A functional salt of lutein loaded and a preparation method thereof

Abstract

The application discloses a functional salt loaded with lutein and a preparation method thereof, and belongs to the technical field of microcapsules. The functional salt with a hollow structure is prepared by using edible oil containing lutein as an oil phase, using food source protein containing edible salt and a food-grade polysaccharide solution as an aqueous phase, and using a spray drying method. The functional salt loaded with lutein prepared by the method does not contain any surfactant, and can realize a salt reduction effect of 30-50% under the same sufficient salty taste. In addition, the lutein is encapsulated in the oil phase, so that the problems of poor water solubility and low bioavailability of the lutein are solved, and the daily dietary supplement of the lutein is increased.

Description

Technical Field

[0001] This invention belongs to the field of microcapsule technology, and particularly relates to a lutein-loaded functional salt and its preparation method. Background Technology

[0002] The main component of table salt in daily life is sodium chloride (NaCl), which is commonly used to increase the saltiness and improve the flavor of food. High salt (sodium) intake is directly related to the incidence of hypertension, and cardiovascular diseases caused by high salt (sodium) account for 49% of all cardiovascular diseases. Over time, it may also lead to heart failure, kidney disease, stomach cancer, osteoporosis, and other diseases. Many countries and organizations advocate and implement "salt reduction" and "sodium reduction" initiatives in food. In addition, the World Health Organization (WHO) recommends cooperating with the food industry and encouraging the reduction of sodium content in products to the lowest feasible level.

[0003] Cargill has developed a type of hollow flake salt. This flake salt consists of cone-shaped crystals with a hollow structure, a large surface area, and rapid dissolution, quickly producing a strong salty sensation on the tongue in minute quantities. The overall advantage of these products is that they are mostly composed of salt, have no chemical aftertaste, and are labeled "clean." However, their disadvantage is their high production cost, which limits their commercial application. Tate & Lyle's hollow salt microspheres can reduce salt content by 25-50%, producing a stronger salty sensation due to their larger surface area, but lack nutritional functions and other product characteristics. CN114568681 A describes hollow sodium chloride microspheres with small particle size, low bulk density, rapid dissolution rate, good diffusion ability, and a salt reduction effect of 30-50%, suitable for cold dishes and dry-tossed foods. However, this product uses non-food source raw materials in its manufacturing process, which limits its application to some extent. Therefore, under the premise of "reducing salt without reducing saltiness," enabling hollow-structured edible salt to have good powder properties and functional activity is a problem that urgently needs to be solved.

[0004] Lutein is a terpenoid compound belonging to the lutein family. It participates in the synthesis of vitamin A in the body and is also a major pigment in the macular region of the human retina. Studies have shown that ensuring adequate lutein intake is crucial for eye health, as lutein can effectively prevent blue light damage to retinal pigment epithelial cells and prevent diseases such as macular degeneration. However, the human body cannot synthesize lutein itself, and most of the lutein in the body comes from dietary intake. The "Chinese Dietary Reference Intakes (2013)" recommends a specific value of 10 mg / day for lutein. However, according to reports, most Chinese residents obtain only about 3 mg of lutein daily from their diet, and should consume more functional foods rich in lutein to increase their intake. Furthermore, the poor water solubility and low bioavailability of lutein limit its application in food. Therefore, the development of a functional salt that can achieve precise nutrient delivery of lutein while reducing salt intake, thereby improving its bioavailability in the human body, has become a current research focus. Summary of the Invention

[0005] The purpose of this invention is to develop a lutein-loaded functional salt based on an oil-in-water emulsion using spray drying technology. This functional salt has a hollow structure, which can achieve a salt reduction effect and can load lutein, so that it can increase the dietary supplement of lutein while giving food a salty taste.

[0006] To achieve the above objectives, the present invention first provides a method for preparing lutein-loaded functional salts, comprising the following steps:

[0007] (1) Preparation of wall material solution: Weigh food source protein and food grade polysaccharide, dissolve them in water, add edible salt and stir to dissolve, and obtain wall material solution;

[0008] (2) Preparation of core material solution: Under light-protected conditions, lutein was dissolved in edible oil and stirred until completely dissolved to obtain core material solution;

[0009] (3) Preparation of oil-in-water emulsion: The wall material solution from step (1) and the core material solution from step (2) are mixed, dispersed at high speed and homogenized under high pressure to obtain an oil-in-water emulsion;

[0010] (4) Spray drying: Connect the oil-in-water emulsion prepared in step (3) to a spray drying injection pump and perform spray drying to prepare functional salt loaded with lutein.

