Background
Resistant starch (also known as resistant starch and indigestible starch) which is not enzymatically hydrolyzed in the small intestine but is fermentatively reacted with volatile fatty acids in the human gastrointestinal colon. Resistant starches are present in certain natural foods, such as potato, banana, rice, etc., which contain resistant starches, and in particular high amylose corn starches contain up to 60% resistant starch. This starch is more resistant to degradation than other starches, is digested more slowly in the body, and is absorbed more slowly and enters the blood stream. The fiber has the property similar to soluble fiber and has certain slimming effect, and is favored by beauty lovers in recent years. The resistant starch can resist the decomposition of enzyme, slowly release glucose in vivo, has low insulin reaction, can control blood sugar balance, and reduce hunger sensation, and is especially suitable for diabetic patients.
The resistant starch can be used in food products, including medical foods and dietary supplements, to maintain colon health and integrity of the intestinal mucosa. The resistant starch may also be used as a drug. It has been linked to a number of colon diseases, including a decrease in the incidence of cancer. In addition, resistant starch may also reduce the occurrence of a cascade of metabolic syndromes, including insulin resistance, hyperglycemia, blood hyperinsulinemia, dyslipidemia, blood fibrinolysis disorders, diabetes, hypertension, and cardiovascular disease. Resistant starches may also be used to control obesity.
For example, chinese patent document CN104938904A (application No. 201410139000.X) discloses staple food flour for fatty liver patients to eat. Mainly comprises the following components in percentage by mass: 60 to 70 parts of wheat special flour, 8 to 9 parts of soybean protein powder, 10 to 11 parts of soybean powder, 4 to 5 parts of wheat protein powder, 4 to 5 parts of resistant starch, 3 to 4 parts of konjac powder and 3 to 5 parts of resistant dextrin. The eclipta carignata health food is convenient to eat, does not increase blood fat after a person with fatty liver eats the eclipta carignata health food, has good taste, and can reduce the content of the fat in the eclipta carignata and reduce the blood fat. The product has the characteristics of high protein, high dietary fiber, high vitamins and low carbohydrate, is composed of natural raw grains, has no additive or medical substance, and has no side effect on a human body. Continued food conditioning and exercise can normalize fatty liver. The product has the advantages of no need of taking medicine, no injection, no increase in price, and is basically the same as common flour. The fatty liver-free food can also be used as a defensive health product, and can be made into steamed mold, noodles, dumpling, steamed roll, oil tea, etc.
In order to improve the content of dietary fiber, the traditional method for manufacturing resistant starch usually adopts heating starch to gelatinize the starch and rapidly cooling the starch to age gelatinized liquid, and as one-time processing usually hardly meets the requirement of the content of the dietary fiber, the requirement can be met by repeatedly processing for several times, the production process is too complex, and simultaneously the content of the dietary fiber still hardly meets the application requirement in high-end products.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a preparation method of resistant starch.
The technical scheme of the invention is as follows:
a preparation method of resistant starch comprises the following steps:
(1) preparing starch milk, adjusting the pH value to 4.0-6.0, heating to 50-80 ℃, adding pullulanase according to the weight percentage of 0.02-0.2 percent of dry starch base, and reacting for 0.5-2 hours to prepare reaction liquid;
(2) deactivating enzyme of the reaction liquid prepared in the step (1), adding resistant dextrin according to the proportion of 20-40% (weight percentage) of dry starch basis, keeping the temperature for 2-12 h under the stirring condition of 100-150 ℃, and cooling to prepare resistant starch slurry;
(3) and (3) centrifuging the resistant starch slurry prepared in the step (2) to obtain a precipitate, thus preparing the resistant starch.
Preferably, in the step (1), the starch is corn starch, wheat starch, rice starch, tapioca starch, potato starch and/or sweet potato starch.
Further preferably, in the step (1), the starch is high amylose corn starch.
According to the invention, in the step (1), the mass concentration of the starch milk is 10-30%, and the pH value is 5.0-6.0.
According to the invention, in the step (2), the enzyme deactivation condition is 120-150 ℃, and the temperature is kept for 2-5 min.
Preferably, in step (2), the cooling is performed to room temperature.
According to the invention, in the step (3), the centrifugation is performed for 5-30 min under the condition of 1000-1500 r/min.
According to the present invention, after the centrifugation in step (3), a step of water washing treatment and/or drying and pulverizing treatment is further included.
According to the invention, the water washing treatment is to wash and centrifuge the precipitate for three times, and then add water to prepare the resistant starch.
According to the invention, the drying and crushing treatment is further preferable, and the resistant starch powder is prepared by drying, crushing and sieving the precipitate.
Advantageous effects
The inventor of the invention firstly discovers that the fiber content in the resistant starch can be obviously improved after the starch is treated as the raw material and is mixed with the resistant dextrin and reacts under specific conditions, so that the fiber content reaches more than 50 percent, the problem that the fiber content is still insufficient after repeated processing for many times in the prior art is solved, and simultaneously, all indexes of the produced resistant starch are obviously improved, and the application requirements of high-end products can be met.
Detailed Description
In order to better illustrate the technical solution of the present invention, the present invention is further described below by way of examples, but the scope of the present invention is not limited thereto.
Source of raw materials
The pullulanase described in the examples was purchased from novacin;
high amylose corn starch was purchased from Shandonghua agricultural specialty corn development Co., Ltd;
the resistant dextrin is purchased from bioscience and technology corporation of Bailong Chuang, Shandong; the detection shows that the content of dietary fiber is more than or equal to 85 percent.
