Absorbable and high-stability algal oil soft candy and preparation method thereof

Abstract

The application discloses an easily-absorbed and high-stability algal oil soft candy and a preparation method thereof, and belongs to the field of food processing. The algal oil is double-embedded by OSA starch and sodium alginate-high methoxyl gellan gum, and the algal oil soft candy is prepared, so that the problem of easy oxidation of the algal oil soft candy prepared by using gelatin and other gel agents is overcome. The preparation method improves the stability and flavor characteristics of the algal oil soft candy, and the algal oil soft candy is easy to digest and absorb, the application of the algal oil as a nutritional fortifier in gel food is widened, and the algal oil soft candy has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of easy absorption, high stability algal oil soft candy and its preparation method, belong to food processing field. BACKGROUND

[0002] Docosahexaenoic acid (DHA) is a kind of ω-3 series polyunsaturated fatty acid which is difficult for human body to synthesize itself, has important significance for promoting growth and development, maintaining normal physiological activities, and is known as "brain gold". With the continuous improvement of residents' living standards, people's health awareness is also gradually enhanced, and more and more people realize the importance of DHA to human body, and the intake of DHA and its functional food have also been more widely concerned. Algal oil has the advantages of high DHA content, low heavy metal pollution and weak fishy smell, and is widely used in various functional foods. Microcapsule embedding technology refers to the encapsulation of some biologically active substances with reactivity, sensitivity and volatility to avoid loss of function during processing, storage and transportation. Common algal oil microcapsule delivery systems include liposomes, spray-dried microcapsules, nanoemulsions and gel soft candies.

[0003] Liposomes are spherical vesicles with bilayer structure formed by self-assembly of phospholipids dispersed in water. Different preparation processes will affect the size and layer of the vesicles, so the size distribution is wide, generally from tens of nanometers to several microns. Spray-dried microcapsules are a technology that converts fluid state to dry powder by spraying emulsion into hot drying medium. Patent CN107836716B discloses a method for microencapsulating algal oil by spray drying, in which algal oil is sheared and emulsified with maltodextrin, corn syrup and octenyl succinate starch HI-CAP100 solution at 60℃, and algal oil microcapsule particles are prepared after spray drying at an inlet air temperature of 190℃ and an outlet air temperature of 90℃. Emulsion refers to a food colloidal system composed of water, oil and emulsifier, i.e. oil phase is uniformly dispersed in water phase in the form of droplets. Gel soft candy refers to a type of candy with hardness and water content between hard candy and jelly. Gelatin is cross-linked by non-covalent interactions such as hydrogen bonding, hydrophobic interaction and electrostatic interaction, forming a three-dimensional network structure that acts as a framework in soft candy. Patent CN104543274A discloses a preparation method of DHA gel soft candy, in which DHA oil powder solution and sol are added to a sugar-containing solution heated and cooled to 50-100℃, and stirred uniformly, and then left to obtain the product.

[0004] Due to the high unsaturation of the algal oil, the DHA in the algal oil is extremely easy to be oxidatively degraded when the temperature is higher than 60℃, and the direct addition of the algal oil to food is easy to cause the rancidity and peculiar smell of the product, reduce the sensory quality of the food, and seriously restrict the application and effect of the algal oil. The above methods all have the problem that the high processing temperature is easy to cause the oxidative degradation of the DHA in the algal oil, produce aldehyde, ketone, alcohol and other secondary oxidation products, thereby generate bad flavors such as rancidity and fishy smell, and affect the sensory quality of the product. In addition, the oxidative degradation of the DHA also causes the loss of the original nutrition and health care value of the DHA, and the oxidative degradation products are also harmful to the human body. Therefore, it is an urgent problem to be solved to develop an embedding method which can reduce the oxidative degradation of the algal oil, enable long-term storage of the algal oil, and improve the flavor of the algal oil product, and the embedding method has good application prospect. SUMMARY

[0005] In order to solve the problems of easy oxidation of the algal oil and poor flavor of the prepared product, the algal oil is used as a core material, the octenyl succinate starch (OSA starch) is used as a wall material, the sucrose, sodium alginate, high methoxyl pectin, D-gluconic acid-delta-lactone and water are used as a gelling agent, the core material is dispersed in the wall material to be primarily encapsulated, the algal oil emulsion which is primarily encapsulated is injected into the gelling liquid to be encapsulated again, and through the optimization of the formula and the preparation process, the algal oil soft candy with strong stability and easy digestion is obtained. The sodium alginate-high methoxyl pectin-algal oil soft candy prepared by the method has the problem of easy oxidation of the algal oil soft candy prepared by using gelatin as a gelling agent is overcome, and the stability and flavor characteristics of the algal oil soft candy are improved. The method not only improves the environmental tolerance of the algal oil, but also can widen the application of the algal oil as a nutritional fortifier in gelling food.

[0006] A first object of the present application is to provide a method for embedding algal oil, comprising the following steps:

[0007] The denatured starch solution is configured and the algal oil is embedded to obtain an algal oil emulsion, and then the algal oil emulsion is mixed with a gelling liquid to obtain an algal oil emulsion gel after standing at room temperature for 18 hours; wherein the gelling liquid comprises sucrose, sodium alginate, high methoxyl pectin, D-gluconic acid-delta-lactone and water, the content of sucrose in the algal oil emulsion gel is 60% to 70% w / w, the total content of sodium alginate and high methoxyl pectin in the algal oil emulsion gel is 2% to 4% w / w, and the content of D-gluconic acid-delta-lactone in the algal oil emulsion gel is 1% to 2% w / w.

[0008] In an embodiment, the temperature for embedding the algal oil with the gelling liquid is 15 to 25℃ (room temperature).

[0009] In an embodiment, the content of sucrose is 60% to 65% w / w.

[0010] Alternatively, the content of sucrose is 60% or 65% w / w.

