Long-shelf-life algae oil drinking type normal-temperature yoghourt and preparation method thereof

Abstract

The invention discloses long-shelf-life algae oil drinking type normal-temperature yoghourt and a preparation method thereof. The preparation method comprises the following steps: adding ingredients such as fresh milk, algal oil and a compound emulsifying thickener, fermenting, emulsifying, shearing and homogenizing, sterilizing at ultra-high temperature, sterile filling and the like, so as to prepare the long-shelf-life drinking type normal-temperature algal oil yoghourt. Through reasonable formula design and process optimization design, the dispersion application operability of algal oil is optimized, and the problems of floating oil, elutriation, precipitation and the like of a final product system caused by the fact that protein and fat in a low-viscosity normal-temperature yoghourt system are easily denatured, separated, coagulated and the like after being heated and subjected to high temperature and high pressure are solved; and the feasibility of production equipment is optimized. The product has the characteristic of natural algae green appearance and fresh and pleasant taste, is rich in high-quality milk protein, milk fat, EPA, vitamins and the like, and is richer and more balanced in nutrition.

Description

Technical Field

[0001] The invention belongs to the technical field of yogurt preparation, and particularly relates to a long-shelf-life algae oil drinkable room-temperature yogurt and a preparation method thereof. Background Art

[0002] Nannochloropsis spp. is a microalgae rich in EPA (eicosapentaenoic acid), which was approved by the National Health Commission as a new food ingredient in 2021. EPA is a type of Omega-3 and is essential for human health, especially human growth and development. A large number of studies have shown that EPA can promote the circulation of fat in the blood, reduce low-density lipoprotein cholesterol and triglyceride levels, increase high-density lipoprotein cholesterol levels, regulate platelets, effectively prevent cardiovascular diseases, and protect cardiovascular health. It is known as the "blood scavenger."

[0003] Due to the high unsaturation of EPA in algae oil, algae oil is easily oxidized and degraded after high temperature heating. If it is added without treatment, it will cause the product to become rancid, have an odor, have oil esters float up, and have uneven color. In addition, the oxidative degradation of EPA will also cause it to lose its original nutritional and health value.

[0004] Drinkable room temperature yogurt refers to a yogurt with a viscosity of less than 100cP, and its shelf life at room temperature is usually 100-180 days. For areas or remote areas that do not have a complete logistics cold chain, a sufficiently long shelf life is needed, and it is particularly important to ensure the taste, nutritional quality and system stability of room temperature yogurt during the shelf life. Since room temperature yogurt has poor protein stability at low viscosity, the national invention patent application CN202311712942 discloses a method for preparing a room temperature refreshing flavored yogurt and its application, with a viscosity of 21 to 28mPa·s, which is considered to break the inherent perception of consumers that room temperature yogurt is sticky and sticky, and is a room temperature yogurt with a new texture.

[0005] Since the launch of ambient temperature yogurt, it has rapidly grown into a 50 billion yuan category. Since 2024, due to the improvement of consumers' health awareness, it is imperative to strengthen the intensity and frequency of product innovation. Summary of the invention

[0006] The primary purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a method for preparing algae oil drinkable room temperature yogurt with a long shelf life.

[0007] Another object of the present invention is to provide long-shelf-life algae oil drinkable room-temperature yogurt prepared by the preparation method.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing long-shelf-life algae oil drinkable room-temperature yogurt comprises the following steps:

[0010] (1) heating milk to obtain milk liquid;

[0011] (2) heating the algae oil and the vegetable oil to obtain a mixed liquid;

[0012] (3) adding the mixed solution prepared in step (2), sugar, a compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing them uniformly;

[0013] (4) homogenizing the liquid obtained in step (3);

[0014] (5) sterilizing the liquid prepared in step (4);

[0015] (6) cooling the liquid obtained in step (5);

[0016] (7) adding the liquid prepared in step (6) to a fermentation agent for fermentation;

[0017] (8) stopping the fermentation of the yogurt prepared in step (7) and stirring it evenly;

[0018] (9) homogenizing the yogurt prepared in step (8);

[0019] (10) sterilizing the yogurt obtained in step (9);

[0020] (11) cooling the yogurt obtained in step (10);

[0021] (12) filling the yogurt prepared in step (11) to prepare long-shelf-life algae oil drinkable room temperature yogurt;

[0022] The dosage of each component is as follows by mass percentage: fresh milk 80% to 82%, sugar 6% to 8%, milk protein 0.5% to 1.0%, compound emulsifying thickener 1.5% to 2.0%, algae oil 0.035% to 0.1%, vegetable oil 0.07% to 0.2%, leavening agent 0.0003% to 0.0006%, and water as the balance;

[0023] The composition of the compound emulsifying thickener is as follows: hydroxypropyl distarch phosphate, pectin and mono- and di-glycerol fatty acid esters are mixed in a mass ratio of (43.3-53.4): (40-43.3): (6.6-13.4).

