A method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste

Abstract

The invention belongs to the technical field of food processing, and discloses a method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu from fruit processing waste, wherein the method utilizes ultrasound / microwave / pulsed electric field-assisted ethanol extraction of fruit processing waste to obtain polyphenols, and then prepares pigeon blood tofu through high-pressure homogenization wall breaking technology and TG enzyme cross-linking technology, and utilizes the Maillard reaction between sugars contained in the polyphenol extract and pigeon blood protein to improve the antioxidant property of pigeon blood tofu, and the obtained pigeon blood tofu has a compact texture, is elastic, has a bright color, has good water retention, and also has a fruity flavor, better flavor, and is easier to absorb, and has a shelf life of up to 60 days in a 4°C refrigerator, and a longer shelf life. At the same time, the wall breaking technology significantly increases the content of free hemoglobin and free heme iron in the tofu, making it easier to be absorbed by the human body.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu by utilizing fruit processing waste. Background Art

[0002] China is a major fruit producer. At present, fruits are mainly sold fresh and processed in the primary process. Among them, the primary processing will produce a large amount of waste - peels, such as grape peels, dragon fruit peels, mangosteen peels, etc. These peels are rich in polyphenols, which have good medical and health care effects because of their strong antioxidant properties. However, the utilization rate of these peels is generally very low, and most of them are treated as garbage, which not only causes serious environmental pollution, but also causes huge waste of resources. The utilization efficiency of the few peels that are not treated as garbage is also low. Solvent extraction is often used to extract peel polyphenols. Although the operation is simple, it is time-consuming and the extraction efficiency is low. Other single extraction methods, such as pulsed electric field and ultrasound, also have limited improvement in extraction efficiency. High-value utilization of these processing wastes and improving the utilization rate are the key to solving such environmental pollution and resource waste, and are also the guarantee for the healthy and rapid development of the fruit processing industry.

[0003] Pigeon blood is a resource with high nutritional value, known as "liquid meat". It is rich in protein and trace elements (such as iron), as well as appropriate amounts of minerals, vitamins, hormones, enzymes and other physiologically active substances. These components are stable in content and have the effects of regulating blood sugar and enhancing immunity. However, pigeon blood is often directly discarded as meat pigeon processing waste, which not only greatly wastes precious food resources, but also pollutes the environment. Making full use of pigeon blood resources can not only solve the problem of environmental pollution caused by slaughtering pigeon blood waste, but also help to improve the economic value of pigeons. At present, there are many studies on the processing and utilization of poultry blood at home and abroad, but there are few studies on the processing and utilization of pigeon blood and pigeon blood and fruit processing waste. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste. The method uses ultrasonic / microwave / pulsed electric field-assisted ethanol extraction of fruit processing waste to obtain polyphenols, and then prepares pigeon blood tofu through high-pressure homogenization wall breaking technology and TG enzyme cross-linking technology, and utilizes the sugars contained in the polyphenol extract to react with pigeon blood protein to produce Maillard reaction, thereby improving the antioxidant property of pigeon blood tofu. The obtained pigeon blood tofu also has a fruity flavor and better flavor. At the same time, the wall breaking technology significantly increases the content of free hemoglobin and free heme iron in tofu, making it easier to be absorbed by the human body.

[0005] To achieve the purpose of the present invention, the method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste comprises the following steps:

[0006] (1) Preparation of polyphenol concentrate: crushing and homogenizing fruit processing waste to obtain pulp, mixing the pulp with an ethanol solution, subjecting the mixture to ultrasonic / microwave treatment, and then subjecting the mixture to a pulsed electric field treatment to obtain a polyphenol crude extract, which is then evaporated and concentrated in a rotary evaporator to obtain a concentrate;

[0007] (2) Pigeon blood collection: Collect fresh pigeon blood, add anticoagulant to it, mix well and filter;

[0008] (3) breaking the pigeon blood wall: subjecting the pigeon blood obtained by filtration in step (2) to high pressure homogenization to obtain pigeon blood after the wall is broken;

[0009] (4) Cross-linking and coagulation of pigeon blood: sodium chloride, alanine aminotransferase (TGase) and the polyphenol concentrate obtained in step (1) are added to the pigeon blood after the cell wall is broken in step (3), and the mixture is kept warm at 40-45° C., and calcium sulfate is added after the warm treatment and mixed evenly;

[0010] (5) Sterilizing pigeon blood tofu: sterilize the pigeon blood tofu obtained in step (3) at 85-90° C. for 40-50 min, and cool to obtain pigeon blood tofu.

[0011] Furthermore, in some embodiments of the present invention, the fruit processing waste includes but is not limited to grape skins, dragon fruit skins, mangosteen skins, etc.