[0011] In an embodiment, the sodium alginate is added in an amount of 1.2-1.8% w / w.

[0012] In an embodiment, the high methoxyl pectin is added in an amount of 1.2-1.8% w / w.

[0013] Optionally, the mass ratio of sodium alginate to high methoxyl pectin is 3:2, 1:1, or 2:3.

[0014] Optionally, the sodium alginate and high methoxyl pectin together account for 3% w / w of the total algal oil emulsion gel system.

[0015] In an embodiment, the D-gluconic acid-delta-lactone is added in an amount of 1% w / w, 1.5% w / w, or 2% w / w.

[0016] In an embodiment, the modified starch is OSA starch, which is per 46 type or per-2015 type or per-2017 type (purchased from Shanghai Songqin Food Co., Ltd.).

[0017] Optionally, the OSA starch is per 46 type.

[0018] In an embodiment, the OSA starch is added in an amount of 2-4% w / w in the OSA starch solution.

[0019] In an embodiment, the algal oil emulsion is obtained by mixing the OSA starch solution and algal oil in a mass ratio of 8-10:1.

[0020] Optionally, the OSA starch solution and algal oil are mixed in a mass ratio of 9:1.

[0021] In an embodiment, the algal oil emulsion accounts for 5-15% w / w of the total algal oil emulsion gel system.

[0022] Optionally, the algal oil emulsion accounts for 5% w / w of the total algal oil emulsion gel system.

[0023] In an embodiment, the edible flavoring and edible pigment are added to the gel solution, and the amount of each of the edible flavoring and edible pigment is 0.1-0.5 μL / (g of total system).

[0024] In an embodiment, the flavoring is orange flavoring, and the pigment is orange edible pigment.

[0025] A second object of the present application is to provide use of any of the above algal oil emulsion gels in the preparation of algal oil products.

[0026] In an embodiment, the algal oil product is a health care product or food.

[0027] In an embodiment, the algal oil product comprises a candy or a capsule.

[0028] A third object of the present application is to provide an algal oil emulsion gel prepared by the above method.

[0029] In one embodiment, the algal oil emulsion gel can be used as a soft candy.

[0030] The present application also provides an algal oil soft candy, which contains the above algal oil emulsion gel or is further processed from the above algal oil emulsion gel.

[0031] In one embodiment, the algal oil soft candy further contains one or more of fruit juice extract, probiotic, prebiotic, vitamins and minerals, cellulose, flavoring agent.

[0032] In one embodiment, the method for preparing the algal oil soft candy specifically comprises the following steps:

[0033] (1) Preparation of algal oil emulsion: dissolve Per 46 type OSA starch in water at a concentration of 2% to 5% w / w, heat in a constant temperature water bath at 80 to 100°C for 20 to 40 min, and cool to 15 to 25°C (room temperature); mix the OSA starch solution with algal oil at a mass ratio of 8 to 10:1, and high-speed shear at 10000 to 12000 r / min for 3 to 5 min to prepare the algal oil emulsion.

[0034] (2) Preparation of gel liquid: dissolve sucrose, sodium alginate, high methoxyl pectin and D-gluconic acid-δ-lactone in water at room temperature, add orange flavoring and orange food coloring, and fully stir to obtain the gel liquid.

[0035] (3) Mixing and pouring: mix the algal oil emulsion and the gel liquid at a mass ratio of (5 to 15):(85 to 95) to obtain a mixture, pour the mixture into a mold (1.5 cm x 1.5 cm x 1 cm), wherein the addition amount of the algal oil emulsion accounts for 5% w / w of the total system, the addition amount of sucrose accounts for 60% to 70% w / w of the total system, the addition amount of sodium alginate accounts for 1.2% to 1.8% w / w of the total system, the addition amount of high methoxyl pectin accounts for 1.2% to 1.8% w / w of the total system, the addition amount of D-gluconic acid-δ-lactone accounts for 1% to 2% w / w of the total system, and the addition amounts of orange flavoring and orange food coloring are both 10 to 50 μL / (g of the total system), and after standing at 15 to 25°C (room temperature) for 16 to 20 h, the algal oil soft candy is demolded.

[0036] A fourth object of the present application is to provide a method for delaying the oxidation of algal oil, comprising the following steps:

[0037] The denatured starch solution is configured and the algal oil is embedded to obtain an algal oil emulsion, and then the algal oil emulsion is mixed with a gel solution, and after standing at room temperature for 18 hours, an algal oil emulsion gel is obtained; wherein the gel solution comprises sucrose, sodium alginate, high methoxyl pectin, D-glucaric acid-delta-lactone and water, the sucrose accounts for 60-70% w / w of the algal oil emulsion gel, the sum of the sodium alginate and the high methoxyl pectin accounts for 2-4% w / w of the algal oil emulsion gel, and the D-glucaric acid-delta-lactone accounts for 1-2% w / w of the algal oil emulsion gel.

[0038] The application also provides a method for improving the digestion and absorption of algal oil, comprising the following steps:

[0039] The denatured starch solution is configured and the algal oil is embedded to obtain an algal oil emulsion, and then the algal oil emulsion is mixed with a gel solution, and after standing at room temperature for 18 hours, an algal oil emulsion gel is obtained; wherein the gel solution comprises sucrose, sodium alginate, high methoxyl pectin, D-glucaric acid-delta-lactone and water, the sucrose accounts for 60-70% w / w of the algal oil emulsion gel, the sum of the sodium alginate and the high methoxyl pectin accounts for 2-4% w / w of the algal oil emulsion gel, and the D-glucaric acid-delta-lactone accounts for 1-2% w / w of the algal oil emulsion gel.

