A method for obtaining a microcapsule and microcapsule obtained by the method

Abstract

The present invention relates to a method (100) for obtaining a microcapsule which has temperature buffering properties so as to play an active role in keeping the temperature of food / pharmaceuticals / cosmetics within the desired limits; combines antioxidant and antimicrobial properties with the ability to be effective in increasing the shelf life as well as quality and safety; and is also biodegradable; and to a microcapsule obtained by the method (100).

Description

[0001] A METHOD FOR OBTAINING A MICROCAPSULE AND MICROCAPSULE OBTAINED BY THE METHOD

[0002] Technical Field

[0003] The present invention relates to a method for obtaining a microcapsule which has temperature buffering properties so as to play an active role in keeping the temperature of food / pharmaceuticals / cosmetics within the desired limits; combines antioxidant and antimicrobial properties with the ability to be effective in increasing the shelf life as well as quality and safety; and is also biodegradable; and to a microcapsule obtained by the method.

[0004] Background of the Invention

[0005] According to the World Health Organization (WHO), every year one in ten people are poisoned by food, many of whom pass away as a result. These data raise serious concerns about the synthetic chemical products that are often used to minimize losses in both processed and fresh foods. The intensive and unconscious use of these products leads to the accumulation of chemical residues in soil, water and air, and ultimately to carcinogenic effects on human health. The increasing prevalence of foodbome diseases has led to an urgent need for more natural and safer food preservatives such as essential oils.

[0006] Essential oils are an effective alternative for food preservation as they inhibit the growth of pathogens and delay food spoilage. However, the use of essential oils in the food field is limited by several factors, such as their high volatility and high probability of spoilage when exposed to heat, humidity, light or oxygen. Therefore, encapsulation of the essential oil is important in order to protect and stabilise these compounds and also to prevent unwanted flavours and odours from being released into the external environment. Thyme essential oil (TEO) is a typical essential oil extracted from plants with a broad spectrum of antimicrobial activities and is approved by the US Food and Drug Administration (FDA). However, TEO is volatile, insoluble in water and thermally unstable, which limits its actual application in food preservation. In addition, essential oils tend to produce strong or unpleasant odours that affect food flavour and the senses of consumers. Therefore, encapsulating or loading essential oils into various carrier matrices, protecting them and enabling their controlled release is a versatile approach to effectively extend the shelf life of food.

[0007] Encapsulation techniques comprising embedding the active component(s) in an external matrix can be used in order to protect the active component(s) from external environment (for example, exposure to chemicals, air, light, etc.) thereof. For example, this enables the active component(s) to be protected when added to a product formulation (for example a food formulation, a pharmaceutical formulation, etc.), thus means that the active component(s) in the product formulation have an acceptable shelf life and / or are not activated prematurely. This also means that the external phase of the product formulation is not adversely affected by the active component(s). The active component(s) are then released when needed (for example upon breaking the capsule or enzymatic degradation of the capsule).

[0008] Several current encapsulation techniques are widely based on the use of synthetic polymers in order to form a protective shell around the active component. However, synthetic polymers may not be suitable as carriers in pharmaceutical and food applications; or their permissible exposure levels may be limited in cosmetic applications. Furthermore, synthetic polymer shell substances may lead to the formation of environmentally harmful microplastics. The use of polymers obtained from natural sources with biodegradable and natural properties has become the target of numerous studies on volatile / essential oil (EO) encapsulation. Among these biopolymers, polysaccharides have great potential for the inclusion of various EOs. A wide range of polysaccharides can be produced as nanofibers (electrospinning) or nanocapsules (electrospraying), offering structural integrity and full biocompatibility. These substances have the ability to interact with various compounds in EOs through functional groups thereof and promote their entrapment.

[0009] Among polymeric biomaterials, alginate is one of the most promising biomaterials due to its convenient sources, being non-toxic and excellent biocompatibility. Alginate is a type of hydrophilic natural polysaccharide extracted from marine brown alga and composed of P-d-mannuronic acid and a-l-guluronic acid. Alginate can rapidly form hydrogels by cross-linking under normal conditions via multivalent stimulants such as Ca2+, Ba2+or Fe3+; the Ca2+is preferred more due to its low toxicity and low cost. Usually it requires two processes, which includes emulsion formation and ion cross -linking, to encapsulate the essential oil in alginate microgels. Conventionally, emulsions are prepared by mechanical mixing or high shear mixing and then converted into alginate microcapsules by means of external, internal or reverse gelling. However, alginate microcapsules obtained from these methods often show diversity in structure and morphology.

