A starch film-forming composition and a method for preparing soft capsules thereof

Abstract

Provided are a starch film-forming composition and a preparation method of soft capsules thereof. The starch film-forming composition comprises 25-60 wt% of acid-treated starch, 20-40 wt% of a plasticizer and 15-40 wt% of water, wherein the acid-treated starch has a paste viscosity of 5-196 mPa·s, and the paste viscosity is obtained by preparing a 10% w / w starch solution from the acid-treated starch and water, and the acid-treated starch has a phosphate content of 0.01-0.06% (calculated based on phosphorus P). The soft capsules prepared from the starch film-forming composition have a short drying time and uniform moisture, thereby reducing the production cost of the soft capsules.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of soft capsules, in particular to a starch film-forming composition and a preparation method of a soft capsule thereof. BACKGROUND

[0002] At present, most plant-based soft capsules on the market are mainly made of edible gums (carrageenan, gellan gum, pectin, etc.) and modified starch. However, the combination of edible gums and starch or the gel formed by the starch composition has very poor fluidity, which cannot be as good as gelatin gel in terms of fluidity. Therefore, mechanical force or high pressure is needed to promote the flow of the gel, which increases the production cost and poses a greater safety risk.

[0003] CN118141090A discloses a high-stability soft capsule shell and a preparation method thereof. The high-stability soft capsule shell comprises 10-40 parts of gelatin, 1-10 parts of tamarind gum, 5-30 parts of starch, 5-25 parts of plasticizer, 5-10 parts of water-retaining agent, 0.1-2 parts of food additive, and 20-40 parts of water. The water-retaining agent is selected from one or more of xylitol, mannitol, and trehalose. The patent application solves the problem of rapid drying by adding a water-retaining agent.

[0004] CN114306272A discloses a plant soft capsule, a preparation method and use thereof. The plant soft capsule comprises 3-20 parts of carrageenan, 10-50 parts of starch, 10-35 parts of plasticizer, and 30-70 parts of water. The patent application achieves rapid water loss through drum heating.

[0005] There is still a need for more starch film-forming compositions in the art. SUMMARY

[0006] The present application found that acid-treated starch with a phosphate content of 0.01-0.06% (based on phosphorus P) and a gelatinization viscosity of 5-196 mPa·s has strong gelation and high gel strength. When mixed with a plasticizer and water in a certain proportion, it has film-forming properties.

[0007] The present application provides a starch film-forming composition comprising: acid-treated starch, plasticizer and water. A new acid-treated starch is obtained by controlling the paste viscosity of the acid-treated starch to be 5-196 mPa·s and the content of phosphate ester groups to be 0.010-0.060% (calculated as phosphorus P). The starch film-forming composition formed using the new acid-treated starch has the following characteristics: fast water loss efficiency, soft capsules can be prepared, and the prepared soft capsules have short drying time and uniform moisture. In an embodiment, the paste viscosity is the viscosity value of the starch paste viscosity determined by preparing a 10% w / w starch solution of the acid-treated starch and water using a rotational rheometer at the starch paste temperature. In an embodiment, the content of phosphate ester groups is determined according to GB 5009.87-2016 "National Food Safety Standard Determination of Phosphorus in Food".

[0008] In one aspect, the present application provides a starch film-forming composition comprising 25-60 wt% of acid-treated starch, 20-40 wt% of plasticizer and 15-40 wt% of water, wherein the paste viscosity of the acid-treated starch is 5-196 mPa·s and the content of phosphate ester groups is 0.010-0.060% (calculated as phosphorus P).

[0009] In an embodiment, the acid-treated starch is one or more of acid-treated corn starch, acid-treated pea starch, acid-treated potato starch and acid-treated wheat starch.

[0010] In an embodiment, the acid-treated starch is amylose and / or amylopectin.

[0011] In an embodiment, the plasticizer is one or more of glycerol, propylene glycol, polyethylene glycol, sorbitol, erythritol and maltitol.

[0012] In an embodiment, the content of the plasticizer is 22 wt%-38 wt%.

[0013] In an embodiment, the content of the water is 18 wt%-37 wt%.

[0014] In an embodiment, the starch film-forming composition further comprises one or more of a second starch different from the acid-treated starch, a pigment and a flavoring.

[0015] In an embodiment, the second starch is one or more of hydroxypropyl starch, cross-linked starch, acetate starch, oxidized starch and natural starch.

[0016] In an embodiment, the content of the second starch is 2-8 wt%.

[0017] In an embodiment, the content of the pigment and / or flavoring is an acceptable content for soft capsules.

[0018] In one embodiment, the starch film-forming composition comprises an edible gum. Preferably, the edible gum is one or more of gelatin, carrageenan, agar agar, sodium alginate, pectin, xanthan gum and locust bean gum. Preferably, the content of edible gum is 0.1-20 wt%.

[0019] In one embodiment, the starch film-forming composition does not comprise an edible gum. In one embodiment, the starch film-forming composition does not comprise gelatin.

[0020] In one embodiment, the starch film-forming composition does not further comprise a water holding agent.

[0021] In one embodiment, the starch film-forming composition does not comprise one or more of trehalose, mannitol and xylitol.

[0022] In one embodiment, the plasticizer is glycerol and the starch film-forming composition does not further comprise a water holding agent.

[0023] In another aspect, there is provided a soft capsule shell comprising or prepared from the starch film-forming composition described herein. In one embodiment, the water content of the soft capsule shell is 9-15 wt%.

[0024] In yet another aspect, there is provided a method of preparing a soft capsule, comprising the steps of:

[0025] (1) preparing a gel solution from a raw material comprising the starch film-forming composition described herein, and forming the gel solution into a gel shell,

[0026] (2) preparing the gel shell into a shaped soft capsule, and

[0027] (3) drying the shaped soft capsule to a moisture content of 15% or less, to obtain a soft capsule; wherein the drying time of the shaped soft capsule is less than 10 hours, for example 4-10 hours, 5-9 hours, 5-8 hours, 5-7 hours or 5-6 hours.

[0028] In one embodiment, the drying condition is ambient condition or a drying condition with a temperature of 20-25 °C and a humidity of 10-30%. In one embodiment, the drying process is carried out under static condition or without agitation. In one embodiment, the drying method is tray drying.

[0029] In one embodiment, the method comprises

[0030] A) mixing water and a plasticizer to obtain a premix,

[0031] B) mixing the premix with acid treated starch to obtain a gel solution, for example by heating mixing at 90-95 °C for 1-1.5 hours;

[0032] C) Formed soft capsules are prepared from the gel solution and dried to less than 15% moisture.