[0024] The milk is preferably fresh milk.

[0025] The sugar is preferably syrup, and its solid content is preferably 70-80% by mass; more preferably 75% by mass.

[0026] The syrup is preferably at least one of fructose syrup, maltose syrup and corn syrup.

[0027] The milk protein is preferably concentrated milk protein; more preferably concentrated milk protein with a protein content of 80-90% w / w; most preferably concentrated milk protein with a protein content of 85% w / w.

[0028] The algae oil is preferably pseudo-Nanococcus oil.

[0029] The vegetable oil is preferably at least one of soybean oil, corn oil and sunflower oil.

[0030] The addition ratio of the algae oil to the vegetable oil is preferably 1:2 by mass.

[0031] The fermentation agent is lactic acid bacteria; preferably Streptococcus salivarius thermophilus subspecies and Lactobacillus delbrueckii subspecies bulgaricus.

[0032] The heating temperature in step (1) is preferably 53-58°C.

[0033] The heating time in step (2) is preferably 5 to 7 minutes.

[0034] The shearing speed in step (3) is preferably 2500 to 3500 r / min, and more preferably 3000 r / min.

[0035] The shearing time in step (3) is preferably 10 to 15 minutes.

[0036] The shearing temperature in step (3) is preferably 50-55°C.

[0037] The homogenization temperature in step (4) is preferably 50-55°C.

[0038] The homogenization pressure in step (4) is preferably 18-22 MPa; more preferably 20 MPa.

[0039] The sterilization temperature in step (5) is preferably 90-100°C; more preferably 95°C.

[0040] The sterilization time in step (5) is preferably 5 minutes.

[0041] The cooling temperature in step (6) is preferably below 50°C; more preferably 43°C.

[0042] The fermentation temperature in step (7) is preferably 40-45°C; preferably 43°C.

[0043] The fermentation time in step (7) is preferably 6 to 8 hours.

[0044] The pH for stopping the fermentation in step (8) is preferably 4.3 to 4.4.

[0045] The stirring speed in step (8) is preferably 600 to 1000 r / min, and more preferably 800 r / min.

[0046] The homogenization pressure in step (9) is preferably 18-22 MPa, and more preferably 20 MPa.

[0047] The sterilization method described in step (10) is preferably ultra-high temperature sterilization.

[0048] The ultra-high temperature sterilization conditions are preferably 121° C., 3 to 5 seconds; more preferably 121° C., 4 seconds.

[0049] The cooling temperature in step (11) is preferably below 30°C; more preferably 25°C.

[0050] The filling conditions described in step (12) are preferably aseptic filling.

[0051] A long-shelf-life algae oil drinkable room-temperature yogurt is obtained by the preparation method.

[0052] The long-shelf-life algae oil drinkable room-temperature yogurt can be stored at room temperature for 12 months, has a protein content of ≥2.4g / 100g, a fat content of ≥2.8g / 100g, and a sugar content of 6-8%.

[0053] Compared with the existing technology, the present invention has the following advantages and beneficial effects:

[0054] (1) The present invention solves the following technical problems through reasonable formula design and process optimization design: the application operation method of algae oil in water-in-oil system is optimized through vegetable oil embedding and dispersion; the color protection and antioxidant effect of algae oil are effectively achieved by combining the material preparation, homogenization process and ultra-high temperature instantaneous sterilization process below 55°C; the system problem that protein and milk fat are prone to precipitation, stratification and flocculation after high temperature and high pressure heating processing is solved by combining the adjustment of compound emulsifier thickener and fermentation agent; the product's optimal nutritional value and best sensory experience are retained through ultra-high temperature instantaneous sterilization process, while the product shelf life is greatly extended.