[0040] Beneficial effects

[0041] The algal oil soft candy prepared by the application overcomes the problem that the algal oil soft candy prepared by using gelatin and other gel agents is easy to be oxidized, improves the stability and flavor characteristics of the algal oil soft candy, increases the environmental tolerance of the algal oil, and is beneficial to digestion and absorption. The specific beneficial effects are as follows:

[0042] (1) The algal oil is double-embedded in the form of emulsion gel by using OSA starch and sodium alginate-high methoxyl pectin in the application, the stability of the embedded algal oil is improved, and the oxidation speed is slowed down; specifically, under the storage condition of 45 DEG C, the algal oil soft candy of the application is reduced by 20.3% compared with the algal oil, and is reduced by 79.9% compared with the traditional gelatin type algal oil soft candy on the 15th day;

[0043] (2) The algal oil soft candy prepared by the application has good hardness, chewiness and other texture parameters, wherein the chewiness is 855g; the addition of orange flavor essence can enrich the aroma and taste of the algal oil soft candy, has a good masking effect on the original bad flavor of the algal oil, has a good sensory evaluation, and is more popular with consumers;

[0044] (3) The algal oil soft candy prepared by the application has better intestinal absorption, the release rate in gastric juice is less than 5%, the release rate in intestinal juice reaches 75%, and it is more beneficial to the absorption and utilization of DHA by the human body. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1Physical stability of algal oil emulsion prepared with different types of OSA starch, wherein a is per 46 type; b is per-2015 type; c is per-2017 type;

[0046] Figure 2 Physical stability of algal oil emulsion prepared with different concentrations of per 46 type OSA starch, wherein a is 2%; b is 3%; c is 4%; d is 5%;

[0047] Figure 3 Pictures of soft candies prepared with different mass ratios of sodium alginate and high methoxyl pectin, wherein a is sodium alginate: high methoxyl pectin = 2:3; b is sodium alginate: high methoxyl pectin = 1:1; c is sodium alginate: high methoxyl pectin = 3:2;

[0048] Figure 4 Pictures of sensory evaluation of soft candies under different formulations;

[0049] Figure 5 Effect of algal oil emulsion addition amount on sensory evaluation of soft candies;

[0050] Figure 6 DHA release rate of algal oil soft candy in simulated digestive fluid. DETAILED DESCRIPTION

[0051] The following describes the preferred embodiments of the present application, and it should be understood that the embodiments are for better explaining the present application and are not used to limit the present application.

[0052] The detection methods used in the embodiments are as follows:

[0053] 1. Physical stability analysis method

[0054] A dispersion analyzer (LUMiSizer 651, LUM Company, Germany) was used to reflect the stability of the algal oil emulsion.

[0055] Specifically, 1.8 mL of sample was injected into a polycarbonate tube (PC tube) sample dish with an optical path of 2 mm, placed flat in the instrument, and the transmittance was measured. The centrifugal stability of the sample was analyzed by the transmittance curve of the sample at different times. The movement rate of particles in the emulsion was accelerated by centrifugation to predict the physical stability of the sample under long-term storage conditions. The experimental parameters were set as follows: the test light source was a red light source with a wavelength of 865 nm, the light factor was 1, the centrifugal rate was 4000 r / min, the contour line was 400, the test time interval was 20 s, and the total test time was 2.5 h. The stability of the sample can be reflected by observing the change in light transmittance at different positions of the same sample.

[0056] 2. Texture analysis method

[0057] A cylindrical aluminum probe with a diameter of 35 mm (P / 35) was used to test the gel cuboid with a length of 15 mm, a width of 15 mm, and a height of 10 mm twice. The pressure measuring element of the texture analyzer (TA-XTplus, British SMS Company) was 30 kg, and the speed before, during and after the test was 1 mm / s, and the deformation was 50%. Finally, the parameters such as hardness, elasticity, chewiness and adhesion were recorded. All measurements were determined seven times.

[0058] The texture of the soft candy is an important factor affecting consumer preference, and the market performance of the gel soft candy is highly dependent on the texture characteristics of the soft candy. Soft candy with moderate hardness, high elasticity, high chewiness and low stickiness has better acceptance. The existing dissertation "Gelatin soft candy formula optimization for the purpose of improving thermal stability and taste" found that soft candy with a hardness of about 900-1200 g and a chewiness of about 800-1100 g is more popular with consumers.

[0059] 3. Sensory quality evaluation method

[0060] The 9-point hedonic scale is a commonly used scale for testing consumer preference and acceptability of food. The scale consists of 9 preference description points, 1 "extremely dislike", 2 "very dislike", 3 "moderate dislike", 4 "slight dislike", 5 "neither like nor dislike", 6 "slight like", 7 "moderate like", 8 "very like", 9 "extremely like". The present application analyzes the appearance, color, aroma, texture and overall acceptance of the sample soft candy prepared under different ratio conditions by a consumer group using the 9-point hedonic method. The consumer group consists of 50 members, aged between 18 and 60 years old. The samples are prepared on the day of the test and placed in a constant temperature of 25℃. Each sample is given a three-digit random number. When evaluating different samples, the consumer personnel need to rinse their mouth with pure water and chew tasteless biscuits, then breathe evenly for 30s to restore the sense of taste, and breathe evenly for 8min to restore the sense of smell. All experiments were carried out in a standard sensory laboratory.

[0061] 4. Storage experiment and oxidation stability experiment method of algal oil soft candy

[0062] The prepared algal oil soft candy sample was placed in an oven at 45℃ for accelerated oxidation, and stored for 15 days, and the lipid oxidation products of the sample were determined every 3 days. Lipid peroxide is a key marker of lipid oxidation products, and the peroxide value is used to reflect it.

[0063] Specifically: take 2 g of soft candy sample, add appropriate amount of deionized water (about 5 g) 70 ℃ water bath for 10 min, make the soft candy completely dissolved. Cool to room temperature, add isooctane-isopropyl alcohol 1.5 mL (3:1, v / v), vortex for 30 s, centrifuge at 10000 g for 5 min. Take 0.2 mL of the upper organic phase solution, add 2.8 mL of methanol / n-butanol (2:1, v / v), 10 μL of 3.94 mol / L thiocyanate solution, 10 μL of ferrous ion solution (0.132 mol / L BaCl2 solution and 0.144 mol / L FeSO4 solution mixed in a volume ratio of 1:1), vortex for 30 s, and immediately place in the dark for 20 min. Measure at 510 nm with UV1600 spectrophotometer to obtain the peroxide value content.