[0033] In one embodiment, one or more of a second starch, a food gum, a pigment and a flavour are also added in step B). In one embodiment, the method further comprises feeding the gel solution into a gel pot of a soft capsule filling machine, spreading and cooling on a drum to form a gel skin, filling the content during a die cutting and suturing process to form a soft capsule.

[0034] In one embodiment, the gel solution is fed from the gel storage tank through a gel pipe to the gel pot under gravity or under compressed air push of 0.05-0.1 MPa.

[0035] In one embodiment, the formed soft capsules are dried to 9-15% moisture; in one embodiment, the content is a powder or a liquid active ingredient. The content can be an oil, preferably an algal oil.

[0036] In yet another aspect, there is provided a soft capsule comprising a soft capsule shell according to the soft capsule shell described herein or prepared by the method described herein. In one embodiment, the soft capsule comprises a content. Preferably, the content is a powder or a liquid active ingredient. In one embodiment, the content is an oil, preferably an algal oil.

[0037] In yet another aspect, there is provided the use of the soft capsule shell or the soft capsule described herein in food or cosmetics or in the preparation of a medicament.

[0038] The present application has the following technical advantages and benefits:

[0039] (1) The solid matrix in the formula composition of the present application is mainly starch, which can be free of any animal-derived protein, is safe and non-toxic, and can simultaneously meet the consumption needs of different religious belief groups and special dietary groups.

[0040] (2) The starch used in the formula of the present application has a wide source and low price, is biodegradable, can significantly reduce production costs, and produces less "three wastes" in the production process, which is friendly to the environment.

[0041] (3) The process for preparing soft capsules from the starch film-forming composition of the present application is excellent, which can obtain formed soft capsules containing less than 15% moisture with uniform moisture under conventional drying room conditions with short drying time. The preparation method of the present application can reduce the requirements for drying conditions, shorten the drying time, reduce the manual intervention in the drying process, thereby reducing the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A schematic diagram showing the sampling points of each drying tray is shown. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be combined with embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0044] As used herein, "starch film-forming composition" refers to a mixture with starch as the main component, which has good film-forming properties by adding various auxiliary components.

[0045] As used herein, "acid-treated starch" is a kind of modified starch obtained by treating natural starch with inorganic acid under conditions below the gelatinization temperature to change its properties, also known as acid-modified starch. In the process of acid-treated starch, the glycosidic bond in the starch molecule is hydrolyzed under the action of acid, which leads to the breakage of the chain part of the starch molecule and the decrease of the molecular weight. The degree of acidolysis of amylose and amylopectin is different. Amylose is connected by α-1, 4 glycosidic bond, while amylopectin is connected by α-1, 4 glycosidic bond and a small amount of α-1, 6 glycosidic bond. In the acid treatment process, the amorphous region of amylopectin is more easily penetrated by acid and hydrolyzed, while the crystalline region of amylose is relatively difficult to be acidolysed. Therefore, the acidolysis process of starch is divided into two steps: first, the amorphous region of amylopectin is rapidly hydrolyzed, and then the crystalline region of amylose is hydrolyzed, but the latter is slower. The source of acid-treated starch can be corn, pea, potato, wheat. The acid-treated starch can be amylose and / or amylopectin. The gelatinization viscosity of acid-treated starch varies with its raw material (such as corn, potato, wheat starch, etc.), acid treatment degree (degree of hydrolysis) and test conditions (concentration, temperature, instrument), and the gelatinization viscosity of acid-treated starch on the market is 500-3000 mPa·s. As used herein, the gelatinization viscosity refers to the viscosity characteristics exhibited by starch during gelatinization. Starch granules swell by absorbing water under the action of heat and water, and the crystalline structure is destroyed to form a uniform paste system, which is called gelatinization. The gelatinization viscosity refers to the size of the internal friction exhibited by the paste system when it flows or is subjected to shear force, which is usually determined by a viscometer, with the unit of centipoise (cP) or Brookfield viscosity (mPa·s). In this paper, the gelatinization viscosity of acid-treated starch is determined by preparing a 10% w / w solution of acid-treated starch and water, and using a rotational rheometer to measure the viscosity value of the starch paste at the gelatinization temperature. In the present application, the gelatinization viscosity of acid-treated starch can be 5-195 mPa·s.

[0046] As used herein, a plasticizer is a substance that makes a food material more easily processable into a shape and imparts softness, flexibility, or malleability to it by reducing the interaction between macromolecular chains. The plasticizer can include one or any combination of glycerol, propylene glycol, polyethylene glycol, sorbitol, erythritol, and maltitol.

[0047] As used herein, a humectant is a class of additives that can adsorb, lock, and prevent water loss by physical or chemical action, and maintain the texture of the product. The starch film-forming composition described herein includes a plasticizer but does not further include a humectant. Specifically, the humectant is one or any combination of trehalose, mannitol, and xylitol.

[0048] As used herein, ambient conditions refer to the conditions (e.g., pressure, temperature, etc.) of the medium surrounding the soft capsule. The soft capsule described herein can be directly placed in a drying chamber for drying without the need for heating or dehumidification treatment during the preparation process.

[0049] When numerical ranges are referred to herein, any integer or fraction within that numerical range and any range therebetween are encompassed. For example, when "20-40 wt%" is referred to, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, and any fraction therebetween and any range composed of any two of them are encompassed.

[0050] It should be understood that the last significant figure of the numerical values recited herein is rounded; specifically, for example, when the weight percentage is 17.4%, the number "4" after the decimal point in the value under the percentage sign is rounded to 17%, and for example, when the weight percentage is 17.6%, the number "6" after the decimal point in the value under the percentage sign is rounded to 18%. The same understanding applies to the recitation of other parameter values in the DETAILED DESCRIPTION section of the present application, unless otherwise specified.

[0051] Acid-treated starch

[0052] The pasting viscosity of acid treated starch is usually 500-3000 mPa·s. In this context, the acid treated starch can be further acid treated to further reduce the pasting viscosity to 5-196 mPa·s. The method or means for reducing the pasting viscosity is known to those skilled in the art, or the acid treated starch with reduced pasting viscosity can also be customized through commercial channels. It should be understood that although the acid treated starch with pasting viscosity of 5-196 mPa·s used in this application is still called acid treated starch, it is different from the current acid treated starch at least in the physical properties such as pasting viscosity.