[0010] Among the various methods used for essential oil encapsulation, the efficiency of the electrospinning technique over conventional encapsulation techniques has been emphasised in various reports. The reason for this is that no heating is required during its production, which is an important advantage over the preservation of thermally unstable bioactive substances such as essential oils. In addition, electrospinning reaches high values of encapsulation efficiency by ensuring the stability of the compounds during processing and storage. Encapsulation does not provide sufficient effect to prevent essential oils from degradation due to temperature increases. Furthermore, in the presence of materials comprising heat absorption properties in the environment where substances that are easily affected by temperature changes such as food / pharmaceuticals / cosmetics are present, prevention of sudden temperature changes that shorten the shelf life of the products will be possible via thermal buffering. Polyethylene glycols (PEGs) (HO- CH2-(CH2-O-CH2-)n-CH2-OH) are non-ionic surface active agents that have both water solubility and organic solubility properties together. They are biodegradable, non-toxic and non-corrosive, chemically and thermally stable, have a high ignition temperature, and are also inexpensive substances. The melting temperature of PEGs is generally directly proportional to their molar mass. PEGs are suitable for thermal buffering applications due to their high heat capacity; phase changes in between the range of low and medium temperatures; low vapour pressure when melted; chemical and thermal stability; and high ignition temperatures. It is possible to use them in a polymer structure by fixing the form as they have water-soluble properties.

[0011] As a result, no studies have been reported which use sodium alginate for producing fibres or capsules by using biaxial electro spinning / electro spraying methods for encapsulation of essential oils to be used in food / pharmaceuticals / cosmetics or packaging thereof. Furthermore, no studies have been reported which comprise alginate or another biopolymer shell and essential oil (EG) extract prepared through methods other than electro spinning / electro spraying methods; can react to changes in ambient temperature; have thermal buffering properties that can be used in food / pharmaceuticals / cosmetics fields; and also have antioxidant and antimicrobial properties. And this shows that alginate microcapsules having thermal buffering and antioxidant- antimicrobial properties is an area that should be explored by electro spinning / electro spraying technique.

[0012] The Dutch patent document no. NL2026059, an application included in the state of the art, discloses a sodium alginate chitosan microcapsule containing polylysine and nisin and preparation method therefor. The method has steps of mixing Nisin with sodium alginate; dripping a calcium chloride solution to make into a calcium alginate microcapsule; then adding a mixed solution of polylysine and chitosan for secondary coating; and then coating in a sodium alginate solution again; and liquefying a capsule core with a sodium citrate solution, so as to prepare the sodium alginate chitosan microcapsules containing polylysine and Nisin. Compared to free and single polylysine, Nisin and chitosan, the microencapsulated composite antibacterial products containing polylysine, Nisin and chitosan has increased resistance to pH, temperature and enzymes, has increased preservative effect, and may be processed with food without affecting the fermentation process of fermented food.

[0013] Summary of the Invention

[0014] An object of the present invention is to produce a microcapsule which has temperature buffering properties so as to play an active role in keeping the temperature of food / pharmaceuticals / cosmetics within the desired limits; combines antioxidant and antimicrobial properties with the ability to be effective in increasing the shelf life as well as quality and safety; and is also biodegradable by biaxial electro spraying technique.

[0015] Another object of the present invention is to determine and develop suitable conditions for the method of producing microcapsules by electro spraying in a biaxial electrospinning device, which has the capacity of heat absorption-release and thermal cycling between the temperature range of 20-55°C; has antioxidant and antimicrobial functions; is thermally and chemically stable; and has mechanical strength.

[0016] Detailed Description of the Invention “A Method for Obtaining a Microcapsule and Microcapsule Obtained by the Method” realized to fulfd the objectives of the present invention is shown in the figures attached, in which:

[0017] Figure 1 is a flow diagram of the inventive method.

[0018] Figure 2 shows TGA (Thermogravimetric Analysis) curves of the inventive microcapsules.

[0019] Figure 3 shows the 4thand 10thheating and cooling cycles of ALPEG-9 microcapsules in DSC (Differential Scanning Calorimetry).

[0020] Figure 4 shows the 4thand 10thheating and cooling cycles of ALPEG-10 microcapsules in DSC.

[0021] Figure 5 shows the 4thand 10thheating and cooling cycles of ALPEG-11 microcapsules in DSC.

[0022] Figure 6 is the SEM (Scanning Electron Microscope) images of ALCONTROL.

[0023] Figure 7 is the SEM images of ALPEG-7.

[0024] Figure 8 is the SEM images of ALPEG-8.

[0025] Figure 9 is the SEM images of ALPEG-9.

[0026] Figure 10 is the SEM images of ALPEG-10.

[0027] Figure 11 is the SEM images of ALPEG-11.

