阅读说明：本技术 一种延长荸荠货架期的处理方法 (Processing method for prolonging shelf life of water chestnuts ) 是由 闵婷 胡铭文 王宏勋 易阳 侯温甫 王丽梅 艾有伟 于 2021-08-20 设计创作，主要内容包括：本发明公开了一种延长荸荠货架期的处理方法,包括如下步骤：步骤1：将新鲜荸荠预冷；步骤2：将步骤1预冷后的新鲜荸荠清洗、去皮,得到去皮荸荠；步骤3：将步骤2去皮荸荠进行减菌处理；步骤4：将步骤3减菌处理后的去皮荸荠切片、切丝或切碎后的得到鲜切荸荠碎料；步骤5：将步骤4制得的鲜切荸荠碎料用保鲜膜封好,并冷藏。本发明发现通过切片、切丝和切碎的方式均可抑制去皮荸荠黄化,延长荸荠货架期,但切碎的方式对抑制去皮荸荠的黄化效果最佳,同时其对荸荠的货架期的延长时间最长。(The invention discloses a processing method for prolonging the shelf life of water chestnuts, which comprises the following steps: step 1: pre-cooling fresh water chestnuts; step 2: cleaning and peeling the fresh water chestnuts precooled in the step 1 to obtain peeled water chestnuts; and step 3: carrying out bacteria reduction treatment on the peeled water chestnuts in the step 2; and 4, step 4: slicing, shredding or chopping the peeled water chestnuts subjected to the bacteria reduction treatment in the step 3 to obtain fresh-cut water chestnut particles; and 5: and (4) sealing the fresh-cut chufa crushed aggregates obtained in the step (4) by using a preservative film, and refrigerating. The invention finds that the peeling chufa can be inhibited from yellowing in the modes of slicing, shredding and chopping, and the shelf life of the chufa is prolonged, but the chopping mode has the best effect on inhibiting the peeling chufa from yellowing, and the prolonging time of the peeling chufa on the shelf life is longest.)

1. A processing method for prolonging the shelf life of water chestnuts is characterized by comprising the following steps:

step 1: pre-cooling fresh water chestnuts;

step 2: cleaning and peeling the fresh water chestnuts precooled in the step 1 to obtain peeled water chestnuts;

and step 3: carrying out bacteria reduction treatment on the peeled water chestnuts in the step 2;

and 4, step 4: slicing, shredding or chopping the peeled water chestnuts subjected to the bacteria reduction treatment in the step 3 to obtain fresh-cut water chestnut particles;

and 5: and (4) sealing the fresh-cut chufa crushed aggregates obtained in the step (4) by using a preservative film, and refrigerating.

2. The method for prolonging the shelf life of water chestnuts according to claim 1, wherein the water chestnut pre-cooling in the step 1 is performed for 12 to 16 hours at a temperature of between 0 and 4 ℃.

3. The method for prolonging the shelf life of water chestnuts according to claim 2, wherein the water chestnut precooling in the step 1 is carried out for 12 hours at 4 ℃.

4. The processing method for prolonging the shelf life of water chestnuts according to claim 1, wherein the sterilization treatment in the step 3 is to place fresh-cut water chestnuts in clear water, introduce ozone into the clear water for 4-6min, take out and dry the water chestnuts, or place the fresh-cut water chestnuts in 0.005-0.015 w/v% NaClO solution, soak the water chestnuts for 8-12min, take out and dry the water chestnuts.

5. The processing method for prolonging the shelf life of water chestnuts according to claim 4, wherein the sterilization treatment in the step 3 is to place the fresh-cut water chestnuts in clear water, introduce ozone into the clear water for 4-6min, take out and dry the water chestnuts, or place the fresh-cut water chestnuts in 0.01 w/v% NaClO solution for 10min, take out and dry the water chestnuts.

6. The method for prolonging the shelf life of water chestnuts according to claim 1, wherein the peeled water chestnuts in the step 4 are sliced to have a thickness of 0.5-1mm, the cut sections of the peeled water chestnuts when cut into shreds are 0.8-1mm x 0.8-1mm, and the side lengths of the peeled water chestnuts when cut into shreds are 0.8-1mm x 0.8-1 mm.

Technical Field

The invention belongs to the field of tissue storage, and particularly relates to a processing method for prolonging the shelf life of water chestnuts.

