CN112956577A

CN112956577A - Preparation method of sugar-free probiotic kiwi fruit slices

Info

Publication number: CN112956577A
Application number: CN202110373188.4A
Authority: CN
Inventors: 郜海燕; 刘瑞玲; 陈杭君; 房祥军; 吴伟杰; 韩延超; 穆宏磊
Original assignee: Zhejiang Academy of Agricultural Sciences
Current assignee: Zhejiang Academy of Agricultural Sciences
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2021-06-15
Anticipated expiration: 2041-04-07
Also published as: CN112956577B

Abstract

The invention provides a preparation method of a sugar-free probiotic kiwi fruit tablet. The preparation method of the sugar-free probiotic kiwi fruit tablet provided by the invention comprises the following steps: putting the kiwi fruit slices into sugar-free sugar solution for microwave-ultrasonic synergetic sugar penetration; the power of the microwave is 175-245W, and the time is 30-35 min; the power of the ultrasonic wave is 140-180W, the frequency is 30-50KHz, and the time is 1-2.5 h. According to the preparation method of the sugar-free probiotic kiwi fruit slices, a microwave-ultrasonic wave synergistic sugar permeation mode is adopted, so that the sugar permeation rate of sugar-free sugar liquid permeating into the kiwi fruit slices is improved, and the prepared sugar-free probiotic kiwi fruit slices have the advantages of high sugar content, full preserved fruit body, good sensory quality and high nutritional value.

Description

Preparation method of sugar-free probiotic kiwi fruit slices

Technical Field

The invention belongs to the field of food processing, and relates to a preparation method of a sugar-free probiotic kiwi fruit tablet.

Background

The kiwi fruit is succulent and rich in vitamin C, various amino acids, organic acids, calcium, phosphorus, iron and other mineral elements. In addition, polyphenol, flavonoid, polysaccharide and triterpenes contained in the fruits have the functional effects of resisting inflammation, tumors, aging, improving immunity and the like, so the kiwi fruits have high development and utilization values.

In recent years, kiwi fruits are deeply loved by consumers due to unique flavor and extremely high nutritional value, but the kiwi fruits are thin and juicy, are harvested in high-temperature seasons, are easy to soften and rot after being harvested, and seriously influence the development of related industries. The kiwi fruit is finely processed into kiwi fruit preserved fruit, fruit wine and the like, so that the development and utilization space of the kiwi fruit is widened, and the related industrial chain can be prolonged.

The preserved kiwi fruit tastes sour and sweet, has strong fruit fragrance, but has relatively high sugar content, so that most people who eat healthy food are prohibited. Compared with the traditional product, the low-sugar and sugar-free preserved fruit has the advantages that the sugar content is greatly reduced, the requirement of people on the health of food can be met, but the sugar infiltration difficulty of the low-sugar and sugar-free preserved fruit is high, so that the low-sugar and sugar-free preserved fruit is low in sugar content, shriveled in the preserved fruit body and poor in sensory quality.

Disclosure of Invention

The invention provides a preparation method of a sugar-free probiotic kiwi fruit tablet, which adopts a microwave-ultrasonic wave synergistic sugar permeation mode to improve the sugar permeation rate of sugar-free sugar solution permeating the kiwi fruit tablet, so that the prepared sugar-free probiotic kiwi fruit tablet has high sugar content, full preserved fruit body and good sensory quality.

The invention also provides a sugar-free probiotic kiwi fruit tablet, which is prepared by the preparation method and has the advantages of high sugar content, full preserved fruit and good sensory quality.

The invention provides a preparation method of a sugar-free probiotic kiwi fruit tablet, which comprises the following steps: putting the kiwi fruit slices into sugar-free sugar solution for microwave-ultrasonic synergetic sugar penetration; the power of the microwave is 175-245W, and the time is 30-35 min; the power of the ultrasonic wave is 140-180W, the frequency is 30-50KHz, and the time is 1-2.5 h.

