Method for separating casein from cream, cream enzymatic hydrolysate and preparation method of cream enzymatic hydrolysate

Abstract

The invention provides a method for separating casein from cream, cream enzymatic hydrolysate and a preparation method of the cream enzymatic hydrolysate. According to the method for separating the casein from the cream, the cream is cooled to be not higher than 4 DEG C, then the temperature is increased to T DEG C, the heated cream is subjected to casein separation treatment, T is larger than or equal to 20 and smaller than 36, and the fat content and stability of the cream are effectively improved.

Description

Technical Field

[0001] The invention relates to a method for separating buttermilk from cream, in particular to a method for separating buttermilk from cream, cream enzymatic hydrolysate and a preparation method thereof, and belongs to the field of food. Background Art

[0002] Cream is widely used in daily production and life, such as making ice cream, decorating cakes, cooking thick soup, and brewing coffee and tea. However, cream has disadvantages such as weak milk flavor, poor flavor, easy breeding of bacteria and sourness, and short shelf life. This leads to many food safety risks in the process of using cream and inconvenience in use.

[0003] In the existing process, lipase is used to enzymatically hydrolyze cream to obtain enzymatically hydrolyzed cream products, which significantly improves its milk flavor and flavor. In addition, many additives such as stabilizers, antioxidants, pigments, flavors, preservatives, etc. are added to improve its shortcomings such as easy bacterial growth and acidification and short shelf life. However, this also leads to a large amount of additives in the product, resulting in uneven product quality. Therefore, it is urgent to improve the preparation process of enzymatically hydrolyzed cream products to prepare more natural, safe, healthy, flavorful and stable enzymatically hydrolyzed cream products. Summary of the invention

[0004] The invention provides a method for separating buttermilk from cream. The method provides a new way for effectively removing the buttermilk from the cream, increasing the fat content of the cream, and further improving the stability of the cream.

[0005] The invention also provides a method for preparing a cream enzymatic hydrolysate. The cream enzymatic hydrolysate prepared by the method has a fat content of not less than 60%, contains a relatively large amount of short-chain saturated fatty acids, has a strong milky aroma, and has a good flavor. The cream enzymatic hydrolysate is not prone to bacterial growth and acidification, has good stability, and has a long shelf life.

[0006] The invention also provides a cream enzymatic hydrolysate, the fat content of which is not less than 60%, the acid value is 0.5-9.4 mg / g, and the peroxide value is 0.01-0.06 g / 100 g.

[0007] The invention provides a method for separating buttermilk from cream, comprising the following steps: cooling the cream to no more than 4°C, heating it to T°C, and performing buttermilk separation treatment on the heated cream; wherein 20≤T<36.

[0008] The present invention also provides a method for preparing a cream enzymatic hydrolysate, comprising the following steps:

[0009] 1) cooling the cream to not higher than 4° C., heating it to T° C., and performing at least one buttermilk separation process to obtain a first material, wherein 20≤T<36, and the fat content of the first material is ≥60%;

[0010] 2) Add lipase to the first material and perform enzymolysis for 2-4 hours to obtain a second material:

[0011] 3) heat-treating the second material to inactivate enzymes, thereby obtaining a cream enzymatic hydrolyzate.

[0012] In the preparation method as described above, the fat content of the first material is 60%-70%.

[0013] In the preparation method as described above, the mass proportion of the lipase in the mixture of the first material and the lipase is 0.65‰-3.5‰.

[0014] In the preparation method as described above, the fat content of the first material is ≥99%.

[0015] In the preparation method as described above, the mass proportion of the lipase in the mixture of the first material and the lipase is 0.991‰-4.995‰.

[0016] The preparation method as described above, wherein before step 2), further comprises washing the first material with water to obtain a washed product, wherein the fat content of the washed product is ≥99.5%.

[0017] The preparation method as described above further comprises vacuum drying the washed product to obtain a dried product, wherein the fat content of the dried product is 99.8%-99.9%.

[0018] The preparation method as described above, wherein, before the water washing, it also includes neutralizing the first material so that the acid value of the first material is 0.5-9.4 mg / g.

[0019] The present invention also provides a cream enzymatic hydrolysate, which is obtained by any of the preparation methods described above; the cream enzymatic hydrolysate has an acid value of 0.5-9.4 mg / g and a peroxide value of 0.01-0.06 g / 100 g;

[0020] Wherein, the fat content of the cream enzymatic hydrolysate is 60%-70%, or the fat content of the cream enzymatic hydrolysate is ≥99%.