[0053] The acid treated starch usually does not contain significant phosphate groups (unless the raw material itself contains phosphorus or process residues), and phosphate groups are usually not intentionally introduced during the production of acid treated starch, because the main purpose of acid treatment (such as HCl or H2SO4 hydrolysis) is to reduce the molecular weight of starch (reduce viscosity), not esterification reaction. However, some starches may naturally contain phosphate groups, or trace amounts of phosphorus may be detected after acid treatment due to process residues (such as phosphate buffer).

[0054] The upper limit of the phosphate content of the acid treated starch is 0.1% (calculated as phosphorus P), and more than this limit is considered to be a phosphate starch. The functionality changes, and the viscosity increases (phosphate enhances the swelling ability). The negative charge of the phosphate group of the acid treated starch enhances the intermolecular repulsion of the starch molecules, destroys the hydrogen bond network between the starch molecules, weakens the structure of the crystalline region, water molecules more easily penetrate into the interior of the granules, accelerate the gelatinization of the starch, the water molecules quickly volatilize during the drying process, the phosphate group inhibits the retrogradation of the starch, avoids the hygroscopicity and moisture return after drying due to the recrystallization of the molecules, and the water stability is higher.

[0055] The present application found that by selecting the phosphate content of the acid treated starch to be 0.010-0.060% (calculated as phosphorus P) and controlling the pasting viscosity to be 5-196 mPa·s, the colloidal or glue solution has excellent flowability, and the flowability is very smooth under gravity conditions. The formed shaped rubber skin of the starch film forming composition can reach the target value of moisture value within 10 hours of drying, and the moisture is uniform. The prepared soft capsules have more uniform moisture, and manual turning is not required during the preparation process, which greatly reduces the production cost.

[0056] Starch film forming composition

[0057] Modified starch has the characteristics of stable physicochemical properties, good gelatinization ability, film forming performance and mechanical properties. By matching a certain proportion of modified starch film forming composition, soft capsules can be prepared. However, the drying time for preparing soft capsules is long, which requires more than 24 hours, and the moisture value can only be controlled below 15%. In addition, manual turning of the soft capsules is required during the drying process to achieve uniform moisture of the soft capsules, so as to avoid phenomena such as soft capsule depression and stickiness caused by uneven moisture. This can reduce the rate of sub-pellets, but increases the labor cost.

[0058] The flowability of the current technology's film-forming composition (either plant gum system or starch gum system) is not as good as gelatin system, and it needs to be forced to flow by mechanical pressure or high pressure air (usually 0.15-0.2 mPa) to form a film and to make soft capsule shell, which increases the difficulty of soft capsule manufacturing.

[0059] In addition, in order to shorten the drying time of soft capsules and to make the moisture uniform, it is necessary to use a high temperature (such as elevated or heated, for example, above 35°C) and low humidity drying environment, combined with a rotating basket dynamic drying. Although the drying time has been shortened from the original 24-36h to 15-20h, it has also brought some negative effects, such as high temperature drying environment can accelerate the aging of the capsule shell and the oxidative degradation of the soft capsule content, and long time dynamic drying rotation of the rotating basket can cause friction scratches on the surface of the soft capsule shell.

[0060] By mixing the new acid-treated starch described herein with plasticizers and water in a certain proportion, a colloid with excellent flowability can be prepared, forming a starch film-forming composition. The soft capsules prepared from the starch film-forming composition have high water loss efficiency, with a moisture value of less than 15% within 10 hours. The moisture of the prepared soft capsules is more uniform, and there is no need for manual turning, greatly reducing the production cost. During the acid hydrolysis process, starch is more likely to undergo chain scission, generating more small molecular fragments. Since its branched structure is easily destroyed by acid hydrolysis, the gelatinization viscosity will be lower, and the gel structure after acid treatment will be looser, with faster water loss.

[0061] The starch film-forming composition herein comprises the new acid-treated starch described herein, a plasticizer, and water. The acid-treated starch can be present in an amount of 25-60 wt%, e.g., 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, 60 wt%, or any range in between, based on the weight of the starch film-forming composition. The plasticizer can be present in an amount of 20-40 wt%, e.g., 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, or any range in between. The water can be present in an amount of 15-40 wt%, e.g., 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, or any range in between. In this context, the acid-treated starch can have a pasting viscosity of 5-196 mPa-s, e.g., 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 196 mPa-s, and any integer or fraction in between or any range of values between any two of them. The pasting viscosity can be determined by methods conventional in the art, e.g., by formulating the acid-treated starch with water to obtain a 10% w / w starch solution, and determining the viscosity value at the starch pasting temperature using a rotational rheometer.

[0062] The starch film-forming composition herein can further comprise one or more of a second starch, a colorant, and a flavoring different from the new acid-treated starch described herein. The second starch can be one or more of a hydroxypropyl starch, a cross-linked starch, an acetate starch, an oxidized starch, and a native starch. The second starch can be present in an amount of 2-8 wt%, for example 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, or any range therebetween. The colorant and / or flavoring can be present in an amount acceptable for soft gelatin capsules and in amounts conventionally employed in the art for the preparation of soft gelatin capsules.

[0063] The starch film-forming composition herein can comprise a food gum, or the starch film-forming composition does not comprise a food gum. The food gum can be one or more of gelatin, carrageenan, agar, sodium alginate, pectin, xanthan gum, and locust bean gum. Preferably, the starch film-forming composition does not comprise a food gum of animal origin, for example gelatin. When the starch film-forming composition comprises a food gum, the food gum can be present in an amount of 0.1-20 wt%, for example 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, or any range therebetween.

[0064] The starch film-forming composition can not further comprise a water holding agent. Preferably, the starch film-forming composition does not comprise one or more of trehalose, mannitol, and xylitol. Preferably, the plasticizer is glycerol and the starch film-forming composition does not further comprise a water holding agent.

[0065] Method of preparing a soft gelatin capsule

[0066] The present application provides a preparation method of starch soft capsule, comprising: A) mixing water and plasticizer to obtain a premix, B) mixing the premix with acid-treated starch at 90-95°C for 1-1.5 hours to obtain the starch film-forming composition. Step B) can further comprise adding one or any combination of hydroxypropyl starch, cross-linked starch, acetic acid ester starch, oxidized starch and natural starch. Step B) can further comprise adding one or any combination of edible glue, including gelatin, carrageenan, agar, sodium alginate, pectin, xanthan gum and locust bean gum. The above method can comprise delivering the glue solution of the starch film-forming composition to the left and right glue boxes of a soft capsule filling machine, spreading and cooling on a rotating drum (e.g. 15-20°C) to form a glue skin, and filling the content during the mold cutting and suturing process to form a soft capsule. The shaped soft capsule can be dried at a temperature of 20-25°C and a humidity of 10-30% for 4-10 hours to a moisture content of 9-15%, thereby obtaining the soft capsule of the present application. When the soft capsule is prepared according to the present application, the drying effect is faster and the moisture content is more uniform.

