Pear syrup with anti-inflammatory effect and preparation method thereof

Abstract

The invention discloses a preparation method of pear syrup with an anti-inflammatory effect. The preparation method comprises the following steps: performing pretreatment and juicing on pears to obtain pear pulp, performing enzymolysis on the pear pulp by using cellulase and pectinase, performing primary concentration on the obtained pear juice under a vacuum condition, adding reducing sugar into the obtained concentrated pear juice, performing decoction at high temperature and the like. According to the method, low-temperature vacuum concentration is adopted to quickly remove moisture and increase the content of solids, then reducing sugar is added to induce a system to generate a Maillard reaction and a caramelization reaction more quickly, and the high-temperature boiling time is greatly shortened. Compared with a traditional process, 2% of xylose is added into the concentrated pear juice for high-temperature decoction, the polyphenol content, the triterpenoid content and the total flavone content in the prepared pear syrup are obviously increased, the pear syrup prepared by the method has a good anti-inflammatory effect, and the anti-inflammatory effect of the pear syrup can be obviously enhanced by adding the medicinal and edible substances.

Description

Technical Field

[0001] The invention relates to a pear paste with anti-inflammatory effect and a preparation method thereof, belonging to the field of pear paste and preparation thereof. Background Art

[0002] Gaoping rhubarb pear fruit is yellow, large and neat, with a rough, waxy skin and good storage resistance. The flesh is white, juicy and crisp, with moderate sweetness and sourness. Rhubarb pear is rich in flavonoids, phenolic acid compounds, vitamin C and other active substances, making it suitable for preparation into pear paste.

[0003] Pear paste is a traditional medicinal food, made by boiling the juice of pears or pears and other edible ingredients. It has the functions of promoting body fluid, removing phlegm, reducing internal heat, nourishing yin, and stopping coughing and bleeding. Pear paste has a thick semi-fluid nature, and its preparation process involves multiple steps, including juicing, clarifying, filtering, boiling, etc., among which the boiling process has an important influence on its properties and efficacy.

[0004] The traditional method of boiling pear paste takes several hours or even longer. For example, the invention patent CN 110338384A discloses a method for preparing pear paste. The method requires boiling on high heat for 4 hours, then stewing on low heat for 2 hours, until it has a viscous feeling. Although the prepared pear paste has a good taste and color, long-term high-temperature boiling will destroy the active substances such as polyphenols and flavonoids in the system, which will weaken the efficacy of the pear paste and reduce the product quality. The boiling process is actually a concentration process, which removes most of the water and increases the solid content. In order to avoid the degradation of active substances, low-temperature vacuum concentration is used to prepare pear paste. For example, the invention patent CN 10956715 A discloses a Laiyang pear paste and a preparation method thereof. The method uses low-temperature vacuum concentration to obtain Laiyang pear juice of 70°Brix, and then adds fructose, sodium ascorbate and natural edible gum to the concentrated pear juice, and stirs and mixes until it becomes viscous to obtain Laiyang pear paste. Although this type of pear paste also has the viscosity of pear paste and retains a certain fruit flavor and fragrance, this type of pear paste is obtained by adding edible gum, fructose, etc. to obtain a product with a certain viscosity. On the one hand, the addition of edible gum will affect the taste of the pear paste, and the prepared pear paste usually does not have the properties of a thick semi-fluid. On the other hand, the pear paste prepared by the vacuum concentration method lacks the color and flavor produced by the Maillard reaction and caramelization reaction during high-temperature boiling, which reduces consumers' recognition of the product. Therefore, it is of great significance for both enterprises and consumers to prepare pear paste products with certain efficacy and traditional viscosity and sweet flavor. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a pear paste with anti-inflammatory effect and a preparation method thereof, which adopts low-temperature vacuum concentration combined with reducing sugar to accelerate the boiling process, shortens the time of pear paste under high temperature conditions, reduces the degradation of active ingredients, enhances the anti-inflammatory effect of pear paste, and makes pear paste have thick semi-fluid properties and unique color and flavor. In addition, based on the synergistic effect, pear paste is compounded with medicinal and edible substances to further enhance the anti-inflammatory effect of pear paste products.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for preparing a pear paste having anti-inflammatory effect, comprising the following steps:

[0007] (1) Pretreatment: Wash and slice fresh pears, then boil the pear slices in boiling water for 10 min, cool them in cold water, and squeeze out the juice to obtain pear pulp;

[0008] (2) enzymatic hydrolysis: enzymatically hydrolyzing the pear pulp obtained in step (1) with cellulase and pectinase, then inactivating the enzymes at high temperature, and squeezing and filtering to obtain pear juice after cooling;

[0009] (3) low-temperature vacuum concentration: preliminarily concentrating the pear juice obtained in step (2) under vacuum conditions to obtain concentrated pear juice;

[0010] (4) high temperature boiling: adding reducing sugar to the concentrated pear juice obtained in step (3), and boiling at high temperature;

[0011] (5) Canning: The pear paste obtained in step (4) is transferred to a cooling device, and then low-temperature canned to obtain a finished pear paste.

[0012] In one embodiment of the present invention, the amount of cellulase added in step (2) is 0.1-0.3% of the mass of the pear pulp; the amount of pectinase added is 0.01-0.1% of the mass of the pear pulp.

[0013] In one embodiment of the present invention, the usage ratio of cellulase to pectinase in step (2) is 3 to 10:1.

[0014] In one embodiment of the present invention, in step (2), the enzymatic hydrolysis temperature is 40-50° C., the enzymatic hydrolysis time is 30-90 min, and the enzyme inactivation conditions are 80-90° C. and 30-50 min.