Background

At present, the method for prolonging the shelf life of the peeled tissue is generally realized by adding various additives to the peeled tissue, but the additives are not beneficial to maintaining the nutritional ingredients of the tissue, and consumers generally keep a careful attitude to the additives.

Disclosure of Invention

In order to solve the technical problems, the invention provides a processing method for prolonging the shelf life of water chestnuts by only slicing, shredding or chopping the peeled water chestnuts without additives.

The technical scheme of the invention is as follows: a processing method for prolonging the shelf life of water chestnuts comprises the following steps:

step 1: pre-cooling fresh water chestnuts;

step 2: cleaning and peeling the fresh water chestnuts precooled in the step 1 to obtain peeled water chestnuts;

and step 3: carrying out bacteria reduction treatment on the peeled water chestnuts in the step 2;

and 4, step 4: slicing, shredding or chopping the peeled water chestnuts subjected to the bacteria reduction treatment in the step 3 to obtain fresh-cut water chestnut particles;

and 5: and (4) sealing the fresh-cut chufa crushed aggregates obtained in the step (4) by using a preservative film, and refrigerating.

Preferably, the water chestnut precooling in the step 1 is carried out for 12-16h at the temperature of 0-4 ℃.

Specifically, the water chestnut precooling in the step 1 is carried out for 12 hours at the temperature of 4 ℃.

Preferably, the sterilization treatment in the step 3 is to place the fresh-cut water chestnuts in clear water, introduce ozone into the clear water for 4-6min, take out and dry the water chestnuts, or place the fresh-cut water chestnuts in 0.005-0.015 w/v% NaClO solution, take out and dry the water chestnuts after soaking for 8-12 min.

Specifically, the sterilization treatment in the step 3 is to place the fresh-cut water chestnuts in clear water, introduce ozone into the clear water for 4-6min, take out and dry the water chestnuts, or place the fresh-cut water chestnuts in 0.01 w/v% NaClO solution for 10min, take out and dry the water chestnuts.

Specifically, the thickness of the peeled water chestnuts in the step 4 is 0.5-1mm when the peeled water chestnuts are sliced, the section of the peeled water chestnuts in the step 4 is 0.8-1mm multiplied by 0.8-1mm, and the side length of the peeled water chestnuts in the step 4 when the peeled water chestnuts are sliced is 0.8-1mm multiplied by 0.8-1 mm.

The invention has the beneficial effects that: the invention finds that the peeling chufa can be inhibited from yellowing in the modes of slicing, shredding and chopping, and the shelf life of the chufa is prolonged, but the chopping mode has the best effect on inhibiting the peeling chufa from yellowing, and the prolonging time of the peeling chufa on the shelf life is longest.

Drawings

FIG. 1 is a diagram illustrating the effect of different cutting types on the appearance quality of fresh-cut water chestnuts during storage according to an embodiment of the present invention;

FIG. 2 is a graph showing the effect of different cutting types on color difference and weight loss rate of fresh-cut water chestnuts during storage according to the embodiment of the invention;

FIG. 3 is a graph showing the effect of different cutting types on headspace gas composition during storage of fresh-cut water chestnuts according to an embodiment of the present invention;

FIG. 4 is a graph showing the effect of different cutting types on the metabolism of phenolic substances in fresh-cut water chestnuts according to an embodiment of the present invention;

FIG. 5 is a graph showing the effect of different cutting types on the active oxygen content of fresh-cut water chestnuts according to an embodiment of the present invention;

FIG. 6 is a graph showing the effect of different cleavage types on POD, SOD and CAT activities of fresh-cut water chestnut according to the present invention;

FIG. 7 is a graph showing the effect of different cutting types on ascorbic acid content and DPPH radical scavenging rate of fresh-cut water chestnut according to an embodiment of the present invention.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

Example 1

The embodiment provides a processing method for prolonging the shelf life of water chestnuts, which is characterized by comprising the following steps:

step 1: precooling fresh water chestnuts for 12 hours at the temperature of 4 ℃;

step 2: cleaning and peeling the fresh water chestnuts precooled in the step 1 to obtain peeled water chestnuts;

and step 3: carrying out bacteria reduction treatment on the peeled water chestnuts in the step 2, wherein the bacteria reduction treatment is to place fresh-cut water chestnuts in clear water, introduce ozone into the clear water for 5min, take out and dry the water chestnuts, or place the fresh-cut water chestnuts in 0.01 w/v% NaClO solution for 10min, take out and dry the water chestnuts;

and 4, step 4: dividing the peeled water chestnuts subjected to the bacteria reduction treatment in the step 3 into four groups, wherein one group is a control group for peeling and trimming fruits, and the remaining three groups are respectively a slice group, a shredding group or a chopping group (namely a dicing group), wherein the thickness of the slice group during slicing is 0.5-1mm, the shredding specification of the shredding group is 0.8-1mm multiplied by 0.8-1mm, and the side length of the chopping group is 0.8-1mm multiplied by 0.8-1 mm;

and 5: sealing the water chestnuts treated by the four subgroups with preservative films, and refrigerating.

