Rapid rehydration type recombinant rice with high phenolic acid bioavailability and preparation method thereof

Abstract

The invention discloses rapid rehydration type recombinant rice with high phenolic acid bioavailability and a preparation method thereof, and the preparation method comprises the following steps: S1, uniformly mixing indica rice flour, sweet potato stem and leaf powder and a pore-foaming agent to obtain a rice flour mixture; s2, extruding the rice flour mixture by adopting a twin-screw extruder to prepare recombinant rice; s3, drying and cooling the recombinant rice to obtain the rapid rehydration type recombinant rice with high phenolic acid bioavailability. The sweet potato stems and leaves rich in phenolic acid are added into the rice flour, and the water-soluble pore-foaming agent is introduced to promote the formation of a microporous structure of the recombinant rice, so that not only can rapid rehydration be realized and the eating convenience be improved, but also the cumulative release amount and the bioavailability of the phenolic acid are improved.

Description

Technical Field

[0001] The invention relates to the technical field of grain processing, and in particular to a fast-rehydrating type high-phenolic acid bioavailability recombinant rice and a preparation method thereof. Background Art

[0002] Extruded reconstituted rice technology is to process rice and other raw materials through stirring, mixing, heating, and extrusion, and develop nutritious and personalized rice products based on the optimal combination of target nutrient raw materials. It is an effective way to develop nutritious rice products. Studies have shown that after extrusion treatment, the starch gelatinization degree of rice is higher, the soluble dietary fiber content is increased, the fiber water holding capacity and swelling capacity are improved, and the physiological activity of rice is enhanced; the extrusion puffing technology is used to prepare nutritious reconstituted rice with added Poria cocos, and the hydrolysis index and glycemic index of the product starch are significantly reduced.

[0003] Caffeoylquinic acid (CQA) is a common polyphenol compound in plants and is widely found in fruits and vegetables. It is formed by the esterification reaction of cinnamic acid, caffeic acid and l-quinic acid. It usually exists in the form of mono (CQA), di (diCQA) and tri-substituted (tri-CQA). It has antioxidant, antibacterial, antiparasitic, anti-inflammatory, anticancer, antiviral and hypoglycemic biological activities. However, its low bioavailability and the instability of its structure and activity in acid, heat and metal ion environments have greatly limited its application in food.

[0004] Although extrusion puffing technology can integrate staple food with nutritionally active ingredients to achieve the production of nutritionally fortified recombinant rice, due to the relatively dense gel structure formed by recombinant rice, it often requires further steaming to be fully cooked when eaten, which is not convenient and fast enough. In addition, the release of nutritionally active components is also limited during the digestion stage of recombinant rice.

[0005] Therefore, it is particularly important to solve the problem of low bioavailability of nutritionally active components of recombinant rice on the basis of improving the rapid rehydration and ripening of recombinant rice. Summary of the invention

[0006] In view of this, the purpose of the present invention is to add sweet potato stems and leaves rich in phenolic acid to rice flour, and introduce a water-soluble pore-forming agent to promote the formation of a multi-microporous structure of the recombinant rice, so as to achieve rapid rehydration and improve its edible convenience, and also improve the cumulative release amount and bioavailability of phenolic acid, and provide a rapid rehydration type high phenolic acid bioavailability recombinant rice and a preparation method thereof. The recombinant rice has a short rehydration time, good taste quality, high phenolic acid release amount and bioavailability after digestion, and obvious advantages in edible convenience and nutritional activity.

[0007] In order to achieve the above technical objectives, this application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a method for preparing a rapidly rehydrated recombinant rice with high phenolic acid bioavailability, comprising the following steps:

[0009] S1. The indica rice flour, sweet potato stem and leaf powder, and the pore-forming agent are mixed to obtain a rice flour mixture;

[0010] S2. The rice flour mixture is extruded using a twin-screw extruder to prepare recombinant rice;

[0011] S3. The recombinant rice is dried and cooled to obtain the fast rehydration type high phenolic acid bioavailability recombinant rice.

[0012] Preferably, in step S1, the water content of the indica rice flour is 28wt%-40wt%.

[0013] Preferably, in step S1, the weight proportions of the raw materials are: 84-94 weight proportions of indica rice flour, 5-15 weight proportions of sweet potato stem and leaf powder, and 0.5-2 weight proportions of porogen.

[0014] Preferably, in step S1, the porogen is hydroxypropyl methylcellulose, polyethylene glycol or a mixture of both.

[0015] Preferably, the porogen is a mixture of hydroxypropyl methylcellulose and polyethylene glycol.