The microwave-ultrasonic wave synergetic sugar penetration used in the invention means that the kiwi fruit pieces are put into sugar-free sugar liquor for microwave treatment and ultrasonic treatment, wherein the microwave treatment and the ultrasonic treatment can be carried out simultaneously by using microwave and ultrasonic wave or can be carried out respectively, and when the microwave treatment and the ultrasonic treatment are carried out respectively, the invention does not limit the sequence of the microwave treatment and the ultrasonic treatment. In one embodiment, the microwave treatment may be performed using a microwave oven, the ultrasonic treatment may be performed using a digitally controlled ultrasonic cleaner, and the simultaneous microwave and ultrasonic treatment may be performed using a microwave-ultrasonic combination reactor.

In the traditional preparation of kiwi fruit slices, sucrose is usually used as a sweetening agent, but excessive intake of sucrose is unfavorable for human health, and cardiovascular diseases, obesity and the like are easily caused. The sugar-free kiwi fruit slices prepared by using the sugar-free sugar liquor to replace cane sugar can meet the requirement of people on healthy drinking, but the sugar-free sugar liquor permeates the kiwi fruit slices, so that the kiwi fruit slices are high in sugar permeation difficulty and low in sugar content, the preserved fruit bodies can be easily shrunken, the water activity in the preserved fruit bodies is increased, and microorganisms are easily bred, so that the kiwi fruit slices are difficult to store.

The invention adopts a microwave-ultrasonic synergetic sugar permeation mode, which is beneficial for sugar-free sugar solution to permeate into the kiwi fruit slices, so that the kiwi fruit slices have higher sugar content, and further have the characteristics of full preserved fruit and good sensory quality. In addition, when the power of the microwave is 175-.

The processing method provided by the invention realizes efficient sugar-permeation treatment of the sugar-free sugar solution of the kiwi fruit slices, improves the taste of the sugar-free kiwi fruit slices, meets the consumer population with special requirements, and meanwhile, takes the nutrient components in the preserved kiwi fruit as key points, reduces the damage of processing treatment on the nutrient components in the preserved kiwi fruit, and maintains the original intention of consumers for eating the preserved kiwi fruit.

Specifically, the preserved kiwi fruit with different characteristics can be obtained by controlling the parameters of the microwave and the ultrasonic wave, so that the requirements of different consumers are further met.

In one embodiment, when the microwave power is 200-220W and the microwave time is 35min, kiwi slices with sugar content of 32% and Vc content of 0.74mg/g can be obtained. The kiwi fruit slices have excellent sensory quality, and the nutrient content of the kiwi fruit slices is not obviously reduced compared with the fresh kiwi fruit slices.

In another specific embodiment, when the power of the ultrasonic wave is 150- & ltSUB & gt 170- & ltSUB & gt W, the frequency is 35-45KHz, and the time is 1.5h, the sugar content of the kiwi fruit slices is up to more than 30%, and the kiwi fruit slices can particularly meet the requirements of sweet consumers.

In the invention, the sugar-free sugar solution comprises the following components in percentage by mass: 24-32% of sugar alcohol and 0.14-0.18% of polysaccharide excipient.

The sugar-free sugar solution can be water except the sugar alcohol and polysaccharide excipient, and the water is harmless to human bodies, can well infiltrate the pulp tissues of the kiwi fruits and is beneficial to the penetration of the sugar alcohol.

Wherein the sugar alcohol is at least one selected from xylitol, sorbitol, maltitol, isomaltitol, and erythritol. The inventor finds in research that when xylitol is used as sugar alcohol, the prepared sugar-free kiwi fruit slices have better sensory quality, probably because the xylitol does not generate Maillard reaction when being heated and is not easy to brown, so that the kiwi fruit slices have bright color and luster, higher transparency and better sensory quality.

In the research, the inventor finds that when the content of the sugar alcohol is less than 24%, the sugar content of the kiwi fruit slices cannot reach 25%, and when the content of the sugar alcohol is in the range of 24-32%, the sugar content of the kiwi fruit slices is more than 25% and shows an upward trend, but when the content of the sugar alcohol is more than 32%, the sugar content of the kiwi fruit slices is increased slightly, and the sensory quality is obviously reduced, because when the content of the sugar alcohol is more than 32%, the kiwi fruit slices are too sweet, so that the taste is not good, and the sensory quality is influenced.

Besides the excellent sensory quality of the kiwi fruit slices can be kept by the penetration of sugar alcohol, the plumpness of the preserved kiwi fruit slices can be increased by 0.14-0.18% of polysaccharide excipient, and the taste of the kiwi fruit slices is not influenced.