[0028] The components illustrated in the figures are individually numbered, where the numbers refer to the following: lOO.Method

[0029] The inventive method (100) for obtaining a microcapsule which has temperature buffering properties so as to play an active role in keeping the temperature of food / pharmaceuticals / cosmetics within the desired limits; combines antioxidant and antimicrobial properties with the ability to be effective in increasing the shelf life as well as quality and safety; and is also biodegradable comprises the steps of: preparing a mixture that forms the core of the microcapsules (101); preparing a mixture that forms the shell part of the microcapsules

[0030] (102); preparing a bath mixture number 1 (103); preparing a bath number 2 (104); obtaining microcapsules by putting the core and shell mixtures of microcapsules into bath number 1 (105); coating the outer surfaces of the microcapsules obtained in bath number 1 by putting them into bath number 2 (106).

[0031] In the step of preparing a mixture that forms the core of the microcapsules (101) of the inventive method (100), thyme oil (thyme essential oil, TEO, d=0.917 g / cm3, HLB: 9-9.5) and oleic acid (oleic acid; d=0.89 g / cm3; HLB: 1.0) are mixed at the ratio of 1:2 or 1.1:2.5.

[0032] In the step of preparing a mixture that forms the shell part of the microcapsules (102) of the inventive method (100), firstly, a 2.00% of alginate (AL) solution is prepared by being mixed with a mechanical mixer at 5500-6000 revolutions / minute (rpm) in a water bath at 60-70°C until completely dissolved after a 2.00 g of alginate is slowly added to 100 mL of pure water in a beaker. Then, a 1.75% of alginate solution is prepared by adding pure water to an 87.5 mL of 2.00% of alginate solution to make it up to 100 mL. Polyethylene glycol 1000 (PEG1000) (H(OCH2CH2)nOH; Polyethylene glycol 1000; CAS No: 25322-68-3; MW: 900- 1100 gmol-1) and / or polyethylene glycol 1500 (PEG1500) (HO-CH2-(CH2-O- CH2-)n-CH2-OH; Polyethylene glycol 1500; CAS No: 25322-68-3; MW: 1350- 1650 gmol1) are taken in such a way that the total PEG mass will be 0.875-0.1750 g and the mass ratio of PEG1000:PEG1500 will be 1:0; 0.5:0.5; 0: 1; 0:0 and melted in a water bath at 60-70°C; then a 25-50 mL of 1.75% of alginate solution is added onto it. In the step of preparing a bath mixture number 1 (103) of the inventive method (100), firstly, pure water is added to an 8.323-16.647 g of CaCh to make it up to 250-500 mL in a volumetric flask in order to prepare a 0.3 M CaCh (3.32% w / v- weight per volume) solution. Then, pure water is added to a 2.92-5.84 g NaCl to make it up to 250-500 mL in a volumetric flask in order to prepare a 0.2 M NaCl (1.17 % w / v) solution. Finally, a bath with a pH of 5.8-6.1 is prepared by combining mixtures of a 150-300 mL 0.3 M CaCh (aq.) and a 12.5-25.0 mL NaCl (aq.).

[0033] In the step of preparing a bath number 2 (104) of the inventive method (100), firstly, a 1.0% (0.17 M) acetic acid (aq.) solution is prepared by adding pure water to the 1.0 mL of acetic acid to make it up to 100 mL in a volumetric flask. A 2.00% of chitosan solution is obtained by stirring the mixture in a mechanical mixer at 3200- 3500 rpm until it is completely dissolved after adding 100 mL of a 1.0% acetic acid solution onto 2.0 grams of chitosan. A bath comprising a 30-45 mL of 2.00% of chitosan and a 30-45 mL of 0.3 M CaCh (aq.) and a total mass of 0-10 g of PEG1000 and / or PEG1500 is prepared.

[0034] In the step of obtaining microcapsules by putting the core and shell mixtures of microcapsules into bath number 1 (105) of the inventive method (100), the thyme oil-oleic acid mixture is encapsulated by solidification of alginate due to crosslinking of alginate and Ca+2ions upon dripping microcapsule shell mixture from the outer cylinder and microcapsule core mixture from the inner cylinder of the biaxial apparatus in the form of two nested cylinders into Bath 1 (V= 20 mL) at a rate of 3.8-4.0 mLh1and 0.5-0.7 mLh1, respectively, by applying + 1.04-2.00 kV electric field in the electrospinning device (Yflow brand SEUxxS / D-500 model). The obtained microcapsules are removed from a bath 1 after 15-20 minutes.

[0035] In the step of coating the outer surfaces of the microcapsules obtained in bath number 1 by putting them into bath number 2 (106) of the inventive method (100), a secondary chitosan layer is formed on the alginate shell by holding the microcapsules removed from bath 1 in bath 2 at a volume of 7.5-15.0 mL for 10-15 minutes. The microcapsules are then taken out from Bath 2 and left to dry in a petri plate with a closed lid at room temperature.