[0015] In one embodiment of the present invention, in step (3), the vacuum degree during the initial concentration is 0.01-0.1 MPa, the concentration temperature is 50-70°C, and the concentration is performed until the soluble solids are 50-60° Brix.

[0016] In one embodiment of the present invention, the reducing sugar in step (4) includes one or more of xylose, glucose, fructose, lactose and maltose, wherein the amount of reducing sugar added is 0.2-2% of the mass of the concentrated pear juice.

[0017] In one embodiment of the present invention, the reducing sugar in step (4) is pentose, including one or more of xylose, arabinose, and ribose.

[0018] In one embodiment of the present invention, in step (4), the high temperature cooking temperature is 120-150°C, and the cooking is performed until the soluble solids are 75-80°Brix.

[0019] The invention also provides a pear paste with anti-inflammatory effect prepared according to the method.

[0020] The present invention also provides a pear paste compound with anti-inflammatory effect, the pear paste compound comprises the above-mentioned pear paste and a water extract of medicinal and edible properties, the water extract of medicinal and edible properties comprises at least one of honeysuckle, licorice, lily, tangerine peel, mulberry leaf, mint, gardenia, chrysanthemum, momordica grosvenori, and loquat leaf water extract.

[0021] In one embodiment of the present invention, the water extract of medicine and food is an extract obtained by filtering the above-mentioned material after being extracted with hot water at a solid-liquid ratio of 1:20-60 (w / w) for 30 minutes.

[0022] In one embodiment of the present invention, the mass ratio of the pear paste to the medicinal and edible water extract is 6:(1-6).

[0023] The invention also provides an application of the pear paste in functional food.

[0024] Beneficial effects of the present invention:

[0025] (1) The present invention uses low-temperature vacuum concentration to quickly remove water to increase the solid content, and then adds reducing sugar to induce the system to more quickly undergo Maillard reaction and caramelization reaction, thereby greatly shortening the high-temperature cooking time.

[0026] (2) For the pear juice after enzymatic hydrolysis, the present invention first uses a low-temperature vacuum concentration method for preliminary concentration, and then combines reducing sugar and high-temperature boiling methods for further concentration. Low-temperature vacuum concentration helps to increase the content of total phenols and triterpenoid compounds, and low-temperature vacuum concentration combined with reducing sugar catalysis and short-term high-temperature boiling can greatly increase the content of total flavonoids. At the same time, the prepared pear paste has the properties of a thick semi-fluid, and its viscosity can reach 70% of that of conventional high-temperature boiled pear paste. In addition, the color difference between the pear paste prepared by the method of the present invention and the conventional high-temperature boiled pear paste is not large, and it is difficult for ordinary people to observe the difference.

[0027] (3) The type of reducing sugar not only affects the content of active substances such as total phenols, flavonoids and triterpenoids in the final prepared pear paste, but also has a significant effect on the composition and content of volatile substances in the pear paste. The effect of using pentose to accelerate the Maillard reaction is better than that of hexose, which ultimately leads to the highest total amount of volatile compounds in the pear paste with pentose participating in the reaction. After adding 2% xylose, the total amount of volatile compounds in the pear paste is as high as 10709.32μg / kg, and the contents of aldehydes and furans are 6666.28μg / kg and 2516.97μg / kg, respectively.

[0028] (4) In the pear paste with the participation of reducing sugars, the Maillard reaction and caramelization reaction produce a large amount of furan and its derivatives, which are important aroma compounds in the pear paste. For example, 2-furan methanol is an important source of malt sweetness, caramel flavor and baking aroma. The furan compound content in the pear paste prepared using pentose as a reducing sugar is 2516.77 μg / kg, which is much higher than hexose (1937.14 μg / kg). The vacuum concentration combined with the reducing sugar boiling process not only does not lose the unique flavor of the pear paste, but increases the unique volatile flavor content, among which the flavor enhancement effect of pentose is more significant.

[0029] (4) Compared with the traditional process, after adding 2% xylose to the concentrated pear juice and boiling it at high temperature (120℃), the total phenol content in the pear paste reached 14.94 mg / g DW, which is 3.97 times that of the traditional high-temperature boiled pear paste. The triterpenoid content reached 2.12±0.03 mg / g DW, which is 8.48 times that of the traditional high-temperature boiled pear paste. The total flavonoid content was increased by 78.6% compared with the traditional pear paste.

[0030] (5) The pear paste prepared by the method of the present invention has a good anti-inflammatory effect. Compared with the traditional pear paste, the BSA denaturation inhibition rate of the pear paste prepared by the method of the present invention is increased by 52.4% and can reach 12.57%.

[0031] (6) The addition of edible and medicinal substances can significantly enhance the anti-inflammatory effect of pear paste. The experiment found that when pear paste was compounded with tangerine peel, chrysanthemum, honeysuckle, and lily, the anti-inflammatory effect of the prepared pear paste compound was significantly greater than the sum of the anti-inflammatory effects of single pear paste and single tangerine peel, chrysanthemum, honeysuckle, or lily, indicating that there is a synergistic effect between pear paste and edible and medicinal substances in terms of anti-inflammatory effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 To study the effects of different boiling temperatures on some active ingredients in pear paste;

[0033] Figure 2 The contents of phenolic, flavonoid and triterpenoid compounds in pear paste obtained at different boiling temperatures;

[0034] Figure 3 The antioxidant activity of pear paste obtained at different boiling temperatures;

[0035] Figure 4 To investigate the in vitro anti-inflammatory potential of different pear paste compound ingredients;

[0036] Figure 5 It is the content of inflammatory factors in mouse serum and tissues. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0038] Test method:

[0039] (1) The total phenol content was determined by the Folin-Ciocalteau method: 0.1 mL of sample was mixed with 0.5 mL of Folin-Ciocalteau reagent, 2.0 mL of 7.5% sodium carbonate solution and 7.4 mL of distilled water, and deionized water was set as a blank control. The reaction was protected from light for 30 minutes, and then the absorbance was measured at 750 nm.