The present invention is not limited to the kind of polysaccharide excipient used, and may be selected from one or more of hydrophilic colloid sodium carboxymethyl cellulose (CMC), gelatin, pectin, xanthan gum, sodium alginate, konjac gum, carrageenan, for example.

In the research of the inventor, the inventor finds that when the selected polysaccharide excipient comprises CMC and pectin, and the mass ratio of the CMC to the pectin is 1:1, the prepared kiwi fruit slices have good plumpness and good mouthfeel.

In a specific embodiment, after putting the kiwi fruit pieces into sugar-free sugar solution for microwave-ultrasonic wave synergetic sugar penetration, the method further comprises the following steps: spraying probiotic seasoning powder on the surface of the sugar-permeated kiwi fruit slices.

The probiotics can maintain and improve the microbial balance of intestinal canal media, promote the digestion and absorption of nutrient substances in vivo, and the addition of the probiotics seasoning powder in the preparation of the preserved kiwi fruit can improve the nutritional value of the preserved kiwi fruit. However, most probiotics in the market, such as lactobacillus bulgaricus, streptococcus thermophilus and the like, are not high-temperature resistant and are difficult to survive in processing and baking of the sugar-free probiotic kiwi fruit slices, and bacillus coagulans belongs to high-temperature probiotics and can survive in the processing process of the sugar-free probiotic kiwi fruit slices such as microwave and baking.

The inventor finds that the probiotic seasoning powder comprises the following components in parts by weight: 4-12 parts of sugar alcohol, 1-5 parts of yoghurt powder, 0.1-0.5 part of DL-malic acid and 0.05-0.25 part of bacillus coagulans, the prepared sugar-free probiotic kiwi fruit tablets can help nutrient substances to be digested and absorbed in vivo.

The kiwi fruit slices are dried after sugar infiltration to remove partial moisture, so that the prepared sugar-free probiotic kiwi fruit slices have dry and comfortable surfaces, are not sticky and are beneficial to preservation.

In a specific embodiment, the drying treatment comprises drying the kiwifruit pieces sprayed with the probiotic seasoning powder at 70-80 ℃ until the moisture content of the kiwifruit pieces is 18-20%.

In another specific embodiment, the drying treatment comprises pre-drying the sugar-infiltrated kiwi fruit slices at 50-60 ℃ until the water content of the kiwi fruit slices is 50%, spraying probiotic seasoning powder on the surfaces of the kiwi fruit slices, heating to 70-80 ℃, and continuously drying until the water content of the kiwi fruit slices is 18-20%. The kiwi fruit slices can be heated more uniformly by stage heating and drying, and the prepared sugar-free probiotic kiwi fruit slices have no cracking phenomenon on the surface and the edge and good plumpness.

During the drying treatment process of the kiwi fruit slices, the kiwi fruit slices can be turned over at intervals to be heated uniformly.

To further enhance the sugar-exuding effect, the kiwi fruit pieces can be frozen at-18 deg.C for 2h before sugar-exuding, and then warmed to room temperature. The kiwi fruit slices are frozen at-18 ℃ for 2h and then heated to room temperature, so that free water in the kiwi fruit slices can form ice crystals to destroy the internal structure of the kiwi fruit slices, a large number of gaps and channels are formed, sugar-free sugar liquid can permeate into the kiwi fruit slices, and a better sugar permeation effect is achieved.

It can be understood that the kiwi fruit slices can be subjected to the jointing treatment to obtain a better sugar permeation effect, when the jointing direction is along the fruit equator direction, the jointing depth is 0.1-1mm, and the jointing interval is 3-5mm, the contact area between the kiwi fruit slices and the sugar-free sugar solution is greatly increased, and the sugar-free sugar solution is more favorably permeated into the kiwi fruit slices.

The maturity and thickness of the kiwi fruit slices, the color protection technology and the hardening technology are also important factors influencing the sensory quality of the sugar-free probiotic kiwi fruit slices.

The ripeness is too high, and the kiwi fruit slices are too soft to be formed; if the ripeness is too low, the taste is not good. Similarly, the thickness of the kiwi fruit slices is too large, which is not beneficial to the penetration of sugar liquid; the small thickness of the kiwi fruit pieces is not favorable for forming. According to the invention, fresh kiwi fruits with the maturity of seven to eight ripeness are adopted and sliced, the slicing thickness is 8-10mm, and the sugar-free probiotic kiwi fruit slices can obtain better sensory quality.