[0036] The microcapsules prepared by following the steps of the inventive method (100) are used in the storage and packaging of food / pharmaceuticals / cosmetics, as well as in-home textile and hygienic textile applications. The prepared microcapsules have a good encapsulation rate and small particle size; can absorb heat in the temperature range of 20-55°C by means of PEG1000 and / or PEG1500 included in the shell structure thereof and thus prevent the temperature rise of the packaged food / pharmaceuticals / cosmetics and food / pharmaceuticals / cosmetics degradation due to temperature rise; slow down the degradation of the active components of the essential oil; improve the thermal stability of the essential oil and extend its duration of activity; the alginate shell of the microcapsules reinforced with chitosan effectively reduces the evaporation of the essential oil; stored in a solid form while the essential oil remains unharmed.

[0037] The composition of the shell and core mixtures forming the microcapsules and the applied compositions of Bath 1 and Bath 2 are given in Table 1. The operating conditions of the electrospinning device in the formation of the prepared AL microcapsule samples are given in Table 2.

[0038] Table 1. Compositions of the shell and core mixtures forming the microcapsules and the compositions of Bath 1 and Bath 2 used in capsule formation (AL: Na Alginate; CH: Chitosan) Table 2. Operating conditions applied in the electrospinning device for the production of shell-self microcapsules

[0039] Injector-

[0040] Shell Core to-

[0041] Shell pump Core pump Injector Collector collector relative rate relative rate Voltage Voltage distance At

[0042] Sample viscosity (mLh-1) viscosity (mLh-1) (kV) (kV) (cm) (minute)

[0043] AL- 3.65 4.00 - 0.7 (+) 1.04 (-) 1.04 15.0 15

[0044] CONTROL

[0045] ALPEG-3 3.50 4.00 - 0.7 (+) 1.04 (-) 1.04 15.0 15

[0046] ALPEG-7 3.50 4.00 - 0.7 (+) 1.04 (-) 1.04 15.0 15

[0047] ALPEG-9 4.24 4.00 1.05 0.7 (+) 1.04 (-) 1.04 15.0 15

[0048] ALPEG-10 3.50 4.00 1.05 0.7 (+) 1.04 (-) 1.04 15.0 15

[0049] ALPEG-11 3.65 4.00 1.05 0.7 (+) 1.04 (-) 1.04 15.0 15 Thermogravimetric (TG / DTG-Thermogravimetry / Derivative Thermogravimetry) analysis was realized for the microcapsules obtained by the inventive method (100). Thermal degradation tests of microcapsule samples were determined by using a Seiko Exstar 6200 TG / DTA device. Analyses were realized in a nitrogen atmosphere at a flow rate of 150.0 mLmin1, at a heating rate of 10 °Cmin-1between the range of 25°C and 600°C. Table 3 shows the data of the microcapsules for the temperature at which 10% mass loss occurred (T10); the mass residue at 110°C; the temperature at which 50% mass loss occurred (T50); and the mass residue at 600°C. Figure 2 shows the mass change % curves of microcapsules between the range of 25°C and 600°C in TGA.

[0050] Table 3. TGA data of the microcapsules

[0051] Mass %

[0052] 10% Mass Loss Mass % 50% Mass loss (Residue at 600

[0053] Sample Name Tio(°C) At 110°C Tso (°C) °C)

[0054] AL-CONTROL 72.2 84.5 337.7 39.7

[0055] ALPEG-3 72.3 81.1 395.0 15.8

[0056] ALPEG-7 72.2 76.3 383.8 8.1

[0057] ALPEG-9 72.2 78.7 394.1 5.1

[0058] ALPEG-10 65.1 76.2 388.6 5.3

[0059] ALPEG-11 65.1 83.9 395.3 6.3

[0060] As seen in Figure 2, a three-step thermal degradation was observed in the mass % against temperature graphs of all microcapsule samples. The mass loss of approximately the order of 16-24% observed up to 110°C relates to the removal of the water contained in the microcapsules. Thermal degradation of AE-CONTROE, which has no PEG 1000 / PEG 1500 in its shell structure and does not comprise core, started at a lower temperature compared to other microcapsules. However, despite this, it has the highest residual mass at 600°C. While ALPEG-3,7,9,10 samples showed similar thermal degradation properties, ALPEG-11 sample comprising PEG 1500 in its shell structure showed the highest thermal resistance between the range of approximately 200-400°C. Differential Scanning Calorimetry (DSC) analysis was realized in order to determine the thermal properties of the microcapsules obtained by the inventive method (100). The measurements were realized in a nitrogen atmosphere at a 5 temperature range between -60°C and 60°C, at a heating and cooling rate of 10°C min1for 10 heating-cooling cycles by using a Perkin Elmer DSC 4000 device. Table 4 shows the heating and cooling data of PEG1000, PEG1500, oleic acid, thyme oil and microcapsules at the 10thcycle.