[0016] More preferably, the weight parts of each raw material are: 89 weight parts of indica rice flour, 10 weight parts of sweet potato stem and leaf powder, 0.7 weight parts of hydroxypropyl methylcellulose, and 0.3 weight parts of polyethylene glycol.

[0017] Preferably, in step S2, the specific extrusion process parameters of the twin-screw extruder are: feed rate is 18kg / h, screw speed is 20Hz, cutter speed is 30Hz, and the heating temperatures of the three-section cavities are 50°C in zone I, 80°C in zone II, and 100°C in zone III, respectively.

[0018] Preferably, in step S3, the drying temperature is 40° C., and the mixture is dried for 6 hours and then naturally cooled.

[0019] In a second aspect, the present application provides a rapidly reconstituted high phenolic acid bioavailability recombinant rice prepared by the above-mentioned method.

[0020] The beneficial effects of this application are as follows:

[0021] The porogen added in the preparation of the recombinant rice is a water-soluble molecule, and extrusion promotes the formation of a multi-microporous structure of the recombinant rice. When the recombinant rice is brewed with boiling water, the porogen is partially dissolved to produce an in-situ pore-forming effect, and more water enters the recombinant rice through the micropores, so that rapid rehydration can be achieved, thereby improving its convenience in consumption.

[0022] The sweet potato stem and leaf powder added in the preparation of the recombinant rice of the present invention is rich in phenolic acids such as caffeoylquinic acid (CQA), chlorogenic acid, caffeic acid and the like with different degrees of substitution, and has biological activities such as anti-oxidation, anti-inflammatory and hypoglycemic. After digestion by the gastrointestinal tract, the porogen is partially dissolved to form tiny water-soluble pores, which, on the one hand, promote the release of phenolic acid and increase the cumulative release amount of phenolic acid. On the other hand, water penetrates through the micropores, prompting the phenolic acid to dissolve into a saturated solution and release it at a stable rate, thereby achieving the effect of sustained or controlled release of phenolic acid, significantly improving the bioavailability of phenolic acid and giving the recombinant rice better health effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 HPLC chromatogram of phenolic acids in sweet potato stem and leaf powder. DETAILED DESCRIPTION

[0024] The invention discloses a fast rehydration type high phenolic acid bioavailability recombinant rice and a preparation method thereof, comprising the following steps: S1. uniformly mixing indica rice flour, sweet potato stem and leaf powder, and a pore-forming agent to obtain a rice flour mixture; S2. extruding the rice flour mixture with a twin-screw extruder to prepare recombinant rice; S3. drying and cooling the recombinant rice to obtain the fast rehydration type high phenolic acid bioavailability recombinant rice. The invention adds sweet potato stems and leaves rich in phenolic acid to rice flour, and introduces a water-soluble pore-forming agent to promote the formation of a multi-microporous structure of the recombinant rice, which can not only achieve fast rehydration and improve its edible convenience, but also increase the cumulative release amount and bioavailability of phenolic acid.

[0025] The present invention is further described in detail below through implementation cases.

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0028] The sources of the indica rice flour used in the following examples are as follows: commercially available indica rice is crushed using a crusher, the crushing temperature is controlled to be ≤50° C., and passed through an 80-mesh sieve to obtain indica rice flour.

[0029] The source of the sweet potato stem and leaf powder used in the following embodiments is as follows: commercially available sweet potato leaves are washed and dried in a hot air dryer at a drying temperature of ≤60°C, then crushed in a crusher at a crushing temperature of ≤50°C, and passed through an 80-mesh sieve to obtain the sweet potato stem and leaf powder.

[0030] The source of the hydroxypropyl methylcellulose used in the following examples is as follows: hydroxypropyl methylcellulose, CAS No.: 9004-65-3, food grade.

[0031] The sources of polyethylene glycol used in the following examples are as follows: polyethylene glycol 6000, CAS No.: 25322-68-3, average molecular weight 5400-7800, food grade.

[0032] Example 1

[0033] This embodiment provides a method for preparing a rapidly rehydrated recombinant rice with high phenolic acid bioavailability, comprising the following steps:

[0034] S1. Adjust the moisture content of indica rice flour to 28wt%, then 84 parts by mass of indica rice flour, 15 parts by mass of sweet potato stem powder, 1 part by mass of hydroxypropyl methylcellulose and 1 part by mass of polyethylene glycol were mixed to obtain a rice flour mixture;

[0035] S2. The rice flour mixture was extruded by a twin-screw extruder, and the specific extrusion process parameters were: a feed rate of 18kg / h, a screw speed of 20Hz, a cutter speed of 30Hz, and the heating temperatures of the three chambers were 50 ° C in zone Ⅰ, 80 ° C in zone Ⅱ, and 100 ° C in zone Ⅲ to prepare recombinant rice;

[0036] S3. The recombinant rice is dried at a temperature of 40° C. for 6 hours and then naturally cooled.