[0021] The present invention provides a method for separating buttermilk from cream, which utilizes the difference in solubility of buttermilk in oil-water phases and the difference in freezing points of the oil-water phases to separate buttermilk dissolved in the water phase from the fat oil phase in the cream. The present invention provides a new method for separating buttermilk from cream, which is simple, convenient and easy to operate, effectively separates buttermilk from cream, reduces the protein content in cream, increases the fat content in cream, makes cream less likely to breed bacteria, improves its stability, and has broad application prospects. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The first aspect of the present invention provides a method for separating buttermilk from cream, comprising the following steps: cooling the cream to no higher than 4°C, heating it to T°C, and performing buttermilk separation on the heated cream; wherein 20≤T<36.

[0024] Cream is an O / W emulsion obtained by separating skim milk from raw milk, including fat, water, and buttermilk, wherein the buttermilk in cream has a greater solubility in water than fat. The present invention does not specifically limit the type of the cream, and the cream commonly used in the art can use the above method to remove buttermilk and increase fat content.

[0025] In detail, the freezing point of the water phase is 0°C, and the freezing point of the fat oil phase is 36°C. Therefore, by cooling the cream to no more than 4°C, the fat oil phase and most of the water phase in the cream can be solidified to form a solid state, and most of the buttermilk dissolved in the water phase also remains in a solid state. Subsequently, in order to improve the separation effect, the cooled cream is heated to a temperature of T°C, where 20≤T<36. At this time, the water phase in which buttermilk is dissolved in the cream can quickly melt to form a liquid state, with stronger fluidity, while the fat oil phase is still in a solid state. Therefore, through the solid-liquid separation operation, the buttermilk in the cream can be separated, so that the product after the buttermilk separation (i.e., the oil phase) has a higher fat content. It should be noted that when the cooling temperature is higher than 4°C, the buttermilk in the cream is prone to breed bacteria, become acidic, and then denature and precipitate, and cannot be removed with the water phase; when the temperature after heating is higher than 36°C, the fat oil phase is completely melted and miscible with the water phase, and the water phase cannot be separated, and the buttermilk cannot be separated.

[0026] The method provides a new way for separating buttermilk from cream, effectively separates buttermilk from cream, reduces the protein content in cream, increases the fat content in cream, makes cream less likely to breed bacteria, and improves its stability.

[0027] It is understandable that the above cooling temperature is preferably 0-4°C, when the cream is in a solidified state, and less heat and time are consumed in heating and melting at this time; similarly, the temperature after heating is preferably 25-30°C, when the water phase in the cream melts quickly and the buttermilk separation effect is better.

[0028] Furthermore, the present invention does not limit the temperature of the cream before cooling. However, when the initial temperature of the cream before cooling is ≥50°C, for example, 50-60°C, and further 50-55°C, the center temperature of the cream is ensured to reach above 36°C, so that it is completely melted, and the fat in the cream is evenly dispersed in the aqueous phase containing buttermilk in the form of small droplets. When it is cooled to no more than 4°C, the fat droplets will quickly separate from the aqueous phase containing buttermilk and solidify, and most of the buttermilk will remain in the aqueous phase, achieving a greater degree of separation between buttermilk and fat, and a better buttermilk separation effect.

[0029] It is understandable that the initial temperature of the cream can be raised to a state of ≥50° C. by preheating.

[0030] The present invention does not make any special limitation on the above-mentioned cooling and heating methods, and the commonly used methods in the field are applicable to the present invention. For example, the cream is pumped into a tank with an interlayer, and a proper amount of ice water is passed into the interlayer to cool the cream, and a proper amount of hot steam is passed to heat the cream.

[0031] The present invention also provides a method for preparing a cream enzymatic hydrolysate, comprising the following steps:

[0032] 1) cooling the cream to not higher than 4° C., heating it to T° C., and performing at least one buttermilk separation process to obtain a first material, wherein 20≤T<36, and the fat content of the first material is ≥60%;

[0033] 2) Add lipase to the first material and perform enzymolysis for 2-4 hours to obtain the second material:

[0034] 3) The second material is subjected to heat treatment to inactivate enzymes, thereby obtaining a cream enzymatic hydrolyzate.

[0035] The above-mentioned cream refers to cream with a fat content of 15%-35%, which is very easy to breed bacteria and turn sour, and has a short shelf life. For example, the shelf life is 6 months in an environment of -15°C; the shelf life is only 8-12 hours in an environment of 4-8°C. The cream can be purchased commercially or made by yourself according to conventional methods in the art. For example, the cream can be prepared according to the following method:

[0036] The raw milk is purified, standardized and pasteurized, then preheated to 50-55°C and the cream is obtained using a centrifugal separator.

[0037] The present invention does not specifically limit the raw milk, for example, it can be selected from at least one of whole milk, whole milk powder reconstituted milk, raw cow milk, whole goat milk, whole goat milk powder reconstituted milk, and raw goat milk. The purification, standardization, pasteurization, and centrifugal separation are all performed according to conventional technical means in the art, wherein the pasteurization condition is 95°C, 15s; the outlet pressure of the centrifuge is set at about 0.4 bar. It is understandable that the centrifuge is also called a fat separator.

[0038] The temperature of the cream separated by the centrifuge is relatively high, generally 50-55°C. The cream at this temperature is a uniform, milky white, slightly yellow O / W emulsion. When the temperature is cooled to no more than 4°C, the fat oil phase will quickly separate from the water phase and solidify to form a solid state. At the same time, most of the water phase will also solidify to form a solid state, while most of the buttermilk will remain in the water phase; when the temperature rises to T°C, where 20≤T<36, the water phase will quickly melt to become a white buttermilk liquid, while the fat oil phase will still be solid. At this time, the solid and the liquid can be completely separated, and the fat oil phase floats on the upper layer of the white buttermilk liquid. After the white buttermilk liquid at the lower layer is removed, the first material is obtained. The fat content of the first material is correspondingly increased, and the protein content is reduced, so that the product is not easy to breed bacteria and become sour, the stability is improved, and the shelf life is extended.

[0039] Carrying out at least one buttermilk separation process in the above step 1) means that after the solid phase residue is obtained by buttermilk separation, the fat content of the solid phase residue is detected, and when the fat content is less than 60%, the buttermilk separation process is repeated, that is, the operation of cooling to not higher than 4°C, heating to T°C, wherein 20≤T<36, and removing buttermilk is repeated until the fat content is ≥60%, that is, the first material is obtained. The number of buttermilk separation processes is related to factors such as the content of fat and buttermilk in the raw material, the total amount of the raw material, the degree of buttermilk separation, and the fat content of the product.

[0040] It is understandable that fatty acid content is generally used to represent fat content in the art. The present invention adopts GB5009.168 "Determination of Fatty Acids in Foods, National Food Safety Standard" to perform fatty acid detection, and the obtained fatty acid content is the fat content of the present invention.

[0041] The lipase used in the present invention refers to a lipase that meets the national enzyme preparation standard and the food additive standard GB 2760. After the lipase is added to the first material, the fat in the first material is decomposed to produce more short-chain saturated fatty acids, thereby reducing the fat smell of the product and improving the flavor of the product.

[0042] Enzymatic hydrolysis for 2-4 hours means that the content change of C4-C18 product in the product is detected at any time during the enzymatic hydrolysis process. When the content reaches a peak value, the enzymatic hydrolysis reaction can be terminated to obtain the second material. At this time, the enzymatic hydrolysis time is generally 2-4 hours.

[0043] The present invention does not specifically limit the conditions for the heat treatment to inactivate the enzyme, and conventional techniques in the art may be used, for example, heating the second material to 75-80° C. or 80-85° C. and maintaining the temperature for 5-10 minutes.

[0044] The fat content of the cream hydrolysate obtained by the method is not less than 60%. Compared with light cream, the cream hydrolysate is not easy to breed bacteria and become sour, has improved stability, significantly extended shelf life, contains more short-chain saturated fatty acids, and has a strong milky flavor and good flavor. In addition, the cream hydrolysate does not contain any additives and is more natural, safe and healthy.

[0045] The above step 1) can occur in a storage tank or a material tank, both of which are interlayer tanks. In the cooling stage, ice water is introduced into the interlayer to cool the cream; in the heating stage, hot steam is introduced into the interlayer to heat the cream; when the white buttermilk is separated, the valve at the bottom of the tank is opened to discharge the white buttermilk, and the remaining part is the first material. The present invention does not specifically limit the above cooling and heating methods, and conventional technical means in the field can be used.

[0046] It is understandable that the above cooling temperature is preferably 0-4°C, when the cream is in a solidified state, and less heat and time are consumed in heating and melting at this time; similarly, the temperature after heating is preferably 25-30°C, when the water phase in the cream melts quickly and the buttermilk separation effect is better.

[0047] The first material is cream after excluding buttermilk. In order to determine that the cream after excluding buttermilk meets the national standards, the first material must be subjected to necessary physical and chemical tests after it is obtained, such as color, texture, flavor, acidity, free fatty acids, peroxide value, etc.

[0048] In addition, when more than one buttermilk separation process is performed, a phase conversion operation can be performed between each two buttermilk separation processes to improve the buttermilk separation effect. Specifically, the phase conversion operation is completed by a homogenization operation to make the size of the fat particles uniform and keep the density difference consistent with other components in the cream. The homogenization conditions can be the conditions commonly used in the art, for example, the homogenization pressure is 130 bar-140 bar.

[0049] In the above step 2), before adding lipase, the temperature of the first material can be raised to 50-60°C. The first material is a uniform and transparent cream liquid. At this time, lipase is added and stirred evenly, which is conducive to the full dispersion of lipase in the first material and facilitates a more thorough enzymatic reaction.

[0050] The enzymatic hydrolysis reaction is carried out in an enzymatic hydrolysis tank. It is understandable that in order to avoid contamination by foreign bacteria and reduce the quality of the product, the tank mouth needs to be wiped and sterilized with alcohol cotton before adding lipase. Similarly, if the above-mentioned cream is commercially available, it should be pasteurized.

[0051] After the enzyme is inactivated, the material can be tested for enzyme activity. If the enzyme activity is lower than 10mu / ml, it indicates that the enzyme inactivation is successfully completed.

[0052] In actual production, the prepared cream enzymatic hydrolysate is generally cooled and then filled for use, or pumped into a material tank for preparation of other products.

[0053] The above filling means first filling the packaging container with inert gas nitrogen, then filling it with cream hydrolysate, and finally sealing the packaging container, which can prevent the cream hydrolysate from being oxidized and deteriorated. It is understandable that although the above filling can ensure that the quality of the cream hydrolysate is not reduced to a certain extent, it is still necessary to conduct a full physical and chemical inspection and microbiological sampling of the product before leaving the factory, and it can only be shipped after passing the inspection.

[0054] In a specific embodiment, the buttermilk separation process is performed once to obtain a first material with a fat content of 60%-70%. At this time, the fat content of the prepared cream hydrolysate is 60%-70%, the acid value is 0.5-9.4 mg / g, and the peroxide value is 0.01-0.06 g / 100 g. The cream hydrolysate is not easy to breed bacteria and become sour, has high stability, does not contain any additives, and is natural, safe, and healthy.

[0055] Furthermore, when preparing a cream hydrolysate with a fat content of 60%-70%, when the mass proportion of lipase in the mixture of the first material and lipase is 0.65‰-3.5‰, the enzymatic hydrolysis effect is good, which is manifested in that the prepared cream hydrolysate contains more short-chain fatty acids, has a strong milky flavor, a long-lasting aftertaste, and a better flavor.

[0056] In another specific embodiment, the above-mentioned buttermilk separation process is performed twice, that is, a first material with a fat content of ≥99.0% is obtained. In this case, it is beneficial to obtain a cream hydrolyzate with a fat content of ≥99%. Specifically, the fat content of the separated product is detected after each buttermilk separation. If the fat content is lower than 99.0%, the separated product is subjected to buttermilk separation again (i.e., cooled to no more than 4°C, and then heated to T°C, where 20≤T<36, to separate the buttermilk) until a separated product with a fat content of 99% is obtained. The separated product is the first material with a fat content greater than 99%. In this case, the buttermilk separation process is performed twice.

[0057] It is understandable that when more than one buttermilk separation process is performed, a phase conversion operation can be performed between each two buttermilk separation processes to improve the buttermilk separation effect. Specifically, the phase conversion operation is completed by a homogenization operation to make the size of the fat particles uniform and keep the density difference consistent with other components in the cream. The homogenization conditions can be the conditions commonly used in the art, for example, the homogenization pressure is 130 bar-140 bar.

[0058] Furthermore, when preparing a cream hydrolysate with a fat content of not less than 99%, when the mass proportion of lipase in the mixture of the first material and lipase is 0.991‰-4.995‰, the enzymatic hydrolysis effect is good, which is manifested in that the prepared cream hydrolysate contains more short-chain fatty acids, has a strong milky flavor, a long-lasting aftertaste, and a better flavor.

[0059] In order to further increase the fat content of the first material having a fat content of not less than 99%, before the enzymatic hydrolysis treatment in step 2), it is also included to wash it with hot water at 90±5°C to wash away water-soluble impurities, and obtain a washed product after centrifugation to remove water, and the fat content of the washed product is ≥99.5%.

[0060] Furthermore, by vacuum drying the water-washed product, a dry product having a fat content of 99.8% to 99.9% can be obtained.

[0061] The present invention does not limit the specific processing method of the above-mentioned vacuum dried product. For example, the dried product is cooled to 45±5°C and then filled for preparation. Before enzymatic hydrolysis, the canned dried product only needs to be pumped into the enzymatic hydrolysis tank and preheated to 50-60°C to make it a transparent liquid with a uniform state, and then enzymatic hydrolysis is performed. For another example, the temperature of the dried product is directly reduced to 50-60°C and then pumped into the enzymatic hydrolysis tank for enzymatic hydrolysis.

[0062] The dried product is subjected to enzymatic hydrolysis and enzyme inactivation treatment to obtain anhydrous butter enzymatic hydrolysate.

[0063] When the fat content in the cream is higher than 70%, its acid value may be higher than the range of 0.5-9.4 mg / g. Therefore, the acid value of the first material needs to be tested before the above-mentioned water washing. If the acid value is too high, the first material needs to be neutralized to keep the acid value of the first material at 0.5-9.4 mg / g, and then the acid value of the prepared cream enzymatic hydrolysate is also kept at 0.5-9.4 mg / g.

[0064] The present invention does not limit the specific method of the above neutralization, and can use the commonly used alkaline agent in the art for neutralization, for example, 10% NaHCO 3 The solution is added to the first material to neutralize excess free fatty acids and reduce the acid value of the product.

[0065] The present invention also provides a cream enzymatic hydrolysate, which is obtained by any of the above preparation methods; the acid value of the cream enzymatic hydrolysate is 0.5-9.4 mg / g, and the peroxide value is 0.01-0.06 g / 100 g; wherein the fat content of the cream enzymatic hydrolysate is 60%-70%, or the fat content of the cream enzymatic hydrolysate is ≥99%.

[0066] If the acid value and peroxide value are within the above range and remain stable during the shelf life, it means that the cream enzymatic hydrolysate has not been excessively oxidized and deteriorated, and has excellent and stable quality.

[0067] The cream hydrolysate is rich in short-chain saturated fatty acids, has a strong milky flavor, a lasting aftertaste and a good flavor; at the same time, it has a high fat content and a low protein content, is not easy to breed bacteria and become sour, and has high stability. Specifically, the cream hydrolysate with a fat content of 60%-70% can be stored for 7-14 days at 10-20°C, <40% RH in summer and <30% RH in winter, and the cream hydrolysate with a fat content of ≥99% can be stored for 12 months at 10-20°C, <40% RH in summer and <30% RH in winter. Compared with ordinary non-enzymatically hydrolyzed cream, the shelf life is significantly extended.

[0068] Compared with the enzymatically hydrolyzed cream products prepared by the traditional process, the enzymatically hydrolyzed cream solution provided by the present invention does not contain any additives and is natural, safe and healthy.

[0069] When the fat content reaches more than 99%, the cream enzymatic hydrolysate presents a uniform, clear and dark yellow color; when the fat content reaches 60-70%, the color presents a milky yellow or light yellow color; when the fat content is below 60%, the cream color presents a milky white or slightly yellow color.

[0070] Example 1

[0071] The method for preparing the cream enzymatic hydrolysate of this embodiment comprises the following steps:

[0072] 1) Purifying, standardizing and pasteurizing the raw milk, preheating it to 50-55° C., adding it to a centrifuge, adjusting the outlet pressure of the centrifuge to 0.35-0.4 bar, and collecting the cream;

[0073] 2) pumping the cream into a storage tank, passing ice water into the interlayer of the storage tank to cool the cream to 0-4° C., then passing hot steam into the interlayer of the storage tank to heat the cream to 25-30° C., opening the valve at the bottom of the tank, and draining white buttermilk to obtain a solid residue; repeating the above cooling-heating-draining buttermilk operation for the solid residue once to obtain a first material with a fat content of 60-70%;

[0074] 3) 999.35 g of the first material with a fat content of 60-70% was pumped into a cream enzymatic hydrolysis tank, preheated to 56.5° C., 0.65 g of lipase was added, stirred evenly, and enzymatic hydrolysis was performed for 3.5 hours to obtain a second material;

[0075] 4) The second material is heated to 75-80° C. and maintained at this temperature for 5 minutes to obtain a cream enzymatic hydrolyzate.

[0076] Example 2

[0077] The preparation method of the cream enzymatic hydrolysate in this embodiment is basically the same as that in Embodiment 1, except that the outlet pressure of the centrifuge is 0.42 bar; the fat content of the first material is 70%; and the addition amounts of the first material with a fat content of 70% and lipase are 996.5 g and 3.5 g, respectively.

[0078] Example 3

[0079] The preparation method of the cream enzymatic hydrolysate in this embodiment is basically the same as that in Embodiment 1, except that the outlet pressure of the centrifuge is 0.4 bar; the fat content of the first material is 70%; and the added amounts of the first material with a fat content of 70% and lipase are 997.9 g and 2.1 g, respectively.

[0080] Example 4

[0081] The method for preparing the cream enzymatic hydrolysate of this embodiment comprises the following steps:

[0082] 1) Purifying, standardizing and pasteurizing the raw milk, preheating it to 50-55° C., adding it to a centrifuge, adjusting the outlet pressure of the centrifuge to 0.35-0.4 bar, and collecting the cream;

[0083] 2) pumping the cream into a storage tank, passing ice water into the interlayer of the storage tank to cool the cream to 0-4° C., then passing hot steam into the interlayer of the storage tank to raise the temperature of the cream to 25-30° C., opening the valve at the bottom of the tank, draining the white buttermilk to obtain a solid phase residue, repeating the above cooling-heating-draining buttermilk operation twice on the solid phase residue to obtain a first material with a fat content of 98.5%; wherein, before repeating the above cooling-heating-draining buttermilk operation, homogenization is first performed, and the homogenization pressure is 130 bar-140 bar;

[0084] 3) Add 10% NaHCO to the first material 3 solution, so that the free acid value in the first material meets the standard requirements, and a neutralized product is obtained;

[0085] 4) preheating the neutralized product to 95° C., washing the neutralized product with hot water at 90° C., and then removing water with a separator to obtain a washed product with a fat content greater than 99.5%;

[0086] 5) subjecting the washed product to vacuum drying and dehydration treatment to obtain a dry product having a fat content of 99.8% to 99.9%;

[0087] 6) After the dried product is cooled to 45±5° C., 997.003 g of the dried product is pumped into a cream enzymolysis tank, preheated to 50-60° C., 2.997 g of lipase is added, stirred evenly, and enzymolyzed for 4 hours to obtain a second material;

[0088] 7) The temperature of the enzymatic hydrolysate was raised to 80-85° C. and maintained for 5 min to obtain a cream enzymatic hydrolysate.

[0089] Example 5

[0090] The preparation method of the cream enzymatic hydrolysate in this example is basically the same as that in Example 4, except that the added amounts of the dry product and lipase are 995.005 g and 4.995 g, respectively.

[0091] Example 6

[0092] The preparation method of the cream enzymatic hydrolysate in this example is basically the same as that in Example 3, except that the cooling temperature is -4-0°C.

[0093] Example 7

[0094] The preparation method of the cream enzymatic hydrolysate in this embodiment is basically the same as that in embodiment 3, except that the temperature after heating is 20-25°C.

[0095] Example 8

[0096] The preparation method of the cream enzymatic hydrolysate in this embodiment is basically the same as that in embodiment 3, except that the temperature after heating is 30-35°C.

[0097] Example 9

[0098] The preparation method of the cream enzymatic hydrolysate in this example is basically the same as that in Example 4, except that the added amounts of the dry product and lipase are 998.006 g and 1.994 g, respectively.

[0099] Example 10

[0100] The preparation method of the cream enzymatic hydrolysate in this example is basically the same as that in Example 4, except that the cooling temperature is -4-0°C.

[0101] Embodiment 11

[0102] The preparation method of the cream enzymatic hydrolysate in this embodiment is basically the same as that in embodiment 4, except that the temperature after heating is 20-25°C.

[0103] Example 12

[0104] The preparation method of the cream enzymatic hydrolysate in this embodiment is basically the same as that in embodiment 4, except that the temperature after heating is 30-35°C.

[0105] Example 13

[0106] The preparation method of the cream enzymatic hydrolysate in this embodiment is basically the same as that in embodiment 3, except that the added amounts of the first material having a fat content of 70% and the lipase are 999.8 g and 0.2 g, respectively.

[0107] Embodiment 14

[0108] The preparation method of the cream enzymatic hydrolysate in this example is basically the same as that in Example 3, except that the added amounts of the first material having a fat content of 70% and the lipase are 994 g and 6 g, respectively.

[0109] Embodiment 15

[0110] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 4, except that the added amounts of the dry product and lipase are 999.9 g and 0.1 g, respectively.

[0111] Example 16

[0112] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 4, except that the added amounts of the dry product and lipase are 993 g and 7 g, respectively.

[0113] Comparative Example 1

[0114] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 1, except that the enzymatic hydrolysis time is 6 h.

[0115] Comparative Example 2

[0116] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 5, except that the enzymatic hydrolysis time is 1 h.

[0117] Comparative Example 3

[0118] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 3, except that the cooling temperature in step 2) is higher than 4° C. and lower than 8° C., and the above cooling-heating-buttermilk removal operation is repeated once for the solid phase residue, and the fat content of the solid phase residue is detected to be 67%.

[0119] Comparative Example 4

[0120] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 3, except that the temperature after heating in step 2) is 36-40° C., and the solid phase residue is repeatedly subjected to the above cooling-heating-buttermilk removal operation once, and the fat content of the solid phase residue is detected to be 32%.

[0121] Comparative Example 5

[0122] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 4, except that the cooling temperature in step 2) is 8-12° C., and the above cooling-heating-buttermilk removal operation is repeated twice on the solid phase residue, and the fat content of the solid phase residue is detected to be 85%.

[0123] Comparative Example 6

[0124] The preparation method of the cream enzymatic hydrolysate in this comparative example is basically the same as that in Example 4, except that the temperature after heating in step 2) is 36-40° C., and the above cooling-heating-buttermilk removal operation is repeated twice on the solid phase residue, and the fat content of the solid phase residue is detected to be 34%.

[0125] Test example

[0126] 1. The following parameters of the above embodiments and comparative examples were tested:

[0127] 1) Fatty acid content detection: Fatty acid detection was carried out in accordance with GB 5009.168 "National Food Safety Standard Determination of Fatty Acids in Foods". The test results of the first week are shown in Table 1;

[0128] 2) Acid value: Acid value test was conducted in accordance with GB 5009.229-2016 "National Food Safety Standard - Determination of Acid Value in Foods". The test results for the first week are shown in Table 1;

[0129] 3) Peroxide value: The peroxide value was tested in accordance with GB 5009.227-2016 "National Food Safety Standard - Determination of Peroxide Value in Foods". The test results for the first week are shown in Table 1;

[0130] 4) Sensory evaluation: sensory evaluation was conducted on the flavor and color of the product. According to the standard of sensory analysis method of GB / T12311, a 5-point system was designed to evaluate the flavor. 5 points represented strong milk flavor, lasting aftertaste, and better flavor. 4 points represented obvious milk flavor, long aftertaste, and good flavor. 3 points represented average milk flavor, weak aftertaste, and average flavor. 2 points represented light milk flavor, almost no aftertaste, and poor flavor. 1 point represented unclear milk flavor, no aftertaste, and poor flavor. "+" represented slightly better, and "-" represented slightly weaker. The color of the product was evaluated according to uniform, clear, dark yellow, milky yellow, light yellow, slightly yellow, milky white, and other colors. The evaluators were professional and technical personnel, and the number of evaluators met the requirements of the above standards. The score was given at one time. The specific results are shown in Table 2.

[0131] 5) Shelf life: The flavor, acid value and peroxide value of the product are tested once on the first day of each week. If the test values ​​meet the standard range, the product is qualified and the test is continued for the next week. If the test values ​​are qualified for two consecutive weeks, the product is tested once a month. When at least one of the test values ​​of flavor, acid value and peroxide value exceeds the standard range, the product reaches the shelf life. The specific results of the shelf life are shown in Table 3.

[0132] 2. Test results

[0133] Table 1 Fatty acid content, acid value and peroxide value of cream enzymatic hydrolysate

[0134]

[0135]

[0136] As shown in Table 1, the fatty acid contents of Examples 1-3, 6-8, 13, and 14 are all 60-70%, and the fatty acid contents of Examples 4, 5, 9-12, 15, and 16 are all above 99%, which proves that by cooling the cream to no higher than 4°C and then heating it to a temperature no lower than 20°C and lower than 36°C, buttermilk can be effectively separated and the fatty acid content can be increased; the fatty acid content of Comparative Example 1 is 65%, the fatty acid content of Comparative Example 2 is 99.1%, and the fatty acid content of Comparative Examples 3 and 4 is significantly lower than that of Example 3; the fatty acid content of Comparative Examples 5 and 6 is significantly lower than that of Example 4;

[0137] The acid values ​​of Examples 1-16 are all between 0.5 and 9.4 mg / g, and the peroxide values ​​are all between 0.01 and 0.06 g / 100 g, which proves that the enzymatic hydrolyzate of cream prepared by the present invention is not easy to breed bacteria and become sour, is not easy to oxidize, and has good stability; the acid value and peroxide value of Comparative Example 1 are both higher than the standard range, which may be due to the fact that the enzymatic hydrolysis time is too long and the fat is excessively oxidized, resulting in an increase in the acid value and peroxide value; the acid value and peroxide value of Comparative Example 2 are within the normal range; the acid value and peroxide value of Comparative Examples 3-6 are both higher than the standard range, because the buttermilk removal effect is poor, the fat content is low, and the water content is high, which accelerates fat oxidation.

