Alginate enzyme powder capsule prepared by microsized sodium alginate and application thereof

Abstract

The application provides a kind of microsized sodium alginate preparation seaweed enzyme powder capsule and its application, belong to food chemistry technical field.The microsized sodium alginate preparation seaweed enzyme powder capsule provided by the application, after the freeze-drying of freshly prepared microcapsule is added to pure water for 24 hours, its morphology and diameter size are observed using microscope, and are compared with the freshly prepared microcapsule before freeze-drying, and the rehydration % formula is as follows: rehydration %=(L2 / L1+W2 / W1) x 100, wherein, L2 is the length of microcapsule after rehydration, L1 is the length of microcapsule before freeze-drying, W2 is the width of microcapsule after rehydration, and W1 is the width of microcapsule before freeze-drying.The microcapsule provided by the application is prepared using centrifugal force, can successfully cover the unpleasant smell of active substance, determines the deodorization effect according to the rehydration rate of microcapsule, and is verified by evaluation, the method is effective, can formulate evaluation method and basis for raw material production of mass production.

Description

Technical Field

[0001] This invention belongs to the field of food chemistry technology, and in particular relates to a seaweed enzyme powder capsule prepared from micron-sized sodium alginate and its application. Background Technology

[0002] Marine organisms produce a variety of bioactive compounds with potential medicinal, agricultural, and industrial applications. These compounds often possess unique chemical structures and biological activities, such as antibacterial, anticancer, and anti-inflammatory properties, but often have unpleasant tastes and odors. These unpleasant tastes and odors originate from volatile organic compounds produced by marine organism metabolism, such as dimethyl sulfide, trimethylamine, and gesomones. To overcome this challenge, various strategies have been developed to mask or eliminate the unpleasant tastes and odors of these compounds, including chemical methods, central nervous system control methods, and encapsulation methods. Chemical methods use compounds to antagonize specific taste receptors. Central nervous system control methods use a strong taste to reduce the brain's perception of another taste. Encapsulation methods physically encapsulate bitter and fishy compounds, preventing their interaction with taste buds.

[0003] Encapsulation is a research hotspot in modern medicine and food fields. It involves using a stable raw material as a wall material to encapsulate chemically unstable active substances, which are then effectively delivered to the intestines for release. Common encapsulation methods include nanoencapsulation and microencapsulation. Nanoencapsulation uses substances such as proteins and polysaccharides, which interact with the active substance in solution through intermolecular forces, forming a single or multiple protective shell to encapsulate the active substance inside. Examples of common wall materials include casein (Koo, Moket et al. 2016), starch (Oliyaei, Moosavi-Nasab et al. 2020), chitosan (Malgarim Cordenonsi, Faccendini et al. 2019), whey protein (Zhu, Sun et al. 2017), and zein (Li, Xu et al. 2018).

[0004] Microencapsulation typically utilizes sodium alginate microspheres, a widely studied subject (Uyen, Hamid et al. 2020). Sodium alginate can react with divalent cations such as Ca in water. 2+Cross-linking forms a protective film, encapsulating the active substance within the membrane. This not only protects it from stomach acid and allows it to directly enter the intestines, but also completely masks any unpleasant tastes such as bitterness or fishiness associated with the active substance. It has been used to deliver various active substances or drugs, such as guar gum succinate, carboxymethyl starch, and mesalazine, for the treatment of various diseases. However, common methods for preparing sodium alginate currently include spray drying, extrusion, and gelation. Microcapsules prepared using these methods generally have diameters ranging from millimeters to centimeters, and the relatively large particle size significantly limits the application of sodium alginate microcapsules in beverages. Summary of the Invention

[0005] This invention provides a seaweed enzyme powder capsule prepared from micron-sized sodium alginate and its application. The microcapsules are prepared using centrifugal force, which can successfully mask the unpleasant odor of the active substances. The deodorizing effect is determined based on the rehydration rate of the microcapsules and verified through tasting. The method is effective and can provide an evaluation method and basis for the production of raw materials for large-scale production.