[0040] (2) The total flavonoid content was determined by the NaOH-NaNO2-AlCl3 method: 1.0 mL of sample was mixed with 0.3 mL of 5% NaNO2 and reacted at room temperature for 5 min, while deionized water was set as a blank control. Then 0.3 mL of 10% AlCl3 was added and incubated for another 6 min. Subsequently, 4 mL of 1 M NaOH and 4.4 mL of water were added, and after standing for 12 min, the absorbance was measured at 510 nm.

[0041] (3) Phenolic acid content Phenolic acid in pear paste was determined by HPLC: Phenolic acid was separated using a Waters Atlantis C18 reverse phase column (length 15 cm, inner diameter 4.6 mm, particle size 3 μm). Mobile phase A was ultrapure water containing 0.1% acetic acid by volume, and mobile phase B was acetonitrile containing 0.1% acetic acid by volume. The gradient elution program was as follows: 0 min to 5 min, 30% B; 5 min to 10 min, 40% B; 10 min to 20 min, 45% B; 20 min to 22 min, 100% B; 22 min to 25 min, 7% B. The flow rate was set to 0.6 mL / mi, and the column temperature was set to 30°C. Phenolic acids in phenolic body fluids were identified and quantified by comparing the retention time and peak area of ​​the samples.

[0042] (4) Apparent viscosity: The rheological properties of pear paste were measured and characterized using a DHR3 rheometer. A 40 mm parallel plate was used and the temperature was set to 25 °C. First, the rheometer was calibrated, and then an appropriate amount of pear paste was transferred onto the parallel plate, and the excess was wiped off to start the test. The shear rate was set to 0.1 to 100 s -1 , record the viscosity changes of different pear pastes, and record the shear rate 1s -1 The apparent viscosity of the

[0043] (5) Color measurement: Color parameters were measured using a colorimeter. The pear paste was diluted tenfold, and the color parameters were expressed as L*, a*, and b*, where L* represents the brightness value, a* represents the green / red value, and b* represents the blue / yellow value. In addition, the color difference (△E) was calculated using the following formula:

[0044]

[0045] (6) Sensory evaluation standards are as follows:

[0046]

[0047]

[0048] (6) Evaluation of in vitro anti-inflammatory activity: The anti-inflammatory potential of the extract and its combination with pear paste was evaluated in vitro by testing the effect on the denaturation of bovine serum albumin (BSA). 0.1 mL of the sample was added to 0.9 mL of BSA solution (0.7%, prepared in phosphate buffer solution with a pH of 6.9), and deionized water was used as a control. The mixture was incubated at 37°C for 20 min and then heated at 70°C for 10 min. After cooling, 5 mL of deionized water was added and the absorbance at 660 nm was measured.

[0049] The BSA denaturation inhibition rate was calculated according to the following equation:

[0050]

[0051] Example 1

[0052] Wash and slice fresh Gaoping yellow pears, then boil the pear slices in boiling water for 10 minutes, then cool them in cold water and squeeze out the juice to obtain pear pulp. Then add 0.15% of cellulase and 0.03% of pectinase, enzymolyze in a reactor at 50°C for 70 minutes, inactivate the enzymes and filter to obtain enzymolyzed juice. Pour the enzymolyzed pear juice into a rotary evaporator and concentrate it under a vacuum of 0.01MPa until the soluble solids are 50°Brix. Then add 2.0% (w / v) xylose to the concentrated pear juice, then boil it at 120°C until the soluble solids are 78°Brix, and finally cool and can it to obtain pear paste.

[0053] Example 2

[0054] The difference between Example 2 and Example 1 is that the boiling temperature after adding xylose is 150°C.

[0055] Example 3

[0056] The difference between Example 3 and Example 1 is that the amount of xylose added is 0.5%.

[0057] Example 4

[0058] The difference between Example 4 and Example 1 is that the amount of xylose added is 1%.

[0059] Example 5

[0060] The difference between Example 5 and Example 1 is that xylose is replaced by glucose.

[0061] Comparative Example 1

[0062] Wash and slice fresh Gaoping yellow pears, then boil the pear slices in boiling water for 10 minutes, then cool them in cold water and squeeze out the juice to get pear pulp. Then add 0.15% cellulase and 0.03% pectinase, enzymolyze in a reactor at 50°C for 70 minutes, then heat in a 90°C water bath for 30 minutes to inactivate the enzymes, and finally filter to get enzymolyzed pear juice. Pour the enzymolyzed pear juice into a stainless steel pot, heat and boil at 120°C until the soluble solids of the pear juice are 78°Brix, stop heating, cool and can to get pear paste.

[0063] Comparative Example 2

[0064] Wash and slice fresh Gaoping yellow pears, then boil the pear slices in boiling water for 10 minutes, then cool them in cold water and squeeze out the juice to obtain pear pulp. Then add 0.15% cellulase and 0.03% pectinase, enzymolyze in a reactor at 50°C for 70 minutes, then heat in a 90°C water bath for 30 minutes to inactivate the enzymes, and finally filter to obtain enzymolyzed pear juice. Add 2.0% (w / v) xylose to the enzymolyzed pear juice, heat and boil at 120°C until the soluble solids of the pear juice are 78°Brix, stop heating, cool and can to obtain pear paste.

[0065] Comparative Example 3

[0066] The difference between Comparative Example 3 and Example 1 is that the cooking temperature after adding xylose is 180°C.