[0067] The method of preparing soft capsules herein comprises the following steps: (1) preparing a glue solution from the starch film-forming composition described herein, and forming a glue skin from the glue solution, (2) preparing the shaped soft capsules from the glue skin, and (3) drying the shaped soft capsules to a moisture content of 15% or less (e.g. 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%) to obtain soft capsules; wherein the drying time of the shaped soft capsules is less than 10 hours (e.g. 1, 2, 3, 4, 5, 6, 7, 8, or 9 hours), for example 4-10 hours, 5-9 hours, 5-8 hours, 5-7 hours, or 5-6 hours. The drying conditions of the method can be ambient conditions, or drying conditions of a temperature of 15-35°C (e.g. 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35°C) and a humidity of 10-30% (e.g. 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%). The drying step of the method does not require further heating treatment. Preferably, the drying process is carried out under static conditions or without tumbling. Preferably, the process of forming a glue skin from a glue solution is carried out under normal pressure. More particularly, the method comprises A) mixing water and plasticizer to obtain a premix, B) mixing the premix with acid-treated starch to obtain a glue solution, for example by heating the mixture at 90-95°C for 1-1.5 hours; optionally, one or more of a second starch and a food gum are also added in step B); C) preparing shaped soft capsules from the glue solution, and drying the shaped soft capsules to a moisture content of 15% or less. Preferably, the method further comprises delivering the glue solution to a glue box of a soft capsule filling machine, spreading and cooling the glue skin on a drum, and filling the content to form soft capsules during the process of cutting and suturing by a die. Preferably, the shaped soft capsules are dried to a moisture content of 9-15%. Preferably, the content is a powder or liquid active ingredient, for example an oil, preferably an algal oil. Preferably, the glue solution is delivered from a glue storage tank to the glue box through a glue pipe under gravity or under compressed air push of 0.05-0.1 MPa.

[0068] Examples

[0069] To better illustrate and embody the effects of the present application, the following indexes are used to evaluate the sample of the examples and the comparative examples. The materials and instruments used in the examples are commercially available. The determination methods used are conventional determination methods in the art.

[0070] Method

[0071] 1. Drying time determination

[0072] The tray drying method is used, 30 trays are arranged on a trolley, and the soft capsules are dried in a drying room under the drying conditions (temperature 20-25°C, humidity 10-30%). The moisture content of the soft capsules at different drying time points is determined, the target moisture value is 9-15%, and the drying time is evaluated.

[0073] 2. Coefficient of variation evaluation

[0074] The first to the thirtieth trays from bottom to top are taken from different positions, and the moisture values of the soft capsules at different points are detected to evaluate the uniformity and stability thereof.

[0075] The moisture values of the soft capsules at the first tray, four corners and one middle point are detected, respectively;

[0076] The moisture values of the soft capsules at the fifteenth tray, four corners and one middle point are detected.

[0077] The moisture values of the soft capsules at the thirtieth tray, four corners and one middle point are detected.

[0078] The sampling points of each drying tray are shown in Table 1. Figure 1

[0079] Coefficient of variation (CV = standard deviation / mean × 100%)

[0080]

[0081] 3. Moisture values of soft capsule shell determined by halogen moisture meter

[0082] Principle of detection: The core principle of the halogen rapid moisture meter is the thermal gravimetric method, that is, the water in the sample is evaporated by heating, and the water content is calculated according to the mass difference before and after heating of the sample.

[0083] Moisture content (%) = (initial weight - weight after drying) / initial weight × 100%

[0084] The specific operation steps are as follows:

[0085] Preheating: Turn on the power of the halogen rapid moisture meter and preheat it to the set temperature.

[0086] Sampling: Use the sample disc or sample spoon provided with the instrument to take an appropriate amount of sample (usually a few grams).

[0087] Weighing: Put the sample into the instrument, and the instrument automatically records the initial weight.

[0088] Heating and drying: The instrument heats the sample according to the preset heating program to evaporate the water.

[0089] ​Real-time monitoring: The balance built-in instrument real-time monitoring of sample mass changes, and data transmission to the processor.

[0090] Calculate moisture content: When the sample mass reaches a constant weight or reach the preset drying time, the instrument automatically stop heating, and according to the mass loss calculation of the moisture content of the sample.

[0091] Results show: the moisture content of the results directly on the instrument screen, and can choose to print or save data.

[0092] 4. Evaluation of the flow properties of the glue under gravity conditions

[0093] Take 200g glue liquid in 500ML beaker, cup mouth downward 45 degree angle tilt, glue liquid in 1 minute normal flow, flow smoothly. 2 minutes and above can not flow, poor flow or can not flow.

[0094] Smooth flow: represented by ●;

[0095] Can not flow: represented by ○.

[0096] 5. Film forming properties The glue liquid on the rotating drum (15-20 ℃) to extend the cooling of the rubber evaluation:

[0097] Can form rubber: √

[0098] Glue liquid thin, can not form rubber, or glue liquid thick, no flow, can not form rubber: ×

[0099] Because the starch film-forming composition can not be film, can not be made into soft capsules, drying time and moisture value can not be evaluated, represented by “ / ”

[0100] 6. Determination of the paste viscosity and the content of the phosphate groups of the acid treated starch

[0101] The acid-treated starches in the examples were all custom-made and provided by starch suppliers. The starch suspension was prepared by mixing the starch sample with deionized water at a concentration of 10% w / w, and stirred thoroughly to ensure uniform dispersion and avoid clumping. The suspension was left to hydrate for about 30 minutes (room temperature) to allow the starch granules to fully hydrate, and to remove air bubbles (centrifugation or vacuum degassing can be used if necessary). A rotational rheometer (Anton Paar MCR series) was used with a parallel-plate geometry. Temperature control was achieved using a Peltier temperature control system or a circulating water bath to ensure temperature accuracy (±0.1 °C). The measurement mode was dynamic oscillation mode. The gelatinization procedure was temperature programmed: 1. Initial temperature: start at 50 °C for 2 minutes to stabilize the baseline. 2. Heating stage: ramp to 95 °C at a rate of 2-5 °C / min to simulate the gelatinization process. 3. Holding stage: hold at 95 °C for 5-10 minutes to observe the viscosity stability. 4. Cooling stage (optional): cool to 50 °C at a rate of 1-2 °C / min to study the retrogradation behavior. Data collection: continuously record the temperature, G', G", tan delta (= G" / G') or apparent viscosity. Key parameters and gelatinization characteristics: gelatinization onset temperature (Tonset): the temperature at which G' or viscosity starts to rise significantly (can be determined by the tangent method; gelatinization peak temperature (Tpeak): the temperature at which the viscosity or G' reaches its maximum value; gelatinization enthalpy (AH): to be verified by DSC, which cannot be directly measured by rheometer; final viscosity: the viscosity value at the end of the holding stage, reflecting the thermal stability of the starch paste.