[0055] (2) The present invention screened emulsifiers, optimized single emulsifiers and compound emulsifiers, and finally obtained a reasonable combination of the various components of the compound emulsifier stabilizer, thereby achieving the stability of color, flavor and state of algae oil in water-in-oil long-life room temperature yogurt products; greatly reducing the oil-water interfacial tension in algae oil room temperature yogurt products, playing an effective role in stabilizing emulsion droplets; the product viscosity is 8-9cP, the liquid fluidity is good, and it will not cause the problem of tube sticking that often occurs during ultra-high temperature sterilization of high-protein and high-fat products, and the product has a refreshing, delicate and silky taste.

[0056] (3) The product has a natural algae green appearance and is rich in EPA, vitamins, minerals, amino acids, etc. It ensures people's nutrition and health through scientific means and creates favorable conditions for market promotion and circulation.

[0057] (4) The drinkable room temperature yogurt prepared with the pseudo-Nanococcus algae oil of the present invention is a one-ingredient product with a simple production process and easy operation. It can be produced on the original production line of jelly, beverage, and dairy product manufacturers after slight adjustments.

[0058] The physical and chemical indicators of the final product are:

[0059] Protein ≥2.4 g / 100 g

[0060] Fat ≥ 2.6 g / 100 g

[0061] Shelf life is 12 months.

[0062] The algae oil raw material is a paste, which is difficult to disperse, and it is difficult to stabilize in the water-in-oil system after dispersion. The present invention improves the thermal instability of algae oil and the stability problem in the refreshing water-in-oil system by rationally screening the ratio of various components and process optimization technology, greatly reduces the product viscosity, and develops a nutritious and delicious long-lasting microspherical algae oil drinkable room temperature yogurt with a shelf life of 12 months, which has broad market prospects. DETAILED DESCRIPTION

[0063] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0064] Example 1

[0065] The ingredients and mass percentages of the long-lasting Nannochloropsis algae oil drinkable room temperature yogurt are as follows: 80% fresh milk, 6% fructose syrup (solids 75%, the same below), 0.5% milk protein (concentrated milk protein with 85% protein content, the same below), 1.5% compound emulsifying thickener (the compound emulsifying thickener is composed of the following components in the following mass ratio: hydroxypropyl distarch phosphate: pectin: mono- and di-glycerol fatty acid esters = 53.4:40:6.6), 0.035% Nannochloropsis algae oil, 0.07% vegetable oil (soybean oil, the same below), 0.0003% starter (French Pulse YO-PROX BA501, the same below), and the balance is water;

[0066] (1) heating milk to 53° C. to obtain milk liquid;

[0067] (2) heating the algae oil and the vegetable oil for 5 minutes to prepare a mixed solution;

[0068] (3) adding the liquid prepared in step (2), sugar, compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing at 50° C. and 3000 r / min for 10 min until the liquid is uniform;

[0069] (4) homogenizing the liquid prepared in step (3) at 50° C. and 20 MPa;

[0070] (5) sterilizing the liquid obtained in step (4) at 95° C. for 5 min;

[0071] (6) cooling the liquid obtained in step (5) to 43° C.;

[0072] (7) adding the liquid prepared in step (6) to the fermentation agent and fermenting at 43° C. for 8 h;

[0073] (8) stopping the fermentation of the yogurt with a pH of 4.4 obtained in step (7) and stirring at 800 r / min;

[0074] (9) homogenizing the yogurt prepared in step (8) at 20 MPa;

[0075] (10) sterilizing the yogurt prepared in step (9) at 121° C. for 4 seconds;

[0076] (11) cooling the yogurt prepared in step (10) to 25° C.;

[0077] (12) The yogurt prepared in step (11) is aseptically filled to prepare a long-lasting drinkable yogurt containing Pseudomonas aeruginosa oil at room temperature.