[0067] Comparative Example 4

[0068] The difference between Comparative Example 4 and Example 1 is that the amount of xylose added is 0.

[0069] Comparative Example 5

[0070] The difference between Comparative Example 5 and Example 1 is that the amount of xylose added is 4%.

[0071] Comparative Example 6

[0072] The difference between Comparative Example 6 and Example 1 is that the solid content after vacuum concentration is 30° Brix.

[0073] Comparative Example 7

[0074] The difference between Comparative Example 7 and Example 1 is that the solid content after vacuum concentration is 70° Brix.

[0075] Comparison Example

[0076] Fresh Gaoping yellow pears were washed and sliced, then the pear slices were boiled in boiling water for 10 minutes, then cooled in cold water and squeezed to obtain pear pulp. Subsequently, 0.15% cellulase and 0.03% pectinase were added, and enzymolysis was performed in a reactor at 50°C for 70 minutes, then heated in a water bath at 90°C for 30 minutes to inactivate the enzymes, and finally filtered to obtain enzymolysis pear juice.

[0077] Example 1, Comparative Examples 1 and 2 compared and demonstrated the effects of boiling and concentration processes on boiling time, active ingredient content and viscosity of pear paste, and the results are shown in Table 1.

[0078] Table 1 Preparation time, active ingredients and viscosity of pear paste samples with different processes

[0079]

[0080] Note: The time is the time consumed for 250g of pear juice.

[0081] Table 2 Color of pear paste samples with different processes

[0082]

[0083] As can be seen from Table 1, the total preparation time of the pear paste of Comparative Example 1, Comparative Example 2 and Example 1 is 145min, 120min and 88min respectively. Among them, the high temperature stage time of Example 1 is only 28min. The content of active ingredients such as polyphenols in the pear paste sample is positively correlated with the boiling time. The longer the high temperature boiling time, the lower the content of active ingredients. Taking polyphenols as an example, the total phenol content of Example 1 is 3.97 times and 3.6 times that of Comparative Examples 1 and 2, respectively. This is because polyphenols are prone to degradation, oxidation or polymerization under high temperature conditions, and long-term high temperature boiling is more likely to lead to the loss of polyphenols in the pear paste. Compared with Comparative Example 1, xylose was added to Comparative Example 2 before boiling. The addition of xylose promoted the Maillard reaction and caramelization reaction in the pear paste system, shortening the boiling time from 145min to 120min. Due to the shortening of the high temperature boiling time, the total phenol and total flavonoid content increased compared with Comparative Example 1. In addition, by analyzing the apparent viscosity of the pear paste samples, the viscosity of the pear paste prepared by the traditional process (Comparative Example 1) is the largest, followed by Comparative Example 2, and the viscosity of Example 1 is relatively low. However, compared with the change ratio of the active ingredient, the viscosity of Example 1 can reach 70% of the viscosity of Comparative Example 1.

[0084] As can be seen from Table 2, L* represents the brightness value, a* represents the green / red value, and b* represents the blue / yellow value, wherein the higher a* represents the redder, and the higher b* represents the yellower. The traditional high-temperature boiled pear paste (Comparative Example 1) is reddish brown, and a* is 19.85±1.10. The a* of Comparative Example 2 is 30.35±1.11, showing a dark red color, and the color difference is 19.16 compared to Comparative Example 1. A large number of studies have shown that when the ΔE value is between 1.6 and 3.2, the human eye basically cannot distinguish the difference in color. Between 3.2 and 6.5, professionally trained people can distinguish the difference, but ordinary people cannot observe the difference. Between 6.5 and 13, the color difference can be distinguished, and between 13 and 25, it can be determined that it is a different color tone. It can be seen that the color of Comparative Example 2 is much darker than that of Comparative Example 1, and the naked eye can easily find the difference. This is because Maillard reaction and caramelization reaction will occur during high-temperature cooking. The addition of xylose in Comparative Example 2 causes these reactions to intensify for a long time, producing too much brown matter. In comparison, the a* of Example 1 is 17.54±0.35, which is lower than that of Comparative Example 1. The color difference ΔE value between the two is 3.64, indicating that the overall color difference is not very obvious. This shows that although the high-temperature cooking stage of Example 1 is only 28 minutes, the addition of appropriate xylose to promote the Maillard reaction and caramelization reaction can achieve the color effect of long-term high-temperature cooking.

[0085] The effects of high temperature boiling temperature on boiling time, active ingredient content and viscosity of pear paste after vacuum concentration were compared in Examples 1 and 2 and Comparative Example 3. The results are shown in Tables 3 and Figure 2 shown.

[0086] Table 3 Effect of high temperature boiling on the preparation time, active ingredients and viscosity of pear paste

[0087]

[0088] Table 4 Effect of high temperature boiling temperature on the color of pear paste

[0089]

[0090] It can be seen from Table 3 that the higher the boiling temperature, the shorter the time of the high temperature stage. Unexpectedly, compared with the unboiled pear juice, the total phenol and total flavonoid contents in the pear paste after the boiling step are significantly increased. Compared with the control example, the total phenol contents of the pear pastes of Example 1 (120°C), Example 2 (150°C), and Comparative Example 3 (180°C) are increased by 7.4 times, 5.2 times, and 4.0 times, respectively. In fruits and vegetables, polyphenols and flavonoids are usually covalently bound to insoluble polymers, and the energy provided by boiling can degrade the cell wall structure and destroy the binding state, thereby promoting the release of these biologically active substances. The specific changes in active ingredients are as follows: Figure 1 Among them, coumaric acid is the substance that increases the most after boiling, and is the main phenolic acid in the pear paste. The pear paste prepared by boiling at 120°C has the highest coumaric acid content, which is 7611.66±111.44μg / g DW. Coumaric acid is a cross-linking agent for plant cell walls, and mainly exists in the form of ether bonds or ester bonds. It can combine with cellulose to form a complex, and its degree of binding with cellulose is higher than that of other phenolic acids. High-temperature boiling can affect the structure of cellulose, and thus affect the content of coumaric acid. However, compared with Example 1 (120°C), the coumaric acid content in the pear paste prepared by Example 2 (150°C) and Comparative Example 3 (180°C) is relatively lower, which may be because too high a boiling temperature will destroy its structure, thereby causing partial degradation of coumaric acid. In general, the high-temperature boiling step effectively increases the polyphenol content in the pear paste, among which the boiling temperature of 120°C has a relatively better effect.

