CN111528423A

CN111528423A - Original-taste olive fruit powder and preparation method thereof

Info

Publication number: CN111528423A
Application number: CN202010392940.5A
Authority: CN
Inventors: 郝小玲; 冯春梅; 黎新荣; 宾振钧; 荣涛; 檀业维; 王淋靓; 牛德宝; 任二芳; 艾静汶; 罗朝丹; 张芬; 於艳萍; 欧克纬; 罗清; 毛立彦; 赵媛; 危丹妮
Original assignee: Guangxi Subtropical Crops Research Institute
Current assignee: Guangxi Subtropical Crops Research Institute
Priority date: 2020-05-11
Filing date: 2020-05-11
Publication date: 2020-08-14
Also published as: AU2020101784A4

Abstract

The invention belongs to the technical field of food processing, and particularly relates to original-taste olive fruit powder and a preparation method thereof, wherein the method comprises the following steps: sequentially carrying out blanching enzyme deactivation, vacuum freeze drying, kernel removal and crushing on olive fruits to obtain original olive fruit powder. The fruit powder prepared by the method provided by the invention retains the original color and taste, and reduces the loss of nutritional ingredients; the results of the examples show that the fruit powder product prepared by the invention still has olive green color, while the color of the olive fruit powder obtained by the traditional preparation method of olive fruit powder is changed.

Description

Original-taste olive fruit powder and preparation method thereof

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to original-taste olive fruit powder and a preparation method thereof.

Background

Olive fruit (olive fruit) is the fruit of plant of olive genus of family oleaceae, belonging to medicine and food dual-purpose fruit, and is hard pulp, unique in flavor, slightly sour and astringent in taste, fragrant and sweet in taste after long-time chewing, capable of promoting the production of body fluid to quench thirst, suitable for fruit processing, possessing immeasurable medicinal value, and fragrant in olive smell, capable of promoting appetite, and refreshing mind. The compendium of materia medica, fruit three and olive have relevant records for this: olive produces body fluid, stops polydipsia and treats sore throat, when throat juice is chewed, all crab poison can be removed, and when the juice is in a lignan shape like black gum, native people adopt , so the juice is called elemi. At present, researches show that the olive fruit is a king of fruits containing calcium and flavone, each 100g of fresh fruits contain 200-700 mg of biological organic calcium and 2-4% of olive flavone, and the olive fruit also contains various nutrients such as vitamin c, protein, fat, saccharides, dietary fibers, phosphorus, iron and the like, and has the effects of cooling, detoxifying, resisting bacteria, diminishing inflammation, clearing throat, protecting intestinal mucosa, dispelling alcohol, protecting liver, supplementing calcium for the middle-aged and the elderly, resisting hepatitis B virus and diabetes, removing free radicals, reducing blood pressure, decomposing fat, resisting oxidation, protecting the color of meat food and the like.

At present, the olive fruit powder is applied to olive high-fiber biscuits, olive salt, mixed fruit powder and the like, but the drying technology is the traditional hot air drying, the materials are olive peel and residual pulp or olive slag, and the retention of the color, aroma and nutrient components of the olive pulp is ignored, so that the product quality is greatly changed, the loss of effective components is serious, the epidermal tissue structure is hard, and the taste is uncomfortable.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for preparing original olive fruit powder, which not only retains original color and original taste, reduces loss of nutritional ingredients, and improves palatability of olive fruit powder.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention provides a preparation method of original olive fruit powder, which comprises the following steps:

sequentially carrying out blanching, enzyme deactivation, vacuum freeze drying, kernel removal and crushing on olive fruits to obtain original olive fruit powder.

Preferably, the vacuum freeze-drying also comprises a pre-cooling treatment before the vacuum freeze-drying; the temperature of the pre-cooling treatment is 5-8 ℃, and the time is 4-6 h.

