CN116725166B - A sweet potato food product and its preparation method - Google Patents

Abstract

This invention relates to the field of food processing, specifically to a sweet potato food product and its preparation method. The method involves steaming sweet potatoes to a semi-cooked state using a short-time vacuum low-temperature cooking process, followed by the addition of egg yolks to alter the acidity/alkalinity of the sweet potatoes. This provides an environment conducive to the fermentation of high-sugar-tolerant dry yeast while maintaining the product's sensory characteristics. Simultaneously, the enzymes in the sweet potatoes and egg yolks enhance the degradation of macromolecules in the fermentation system, satisfying the nutritional needs of the high-sugar-tolerant dry yeast during fermentation and promoting its reproduction. This, in turn, leads to the production of more carbon dioxide, increasing the puffing degree of the sweet potato food. Compared to existing technologies, this method avoids the excessive addition of food additives, solving the problem of product quality degradation caused by food additives. While ensuring product quality, it achieves the puffing effect of adding chemical compound puffing agents.

Description

Sweet potato food and preparation method thereof

Technical Field

The invention relates to the field of foods, in particular to a sweet potato food and a preparation method thereof.

Background

The sweet potato food is an expanded food prepared by taking sweet potatoes as a main raw material and adopting the processes of cooking, curing, drying, frying and the like, is golden and crisp, accords with the preference of consumers, has the problem of low expansion degree and further influences the edible taste.

In order to solve the problems, the prior art generally increases the puffing degree of food by adding a food puffing agent. The existing food bulking agents are generally divided into two types, namely chemical bulking agents and biological bulking agents, and the chemical bulking agents are good in bulking effect but do not meet the requirements of healthy products, so that the existing research is multi-directional, more green and healthy biological bulking agents. The most common biological bulking agent at present is yeast, which achieves the bulking effect by producing gas through fermentation. However, on one hand, the yeast has long puffing time, the puffing effect is inferior to that of a chemical puffing agent, and on the other hand, the steamed sweet potato is alkaline, and the yeast is suitable for a weak acid or neutral living environment, and the alkaline environment can inhibit or even kill the production of the yeast. Therefore, the method is not suitable for puffing sweet potato foods prepared by taking sweet potatoes as raw materials.

Disclosure of Invention

Based on the problems, the invention provides the sweet potato food and the preparation method thereof, and the sweet potato food is prepared by adding the egg yolk and the high sugar-resistant dry yeast for fermentation after low-temperature cooking, so that the fermentation efficiency of the high sugar-resistant dry yeast is improved while the quality of the product is maintained, and the puffing degree of the product is further improved.

The invention provides a sweet potato food and a preparation method thereof, and the preparation method comprises the following specific steps:

s1, preprocessing sweet potatoes by low-temperature cooking to obtain a first material;

S2, adding egg yolk and high sugar-resistant dry yeast into the first material, and fermenting at a constant temperature to obtain a second material;

s3, adding glutinous rice flour into the material II, and drying for the second time to obtain a material III;

S4, carrying out vacuum low-temperature frying treatment on the material III to obtain a finished product.

Further, the low-temperature cooking temperature is 50-55 ℃ and the time is 6-8min.

Further, the high sugar-tolerant dry yeast is activated in warm water at 35 ℃ for 12min before use.

Further, the adding amount of the first material, the egg yolk and the high sugar-resistant dry yeast is 5 (1-1.2) in mass ratio of (0.04-0.06).

Further, the constant temperature fermentation temperature is 32-35 ℃ and the fermentation time is 40-45h.

Further, the adding amount of the second material and the glutinous rice flour is5 (1-1.5) in mass ratio.

Further, the secondary drying is carried out until the moisture content of the material is 8%.

Further, the vacuum low-temperature frying temperature is 90-95 ℃ and the time is 30-35min.

Further, the frying process also comprises seasoning and packaging.

The beneficial effects of the invention are as follows:

According to the application, the sweet potato is subjected to short-time low-temperature cooking treatment, so that enzymes in the sweet potato are partially reserved while the sweet potato is cooked, and then the egg yolk is added. On the one hand, the addition of the egg yolk changes the acidity and alkalinity of the sweet potato and provides a proper environment for the growth of the yeast, and on the other hand, the enzyme in the egg yolk can also cooperate with the enzyme in the sweet potato to enhance the degradation of macromolecular proteins and saccharides in the sweet potato and provide nutrition for the fermentation of the yeast, so that the quick propagation of the yeast is realized, and more carbon dioxide gas is generated by metabolism, thereby improving the puffing degree of the sweet potato food. Compared with the prior art, the puffing degree of the sweet potato food prepared by the application can reach 280-290%.