[0091] As can be seen from Table 4, compared with the control example, after high-temperature boiling, L* significantly decreased, and a* and b* values ​​significantly increased, indicating that the pear paste showed a reddish brown color. Compared with Example 1 (120°C), Example 2 (150°C) and Comparative Example 3 (180°C), a* and boiling temperature were negatively correlated, and b* and △E were positively correlated with boiling temperature. The higher the boiling temperature, the smaller a*, b* and △E were higher, indicating that the pear paste of Example 2 (150°C) and Comparative Example 3 (180°C) was not deep red, but bright yellow, especially Comparative Example 3 (180°C). This is because the high temperature (180°C) caused the boiling time to be significantly reduced, and the Maillard reaction and caramelization reaction were insufficient.

[0092] Figure 3The effect of high temperature cooking temperature on the antioxidant activity of pear paste is also given. Figure 3 It can be seen that with the increase of temperature, the antioxidant activity of pear paste decreases, which is related to the decrease in the content of antioxidant active substances such as phenolic acids and flavonoids in pear paste.

[0093] Example 1, Examples 3-4 and Comparative Example 4 were compared to demonstrate the effect of xylose addition on the boiling time, active ingredient content and viscosity of pear paste. The results are shown in Table 3.

[0094] Table 5 Effect of xylose addition ratio on pear paste preparation time, active ingredients and viscosity

[0095]

[0096] Table 6 Effect of xylose addition ratio on pear paste color

[0097]

[0098] As can be seen from Table 5, with the increase of the proportion of xylose added, the time required for high-temperature boiling of the system gradually decreases, but when the amount of xylose added exceeds 2%, there is no significant difference in the content of active substances. Through sensory analysis, as the amount of xylose added increases from 0.5% to 2%, the sensory score of pear paste increases, which may be because the addition of xylose promotes the Maillard reaction and is conducive to the production of sweet potato-like sweet smell in pear paste. However, when the amount of xylose added increases to 4%, the sensory evaluation clearly feels that there is a significant bitter taste in the pear paste, which may be because excessive xylose causes improper caramelization reaction of sugar during boiling. Therefore, xylose should not be added excessively. In addition, as can be seen from Table 6, with the increase of the proportion of xylose added, the △E of pear paste first decreases, and the color gradually approaches that of traditional process products. When the proportion of xylose added exceeds 2%, the △E of pear paste rises again, indicating that too much xylose makes the color of pear paste darker, which may be due to the production of too much brown matter.

[0099] Comparative Example 1, Example 1 and Example 5 compared and demonstrated the effect of the type of reducing sugar on the boiling time, active ingredient content and viscosity of the pear paste, and the results are shown in Table 7. Table 9 also gives the data on the content of volatile substances in the pear paste of Comparative Example 1, Example 1 and Example 5.

[0100] Table 7 Preparation time, active ingredients and viscosity of pear paste samples with different reducing sugar additions

[0101]

[0102] Table 8 Color difference of pear paste samples when different reducing sugars were added

[0103]

[0104] As can be seen from Table 7, due to the short time in the high-temperature boiling stage, the content of active substances such as polyphenols in the products of Example 1 (xylose) and Example 5 (glucose) is higher than that in Comparative Example 1. However, compared with Example 1 (xylose), Example 5 (glucose) requires a longer high-temperature time to prepare the pear paste product, which results in lower active substances such as polyphenols than Example 1 (xylose). On the other hand, as can be seen from Table 8, the ΔE of Example 5 reaches 7.93, and the color difference is visible to the naked eye.

[0105] Table 9 Volatile substance content in pear paste (μg / kg)

[0106]

[0107]

[0108] Pears are rich in carbohydrates, dietary fiber, protein, minerals, vitamins and other nutrients. Studies have shown that during high-temperature cooking, Maillard reaction and caramelization reaction will occur in the pear paste system, which give the pear paste a pleasant aroma. The Maillard reaction is a reaction between carbonyl compounds (reducing sugars) and amino compounds (amino acids and proteins). The addition of reducing sugars such as xylose (pentose) and glucose (hexose) can promote the Maillard reaction of the system. In order to explore the effect of reducing sugar types on the flavor of pear paste, the types and contents of volatile components in pear paste were determined by SPME-GC-MS.

[0109] The volatile flavor substances in pear paste mainly include 11 alcohols, 10 furans, 7 ketones, 5 acids, 4 aldehydes, 6 esters, etc. Among them, furans and aldehydes are the main components of volatile components in pear paste, accounting for more than 85% in total, among which aldehydes account for the highest proportion, about more than 60%, followed by furans, about 20% to 25%. As can be seen from Table 5, Example 1 has the highest total amount of volatile compounds, which is 10709.32μg / kg, and the contents of aldehydes and furans are 6666.28μg / kg and 2516.97μg / kg respectively. Example 5 (glucose) is second, and the content of comparative example 1 is the lowest.