[0102] The content of phosphate groups in the acid-treated starches was determined by measuring the phosphorus content according to the national standard GB 5009.87-2016 "Determination of phosphorus in food for food safety national standard".

[0103] 7. Soft capsule preparation

[0104] Water and plasticizer were mixed to obtain a premix, which was heated and mixed with the acid-treated starch at 90-95 °C for 1-1.5 hours to obtain a glue solution. The glue solution was transported from the glue storage tank to the left and right glue boxes of the soft capsule filling machine under gravity, and was spread and cooled on a rotating drum (15-20 °C) to form a glue skin. The filling content, algal oil, was filled into the soft capsules during the mold cutting and suturing process. The shaped soft capsules were dried at a temperature of 20-25 °C and a humidity of 10-30% for 4-10 hours to a moisture content of 9-15%, and the soft capsules were obtained.

[0105] Example 1: Effect of film-forming composition formulation on the determination results

[0106] The formulations of Examples 1-5 and Comparative Examples 1-2 according to Table 1 (in parts by weight) were prepared as described above in the "Preparation of the film-forming composition" section. Soft capsule preparationThe method describes the formation of a gel shell, with algal oil as the core liquid, to prepare algal oil soft capsules. The drying environment is 22°C and 20% humidity. The fluidity, film-forming properties, drying time, moisture content uniformity, and stability of these film-forming compositions were investigated and evaluated.

[0107] Table 1: Formulations and test results of compositions 1-5 (formulations of compositions and control examples are expressed in parts by weight).

[0108] Composition Comparative Example 1 Composition 1 Composition 2 Composition 3 Composition 4 Composition 5 Comparative Example 2 Acid treated potato starch paste viscosity 16 mPa-s Phosphorous content 0.06% 61.50 66.05 107.35 136.88 187.86 271.82 307.00 Glycerol 100.00 100.00 100.00 100.00 100.00 100.00 100.00 Water 85 85 85 85 85 85 85 Flow properties ● ● ● ● ● ● ○ Film forming properties × √ √ √ √ √ × Drying time (hours) / 8 8 6 6 5 / 1st tray sampling point 1 moisture / 14.26% 12.98% 13.55% 13.14% 12.56% / 1st tray sampling point 2 moisture / 14.23% 13.02% 13.51% 13.16% 12.63% / 1st tray sampling point 3 moisture / 14.28% 13.03% 13.60% 13.09% 12.55% / 1st tray sampling point 4 moisture / 14.35% 12.95% 13.58% 13.18% 12.54% / 1st tray sampling point 5 moisture / 14.33% 12.98% 13.51% 13.14% 12.56% / 15th tray sampling point 1 moisture / 14.28% 13.03% 13.51% 13.11% 12.55% / 15th tray sampling point 2 moisture / 14.25% 13.04% 13.53% 13.14% 12.58% / 15th tray sampling point 3 moisture / 14.27% 13.01% 13.57% 13.13% 12.65% / 15th tray sampling point 4 moisture / 14.31% 12.99% 13.56% 13.14% 12.51% / 15th tray sampling point 5 moisture / 14.34% 12.99% 13.54% 13.11% 12.55% / 30th tray sampling point 1 moisture / 14.29% 12.99% 13.58% 13.19% 12.57% / 30th tray sampling point 2 moisture / 14.27% 12.97% 13.56% 13.17% 12.56% / 30th tray sampling point 3 moisture / 14.27% 13.01% 13.56% 13.16% 12.58% / 30th tray sampling point 4 moisture / 14.31% 12.96% 13.58% 13.16% 12.61% / 30th tray sampling point 5 moisture / 14.28% 12.99% 13.57% 13.17% 12.58% / Standard deviation STDEV / 0.03% 0.03% 0.03% 0.03% 0.04% / Average AVERAGE / 14.29% 13.00% 13.55% 13.15% 12.57% / Coefficient of variation CV / 0.24% 0.21% 0.21% 0.21% 0.28% /

[0109] This embodiment used acid-treated potato starch with a phosphorus content of 0.06% and a gelatinized viscosity controlled at 16 mPa·s. Table 1 shows that for the formulation of Comparative Example 1, using less than 25% acid to treat the starch content resulted in a gel with good flowability, but the gel was too thin to form a film, thus preventing the preparation of soft capsules. For the formulation of Comparative Example 2, using more than 60% acid to treat the starch content resulted in a gel with extremely poor flowability, unable to form a film, and also preventing the preparation of soft capsules.

[0110] For formulations of compositions 1-5, the acid-treated starch content is 25%-60%, resulting in a gel with good fluidity that can form a film. During the preparation of algal oil soft capsules, the drying time is 5-8 hours. The moisture values ​​at five sampling points from the 1st, 15th, and 30th trays (from bottom to top) are similar, with a CV < 10%, indicating highly stable data and excellent uniformity.

[0111] Example 2: Effects of acid-treated starches with different gelatinization viscosities and different phosphate ester group contents on the test results

[0112] According to the proportions of composition 3, and based on the formulations of compositions 6-10 and comparative examples 3-6 in Table 2, as described above... Soft capsule Preparation The method describes forming a gel shell, using algal oil as the core liquid, to prepare algal oil soft capsules. The drying environment is 20°C and 25% humidity. In this embodiment, a batch of acid-treated starches with different gelatinization viscosities and different phosphate ester group contents were customized. For acid-treated starches with different gelatinization viscosities and different phosphate ester group contents, the flowability, film-forming properties, drying time, moisture uniformity, and stability of these film-forming compositions were investigated and evaluated.