[0011] In one embodiment of the present invention, the food source protein includes at least one of whey protein isolate, pea protein, gelatin, and sodium caseinate.

[0012] In one embodiment of the present invention, the food-grade polysaccharide includes at least one of gum arabic, carrageenan, maltodextrin, chitosan, β-glucan, xanthan gum, cellulose nanocrystals, konjac gum, and mannose.

[0013] In one embodiment of the present invention, in step (1), the mass ratio of food source protein to food-grade polysaccharide is 3:1 to 1:1.

[0014] In one embodiment of the present invention, in step (1), after dissolving in water, the total mass fraction of food source protein and food-grade polysaccharide is 0.5-2%.

[0015] In one embodiment of the present invention, in step (1), the amount of edible salt added is 20-30 wt% of the mass of the wall material solution.

[0016] In one embodiment of the present invention, in step (2), the edible oil includes at least one of soybean oil, corn oil, rapeseed oil, and peanut oil.

[0017] In one embodiment of the present invention, in step (2), the concentration of lutein in the core material solution is 0.07 to 0.08 mg / mL.

[0018] In one embodiment of the present invention, in step (3), the weight ratio of the core material solution to the wall material solution is (5:95) to (15:85).

[0019] In one embodiment of the present invention, in step (3), the dispersion conditions for high-speed dispersion are 10,000 to 15,000 rpm and the dispersion time is 3 to 10 min. The high-speed dispersion is carried out in a high-speed disperser, the model of which is MICCRAD-4.

[0020] In one embodiment of the present invention, in step (3), the high-pressure homogenization conditions are 200 to 1200 bar, the high-pressure homogenization cycle is 3 to 6 times, and the high-pressure homogenization equipment is GEA.

[0021] In one embodiment of the present invention, in step (4), the oil-in-water emulsion is connected to the feed pump of the spray dryer. The spray drying conditions are: sample inlet temperature 140–200°C, output port temperature 70–100°C, sample injection rate 4–16 ml / min, pump speed 70–100%, air flow meter 20–30 mm, and vacuum degree -50–-100 mbar. The spray drying equipment is a BUCHI B-290.

[0022] The present invention also provides a functional salt loaded with lutein prepared according to the above preparation method.

[0023] In one embodiment of the present invention, the functional salt comprises, by weight percentage, 60-85% edible salt, 2-5% a mixture of food-source protein and food-grade polysaccharide, 15-30% edible oil, and 0-2% water, with the sum of the weight percentages of each raw material being 100%.

[0024] The present invention also provides an application of the above-mentioned lutein-loaded functional salt in the food field.

[0025] In one embodiment of the present invention, the food includes dry-mixed and cold-dressed foods.

[0026] The beneficial effects of this invention are:

[0027] (1) The lutein-loaded functional salt described in this invention does not contain any surfactants.

[0028] (2) The lutein-loaded functional salt described in this invention can achieve a salt reduction effect of 30-50% under the same sufficient saltiness.

[0029] (3) The spray-dried product obtained by the present invention using emulsion as carrier has good free flowability and is not prone to clumping during long-term storage.

[0030] (4) The lutein-loaded functional salt of the present invention encapsulates lutein in the oil phase to solve the problems of poor water solubility and low bioavailability, thereby increasing the daily dietary supplementation of lutein.

[0031] (5) The lutein-loaded functional salt described in this invention does not contain any inorganic compounds other than table salt, including potassium chloride. Therefore, it can be consumed by hypertensive patients after taking antihypertensive drugs, and has a wider market than ordinary low-sodium salt. Attached Figure Description

[0032] Figure 1 SEM images of the samples prepared in Examples 1-3 and Comparative Examples 1-3.

[0033] Figure 2 The Fourier transform infrared spectra of the samples prepared in Examples 1-3 and Comparative Examples 1-3 are shown. The samples numbered 1-9 in the figure correspond to Examples 1, 2, 3, Comparative Examples 1, 2, and 3, respectively, gum arabic, whey protein isolate, and lutein.

[0034] Figure 3 This is a photograph of the powder from Example 1, which was stored at room temperature for 4 months and then freely scattered from a constant height. Detailed Implementation

[0035] The present invention will now be described in detail with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0036] The raw materials used in the embodiments and comparative examples of this invention are as follows: edible salt was purchased from Dalian Salt Chemical Group, whey protein isolate and gum arabic were purchased from Shanghai Yuanye Biotechnology Co., Ltd., soybean oil was purchased from Jinlongyu, and lutein was purchased from Maclean's Reagent Network.

