阅读说明：本技术 一种青梅蜜饯的加工方法 (Processing method of preserved green plums ) 是由 项方献 崔书成 彭丽 杨立启 张建锋 于 2020-06-19 设计创作，主要内容包括：本发明提供了一种青梅蜜饯的加工方法,所述加工方法包括：(1)选择成熟度在7-8成、大小均匀的青梅鲜果,清水洗净后备用；(2)将酪蛋白酸钠溶解于水中,再加入抑菌剂,充分搅拌,使混合液中酪蛋白酸钠和抑菌剂的质量百分比浓度分别为0.5-1％和0.01-0.02％,然后对混合液进行剪切、超声处理得到乳液；(3)将步骤(2)得到的乳液与步骤(1)处理后的青梅鲜果混合,进行高压脉冲电场处理；处理完毕后继续浸渍10-20min；(4)将浸渍后的青梅果胚捞出置于糖渍液中充分浸渍；(5)将浸渍后的青梅果胚捞出,沥去多余浸渍液,干燥至果胚表面不黏手,即制得青梅蜜饯。本发明解决青梅蜜饯原果涩味重以及蜜饯保藏性能差的难题。(The invention provides a processing method of green plum preserved fruit, which comprises the following steps: (1) selecting fresh green plum fruits with the maturity of 7-8 and uniform size, and cleaning with clear water for later use; (2) dissolving sodium caseinate in water, adding a bacteriostatic agent, fully stirring to ensure that the mass percent concentrations of the sodium caseinate and the bacteriostatic agent in the mixed solution are 0.5-1% and 0.01-0.02%, and then shearing and ultrasonically treating the mixed solution to obtain emulsion; (3) mixing the emulsion obtained in the step (2) with the fresh green plum fruits treated in the step (1), and carrying out high-voltage pulse electric field treatment; continuing to dip for 10-20min after the treatment is finished; (4) fishing out the dipped green plum fruit embryo and putting the green plum fruit embryo into the sugar solution for full dipping; (5) and fishing out the dipped green plum fruit embryo, draining off redundant dipping liquid, and drying until the surface of the fruit embryo is not sticky, thereby obtaining the green plum preserved fruit. The invention solves the problems of heavy original astringent taste of green plum preserved fruits and poor preservation performance of the preserved fruits.)

1. A processing method of green plum preserved fruit comprises the following steps:

(1) selecting fresh green plum fruits with the maturity of 7-8 and uniform size, removing the soft and shriveled inferior fruits with obvious mechanical damage and diseases, and cleaning with clear water for later use;

(2) dissolving sodium caseinate in water, adding a bacteriostatic agent, fully stirring to ensure that the mass percent concentrations of the sodium caseinate and the bacteriostatic agent in the mixed solution are 0.5-1% and 0.01-0.02%, and then shearing and ultrasonically treating the mixed solution to obtain emulsion;

(3) mixing the emulsion obtained in the step (2) with the fresh green plum fruits treated in the step (1), and performing high-voltage pulse electric field treatment at the treatment temperature of 25-35 ℃, the electric field strength of 20-40kV/cm, the pulse width of 2-4 mu s, the pulse frequency of 200-400Hz and the treatment time of 200-400 pulse numbers; continuing to dip for 10-20min after the treatment is finished;

(4) fishing out the green plum fruit embryo treated in the step (3), and fully soaking in a sugar solution;

(5) and (4) fishing out the green plum fruit embryo obtained after the impregnation in the step (4), draining off redundant impregnation liquid, and drying until the surface of the green plum fruit embryo is not sticky, thus obtaining the green plum preserved fruit.

2. The method for processing green plum preserves of claim 1, characterized in that: the sugar solution is prepared by the following method: adding fructose, xylitol, ammonium glycyrrhizinate, glycine, erythritol and sucralose into water, and uniformly mixing to obtain a sugar stain solution, wherein the concentration of each substance is as follows: 20 to 30 percent of fructose, 20 to 30 percent of xylitol, 0.6 to 0.8 per mill of ammonium glycyrrhetate, 0.08 to 0.1 per mill of glycine, 0.06 to 0.08 per mill of erythritol and 0.01 to 0.02 per mill of sucralose.