According to the invention, the adopted color protection liquid comprises 0.4% of citric acid, 0.2% of ascorbic acid and the balance of water by mass percent, and the kiwi fruit slices thawed to room temperature are immersed in the color protection liquid for color protection treatment for 2 hours, so that browning reaction of the kiwi fruit slices can be effectively avoided, and the prepared sugar-free probiotic kiwi fruit slices have bright color.

The hardening liquid adopted by the invention is a calcium chloride aqueous solution with the mass fraction of 0.1%, and the kiwi fruit slices with the color protection are immersed in the hardening liquid for hardening treatment for 1-2h, so that the pulp hardness of the kiwi fruit slices can be improved, and the kiwi fruit slices are prevented from being soft and rotten in the subsequent processing and difficult to form.

It can be understood that, besides the pretreatment, the method also comprises the steps of cleaning the kiwi fruits, and sequentially carrying out operations of peeling, freezing, color protection, hardening, slitting, sugar permeation, drying and the like on the kiwi fruits according to the requirements after cleaning, so as to obtain the sugar-free probiotic kiwi fruit slices.

The second aspect of the invention provides a sugar-free probiotic kiwi fruit tablet, which is obtained by the preparation method provided by the first aspect of the invention, so that the sugar-free probiotic kiwi fruit tablet has the advantages of high sugar content, full preserved fruit body and good sensory quality.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the preparation method of the sugar-free probiotic kiwi fruit slices, a microwave-ultrasonic wave synergistic sugar permeation mode is adopted, so that the sugar permeation rate of sugar-free sugar liquid permeating the kiwi fruit slices is improved, and the prepared sugar-free probiotic kiwi fruit slices have the advantages of high sugar content, full preserved fruit body and good sensory quality.

2. According to the preparation method of the sugar-free probiotic kiwi fruit slices, a microwave-ultrasonic wave synergetic sugar permeation mode is adopted, and the power, frequency and time of single microwave and ultrasonic wave sugar permeation are reduced, so that the damage degree of nutritional component vitamin C in kiwi fruit pulp is reduced, and the prepared sugar-free probiotic kiwi fruit slices have high nutritional value.

3. The sugar-free probiotic kiwi fruit slices provided by the invention have the advantages of high sugar content, full preserved fruit body, good sensory quality and high nutritional value.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The preparation method of the sugar-free probiotic kiwi fruit tablet comprises the following steps:

1) selecting kiwi fruit slices with the maturity of eighty percent, cleaning, peeling, and cutting into kiwi fruit slices with the thickness of 9 mm;

2) freezing kiwi fruit slices at-18 ℃ for 2h, slowly thawing to room temperature, protecting color in a color protection solution for 2h, and hardening the kiwi fruit slices in a hardening solution for 1.5h after color protection;

the color protection liquid comprises 0.4 percent of citric acid, 0.2 percent of ascorbic acid and the balance of water by mass percent;

the hardening liquid is a calcium chloride aqueous solution with the mass fraction of 0.1%.

3) And (3) slitting the hardened kiwi fruit slices along the equator direction of the fruit, wherein the slitting depth is 0.5mm, and the interval of each slit is 4 mm.

4) Putting the sewn kiwi fruit slices in a sugar-free sugar solution for microwave-ultrasonic wave synergetic sugar permeation, wherein the microwave sugar permeation power is 210W, and the time is 35 min; the ultrasonic wave sugar permeability power is 160W, the frequency is 40KHz, and the time is 1.5 h.

The sugar-free sugar solution comprises 28 mass percent of xylitol, 0.16 mass percent of polysaccharide excipient and the balance of water, wherein the polysaccharide excipient is a compound of CMC and pectin in a mass ratio of 1: 1.

5) Taking out kiwi fruit slices from the sugar-free sugar solution, putting the kiwi fruit slices with the sugar-free sugar solution on the surface removed into a forced air drying oven, drying at 55 ℃ until the water content of the kiwi fruit slices is 50%, taking out, uniformly spraying probiotic seasoning powder, and continuously putting into the forced air drying oven, drying at 75 ℃ until the water content of the kiwi fruit slices is 20%, thus obtaining the sugar-free probiotic kiwi fruit slices;

the probiotic seasoning powder comprises the following components in parts by weight: 4 parts of xylitol, 1 part of yoghurt powder, 0.1 part of DL-malic acid and 0.1 part of bacillus coagulans.