Preferably, the blanching enzyme deactivation comprises blanching with boiling water and cooling with warm water which are sequentially carried out; the temperature of the boiling water blanching is 90-95 ℃, and the time is 8-13 s; the temperature of the warm water cooling is 20-25 ℃, and the time is 25-30 s.

Preferably, the vacuum freeze-drying comprises prefreezing, sublimation drying and resolution drying which are sequentially carried out.

Preferably, the pre-freezing starting temperature is-30 ℃ to-35 ℃; the pre-freezing termination temperature is-45 ℃ to-50 ℃.

Preferably, the sublimation drying includes a first sublimation drying and a second sublimation drying which are sequentially performed; the temperature of the first sublimation drying is-25 ℃ to-30 ℃, and the time is 10h to 15 h; the temperature of the second sublimation drying is-10 ℃ to-15 ℃, and the time is 7h to 8 h; the absolute pressure of the vacuum system for sublimation drying is 80 Pa-100 Pa.

Preferably, the analysis drying includes a first analysis drying, a second analysis drying and a third analysis drying which are sequentially performed; the temperature of the first analysis drying is 5-10 ℃, and the time is 5-6 h; the temperature of the second analysis drying is 16-20 ℃, and the time is 5-6 h; and the temperature of the third analysis drying is 30-35 ℃, the time is 2-3 h, and the absolute pressure of a vacuum system of the analysis drying is 130-150 Pa, so that the dried olive fruits are obtained.

Preferably, the denucleation and crushing mode comprises the following steps: separating pulp and kernel of dried olive fruit in a constant temperature dehumidification environment to obtain olive fruit pulp; crushing the olive fruit pulp to obtain original olive fruit powder; the particle size of the original olive fruit powder is 80-300 meshes.

Preferably, the blanching enzyme deactivation comprises the steps of selection and cleaning which are carried out in sequence;

the selection mode is as follows: selecting mature olives with large and full grains, smooth surfaces and yellow-green colors, and removing diseased fruit insects; the cleaning mode is as follows: and (4) finely washing the surfaces of the obtained olive fruits by adopting clear water.

The invention also provides the original olive fruit powder obtained by the preparation method of the technical scheme, wherein the total flavone content of the original olive fruit powder is 60-66 mg/g.

The invention provides a preparation method of original olive fruit powder, which is prepared by blanching, enzyme deactivation, vacuum freeze drying, kernel removal and crushing of olive fruits. In the invention, the olive fruits are firstly blanched and enzyme-killed, so that partial polyphenol oxidase can be inactivated, enzymatic browning can be effectively prevented, meanwhile, blanching is carried out, the content of reducing sugar is reduced, non-enzymatic browning is also inhibited, and the original color of the olive fruits is kept to the maximum extent; the method is characterized in that vacuum freeze drying is carried out on the basis of blanching enzyme deactivation, pulp tissues are kept complete in the drying process, the problem that cell tissues of pulp are easily damaged in the traditional wind-heat drying process, especially oxygen enters after the pulp tissues are damaged, and the color of olive fruits is changed due to enzymatic browning reaction of the pulp is solved, meanwhile, the pulp tissues are uniform after vacuum freeze drying, so that the texture of fruit powder is fine, the problems that the naked part and the inside of the pulp are not uniform, the pulp is not easy to crush and the texture is poor when fresh fruit pulp is crushed and dried are avoided, the kernel removal and crushing after vacuum freeze drying are easier than the direct crushing of the fresh fruits, the contact time of the crushed pulp tissues and the oxygen is greatly reduced, the original state of the fresh olive fruits is kept to the maximum, and the original taste of the olive fruits is kept as far as possible. The results of the examples show that the original olive fruit powder prepared by the method has high content of flavonoid compounds, calcium and other components, the content of total flavonoids is 4 times of the content of total flavonoids in fresh fruits, the original color and the original taste of the olive fruits are reserved, the loss of nutritional components is reduced, and the palatability of the olive fruit powder is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a comparison of the color of blanched and enzyme-deactivated olive fruits at different durations, wherein a is the color of the olive fruits after the blanching and enzyme-deactivation treatment in example 1; b is the color of olive fruit after blanching and enzyme deactivation treatment of comparative example 1.