[0061] 10 Table 4. Heating and cooling data of PEG1000, PEG1500, oleic acid, oregano oil, and microcapsules for the 10thDSC cycle

[0062] In Figure 3, the DSC analysis result of ALPEG-9 comprising PEG1000:PEG1500 at the ratio of 1: 1 by mass in the shell structure and in Bath 2 is seen. It is seen that 15 ALPEG-9 started to absorb heat at 33.6°C upon the overlap of the phase change temperature ranges of PEG1000 and PEG1500; the maximum heat absorption temperature thereof was 49.0°C. The heat absorption capacity of ALPEG-9 microcapsules was measured as 75.9 Jg-1at the temperature range between 33.6°C and 49.0°C.

[0063] In Figure 4, the DSC analysis result of ALPEG-10 comprising only PEG1000 in the shell structure and in Bath 2 is seen. It was detected that ALPEG-10 started to absorb heat at 32.9°C and the peak temperature thereof was 41.1 °C. The heat absorption capacity of ALPEG-10 microcapsules was measured as 80.5 Jg1at the temperature range between 32.9°C and 43.4°C.

[0064] In Figure 5, the DSC analysis result of ALPEG-11 comprising only PEG1500 in its shell structure and in Bath 2 is seen. The heat absorption capacity of ALPEG-11 microcapsules was measured as 76.2 Jg-1at the temperature range between 42.5°C and 53.1°C.

[0065] The nanoscale images of the microcapsules obtained by the inventive method (100) were obtained by using a ZEISS EVO LS 10 Scanning Electron Microscope (SEM). The respective images are given in Figure 6, 7, 8, 9, 10 and 11.

[0066] Average particle sizes for microcapsules were determined. The average particle size of the microcapsules was measured by DLS- Dynamic Light Scattering (Nano ZS90 Malvern Instruments). The microcapsules were diluted with pure water at the ratio of 1 / 10 (w / v) in a glass tube and mixed for 60 seconds with the help of a vortex after closing the lid of the tube. The particle-size distribution measurements were realized in the temperature range between 20 °C-45 °C and the measurements were repeated three times. The data shown in Table 5 are given as the average of the three measurements. Average particle sizes vary between the range of 300 - 520 nm at room temperature. Table 5 shows that as the temperature applied to the microcapsules increases, the size of the microcapsules increases. The PDI (Polydispersity Index) data in Table 5 shows that as the temperature applied to the microcapsules increases, the particle mass / size distribution of the nano-sized particles increases and particles with large diameters are formed.

[0067] Table 5. Average particle size (Z-avg) and Poly Dispersity Index (PDI) measurements of microcapsules at different temperatures

[0068] T Z-avg

[0069] Sample Name (°C) (d.nm) PDI

[0070] 20 452.73 0.52

[0071] 25 536.83 0.59

[0072] 30 761.10 0.75

[0073] AL-CONTROL

[0074] 35 1081.33 0.92

[0075] 40 1206.66 0.97

[0076] 45 1463.00 1.00

[0077] 20 334.60 0.66

[0078] 25 370.86 0.65

[0079] 30 600.30 0.67

[0080] ALPEG-3

[0081] 35 1014.36 0.86

[0082] 40 1133.13 0.89

[0083] 45 1314.66 0.92

[0084] 20 330.43 0.58

[0085] 25 407.26 0.68

[0086] 30 548.83 0.60

[0087] ALPEG-7

[0088] 35 887.36 0.83

[0089] 40 1751.33 1.00

[0090] 45 2130.33 1.00

[0091] 20 412.76 0.71

[0092] 25 422.36 0.77

[0093] 30 516.23 0.69

[0094] ALPEG-9

[0095] 35 727.93 0.77

[0096] 40 1026.43 0.85

[0097] 45 1361.66 0.95

[0098] 20 521.06 0.64

[0099] 25 537.16 0.58

[0100] 30 686.26 0.72

[0101] ALPEG-10

[0102] 35 915.23 0.82

[0103] 40 1354.33 1.00

[0104] 45 1453.66 1.00

[0105] 20 458.00 0.59

[0106] 25 514.90 0.65

[0107] 30 637.70 0.59

[0108] ALPEG-11

[0109] 35 978.06 0.83

[0110] 40 1531.00 1.00

[0111] 45 1614.33 1.00 The pH-dependent swelling states of the microcapsules were detected. Buffer solutions with pH 3.0 and pH 7.0 were used for swelling (S) measurements of microcapsules at different pHs. Microcapsules were weighed in tared petri plates (mfirst). A volume of 2.0 mL of buffer solution was added to the microcapsules and kept at room temperature for 30 minutes, 1 hour, 3 hours and 24 hours, then the excess of the solution phase on the sample was removed with filter paper and weighed (miast). Swelling at different pHs was calculated by using Equation 1;