Example 2

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 3), the ultrasonic time is 1 h.

Example 3

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 3), the ultrasonic time is 2 hours.

Example 4

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 3), the ultrasonic time is 2.5 h.

Example 5

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the mass percentage content of xylitol in the sugar-free sugar solution is 20%.

Example 6

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the mass percentage content of xylitol in the sugar-free sugar solution is 24%.

Example 7

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the mass percentage of xylitol in the sugar-free sugar solution is 32%.

Example 8

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the mass percentage of xylitol in the sugar-free sugar solution is 36%.

Example 9

The preparation method of the sugar-free probiotic kiwi fruit tablet of the embodiment is basically the same as that of the embodiment 1, except that in the step 4), the mass percentage of the polysaccharide excipient is 0.12%.

Example 10

The preparation method of the sugar-free probiotic kiwi fruit tablet of the embodiment is basically the same as that of the embodiment 1, except that in the step 4), the mass percentage of the polysaccharide excipient is 0.14%.

Example 11

The preparation method of the sugar-free probiotic kiwi fruit tablet of the embodiment is basically the same as that of the embodiment 1, except that in the step 4), the mass percentage of the polysaccharide excipient is 0.18%.

Example 12

The preparation method of the sugar-free probiotic kiwi fruit tablet of the embodiment is basically the same as that of the embodiment 1, except that in the step 4), the mass percentage of the polysaccharide excipient is 0.20%.

Example 13

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the polysaccharide excipient is a compound of CMC and pectin in a mass ratio of 3: 1.

Example 14

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the polysaccharide excipient is a compound of CMC and pectin in a mass ratio of 2: 1.

Example 15

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the polysaccharide excipient is a compound of CMC and pectin in a mass ratio of 1: 2.

Example 16

The preparation method of the sugar-free probiotic kiwi fruit tablet in the embodiment is basically the same as that in the embodiment 1, except that in the step 4), the polysaccharide excipient is a compound of CMC and pectin in a mass ratio of 1: 3.

Example 17

The preparation method of the sugar-free probiotic kiwi fruit slices in the embodiment is basically the same as that in the embodiment 1, except that in the step 5), probiotic seasoning powder is sprayed on the kiwi fruit slices with sugar-free sugar liquid on the surface being drained, and then the kiwi fruit slices are placed into a blast drying oven to be dried at 75 ℃ until the water content of the kiwi fruit slices is 20%.

Comparative example 1

The preparation method of the sugar-free probiotic kiwi fruit tablet in the comparative example is basically the same as that in example 1, except that only microwave sugar permeation is adopted in the step 4), the sugar permeation power is 210W, and the sugar permeation time is 125 min.

Comparative example 2

The preparation method of the sugar-free probiotic kiwi fruit tablet in the comparative example is basically the same as that in the example 1, except that in the step 4), only ultrasonic sugar permeation is adopted, the sugar permeation power is 160W, the frequency is 40KHz, and the time is 125 min.

Comparative example 3

The preparation method of the sugar-free probiotic kiwi fruit tablet of the comparative example is basically the same as that of example 1, except that in the step 4), the sugar permeation time of the ultrasonic wave is 0.5 h.

Comparative example 4

The preparation method of the sugar-free probiotic kiwi fruit tablet of the comparative example is basically the same as that of example 1, except that in the step 4), the microwave power is 270W.

Comparative example 5

The preparation method of the sugar-free probiotic kiwi fruit tablet of the comparative example is basically the same as that of example 1, except that in the step 4), the power of ultrasonic wave is 200W.

Comparative example 6

The preparation method of the sugar-free probiotic kiwi fruit tablet of the comparative example is basically the same as that of example 1, except that in the step 4), the frequency of the ultrasonic wave is 80 KHz.