3. The method for processing green plum preserves of claim 2, wherein: in the step (4), the green plum fruit blank is soaked in the sugar soaking liquid for 20-40 min.

4. The method for processing green plum preserves according to any of claims 1 to 3, characterized in that: the bacteriostatic agent is lauric acid monoglyceride or sodium benzoate.

5. The method for processing green plum preserves according to any of claims 1 to 3, characterized in that: the shearing and ultrasonic conditions in the step (2) are as follows: shearing the mixed solution for 1-2min at a shearing rate of (10-20) multiplied by 1000rpm, and then carrying out ultrasonic treatment for 10-15min at intervals of 1-2s at a power of 100-150 w.

6. The method for processing green plum preserves according to any of claims 1 to 3, characterized in that: in the step (3), the feeding mass ratio of the fresh green plum fruits to the emulsion is 1: 2 to 5.

7. The method for processing green plum preserves according to any of claims 1 to 3, characterized in that: in the step (5), the drying conditions are as follows: drying with hot air at 40-50 deg.C.

(I) technical field

The invention belongs to the field of food processing, and particularly relates to a processing method of preserved green plums.

(II) technical background

The preserved green plums are products processed by pickling the green plums with sugar or honey, are sour, sweet, tasty and crisp, can promote the production of body fluid to quench thirst, stimulate appetite and relieve depression, stimulate the appetite, and have unique taste and flavor which are deeply loved by consumers.

With the rapid development of the economy of China and the improvement of the living standard of people, the health care consciousness of people is continuously enhanced, and the social demand of the green plum preserves is gradually developing towards diversification as the current popular leisure food. The pickling in the main process flow of the preserved fruit product is a crucial step, in order to promote the pickling effect, sucrose is usually used for repeated sugar boiling or soaking, which is the main reason for long production period and low efficiency of the preserved fruit product, and long-time sugar boiling or soaking can lead the color of the surface of the green plum to become brown, so that the green plum is soft and rotten and has cooked taste, the nutritional value is reduced, the tissue structure is seriously damaged, the sensory evaluation is also reduced, and the problems of microorganism breeding and foreign matter doping are easily caused in the long-time sugar permeating process; the traditional sucrose solution for pickling the preserves is not beneficial to the diffusion of sugar liquid in green plum tissues due to the large molecular weight of sucrose, and is not suitable for special people such as hypertension, diabetes and the like. Therefore, the low-sugar green plum preserved fruit is more suitable for the demands of the masses. The low-sugar preserved fruits have heavy original fruit taste, but for preserved fruit products, the selected raw materials are generally 7 ripe, so that the soluble tannin in the fruits is not completely converted, the low-sugar preserved fruits cannot cover the bitter taste with sweet taste like common high-sugar products, the green plum products have strong astringent feeling and influence the wide application of the products, and the existing deastringency methods comprise warm water deastringency, fresh fruit deastringency, puncture deastringency, plant leaf deastringency, alcohol deastringency and ethylene deastringency, and the deastringency methods are time-consuming and labor-consuming in operation and are not suitable for long-time storage and are not easy to deeply process. Besides the problem of astringency, poor preservability is another disadvantage of low-sugar preserves, and the traditional bacteriostasis method is to directly add a bacteriostat, so that the bacteriostat is short in bacteriostasis time and cannot eliminate the harm of microorganisms for a long time.

Therefore, the development of the green plum preserved fruit product with low sugar, no astringency and good preservation performance can completely meet the preference of consumers for sweet foods, and has wide development prospect.

Patent CN104431254A discloses a method for producing green plum preserves, which uses white sugar to cover green plums to prepare the green plum preserves, but the method selects the white sugar as a sweetener during sugaring, the permeation is slow, the time is consumed, the sugar content of the prepared green plum preserves is too large, and the prepared green plum preserves do not accord with the current low sugar, nutrition and healthy diet trends; patent CN1376407A discloses a method for removing astringent taste of astringent persimmon at high temperature, which is to heat astringent persimmon at high temperature under the condition of no water addition by firepower, microwave, etc. to remove astringent taste, but the method can achieve the aim of removing astringent taste, but has high energy consumption and great damage to fruit and vegetable tissues.