[0112] %S — [(miast—mfirst ) / mfirst]x100% (1)

[0113] Herein shows: S=Swelling in water; mfirst= First dried mass (g); miast= Wet mass (g) (t= 30 minutes, 1 hour, 3 hours and 24 hours). Table 6 shows the percentage of swelling in water at pH 3 and pH 7.

[0114] Table 6. Percentages of swelling of microcapsules in water at different pH values

[0115] The pH-dependent dissolution properties of microcapsules were detected. After the final wet weighing at the end of the swelling experiment, the microcapsules in the petri plate were dried in a drying oven at 40 °C for 2 hours and the final dried substance amount (mdried) was determined by weighing. Solubility in the water phase at different pHs was calculated by Equation 2;

[0116] Solubility =[(mf1rst-mdried) / mfirst]x100% . (2) Table 7 shows the solubility percentages of AL microcapsules at pH 3 and pH 7.

[0117] Table 7. Solubility percentages of microcapsules at different pH values pH=3 pH=7

[0118] Sample Name Solubility %

[0119] AL-CONTROL 86.2 74.9

[0120] ALPEG-3 92.1 96.0

[0121] ALPEG-7 94.3 100.0

[0122] ALPEG-9 90.6 100.0

[0123] ALPEG-10 92.0 100.0

[0124] ALPEG-11 80.5 61.4

[0125] The antioxidant properties of the microcapsules were also determined. The antioxidant activity of the microcapsule samples was evaluated through determination of total phenol amount by using DPPH (2,2-diphenyl-l- picrylhydrazyl) (molar mass: 394.32 g.mol-1) free radical scavenging test and Folin-Ciocalteu Reagent. Firstly, a 0.06 mM of DPPH solution was prepared for DPPH free radical scavenging test by using ethanol solvent. Then, the microcapsules were mixed at the ratio (1: 1) (w / v) with ethanol in a centrifuge tube. The mixtures were kept in the dark for 30 minutes and were shaken occasionally during this period. Then, they were centrifuged in a BIOSAN LMC-3000 centrifuge at 1000 RPM for 2 minutes. A 1.5 mL of supernatant taken from this mixture was mixed with a 1.5 mL of 0.06 mM of DPPH solution and kept at room temperature for 1 minute. Then, its absorbance was measured at a wavelength of 517 nm by using a Pgeneral T80 Double Beam UV-Vis Spectrophotometer. The percentage of DPPH free radical scavenging activity is determined by using Equation 3;

[0126] DPPH scavenging activity %=[(AbsDPPH-AbssamPie) / AbsDPPH]x100 ....(3)

[0127] Herein shows:

[0128] AbsDPPH= Absorbance value of a 0.06 mM of DPPH (ethanol) solution at 517 nm;

[0129] AbssamPie= Absorbance value of sample extracts at 517 nm. Table 8 shows the percentage results of DPPH free radical scavenging activity of AL microcapsules.

[0130] Table 8. The percentage results of DPPH free radical scavenging activity of AL microcapsules

[0131] DPPH Scavenging DPPH Scavenging

[0132] Sample Name AbSDPPH Abssampie Activity (%) Activity (%g ')

[0133] AL-CONTROL 0.6955 0.3438 50.57 4.70

[0134] ALPEG-3 0.6955 0.3435 50.61 5.61

[0135] ALPEG-9 0.6955 0.3415 50.90 5.39

[0136] ALPEG-10 0.6955 0.3590 48.38 5.06

[0137] According to the data in Table 8, ALPEG-10 was the sample that showed the highest percentage of scavenging activity.