[0037] Example 1

[0038] A method for preparing a functional salt loaded with lutein includes the following steps:

[0039] (1) Preparation of wall material solution: Weigh whey protein isolate and gum arabic at a mass ratio of 1:1, add water at a solute weight percentage of 1wt%, and add edible salt at a mass of 25wt% of the wall material solution and stir to dissolve.

[0040] (2) Preparation of core material solution: Under light-protected conditions, lutein was dissolved in soybean oil and stirred until completely dissolved, so that the concentration of lutein in the solution was 0.075 mg / mL;

[0041] (3) The core material solution in step (2) and the wall material solution in step (1) are mixed at a mass ratio of 10:90 and dispersed into an oil-in-water emulsion using a high-speed disperser. The initial emulsion is then processed into an oil-in-water emulsion with smaller particle size by a high-pressure homogenizer.

[0042] The emulsion was dispersed at 12,000 rpm for 3 minutes; the high-pressure homogenization was performed at 600 bar for 3 cycles.

[0043] (4) Connect the oil-in-water emulsion from step (3) to the spray drying injection pump and perform spray drying.

[0044] In step (2), the drying conditions are: injection port temperature 160℃, output port temperature 90℃, injection rate 8ml / min, pump speed 90%, air flow meter 25mm, and vacuum degree -80mbar.

[0045] After collection, the powdered product should be stored in a cool, dry place.

[0046] Example 2: The difference between Example 2 and Example 1 is that the mass ratio of whey protein isolate to gum arabic is 3:1.

[0047] Example 3: The difference between Example 3 and Example 1 is that the mass ratio of the core material solution in step (2) to the wall material solution in step (1) is 5:95.

[0048] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that gum arabic was not added.

[0049] Comparative Example 2: The difference between Example 2 and Example 1 is that the mass ratio of whey protein isolate to gum arabic is 1:3.

[0050] Comparative Example 3: The difference between Example 2 and Example 1 is that the mass ratio of the core material solution in step (2) to the wall material solution in step (1) is 20:80.

[0051] The salts obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, and the test results are as follows:

[0052] Figure 1 SEM images of the samples prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1. The particle size test results of ordinary table salt and Examples 1-3 and Comparative Examples 1-3 are also shown in Table 1. Figure 1 As shown in Table 1, compared with ordinary table salt, the particle size of Examples 1-3 decreased from 350 μm to below 10 μm, and a hollow structure was formed. In Example 3, square particles and hollow spherical particles coexisted, possibly because the gaps between the water-in-oil emulsion particles were too large when the oil phase was reduced to 5% wt, leading to direct crystallization during spray drying. Comparative Examples 1-3 showed obvious fusion phenomena, with Comparative Example 2 exhibiting the most severe particle fusion, and its particle size could not be accurately measured.

[0053] Table 1

[0054] example Particle size (μm) ordinary table salt 350.8±74.99 Example 1 3.89±1.26 Example 2 7.69±1.84 Example 3 6.58±1.52 Comparative Example 1 6.88±2.84 Comparative Example 3 13.69±3.34

[0055] Table 2 shows the solubility test results of the samples prepared in Examples 1-3 and Comparative Examples 1-3. As can be seen from Table 2, the solubilities of Examples 1-3 are 5.70±0.05, 5.84±0.62, and 7.09±0.33 g / mL, respectively, while the solubility of ordinary table salt is 4.25±0.68 g / mL. The functional salts in Examples 1-3 have a solubility 34.1-66.8% higher than that of ordinary table salt. The percentage increase in solubility of Comparative Examples 2 and 3 compared to ordinary table salt is very small, only 14.1% and 15.8%, respectively. The higher solubility of Comparative Example 1 may be related to the solubility of whey protein isolate; the higher the weight percentage of whey protein isolate, the greater the solubility.

[0056] Table 2

[0057] example Solubility (g / 100mL) ordinary table salt 4.25±0.68 Example 1 5.70±0.05 Example 2 5.84±0.62 Example 3 7.09±0.33 Comparative Example 1 6.30±0.35 Comparative Example 2 4.92±0.13 Comparative Example 3 4.85±0.84

[0058] Table 3 shows the test data of moisture content and water activity of the samples prepared in Examples 1-3 and Comparative Examples 1-3. The results show that the moisture content of Examples 1-3 is 3.07±1.81, 4.29±0.64, and 3.63±0.60 g / 100g, respectively, while the moisture content of ordinary table salt is 1.30±0.25 g / 100g. The functional salts in Examples 1-3 have a moisture content 1.36-2.3 times higher than that of ordinary table salt. The water activities of Examples 1-3 are 0.34±0.035, 0.34±0.036, and 0.33±0.021, respectively, while the water activity of ordinary table salt is 0.71±0.003. The functional salts in Examples 1-3 have a water activity 52.1-53.5% lower than that of ordinary table salt.