[0064] 5. In vitro simulated digestion method for studying the characteristics of algal oil soft candy

[0065] Preparation of simulated gastric juice: take 2 g of NaCl, 3.2 g of pepsin and 7 mL of concentrated hydrochloric acid, dissolve in 250 mL of deionized water, adjust the pH of the system to 1.30 (1.0 mol / L HCl), and dilute to 1000 mL.

[0066] Preparation of simulated intestinal juice: take 6.8 g of potassium dihydrogen phosphate, dissolve in 250 mL of deionized water, add 100 mL of 0.2 mol / L NaOH solution and 400 mL of deionized water, add 10 g of trypsin and 5 g of decholate, adjust the pH of the system to 7.0 (0.2 mol / L NaOH solution), and dilute to 1000 mL.

[0067] Specific method: add 50 mL of simulated gastric juice and simulated intestinal juice respectively in a 100 mL beaker, and place in a 37 ℃ water bath shaker for constant temperature for 30 min. Cut the soft candy sample into small pieces with a size of about 5 mm x 5 mm x 5 mm, add 4 g of algal oil soft candy to the digestion solution, adjust the shaker parameters to 100 r / min, take 2 mL of sample at 10, 20, 30, 45, 60, 90 and 120 min respectively, and then supplement the same volume of digestion solution at the same temperature.

[0068] Determine the DHA content according to GB / T 38095-2019 "Determination of DHA and EPA content by gas chromatography".

[0069] Specifically, the digestive juice is taken out immediately after the water film, a certain amount of digestive juice after the membrane is accurately taken into a 10 mL centrifuge tube, 2 mL of 0.5 mol / L sodium hydroxide-methanol solution is added, 60℃ water bath for 30 min, cooling, 2 mL of 25% BF3-methanol solution is added, 60℃ water bath for 20 min, cooling, 2 mL of n-hexane is added, shaking, then 2 mL of saturated NaCl solution is added, shaking, taking the upper organic phase, adding a small amount of anhydrous sodium sulfate, taking the clear liquid through the organic membrane, and performing gas chromatography analysis.

[0070] Gas chromatography conditions: injection volume: 1 μL; vaporization chamber temperature: 250℃; column flow: 3 mL / min; N2purge flow: 3 mL / min; split ratio: 5:1; column temperature: 120℃; column oven gradient temperature: 120℃ (5 min), 10℃ / min to 190℃ (1 min), 2℃ / min to 230℃ (17 min); column: DB-WAX (30 m x 0.25 mm x 0.25 μm); detector temperature: 260℃; tail gas: N2, 30 mL / min; H2: 40 mL / min; air: 400 mL / min.

[0071] The DHA content in the digestive juice is determined by a GC-2010PLUS type gas chromatograph (full automatic liquid / headspace), and the cumulative release rate calculation formula is as follows:

[0072]

[0073] In the formula: C n is the concentration of DHA in the digestive juice system at the nth sampling, μg / mL; V is the total volume of the release system, mL; C i is the component concentration in the system at the ith sampling, μg / mL; V s is the volume of each sampling, mL; m is the total content of the components in the sample.

[0074] 6. Material source

[0075] per 46 type or per-2015 type or per-2017 type OSA starch is purchased from Shanghai Songqin Food Co., Ltd.

[0076] Algal oil is purchased from Xi'an Zebang Biological Technology Co., Ltd.

[0077] Example 1: Preparation of algal oil emulsion gel and algal oil soft candy

[0078] I. Preparation of algal oil emulsion gel:

[0079] (1) Preparation of algal oil emulsion: dissolve per 46 type OSA starch (octenyl succinic anhydride starch) in water at a concentration of 4% w / w, heat in a constant temperature water bath at 90°C for 30 min, and cool to 15-25°C (room temperature); mix the OSA starch solution with algal oil at a mass ratio of 9:1, high-speed shear at 12000 r / min for 3 min, and prepare the algal oil emulsion.

[0080] (2) Preparation of gel solution: dissolve sucrose, sodium alginate, high-methoxyl pectin, and D-glucaric acid-delta-lactone in water at room temperature, and fully stir to obtain a uniform gel solution.

[0081] (3) Mixing: mix the algal oil emulsion and the gel solution at a mass ratio of 5:95, wherein the algal oil emulsion accounts for 5% w / w of the total system, the addition amount of sucrose is 65% w / w of the total system, the addition amount of sodium alginate is 1.8% w / w of the total system, the addition amount of high-methoxyl pectin is 1.2% w / w of the total system, and the addition amount of D-glucaric acid-delta-lactone is 2% w / w of the total system, and stand at room temperature for 18 h to obtain the algal oil emulsion gel.

[0082] II. Method for preparing algal oil soft candy using algal oil emulsion gel, comprising the following steps:

[0083] (1) Preparation of algal oil emulsion: dissolve per 46 type OSA starch (octenyl succinic anhydride starch) in water at a concentration of 4% w / w, heat in a constant temperature water bath at 90°C for 30 min, and cool to 15-25°C (room temperature); mix the OSA starch solution with algal oil at a mass ratio of 9:1, high-speed shear at 12000 r / min for 3 min, and prepare the algal oil emulsion.

[0084] (2) Preparation of gel solution: dissolve sucrose, sodium alginate, high-methoxyl pectin, and D-glucaric acid-delta-lactone in water, and add orange flavoring and orange food coloring, fully stir to obtain a uniform gel solution.