Detailed Description

The invention carries out blanching enzyme deactivation on olive fruits to obtain enzyme deactivated olive fruits. In the invention, the blanching enzyme deactivation preferably comprises blanching with boiling water and cooling with warm water which are sequentially carried out; the temperature for blanching in boiling water is preferably 90-95 ℃, and is further preferably 92-95 ℃; the time for blanching in boiling water is preferably 8 s-13 s, and more preferably 8 s-11 s; the temperature for cooling the warm water is preferably 20-25 ℃, and more preferably 23-25 ℃; the time for cooling the hot water is preferably 25 to 30 seconds, and more preferably 25 to 27 seconds. After the warm water is cooled, the olive fruits are preferably naturally drained for 30-40 min. According to the method, blanching and enzyme deactivation are adopted, so that part of polyphenol oxidase can be deactivated, enzymatic browning and non-enzymatic browning can be effectively prevented, meanwhile, the non-enzymatic browning can be also inhibited due to the reduction of the content of reducing sugar, and the original color of olive fruits can be kept to the maximum extent.

Before blanching and enzyme killing, the olive fruit pre-treatment method preferably performs material pre-treatment on the olive fruit, and comprises the steps of selection and cleaning in sequence. In the present invention, the selection is preferably performed by: selecting mature olives with large and full grains, smooth surface and yellow-green color; the variety of the olive fruit is preferably Canarium album; the picking time of the olive fruits is preferably 10-12 months; removing the diseased fruit and insect fruits; the cleaning mode is preferably as follows: the surface of the olive fruit is selected by using clear water. In the invention, the olive fruits picked in specific varieties and specific time are adopted, so that the growth components and the taste of the olive fruits are in the best state, and the nutritional components and the palatability of the original olive fruit powder are further improved.

After the enzyme-killed olive fruits are obtained, the enzyme-killed olive fruits are subjected to vacuum freeze drying to obtain the dried olive fruits. In the present invention, the vacuum freeze-drying preferably includes prefreezing, sublimation drying and resolution drying which are sequentially performed; the prefreezing, sublimation drying and resolution drying are preferably performed in a vacuum environment.

In the invention, the pre-freezing starting temperature is preferably-30 ℃ to-35 ℃, and is further preferably-33 ℃ to-35 ℃; the pre-freezing termination temperature is preferably-45 ℃ to-50 ℃, and is further preferably-48 ℃ to-50 ℃; the pre-freezing is implemented by placing a freeze-drying tray in which enzyme-killed olives are placed in a single layer in a drying bin, and keeping the freeze-drying tray at the pre-freezing temperature for a certain time; the method specifically comprises the following steps: and (3) starting the vacuum freeze dryer in advance, and when the temperature of the plate layer reaches the initial temperature of pre-freeze drying (-30 ℃ to-35 ℃), filling the olive to be pre-frozen into a freeze-drying plate in a single layer, and placing the freeze-drying plate on the plate layer of the drying bin to start pre-freezing. The temperature of the plate layer continuously decreases, the temperature of the olive also rapidly decreases, the temperature difference between the olive and the plate layer is smaller and smaller, the temperature of the olive and the plate layer basically tends to be balanced finally, and the pre-freezing is finished when the temperature of the olive and the plate layer reaches the pre-freezing termination temperature (-45 ℃ to-50 ℃).

In the invention, the material can be rapidly frozen by adopting pre-freezing, so that water in the material forms extremely small ice crystals, cell tissues are not seriously damaged, and the original taste and flavor are maintained to the maximum extent; at the same time, the method helps to maintain the cell tissue and ensures that the structural shape of the olive fruit is unchanged.