Disclosure of the invention

The invention aims to solve the technical problem of providing a processing method of green plum preserved fruits, and solving the problems of heavy original fruit astringent taste and poor preservation performance of the green plum preserved fruits.

The technical scheme of the invention is specifically explained as follows:

the invention provides a processing method of green plum preserved fruit, which comprises the following steps:

(1) selecting fresh green plum fruits with the maturity of 7-8 and uniform size, removing the soft and shriveled inferior fruits with obvious mechanical damage and diseases, and cleaning with clear water for later use;

(2) dissolving sodium caseinate in water, adding a bacteriostatic agent, fully stirring to ensure that the mass percent concentrations of the sodium caseinate and the bacteriostatic agent in the mixed solution are 0.5-1% and 0.01-0.02%, and then shearing and ultrasonically treating the mixed solution to obtain emulsion;

(3) mixing the emulsion obtained in the step (2) with the fresh green plum fruits treated in the step (1), and performing high-voltage pulse electric field treatment at the treatment temperature of 25-35 ℃, the electric field strength of 20-40kV/cm, the pulse width of 2-4 mu s, the pulse frequency of 200-400Hz and the treatment time of 200-400 pulse numbers; continuing to dip for 10-20min after the treatment is finished;

(4) fishing out the green plum fruit embryo treated in the step (3), and fully soaking in a sugar solution;

(5) and (4) fishing out the green plum fruit embryo obtained after the impregnation in the step (4), draining off redundant impregnation liquid, and drying until the surface of the green plum fruit embryo is not sticky, thus obtaining the green plum preserved fruit.

The green plum preserved fruits prepared by the method are vacuum-packaged by transparent plastic bags to obtain products with different specifications.

Generally, when fresh green plum fruits as a raw material for a confectionery are 7 to 8 ripe (mostly 7 ripe), soluble tannin in the fruits is not completely converted, and strong astringency and astringency are generated.

The bacteriostatic agent can be commonly used bacteriostatic agents in preserved fruits and preserved fruit products, such as lauric acid monoglyceride, sodium benzoate and the like.

Preferably, the shearing and ultrasound conditions in step (2) are: shearing the mixed solution for 1-2min at a shearing rate (10-20) multiplied by 1000rpm, and then carrying out ultrasonic treatment for 10-15min at intervals of 1-2s and with a power of 100-.

Preferably, in the step (3), the feeding mass ratio of the fresh green plum fruits to the emulsion is 1: 2-5, most preferably 1: 2.

in step (4) of the present invention, a sugar solution prepared from a sweetener having a high sweetness intensity is preferably used in order to reduce the amount of sugar used without deteriorating the quality of the product. In a preferred embodiment of the present invention, the sugar solution is prepared by the following method: adding fructose, xylitol, ammonium glycyrrhizinate, glycine, erythritol and sucralose into water, and uniformly mixing to obtain a sugar stain solution, wherein the concentration of each substance is as follows: 20 to 30 percent of fructose, 20 to 30 percent of xylitol, 0.6 to 0.8 per mill of ammonium glycyrrhetate, 0.08 to 0.1 per mill of glycine, 0.06 to 0.08 per mill of erythritol and 0.01 to 0.02 per mill of sucralose. Preferably, in the step (4), the green plum fruit body is soaked in the sugaring liquid for 20-40 min.

Preferably, in the step (5), the drying conditions are as follows: drying with hot air at 40-50 deg.C.

The advantages and the produced process effects of the invention are as follows:

(1) the invention takes the bacteriostatic agent as a disperse phase and the sodium caseinate as a continuous phase to prepare the stable oil-in-water emulsion, the green plums are treated by adopting a high-voltage pulse electric field, the combination of the two can remove the astringent taste of the green plums to the maximum extent, simultaneously has certain protection effect on the bacteriostatic agent, has certain shielding effect on the bad smell possibly generated by the bacteriostatic agent, and can slowly release the bacteriostatic agent to achieve the aim of long-acting bacteriostasis.