[0138] The total phenolic content of the microcapsules was determined by using the Folin- Ciocalteu method with some modifications. Firstly, a 200 mg / L [1.176 mM] of gallic acid was prepared in a volumetric flask by using pure water for the total phenolic content test. Stock solutions were prepared in concentrations of 0.0588, 0.1176, 0.1764, 0.2352, 0.3528, 0.4704 and 0.5880 mM by using pure water. A 0.2 M Folin-Ciocalteu Reagent was prepared by adding pure water to a 10 mL 2 M Folin-Ciocalteu Reagent (Merck, 2 M, d: 1.27 g / mL) to make it up to 100 mL in a volumetric flask

[0139] Microcapsules taken as 30.0±0.1 mg were mixed in a beaker with 10.0 mL of pure water in a 45°C water bath with the help of a magnetic mixer for 1 hour. Then, it was centrifuged with a centrifuge at 3000 rpm for 10 minutes in order to obtain the supernatant. The obtained 1.0 mL of supernatant was added to a 5.0 mL of 0.2 M Folin-Ciocalteu reagent at room temperature. After 7 minutes, the waited samples were mixed by adding a 4 mL of 7.5% of Na2CO3 and kept in the dark at room temperature for 60 minutes. The absorbance of the samples was measured at 765 nm by using a UV- Visible spectrometer. The concentration of total phenolic compounds of the microcapsule samples is expressed as gallic acid equivalents (GAE). Results reflecting phenolic content are expressed as milligrams of gallic acid equivalent per gram microcapsule (mg GAE / g microcapsule). It is given by using the equation obtained from the standard graph (R2 = 0.9818) as follows:

[0140] Abs765= 0.005 mg gallic acid - 0.0073

[0141] Table 9 shows the concentration of total phenolic compounds as gallic acid equivalents (GAE) of AL microcapsules.

[0142] Table 9. Concentration of total phenolic compounds of some microcapsules

[0143] C— C X Vcapsule extract / mcapsuie (mgGAE / g Sample Name ABS760CGAE(mg / L) capsule)

[0144] AL-CONTROL 0.024 33.40 1.13

[0145] ALPEG-3 0.255 525.20 17.89

[0146] ALPEG-9 0.163 341.60 11.21

[0147] ALPEG-10 0.481 977.60 32.39

[0148] According to Table 9, ALPEG-10 was the sample with the highest phenolic content in its structure with 32.39 mg of gallic acid content per gram capsule.

[0149] 3M Petrifilm 6400 Aerobic Count Plate and 3M Petrifilm 6407 Yeast and Mold count plates were used in order to determine the antibacterial properties of the microcapsules. The microcapsules were mixed with peptone water in a glass tube at the ratio of (1: 10) (w / v), crushed with the help of a glass rod and mixed for 1 hour at room temperature by using a mixer. Obtained 1.0 mL of supernatant was dripped onto the center of the count plates and the count plates were kept in a 32°C drying oven. At the end of 48 hours and 72 hours, aerobic bacteria, mold and yeast were counted via the plates. Table 10 shows the results of aerobic bacteria, mold and yeast counts at the end of 48 and 72 hours. While the expression TNTC in the table stands for 'too numerous to count', the results indicated in percentages are the percentages calculated according to the area over which the yeasts have spread. Table 10. Results of antimicrobial test counts of microcapsules AL-CONTROL TNTC TNTC 12% Yeast 12% Yeast + 1 big mold colony

[0150] ALPEG-3 2 2 0 0 (zero mold)

[0151] ALPEG-9 43 43 0 1 small mold

[0152] ALPEG-10 9 9 28 Yeast 31 Yeast + 1 small mold

[0153] According to the obtained data, while ALPEG-10 showed the highest antibacterial properties comprising a mixture of thyme oil and oleic acid extract, ALPEG-9 showed the highest resistance against mold and yeast.

[0154] Within these basic concepts; it is possible to develop various embodiments of the inventive “A Method (100) for Obtaining a Microcapsule and Microcapsule Obtained by the Method (100)”; the invention cannot be limited to examples disclosed herein and it is essentially according to claims.

Claims

CLAIMS1. A method (100) for obtaining a microcapsule which has temperature buffering properties so as to play an active role in keeping the temperature of food / pharmaceuticals / cosmetics within the desired limits; combines antioxidant and antimicrobial properties with the ability to be effective in increasing the shelf life as well as quality and safety; and which is also biodegradable characterized by comprising the steps of; preparing a mixture that forms the core of the microcapsules (101); preparing a mixture that forms the shell part of the microcapsules (102); preparing a bath mixture number 1 (103); preparing a bath number 2 (104); obtaining microcapsules by putting the core and shell mixtures of microcapsules into bath number 1 (105); coating the outer surfaces of the microcapsules obtained in bath number 1 by putting them into bath number 2 (106).

2. A method (100) according to Claim 1; characterized in that in the step of preparing a mixture that forms the core of the microcapsules (101), thyme oil and oleic acid are mixed at the ratio of 1:2 or 1.1: 2.5.

3. A method (100) according to Claim 1; characterized in that in the step of preparing a mixture that forms the shell part of the microcapsules (102), a 2.00% of alginate (AL) solution is prepared by being mixed with a mechanical mixer at 5500- 6000 rpm (round per minute) in a water bath at 60-70°C until completely dissolved after a 2.00 g of alginate is slowly added to 100 mL of pure water in a beaker.