[0113] Table 2: Effects of acid treatment on starches with different gelatinization viscosities and different phosphate ester groups on the determination results

[0114] Composition Comparative Example 3 Comparative Example 4 Composition 6 Composition 7 Composition 8 Composition 9 Composition 10 Comparative Example 5 Comparative Example 6 Paste viscosity of the acid treated starch mPa-s 4.87 80.34 5.02 65.15 102.51 150.77 195.98 189.73 242.57 Content of the phosphate groups of the acid treated starch (% calculated on phosphorous, dry basis) 0.057 0.008 0.037 0.042 0.05 0.011 0.060 0.07 0.053 Flow properties ● ● ● ● ● ● ● ○ ● Film forming properties × √ √ √ √ √ √ × √ Drying time (hours) / 10 6 6 6 6 6 / 10 1st tray sampling point 1 moisture / 18.54% 13.02% 13.21% 13.56% 13.84% 13.78% / 16.66% 1st tray sampling point 2 moisture / 21.19% 12.99% 13.18% 13.58% 13.79% 13.86% / 22.15% 1st tray sampling point 3 moisture / 26.78% 13.01% 13.19% 13.61% 13.78% 13.79% / 25.34% 1st tray sampling point 4 moisture / 19.50% 13.00% 13.18% 13.58% 13.88% 13.78% / 20.56% 1st tray sampling point 5 moisture / 17.55% 12.97% 13.19% 13.54% 13.74% 13.84% / 16.85% 15th tray sampling point 1 moisture / 16.79% 13.01% 13.22% 13.57% 13.85% 13.91% / 15.78% 15th tray sampling point 2 moisture / 26.78% 13.06% 13.23% 13.58% 13.87% 13.84% / 23.98% 15th tray sampling point 3 moisture / 27.58% 13.04% 13.17% 13.57% 13.83% 13.83% / 25.56% 15th tray sampling point 4 moisture / 19.04% 13.02% 13.19% 13.60% 13.84% 13.77% / 24.15% 15th tray sampling point 5 moisture / 17.89% 12.95% 13.24% 13.64% 13.91% 13.91% / 19.87% 30th tray sampling point 1 moisture / 17.69% 12.98% 13.19% 13.58% 13.79% 13.79% / 16.78% 30th tray sampling point 2 moisture / 27.65% 13.07% 13.20% 13.59% 13.77% 13.86% / 26.15% 30th tray sampling point 3 moisture / 22.88% 13.06% 13.19% 13.62% 13.86% 13.79% / 24.89% 30th tray sampling point 4 moisture / 21.68% 13.03% 13.24% 13.59% 13.82% 13.84% / 22.08% 30th tray sampling point 5 moisture / 16.58% 13.01% 13.18% 13.59% 13.77% 13.77% / 18.11% Standard deviation STDEV / 4.14% 0.03% 0.02% 0.02% 0.05% 0.05% / 3.71% Average AVERAGE / 21.21% 13.01% 13.20% 13.59% 13.82% 13.82% / 21.26% Coefficient of variation CV / 19.51% 0.26% 0.17% 0.18% 0.35% 0.34% / 17.44%

[0115] Table 2 shows that, for the formulation of Comparative Example 3, the prepared adhesive solution has good fluidity; however, if the solution is too thin, it cannot form a film to create a gel, thus making it unsuitable for preparing soft capsules. For the formulation of Comparative Example 4, after drying the algal oil soft capsules for 10 hours, the moisture content failed to meet the standard. Furthermore, the moisture content of the soft capsules fluctuated greatly from bottom to top in the drying tray, and the moisture content at each of the five sampling points on each drying tray showed significant and uneven fluctuations, with a CV exceeding 15%, indicating instability.

[0116] For the formulation of Comparative Example 5, the adhesive solution had high viscosity and poor flowability, making it impossible to form a film and prepare soft capsules. For the formulation of Comparative Example 6, after drying the algal oil soft capsules for 10 hours, the moisture content failed to meet the standard. Furthermore, the moisture content of the soft capsules fluctuated greatly from bottom to top in the drying tray, and the moisture content of the five sampling points in each drying tray also fluctuated greatly and was uneven, with a CV exceeding 15%, indicating instability.

[0117] For formulations 6-10, the gel has good fluidity and can form a film. The drying time for preparing algal oil soft capsules is approximately 6 hours. The moisture values ​​at five sampling points from the 1st, 15th, and 30th trays (from bottom to top) are similar, with a coefficient of variation (CV) < 10%, indicating highly stable data and excellent uniformity. Compositions 7 and 8, which use 0.04-0.05 (as phosphorus phosphorus) phosphate groups and acid treatment of 65.15-102.51 mPa·s on the starch, yielded the best data stability and uniformity.

[0118] Example 3: The effect of other starch or edible gum components in the film-forming composition on the test results.

[0119] According to the formulations of compositions 11-16 in Table 3, as described above... Soft capsule preparation The method describes the formation of a gel shell, with algal oil as the core liquid, to prepare algal oil soft capsules. The drying environment is 25°C and 15% humidity. The fluidity, film-forming properties, drying time, moisture content uniformity, and stability of these film-forming compositions were investigated and evaluated.

[0120] Compositions 11-16 are made from acid-treated potato starch with a gelatinized viscosity of 15.77 mPa·s and a phosphate ester group content of 0.06% (calculated as phosphorus P). Composition 11 contains hydroxypropyl starch. Composition 12 contains native potato starch. Composition 13 contains carrageenan. Composition 14 contains gellan gum. Composition 15 contains pectin.

[0121] Table 3: Effect of other starch or edible gum components in the film-forming composition on the test results