[0085] (3) Mixing and pouring: mix the algal oil emulsion and the gel solution at a mass ratio of 5:95, wherein the algal oil emulsion accounts for 5% w / w of the total system, the addition amount of sucrose is 65% w / w of the total system, the addition amount of sodium alginate is 1.8% w / w of the total system, the addition amount of high-methoxyl pectin is 1.2% w / w of the total system, the addition amount of D-glucaric acid-delta-lactone is 2% w / w of the total system, and the addition amount of orange flavoring and orange food coloring is 50 μL / (g total system), pour into a mold (1.5 cm x 1.5 cm x 1 cm), and stand at room temperature for 18 h, then demold to obtain the algal oil soft candy.

[0086] Example 2: Optimization of algal oil soft candy embedding conditions

[0087] 1. Algal oil emulsion optimization

[0088] (1) Wall material type optimization

[0089] In step (1) of Example 1, 2% w / w per 46, per-2015 and per-2017 OSA starches were taken in 100 mL deionized water.

[0090] The dispersion analyzer was used to centrifuge test the algae oil emulsion to accelerate the occurrence of instability, so as to analyze the stability effect of different types of OSA starches.

[0091] Figure 1 is a diagram showing the evolution of the transmittance curve over time, the abscissa represents the top (110 mm) and bottom (130 mm) of the sample tube, and the ordinate represents the transmittance of the sample to the incident light. As the analysis time increases, the contour line will change from red to green. By observing the change in light transmittance at different positions of the same sample, the stability of the sample can be reflected. From Figure 1 It can be seen that the algae oil emulsion stabilized by per 46 OSA starch only showed an increase in light transmittance (from 5% to 75%) at the lower part (120-130 mm) of the PC tube, indicating that the emulsion showed a cream layer at the upper layer and a water layer at the lower layer. The algae oil emulsion stabilized by per-2015 and per-2017 OSA starches showed an increase in light transmittance (from 5% to 60% and 85%) throughout the PC tube, indicating that the water and oil phases in the emulsion were separated, with the oil phase at the upper layer and the water phase at the lower layer. It can be seen that the per 46 OSA starch has better stability for embedding algae oil than the per-2015 and per-2017 OSA starches, and therefore, the per 46 OSA starch is selected as the wall material for embedding algae oil.

[0092] (2) Wall material addition amount optimization

[0093] In step (1) of Example 1, per 46 OSA starch aqueous solutions with concentrations of 2% w / w, 3% w / w, 4% w / w and 5% w / w were prepared to prepare algae oil emulsions, and the detection method was consistent with step (1) to detect the stability of the emulsion.

[0094] The dispersion analyzer was used to centrifuge test the algae oil emulsion to accelerate the occurrence of instability, so as to analyze the stability effect of different OSA starch addition amounts.

[0095] From Figure 2It can be seen that when the starch concentration is 4% w / w, the profile of the system changes less, and the transmittance at the bottom of the sample only increases from 5% to about 30%, indicating that the stability of the system is better. When the starch concentration is 2% and 3% w / w, the profile of the system changes greatly, and the transmittance at the bottom of the sample increases from 5% to about 75% and 65%, respectively. The increase in clarity at the bottom of the sample indicates that the stability of the emulsion becomes worse. This may be because the concentration of OSA starch is too low to cover the entire surface of the oil droplets, so that aggregation or flocculation occurs between the droplets. When the starch concentration is 5% w / w, the transmittance at the bottom of the sample increases from 5% to about 40%. At this time, the concentration of OSA starch is too high, and the interaction between the excess unabsorbed OSA starch and the OSA starch adsorbed on the surface of the oil droplets disturbs the adsorption and rearrangement of the OSA starch on the interface, thereby leading to flocculation of the emulsion. Therefore, 4% w / w per 46 type OSA starch is selected for subsequent experiments.

[0096] 2. Optimization of gel embedding conditions

[0097] (1) Optimization of sucrose addition amount

[0098] In step (1) of Example 1, the amount of sucrose added was changed to 60% w / w, 65% w / w, and 70% w / w, respectively, and the remaining conditions were consistent with Example 1. Algal oil soft candies were prepared.

[0099] In the preparation process of the present application, sucrose is added to promote the formation of sodium alginate-high methoxyl pectin gel. By optimizing the amount of sucrose, soft candies with good texture are obtained. The texture of soft candies with different sucrose addition amounts is shown in Table 1.

[0100] As can be seen from Table 1, as the amount of sucrose increases, the hardness and chewiness of the soft candy increase, and the adhesiveness decreases significantly. When the sucrose addition amount is 60% w / w and 65% w / w, the elasticity of the sample has no significant difference. When the sucrose addition amount is 70% w / w, the elasticity of the sample is significantly smaller than that of the other two groups. The reason is that sucrose competes with colloid molecules for hydration water, and as the amount of sucrose increases, the hydrophobic interaction between high methoxyl pectin methyl esters increases, thereby increasing the interaction between sodium alginate and high methoxyl pectin molecules, increasing the gel strength and hardness, and decreasing the elasticity. Therefore, the hardness of the soft candy with a sucrose addition amount of 60% w / w is too small, and the hardness of the soft candy with a sucrose addition amount of 70% w / w is too large. In summary, the preferred sucrose addition amount is 65% w / w.

[0101] Table 1 Effect of sucrose addition amount on the texture of soft candy

[0102]

[0103] (2) Optimization of gel ratio

[0104] In step (1) of Example 1, the total mass fraction of the system colloid (sodium alginate and high methoxyl pectin) was kept at 3% w / w, the mass ratio of sodium alginate to high methoxyl pectin was changed to 3:2, 1:1 and 2:3, and the remaining conditions were consistent with Example 1, to prepare gummies, and the gummy texture is shown in Table 2.