[0012] Furthermore, in some embodiments of the present invention, the ethanol extraction conditions in step (1) are: the slurry volume ratio is 1:1 to 3:1; preferably, the ethanol volume fraction is 30% to 50%.

[0013] Preferably, in some embodiments of the present invention, in step (1), the ultrasonic / microwave treatment parameters are: ultrasonic power 100-400 W, frequency 18-20 kHz, ultrasonic time 2s-8s, interval time 2s-8s, microwave power 100-300 W, time 2-5 min.

[0014] Furthermore, in some embodiments of the present invention, in step (1), the pulse electric field parameters are: electrode distance is 10-25 cm, pulse intensity is 500-800 V / cm, and pulse period is 1-8 ms.

[0015] Furthermore, in some embodiments of the present invention, in step (1), the evaporation concentration conditions are: temperature 45-50°C, rotation speed 90-110 r / min, extraction temperature 45-50°C, and pH 4.0-5.0.

[0016] Furthermore, in some embodiments of the present invention, in step (2), the anticoagulant is a sodium citrate solution, preferably a sodium citrate solution with a mass percentage of 0.5%; preferably, the volume ratio of the anticoagulant to pigeon blood is 1:0.8-1.5; preferably, the filter screen is 400-800 mesh.

[0017] Furthermore, in some embodiments of the present invention, in step (3), the high-pressure homogenization pressure is 20 to 50 MPa.

[0018] Furthermore, in some embodiments of the present invention, in the step (4), the amount of sodium chloride added is 1 to 1.4% of the mass of the pigeon blood after wall breaking.

[0019] Preferably, in some embodiments of the present invention, in step (4), the amount of polyphenol concentrate added is 1.5-3% of the mass of the pigeon blood after wall breaking.

[0020] Furthermore, in some embodiments of the present invention, in step (4), the amount of TG enzyme added is 0.2% to 0.5% of the mass of pigeon blood; preferably, the reaction pH is 6.5 to 7.5.

[0021] Preferably, in some embodiments of the present invention, in step (4), the heat preservation treatment is performed for 30 to 50 minutes.

[0022] Preferably, in some embodiments of the present invention, in step (4), calcium sulfate is added in an amount of 1 to 3% by volume of pigeon blood.

[0023] Furthermore, in some embodiments of the present invention, in step (5), the sterilization treatment is performed at 85-90° C. for 40-50 min.

[0024] Preferably, in some embodiments of the present invention, in step (5), cooling is performed by cooling in an ice water bath for 40 to 50 minutes.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) The present invention adopts ultrasound / microwave / pulse electric field assisted ethanol extraction of fruit pulp to extract polyphenols, and utilizes the ultrasonic cavitation effect, microwave heating effect and pulse electric field effect to increase the release of polyphenols in the peel, with a fast rate and a high extraction rate;

[0027] (2) The present invention adopts high-pressure homogenization wall-breaking technology combined with TG enzyme cross-linking technology to improve the dissolution of hemoglobin and heme iron, making it easier to be absorbed by the human body;

[0028] (3) The present invention uses polyphenols extracted from peel waste and pigeon blood to prepare pigeon blood tofu, and utilizes the Maillard reaction between sugars contained in the polyphenol extract and pigeon blood protein to improve the antioxidant property of pigeon blood tofu. The obtained pigeon blood tofu has a compact texture, elasticity, bright color, good water retention, fruity flavor, better flavor, easier to absorb, and a shelf life of up to 60 days in a 4°C refrigerator, and a longer shelf life. At the same time, the wall-breaking technology significantly increases the content of free hemoglobin and free heme iron in the tofu, making it easier to be absorbed by the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a comparison of the hemoglobin content of pigeon blood tofu prepared by the traditional process and the process of Example 1 of the present invention;

[0030] Figure 2 It is a comparison of the shelf life of pigeon blood tofu prepared by the traditional process and the process of Example 1 of the present invention;

[0031] Figure 3 It is a comparison of the extraction rate of polyphenols by the conventional process and the extraction process of Example 1 of the present invention;

[0032] Figure 4 The figure is a comparison of the water content of pigeon blood tofu prepared by the traditional process and the process of Example 1 of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Additional aspects and advantages of the present invention will be given in part in the following description, and part will become apparent from the following description, or will be understood through the practice of the present invention. It should be understood that the following description is only used to explain the present invention and is not intended to limit the present invention.