[0006] To achieve the above objectives, this invention provides seaweed enzyme powder capsules prepared from micron-sized sodium alginate. After freeze-drying freshly prepared microcapsules using micron-sized sodium alginate, they are added to purified water for 24 hours. Their morphology and diameter are then observed under a microscope and compared with freshly prepared microcapsules before freeze-drying. The rehydration percentage formula is as follows:

[0007] Rehydration % = (L2 / L1 + W2 / W1) × 100

[0008] Where L2 is the length of the microcapsule after rehydration, L1 is the length of the microcapsule before lyophilization, W2 is the width of the microcapsule after rehydration, and W1 is the width of the microcapsule before lyophilization.

[0009] As a preferred option, the evaluation indicators for the fishy smell and taste of seaweed enzyme powder capsules prepared from micron-sized sodium alginate are as follows:

[0010] Rehydration % > 60%, labeled as Grade A, no fishy smell and no grainy texture;

[0011] 50% < rehydration % ≤ 60%, labeled as Grade B, with no fishy smell and slight graininess;

[0012] 40% < rehydration % ≤ 50%, labeled as Grade C, with a slight fishy smell and slight graininess;

[0013] 30% < rehydration % ≤ 40%, labeled as Grade D, with a slight fishy smell and medium graininess;

[0014] Rehydration % ≤30%, labeled as Grade E, with a slight fishy smell and prominent grainy texture.

[0015] Preferably, it is prepared using centrifugal force.

[0016] As a preferred option, the specific steps include:

[0017] Add CaCl2 solution to 10ml-50ml centrifuge tubes to crosslink micron-sized sodium alginate particles;

[0018] Add 1 ml of solution containing micron-sized sodium alginate and seaweed enzyme powder to a 1.5 ml centrifuge tube with a small hole at the bottom. A stainless steel needle of a specified size is inserted into the small hole at the bottom.

[0019] Make a hole with a diameter matching that of a 1.5ml centrifuge tube in the center of the cap of a 10ml-50ml centrifuge tube, and insert the 1.5ml centrifuge tube prepared above into the hole to form a composite cap.

[0020] Centrifuge tubes with composite caps were placed in a centrifuge and centrifuged at room temperature for 8-10 minutes to prepare microcapsules.

[0021] Preferably, the mass fraction of CaCl2 added is 4%-10%.

[0022] Preferably, the added micron-sized sodium alginate has a mass fraction of 4%-10%.

[0023] Preferably, the mass fraction of the added seaweed enzyme powder is 0.1%-2%.

[0024] Preferably, the centrifugation speed is 50-250g, more preferably 150-250g.

[0025] As a preferred option, the stainless steel needles are 19G-24G in size, with an inner diameter of 0.3-0.67mm and a needle length of 1-1.5 inches, or 2.54cm-3.81cm.

[0026] Preferably, microcapsules with no fishy smell, a granular texture, and excellent taste can be prepared when the following conditions are met: rehydration % > 50%, i.e., sodium alginate concentration 4%-10%, CaCl2 concentration 4%-10%, steel needle size 22-24G or more (i.e. inner diameter less than 0.4mm), and centrifugal force set between 150g-250g.

[0027] The present invention also provides the application of seaweed enzyme powder capsules prepared from micron-sized sodium alginate according to any of the above technical solutions in masking the unpleasant odor of hydrophilic active substances.

[0028] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0029] 1. This application uses Design of Experiments (DOE) to analyze the effects of different parameters in the production process, such as sodium alginate concentration, calcium chloride concentration, centrifugal force, and needle diameter, on the rehydration rate of the formed sodium alginate microcapsules. The optimal solution is selected based on response optimizer analysis. Since the rehydration rate is significantly correlated with the fishy smell and taste of the microcapsules, their deodorizing effect can be determined based on the rehydration rate, and verified through tasting evaluation. This provides an evaluation method and basis for the large-scale production of raw materials.

[0030] 2. The method of using centrifugal force to prepare microcapsules to mask the odor of hydrophilic substances (such as seaweed enzyme powder) is the first of its kind in this application, and the microcapsules prepared according to the four indicators verified by the present invention can successfully mask the unpleasant odor of the active substance. Attached Figure Description

[0031] Figure 1 A mold for preparing sodium alginate microcapsules by centrifugal force method according to an embodiment of the present invention;

[0032] Figure 2 The microcapsules provided in the embodiments of the present invention are shown under a microscope before (A), after (B) lyophilization, and after (C) 24 hours after rehydration;

[0033] Figure 3 The relationship between sodium alginate concentration and microcapsule rehydration % provided in the embodiments of the present invention;

[0034] Figure 4 The standard state and other states achieved by the microcapsules provided in the embodiments of the present invention are shown in A - under a 200x microscope, the standard circular shape of the microcapsules; and B - linear sodium alginate cross-linking material.