[0037] Example 2

[0038] This embodiment provides a method for preparing a rapidly rehydrated recombinant rice with high phenolic acid bioavailability, comprising the following steps:

[0039] S1. Adjust the moisture content of indica rice flour to 34wt%, then 89 parts by mass of indica rice flour, 10 parts by mass of sweet potato stems and leaves powder, 0.7 parts by mass of hydroxypropyl methylcellulose and 0.3 parts by mass of polyethylene glycol were mixed to obtain a rice flour mixture;

[0040] S2. The rice flour mixture was extruded by a twin-screw extruder, and the specific extrusion process parameters were: a feed rate of 18kg / h, a screw speed of 20Hz, a cutter speed of 30Hz, and the heating temperatures of the three chambers were 50 ° C in zone Ⅰ, 80 ° C in zone Ⅱ, and 100 ° C in zone Ⅲ to prepare recombinant rice;

[0041] S3. The recombinant rice is dried at a temperature of 40° C. for 6 hours and then naturally cooled.

[0042] Example 3

[0043] This embodiment provides a method for preparing a rapidly rehydrated recombinant rice with high phenolic acid bioavailability, comprising the following steps:

[0044] S1. Adjust the moisture content of indica rice flour to 40wt%, then 95 parts by mass of indica rice flour, 5 parts by mass of sweet potato stems and leaves powder, 0.35 parts by mass of hydroxypropyl methylcellulose and 0.15 parts by mass of polyethylene glycol were mixed to obtain a rice flour mixture;

[0045] S2. The rice flour mixture was extruded by a twin-screw extruder, and the specific extrusion process parameters were: a feed rate of 18kg / h, a screw speed of 20Hz, a cutter speed of 30Hz, and the heating temperatures of the three chambers were 50 ° C in zone Ⅰ, 80 ° C in zone Ⅱ, and 100 ° C in zone Ⅲ to prepare recombinant rice;

[0046] S3. The recombinant rice is dried at a temperature of 40° C. for 6 hours and then naturally cooled.

[0047] Comparative Example 1

[0048] The moisture content of the indica rice flour was adjusted to 25 wt %, and other conditions were the same as those in Example 2.

[0049] Comparative Example 2

[0050] The moisture content of the indica rice flour was adjusted to 42wt%, and other conditions were the same as in Example 2.

[0051] Comparative Example 3

[0052] No sweet potato stem and leaf powder was added to the raw materials, and other conditions were the same as in Example 2.

[0053] Comparative Example 4

[0054] The sweet potato stem and leaf powder in the raw material is 2 parts by mass, and other conditions are the same as those in Example 2.

[0055] Comparative Example 5

[0056] The sweet potato stem and leaf powder in the raw material is 20 parts by mass, and other conditions are the same as those in Example 2.

[0057] Comparative Example 6

[0058] No porogen was added to the raw materials, and other conditions were the same as those in Example 2.

[0059] Comparative Example 7

[0060] The raw materials contained 0.1 parts by mass of hydroxypropyl methylcellulose and 0.1 parts by mass of polyethylene glycol, and other conditions were the same as those in Example 2.

[0061] Comparative Example 8

[0062] The raw materials include 2 parts by mass of hydroxypropyl methylcellulose and 2 parts by mass of polyethylene glycol, and other conditions are the same as those in Example 2.

[0063] Comparative Example 9

[0064] The amount of hydroxypropyl methylcellulose in the raw material was 1.0 parts by mass, and other conditions were the same as those in Example 2.

[0065] Comparative Example 10

[0066] The raw material contains 1.0 parts by mass of polyethylene glycol, and other conditions are the same as those in Example 2.

[0067] Evaluation Test

[0068] The sensory evaluation method was used to characterize the morphology and color uniformity of the recombinant rice, and the whole rice was selected and the whole rice rate was calculated.

[0069] Table 1 Effects of different moisture contents of indica rice flour on sensory quality and whole rice rate of recombinant rice

[0070]

[0071] As shown in Table 1, the moisture content of indica rice flour has a significant effect on the grain morphology and color uniformity of recombinant rice. Adjusting the moisture content of indica rice flour to 28-40wt% is conducive to maintaining the appearance of recombinant rice. Too high or too low moisture content will make the rice grain morphology incomplete, with obvious adhesion, uneven color, and reduced whole rice rate. When the moisture content of indica rice flour is adjusted to 34wt%, the sensory quality of recombinant rice is the best.