Test examples

1. Sugar content and sensory quality testing

The sugar-free probiotic kiwi fruit tablets of examples 1-8, 17 and comparative examples 1-6 were tested for sugar content and sensory quality, wherein the method for testing sugar content refers to anthrone sulfuric acid colorimetry, and the sensory quality test refers to NY/T436-2009 standard to establish a sensory evaluation table specifically for the sugar-free probiotic kiwi fruit tablets of the present invention, see table 1. The results of the sugar content and sensory quality tests are shown in table 2.

TABLE 1

TABLE 2

	Sugar content	Sensory evaluation
			Example 1	34.31％	82.5 points
Example 2	27.30％	67.9 points
			Example 3	29.04％	81.4 points
Example 4	28.29％	78.2 points
			Example 5	22.62％	65.1 points
Example 6	29.34％	71.2 points
			Example 7	33.41％	82.3 points
Example 8	34.74％	72.3 points
			Example 17	33.46％	80.7 points
Comparative example 1	25.02％	57.0 point
			Comparative example 2	24.18％	66.0 point
Comparative example 3	21.23％	64.0 min
			Comparative example 4	24.12％	62.0 point
Comparative example 5	25.34％	61.0 point
			Comparative example 6	23.41％	59.0 min

From the data of table 2, the following conclusions can be drawn:

a. it can be seen from the comparison of examples 1-4 and comparative example 3 that the fixed microwave time is not changed, the sugar content and the sensory quality of the product show a trend of increasing and then decreasing along with the prolonging of the ultrasonic time, when the microwave time in the microwave-ultrasonic synergetic sugar permeation is 35min and the ultrasonic time is 1.5h, the sugar content of the sugar-free probiotic kiwi fruit tablet is the highest, the sensory quality is the best, and when the ultrasonic time is only 0.5h, the sugar content of the sugar-free probiotic kiwi fruit tablet is only 21.23%.

b. It can be seen from comparison between example 1 and examples 5-8 that the addition amount of xylitol in the sugar-free sugar solution has a significant effect on the sugar content and the sensory quality of the sugar-free probiotic kiwi fruit tablets, the sugar content gradually increases with the increase of the addition amount of xylitol, when the addition amount of xylitol reaches 32%, the increase of the sugar content is gradually slowed down, and the increase is not obvious, so that the sugar infiltration difficulty of the sugar-free probiotic kiwi fruit tablets is reflected to be high, and after the addition amount of xylitol reaches 32%, the sweetness of the sugar-free probiotic kiwi fruit tablets is too high, so that the taste is not good, and the sensory quality is also reduced.

c. It can be seen by comparing example 1 with example 17 that the sugar content of the sugar-free probiotic kiwi fruit tablet is not significantly affected by adopting the staged temperature rising drying mode, but the sensory quality of the sugar-free probiotic kiwi fruit tablet can be better by the staged temperature rising drying mode.

d. It can be seen from the comparison of example 1, comparative example 1 and comparative example 2 that the sugar content and sensory quality of the sugar-free probiotic kiwi fruit tablets prepared by adopting the microwave-ultrasonic wave synergetic sugar permeation mode are obviously superior to those of the sugar-free probiotic kiwi fruit tablets prepared by single microwave or ultrasonic wave sugar permeation under the same sugar permeation power and sugar permeation time.

e. It can be seen from the comparison of example 1 with comparative examples 4 to 6 that when the power of the microwave, the power of the ultrasonic wave and the frequency of the ultrasonic wave are not in proper ranges, the prepared sugar-free probiotic kiwi fruit tablets cannot have higher sugar content and more excellent sensory quality.

3. Candied body plumpness index test

The sugar-free probiotic kiwi fruit tablets of examples 1 and 9-16 were tested for the breast fullness index by the following test methods: and (3) expressing the plumpness of the samples by using the volume ratio before and after drying, and calculating the plumpness index of each sample by using the plumpness of the high-sugar preserved kiwi fruits as a reference.

Fullness A ═ V₂/V₁×100％ (1)

The satiation index B is A₂/A₁×100％ (2)

In the formula V₁-volume of preserved kiwi fruit before drying, mL; v₂Volume of dried preserved kiwi fruit product, mL; a. the₁-50% sugar liquor preparation of high sugar candied kiwi fruit fullness,%; a. the₂-fullness of finished kiwifruit products prepared by different processes,%. The test results are shown in table 3.