[0122] Composition Composition 11 Composition 12 Composition 13 Composition 14 Composition 15 Composition 16 Paste viscosity of the acid treated starch (15.77 mPa-s) Content of the phosphate groups (0.06% calculated on phosphorous, dry basis) 25.80% 28.00% 32.50% 37.80% 32.60% 35.00% Hydroxypropyl starch 5.50% / / / / / Potato starch / 8.00% / / / / Carrageenan / / 6.50% / / / Gellan gum / / / 3.20% / / Pectin / / / / 10.00% / Gelatin / / / / / 10.00% Glycerol 35.00% 32.00% 30.00% 25.00% 34.00% 30.00% Water 33.70% 32.00% 31.00% 34.00% 23.40% 25.00% Flow properties ● ● ● ● ● ● Film forming properties √ √ √ √ √ √ Drying time (hours) 8 8 6 10 6 8 1st tray sampling point 1 moisture value 14.28% 13.57% 13.24% 13.65% 13.26% 12.78% 1st tray sampling point 2 moisture value 14.27% 13.59% 13.26% 13.61% 13.33% 12.69% 1st tray sampling point 3 moisture value 14.28% 13.60% 13.19% 13.66% 13.29% 12.79% 1st tray sampling point 4 moisture value 14.31% 13.58% 13.28% 13.68% 13.28% 12.76% 1st tray sampling point 5 moisture value 14.32% 13.52% 13.24% 13.61% 13.24% 12.74% 15th tray sampling point 1 moisture value 14.32% 13.56% 13.21% 13.61% 13.25% 12.65% 15th tray sampling point 2 moisture value 14.26% 13.55% 13.24% 13.73% 13.34% 12.75% 15th tray sampling point 3 moisture value 14.27% 13.55% 13.23% 13.67% 13.33% 12.78% 15th tray sampling point 4 moisture value 14.33% 13.56% 13.24% 13.66% 13.34% 12.77% 15th tray sampling point 5 moisture value 14.31% 13.55% 13.21% 13.74% 13.31% 12.81% 30th tray sampling point 1 moisture value 14.29% 13.58% 13.19% 13.68% 13.29% 12.69% 30th tray sampling point 2 moisture value 14.29% 13.55% 13.27% 13.76% 13.27% 12.66% 30th tray sampling point 3 moisture value 14.28% 13.56% 13.26% 13.66% 13.33% 12.69% 30th tray sampling point 4 moisture value 14.31% 13.58% 13.26% 13.68% 13.32% 12.75% 30th tray sampling point 5 moisture value 14.28% 13.60% 13.19% 13.67% 13.27% 12.77% Standard deviation STDEV 0.02% 0.02% 0.03% 0.05% 0.03% 0.05% Average AVERAGE 14.29% 13.57% 13.23% 13.67% 13.30% 12.74% Coefficient of variation CV 0.15% 0.16% 0.23% 0.33% 0.26% 0.39%

[0123] From Table 3, it can be seen that for the formulations of compositions 11-16, the prepared glue solution has good fluidity and can form a film to form a rubber skin. In the preparation of algal oil soft capsules, the drying time is within 6-10 hours. The moisture values of the 5 sampling points of each tray from bottom to top, the 1st tray, the 15th tray, and the 30th tray are close, the CV is less than 10%, the data is highly stable, and the uniformity is very good.

[0124] Example 4: Effect of auxiliary ingredients, pigments or flavors, of the film-forming composition on the determination results.

[0125] According to the formulations of compositions 17-18 in Table 4, the rubber skin was formed as described in the above method, and algal oil soft capsules were prepared with algal oil as the core liquid. The drying environment was 24°C and 12% humidity. The fluidity of the glue solution, film-forming property, drying time, moisture value uniformity, and stability of the film-forming composition were evaluated.

[0126] Compositions 17-18 selected acid-treated starch with a gelatinization viscosity of 15.77 mPa·s, composition 17 contained stevioside and β-carotene natural pigment; composition 18 contained sweet orange oil flavor.

[0127] Table 4: Effect of auxiliary ingredients, pigments or flavors, of the film-forming composition on the determination results.

[0128] Composition Composition 17 Composition 18 Paste viscosity of the acid treated potato starch (15.77 mPa-s) Content of the phosphate groups (0.06% calculated on phosphorous, dry basis) 28.00% 28.00% Glycerol 35.00% 35.00% Water 36.37% 36.54% Steviol glycosides 0.13% / Sweet orange oil flavour / 0.46% Beta-carotene natural colour 0.50% / Flow properties ● ● Film forming properties √ √ Drying time (hours) 8 8 Disk 1 Sample Point 1 Moisture 13.58% 14.23% Disk 1 Sample Point 2 Moisture 13.52% 14.31% Disk 1 Sample Point 3 Moisture 13.55% 14.26% Disk 1 Sample Point 4 Moisture 13.56% 14.27% Disk 1 Sample Point 5 Moisture 13.52% 14.26% Disk 15 Sample Point 1 Moisture 13.56% 14.26% Disk 15 Sample Point 2 Moisture 13.53% 14.29% Disk 15 Sample Point 3 Moisture 13.61% 14.25% Disk 15 Sample Point 4 Moisture 13.58% 14.29% Disk 15 Sample Point 5 Moisture 13.56% 14.30% Disk 30 Sample Point 1 Moisture 13.55% 14.27% Disk 30 Sample Point 2 Moisture 13.55% 14.28% Disk 30 Sample Point 3 Moisture 13.59% 14.27% Disk 30 Sample Point 4 Moisture 13.58% 14.25% Disk 30 Sample Point 5 Moisture 13.60% 14.28% Standard Deviation STDEV 0.03% 0.02% Average AVERAGE 13.56% 14.27% Coefficient of Variation CV 0.20% 0.15%

[0129] From Table 4, it can be seen that for compositions 17-18, the prepared glue solution has good fluidity and can form a film to form a rubber skin. In the preparation of algal oil soft capsules, the drying time is about 8 hours. The moisture values of the 5 sampling points of each tray from bottom to top, the 1st tray, the 15th tray, and the 30th tray are close, the CV is less than 10%, the data is highly stable, and the uniformity is very good.

[0130] Example 5: Effect of acid-treated starch of different sources, different gelatinization viscosities, and different phosphate contents on the determination results.

[0131] According to the formulations of compositions 19-20 in Table 5, the rubber skin was formed as described in the above method, and algal oil soft capsules were prepared with algal oil as the core liquid. The drying environment was 25°C and 18% humidity. The fluidity of the glue solution, film-forming property, drying time, moisture value uniformity, and stability of the film-forming composition were evaluated.

[0132] Composition 19 selected acid-treated pea starch with a gelatinization viscosity of 189 mPa·s and a phosphate group content of 0.054% (calculated as phosphorus P). Composition 20 selected acid-treated wheat starch with a gelatinization viscosity of 167 mPa·s and a phosphate group content of 0.046% (calculated as phosphorus P).