[0072] The composition of phenolic acid in raw materials and recombinant rice after extrusion was determined by high performance liquid chromatography peak, and the phenolic acid content was measured with reference to the standard product to study the effect of sweet potato stem and leaf addition on the retention rate of phenolic acid in recombinant rice. The determination method is as follows:

[0073] Phenolic acid extraction of samples: weigh 0.5 g of sample, mix it evenly with 70% ethanol at a solid-liquid ratio of 1:40 (g / mL), and extract it by ultrasonic at 45 kHz, 500 W, 50°C for 30 min. Repeat twice. After mixing evenly, centrifuge it at 5000 r / min for 10 min, collect the supernatant, and concentrate it by rotary evaporation at 40°C. The extract should be stored at -18°C in the dark.

[0074] Phenolic acid determination method: Waters 2695 high performance liquid chromatography system, C18 column (150mm×4.6mm, 5μm), column temperature 25℃, detection wavelength: 200~400nm; phase A: 0.1% formic acid solution; phase B: acetonitrile solution; elution program: 0~12min, 95~80%A; 12~25min, 80~65%A; 25~35min, 65~95%A; flow rate 0.8mL / min; injection volume 10μL. Refer to the high performance liquid chromatography of phenolic acids in sweet potato stem and leaf powder ( Figure 1 ), compared with the standard, and calculated the phenolic acid content in the sample according to the external standard method.

[0075] Phenolic acid extrusion retention rate (%) = phenolic acid content in recombinant rice / phenolic acid content in raw materials * 100.

[0076] Figure 1 The HPLC chromatogram of phenolic acids in sweet potato stem and leaf powder is shown. Compared with the standard, the phenolic acids corresponding to peaks 1-12 are 5-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, caffeic acid, quercetin 3-O-rutinoside, 3,4-disubstituted caffeoylquinic acid, 3,4-disubstituted caffeoylquinic acid, quinic acid, 4,5-disubstituted caffeoylquinic acid, 3-O-caffeoyl-4-O-sinapoylquinic acid, quercetin, and 3,4,5-trisubstituted caffeoylquinic acid. According to the external standard method, the total phenolic acid content in sweet potato stem and leaf powder is 25.8 mg / g.

[0077] Table 2 Effect of sweet potato stem and leaf addition on the retention rate of recombinant rice phenolic acid

[0078]

[0079] As shown in Table 2, since phenolic acid is unstable to heat, the phenolic acid in the sweet potato stems and leaves is significantly lost during the extrusion process. When 5-15 parts by weight of sweet potato stem and leaf powder is added, the retention rate of phenolic acid in the recombinant rice can reach more than 60%. When the addition amount of sweet potato stem and leaf powder is less than 5 parts by weight or more than 15 parts by weight, the retention rate of phenolic acid in the recombinant rice is significantly reduced. Among them, the recombinant rice prepared with an addition amount of 10 parts by weight of sweet potato stem and leaf powder in Example 2 has the highest phenolic acid retention rate, which is the optimal addition amount.

[0080] The effect of pore-forming agents on the rehydration quality of recombinant rice was studied by measuring the rehydration time and cooking loss rate of recombinant rice. The in vitro gastrointestinal digestion model was used to measure the cumulative release, bioavailability and time required to reach the maximum release of phenolic acid in sweet potato stems and leaves after 5g of recombinant rice was brewed and digested for 3h in the gastrointestinal tract to study the effect of pore-forming agents on the release and bioavailability of phenolic acid in recombinant rice. The specific methods are as follows:

[0081] Method for determining rehydration time: Take an appropriate amount of reconstituted rice, add boiling water and start timing. Take out 10-20 rice samples every 15 seconds, flatten the rice samples with two transparent glass plates, observe whether there is a white core, and record the time when the white core completely disappears, which is the rehydration time of the reconstituted rice.

[0082] Method for determining the cooking loss rate: Take an appropriate amount of recombinant rice M0, determine the dry matter weight M1, add boiling water to brew at the above rehydration time, then filter out the water, and dry at 105°C to constant weight to obtain the dry matter mass M2 after cooking. Calculate the cooking loss rate according to the following formula: Cooking loss rate (%) = (M1-M2) / M0*100.