As shown in figure 1, the fresh-cut water chestnuts after being cut into pieces have slight yellowing phenomenon during the whole storage period, while the fresh-cut water chestnuts after being peeled have obvious yellowing phenomenon during 60h storage, and meanwhile, the fresh-cut water chestnuts after being cut into pieces and shredded have yellowing phenomenon during the whole storage period, but are weaker than the peeled whole fruits, and the fact that the fresh-cut water chestnuts are cut into pieces can be found from figure 1 to effectively inhibit the yellowing.

L^*The value represents the brightness of the sample surface, L^*The lower the value, the darker the surface, a^*The value represents the red-green value of the sample surface, a^*Higher values indicate a redder surface color of the sample; a is^*The lower the value, the greener the surface of the surface sample, b^*Values represent the yellow-blue value of the sample surface, b^*Higher values indicate that the sample indicates a more yellow color; b^*Lower values indicate that the sample showed a more blue color. As shown in FIG. 2, L of fresh-cut water chestnut^*The value gradually decreases during storage, while a^*Value b and^*increasing value, peeling whole fruit and slicing L^*The value decreased sharply at 24h, indicating that peeling and slicing of fresh cut water chestnuts would accelerate browning, while the minced fresh cut water chestnuts, during the entire storage period, L^*The value is slightly reduced, as can be seen from FIG. 2See, a of the cut group^*Value b and^*the value remained unchanged after 60h of storage, while the other groups showed an upward trend and remained at a higher value in the later period of storage, consistent with the yellowing phenomenon in the later period of storage, which indicates that the cutting treatment can effectively inhibit the yellowing of fresh-cut water chestnuts.

After fresh-cut treatment, the integrity of tissue cells of the water chestnuts is damaged, so that fruit and vegetable juice flows outwards and is exposed in the air, nutrient substances are lost, and the weight of the water chestnuts is continuously reduced in the storage process. As can be seen from fig. 2, the weight loss rate of fresh-cut water chestnuts showed a tendency to increase throughout storage, and the weight loss rate of the minced group was significantly higher than that of the remaining group (P <0.05) throughout storage.

As can be seen from FIG. 3, the oxygen concentration of fresh-cut water chestnuts showed a downward trend throughout the storage period, and the cutting < shredding < slicing < peeling and fruit setting; the concentration of carbon dioxide is in an ascending trend, and the fruit is cut into pieces, sliced and peeled. After storage for 36h, there were significant differences in oxygen and carbon dioxide concentrations between the different cleavage types (P < 0.05). This indicates that peeling and cutting the water chestnuts can significantly improve the inhibition effect. After 60 hours, the oxygen concentration of peeled whole fruits, sliced, shredded and cut fruits is reduced by 26.54 percent, 34.47 percent, 69.90 percent and 92.88 percent respectively. It is evident that the shredding process significantly increases the ratio of carbon dioxide and oxygen in the package, creating a low oxygen environment that inhibits browning, consistent with the above color studies.

As shown in figure 4, the total phenolic content, the total flavone content, the PAL activity and the PPO activity of fresh-cut water chestnut are determined, so as to explore the influence of different cutting types on the metabolism of phenolic substances of fresh-cut water chestnut, the phenolic compound is a substrate for browning of fruits and vegetables, as can be seen from figure 4, the total phenolic content of fresh-cut water chestnut in the whole storage period shows an ascending trend, wherein the total phenolic content of the water chestnut subjected to cutting treatment is less than that of other groups, and the total phenolic content of peeled whole fruits and sliced water chestnut has no significant difference (P) in 48h of storage (P is the total phenolic content of peeled whole fruits and sliced water chestnut)>0.05) and after 24h storage, the total phenol content was significantly higher than that of the shredding and chopping process (P)<0.05), fresh-cutting the water chestnutsThe yellowing phenomenon of the rear surface occurs, and researches show that the main reason is that the fresh-cut water chestnut surface tissues generate flavonoid substances, as can be seen from figure 4, the total flavone content of peeled whole fruit, sliced and shredded groups shows an increasing trend in the whole storage period, the total flavone content of shredded groups is almost unchanged, and the total flavone content of each group is remarkably different after 24 hours of storage (P)<0.05), this with b)^*The values change similarly.