Example 1
A preparation method of resistant starch comprises the following steps:
(1) preparing corn starch milk with the mass concentration of 10% and the pH value of 5.0, heating to 50 ℃, adding pullulanase according to the proportion of 0.02% (weight percentage) of the dry starch basis, and reacting for 2 hours to obtain a reaction solution;
(2) preserving the temperature of the reaction solution prepared in the step (1) for 5min at 120 ℃ to inactivate enzyme, then adding resistant dextrin according to the proportion of 20 percent (weight percentage) of the dry basis of the starch, preserving the temperature for 12h under the stirring condition of 100 ℃, and cooling to room temperature to prepare resistant starch slurry;
(3) centrifuging the resistant starch slurry prepared in the step (2) for 30min at the speed of 1000r/min, taking the precipitate, and then performing water washing treatment, drying and crushing treatment to prepare the resistant starch;
the water washing treatment is to wash and centrifuge the precipitate for three times and add water to prepare resistant starch;
the drying and crushing treatment is to prepare resistant starch powder after drying, crushing and sieving the precipitate, and the content of dietary fiber is 51.21% by detection.
Example 2
A preparation method of resistant starch comprises the following steps:
(1) preparing corn starch milk with the mass concentration of 25% and the pH value of 5.5, heating to 60 ℃, adding pullulanase according to the proportion of 0.1% (weight percentage) of the dry starch basis, and reacting for 1.2h to prepare reaction liquid;
(2) preserving the temperature of the reaction solution prepared in the step (1) for 3min at 130 ℃ to inactivate the enzyme, then adding resistant dextrin according to the proportion of 30 percent (weight percentage) of the dry basis of the starch, preserving the temperature for 8h under the stirring condition of 130 ℃, and cooling to room temperature to prepare resistant starch slurry;
(3) centrifuging the resistant starch slurry prepared in the step (2) for 15min at the speed of 1200r/min, taking the precipitate, and then performing water washing treatment, drying and crushing treatment to prepare the resistant starch;
the water washing treatment is to wash and centrifuge the precipitate for three times and add water to prepare resistant starch;
the drying and crushing treatment is to prepare resistant starch powder after drying, crushing and sieving the precipitate, and the content of dietary fiber is 51.55% by detection.
Example 3
A preparation method of resistant starch comprises the following steps:
(1) preparing corn starch milk with the mass concentration of 30% and the pH value of 6.0, heating to 80 ℃, adding pullulanase according to the proportion of 0.2% (weight percentage) of the dry starch basis, and reacting for 0.5h to prepare a reaction solution;
(2) preserving the temperature of the reaction solution prepared in the step (1) at 150 ℃ for 2min to inactivate the enzyme, then adding resistant dextrin according to the proportion of 40 percent (weight percentage) of the dry starch basis, preserving the temperature for 2h under the stirring condition of 150 ℃, and cooling to room temperature to prepare resistant starch slurry;
(3) centrifuging the resistant starch slurry prepared in the step (2) for 5min at 1500r/min, taking the precipitate, and then performing water washing treatment, drying and crushing treatment to prepare the resistant starch;
the water washing treatment is to wash and centrifuge the precipitate for three times and add water to prepare resistant starch;
the drying and crushing treatment is to prepare resistant starch powder after drying, crushing and sieving the precipitate, and the content of dietary fiber is 51.15% by detection.
Comparative example 1
A preparation method of resistant starch comprises the following steps:
(1) preparing corn starch milk with the mass concentration of 25% and the pH value of 5.5, heating to 60 ℃, adding pullulanase according to the proportion of 0.1% (weight percentage) of the dry starch basis, and reacting for 1.2h to prepare reaction liquid;
(2) preserving the temperature of the reaction solution prepared in the step (1) at 130 ℃ for 3min to inactivate enzyme, cooling to room temperature, and adding resistant dextrin according to the proportion of 30 percent (by weight) of the dry basis of the starch to prepare resistant starch slurry;
(3) centrifuging the resistant starch slurry prepared in the step (2) for 15min at the speed of 1000r/min, taking the precipitate, and then performing water washing treatment, drying and crushing treatment to obtain a product;
the water washing treatment is to wash and centrifuge the precipitate for three times and add water to prepare resistant starch;
the drying and crushing treatment is to prepare resistant starch powder after drying, crushing and sieving the precipitate,
the content of dietary fiber is 32.36 percent by detection.
Comparative example 2
A preparation method of resistant starch comprises the following steps:
(1) preparing corn starch milk with the mass concentration of 30% and the pH value of 6.0, heating to 80 ℃, adding pullulanase according to the proportion of 0.2% (weight percentage) of the dry starch basis, and reacting for 0.5h to prepare a reaction solution;
(2) preserving the temperature of the gelatinized starch milk prepared in the step (1) for 2min at 150 ℃ to inactivate enzyme, then adding resistant dextrin according to the proportion of 60 percent (weight percentage) of the dry basis of the starch, preserving the temperature for 2h under the stirring condition of 150 ℃, and cooling to room temperature to prepare resistant starch slurry;
(3) centrifuging the resistant starch slurry prepared in the step (2) for 5min at 1500r/min, taking the precipitate, and then performing water washing treatment, drying and crushing treatment to prepare the resistant starch;
the washing treatment is to wash and centrifuge the precipitate for three times, and then add water to prepare colorless resistant starch;
the drying and crushing treatment is to prepare colorless resistant starch powder after drying, crushing and sieving the precipitate, and the content of dietary fiber is detected to be 50.17%.
Analysis of results
The comparison shows that the content of the dietary fiber in the examples 1, 2 and 3 reaches more than 50% by adding the resistant starch and subsequent treatment, the content of the dietary fiber in the comparative example 1 only reaches 32.36% because the heat preservation reaction after adding the resistant starch is not carried out, the difference is very obvious, and the content of the dietary fiber in the comparative example 2 reaches more than 50%, but the production cost is increased by about 25% compared with the example 2.