[0083] Determination method of phenolic acid cumulative release, bioavailability and time required to reach maximum release: weigh 5g recombinant rice sample into a centrifuge tube, add 100mL of 0.1mol / L sodium acetate buffer, gelatinize in boiling water bath for 20min, add α-amylase and saccharifying enzyme solution after the sample cools to room temperature, and place in 37℃ water bath for 180min. Take 2mL of sample every 30min, add 8mL of 95% ethanol to inactivate enzyme, centrifuge at 6000r / min for 10min, concentrate the supernatant to 1mL, and use the above phenolic acid detection method to determine the phenolic acid content in the digestive juice, which is recorded as M and M respectively. 30 、M 60 、M 90 、M 120 、M 150 、M 180 Cumulative release of phenolic acid: The phenolic acid content in the digestive fluid after 180 minutes of digestion is the cumulative release of phenolic acid in the sample, calculated according to the following formula: Cumulative release of phenolic acid = M 30 +M 60 +M 90 +M 120 +M 150 +M 180 ; Phenolic acid bioavailability: the ratio of phenolic acid released after 180 min of digestion to the phenolic acid content of the sample is calculated according to the following formula: phenolic acid bioavailability (%) = cumulative phenolic acid release / phenolic acid content of recombinant rice*100; Time required to reach the maximum phenolic acid release: a kinetic curve is drawn with digestion time as the horizontal axis and phenolic acid release as the vertical axis. The time corresponding to the maximum value of the vertical axis of the curve is the time required to reach the maximum phenolic acid release.

[0084] Table 2 Effects of pore formers on rehydration quality and phenolic acid release of reconstituted rice

[0085]

[0086]

[0087] As shown in Table 2, the addition of pore-forming agent significantly reduced the rehydration and aging time of recombinant rice, and significantly increased the cumulative release amount and bioavailability of phenolic acid in recombinant rice, significantly prolonged the time required to reach the maximum phenolic acid release, and achieved a sustained release effect. Compared with the single use of hydroxypropyl methylcellulose or polyethylene glycol, the simultaneous use of two pore-forming agents had a synergistic improvement effect. However, excessive addition of pore-forming agent significantly increased the cooking loss rate of recombinant rice and accelerated the time required to reach the maximum phenolic acid release, and could not achieve a sustained release effect. In summary, the embodiment had the best effect. 0.7 parts by mass of hydroxypropyl methylcellulose and 0.3 parts by mass of polyethylene glycol were added, and the two exerted a synergistic improvement effect, which not only made the recombinant rice quickly rehydrated, with a low cooking loss rate, and improved its convenience for consumption, but also significantly increased the cumulative release amount and bioavailability of phenolic acid through gastrointestinal digestion.

[0088] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a rapidly rehydrating recombinant rice with high phenolic acid bioavailability, characterized in that: The following steps are involved: S1. The indica rice flour, sweet potato stem and leaf powder, and the pore-forming agent are mixed to obtain a rice flour mixture; S2. The rice flour mixture is extruded using a twin-screw extruder to prepare recombinant rice; S3. The recombinant rice is dried and cooled to obtain the fast rehydration type high phenolic acid bioavailability recombinant rice.

2. The preparation method according to claim 1, characterized in that: In step S1, the water content of the indica rice flour is 28wt%-40wt%.

3. The preparation method according to claim 1, characterized in that: In step S1, the weight proportions of the raw materials are: 84-94 weight proportions of indica rice flour, 5-15 weight proportions of sweet potato stem and leaf powder, and 0.5-2 weight proportions of pore-forming agent.

4. The preparation method according to claim 3, characterized in that: In step S1, the porogen is hydroxypropyl methylcellulose, polyethylene glycol or a mixture of the two.

5. The preparation method according to claim 4, characterized in that: The porogen is a mixture of hydroxypropyl methylcellulose and polyethylene glycol.

6. The preparation method according to claim 5, characterized in that: The weight parts of each raw material are: 89 weight parts of indica rice flour, 10 weight parts of sweet potato stem and leaf powder, 0.7 weight parts of hydroxypropyl methylcellulose, and 0.3 weight parts of polyethylene glycol.

7. The preparation method according to claim 1, characterized in that: In step S2, the specific extrusion process parameters of the twin-screw extruder are: feed rate is 18kg / h, screw speed is 20Hz, cutter speed is 30Hz, and the heating temperatures of the three-section cavities are 50°C in zone I, 80°C in zone II, and 100°C in zone III.

8. The preparation method according to claim 1, characterized in that: In step S3, the drying temperature is 40° C., and the mixture is dried for 6 hours and then cooled naturally.

9. Rapidly rehydrating high phenolic acid bioavailability recombinant rice prepared by the preparation method according to any one of claims 1 to 8.

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