[0035] Figure 5 The relationship between calcium chloride concentration and microcapsule rehydration % provided in the embodiments of the present invention;

[0036] Figure 6 The relationship between the inner diameter (A) and length (B) of the steel needle and the rehydration % of the microcapsules is provided for embodiments of the present invention.

[0037] Figure 7 The relationship between centrifugal force and microcapsule rehydration % is provided in the embodiments of the present invention;

[0038] Figure 8 The results of the Minitab 15.0 software response optimization analysis provided for the embodiments of the present invention. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Experimental materials

[0041] The seaweed enzyme powder is prepared according to patent CN201510159810.6, and the raw materials such as sodium alginate and calcium chloride are from McLean Company (Shanghai, China).

[0042] Example 1: Preparation of sodium alginate microcapsules by centrifugal force method

[0043] like Figure 1 The apparatus shown involves adding a 1%-10% CaCl2 solution to 10ml-50ml centrifuge tubes to crosslink sodium alginate particles; and adding 1ml of a solution containing sodium alginate (0.5%-10% by mass) and seaweed enzyme powder (0.1%-2% by mass) to a 1.5ml centrifuge tube with a small hole at the bottom. A stainless steel needle of a specified size (19G-24G, with an inner diameter of 0.67 mm) is inserted into the small hole at the bottom. The needles are 0.3 mm in diameter and 1-1.5 inches (2.54 cm-3.81 cm) in length. A hole with a diameter matching that of a 1.5 ml centrifuge tube is made in the center of the cap of a 10 ml-50 ml centrifuge tube. The 1.5 ml centrifuge tube prepared above is inserted into the hole to form a composite cap. Finally, the centrifuge tube with the composite cap is placed in a centrifuge and centrifuged at 50-250 g for 8-10 minutes at room temperature (25°C) to prepare microcapsules.

[0044] The prepared microcapsules were filtered using a 200-mesh filter cloth, and their morphology and diameter were observed under a microscope after collection. They were then freeze-dried using a freeze dryer for later use.

[0045] like Figure 2 As shown, A represents freshly prepared microcapsules, which are round and wrinkle-free, with a diameter ranging from 200 to 500 μm; B represents freeze-dried microcapsules, which are elongated with obvious surface wrinkles and numerous protrusions at both ends; C represents microcapsules that have been freeze-dried, rehydrated in water, and rehydrated for 24 hours. C is elliptical in shape with obvious protrusions at the top and numerous surface wrinkles, and its volume is significantly larger than that of freeze-dried microcapsules but smaller than that of freshly prepared microcapsules.

[0046] Example 2: Study on the Rehydration Performance of Microcapsules by Single Factor Variables

[0047] Using the method described in Example 1, the single-factor preparation of microcapsules was modified (the purpose of the single-factor experiment is to study the influence of a certain factor on the rehydration rate of microcapsules and identify its range in the composite factor study). Then, the freshly prepared microcapsules were freeze-dried and added to pure water for 24 hours. The morphology and diameter of the microcapsules were observed under a microscope and compared with the freshly prepared microcapsules. The rehydration percentage was calculated using the following formula.

[0048] Rehydration%=(L2 / L1+W2 / W1)×100—Formula 1

[0049] Where L2 is the length of the microcapsule after rehydration, L1 is the length of the microcapsule before lyophilization, W2 is the width of the microcapsule after rehydration, and W1 is the width of the microcapsule before lyophilization.

[0050] 2.1 Effect of sodium alginate concentration

[0051] like Figure 3 As shown, the rehydration percentage of the microcapsules increased significantly with increasing sodium alginate concentration. When the sodium alginate concentration was less than 2%, the system could not form standard spherical microcapsules. Figure 4 As shown in A, it forms linear sodium alginate cross-links, such as Figure 4 As shown in B. Therefore, as a single factor, sodium alginate concentration ≥2% is used, and its concentration range for composite factor experiments is 2%-10%.