In the present invention, the sublimation drying preferably includes a first sublimation drying and a second sublimation drying which are performed in this order; the temperature of the first sublimation drying is preferably-25 ℃ to-30 ℃, and is further preferably-27 ℃ to-30 ℃; the first sublimation drying time is preferably 10 to 15 hours, and more preferably 12 to 14 hours; the temperature of the second sublimation drying is preferably-10 ℃ to-15 ℃, and is further preferably-13 ℃ to-15 ℃; the time for the second sublimation drying is preferably 7 to 8 hours, and more preferably 7.5 to 8 hours. In the present invention, the temperature of sublimation drying is measured by a thermometer of a cold trap in a vacuum freeze dryer. In the present invention, the absolute pressure of the vacuum system for sublimation drying is preferably 80 to 100Pa, and more preferably 80 to 90 Pa. In the present invention, the sublimation drying is to keep the olive fruits for a certain time under the corresponding temperature condition. According to the invention, the sublimation drying is carried out by stages, so that the material quality can be effectively ensured, the loss of the nutritional ingredients of the product is prevented, the palatability of the product is improved, the sublimation drying efficiency is improved, and the problems of poor quality, nutritional loss, damaged volume and shape and increased cost of the olive fruits caused by the long-time low-temperature or high-temperature state of the olive fruits are solved. The invention adopts precooling to quickly solidify the cell frame structure of the olive fruit pulp, provides a smooth passage for gaseous escape in the sublimation stage and improves the sublimation efficiency.

In the present invention, the analysis drying preferably includes a first analysis drying, a second analysis drying, and a third analysis drying performed in this order; the temperature of the first analysis drying is preferably 5 to 10 ℃, and more preferably 5 to 8 ℃; the time for the first analysis and drying is preferably 5 to 6 hours, and more preferably 5.5 to 6 hours; the temperature of the second analysis drying is preferably 16 to 20 ℃, and more preferably 16 to 18 ℃; the second analysis drying time is preferably 5 to 6 hours, and more preferably 5.5 to 6 hours; the temperature of the third analysis drying is preferably 30 to 35 ℃, and more preferably 30 to 33 ℃; the time for the third analysis and drying is preferably 2 to 3 hours, and more preferably 2.5 to 3 hours. In the present invention, the desorption drying temperature is set to a lamellar thermometer of a vacuum freeze dryer during drying. In the present invention, the absolute pressure of the vacuum system for the analysis and drying is 130 to 150Pa, and more preferably 130 to 140 Pa. In the present invention, the desorption drying means that the drying is maintained for a certain time under the corresponding temperature condition to realize rapid reduction of moisture. The method is used for analyzing and drying the olive fruits in sections, so that the water content of the olive fruits is quickly reduced, the influence on the nutritional ingredients of the olive fruits is reduced to the maximum extent, and meanwhile, the production cost of the original-taste olive fruit powder is reduced by adopting the sectional type analyzing and drying method provided by the invention.

The invention keeps pulp tissues in the vacuum freeze drying process, solves the problem that the color of olive fruits is changed due to enzymatic browning reaction of pulp caused by oxygen entering after the pulp cell tissues are damaged in the drying process, and simultaneously, the pulp tissues have uniform frames after the vacuum freeze drying process, so that the texture of fruit powder is fine and smooth, and the problems that the exposed part of the pulp is not uniform with the inside, the pulp is not easy to crush and the texture is poor when fresh fruits are crushed and dried into pulp are solved. In the present invention, the vacuum freeze-drying is performed in a vacuum freeze-dryer; the vacuum freeze dryer can be selected from Yuming LGJ-18S.