[0105] Table 2 Effect of mass ratio of sodium alginate to high methoxyl pectin on gummy texture

[0106]

[0107] As can be seen from Table 2, as the proportion of sodium alginate in the total colloid increases, the hardness and chewiness of the gummy increase, but the elasticity and adhesiveness do not change significantly. In addition, the gel strength of the system is also related to the degree of methylation of high methoxyl pectin. When the mass ratio of sodium alginate to high methoxyl pectin is 2:3, the hardness is too low, the gel strength is poor, and it is not easy to demold. The results are shown in Table 2. Therefore, the formulations with a mass ratio of 1:1 and 3:2 are selected for subsequent experiments. Figure 3

[0108] (3) Optimization of D-gluconic acid-δ-lactone addition

[0109] In step (1) of Example 1, the D-gluconic acid-δ-lactone addition was configured to be 1% w / w, 1.5% w / w, and 2% w / w, and the remaining conditions were consistent with Example 1, to prepare gummies, and the gummy texture is shown in Table 3.

[0110] As can be seen from Table 3, as the D-gluconic acid-δ-lactone addition increases, the hardness and chewiness of the gummy increase, and the adhesiveness decreases, but the D-gluconic acid-δ-lactone addition has no significant effect on the elasticity of the sample.

[0111] pH is one of the key factors affecting the formation of sodium alginate-high methoxyl pectin gel. The conditions for high methoxyl pectin to form gel are pH 2.0-3.5, the conditions for sodium alginate to form gel are pH <4.0, and the conditions for sodium alginate-high methoxyl pectin system to form gel are pH <4.0. D-gluconic acid-δ-lactone as a mild acidifying agent can slowly hydrolyze into D-gluconate and release H + + in water at room temperature, thereby reducing the pH of the system, and reaching dissociation equilibrium at about 160 min. When the pH of the system is low enough, the carboxylate group combines with H + to convert to a carboxylic acid group, the molecule is no longer charged, the repulsion between colloid molecules decreases, the degree of hydration decreases, the hydrophobic interaction increases, and the interaction between colloid molecules increases, which is conducive to the association between molecules to form a gel. The hardness of the gummy with a D-gluconic acid-δ-lactone addition of 1% w / w is too small. Therefore, in summary, the D-gluconic acid-δ-lactone addition of 1.5% w / w and 2.0% w / w is selected for subsequent experiments.​

[0112] Table 3D - Effect of D-glucono-δ-lactone on gummy texture

[0113]

[0114] (4) Effect of different gelatinous agent ratio on gummy flavor and texture

[0115] The different gelatinous agent formulations are as follows:

[0116] Sample 1 : Based on Example 1, the amount of sodium alginate was modified to 1.5% w / w, the amount of high methoxyl pectin was modified to 1.5% w / w, and the amount of D-glucono-δ-lactone was modified to 1.5% w / w.

[0117] Sample 2: Based on Example 1, the amount of sodium alginate was modified to 1.5% w / w, the amount of high methoxyl pectin was modified to 1.5% w / w, and the amount of D-glucono-δ-lactone was modified to 2% w / w.

[0118] Sample 3: Based on Example 1, the amount of D-glucono-δ-lactone was modified to 1.5% w / w.

[0119] Sample 4: Consistent with Example 1.

[0120] Gummies were prepared from the four samples, and a 9-point hedonic scale was used to evaluate the appearance, color, flavor, texture, and overall acceptance of the four samples. The results are shown in Table 5. There were no significant differences in appearance, color, and flavor among the four samples, but there were significant differences in texture. Figure 4 Sample 4 had the highest sensory score and the highest overall acceptance, indicating that this sample was more popular than the other samples in terms of hardness, elasticity, chewiness, and stickiness. This is consistent with the texture data, which is shown in Table 4. Only Sample 4 had a hardness between 900 and 1200 g, and Sample 4 had relatively large elasticity and relatively small adhesiveness, which were more consistent with the type of popular research.

[0121] In summary, the formula for sodium alginate-high methoxyl pectin gummies was determined to be 65% w / w sucrose, 1.8% w / w sodium alginate, 1.2% w / w high methoxyl pectin, 2% w / w D-glucono-δ-lactone, 50 μL / (g total system) orange flavor, and 50 μL / (g total system) food color and water.

[0122] Table 4 - Effect of different formulations on gummy texture

[0123]

[0124] ​

[0125] 3. Optimization of the amount of algal oil emulsion added

[0126] The mass ratio of algal oil emulsion to gelling solution was changed to 5:95, 10:90, and 15:85, respectively. After being stirred thoroughly, the mixture was poured into a mold (1.5 cm x 1.5 cm x 1 cm). The remaining conditions were the same as in Example 1. After being left to stand at room temperature for 18 h, the algal oil soft candy was removed from the mold. The effect of the amount of algal oil emulsion added on the texture and sensory evaluation was detected.

[0127] It can be found from Table 4 that the addition of algal oil emulsion has a greater impact on the sensory score of the soft candy. When no algal oil emulsion is added, the smell of the soft candy is mainly the smell of orange flavoring, with a faint orange smell. When 5% w / w algal oil emulsion is added, there is a faint fishy smell in the faint orange smell, but when too much algal oil emulsion is added, the fishy smell of the algal oil itself becomes stronger, producing a pungent smell, which reduces the acceptance in terms of flavor and taste. In summary, the algal oil soft candy with 5% w / w algal oil emulsion has the highest sensory score, and this content is the optimal amount of algal oil emulsion added. Figure 5 Table 5. Effect of the amount of algal oil emulsion added on the texture of the soft candy

[0128]

[0129] As can be seen from the texture data in Table 5, the hardness and chewiness of the soft candy after the addition of algal oil are significantly improved. This may be because the algal oil emulsion contains a small amount of OSA starch, which, as a long-chain polysaccharide, has similar properties to sodium alginate and high-methoxyl pectin, and can also form intramolecular and intermolecular hydrogen bonds, increasing the cross-linking in the gel system and further enhancing the gel strength. At the same time, since the emulsion replaces part of the water in the formula, the water content in the system is reduced and the solid content is increased, which may also lead to an increase in hardness and chewiness.