[0034] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0035] When amount, concentration or other value or parameter is expressed as range, preferred range or a series of upper preferred value and lower preferred value limit range, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1 to 5", described range should be interpreted as including range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0036] Singular forms include plural references unless the context clearly indicates otherwise. "Optional" or "either" means that the subsequently described event or incident may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

[0037] The indefinite articles "a" and "an" before the elements or components of the present invention have no limitation on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the quantity obviously refers to the singular form only.

[0038] In addition, the descriptions of the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" described below mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0039] Example 1

[0040] The grape skins, waste from fruit processing, were crushed and homogenized to obtain pulp, and then 200 mL of pulp was mixed with 100 mL of ethanol solution, and the pH was adjusted to 4.5; ultrasonic / microwave treatment was performed for 3 minutes at an ultrasonic power of 200 W, a frequency of 20 kHz, an ultrasonic time of 5 s, an interval of 8 s, and a microwave power of 200 W, and then pulse electric field treatment was performed at an electrode distance of 15 cm, a pulse intensity of 500 V / cm, and a pulse period of 5 ms; the extraction temperature was 45° C., and the polyphenol crude extract was evaporated and concentrated in a rotary evaporator at a rotation speed of 100 r / min at 45° C. to obtain a polyphenol concentrate. Then 300 mL of fresh pigeon blood was collected, 300 mL of 1% sodium citrate solution was added thereto, and the mixture was mixed and filtered through a 600 mesh sieve. Within 20 minutes, it is high-pressure homogenized at a pressure of 40 MPa, and then 1% sodium chloride solution, 0.25% TG enzyme and 2% polyphenol concentrate are added, and the mixture is kept warm at 40°C for 40 minutes. After the heat preservation treatment, 3% calcium sulfate by volume of pigeon blood is added and mixed evenly, and the mixture is sterilized at 85°C for 40 minutes, and cooled in an ice water bath for 40 minutes to obtain pigeon blood tofu.

[0041] Example 2

[0042] The fruit processing waste pitaya peel was crushed and homogenized into pulp, and then 300 mL of pulp was mixed with 150 mL of ethanol solution, and the pH was adjusted to 5.0; ultrasonic / microwave treatment was performed for 4 minutes at an ultrasonic power of 200 W, a frequency of 20 kHz, an ultrasonic time of 3 s, an interval of 5 s, and a microwave power of 100 W, and then pulse electric field treatment was performed at an electrode distance of 20 cm, a pulse intensity of 600 V / cm, and a pulse period of 5 ms; the extraction temperature was 50° C., and the polyphenol crude extract was evaporated and concentrated in a rotary evaporator at a rotation speed of 110 r / min at 45° C. to obtain a polyphenol concentrate. Then 500 mL of fresh pigeon blood was collected, 600 mL of 1% sodium citrate solution was added thereto, and the mixture was mixed and filtered through a 500 mesh sieve. Within 20 minutes, it was high-pressure homogenized at a pressure of 50 MPa, and then 1% sodium chloride solution, 0.35% TG enzyme and 2.5% polyphenol concentrate were added, and the mixture was kept warm at 45°C for 40 minutes. After the heat preservation treatment, 2% calcium sulfate by volume of pigeon blood was added and mixed evenly, and the mixture was sterilized at 90°C for 40 minutes, and cooled in an ice water bath for 40 minutes to obtain pigeon blood tofu.

[0043] Example 3

[0044] The grape skins, waste from fruit processing, were crushed and homogenized to obtain pulp, and then 200 mL of pulp was mixed with 150 mL of ethanol solution, and the pH was adjusted to 5.0; ultrasonic / microwave treatment was performed for 3 min at an ultrasonic power of 100 W, a frequency of 20 kHz, an ultrasonic time of 3 s, an interval of 3 s, and a microwave power of 200 W, and then pulse electric field treatment was performed at an electrode distance of 20 cm, a pulse intensity of 600 V / cm, and a pulse period of 8 ms; the extraction temperature was 50° C., and the polyphenol crude extract was evaporated and concentrated in a rotary evaporator at a rotation speed of 110 r / min at 45° C. to obtain a polyphenol concentrate. Then 400 mL of fresh pigeon blood was collected, 500 mL of 1% sodium citrate solution was added thereto, and the mixture was mixed and filtered through a 600 mesh sieve. Within 25 minutes, it was high-pressure homogenized at a pressure of 30 MPa, and then 1.2% sodium chloride solution, 0.45% TG enzyme and 2.5% polyphenol concentrate were added, and the mixture was kept warm at 40°C for 30 minutes. After the heat preservation treatment, 2% calcium sulfate by volume of pigeon blood was added and mixed evenly, and the mixture was sterilized at 85°C for 50 minutes, and cooled in an ice water bath for 50 minutes to obtain pigeon blood tofu.