After blanching and enzyme deactivation, before vacuum freeze drying, the invention preferably carries out pre-cooling treatment on olive fruits, wherein the temperature of the pre-cooling treatment is preferably 5-8 ℃, and further preferably 6-7 ℃; the pre-cooling time is preferably 4 to 6 hours, and more preferably 4.5 to 5.5 hours. The method for pre-freezing the olive fruits can shorten the freeze-drying time of the olive fruits and reduce the production cost by pre-freezing, and meanwhile, the pre-freezing is equivalent to buffering, so that the phenomenon that the temperature difference generated by direct pre-freezing causes bubbles to be generated on the surfaces of the olive fruits to cause the change of the pulp tissue structure, and further the palatability of the over-original-taste olive fruit powder is influenced is avoided.

After the dried olive fruit is obtained, the invention carries out kernel removal and crushing on the dried olive fruit to obtain kernel-removed olive fruit powder. In the invention, the kernel removing and crushing is preferably carried out in a constant temperature dehumidification environment, and the dried olive fruit is subjected to pulp and kernel separation to obtain olive fruit pulp; and crushing the olive fruit pulp to obtain the original olive fruit powder. In the invention, the environment of constant temperature dehumidification has no special requirement, and the method which is well known by the technical personnel in the field can be adopted; the invention has no special requirements on the separation mode of the pulp and the kernel, and adopts the mode which is well known by the technical personnel in the field; in the embodiment of the invention, the rolling is specifically carried out by a rolling machine. In the present invention, the particle size of the primary olive fruit powder is preferably 80 to 300 mesh, and more preferably 150 to 250 mesh. This application is denucleated the dry olive fruit and is smashed, compares in the direct operation of pounding to pieces of fresh fruit easier, and the very big degree has reduced the contact time of broken pulp tissue with oxygen, and furthest's the fresh fruit original state of olive keeps the primary color original flavor of olive fruit as far as possible.

After the kernel-removed olive fruit powder is obtained, the kernel-removed olive fruit powder is subjected to fruit powder vacuum packaging treatment to obtain the original-taste olive fruit powder. The invention adopts vacuum packaging, reduces the contact between the storage period of the olive fruit powder and oxygen, finally ensures that the color of the storage period of the olive fruit powder still presents olive green, and prolongs the shelf life.

The invention also provides the original-taste olive fruit powder prepared by the preparation method in the technical scheme. In the invention, the total flavone content of the original olive fruit powder is 60 mg/g-66 mg/g, and more preferably 60.09 mg/g-65.99 mg/g; the drying time is short, and the production cost is saved. The original olive fruit powder provided by the invention can be used as instant olive fruit powder, can be directly eaten, is convenient and sanitary, can be used as a base material of high-grade seasonings or a matching material of cake foods, and has wide application value; meanwhile, the original-taste olive fruit powder prepared by the preparation method can enable the medicine and food dual-purpose function of the olive to be applied more deeply, realize the effective value of functional processed fruits and solve the industrial problems of difficult storage, transportation and preservation of fresh olive fruits, long shelf life, market delay and the like. Is applied to the development of health products, traditional Chinese medicine decoction pieces and other products.

In order to further illustrate the present invention, the following detailed description of the original olive fruit powder and the preparation method thereof provided by the present invention is made with reference to the accompanying drawings and examples, which should not be construed as limiting the scope of the present invention.

Example 1

The preparation process of the original olive fruit powder comprises the following steps:

(1) selecting mature olive fruits which are large and full, have smooth surfaces, no disease spots and no insect eyes and are yellow green in color, and cleaning stains on the surfaces of the olive fruits by water.

(2) Blanching the above olive fruits in boiling water at 95 deg.C for 10s, cooling in warm water bath at 25 deg.C for 25s, and naturally draining for 30min to obtain enzyme-deactivated olive fruits.

(3) And (3) placing the enzyme-inactivated olive fruits in a refrigerator at 6 ℃ for precooling for 5 hours to obtain precooled olive fruits.