The application changes the acidity and alkalinity of the mashed sweet potato by adding the egg yolk serving as an acidic food, and endows the sweet potato food with the yolk flavor. Compared with the prior art that acid regulators such as citric acid, malic acid and the like are directly added, the application has coordinated acidity, the problem that the product becomes acid obviously does not occur, and the integral flavor of the product is improved.

Detailed Description

The scheme of the present invention will be explained below with reference to examples. It will be appreciated by those skilled in the art that the following examples are illustrative of the present invention and should not be construed as limiting the scope of the invention. The examples are not to be construed as limiting the specific techniques or conditions described in the literature in this field or as per the specifications of the product. The apparatus used did not identify the manufacturer and was a conventional product commercially available.

The invention provides a sweet potato food and a preparation method thereof, and the preparation method comprises the following specific steps:

s1, preprocessing sweet potatoes by low-temperature cooking to obtain a first material;

S2, adding egg yolk and high sugar-resistant dry yeast into the first material, and fermenting at a constant temperature to obtain a second material;

s3, adding glutinous rice flour into the material II, and drying in two stages to obtain a material III;

S4, carrying out vacuum low-temperature frying treatment on the material III to obtain a finished product.

In the embodiment of the application, the pretreated sweet potato is prepared by selecting sweet potato with no spots, no mildew and no damage, washing the sweet potato with clear water until no sediment is visible to naked eyes, removing the epidermis, cutting the sweet potato into blocks with the size of 1cm multiplied by 1cm, and vacuum packaging.

In the embodiment of the application, the low-temperature cooking temperature is 50-55 ℃ and the time is 6-8min.

In the embodiment of the application, the purpose of vacuum packaging sweet potatoes and then short-time low-temperature cooking is to avoid the enzyme in the sweet potatoes from being consumed or deactivated in a large amount in the high-temperature long-time cooking process, and to provide the enzyme for the post-fermentation process. The temperature of the cooking is 50-55 ℃ and the time is 6-8min, and most enzymes in the sweet potato are destroyed above the temperature and the time, so that the enzymes cannot play a role in the subsequent fermentation process.

In some specific embodiments, the first material after low-temperature steaming is in a mud shape, namely sweet potato mud, and the adding ratio of the first material to the egg yolk to the high sugar-resistant dry yeast is 5 (1-1.2) (0.04-0.06) in parts by weight.

In the embodiment of the application, the high sugar-resistant dry yeast is yeast which still has higher activity in the raw material with the sugar content of more than 25 percent, and the high sugar-resistant dry yeast is purchased from Angel yeast Co.

In the embodiment of the application, the high sugar-tolerant dry yeast is activated in warm water at 32 ℃ for 12min before being used.

In the embodiment of the application, the fermentation temperature is 32-35 ℃ and the fermentation time is 4-5h.

According to the embodiment of the application, the addition of the acid food egg yolk solves the problem of obvious sour taste of the sweet potato food product caused by the addition of the acid regulator, endows the sweet potato food egg yolk with flavor and ensures the organoleptic properties of the product, and on the other hand, supplements enzymes for a subsequent fermentation system, cooperates with enzymes in sweet potatoes, enhances the degradation of macromolecules in the fermentation system, satisfies the nutrition supply in the fermentation process of the high sugar dry yeast, promotes the propagation of the high sugar dry yeast, further generates more carbon dioxide by metabolism, and improves the puffing degree of the sweet potato food.

In the prior art, acidity regulators such as citric acid and malic acid are added to change the acidity and alkalinity of sweet potatoes steamed at high temperature to obtain conditions suitable for fermentation of saccharomycetes, and then enzyme preparations are added to compound with saccharomycetes to promote the proliferation and metabolism of saccharomycetes, so that the puffing efficiency of products is improved.

In some specific embodiments, the second material obtained by fermentation is in a pasty state, namely sweet potato pulp, and the second material and the glutinous rice flour are added in a proportion of 5 (1-1.5) by weight.

In some specific embodiments, in the secondary drying process, the primary drying temperature is 65 ℃, the drying time is 3-5h, and the secondary drying temperature is 75 ℃ and the drying time is 4-6h.

In some embodiments, the moisture content of the secondarily dried material is 8%.

In some specific embodiments, the vacuum low temperature frying is carried out by adopting a vacuum low temperature frying machine, controlling the oil temperature to be 90-95 ℃, and controlling the vacuum degree to be 0.09-0.095 Mpa for 30-35min.

In some embodiments, the vacuum low temperature frying process is followed by seasoning and packaging.