[0130] Therefore, the formula of the sodium alginate-high-methoxyl pectin-algal oil soft candy is determined to be: 65% w / w sucrose, 1.8% w / w sodium alginate, 1.2% w / w high-methoxyl pectin, 2% w / w D-gluconic acid-delta-lactone, 50 μL / (g total system mass) of orange flavoring, and 50 μL / (g total system mass) of food coloring, 5% w / w algal oil emulsion, and water.

[0131] Example 3: In vitro digestion utilization rate of algal oil

[0132] The algal oil soft candy prepared in Example 1 was taken to detect its digestion.

[0133]

[0134] ​The small intestine is the target digestive organ for DHA, and after the DHA in the algae oil soft candy is released, it is carried into the blood and lymph by chylomicrons in the small intestine. Therefore, controlling the release of DHA in the algae oil soft candy in the intestinal juice as much as possible is the basis for improving the DHA absorption rate. The algae oil soft candy is first chewed in the oral cavity by teeth and digested by saliva, then passes through the gastric juice, and finally reaches the small intestine to be absorbed and utilized by the human body. Because of the strong water-holding force of the gel structure, it is not easy to melt, and it stays in the human oral cavity for a short time, so the release of DHA in the algae oil soft candy in simulated gastric juice and simulated intestinal juice is mainly investigated.

[0135] The results, as shown in Figure 6 , with the extension of the digestion time, the release rate of DHA gradually increased. The release rate of DHA in the early stage of digestion in the simulated gastric juice (the first 30 min) was fast, and gradually stabilized in the later stage, and the final release rate was less than 5%. This is due to the fact that sodium alginate and high methoxyl pectin are difficult to be digested in the gastric juice, and both of them always maintain their original structure, and the sodium alginate-high methoxyl pectin gel can stably exist under the strong acidic conditions of the gastric juice. Under this environmental condition, the ionization degree of the carboxylic acid group is further reduced, the molecular chain is contracted, and the gel pore size is reduced, thereby preventing the release of emulsion particles, which is beneficial to protect the structure and function of DHA and improve its bioavailability.

[0136] However, in the first 20 min of intestinal juice digestion, the release rate of DHA increased rapidly. Thereafter, the upward trend gradually slowed down, and the final release rate was about 75%. This may be because under neutral conditions, the carboxylic acid group in the gel structure ionizes H + , the hydrogen bond is broken, the intermolecular repulsion increases, the hydrophobic interaction weakens, the gel swells, and the gel network structure is destroyed, thereby releasing the emulsion particles. The DHA in the algae oil soft candy shows significant differences in the digestion process in the gastric juice and the intestinal juice, with slow and small release in the gastric juice, and rapid and more complete release in the intestinal juice. This difference is very beneficial to the human body, and once the DHA is delivered in a structurally and functionally complete form to the small intestine, its digestion, absorption and bioavailability can be enhanced.

[0137] Comparative Example 1: Preparation of algae oil soft candy with other formulations

[0138] Accurately weigh 32.5 g of sucrose, 32.5 g of glucose, 1 g of sodium alginate, 1 g of high methoxyl pectin, 1 g of D-glucaric acid-delta-lactone, 50 μL of orange flavor and food colorant, 5 g of algae oil emulsion, and 25 g of deionized water, and prepare the algae oil soft candy by the same method as in Example 1, and detect its texture and sensory evaluation.

[0139] The texture detection shows that the hardness of the alginate oil lactose prepared by the formula is (861±33) g, the elasticity is 0.914±0.04, the chewiness is 431±35, and the adhesiveness is (-137±10) g, and the hardness is small and the chewiness is low.

[0140] The alginate oil soft candy prepared by the formula is compared with the alginate oil soft candy of the application by using the nine-point hedonic method, and the consumers think that the overall acceptance of the soft candy prepared by the formula is lower than that of the application, which is consistent with the data analysis result of the texture.

[0141] Comparative Example 2: Effect of different preparation methods on oxidation of alginate oil

[0142] The preparation method of the gelatin type alginate oil soft candy can refer to the dissertation “Study on Extraction and Physicochemical Properties of Rhus Chinensis Leaf Pectin”.

[0143] Take 8 g of gelatin in a beaker, add 16 g of water, stir uniformly, and place in a 80℃ water bath to heat to sol state, and keep warm. Weigh 30 g of melted sucrose and add 30 g of glucose syrup, and stir and cook until the solid content is about 78%. When the temperature of the sugar solution drops to 90℃, add the gelatin solution, acid, alginate oil emulsion, pigment and essence for blending, and stir uniformly. Pour the sugar solution into a silica gel mold, dry at low temperature, and demold to obtain gelatin alginate oil lactose.

[0144] Take the alginate oil soft candy prepared in Example 1, and use pure alginate oil, alginate oil soft candy prepared in Comparative Example 1, and conventional gelatin type alginate oil soft candy as comparison, to detect the oxidation of alginate oil, and the results are shown in Table 6.

[0145] Table 6 Change of peroxide value of alginate oil and alginate oil soft candy with storage time

[0146]

[0147]

[0148] As can be seen from Table 6, the initial peroxide value of the alginate oil soft candy prepared by the above three methods is higher than that of the alginate oil, because during the processing of the soft candy, the alginate oil is inevitably exposed to the environment, and factors such as oxygen, sunlight and high-speed dispersion cause the alginate oil to oxidize to a certain extent. The initial peroxide value of the gelatin type alginate oil lactose is the highest, and the temperature during its preparation is as high as 90℃, which will promote the alginate oil to oxidize at high intensity.