[0059] Table 3

[0060]

[0061]

[0062] Table 4 shows the sensory evaluation and salinity test results of the samples prepared in Examples 1-3 and Comparative Examples 1-3. It can be seen that the saltiness of Examples 1-3 is relatively high and there is no significant difference from ordinary table salt. The salinity is reduced by 48.4%, 37.1% and 26.3% respectively, and the sensory acceptance is relatively high. Under the same saltiness, the salt intake reduction effect can reach 26-48%.

[0063] Table 4

[0064] example Saltiness rating Salinity value (mg / 100g) ordinary table salt 10 416.00±0.02 Example 1 9.6±0.5 214.79±9.58 Example 2 9.4±0.5 261.52±6.31 Example 3 9.8±0.4 306.62±9.05 Comparative Example 1 9.2±0.4 261.74±2.47 Comparative Example 2 8.6±0.5 261.74±3.11 Comparative Example 3 8±0.7 192.54±3.48

[0065] Figure 2 The Fourier transform infrared spectra of the samples prepared in Examples 1-3 and Comparative Examples 1-3 show that whey protein isolate has a wavelength of 1655 cm⁻¹. -1 and 1533cm -1 There is a characteristic peak at 1657cm. -1 The point is the tensile vibration of amide I with C=O, 1533 cm. -1 The CN tensile and NH bending vibrations of the amide II band are observed at 3427 cm⁻¹. Gum arabic at 3427 cm⁻¹ -1 There is a strong absorption band at 1614 cm⁻¹, which may be due to the presence of hydroxyl groups; -1 and 1423cm -1 There are two strong absorption bands at this point, which are for carboxylates COO. - The asymmetric and symmetric stretching. In the infrared spectra of Examples 1-3, the characteristic peak intensity of lutein decreased, indicating successful encapsulation of lutein.

[0066] The total oil content of the spray-dried powder was determined by hexane extraction. 1 g of the spray-dried powder was weighed and added to 5 ml of water, then shaken at 450 rpm for 10 min. 15 ml of hexane was then added and mixed thoroughly, followed by centrifugation at 4400 g for 10 min. The supernatant was collected. The residue at the bottom was washed with hexane and the above centrifugation procedure was repeated twice. The supernatant was collected and rotary evaporated at 50 °C to constant weight.

[0067] Weigh 1g of the spray-dried powder and add 15ml of hexane. Stir at 150rpm for 2min, then filter through filter paper. Wash the residue three times with 20ml of hexane. Collect the filtrate and rotary evaporate at 50℃ to constant weight.

[0068] Oil encapsulation rate (EE,%)=(TO-SO) / TO×100 (1) Where TO is the total oil content of the powder after spray drying, and SO is the oil content on the surface of the powder particles after spray drying.

[0069] Table 5 shows the surface oil content, total oil content, and calculated oil encapsulation efficiency of the sample particles prepared in Examples 1-3 and Comparative Examples 1-3. It can be seen that the oil encapsulation efficiencies of Examples 1-3 are 87.29±2.39, 83.33±1.62, and 82.85±0.04%, respectively, significantly higher than the oil encapsulation efficiencies of Comparative Examples 1-3 (73.39±1.52, 58.08±3.10, and 71.96±2.44%), representing an increase of 12.89-50.29%. Higher encapsulation efficiency indicates stronger protection for the oil phase and lutein. Furthermore, Figure 3 The results show that Example 1 maintained good free flowability and showed no obvious clumping after being stored at room temperature for 4 months. This product was prepared using an emulsion as a carrier, and the addition of the oil phase may have reduced the interaction between particles, thus playing a certain role in preventing clumping.

[0070] Table 5

[0071] example Surface oil content (g / g powder) Total oil content (g / g powder) Oil encapsulation rate (%) Example 1 0.023±0.003 0.181±0.01 87.29±2.39 Example 2 0.031±0.004 0.186±0.006 83.33±1.62 Example 3 0.015±0.004 0.091±0.003 82.85±0.04 Comparative Example 1 0.056±0.001 0.210±0.01 73.39±1.52 Comparative Example 2 0.077±0.011 0.184±0.013 58.08±3.10 Comparative Example 3 0.054±0.003 0.193±0.008 71.96±2.44

[0072] The lutein encapsulation efficiency of the spray-dried powder was determined using organic solvent extraction. 1 ml of the oil-in-water emulsion was added to 5 ml of methanol-dichloromethane (2:1, v / v), shaken thoroughly to dissolve, centrifuged, and the supernatant was measured for absorbance. Similarly, 0.1 g of the powder was dissolved in 1 ml of methanol-dichloromethane (2:1, v / v) solution, centrifuged, and the supernatant was measured for absorbance. This process was repeated three times, and the average value was taken.