4. A method (100) according to Claim 3; characterized in that in the step of preparing a mixture that forms the shell part of the microcapsules (102), a 1.75% of alginate solution is prepared by adding pure water to an 87.5 mL of 2.00% of alginate solution to make it up to 100 mL.

5. A method (100) according to Claim 3 or 4; characterized in that in the step of preparing a mixture that forms the shell part of the microcapsules (102), polyethylene glycol 1000 and / or polyethylene glycol 1500 are taken in such a way that the total PEG mass will be 0.875-0.1750 g and the mass ratio of PEG1000:PEG1500 will be 1:0; 0.5:0.5; 0: 1; 0:0 and melted in a water bath at 60- 70°C; then a 25-50 mL of 1.75% of alginate solution is added onto it.

6. A system (1) according to Claim 1; characterized in that in the step of preparing a bath mixture number 1 (103), pure water is added to an 8.323-16.647 g of CaCh to make it up to 250-500 mL in a volumetric flask in order to prepare a 0.3 M CaCh solution.

7. A method (100) according to Claim 6; characterized in that in the step of preparing a bath mixture number 1 (103), pure water is added to a 2.92-5.84 g NaCl to make it up to 250-500 mL in a volumetric flask in order to prepare a 0.2 M NaCl solution.

8. A method (100) according to Claim 6 or 7; characterized in that in the step of preparing a bath mixture number 1 (103), a bath with a pH of 5.8-6.1 is prepared by combining mixtures of a 150-300 mL 0.3 M CaCh (aq.) and a 12.5-25.0 mL NaCl (aq.).

9. A method (100) according to Claim 1; characterized in that in the step of preparing a bath number 2 (104), a 1.0% (0.17 M) acetic acid (aq.) solution is prepared by adding pure water to the 1.0 mL of acetic acid to make it up to 100 mL in a volumetric flask.

10. A method (100) according to Claim 9; characterized in that in the step of preparing a bath number 2 (104), a 2.00% of chitosan solution is obtained by stirring the mixture in a mechanical mixer at 3200-3500 rpm until it is completely dissolved after adding 100 mL of a 1.0% acetic acid solution onto 2.0 grams of chitosan.

11. A method (100) according to Claim 9 to 10; characterized in that in the step of preparing a bath number 2 (104), a bath comprising a 30-45 mL of 2.00% of chitosan and a 30-45 mL of 0.3 M CaCh (aq.) and a total mass of 0-10 g of PEG1000 and / or PEG1500 is prepared.

12. A method (100) according to Claim 1; characterized in that in the step of obtaining microcapsules by putting the core and shell mixtures of microcapsules into bath number 1 (105), the thyme oil-oleic acid mixture is encapsulated by solidification of alginate due to cross-linking of alginate and Ca+2ions upon dripping microcapsule shell mixture from the outer cylinder and microcapsule core mixture from the inner cylinder of the biaxial apparatus in the form of two nested cylinders into bath 1 (V= 20 mL) at a rate of 3.8-4.0 mLh1and 0.5-0.7 mLh1, respectively, and by using a voltage of + 1.04-2.00 kV in the electric field in the electrospinning device.

13. A method (100) according to Claim 12; characterized in that in the step of obtaining microcapsules by putting the core and shell mixtures of microcapsules into bath number 1 (105), the obtained microcapsules are removed from a bath 1 after 15-20 minutes.

14. A method (100) according to Claim 1; characterized in that in the step of coating the outer surfaces of the microcapsules obtained in bath number 1 by putting them into bath number 2 (106), a secondary chitosan layer is formed on the alginateshell by holding the microcapsules removed from bath 1 in bath 2 at a volume of 7.5-15.0 mL for 10-15 minutes.

15. A method (100) according to Claim 14; characterized in that in the step of coating the outer surfaces of the microcapsules obtained in bath number 1 by putting them into bath number 2 (106), the microcapsules are taken out from bath and left to dry in a petri plate with a closed lid at room temperature.

16. A microcapsule which is prepared by following the above method (100) steps; are used in the storage and packaging of food / pharmaceuticals / cosmetics and home textile and hygienic textile applications; have a good encapsulation rate and small particle size; can absorb heat in the temperature range of 20-55°C by means of PEG1000 and / or PEG1500 included in the shell structure thereof and thus prevent the temperature rise of the packaged food / pharmaceuticals / cosmetics and food / pharmaceuticals / cosmetics degradation due to temperature rise; slow down the degradation of the active components of the essential oil; improve the thermal stability of the essential oil and extend its duration of activity; effectively reduce the evaporation of the essential oil; stored in a solid form while the essential oil remains unharmed.

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