[0133] Table 5: Effect of acid-treated starch of different sources, different gelatinization viscosities, and different phosphate contents on the determination results.​​​​​

[0134] Composition Composition 19 Composition 20 Acid treated pea starch gelatinization viscosity 189 mPa s phosphorus content 0.054% 158.88 / Acid treated wheat starch gelatinization viscosity 167 mPa s phosphorus content 0.046% / 189.54 Glycerin 100.00 100.00 Water 85.00 85.00 Flowability ● ● Film forming property √ √ Drying time (hours) 8 6 Disk 1 Sample Point 1 Moisture 14.15% 13.64% Disk 1 Sample Point 2 Moisture 14.21% 13.71% Disk 1 Sample Point 3 Moisture 14.10% 13.66% Disk 1 Sample Point 4 Moisture 14.28% 13.68% Disk 1 Sample Point 5 Moisture 14.31% 13.74% Disk 15 Sample Point 1 Moisture 14.21% 13.71% Disk 15 Sample Point 2 Moisture 14.03% 13.64% Disk 15 Sample Point 3 Moisture 14.17% 13.73% Disk 15 Sample Point 4 Moisture 14.16% 13.74% Disk 15 Sample Point 5 Moisture 14.24% 13.71% Disk 30 Sample Point 1 Moisture 14.18% 13.59% Disk 30 Sample Point 2 Moisture 14.16% 13.57% Disk 30 Sample Point 3 Moisture 14.16% 13.66% Disk 30 Sample Point 4 Moisture 14.28% 13.72% Disk 30 Sample Point 5 Moisture 14.27% 13.68% Standard Deviation STDEV 0.07% 0.05% Average AVERAGE 14.19% 13.68% Coefficient of Variation CV 0.53% 0.38%

[0135] From Table 5, it can be concluded that for compositions 19-20, the prepared glue solution has good flowability and can form a film to form a rubber skin. When preparing the algal oil soft capsule, the drying time is 6-8 hours. The moisture values of the 5 sampling points of each tray from bottom to top, the 1st tray, the 15th tray and the 30th tray are close, the CV is less than 10%, the data is highly stable, and the uniformity is very good.

[0136] Discussion

[0137] The present application finds that the starch-containing composition for preparing soft capsules has poor flowability of the feed liquid, the prepared soft capsules require a long drying time (more than 24 h) and need to be manually turned during the drying process to achieve uniform moisture drying effect. The plant-based soft capsules of the prior art are prepared by adding a water-retaining agent or physically heating during the preparation process to make them dry quickly, but the moisture is not uniform, and there is a risk of sticking, depression, etc. In order to overcome the shortcomings and deficiencies of the prior art, the present application controls the gelatinization viscosity of the acid-treated starch, mixes it with a plasticizer and water in a certain proportion to obtain a colloid with excellent flowability, forms a starch film-forming composition with a certain gel strength, and prepares a soft capsule, which has high water loss efficiency, fast drying speed, and the moisture value reaches the target value of 9-15% in 5-10 hours, without the need for manual turning, uniform moisture, and greatly reduced production cost.

[0138] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, which are all included in the protection scope of the present application.

Claims

1. A starch film-forming composition comprising: (1) 26-60 wt% of an acid-treated starch, 20-40 wt% of a plasticizer, and 15-40 wt% of water, and not comprising a second starch different from the acid-treated starch, or (2) 26-60 wt% of an acid-treated starch, 20-40 wt% of a plasticizer, 15-40 wt% of water, and 2-8 wt% of a second starch different from the acid-treated starch selected from one or more of hydroxypropyl starch, cross-linked starch, acetate starch, oxidized starch, and native starch; and wherein the acid-treated starch is an acid-treated starch having a pasting viscosity of 5-196 mPa-s as a result of the acid treatment, and the acid-treated starch has a phosphate ester content of 0.01-0.06% as phosphorus; and wherein the pasting viscosity is a viscosity value of the starch paste at the pasting temperature determined by preparing a 10% w / w starch solution of the acid-treated starch with water using a rotational rheometer.

2. The starch film-forming composition according to claim 1, wherein the acid-treated starch is one or more of acid-treated corn starch, acid-treated pea starch, acid-treated potato starch, and acid-treated wheat starch, and / or the acid-treated starch is amylose and / or amylopectin; and / or the plasticizer is one or more of glycerol, propylene glycol, polyethylene glycol, sorbitol, erythritol, and maltitol; and / or the content of the plasticizer is 22-38 wt%; and / or the content of the water is 18-37 wt%.

3. The starch film-forming composition according to claim 1 or 2, further comprising one or more of a food gum, a colorant, and a flavoring.

4. The starch film-forming composition according to claim 3, wherein the starch film-forming composition satisfies one or more of the following conditions: (1) the content of the colorant and / or the flavoring is an acceptable content for soft capsules; (2) the food gum is one or more of gelatin, carrageenan, agar, sodium alginate, pectin, xanthan gum, and locust bean gum; and (3) the content of the food gum is 0.1-20 wt%.

5. The starch film-forming composition according to claim 1 or 2, wherein the starch film-forming composition does not comprise a food gum or the starch film-forming composition does not further comprise a water-retaining agent.

6. The starch film-forming composition according to claim 1 or 2, wherein the starch film-forming composition does not comprise gelatin or the starch film-forming composition does not comprise one or more of trehalose, mannitol, and xylitol.

7. A soft capsule shell comprising or prepared from the starch film-forming composition of any one of claims 1-6, the soft capsule shell having a water content of 9-15 wt%.

8. A method of preparing a soft capsule, comprising the steps of: (a) preparing a gel solution with a raw material comprising the starch film-forming composition of any one of claims 1-6, and forming the gel solution into a gel shell, (b) preparing the gel shell into a shaped soft capsule, and (c) drying the shaped soft capsule to a moisture content of 15% or less, to obtain a soft capsule; wherein the drying time of the shaped soft capsule is less than 10 hours.

9. The method according to claim 8, wherein the method meets one or more of the following conditions: (i) the drying time is 4-10 hours; (ii) the drying condition is ambient condition, or drying condition with temperature 20-25 °C and humidity 10-30%; (iii) the drying process is carried out under static condition or without turning the soft capsules; (iv) the drying method is tray drying method.

10. The method according to claim 8, comprising A) mixing water and plasticizer to obtain a premix, B) mixing the premix with acid treated starch to obtain a gel solution; C) preparing shaped soft capsules from the gel solution and drying the shaped soft capsules to below 15% moisture.

11. The method according to claim 10, further comprising one or more of the following steps: D) adding one or more of a second starch different from the acid treated starch, edible gum, pigment and flavor in step B); E) delivering the gel solution to a gel box of a soft capsule filling machine, spreading and cooling on a rotating drum to form a gel skin, filling the content during a mold cutting and suturing process to form a soft capsule.

12. The method according to claim 11, wherein the method comprises heating the mixture at 90-95 °C for 1-1.5 hours to obtain the gel solution; and / or drying the shaped soft capsules to 9-15% moisture; and / or the content is a powder or liquid active ingredient; and / or delivering the gel solution from a gel storage tank to the gel box through a gel pipe under gravity condition or under compressed air pushing at 0.05-0.1 MPa.

13. A soft capsule comprising a soft capsule shell according to claim 7 or prepared by the method of any one of claims 8-12, and further comprising a content.

14. Use of the soft capsule shell according to claim 7 or the soft capsule of claim 13 in food or cosmetics or in the preparation of a medicament.

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