[0052] 2.2 CaCl2 concentration

[0053] like Figure 5 As shown, the rehydration percentage of the prepared microcapsules gradually increases with increasing calcium chloride concentration. When the calcium chloride concentration is higher than 5%, the calcium chloride concentration as a single factor no longer has a significant effect on the rehydration percentage of the microcapsules. Therefore, the concentration range for conducting composite factor experiments is 1%-10%.

[0054] 2.3 Specifications of Stainless Steel Needles

[0055] like Figure 6 Figure A illustrates the direct effect of using steel needles with different inner diameters on the rehydration percentage of microcapsules. The rehydration percentage of the prepared microcapsules decreases with increasing needle diameter, within the range of 0.3–0.67 mm. When the needle diameter is less than 0.3 mm, needle blockage occurs, meaning no micron-sized particles are formed. When the needle diameter is greater than 0.67 mm, the resulting particles are too large, exceeding the micron range and not falling within the micron-sized particle range studied in this study. Figure 6 Figure B shows that there is no significant effect between the length of the steel needle and the rehydration percentage of the microcapsules. Therefore, the length of the steel needle can be selected based on the length of the centrifuge tube, ensuring that the steel needle does not touch the surface of the CaCl2 liquid. The recommended range is 1-1.5 inches (i.e., 2.54cm-3.81cm).

[0056] 2.4 Centrifugal force

[0057] like Figure 7 As shown, centrifugal force is directly proportional to the rehydration percentage of the microcapsules. As the centrifugal force gradually increases, the rehydration percentage of the microcapsules gradually increases until the centrifugal force exceeds 250g. At this point, the system no longer forms spherical microcapsules, but instead forms linear cross-linked structures, such as... Figure 4 As shown in B. Therefore, when preparing microcapsules, the centrifugal force used during preparation should be less than 250g, that is, the range of 50-250g should be used for the complex factor experiment.

[0058] Example 3: Preparation of capsules with different rehydration rates

[0059] Based on the results of the study on the effects of single-factor variables on rehydration performance, the concentrations of sodium alginate (2%-10%), CaCl2 (1%-10%), steel needle inner diameter (0.3-0.67 mm), and length (unlimited) were established, with centrifugal force set at 50g-250g. Using Minitab 15.0 data analysis software, a combined factorial experiment (DOE) of the above variables was designed (Table 1). In the DOE experimental design, variables were divided into different groups, and an orthogonal design method was used to test the effect of each variable combination with the fewest possible trials. The results of these experiments were analyzed to determine which variables most significantly affected the experimental results and to identify the optimal variable combinations to obtain the best experimental results (Table 2).

[0060] Table 1. Design of DOE orthogonal experiments using four variables: sodium alginate concentration, CaCl2 concentration, needle inner diameter, and centrifugal force.

[0061]

[0062]

[0063] According to the experimental conditions in Table 1, micron-sized particles were prepared, collected, and their morphology and diameter were observed under a microscope. They were then freeze-dried and added to pure water for 24 hours, after which their morphology and diameter were observed under a microscope again. The rehydration rate of the micron-sized particles prepared under different conditions was calculated using Formula 1, and the results are shown in Table 2.

[0064] Table 2 Results of the DOE orthogonal experiment

[0065]

[0066] To find the optimal production parameters for microcapsules, we used response optimizer analysis. The experimental results in Table 2 were processed, and the results are as follows: Figure 8 As shown. Figure 8The effects of four variables on rehydration rate are shown at two levels and at the center point. Black dots represent the experimental results of each design, and red lines represent positive factors affecting the rehydration rate. Through orthogonal experimental design and analysis of the results, the software provides the optimal system: a CaCl2 concentration of 10%, a sodium alginate concentration of 10%, a steel needle inner diameter of 0.3 mm, and a centrifugal force of 250 g can prepare microcapsules with the highest rehydration rate, expected to be 70.5%.

[0067] We used the optimal scheme and prepared microcapsules according to the experimental method in Example 1. We then calculated their rehydration rate, which was 71.1%, basically consistent with the predicted value and the highest among all orthogonal experimental designs. This also verifies the reliability of the orthogonal experiment.