(4) Starting the vacuum freeze dryer, carrying out single-layer arrangement on the precooled olive fruits in a drying bin when the temperature of the plate layer reaches-33 ℃, and completing prefreezing when the temperature of the plate layer reaches-50 ℃.

(5) And (3) increasing the temperature of a cold trap to-30 ℃ when the absolute pressure of the vacuum freeze dryer system is 80Pa, carrying out first sublimation drying for 13h, and then carrying out second sublimation drying for 8h at-15 ℃ to obtain primary dried olive fruits.

(6) Adjusting the absolute pressure of a vacuum freeze dryer system to 130Pa, increasing the temperature of a plate layer to 5 ℃, carrying out primary analysis drying on the olive fruits for 6h, then carrying out secondary analysis drying at 16 ℃ for 6h, and carrying out third analysis drying at 30 ℃ for 3h to obtain the dried olive fruits.

(7) Separating olive pulp and fruit stone of the dried olive fruits in a constant temperature dehumidification environment to obtain olive fruit pulp, and crushing the olive fruit pulp into 250-mesh particles to obtain original-taste olive fruit powder.

(8) Vacuum packaging the original olive fruit powder.

Example 2

(5) And (3) after the system absolute pressure of the vacuum freeze dryer is 80Pa, raising the temperature of the cold trap to-27 ℃ for carrying out first sublimation drying for 15h, raising the temperature of the cold trap to-13 ℃ for carrying out second sublimation drying for 7.5h, and obtaining the primary dried olive fruit.

(6) Adjusting the absolute pressure of a vacuum freeze dryer system to 130Pa, increasing the temperature of a plate layer to 5 ℃, carrying out primary analysis drying on the olive fruits for 6h, then increasing the temperature of the plate layer to 16 ℃, carrying out secondary analysis drying for 6h, and carrying out tertiary analysis drying for 3h at 30 ℃ to obtain the dried olive fruits.

(8) Vacuum packaging the original olive fruit powder.

Example 3

(5) And (3) after the system absolute pressure of the vacuum freeze dryer is 80Pa, raising the temperature of the cold trap to-30 ℃ for carrying out first sublimation drying for 13h, raising the temperature of the cold trap to-15 ℃ for carrying out second sublimation drying for 8h, and obtaining the primary dried olive fruit.

(6) Adjusting the absolute pressure of a vacuum freeze dryer system to 130Pa, increasing the temperature of a plate layer to 8 ℃, carrying out primary analysis drying on the olive fruits for 5.5h, then increasing the temperature of the plate layer to 18 ℃, carrying out secondary analysis drying for 5.5h, and carrying out tertiary analysis drying for 2.5h at 33 ℃ to obtain the dried olive fruits.

(8) Vacuum packaging the original olive fruit powder.

Example 4

(2) Blanching the above olive fruits in boiling water at 95 deg.C for 8s, cooling in warm water bath at 25 deg.C for 25s, and naturally draining for 30min to obtain enzyme-deactivated olive fruits.

(8) Vacuum packaging the original olive fruit powder.

Example 5

(3) Starting the vacuum freeze dryer, carrying out single-layer arrangement on the precooled olive fruits in a freeze drying bin when the temperature of the plate layer reaches-33 ℃, and completing prefreezing when the temperature of the plate layer reaches-50 ℃.

(4) And (3) after the system absolute pressure of the vacuum freeze dryer is 80Pa, raising the temperature of the cold trap to-30 ℃ for carrying out first sublimation drying for 13h, raising the temperature of the cold trap to-15 ℃ for carrying out second sublimation drying for 8h, and obtaining the primary dried olive fruit.

(5) Adjusting the absolute pressure of a vacuum freeze dryer system to 130Pa, increasing the temperature of a plate layer to 5 ℃, carrying out primary analysis drying on the olive fruits for 6h, then increasing the temperature of the plate layer to 16 ℃, carrying out secondary analysis drying for 6h, and carrying out tertiary analysis drying for 3h at 30 ℃ to obtain the dried olive fruits.