[0110] The Maillard reaction and caramelization reaction in pear paste produce a large amount of furan and its derivatives, which are important aroma compounds in pear paste. For example, 2-furan methanol is an important source of malt sweetness, caramel flavor and baking aroma. The furan compound contents of Comparative Example 1, Example 1 (xylose) and Example 5 (glucose) are 1232.72 μg / kg, 2516.77 μg / kg and 1937.14 μg / kg, respectively, accounting for 12.5%, 20.5% and 16.8%, respectively. The results show that vacuum concentration combined with reducing sugar boiling process will not only not lose the unique flavor of pear paste, but increase the unique volatile flavor content, among which the flavoring effect of xylose is more significant than that of glucose. In short, from the perspective of active ingredient content, color difference and flavor, xylose is better than glucose.

[0111] Example 1, Comparative Examples 6 and 7 compared and demonstrated the effect of solid content after vacuum concentration on the boiling time, active ingredient content and viscosity of pear paste. The results are shown in Table 10.

[0112] Table 10 Effect of vacuum concentration degree on pear paste time, active ingredients and viscosity

[0113]

[0114] Table 11 Effect of vacuum concentration degree on pear paste color

[0115]

[0116] As can be seen from Tables 10 and 11, when the vacuum concentration degree is low (Comparative Example 6, 30°Brix), the high-temperature boiling time is still long, resulting in a decrease in the active ingredients in the pear paste and an overly dark color. When the vacuum concentration degree is too high (Comparative Example 7, 70°Brix), the high-temperature boiling is not sufficient, the system viscosity is only 46% of the viscosity of the traditional pear paste, the color is too light, and its sensory quality is affected.

[0117] Example 6 Preparation of pear paste compound

[0118] The BSA denaturation inhibition rate was used to evaluate the anti-inflammatory potential of pear paste compound in vitro. Honeysuckle, licorice, lily, tangerine peel, mulberry leaf, mint, gardenia, chrysanthemum, monk fruit, and loquat leaf were added to boiling water at a mass ratio of 1:20 for liquid to solid ratio, and hot extraction was performed for 15 minutes. After natural cooling, the extract was filtered to obtain the extract. This process was repeated 3 times, and the extracts were combined and then vacuum concentrated at 40°C to make the volume of the liquid before concentration 5 times that after concentration, and reserved as the raw material mother liquor for standby. Pear paste was mixed with each concentrated mother liquor at a mass ratio of 6:1 to prepare a pear paste compound.

[0119] Figure 4 The anti-inflammatory potential of each medicinal and edible water extract was shown. Figure 4It can be seen that honeysuckle, licorice, lily, tangerine peel, mulberry leaf, mint, gardenia, chrysanthemum, monk fruit and loquat leaf have a certain inhibitory ability against BSA at a thermal denaturation temperature of 70°C. At the same concentration, all raw materials showed different degrees of anti-inflammatory potential. Tangerine peel showed the highest anti-inflammatory potential, with a BSA denaturation inhibition rate of 29.25±0.17%. The BSA denaturation inhibition rates of gardenia, chrysanthemum, monk fruit and loquat leaf were in the range of 20-25%, while the inhibition rates of honeysuckle, licorice, lily and mint were about 10%. However, the anti-inflammatory potential of mulberry leaf was significantly lower than that of other raw materials, providing only 2.04±0.09% of BSA thermal denaturation protection.

[0120] Example 7 Evaluation of the in vitro anti-inflammatory effect of pear paste and its pear paste-compound

[0121] On the basis of Example 6, the mulberry leaves with the lowest BSA denaturation inhibition rate were removed, and the BSA denaturation inhibition rate after the remaining raw materials and pear paste were compounded was investigated. The theoretical denaturation inhibition rate is the "additive" value of pear paste and any raw material.

[0122] As can be seen from Table 12, for a single pear paste, the BSA inhibition rate of the pear paste of Example 1 is significantly higher than that of Comparative Example 1 and Comparative Example 3, which is attributed to the higher total phenols, total flavonoids and triterpenoids contained in 2% xylose-pear paste. It shows that the process of vacuum concentration combined with the addition of xylose helps to improve the anti-inflammatory ability of the pear paste. When the pear paste is compounded, the BSA inhibition rate of the compound is significantly higher than that of a single pear paste and a single medicinal and edible water extract. For compounded pear paste, the BSA denaturation inhibition rate of the pear paste-tangerine peel compound is the highest, followed by the pear paste-chrysanthemum compound. By comparing with the theoretical denaturation inhibition rate, the pear paste-tangerine peel compound, the pear paste-chrysanthemum compound, the pear paste-honeysuckle compound, and the pear paste-lily compound all have a synergistic effect.

[0123] Table 12 In vitro anti-inflammatory effects of pear paste and pear paste-compounds

[0124]

[0125]

[0126] Example 8 Selection of pear paste-compound ratio

[0127] On the basis of Example 7, the in vitro anti-inflammatory effects of the pear paste-tangerine peel compound, pear paste-chrysanthemum compound, pear paste-honeysuckle compound, and pear paste-lily compound ratio were studied. As can be seen from Table 13, by comparing the BSA denaturation inhibition rate and the theoretical denaturation inhibition rate, the four compound combinations with a ratio of 6:1 all have a synergistic effect, among which the pear paste-tangerine peel compound has the highest inhibition rate. For the pear paste-tangerine peel compound, as the compound ratio increases, the denaturation inhibition rate of BSA gradually decreases, while for the pear paste-chrysanthemum compound, when the compound ratio is 6:3, the denaturation inhibition rate of BSA is the highest. Therefore, the pear paste-tangerine peel compound (6:1) and the pear paste-chrysanthemum compound (6:3) were selected for subsequent research.