[0149] With the extension of storage time, the peroxide value of the algal oil and the three kinds of algal oil soft candies all have different degrees of increase. For the algal oil, the oxidation rate is slow in the first 6 days, and the oxidation rate becomes fast in 6-15 days. The soft candy of Example 1 is just the opposite, the oxidation rate is fast in the first 6 days, and the oxidation rate becomes slow in 6-15 days. This may be due to the fact that the algal oil contains natural antioxidants such as carotenoids at the beginning, which can inhibit the oxidation of the algal oil in the early stage of oxidation. But in the later stage of oxidation, these substances are consumed, and without their protection, the oxidation rate of the algal oil increases. For the soft candy of Example 1, although the initial processing process slightly accelerates the oxidation of the algal oil, making it contain more peroxide and free radicals, the free radicals promote the occurrence of the chain reaction of oil oxidation, resulting in a relatively fast initial oxidation rate, but its initial peroxide value is still far lower than that of the gelatin type algal oil soft candy. In the later stage of storage, due to the protection of the emulsion and the gel structure, the effect of environmental factors such as oxygen and free radicals is blocked, so the oxidation rate slows down.

[0150] The initial process of oxidation of the soft candy of Comparative Example 1 is similar to that of Example 1, but the later oxidation process is faster, which may be because the soft candy prepared from Comparative Example 1 is not compact and does not form a dense three-dimensional network structure, so it cannot well protect the internal algal oil in the later storage period, thereby causing the oxidation process to accelerate. For the gelatin type algal oil soft candy, when the sugar solution temperature is reduced to 90℃, the gelatin solution, algal oil emulsion and the like are added for blending, high temperature will promote the algal oil to begin to oxidize, and in the accelerated storage process, the free radical chain reaction will be further accelerated, thereby promoting the oxidation and degradation of the algal oil. In addition, as can be seen from Table 6, at 12 days, the peroxide value of the soft candy of Example 1 is already lower than that of the algal oil, proving that the gel structure can indeed delay the oxidation of the algal oil and has a long-term good protective effect on DHA. On the 15th day, the peroxide value of the soft candy prepared in Example 1 is reduced by 33.4% compared with the soft candy of Comparative Example 1, and by 79.9% compared with the gelatin type algal oil soft candy.

[0151] Combining the data of oxidation stability profile and sensory evaluation, it can be found that the algal oil soft candy prepared in Example 1 has the best stability, flavor and taste, and higher sensory acceptance.

[0152] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. A method for encapsulating algal oil, characterized in that, Includes the following steps: A modified starch solution was prepared and algal oil was encapsulated to obtain an algal oil emulsion. This emulsion was then mixed with a gelling agent and allowed to stand at room temperature for 18 hours to obtain the algal oil emulsion gel. The gelling agent comprised sucrose, sodium alginate, and high-methoxyl pectin. D -gluconic acid- δ - Lactones and water, sucrose account for 60%~70% w / w of the algal oil emulsion gel, and the total of sodium alginate and high-methoxyl pectin accounts for 2%~4% w / w of the algal oil emulsion gel. D -gluconic acid- δ - Lactones account for 1%~2% w / w of algal oil emulsion gels; The modified starch solution contains 2% to 4% w / w octenyl succinate starch ester; the algal oil emulsion is obtained by mixing the modified starch solution and algal oil at a mass ratio of 8 to 10:1 and then dispersing them at high speed; the algal oil emulsion accounts for 5% to 15% w / w of the algal oil emulsion gel.

2. An algal oil emulsion gel, characterized in that, The algal oil emulsion gel is prepared by the method described in claim 1.

3. The application of the algal oil emulsion gel according to claim 2 in the preparation of algal oil products.

4. An algal oil soft candy, characterized in that, The algal oil gummies contain the algal oil emulsion gel as described in claim 2.

5. The algal oil soft candy according to claim 4, characterized in that, The algal oil gummies also contain one or more of the following: fruit juice extract, probiotics, prebiotics, vitamins and minerals, cellulose, and flavoring agents.

6. A method for delaying the oxidation of algal oil, characterized in that, Includes the following steps: A modified starch solution was prepared and algal oil was encapsulated to obtain an algal oil emulsion. This emulsion was then mixed with a gelling agent and allowed to stand at room temperature for 18 hours to obtain the algal oil emulsion gel. The gelling agent comprised sucrose, sodium alginate, and high-methoxyl pectin. D -gluconic acid- δ - Lactones and water, sucrose account for 60%~70% w / w of the algal oil emulsion gel, and the total of sodium alginate and high-methoxyl pectin accounts for 2%~4% w / w of the algal oil emulsion gel. D -gluconic acid- δ - Lactones account for 1%~2% w / w of algal oil emulsion gels; The modified starch solution contains 2% to 4% w / w octenyl succinate starch ester; the algal oil emulsion is obtained by mixing the modified starch solution and algal oil at a mass ratio of 8 to 10:1 and then dispersing them at high speed; the algal oil emulsion accounts for 5% to 15% w / w of the algal oil emulsion gel.

7. A method for improving the digestibility and absorption of algal oil, characterized in that, Includes the following steps: A modified starch solution was prepared and algal oil was encapsulated to obtain an algal oil emulsion. This emulsion was then mixed with a gelling agent and allowed to stand at room temperature for 18 hours to obtain the algal oil emulsion gel. The gelling agent comprised sucrose, sodium alginate, and high-methoxyl pectin. D -gluconic acid- δ - Lactones and water, sucrose account for 60%~70% w / w of the algal oil emulsion gel, and the total of sodium alginate and high-methoxyl pectin accounts for 2%~4% w / w of the algal oil emulsion gel. D -gluconic acid- δ - Lactones account for 1%~2% w / w of algal oil emulsion gels; The modified starch solution contains 2% to 4% w / w octenyl succinate starch ester; the algal oil emulsion is obtained by mixing the modified starch solution and algal oil at a mass ratio of 8 to 10:1 and then dispersing them at high speed; the algal oil emulsion accounts for 5% to 15% w / w of the algal oil emulsion gel.

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