[0138] Table 2 Sensory evaluation results

[0139] sample Flavor / min Color sample Flavor / min Color Example 1 5 Cream yellow Example 13 4 Cream yellow Example 2 5 Cream yellow Embodiment 14 4+ Cream yellow Example 3 5+ Cream yellow Embodiment 15 4 Dark yellow Example 4 5+ Uniform clear dark yellow Example 16 4+ Dark yellow Example 5 5 Uniform clear dark yellow Comparative Example 1 3 Light yellow Example 6 5 Cream yellow Comparative Example 2 3- Dark yellow Example 7 5 Cream yellow Comparative Example 3 3 Milky white Example 8 5 Cream yellow Comparative Example 4 3- Creamy white with a slight hint of yellow Example 9 5 Uniform clear dark yellow Comparative Example 5 3- Dark yellow Example 10 5 Dark yellow Comparative Example 6 2 Dark yellow Embodiment 11 5 Dark yellow Example 12 5 Uniform clear dark yellow

[0140] As shown in Table 2, Examples 1-12 have strong milk flavor, lasting aftertaste, and better flavor. Examples 13-16 have obvious milk flavor, long aftertaste, and good flavor. Comparative Examples 1-6 have milk flavors that are worse than those of the Examples, with average milk flavor, weak aftertaste, and average flavor. This is because the enzymolysis time is too long or too short, the amount of enzyme added is too much or too little, the degree of enzymolysis, the moisture content of the product, and the buttermilk content, etc., all affect the flavor of the product.

[0141] When the fat content reaches more than 99%, the cream appears uniformly clear dark yellow to dark yellow; when the fat content reaches 60-70%, the cream color appears milky yellow or light yellow; when the fat content is below 60%, the cream color appears milky white with a slight yellow tint.

[0142] Table 3 Shelf life of cream enzymatic hydrolysate

[0143] sample Shelf life sample Shelf life Example 1 14 days Example 13 13 days Example 2 14 days Embodiment 14 13 days Example 3 14 days Embodiment 15 12 months Example 4 12 months Example 16 12 months Example 5 12 months Comparative Example 1 8 hours Example 6 14 days Comparative Example 2 1 month Example 7 14 days Comparative Example 3 4 hours Example 8 14 days Comparative Example 4 8 hours Example 9 12 months Comparative Example 5 1 month Example 10 12 months Comparative Example 6 1 month Embodiment 11 12 months Example 12 12 months

[0144] As shown in Table 3, the shelf life of the products of Examples 1-3 and 6-8 can reach 14 days, and the shelf life of Examples 13 and 14 is 13 days; the shelf life of the products of Examples 4, 5, 9-12, 15 and 16 can reach 12 months; while the comparative example 1 has excessive oxidation due to the long enzymatic hydrolysis time, and the acid value and peroxide value increase rapidly, exceeding the standard range, and the shelf life is only 8 hours; the enzymatic hydrolysis time of comparative example 2 is too short, the flavor is not good, and the shelf life is short; the buttermilk removal effect of comparative examples 3-6 is poor, and it is easy to breed bacteria and turn sour, easy to oxidize and deteriorate, the flavor is not good, and the shelf life is short.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for separating buttermilk from cream, characterized in that: After cooling the cream to no higher than 4°C, the cream is heated to T°C and subjected to buttermilk separation treatment; wherein 20≤T<36.

2. A method for preparing a cream enzymatic hydrolysate, characterized in that: The following steps are involved: 1) cooling the cream to not higher than 4° C., heating it to T° C., and performing at least one buttermilk separation process to obtain a first material, wherein 20≤T<36, and the fat content of the first material is ≥60%; 2) Add lipase to the first material and perform enzymolysis for 2-4 hours to obtain a second material: 3) heat-treating the second material to inactivate enzymes, thereby obtaining a cream enzymatic hydrolyzate.

3. The preparation method according to claim 2, characterized in that: The fat content of the first material is 60%-70%.

4. The preparation method according to claim 3, characterized in that: The mass proportion of the lipase in the mixture of the first material and the lipase is 0.65‰-3.5‰.

5. The preparation method according to claim 2, characterized in that: The fat content of the first material is ≥99%.

6. The preparation method according to claim 5, characterized in that: The mass proportion of the lipase in the mixture of the first material and the lipase is 0.991‰-4.995‰.

7. The preparation method according to claim 5 or 6, characterized in that: Before step 2), the method further comprises washing the first material with water to obtain a washed product, wherein the fat content of the washed product is ≥ 99.5%.

8. The preparation method according to claim 7, characterized in that: The method also includes vacuum drying the washed product to obtain a dried product, wherein the fat content of the dried product is 99.8%-99.9%.

9. The preparation method according to claim 7 or 8, characterized in that: Before the water washing, the first material is subjected to a neutralization treatment so that the acid value of the first material is 0.5-9.4 mg / g.

10. A cream enzymatic hydrolysate, characterized in that: The cream enzymatic hydrolysate is obtained by the preparation method according to any one of claims 2 to 9; the acid value of the cream enzymatic hydrolysate is 0.5-9.4 mg / g, and the peroxide value is 0.01-0.06 g / 100 g; Wherein, the fat content of the cream enzymatic hydrolysate is 60%-70%, or the fat content of the cream enzymatic hydrolysate is ≥99%.

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