[0128] Table 13 Effect of pear paste compound ratio on BSA denaturation inhibition rate

[0129]

[0130]

[0131] Example 9 Evaluation of the in vivo anti-inflammatory effect of pear paste and its compound

[0132] Mouse ear swelling experiment: After one week of adaptive feeding, all mice were randomly divided into 7 groups according to body weight. The specific experimental groups and dosing regimens are shown in Table 4, and the mice were kept for another 30 days. After the last administration, 20 μL of xylene was evenly applied to the left auricle of each mouse. After 30 minutes, the mice were anesthetized, and blood samples were collected from the eyeballs before the mice were killed by dislocating the cervical vertebra. Subsequently, both ears were cut off along the auricle baseline, and a 9 mm diameter puncher was used to punch the same size ear pieces at the same position of both ears and weighed immediately. The auricle swelling value was calculated by the difference in the weight of the two ears, and the auricle swelling inhibition rate was calculated accordingly. The formula is as follows:

[0133]

[0134] Determination of inflammatory factors in vivo: For the level of inflammatory cytokines in serum, the blood samples were allowed to stand for 20 min and centrifuged (3500 r / min, 20 min) to obtain the supernatant. Subsequently, the levels of IL-6, IL-1β, and TNF-α in serum were evaluated using ELISA kits.

[0135] For the level of inflammatory cytokines in tissues, the chopped ear tissue samples were homogenized in cold PBS (pH = 7.4) using a homogenizer. After centrifugation at 5000r / min for 20min, the protein content in the supernatant was detected using an enhanced BCA protein detection kit. At the same time, the cytokine concentration (IL-6, IL-1β, TNF-α) in the supernatant was evaluated using an ELISA kit, and the cytokine level in the tissue was calculated using the following formula:

[0136]

[0137] Based on the in vitro antioxidant effect of Example 8, the 2% xylose-pear paste in Example 1 was used as the pear paste group, and based on Example 8, pear paste-tangerine peel (6:1) and pear paste-chrysanthemum (6:3) were selected as compound groups for animal experiments.

[0138] Table 14 Drug administration in different groups

[0139]

[0140] As can be seen from Table 8, after continuous feeding of mice for 30 days, it was observed that the mice in the control group and each dose group showed normal diet and excretion of urine and feces, and no other adverse reactions occurred in behavior and growth and development. According to the changes in the weight of mice in Table 14, it can be found that during the one-week adaptation period before feeding, the weight of all mice increased to varying degrees, indicating that the mice adapted well to the environment and the current environment was suitable for their growth and development. 4 days before gavage, the blank group and the model group showed a trend of weight gain, but the weight of mice in the other groups decreased, indicating that the gavage of other substances had a slight negative impact on the weight of mice. During the period from 4 days to the end of gavage, the weight of mice in the pear paste group and the compound group gradually recovered over time, while the weight recovery rate of mice in the drug administration group was slower. At the end of gavage, the weight of mice in the pear paste group and the compound group was almost the same as that of the blank group and the model group, but the weight of the positive control group was significantly lower than that of other groups. Based on the observation of the physiological state of mice during feeding, it is analyzed that although dexamethasone anti-inflammatory immune drugs can play a good anti-inflammatory effect, long-term use may cause damage to the body.

[0141] Table 14 Body weight changes of mice in ear swelling experiment

[0142]

[0143] According to the experimental results in Table 14, the left ear of the model group mice showed obvious swelling after being treated with xylene, and the swelling rate was 6.23±0.55%. Compared with the model group, the auricle swelling of the mice in the treatment groups of 5g / kg body weight, 7.5g / kg body weight and two pear paste combinations was significantly reduced, which was 2.82±0.54%, 2.46±0.27%, 1.59±0.24% and 1.75±0.75% respectively. There was a statistically significant difference in the auricle swelling rate of mice in different treatment groups (F=82.495, P=0.000), indicating that the pear paste and its compound showed a positive effect in the mouse ear swelling experimental results, and all therapeutic drugs had the effect of intervening acute inflammation. The auricle swelling inhibition rate of the high-dose pear paste treatment group was 60.53%, which was higher than 54.66% of the low-dose pear paste treatment group, indicating that the inhibitory effect of pear paste was concentration-dependent. The auricle swelling inhibition rates of pear paste compound group 1 and pear paste compound group 2 were 74.49% and 71.80%, respectively, both higher than that of the pear paste treatment group. This indicates that pear paste can enhance its anti-inflammatory activity after being combined with other medicinal and edible ingredients. Among them, the auricle swelling inhibition rate of pear paste compound group 1 was the highest, higher than that of the positive control group (dexamethasone 10 mg / kg body weight) of 73.21%.

[0144] Table 15 Effects of pear paste and compound on ear swelling in mice

[0145]

[0146] Note: Different lowercase letters indicate significant differences among the groups (p<0.05).

[0147] Compared with the blank group, the IL-6 concentrations in the serum and ear tissues of the mice in the model group were significantly increased. Figure 5 As shown, the IL-6 concentration in the pear paste and compound groups was significantly lower than that in the model group (p<0.05). The inhibitory effect of pear paste and the two compound groups on IL-6 in mouse serum was almost equivalent to that of the positive group, and there was no significant difference between the groups (p>0.05). Among them, the high-dose group of pear paste with a body weight of 7.5g / kg had the strongest inhibitory effect on IL-6 in mouse serum, with a content of 103.17±8.24ng / L. The pear paste group showed a significant dose-dependent inhibitory effect on the expression of IL-6 in mouse ear tissue. The IL-6 content in the high-dose group of pear paste with a body weight of 7.5g / kg was 82.53±11.83ρg / mg protein, which was significantly lower than that in the low-dose group of pear paste with a body weight of 5g / kg (p<0.05). The IL-6 content in the mouse ear tissue of the two pear paste compound groups was lower than that in the low-dose group of pear paste.