[0068] The rehydration rate under different experimental conditions was analyzed using a response optimizer in Minitab 15.0 software to predict the optimal experimental conditions. Since microcapsules are freeze-dried as a raw material in beverage production, the rehydration percentage is a crucial indicator of product taste. The closer the rehydrated microcapsules are to their original morphology before freeze-drying, the higher their rehydration rate. Such micron-sized particles are not only rounded with fewer surface wrinkles, resulting in a smoother texture and less noticeable graininess when swallowed, but also bind more tightly to the seaweed powder, providing better protection and reducing the likelihood of a fishy taste. Therefore, we selected experimental conditions with a higher rehydration percentage when using the response optimizer analysis.

[0069] Example 4: Evaluation Experiment Verification

[0070] To further verify the effectiveness of the above parameters, we conducted a taste test.

[0071] Tasting panel: 10 fixed members, eating light meals, tasting between 9:00 and 10:00 AM;

[0072] Sample classification: Different microcapsules prepared using the DOE experiment described above were classified according to their rehydration percentage as measured under a microscope:

[0073] A: Rehydration% > 60%, B: 50% < Rehydration% ≤ 60%, C: 40% < Rehydration% ≤ 50%, D: 30% < Rehydration% ≤ 40%, E: Rehydration% ≤ 30%;

[0074] Control group: pure water; untreated seaweed enzyme powder solution of the same concentration.

[0075] All samples were kept at a constant temperature of 15℃.

[0076] Tasting procedure: After shaking thoroughly, take a large gulp of the sample and let it flow in your mouth for more than 10 seconds to experience the fishy taste and mouthfeel of the liquid as it flows in your mouth and when swallowing; samples are tasted in random order, rinse your mouth with water between samples, and let the sample sit for 1 minute between samples.

[0077] Scoring principles for fishy smell: ≤1: no fishy smell; 1 < score ≤2: mild fishy smell; 2 < score ≤4: moderate fishy smell; >4: obvious fishy smell.

[0078] Taste scoring criteria: ≤1: Smooth and without graininess; 1 < score ≤2: Slight graininess; 2 < score ≤4: Medium graininess; >4: Noticeable graininess.

[0079] Overall Score: The scores for fishy smell and taste are combined to obtain the overall score. The average of the scores from ten people is recorded in Table 3. The lower the overall score, the better the evaluation criteria of the system.

[0080] Table 3 Analysis of Sensory Evaluation Methods

[0081]

[0082] According to the experimental results in Table 3, water had the lowest scores for fishy smell and graininess, ensuring the validity of the experiment. The untreated seaweed enzyme powder solution had a prominent fishy smell, therefore masking it was necessary for use as a beverage. We found that the taste gradually worsened as the rehydration percentage of the microcapsules decreased. Specifically, when rehydration percentage > 60%, all tasters could not taste the fishy smell or graininess; when 50% < rehydration percentage ≤ 60%, most tasters could not taste the fishy smell or graininess; when 40% < rehydration percentage ≤ 50%, most tasters could taste a slight graininess and fishy smell; when 30% < rehydration percentage ≤ 40%, most tasters could taste a slight fishy smell and a relatively noticeable graininess; and when rehydration percentage ≤ 30%, all tasters could taste a slight fishy smell and a significant graininess. Therefore, all reviews found microcapsules with a rehydration rate >60% and 50% < rehydration rate ≤60% acceptable. Specifically, when the rehydration rate of the microcapsules is >50% (combining the two levels), the fishy smell and grainy texture of the microcapsules are not detectable, resulting in the optimal taste. When the rehydration rate of the microcapsules is ≤50%, neither the taste nor the ability to mask fishy smells meets the standards.

[0083] Based on the verification of the above evaluation experiments, we classified the prepared microcapsules into 5 categories:

[0084] 1. Rehydration % > 60%, labeled as Grade A, meaning no fishy smell and no grainy texture.

[0085] 2.50% < rehydration % ≤ 60%, labeled as Grade B, meaning no fishy smell and slight graininess.

[0086] 3.40% < rehydration % ≤ 50%, labeled as Grade C, meaning slight fishy smell and slight graininess.

[0087] 4.30% < rehydration % ≤ 40%, labeled as Grade D, meaning slight fishy smell and medium graininess.