(6) Separating olive pulp and fruit stone of the dried olive fruits in a constant temperature dehumidification environment to obtain olive fruit pulp, and crushing the olive fruit pulp into 250-mesh particles to obtain original-taste olive fruit powder.

(7) Vacuum packaging the original olive fruit powder.

Comparative example 1

The preparation process of the olive fruit powder comprises the following steps:

(2) Blanching the above olive fruits in boiling water at 95 deg.C for 18s, cooling in warm water bath at 25 deg.C for 25s, and naturally draining for 30min to obtain enzyme-deactivated olive fruits.

(4) Starting the vacuum freeze dryer, carrying out single-layer arrangement on the precooled olive fruits in a freeze drying bin when the temperature of the plate layer reaches-33 ℃, and completing prefreezing when the temperature of the plate layer reaches-50 ℃.

(8) Vacuum packaging the original olive fruit powder.

Comparative example 2

(2) Naturally draining for 30 min.

(8) Vacuum packaging the original olive fruit powder.

Comparative example 3

(5) And (4) after the system absolute pressure of the vacuum freeze dryer is 80Pa, the cold trap is increased to-30 ℃ for drying for 72h, and then the vacuum freeze dryer is taken out.

(7) Vacuum packaging the original olive fruit powder.

Comparative example 4

Cleaning fresh olive, and removing insect and fruit; weighing 10 jin of olive, 1.5 jin of salt and 1 jin of ginger, putting the materials into a mortar, stirring, smashing until no large-particle fruit blocks exist, and simultaneously taking out kernels; putting the crushed fruit pulp into a hot air dryer, drying for 45 hours at 75 ℃ and 2m/s of air speed to keep the water content at 3%; pulverizing fructus Canarii albi pulp into 250 mesh powder, and packaging.

Sensory evaluation is carried out on the olive fruit powder obtained 2 days later, 20 panelists in examples, comparative examples and fresh fruits are selected for tasting, the taste evaluation of the olive fruit powder by the panelists is investigated, the content of total flavonoids is detected, and the result is shown in figure 1 and table 1.

As shown in figure 1, the olive fruit color is observed and recorded immediately after the blanching enzyme-killing treatment (blanching for 10s) of the example 1, and the result is shown as a; comparative example 1 olive fruit color was observed immediately after blanching enzyme-inactivating (blanching for 18s) treatment and the observation was recorded, the results are shown in b. The olive fruit produced by the method provided by the invention is light olive green in color, and the olive fruit treated by blanching and enzyme deactivation for too long time is yellow in color. As can be seen from the above, if the blanching enzyme-inactivating time is appropriate, the color of the fruit is not changed, the time is too long, and the color is changed into yellow.

Table 1 shows the comparison of sensory evaluation, drying time and total flavone content of examples, comparative examples and fresh fruits

As can be seen from Table 1, by comparing the colors of fresh fruits, the olive fruit powders obtained in examples 1 to 5 and the olive fruit powders obtained in comparative examples 1 to 4 through sensory evaluation, it can be seen that the color of the fruit powder product prepared by the invention still has olive green, while the color of the traditional olive product and the product prepared in comparative example 1 has changed; meanwhile, according to the experimental data recorded in the embodiments 1 to 5 in the application, the technical effects of good aftertaste, strong and thick elemi taste, thick and astringent taste can be achieved by adopting the method provided by the application, the drying time is shortest by adopting the preparation method of the embodiment 1, and the total flavone content is highest in the embodiment. And the olive fruits in the comparative example 2 are not subjected to blanching enzyme deactivation treatment, so that the quality guarantee period is obviously shorter than that of the examples 1-5.