[0148] Compared with the blank group, the IL-1β concentrations in the serum and ear tissues of the mice in the model group were significantly increased. Figure 5As shown, the IL-1β concentration in the pear paste and compound groups was significantly lower than that in the model group (p<0.05). The positive control group, different concentrations of pear paste groups and two pear paste compound groups had comparable inhibitory effects on IL-1β in mouse serum, with no significant difference (p>0.05). The pear paste group had a dose-dependent effect on the level of IL-1β, among which the level of IL-1β in the 7.5g / kg body weight pear paste group was 17.81±3.62ρg / mg protein, which was significantly lower than that in the low-dose pear paste group (p<0.05). The inhibitory effects of the two pear paste compounds on the level of IL-1β were very small, both significantly lower than the low-dose pear paste group, and comparable to the high-dose pear paste group and the positive group. Among them, the pear paste compound mixed with chrysanthemum had the lowest IL-1β content, which was 12.79±2.00ρg / mg protein.

[0149] Compared with the blank group, the TNF-α concentrations in the serum and ear tissues of the mice in the model group were significantly increased. Figure 5 As shown in the figure, except for the low-dose pear paste group and compound group 2, the other groups significantly reduced the TNF-α concentration in the mouse serum compared with the model group (p<0.05). The TNF-α concentration in the mouse serum of the low-dose pear paste group (5g / kg body weight) was equivalent to that of the model group, but the TNF-α concentration in the high-dose pear paste group (7.5g / kg body weight) and compound group 1 (a compound of pear paste, tangerine peel and loquat leaves) was significantly reduced. All groups had a significant effect on reducing the TNF-α concentration in the mouse ear tissue (p<0.05). Compared with the low-dose pear paste group (1758.13±40.05ρg / mg protein), the high-dose pear paste group and compound group 1 had a more significant effect on reducing the TNF-α concentration in the mouse tissue, which was 847.80±63.16 and 1092.23±125.61ρg / mg protein, respectively. However, there was no significant difference between the pear paste compound group 2 and the low-dose pear paste group (p>0.05). The results showed that 5g / kg body weight and 7.5g / kg body weight pear paste had a significant dose-dependent inhibitory effect on the expression of TNF-α in mouse serum and ear tissue, and the combination of tangerine peel and pear paste enhanced the inhibitory effect of pear paste on TNF-α levels, but the chrysanthemum compound group did not have this enhancement effect.

[0150] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing pear paste with anti-inflammatory effect, characterized in that: The following steps are involved: (1) Pretreatment: Wash and slice fresh pears, then boil the pear slices in boiling water for 10 min, cool them in cold water, and squeeze out the juice to obtain pear pulp; (2) enzymatic hydrolysis: enzymatically hydrolyzing the pear pulp obtained in step (1) with cellulase and pectinase, then inactivating the enzymes at high temperature, and squeezing and filtering to obtain pear juice after cooling; (3) low-temperature vacuum concentration: preliminarily concentrating the pear juice obtained in step (2) under vacuum conditions to obtain concentrated pear juice; (4) high temperature boiling: adding reducing sugar to the concentrated pear juice obtained in step (3), and boiling at high temperature; (5) Canning: The pear paste obtained in step (4) is transferred to a cooling device, and then low-temperature canned to obtain a finished pear paste.

2. The preparation method according to claim 1, characterized in that: The amount of cellulase added in step (2) is 0.1-0.3% of the mass of the pear pulp; the amount of pectinase added is 0.01-0.1% of the mass of the pear pulp.

3. The preparation method according to claim 1, characterized in that: The dosage ratio of cellulase to pectinase in step (2) is 3 to 10:

1.

4. The preparation method according to claim 1, characterized in that: In step (2), the enzymolysis temperature is 40-50° C., the enzymolysis time is 30-90 min, and the enzyme inactivation conditions are 80-90° C. and 30-50 min.

5. The preparation method according to claim 1, characterized in that: In step (3), the vacuum degree during the initial concentration is 0.01-0.1 MPa, the concentration temperature is 50-70°C, and the concentration is performed until the soluble solids are 50-60° Brix.

6. The preparation method according to claim 1, characterized in that: The reducing sugar in step (4) is pentose, including one or more of xylose, arabinose, and ribose, wherein the amount of reducing sugar added is 0.2-2% of the mass of the concentrated pear juice, and the temperature during high-temperature boiling is 120-150°C, and the boiling is performed until the soluble solids are 75-80°Brix.

7. Pear paste with anti-inflammatory effect prepared according to the preparation method according to any one of claims 1 to 6.

8. A pear paste compound with anti-inflammatory effect, characterized in that: The pear paste compound comprises the pear paste and the medicinal and edible water extract according to claim 7, wherein the medicinal and edible water extract comprises at least one of honeysuckle, licorice, lily, tangerine peel, mulberry leaf, mint, gardenia, chrysanthemum, momordica grosvenori, and loquat leaf water extracts, and the mass ratio of the pear paste to the medicinal and edible water extract is 6:(1-6).

9. The pear paste compound according to claim 8, characterized in that The food-medicine aqueous extract is an extract obtained by filtering the food-medicine substance after being extracted with hot water for 30 minutes at a material-liquid mass ratio of 1:20-60. The food-medicine substance includes at least one of honeysuckle, licorice, lily, tangerine peel, mulberry leaf, mint, gardenia, chrysanthemum, momordica grosvenori, and loquat leaf.

10. Use of the pear paste according to claim 8 or 9 in functional food.

Images