Example 1 sweet potato food was prepared:

(1) Selecting sweet potato with no spots, no mildew or damage, cleaning with clear water until no sediment is visible to naked eyes, removing epidermis, cutting into blocks of 1cm×1cm, and vacuum packaging;

(2) Steaming the pretreated sweet potato at 55 ℃ for 6min, and mashing to obtain a first material;

(3) Adding 24kg of egg yolk and 0.12kg of high sugar-resistant dry yeast activated in warm water at 32 ℃ for 12min into each 100kg of material I for fermentation, and controlling the fermentation temperature at 35 ℃ for 4h to obtain a material II;

(4) Adding 30kg of glutinous rice flour into each 100kg of the second material, fully mixing, curing and forming, drying by adopting a secondary drying method, wherein the primary drying temperature is 65 ℃, the drying time is 5 hours, the secondary drying temperature is 75 ℃, and the drying time is 4 hours, and drying until the moisture content is 8%, thereby obtaining a third material;

(5) And (3) placing the third material in a vacuum frying machine, and frying for 30min under the condition that the oil temperature is 95 ℃ and the vacuum degree is-0.09 Mpa, thus obtaining the finished sweet potato food.

Example 2 sweet potato food was prepared:

(1) Selecting sweet potato with no spots, no mildew or damage, cleaning with clear water until no sediment is visible to naked eyes, removing epidermis, cutting into blocks of 1cm×1cm, and vacuum packaging;

(2) Steaming the pretreated sweet potato at a low temperature of 52 ℃ for 7min, and mashing to obtain a first material;

(3) Adding 22kg of egg yolk and 0.1kg of high sugar-resistant dry yeast activated in warm water at 32 ℃ for 12min into each 100kg of material I for fermentation, and controlling the fermentation temperature at 32 ℃ for 4.5h to obtain a material II;

(4) Adding 25kg of glutinous rice flour into each 100kg of the second material, fully mixing, curing and forming, drying by adopting a secondary drying method, wherein the primary drying temperature is 65 ℃, the drying time is 4 hours, the secondary drying temperature is 75 ℃, and the drying time is 5 hours, and drying until the moisture content is 8%, thereby obtaining a third material;

(5) And (3) placing the third material in a vacuum frying machine, frying for 32 minutes under the condition that the oil temperature is 93 ℃ and the vacuum degree is-0.092 Mpa, and packaging after seasoning to obtain the finished sweet potato food.

Example 3 sweet potato food was prepared:

(1) Selecting sweet potato with no spots, no mildew or damage, cleaning with clear water until no sediment is visible to naked eyes, removing epidermis, cutting into blocks of 1cm×1cm, and vacuum packaging;

(2) Steaming the pretreated sweet potato at 50 ℃ for 8min, and mashing to obtain a first material;

(3) Adding 20kg of egg yolk and 0.08kg of high sugar-resistant dry yeast activated in warm water at 32 ℃ for 12min into each 100kg of material I for fermentation, and controlling the fermentation temperature at 30 ℃ for fermentation for 5h to obtain a material II;

(4) Adding 20kg of glutinous rice flour into each 100kg of the second material, fully mixing, curing and forming, drying by adopting a secondary drying method, wherein the primary drying temperature is 65 ℃, the drying time is 3 hours, the secondary drying temperature is 75 ℃, and the drying time is 6 hours, and drying until the moisture content is 8%, thus obtaining a third material;

(5) And (3) placing the third material in a vacuum frying machine, frying for 35min under the condition that the oil temperature is 90 ℃ and the vacuum degree is-0.095 Mpa, and packaging after seasoning to obtain the finished sweet potato food.

Comparative example 1 sweet potato food was prepared:

The procedure is as in example 1, except that the yolk and the high sugar dry yeast are not added in comparative example 1.

Comparative example 2 preparation of sweet potato food

The method is the same as in example 1, and compared with example 1, the method is different in that in comparative example 2, the chemical compound bulking agent is adopted to replace egg yolk and high sugar dry yeast, and the chemical compound bulking agent is added according to the mass ratio of 1:0.003.

Comparative example 3 preparation of sweet potato food

The method is the same as in example 1, and is different from example 1 in that the sweet potato is cooked by adopting a high-temperature cooking process in comparative example 3, wherein the temperature of the high-temperature cooking process is 100 ℃ and the time is 6min.

Comparative example 4 preparation of sweet potato food

The method is the same as in example 1, except that the eggs Huang Tihuan are citric acid in comparative example 4.

Test example 1 puffing degree measurement

The degree of puffing is an important indicator for measuring the quality of a fried product, and directly affects the texture and mouthfeel of the fried food.