TABLE 3

As can be seen from table 3, when the addition amount of the polysaccharide excipient is 0.16%, the fullness index of the sugar-free probiotic kiwi fruit slices is highest; with the increase of the pectin amount, the fullness index of the sugar-free probiotic kiwi fruit slices shows a trend of rising first and then falling, wherein when the mass ratio of the CMC to the pectin reaches 1:1, the fullness index of the sugar-free probiotic kiwi fruit slices is the highest.

4. Vc content test

The Vc content of the sugar-free probiotic kiwi fruit tablets of example 1, comparative example 1 and comparative example 2 was tested on a fresh kiwi fruit (fresh sample) with eight ripeness degrees in raw state, the test method being: 1g of sample was weighed out accurately, and 5.0mL of 5% trichloroacetic acid (TCA) was added. Mixing, centrifuging, collecting supernatant 0.4mL, adding 5% TCA 1.6mL, anhydrous ethanol 1mL, 0.5mL 0.5% phosphoric acid-ethanol, 0.5mL 0.5% o-phenanthroline-ethanol 1.0mL, and 0.03% FeCl 0.5mL₃-ethanol, measuring OD534 nm after 30 ℃ water bath for 60min, repeating for three times, and calculating Vc content according to a standard curve, wherein the unit is mg/g. The test results are shown in table 4.

TABLE 4

	Fresh sample	Example 1	Comparison ofExample 1	Comparative example 2
					Vc content (mg/g)	0.85	0.74	0.56	0.70

As can be seen from Table 4, compared with the fresh samples, the Vc is damaged to a greater extent by adopting the single microwave sugar infiltration mode and the single ultrasonic sugar infiltration mode, and the Vc content of the microwave-ultrasonic wave synergistic sugar infiltration mode is kept to the highest extent, which indicates that the sugar-free probiotic kiwi fruit tablets obtained by the microwave-ultrasonic wave synergistic sugar infiltration mode provided by the invention have higher nutritional value.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of sugar-free probiotic kiwi fruit slices is characterized by comprising the following steps: putting the kiwi fruit slices into sugar-free sugar solution for microwave-ultrasonic synergetic sugar penetration;

the power of the microwave is 175-245W, and the time is 30-35 min;

the power of the ultrasonic wave is 140-180W, the frequency is 30-50KHz, and the time is 1-2.5 h.

2. The method as claimed in claim 1, wherein the power of the microwave is 200-220W and the time is 35 min.

3. The method as claimed in claim 2, wherein the power of the ultrasonic wave is 150-170W, the frequency is 35-45KHz, and the time is 1.5 h.

4. The preparation method of claim 1, wherein the sugar-free sugar solution comprises the following components in percentage by mass: 24-32% of sugar alcohol and 0.14-0.18% of polysaccharide excipient.

5. The preparation method according to claim 1, wherein after putting the kiwi fruit pieces into sugar-free sugar solution for microwave-ultrasonic wave synergistic sugar penetration, the method further comprises: spraying probiotic seasoning powder on the surface of the sugar-permeated kiwi fruit slices;

the probiotic seasoning powder comprises the following components in parts by weight: 4-12 parts of sugar alcohol, 1-5 parts of yoghurt powder, 0.1-0.5 part of DL-malic acid and 0.05-0.25 part of bacillus coagulans.

6. The preparation method according to claim 5, wherein the kiwi fruit slices sprayed with the probiotic seasoning powder are dried until the water content of the kiwi fruit slices is 18-20%, and the temperature of the drying process is 70-80 ℃.

7. The preparation method of claim 6, wherein before spraying the probiotic seasoning powder on the surface of the sugar-permeated kiwi fruit slice, the method further comprises pre-drying the sugar-permeated kiwi fruit slice until the water content of the kiwi fruit slice is 50%, wherein the pre-drying temperature is 50-60 ℃.

8. The method of claim 1, wherein the kiwi pieces are frozen at-18 ℃ for 2 hours and then warmed to room temperature before sugar leakage.

9. The preparation method according to claim 1, wherein the kiwi fruit slices are subjected to a scoring treatment, wherein the scoring direction is along the equator direction of the fruit, the scoring depth is 0.5-1mm, and the scoring interval is 3-5 mm.

10. Sugar-free probiotic kiwi fruit tablet, characterized in that it is obtained according to the preparation method of any one of claims 1-9.