[0073] Lutein encapsulation efficiency (%) = C2 / C1 × EE × 100

[0074] C1 represents the lutein concentration in the emulsion calculated from the standard curve, C2 represents the lutein concentration in the spray-dried powder calculated from the standard curve, and EE represents the oil encapsulation rate.

[0075] Determination of the standard curve of lutein

[0076] Add 1 mg of lutein standard to an EP tube, and dilute to volume with a 2:1 mixture of methanol and dichloromethane. Prepare standard solutions with concentrations of 0.125, 0.25, 0.5, 1, and 2 mg / mL. Measure the absorbance using a spectrophotometer, taking the average of three parallel measurements. The maximum absorption wavelength of lutein standard in methanol and dichloromethane is 445 nm. The concentration of lutein is positively correlated with the absorbance of the solution; therefore, the absorbance can be measured using a UV spectrophotometer to determine the lutein content in the sample. The linear equation of the lutein standard curve is as follows:

[0077] Y = 0.3885X + 0.0127, R 2 =0.997

[0078] The concentrations of lutein in the oil-in-water emulsions and spray-dried powders prepared in Examples 1-3 and Comparative Examples 1-3, calculated using regression equations, and the final calculated lutein encapsulation rates are listed in Table 6. The results show that the lutein encapsulation rates in Examples 1-3 were 66.20±2.03, 61.73±1.20, and 63.98±3.47%, respectively, significantly higher than those in Comparative Examples 1-3. This indicates that lutein is somewhat lost during spray drying, while Examples 1-3 exhibit a higher oil phase encapsulation rate, providing some protection during the spray drying process.

[0079] Table 6

[0080]

[0081] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing a lutein-loaded functional salt, characterized in that, Includes the following steps: (1) Preparation of wall material solution: Weigh food source protein and food grade polysaccharide, dissolve them in water, add edible salt and stir to dissolve to obtain wall material solution. The food source protein is whey protein isolate, the food grade polysaccharide is gum arabic, the mass ratio of whey protein isolate to gum arabic is 1~3:1, and the amount of edible salt added is 20~30% of the mass of wall material solution; (2) Preparation of core material solution: Under light-protected conditions, lutein was dissolved in edible oil and stirred until completely dissolved to obtain core material solution; (3) Preparation of oil-in-water emulsion: The wall material solution from step (1) and the core material solution from step (2) are mixed, dispersed at high speed and homogenized under high pressure to obtain an oil-in-water emulsion. The weight ratio of the core material solution to the wall material solution is (10:90) to (15:75). (4) Spray drying: Connect the oil-in-water emulsion prepared in step (3) to the spray drying injection pump and spray dry to prepare the functional salt loaded with lutein.

2. The preparation method according to claim 1, characterized in that, In step (1), after dissolving in water, the total mass fraction of food source protein and food-grade polysaccharide is 0.5-2%.

3. The preparation method according to claim 1, characterized in that, In step (2), the edible oil includes at least one of soybean oil, corn oil, rapeseed oil, and peanut oil, and the concentration of lutein in the core material solution is 0.07 to 0.08 mg / mL.

4. The preparation method according to claim 1, characterized in that, In step (3), the dispersion conditions for high-speed dispersion are 10,000 to 15,000 rpm, dispersion time is 3 to 10 min, high-pressure homogenization conditions are 200 to 1200 bar, and high-pressure homogenization cycles are 3 to 6 times.

5. The preparation method according to claim 1, characterized in that, In step (4), the oil-in-water emulsion is connected to the feed pump of the spray dryer. The spray drying conditions are: sample inlet temperature 140-200 ℃, output port temperature 70-100 ℃, sample injection rate 4-16 ml / min, pump speed 70-100%, air flow meter 20-30 mm, and vacuum degree -50--100 mbar.

6. The lutein-loaded functional salt prepared by the preparation method according to any one of claims 1 to 5.

7. The functional salt according to claim 6, characterized in that, The functional salt comprises, by weight percentage, 60-85% edible salt, 2-5% a mixture of food-source protein and food-grade polysaccharides, 15-30% edible oil, and 0-2% water, with the sum of the weight percentages of each ingredient being 100%.

8. Use of the lutein-loaded functional salt according to claim 6 or 7 in the food field.

9. The use according to claim 8, characterized in that, The food items include dry-fried and cold-dressed foods.

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