The test method is that the volume expansion rate is used for expressing the expansion degree. The measurement of the volume of the material adopts a filling method. The method comprises the steps of weighing 20g of sample before frying, putting the sample into a 1000mL measuring cylinder, filling the sample with millet, measuring the volume V0, weighing 20g of sample after vacuum frying, putting the sample into the measuring cylinder, and measuring the volume V1, wherein the puffing degree is calculated according to the following formula:

The experimental results show that the puffing degree measurement results are shown in table 1, the puffing degree of each of the examples 1-3 is higher and is more than 280%, the puffing degree of the example 1-3 is lower than that of the example 1-3, the puffing degree of the example 1-3 is obviously improved, the puffing degree of the example 1-3 is slightly different from that of the example 2-3, the puffing degree of the example 1-3 is slightly different, the puffing effect of the chemical puffing agent can be achieved, the puffing degree of the product can be ensured, the safety performance of the product can be improved, the puffing degree of the example 3-4 is lower than that of the example 1-3, the puffing effect of enzyme in the example 1-3 and the example 4-4 is slightly improved compared with that of the example 1-4 is slightly improved, the puffing effect of the enzyme in the sweet potato or egg yolk alone is slightly improved, the puffing effect of the sweet potato or egg yolk resisting the high sugar dry yeast is obviously improved.

TABLE 1 results of measurement of puffing degree

。

Test example 2 sensory evaluation

Sensory evaluation indexes (such as tissue state, color, flavor, taste and the like) are important indexes for evaluating the quality of the fried products, and the quality of sweet potato foods can be analyzed through sensory scores.

Sensory evaluation method the sweet potato foods obtained in examples 1-3 and comparative examples 1-3 were placed in a disposable paper tray, samples were randomly numbered according to 3 digits, 10 panelists (5 men 5 women, age between 25-45) with food professional background and trained in professional sensory training were selected to form an evaluation panel, and 6 products were sensory scored in terms of 4 aspects of organization state, color, flavor, and taste. The sensory evaluation panelists objectively and independently score, the evaluation interval of each sample is 3-5min, clear water is used for rinsing mouth before each sample is evaluated, the scoring of all the panelists is counted, the score is averaged, and the specific scoring standard is shown in table 2.

Table 2 sweet potato food sensory evaluation criteria

。

The experimental results show that the sensory scores of the examples 1-3 are similar and are over 96 minutes, which shows that the sweet potato food prepared by the process method has good sensory characteristics, the example 1 is higher than the comparative example 1 in score, which shows that the process method can improve the overall quality of the sweet potato food product obviously, the example 1 is slightly different from the comparative example 2 in tissue state and color score, but the example 1 is higher than the comparative example 2 in flavor and taste, which shows that the chemical puffing agent has a certain influence on the flavor and taste of the sweet potato food product, and the sweet potato food product prepared by the biological puffing agent has good flavor and taste, the example 1 is slightly different from the comparative example 3 in color score, but the other 3 indexes are higher than the comparative example 3 and the comparative example 4 in score, which shows that enzymes in the sweet potato and chicken cooperate to better promote the value-added and metabolism of high-sugar dry yeast, improve the fermentation efficiency, and further improve the overall flavor and taste of the egg yolk, which can not only improve the overall flavor and taste of the egg yolk, but also can improve the overall flavor and taste of the egg yolk, but also show that the whole flavor of the egg yolk can be greatly improved by the egg yolk is not added with the acid added in the example 1.

TABLE 3 sensory evaluation results Table

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It should be noted that the above embodiments are merely for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solution described in the above embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or substitutions do not deviate from the essence of the corresponding technical solution from the scope of the technical solution of the embodiments of the present invention.

Claims (7)

1. A method for preparing a sweet potato food product, characterized in that it comprises: S1. Pre-treat sweet potatoes by low-temperature steaming at 50-55℃ for 6-8 minutes to obtain material one, wherein the pre-treated sweet potatoes are in the form of 1cm×1cm×1cm blocks; S2. Add egg yolk and high-sugar-tolerant dry yeast to material one, and ferment at a constant temperature to obtain material two; S3. Add glutinous rice flour to material two and dry it a second time to obtain material three; S4. Vacuum low-temperature frying process is used to obtain the finished product from the material. The addition amount of material one, egg yolk, and high-sugar-tolerant dry yeast is 5:(1-1.2):(0.04-0.06) by mass ratio; The vacuum low-temperature frying temperature is 90-95℃, and the time is 30-35 minutes. 2. The preparation method according to claim 1, characterized in that the high-sugar tolerant dry yeast is activated in warm water at 35°C for 12 min before use. 3. The preparation method according to claim 1, wherein the constant temperature fermentation temperature is 32-35℃ and the fermentation time is 40-45h. 4. The preparation method according to claim 1, wherein the amount of material 2 and glutinous rice flour added is 5:(1-1.5) by mass. 5. The preparation method according to claim 1, characterized in that the secondary drying process results in a material moisture content of 8%. 6. The preparation method according to claim 1, characterized in that, after the frying process, seasoning and packaging are further included. 7. A sweet potato food product prepared according to any one of the preparation methods in claims 1-6.