Specifically, the green plum fruits picked as the raw materials of the preserved fruits are mostly 7 ripe, soluble tannin in the fruits is not completely converted, strong astringency and astringency can be generated, the original fruit taste of the low-sugar preserved fruits is heavy, and the feeling is more obvious compared with the high-sugar preserved fruits; in addition, bacteria, mold and yeast in the preserves can be increased continuously with the time, but the growth is slow. Therefore, effective suppression of green plum astringency and slow release of bacteriostatic agents are necessary for confectionery products. Adopting high-voltage pulse electric field treatment to open cellulose hydrogen bonds in the primary layer and the secondary layer of the green plum cell wall, weakening non-covalent bonds between cell wall polysaccharide and cellulose fibers, loosening the green plum cell wall, promoting the dissolution of soluble phenols, interacting with amino groups of sodium caseinate, and forming a conjugate through hydrogen bond connection, so that the astringent taste caused by the phenols is reduced, and the viscosity of the material is improved; and the bacteriostatic agent can be embedded and protected to prevent the bacteriostatic agent from being oxidized and deteriorated, so that the aim of slow release is fulfilled.

The preserved fruit can reach low sugar, and simultaneously, the problems of heavy original astringent taste of the green plum preserved fruit and poor preservation performance in the production of the low-sugar preserved fruit are solved.

(2) According to the invention, fructose, xylitol, ammonium glycyrrhizinate, glycine, erythritol and sucralose are selected and mixed in proportion to serve as the sugaring liquid, so that the use amount of sugar is greatly reduced under the condition of not reducing the product quality, and the prepared preserved green plums are fresh and sweet in taste.

Specifically, the sugar in the traditional green plum sugar infiltration process is replaced by mixed sugar, and the high-efficiency sweetener is combined with the nutritive sweetener. The fructose and the xylitol are used as nutritional sweeteners, the metabolism does not depend on insulin, the blood sugar value cannot be increased, fat accumulation is not easy to generate to cause obesity and hyperlipidemia, and the prepared green plum preserved fruit can be widely applied to the diet of diabetics and patients with hepatic insufficiency and is more beneficial to the health of human bodies compared with the traditional high-sugar preserved fruit; after the ammonium glycyrrhizinate, the glycine, the sucralose and the erythritol are compounded, the sweetness can reach 600-fold of that of the sucrose by 700 times, and the compound sweetening agent is used as a high-efficiency sweetening agent to ensure that the sweetness of the whole sugar stain liquid is high, so that the use amount of sugar in the green plum sugar stain liquid can be greatly reduced, and the new trend of the current sugar-free and low-sugar foods can be met. In the compound sweetening agent prepared according to the proportion, the sucralose increases the sweet taste feeling speed of the ammonium glycyrrhizinate, reduces the aftertaste of the ammonium glycyrrhizinate after liquorice, and has a desalting effect on the sour taste of the green plums; erythritol has a synergistic effect on the sweet taste of ammonium glycyrrhizinate, so that the overall sweetness is improved; glycine improves the temperature and cool feeling of ammonium glycyrrhizinate, and a high-efficiency sweetener with pure sweetness is formed after compounding. However, the high-efficiency sweetener has high sweetness and low dosage, cannot form high osmotic pressure, and has poor sugar permeability. The fructose makes up the defect of osmotic pressure well and can penetrate cell tissues quickly. And xylitol is added, so that the green plum preserved fruit can feel cool mint-like taste without foreign flavor when being eaten, and the prepared green plum preserved fruit is sour, sweet and delicious in taste, thick in original fruit flavor and prominent in cool feeling.

(IV) description of the drawings

FIG. 1 is a flow chart of a conventional production process of preserved green plums.

FIG. 2 is a flow chart of the production process of preserved green plums.

Figure 3 is a graph of the release rate of sodium benzoate in different brines.

(V) detailed description of the preferred embodiment

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto: