阅读说明：本技术 一种c52结构脂的酶法合成方法 (Enzymatic synthesis method of C52 structural lipid ) 是由 王小三 黄卓能 黄雅祺 王笑寒 时旺旭 江聪 于 2021-09-18 设计创作，主要内容包括：本发明公开了一种C52结构脂的酶法合成方法,属于食品加工技术领域。本发明利用一步法合成C52结构脂,采用蒸馏或吸附的方法降低棕榈硬脂或其分提产物的过氧化值至3mmol/kg以下,以实现维持脂肪酶的活性的目的,从而提高反应过程中脂肪酶的利用率。本发明提供了一种高产量、高效率、低成本的酶法合成C52结构脂的方法,避免了目前酶法合成C52结构脂成本高且利用率低的弊端,有巨大的潜力推动工业化大批量生产。(The invention discloses an enzymatic synthesis method of C52 structure lipid, belonging to the technical field of food processing. The invention utilizes a one-step method to synthesize C52 structure fat, and adopts a distillation or adsorption method to reduce the peroxide value of palm stearin or a separation product thereof to be below 3mmol/kg so as to achieve the purpose of maintaining the activity of lipase, thereby improving the utilization rate of the lipase in the reaction process. The invention provides a method for synthesizing C52 structure fat by an enzyme method with high yield, high efficiency and low cost, which avoids the defects of high cost and low utilization rate of C52 structure fat synthesized by the existing enzyme method and has great potential to promote industrial mass production.)

1. An enzymatic synthesis method of C52 structural lipid is characterized by comprising the following steps:

s1, raw material treatment: carrying out peroxide value reduction treatment on a palm oil extract with an iodine value of 8g/100 g-30 g/100g, wherein the peroxide value needs to be reduced to below 3 mmol/kg;

synthesis of S2 and C52 structural lipid: mixing the palm oil fraction treated by the S1 with free fatty acid rich in oleic acid and linoleic acid, reacting under the catalysis of lipase, removing the lipase and the free fatty acid after reacting for a certain time to obtain structural fat rich in C52, and deodorizing the structural fat.

2. The method as claimed in claim 1, wherein the peroxide number reducing treatment method of the raw material of the step S1 includes either or both of a distillation method and an adsorption method.

3. The method of claim 2, wherein the distillation method comprises either or both of deodorization, molecular distillation.

4. A process according to claim 3, characterized in that the deodorization is carried out at a temperature of 230 to 265 ℃ for 30 to 120min and at an operating pressure of not more than 6 mbar; the evaporation surface temperature of the molecular distillation is 230-270 ℃.

5. The method according to claim 2, wherein the adsorbent for the adsorption method comprises one or more of silica gel, activated clay, activated carbon, zeolite, diatomite, silica and attapulgite, and the reaction time of the adsorption method is less than 50 min.

6. The method according to claim 5, wherein the adsorbent of the adsorption method is silica gel or activated carbon.

7. The method according to any one of claims 1 to 6, wherein the free fatty acid rich in oleic acid and linoleic acid in the S2 step is derived from natural oil, and the natural oil comprises vegetable oil and animal oil.

8. The method as claimed in any one of claims 1 to 7, wherein the lipase used in step S2 includes any one or more of Rhizopus oryzae (Rhizopus oryzae), Burkholderia cepacia (Burkholderia cepacia), Rhizopus nigricans (Rhizomucormihei) as a source of lipase.

9. The method according to any one of claims 1 to 8, wherein the reaction temperature for synthesizing the C52 structured lipid in the S2 step is 45 ℃ to 75 ℃, and the reaction time is 2h to 14 h.

10. Use of the preparation method according to any one of claims 1 to 9 in the field of preparing a formula milk powder.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to an enzymatic synthesis method of C52-structured lipid.

Background

The breast milk fat has a certain particularity, and the breast milk fat contains 1, 3-polyunsaturated fatty acid-2-saturated fatty acid triglyceride such as OPO and OPL with high content, which are beneficial to the digestion and absorption of infants and reduce constipation, and can also play an active promoting role in bone strengthening, gastrointestinal maturation and the like. Because of the characteristic of breast milk fat, more and more infant formula milk powder manufacturers apply 'complete breast milk substitute fat' to the design and production of infant formula milk powder, and the milk fat is used as a template, so that the high similarity between the infant milk powder and the breast milk is continuously pursued, and the milk powder product more suitable for infants in China is researched and developed. In recent years, research on synthesizing OPO and OPL structural fat and using the OPO and OPL structural fat in breast milk fat substitutes is hot, and the OPO structural fat products on the market have been approved abroad, but a better production method and formula milk powder more suitable for the physique of Chinese babies are searched at present in China.

At present, chemical catalysis, solvent extraction, enzymatic synthesis and the like are used as methods for synthesizing C52 type mother milk substitute fat such as OPO, OPL and the like in industrial production. Compared with the traditional chemical catalysis method, the enzymatic catalysis method has the characteristics of high activity, mild reaction conditions, strong specificity and the like, and the nutritional value of the breast milk substitute fat product synthesized by the enzymatic catalysis method is closer to that of the mother milk fat. However, in practical industrial applications, the price of the enzyme is high, mass production needs to be considered more cost, and the improvement of the production and utilization efficiency of the enzyme becomes a key point under the condition that the enzyme cost cannot be reduced.

At present, the method for producing the lipase used by C52 type breast milk to replace fat has less times of recycling and improves the utilization rate of the lipase, is mostly not favorable for continuous production, and the breast milk replacing fat product which is not commercialized at present is on the market, so that the method has certain practical significance if the problem of low utilization rate of the lipase can be solved from the source.

Disclosure of Invention

[ problem ] to

The existing lipase for producing C52 type mother milk substitute fat (hereinafter referred to as C52 structure fat) has high cost, less repeated utilization times or low utilization rate.

[ solution ]

The method carries out peroxide value reduction treatment on the palm oil extract from the source, and then adopts a one-step method to synthesize the C52 structure fat, so that the utilization rate of enzyme can be greatly improved while high yield is ensured, and the method has great significance for industrial production.

Specifically, the invention provides the following technical scheme: a method for the enzymatic synthesis of C52 structural lipids, the method comprising the steps of:

s1, raw material treatment: carrying out peroxide value reduction treatment on a palm oil extract with an iodine value of 8g/100 g-30 g/100g, wherein the peroxide value needs to be reduced to below 3 mmol/kg;

synthesis of S2 and C52 structural lipid: mixing the palm oil fraction treated by the S1 with free fatty acid rich in oleic acid and linoleic acid, reacting under the catalysis of lipase, removing the lipase and the free fatty acid after reacting for a certain time to obtain structural fat rich in C52, and deodorizing the structural fat.

Preferably, in the step S1, the iodine value of the palm oil extract ranges from 10g/100g to 18g/100 g.

Preferably, in the step S1, the peroxide number reducing treatment method for the raw material includes either or both of a distillation method and an adsorption method.

Preferably, the distillation method comprises either or both of deodorization, molecular distillation.

Preferably, the temperature of deodorization is 230-265 ℃, the time is 30-120 min, and the operating pressure is not higher than 6 mbar.

Preferably, the temperature of an evaporation surface of the molecular distillation is 230-270 ℃, and the operating pressure is 4-10 mbar.

Preferably, the reaction time of the adsorption method is 50min or less.

Preferably, the adsorbent of the adsorption method comprises one or more of silica gel, activated clay, activated carbon, zeolite, diatomite, silicon dioxide and attapulgite, and preferably silica gel and activated carbon.

Preferably, the free fatty acid rich in oleic acid and linoleic acid in the step S2 is derived from natural oil.

Preferably, the natural oil comprises vegetable oil and fat and animal oil and fat.

Preferably, the vegetable oil includes, but is not limited to, any one or more of high oleic sunflower oil, soybean oil, peanut oil, corn oil, rice bran oil, sesame oil and olive oil.

Preferably, the animal fat includes, but is not limited to, any one or more of donkey oil, horse oil, lard and chicken oil.

Preferably, the lipase used in the step S2 includes any one or more of lipases derived from Rhizopus oryzae (Rhizopus oryzae), burkholderia cepacia (burkholderia cepacia), and Rhizopus oryzae (Rhizopus nigricans).

Preferably, the Lipase includes Lipase DF IM derived from Rhizopus oryzae (Rhizopus oryzae), Lipase PS and/or Lipase AK derived from Burkholderia cepacia (Burkholderia cepacia), Lipozyme RM IM and/or Lipozyme RM derived from Rhizopus nigricans (Rhizomucormihei).

Preferably, the addition amount of the lipase is 4-16%, preferably 6-14% of the total mass of the reactants.

Preferably, the reaction temperature for synthesizing the C52 structural ester in the S2 step is 45-75 ℃, and preferably 50-65 ℃; the reaction time is 2-14 h, preferably 4-8 h.

Preferably, in step S2, the molar ratio of the palm oil extract to the free fatty acid rich in oleic acid and linoleic acid is 1:6 to 1:18, preferably 1:10 to 1: 14.

Preferably, in step S2, the free fatty acid rich in oleic acid and linoleic acid has a molar ratio of oleic acid to linoleic acid of 1:0.3 to 1:3, preferably 1:0.6 to 1: 1.2.

The invention also provides application of the method in the field of preparation of formula milk powder.

The invention has the beneficial effects that:

according to the invention, the raw materials required for synthesizing the C52-structured lipid by the enzyme method are subjected to peroxide value reduction treatment, so that the activity of the lipase in the process of synthesizing the C52-structured lipid by the enzyme method is better retained, the recycling times of the enzyme can be effectively increased, and the defects of high cost and low utilization rate of the lipase in the industrial production process are overcome.

Drawings

FIG. 1 is a liquid chromatogram (evaporative light detector) of C52 triglyceride obtained after lipase is used 3 times in raw materials with or without adsorption treatment, wherein FIG. 1a is a liquid chromatogram of C52 structure lipid obtained after lipase is used 3 times in raw materials with adsorption treatment in example 4, and FIG. 1b is a liquid chromatogram of C52 structure obtained after lipase is used 3 times in raw materials with or without adsorption treatment in example 4.

Detailed Description

The present invention is further described below with reference to examples, but the embodiments of the present invention are not limited thereto.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with examples are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Method for analyzing C52 structural lipids:

operating methods and parameters of HPLC-ELSD detection: refer to highlight { highlight, Yuxu Wei, Zhoufeng, et al, research on enzymatic synthesis of 1-oleic acid-2-palmitic acid-3-linoleic acid triglyceride structured lipid [ J ]. China oil, 2020,45(08):66-70 }.

C52 structural lipids include OPO, OPL, LPL and POS.

2. Peroxide value analysis method: the peroxide value is determined by referring to a method of GB5009.227-2016 determination of peroxide value in food safety national standard food.

Example 1: (reaction temperature optimization)

(1) Raw material treatment: deodorizing palm oil extract with peroxide value of 5.8mmol/kg and iodine value of 14g/100g at 265 deg.C under 4mbar for 90 min; the peroxide value of the treated raw material is reduced to 2.4 mmol/kg.

(2) C52 structural lipid synthesis: adding a free fatty acid mixture rich in oleic acid and linoleic acid (weighed according to the molar ratio of palm stearin fraction: oleic acid: linoleic acid: 1:8: 6) into the treated palm oil extract, adding lipase Lipozyme RM IM derived from rhizopus oryzae (Rhizomucormieihei) with the enzyme addition amount of 10% (w/w relative to the total mass of reactants), mixing the mixture in a 50mL batch enzyme sandwich reactor, quickly raising the temperature to a certain temperature, and reacting for 8 hours. After the reaction is finished, recovering lipase and removing free fatty acid to obtain structural fat rich in C52, deodorizing the obtained structural fat under the condition of (1), and finally detecting the content of C52 triglyceride by using HPLC-ELSD.

The influence of the reaction temperature in the step (2) on the content of C52 structural lipid in the product synthesized by ester exchange is researched, the result is shown in Table 1, and the increase of the enzyme catalysis temperature is favorable for increasing the content of C52 structural lipid, and when the temperature is increased to be more than 60 ℃, the effect of continuously increasing the reaction temperature on the content of C52 structural lipid is not obvious.

TABLE 1 influence of the reaction temperature in the (2) th step on the C52-structured fat content in the synthesized product

Example 2: (reaction time optimization)

(1) Raw material treatment: deodorizing palm oil extract with peroxide value of 6.3mmol/kg and iodine value of 16g/100g at 265 deg.C under 4mbar for 90 min; the peroxide value of the treated raw material is reduced to 2.7 mmol/kg.

(2) C52 structural lipid synthesis: adding a free fatty acid mixture rich in oleic acid and linoleic acid (weighed according to the molar ratio of palm stearin fraction to oleic acid: linoleic acid: 1:8: 6) into the treated palm oil extract, adding lipase DF IM (lipase DF) derived from Rhizopus oryzae (Rhizopus oryzae) with the enzyme addition amount of 12% (w/w, relative to the total mass of reactants), mixing in a 50mL batch enzyme sandwich reactor, rapidly heating to 65 ℃, and reacting for a certain time. After the reaction is finished, recovering lipase and removing free fatty acid to obtain structural fat rich in C52, deodorizing the obtained structural fat under the condition of (1), and finally detecting the content of C52 triglyceride by using HPLC-ELSD.

The influence of the reaction time in the step (2) on the content of C52 structural lipid in the product of the transesterification synthesis is studied, and the results are shown in Table 2, so that the content of C52 structural lipid in the product can be improved by increasing the reaction time.