The total flavone content and the calcium content of fresh fruits, the olive fruit powder obtained in examples 1-5 and the olive fruit powder obtained in comparative examples 1-4 are detected according to the NY/T2741-2005 'determination of flavonoids in pome fruits-liquid chromatography' standard, and the detection result shows that the total flavone content of the fruit powder prepared by the method is about 4 times of the total flavone content of the fresh fruits in the same amount; and the olive fruit which is not subjected to blanching enzyme deactivation has serious loss of nutrient components. Therefore, the preparation scheme of the invention has great effect on keeping the color, the flavor and the effective components of the fruit powder. In addition, the cost is a key factor for restricting the processing of agricultural products, the sublimation drying and the desorption drying of the vacuum freeze drying are carried out in stages and in sequence, the drying time is shortened to 36h, the time is obviously shortened compared with the direct drying, and the purpose of saving the cost is achieved. Meanwhile, comparison between the embodiment 1 of the invention and the comparative example 1 shows that the enzyme inactivation by blanching in a short time can passivate the enzyme to a certain extent and reduce the loss of the total flavonoids.

Although the present invention has been described in detail with reference to the above embodiments, it is only a part of the embodiments of the present invention, not all of the embodiments, and other embodiments can be obtained without inventive step according to the embodiments, and the embodiments are within the scope of the present invention.

Claims

1. A preparation method of original-taste olive fruit powder comprises the following steps:

2. The preparation method according to claim 1, further comprising a pre-cooling treatment before the vacuum freeze-drying; the temperature of the pre-cooling treatment is 5-8 ℃, and the time is 4-6 h.

3. The preparation method according to claim 1, wherein the blanching enzyme deactivation comprises blanching with boiling water and cooling with warm water which are sequentially carried out; the temperature of the boiling water blanching is 90-95 ℃, and the time is 8-13 s; the temperature of the warm water cooling is 20-25 ℃, and the time is 25-30 s.

4. The method of claim 1, wherein the vacuum freeze-drying comprises prefreezing, sublimation drying and resolution drying which are performed in this order.

5. The method of claim 4, wherein the pre-freezing is initiated at a temperature of-30 ℃ to-35 ℃; the termination temperature of the pre-freezing is-45 ℃ to-50 ℃.

6. The production method according to claim 4, wherein the sublimation drying includes a first sublimation drying and a second sublimation drying which are performed in this order; the temperature of the first sublimation drying is-25 ℃ to-30 ℃, and the time is 10h to 15 h; the temperature of the second sublimation drying is-10 ℃ to-15 ℃, and the time is 7h to 8 h; the sublimation drying is carried out under the vacuum condition, and the absolute pressure of a vacuum system is 80 Pa-100 Pa.

7. The production method according to claim 4, wherein the analytical drying includes a first analytical drying, a second analytical drying, and a third analytical drying which are performed in this order; the temperature of the first analysis drying is 5-10 ℃, and the time is 5-6 h; the temperature of the second analysis drying is 16-20 ℃, and the time is 5-6 h; the temperature of the third analysis drying is 30-35 ℃, and the time is 2-3 h; the analysis and drying are carried out under the vacuum condition, and the absolute pressure of a vacuum system is 130-150 Pa.

8. The preparation method according to claim 1, wherein the denucleation and pulverization manner comprises: separating pulp and kernel of dried olive fruit in a constant temperature dehumidification environment to obtain olive fruit pulp; crushing the olive fruit pulp to obtain original olive fruit powder; the particle size of the original olive fruit powder is 80-300 meshes.

9. The preparation method according to claim 1, wherein the blanching enzyme deactivation comprises a selection and a washing which are carried out in sequence;

the selection mode is as follows: selecting mature olives with large and full grains, smooth surfaces and yellow-green colors, and removing diseased fruit insects;

the cleaning mode is as follows: and (4) finely washing the surfaces of the obtained olive fruits by adopting clear water.

10. The original olive fruit powder obtained by the preparation method according to any one of claims 1 to 9, wherein the total flavone content of the original olive fruit powder is 60mg/g to 66 mg/g.