[0078] Example 2

[0079] The ingredients and mass percentage of the long-term drinking room-temperature yogurt containing pseudo-Nanococcus algae oil are as follows: 82% fresh milk, 8% fructose syrup, 1.0% milk protein, 2.0% compound emulsifying thickener (the compound emulsifying thickener is composed of the following components in the following mass ratio: hydroxypropyl distarch phosphate: pectin: mono- and di-glycerol fatty acid esters = 43.3: 43.3: 13.4), 0.1% pseudo-Nanococcus algae oil, 0.2% vegetable oil, 0.0006% starter, and the balance is water;

[0080] (1) heating milk to 53° C. to obtain milk liquid;

[0081] (2) heating the algae oil and the vegetable oil for 5 minutes to prepare a mixed solution;

[0082] (3) adding the liquid prepared in step (2), sugar, compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing at 50° C. and 3000 r / min for 10 min until the liquid is uniform;

[0083] (4) homogenizing the liquid prepared in step (3) at 50° C. and 20 MPa;

[0084] (5) sterilizing the liquid obtained in step (4) at 95° C. for 5 min;

[0085] (6) cooling the liquid obtained in step (5) to 43° C.;

[0086] (7) adding the liquid prepared in step (6) to the fermentation agent and fermenting at 43° C. for 6 h;

[0087] (8) stopping the fermentation of the yogurt with a pH of 4.4 obtained in step (7) and stirring at 800 r / min;

[0088] (9) homogenizing the yogurt prepared in step (8) at 20 MPa;

[0089] (10) sterilizing the yogurt prepared in step (9) at 121° C. for 4 seconds;

[0090] (11) cooling the yogurt prepared in step (10) to 25° C.;

[0091] (12) The yogurt prepared in step (11) is aseptically filled to prepare a long-lasting drinkable yogurt containing Pseudomonas aeruginosa oil at room temperature.

[0092] Example 3

[0093] The ingredients and mass percentage of the long-term drinking room-temperature yogurt containing pseudo-Nanococcus algae oil are as follows: 80% fresh milk, 6% fructose syrup, 0.5% milk protein, 1.5% compound emulsifying thickener (the compound emulsifying thickener is composed of the following components in the following mass ratio: hydroxypropyl distarch phosphate: pectin: mono- and di-glycerol fatty acid esters = 53.4:40:6.6), 0.035% pseudo-Nanococcus algae oil, 0.07% vegetable oil, 0.0003% starter, and the balance is water;

[0094] (1) heating milk to 58° C. to obtain milk liquid;

[0095] (2) heating the algae oil and the vegetable oil for 7 minutes to prepare a mixed solution;

[0096] (3) adding the liquid prepared in step (2), sugar, compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing at 50° C. and 3500 r / min for 15 min until the liquid is uniform;

[0097] (4) homogenizing the liquid prepared in step (3) at 50° C. and 20 MPa;

[0098] (5) sterilizing the liquid obtained in step (4) at 95° C. for 5 min;

[0099] (6) cooling the liquid obtained in step (5) to 43° C.;

[0100] (7) adding the liquid prepared in step (6) to the fermentation agent and fermenting at 43° C. for 6 h;

[0101] (8) stopping the fermentation of the yogurt with a pH of 4.4 obtained in step (7) and stirring at 800 r / min;

[0102] (9) homogenizing the yogurt prepared in step (8) at 20 MPa;

[0103] (10) sterilizing the yogurt prepared in step (9) at 121° C. for 4 seconds;

[0104] (11) cooling the yogurt prepared in step (10) to 25° C.;

[0105] (12) The yogurt prepared in step (11) is aseptically filled to prepare a long-lasting drinkable yogurt containing Pseudomonas aeruginosa oil at room temperature.

[0106] Comparative Example 1

[0107] The ingredients and mass percentage of the long-term drinking room temperature yogurt containing pseudo-Nanococcus algae oil are as follows: 80% fresh milk, 6% fructose syrup, 0.5% milk protein, 1.5% compound emulsifying thickener (the compound emulsifying thickener is composed of the following components in the following mass ratio: hydroxypropyl distarch phosphate: pectin: mono- and di-glycerol fatty acid esters = 53.4:40:6.6), 0.13% pseudo-Nanococcus algae oil, 0.26% vegetable oil, 0.0003% starter, and the balance is water;

[0108] (1) heating milk to 53° C. to obtain milk liquid;

[0109] (2) heating the algae oil and the vegetable oil for 5 minutes to prepare a mixed solution;

[0110] (3) adding the liquid prepared in step (2), sugar, compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing at 50° C. and 3000 r / min for 10 min until the liquid is uniform;

[0111] (4) homogenizing the liquid prepared in step (3) at 50° C. and 20 MPa;

[0112] (5) sterilizing the liquid obtained in step (4) at 95° C. for 5 min;

[0113] (6) cooling the liquid obtained in step (5) to 43° C.;

[0114] (7) adding the liquid prepared in step (6) to the fermentation agent and fermenting at 43° C. for 8 h;

[0115] (8) stopping the fermentation of the yogurt with a pH of 4.4 obtained in step (7) and stirring at 800 r / min;

[0116] (9) homogenizing the yogurt prepared in step (8) at 20 MPa;

[0117] (10) sterilizing the yogurt prepared in step (9) at 121° C. for 4 seconds;

[0118] (11) cooling the yogurt prepared in step (10) to 25° C.;

[0119] (12) The yogurt prepared in step (11) is aseptically filled to prepare a long-lasting drinkable yogurt containing Pseudomonas aeruginosa oil at room temperature.

[0120] Comparative Example 2

[0121] The ingredients and mass percentage of the long-term drinking room-temperature yogurt containing pseudo-Nanococcus algae oil are as follows: 80% fresh milk, 6% fructose syrup, 0.5% milk protein, 1.5% compound emulsifying thickener (the compound emulsifying thickener is composed of the following components in the following mass ratio: hydroxypropyl distarch phosphate: soluble soybean polysaccharide: mono- and di-glycerol fatty acid esters = 53.4:40:6.6), 0.035% pseudo-Nanococcus algae oil, 0.07% vegetable oil, 0.0003% starter, and the balance is water;

[0122] (1) heating milk to 53° C. to obtain milk liquid;

[0123] (2) heating the algae oil and the vegetable oil for 5 minutes to prepare a mixed solution;

[0124] (3) adding the liquid prepared in step (2), sugar, compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing at 50° C. and 3000 r / min for 10 min until the liquid is uniform;

[0125] (4) homogenizing the liquid prepared in step (3) at 50° C. and 20 MPa;

[0126] (5) sterilizing the liquid obtained in step (4) at 95° C. for 5 min;

[0127] (6) cooling the liquid obtained in step (5) to 43° C.;

[0128] (7) adding the liquid prepared in step (6) to the fermentation agent and fermenting at 43° C. for 8 h;

[0129] (8) stopping the fermentation of the yogurt with a pH of 4.4 obtained in step (7) and stirring at 800 r / min;

[0130] (9) homogenizing the yogurt prepared in step (8) at 20 MPa;

[0131] (10) sterilizing the yogurt prepared in step (9) at 121° C. for 4 seconds;

[0132] (11) cooling the yogurt prepared in step (10) to 25° C.;

[0133] (12) The yogurt prepared in step (11) is aseptically filled to prepare drinkable room-temperature yogurt containing Pseudomonas aeruginosa oil.

[0134] Comparative Example 3

[0135] The ingredients and mass percentage of the long-term drinking room-temperature yogurt containing pseudo-Nanococcus algae oil are as follows: 80% fresh milk, 6% fructose syrup, 0.5% milk protein, 1.5% compound emulsifying thickener (the compound emulsifying thickener is composed of the following components in the following mass ratio: hydroxypropyl distarch phosphate: pectin: mono- and di-glycerol fatty acid esters = 53.4:40:6.6), 0.035% pseudo-Nanococcus algae oil, 0.07% vegetable oil, 0.0003% starter, and the balance is water;

[0136] (1) heating milk to 65° C. to obtain milk liquid;

[0137] (2) heating the algae oil and the vegetable oil for 5 minutes to prepare a mixed solution;

[0138] (3) adding the liquid prepared in step (2), sugar, compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing at 50° C. and 3000 r / min for 10 min until the liquid is uniform;

[0139] (4) homogenizing the liquid prepared in step (3) at 50° C. and 20 MPa;

[0140] (5) sterilizing the liquid obtained in step (4) at 95° C. for 5 min;

[0141] (6) cooling the liquid obtained in step (5) to 43° C.;

[0142] (7) adding the liquid prepared in step (6) to the fermentation agent and fermenting at 43° C. for 8 h;

[0143] (8) stopping the fermentation of the yogurt with a pH of 4.4 obtained in step (7) and stirring at 800 r / min;

[0144] (9) homogenizing the yogurt prepared in step (8) at 20 MPa;

[0145] (10) sterilizing the yogurt prepared in step (9) at 80° C. for 30 seconds;

[0146] (11) cooling the yogurt prepared in step (10) to 25° C.;

[0147] (12) The yogurt prepared in step (11) is aseptically filled to prepare drinkable room-temperature yogurt containing Pseudomonas aeruginosa oil.

