the rats in each group. After 3 weeks of feeding, the body weight of rats in the group taking biocalcium was significantly higher than in the control group. The growth rates of rats in the group taking calcium carbonate were significantly lower than in the groups taking calcium malate-citrate. The effect of calcium malate-citrate on the growth and weight of rats is shown in Table 3.

Claims (2)

1. A method for obtaining marine biological calcium in the form of calcium malate-citrate from shrimp shell waste, which consists in washing the shells and heads of commercial shrimp with water, followed by drying, grinding, demineralization with acid solutions, separating the undissolved sediment, drying, characterized in that that shrimp processing waste is used as raw material, namely the shells and heads of commercial shrimp Pandalus boreal is or Pandalus hypsinotus; demineralization is carried out with a mixture of citric and malic acids, the concentration of which is prepared based on their dissociation constants with a molar ratio of acid and calcium of 2:1; the mixture is heated at 80±5°C for 2 hours, then immediately cooled to room temperature, the remaining shells are removed using a mesh filter, the resulting solution is adjusted to pH 7.0-7.5 using NaOH solution, the precipitate is washed twice deionized water and dried to a moisture content of no more than 5% in an oven to obtain the finished product. 2. The method according to claim 1, characterized in that the precipitate of calcium malate citrate is additionally precipitated with ethyl alcohol in a ratio of 1:2.5-4; the resulting solution: ethyl alcohol at a temperature of 20-25°C for 24 hours, the precipitate is separated and dried at a temperature of 105-110°C to constant weight to obtain the finished purified product.