[0045] Comparative example: Traditional craft

[0046] Filter fresh pigeon blood, weigh clean cold water at 1 times the amount of plasma, take half of the total water, add 2-3% edible salt and stir to dissolve. Add pigeon blood to coagulate into blood clots, and boil in 80 hot water for 30-40 minutes.

[0047] Table 1-2 shows the effects of the traditional process and the process of Example 2 of the present invention on the texture of pigeon blood tofu, as well as a comparison of the antioxidant properties of the pigeon blood tofu prepared by the traditional process and the process of Example 2 of the present invention. From the comparison results, it can be seen that the pigeon blood tofu obtained by Example 2 of the present invention has significantly better performance in all aspects than the pigeon blood tofu obtained by the traditional process.

[0048] Table 1 Effect of different processes on the texture of pigeon blood tofu (measured by texture analyzer)

[0049] Technology Hardness(g) Adhesiveness elasticity Stickiness Chewability Traditional crafts 682±34 -29.36±2.75 0.88±0.02 534±28 523±17 Process of the present invention 893±52 -38.27±1.91 0.95±0.01 794±19 839±46

[0050] Table 2 Comparison of antioxidant properties of pigeon blood tofu prepared by different processes

[0051] Technology <![CDATA[Reducing power (Abs 700nm )]]> DPPH clearance rate (%) TEAC (mmol trolox / g) Traditional crafts 0.05±0.01 14.3±1.95 0.53±0.06 Process of the present invention 0.52±0.03 77.8±2.56 10.98±1.14

[0052] Those skilled in the art will easily understand that the above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste, characterized in that: The method comprises the following steps: (1) Preparation of polyphenol concentrate: crush and homogenize fruit processing waste into pulp, mix the pulp with ethanol solution, treat with ultrasonic wave / microwave, and then treat with pulse electric field to obtain polyphenol crude extract, which is then evaporated and concentrated in a rotary evaporator to obtain a concentrate; (2) Pigeon blood collection: Collect fresh pigeon blood, add anticoagulant to it, mix well and filter; (3) Broken pigeon blood: The pigeon blood filtered in step (2) is subjected to high pressure homogenization to obtain broken pigeon blood; (4) Cross-linking and coagulation of pigeon blood: adding sodium chloride, alanine aminotransferase and the polyphenol concentrate obtained in step (1) to the pigeon blood after cell wall breaking in step (3), heat-treating at 40-45° C., and then adding calcium sulfate and mixing evenly; (5) Sterilizing the pigeon blood tofu: sterilize the pigeon blood tofu obtained in step (3) at 85-90° C. for 40-50 min, and cool it to obtain the pigeon blood tofu.

2. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: The fruit processing waste is one or more of grape peels, dragon fruit peels, and mangosteen peels.

3. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: The ethanol extraction conditions in step (1) are: the slurry volume ratio is 1:1-3:1; the ethanol volume fraction is 30%-50%; in step (1), the ultrasonic / microwave treatment parameters are: ultrasonic power 100-400W, frequency 18-20kHz, ultrasonic time 2s-8s, interval time 2s-8s, microwave power 100-300W, time 2-5 min.

4. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: In the step (1), the pulse electric field parameters are: electrode distance is 10 to 25 cm, pulse intensity is 500 to 800 V / cm, and pulse period is 1 to 8 ms.

5. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: In the step (1), the evaporation concentration conditions are: temperature 45-50°C, rotation speed 90-110 r / min, extraction temperature 45-50°C, and pH 4.0-5.

0.

6. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: In the step (2), the anticoagulant is a sodium citrate solution with a mass percentage of 0.5%; the volume ratio of the anticoagulant to pigeon blood is 1:0.8-1.5; and the filter screen is 400-800 mesh.

7. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: In the step (3), the high-pressure homogenization pressure is 20-50 MPa.

8. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: In the step (4), the amount of sodium chloride added is 1-1.4% of the mass of the pigeon blood after cell wall breaking; in the step (4), the amount of polyphenol concentrate added is 1.5-3% of the mass of the pigeon blood after cell wall breaking.

9. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: In the step (4), the amount of TG enzyme added is 0.2% to 0.5% of the mass of pigeon blood; the reaction pH is 6.5 to 7.5; in the step (4), the heat treatment is carried out for 30 to 50 minutes; in the step (4), calcium sulfate is added in an amount of 1 to 3% of the volume of pigeon blood.

10. The method for preparing highly antioxidant and easily absorbable flavored pigeon blood tofu using fruit processing waste according to claim 1, characterized in that: In the step (5), the sterilization treatment is performed at 85-90°C for 40-50 min; in the step (5), the cooling is performed in an ice water bath for 40-50 min.

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