[0088] 5. Rehydration % ≤30%, labeled as Grade E, meaning slight fishy smell and prominent grainy texture.

[0089] Among them, grades A and B are judged to be acceptable raw material grades. Based on the experimental results of the single-factor experiment (Example 2), i.e., ensuring rehydration % > 50%, the corresponding industrial production parameters can be derived as follows: sodium alginate concentration 4%-10% (e.g., ...). Figure 3 As shown, when the rehydration percentage is >50%, the corresponding concentration of sodium alginate is 4%-10%, and the concentration of CaCl2 is 4%-10% (e.g., ...). Figure 5 As shown, when the rehydration percentage is >50%, the corresponding CaCl2 concentration is 4%-10%, and the steel needle specification is 22-24G (e.g., Figure 6 As shown in Figure A, when the rehydration percentage is >50%, the inner diameter of the steel needle is less than 0.4mm (i.e., specification 22-24G), the centrifugal force is set between 150g and 250g (e.g., ...). Figure 7 As shown, when the rehydration rate is >50%, the centrifugal force is set between 150g and 250g. When the microcapsule preparation meets the above conditions, the rehydration rate of the freeze-dried raw material is >50%, which can accurately screen out samples with stable performance, no fishy smell, and excellent particle texture, laying a solid foundation for large-scale production.

Claims

1. Seaweed enzyme powder capsules prepared from micron-sized sodium alginate, characterized in that, Microcapsules freshly prepared using micron-sized sodium alginate were freeze-dried and then added to purified water for 24 hours. Their morphology and diameter were observed under a microscope and compared with freshly prepared microcapsules before freeze-drying. The rehydration percentage formula is as follows: Rehydration % = (L2 / L1 + W2 / W1) × 100 Where L2 is the length of the microcapsule after rehydration, L1 is the length of the microcapsule before lyophilization, W2 is the width of the microcapsule after rehydration, and W1 is the width of the microcapsule before lyophilization. The rehydration rate of seaweed enzyme powder capsules prepared from micron-sized sodium alginate is >70%. Seaweed enzyme powder capsules prepared from micron-sized sodium alginate were prepared using centrifugal force; the centrifugal force was set to 250g. The preparation steps for seaweed enzyme powder capsules made from micron-sized sodium alginate include: Add a 10% CaCl2 solution to 10ml-50ml centrifuge tubes to crosslink micron-sized sodium alginate particles; Add 1 ml of a 10% sodium alginate solution containing micron-sized sodium alginate and seaweed enzyme powder to a 1.5 ml centrifuge tube with a small hole at the bottom. A stainless steel needle with an inner diameter of 0.3 mm is inserted into the small hole at the bottom. Make a hole with a diameter matching that of a 1.5ml centrifuge tube in the center of the cap of a 10ml to 50ml centrifuge tube, and insert the 1.5ml centrifuge tube prepared above into the hole to form a composite cap. Centrifuge tubes with composite caps were placed in a centrifuge and centrifuged at room temperature for 8–10 minutes to prepare microcapsules. The evaluation indicators for the fishy smell and taste of seaweed enzyme powder capsules prepared from micron-sized sodium alginate are as follows: Rehydration % > 60%, labeled as Grade A, no fishy smell and no grainy texture; 50% < rehydration % ≤ 60%, labeled as Grade B, with no fishy smell and slight graininess; 40% < rehydration % ≤ 50%, labeled as Grade C, with a slight fishy smell and slight graininess; 30% < rehydration % ≤ 40%, labeled as Grade D, with a slight fishy smell and medium graininess; Rehydration % ≤30%, labeled as Grade E, with a slight fishy smell and prominent grainy texture.

2. The seaweed enzyme powder capsules prepared from micron-sized sodium alginate according to claim 1, characterized in that, The added seaweed enzyme powder has a mass fraction of 0.1% to 2%.

3. The seaweed enzyme powder capsules prepared from micron-sized sodium alginate according to claim 1, characterized in that, The specifications for stainless steel needles are that the needle length is 1 to 1.5 inches, or 2.54 cm to 3.81 cm.

4. The application of seaweed enzyme powder capsules prepared from micron-sized sodium alginate according to any one of claims 1 to 3 in masking the unpleasant odor of hydrophilic active substances.

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