[0148] Effect Example

[0149] The performance of the Nannochloropsis oil drinkable room temperature yogurt prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was measured.

[0150] 1. Determination of viscosity

[0151] The determination method can be found in the literature (Yang Yuhong, Zhou Xuesong, Ma Qiaokang, Zhong Xiujuan. Effect of process conditions on the stability of sterilized brown lactic acid bacteria milk beverage [J]. China Dairy Industry, 2015, 43(9): 54-56) "1.2.2 Determination of viscosity", that is, 24 hours after sample preparation, the water bath was kept at a constant temperature of 25°C, and the measurement was carried out using a BROOKFIELD viscometer, using a No. 0 rotor, 60 rpm, repeated 3 times, and the average value was taken as the result.

[0152] 2. Determination of precipitation rate

[0153] The determination method is as in "1.3 Stability Determination" of the literature (Si Weili, Zhou Xuesong, Zeng Jianxin. Research on the Stability of Blended Soybean Milk Beverage [J]. Food Industry Science and Technology, 2008, 33 (1): 40-43), that is, accurately weigh 10g of the product and inject it into a centrifuge tube, centrifuge at 3000r / min for 10min, discard the upper solution, accurately weigh the mass of the precipitate, repeat 3 times, and take the average value as the result. Calculate the precipitation rate using the following formula.

[0154]

[0155] 3. Sensory evaluation

[0156] The long-shelf-life algae oil drinkable room-temperature yogurts prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were stored at room temperature, and tasted and their colors were observed.

[0157] 4. The measurement and evaluation results are shown in Table 1 and Table 2:

[0158] The results of Table 1 and Table 2 show that the drinking room temperature yogurt with pseudo-Nanococcus algae oil prepared in Examples 1 to 3 and Comparative Examples 1 and 3 all have the algae green color unique to algae oil, and the color difference is partially caused by the differences in formula and process; its 24h viscosity is 8.2-9.2cP, the precipitation rate is between 1.7% and 2.2%, and the mouthfeel is refreshing; the 12-month viscosity is 7.2-8.6cP, and the Examples 1 to 3 have basically changed little, while the viscosity of Comparative Example 3 after 12 months has changed significantly; the overall sensory evaluation of Examples 1 to 3 is better than that of Comparative Examples 1 and 3, especially the coordination of the algae oil flavor and the yogurt flavor, the former is better; in Examples 1 to 3 and Comparative Example 3, there is basically no phenomenon of fat floating, water precipitation and precipitation in the samples during the 30-day observation period.

[0159] Comparing Example 1 and Comparative Example 1, the difference between the two is that the amount of algae oil added is different, and the amount of algae oil used in Comparative Example 1 is higher than the preferred range. The viscosity and eccentricity of the two are not much different; the taste found that the algae oil in Comparative Example 1 has a heavy smell and the flavor is not harmonious; the stability change range of Example 1 is basically stable during the 6-month and 12-month observation period; while Comparative Example 1 has slight precipitation in 30 days of observation, 1mm green fat floating and slight precipitation in the 6-month observation period, and 2mm of micro-green fat floating in 12 months. The stability of the product fat changes greatly during the 12-month observation period, so excessive addition of algae oil will have a negative impact on the system stability and sensory quality of the product.

[0160] Comparing Example 1 and Comparative Example 2, the difference between the two is that the compound emulsifying thickeners used in the two are different, and the compound emulsifying thickener used in Comparative Example 2 is not within the preferred range. After sterilization and cooling, Comparative Example 2 was placed for 24 hours and severe fat floating, stratification and precipitation occurred, and effective viscosity and centrifugation data could not be measured. The 30-day observation results were basically consistent with the results after 24 hours. Analysis shows that the compound emulsifying thickener is not within the preferred range and cannot prepare a room temperature yogurt product with good stability of Pseudomonas aeruginosa oil.

[0161] Comparing Example 1 and Comparative Example 3, the difference between the two is the different sterilization conditions. Comparative Example 3 found that the stability problem was significantly aggravated during the 6-month observation period, and there was 6mm green fat floating, 8mm water precipitation, and 5mm precipitation during the 12-month observation period. Therefore, the sterilization conditions of 121°C and 4s instantaneous ultra-high temperature sterilization are more guaranteed for the system stability and sensory quality of the 6-12 month shelf life of the Nannochloropsis oil drinkable room temperature yogurt product.

[0162] Table 1 Performance measurement results of Examples 1 to 3

[0163]

[0164] Table 2 Performance test results of comparative examples 1 to 3

[0165]

[0166]

[0167] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a long-shelf-life algae oil drinkable room-temperature yogurt, characterized in that The following steps are involved: (1) heating milk to obtain milk liquid; (2) heating the algae oil and the vegetable oil to obtain a mixed liquid; (3) adding the mixed solution prepared in step (2), sugar, compound emulsifying thickener, and milk protein into the milk prepared in step (1), and shearing them uniformly; (4) homogenizing the liquid obtained in step (3); (5) sterilizing the liquid prepared in step (4); (6) cooling the liquid obtained in step (5); (7) adding the liquid prepared in step (6) to a fermentation agent for fermentation; (8) stopping the fermentation of the yogurt prepared in step (7) and stirring it evenly; (9) homogenizing the yogurt prepared in step (8); (10) sterilizing the yogurt obtained in step (9); (11) cooling the yogurt obtained in step (10); (12) filling the yogurt prepared in step (11) to prepare long-shelf-life algae oil drinkable room temperature yogurt; The dosage of each component is as follows by mass percentage: fresh milk 80% to 82%, sugar 6% to 8%, milk protein 0.5% to 1.0%, compound emulsifying thickener 1.5% to 2.0%, algae oil 0.035% to 0.1%, vegetable oil 0.07% to 0.2%, leavening agent 0.0003% to 0.0006%, and water as the balance; The composition of the compound emulsifying thickener is as follows: hydroxypropyl distarch phosphate, pectin and mono- and di-glycerol fatty acid esters are mixed in a mass ratio of (43.3-53.4): (40-43.3): (6.6-13.4).

2. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 1, characterized in that: The milk is fresh milk; The vegetable oil is at least one of soybean oil, corn oil and sunflower oil; The leavening agent is lactic acid bacteria.

3. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 2, characterized in that: The fermentation agents are thermophilic subspecies of Streptococcus salivarius and Bulgarian subspecies of Lactobacillus delbrueckii.

4. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 1, characterized in that: The sugar is syrup; The milk protein is concentrated milk protein.

5. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 4, characterized in that: The solid content of the syrup is 70-80% by mass; The syrup is at least one of fructose syrup, maltose syrup and corn syrup; The milk protein is concentrated milk protein with a protein content of 80-90% w / w.

6. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 1, characterized in that: The algae oil is pseudo-Nanococcus algae oil; The addition ratio of the algae oil to the vegetable oil is 1:2 by mass.

7. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 1, characterized in that: The heating temperature in step (1) is 53-58° C. The heating time in step (2) is 5 to 7 minutes; The shearing speed in step (3) is 2500-3500 r / min; The shearing time in step (3) is 10 to 15 minutes; The shearing temperature in step (3) is 50-55°C; The homogenization temperature in step (4) is 50-55°C; The homogenization pressure in step (4) is 18-22 MPa; The sterilization temperature in step (5) is 90-100°C; The sterilization time in step (5) is 5 minutes; The fermentation temperature in step (7) is 40-45°C; The fermentation time in step (7) is 6 to 8 hours; The pH for stopping the fermentation in step (8) is 4.3 to 4.4; The homogenization pressure in step (9) is 18-22 MPa; The sterilization method described in step (10) is ultra-high temperature sterilization.

8. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 7, characterized in that: The ultra-high temperature sterilization conditions are 121° C. and 3 to 5 seconds.

9. The method for preparing the long-shelf-life algae oil drinkable room-temperature yogurt according to claim 1, characterized in that: The cooling temperature in step (6) is below 50°C; The stirring speed in step (8) is 600-1000 r / min; The cooling temperature in step (11) is 25°C; The filling conditions described in step (12) are aseptic filling.

10. A long-shelf-life algae oil drinkable room-temperature yogurt, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 9.

Images