TABLE 2 Effect of the reaction time of step (2) on the content of C52-structured lipids in the synthesized product

Example 3: (method of treating raw Material)

(1) Raw material treatment: the palm oil extract with peroxide value of 5.4mmol/kg and iodine value of 15g/100g was treated to reduce peroxide value, and the method for reducing peroxide value is shown in Table 3 (the peroxide value is reduced to below 3 mmol/kg).

(2) C52 structural lipid synthesis: adding a free fatty acid mixture rich in oleic acid and linoleic acid (weighed according to the molar ratio of palm stearin fraction: oleic acid: linoleic acid: 1:8: 6) into the treated palm oil extract, adding lipase DF IM derived from Rhizopus oryzae (Rhizopus oryzae) with the enzyme addition amount of 12% (w/w, relative to the total mass of reactants), mixing in a 50mL batch enzyme sandwich reactor, and rapidly heating to 65 ℃ for 8 h. After the reaction is finished, recovering lipase and removing free fatty acid to obtain structural lipid rich in C52, and deodorizing the structural lipid under the conditions of 265 ℃, 4mbar and 90 min.

And (3) adding the lipase recovered in the step (2) into the next reaction for synthesizing the C52 structured fat by the enzyme method, wherein the rest conditions are consistent with those of the first reaction, and after 12 times of repeated use, detecting the content of the C52 structured fat by using HPLC-ELSD.

The influence of the raw materials on the maintenance condition of the activity of the used lipase after being treated by different peroxide value reducing methods, namely molecular distillation, deodorization and adsorption, is researched, the conditions under each method are optimized, and the content of C52 structural lipid obtained after the lipase is repeatedly used for 12 times under different conditions of each method is respectively measured, and the table 3 shows. The same material was used in the control group, but without any treatment, and was also reused 12 times.

TABLE 3C 52 structural fat content obtained after 12 uses of the enzyme in example 3 (with or without treatment of the reaction substrate with a peroxide number reduction)

As can be seen from Table 3, the recycling rate of the enzyme can be effectively improved by using distillation and adsorption methods to treat the raw materials, and the enzyme activity is still retained to a certain extent after 12 times of use.

Example 4:

(1) raw material treatment: adsorbing palm oil extract with peroxide value of 4.6mmol/kg and iodine value of 17g/100g by adding 1% silica gel at room temperature for 20 min; the peroxide value of the treated raw material is reduced to 1.2 mmol/kg.

(2) C52 structural lipid synthesis: adding a free fatty acid mixture rich in oleic acid and linoleic acid (weighed according to the molar ratio of palm stearin fraction: oleic acid: linoleic acid: 1:8: 6) into the treated palm stearin fraction, adding lipase Lipozyme RM IM derived from Rhizopus oryzae (Rhizomucormihei) with the enzyme addition amount of 10% (w/w, relative to the total mass of reactants), mixing the mixture in a 50mL batch enzyme sandwich reactor, and rapidly heating to 65 ℃ for reacting for 8 h. After the reaction is finished, recovering lipase and removing free fatty acid to obtain structural fat rich in C52, and deodorizing the structural fat under the conditions of 265 ℃, 4mbar and 90 min.

And (3) adding the lipase recovered in the step (2) into the next reaction for synthesizing the C52 structured fat by the enzyme method, wherein the rest conditions are consistent with those of the first reaction, and after 3 times of repeated use, detecting the content of the C52 structured fat by using HPLC-ELSD.

The influence of the adsorption treatment and non-adsorption treatment of the raw materials on the recycling effect of the enzyme in the step (2) is researched: the contents of C52-structured lipids obtained after 3 times of enzyme recycling under the above two conditions were measured, respectively, and are shown in Table 4.

TABLE 4 influence of the raw materials on the content of C52-structured lipids with or without adsorption treatment

As shown in FIG. 1, FIG. 1a is a C52 structural lipid liquid chromatogram obtained after the lipase in example 4 is used 3 times in the raw material subjected to adsorption treatment, and FIG. 1b is a C52 structural lipid liquid chromatogram obtained after the lipase in example 4 is used 3 times in the raw material not subjected to adsorption treatment. The data are summarized in table 4, and it can be seen that the lipase synthesized C52-structured lipid in the raw material after adsorption treatment after 3 times of use is higher, indicating that the lower the peroxide value of the raw material, the more beneficial the maintenance of the enzyme activity, the higher the content of the obtained C52-structured lipid, and thus the more times of recycling the enzyme. It is predicted that the treatment in the industrial production can greatly improve the enzyme treatment amount and reduce the cost.

When other lipases of the invention are used, the method of the invention can also effectively maintain the activity of the enzyme, increase the recycling times of the enzyme, and thus realize the improvement of the utilization rate of the enzyme.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.