PAL plays an important role in regulating and controlling the synthesis of phenolic substances in plants, and research shows that the PAL activity change trend is similar to the change trend of total phenol content, as can be seen from FIG. 4, the PAL activity of fresh-cut water chestnut generally shows an increasing trend in the process of storage for 60h at 20 ℃, the PAL activity of the slicing treatment group is higher than that of the other treatment groups at the later stage of storage, while the PAL activity of the chopping treatment group is always lower than that of the other groups, which is similar to the change of total phenol content, PPO plays an important role in enzymatic browning, in the presence of oxygen, PPO can catalyze phenolic substances to be quinone substances, which can further polymerize to further deepen the color, as can be seen from FIG. 4, the PPO activity of the chopping group has no obvious change during the whole storage period, the PPO activity of the chopping group is always higher than that of the other groups and shows an increasing trend, while peeled whole fruit and shredded fruit show an increasing trend, but the differences were not significant (P <0.05), and the PPO activity in the sliced group was consistently significantly higher than in the minced group (P <0.05) throughout storage.

OH of freshly cut chufa was determined as shown in FIG. 5^-，·O₂ ^-Production rate, H₂O₂The content of MDA, so as to explore the influence of different cutting types on the active oxygen content of fresh-cut water chestnut, OH^-Is one of the most oxidizing free radicals in ROS, can react with almost all cell components, and has great harm to organisms. As can be seen from FIG. 5, OH is present during the entire storage period^-The production rate rises first and then falls, and a peeled whole fruit appears>Slicing>Shredding>The size relationship of the cut pieces. OH of the cut-up treatment group^-The production rate after 36h of storage was always significantly less than the rest of the group (P)<0.05). From FIG. 5O₂ ^-The rate of production tended to decrease and then increase throughout the storage period, and the treatment group was chopped up to O after 12 hours of storage₂ ^-The production rate is significantly less than the rest of the group (P)<0.05). Of slice treatment group O₂ ^-The production rate reached a maximum at 36h, which was 3.2 times that of the shredding group. H₂O₂When plants are stressed, they accelerate the senescence and disintegration of cells. As can be seen in FIG. 5, the whole fruit was peeled, sliced and cut into pieces H in the treatment group during the whole storage period₂O₂The content showed an increasing trend, while the H of the treatment group was chopped₂O₂The content hardly changed, and H of the slice treatment group₂O₂The content was always significantly higher than that of the cut treatment group (P)<0.05). The results show that the active oxygen content of the fresh-cut water chestnuts can be obviously inhibited by the chopping treatment, the MDA content is an index for measuring the stress degree of plants, and the damage degree of a membrane system can be indirectly judged. As can be seen from FIG. 5, the MDA content was on an increasing trend throughout storage, with the MDA content in the shredded group being significantly higher than in the remaining group (P)<0.05), the MDA content of the peeled whole fruit is always at the lowest, which is consistent with the damage degree of the fresh-cut water chestnut.

SOD is the key enzyme in plants to prevent oxidative stress, and can be harmful to organism-O₂ ^-Is diverged into H₂O₂CAT, POD will be H₂O₂Decomposition into H harmless to tissue₂And O. As shown in FIG. 6, throughout the storage period, the POD activity of the peeled whole fruit, sliced and shredded group showed an upward trend, while the POD activity of the shredded group was hardly changed and was always significantly lower than that of the remaining group (P)<0.05). SOD activity was gradually increased with the increase of storage time, wherein the sliced group was higher than the rest group at 24h storage and the cut group was significantly lower than the rest group after 36h storage (P)<0.05). FIG. 6 shows that CAT activity increased first and then decreased, reaching a maximum at 24 h. Although CAT activity in the cut-up group was always lower than that in the other groups, the cut-up treatment did not significantly differ from that in the peeled whole fruit and cut-up treatment during the whole storage period (P)<0.05), significantly lower than the slice-treated group at 24h, 48h. In conclusion, the cutting treatment can inhibit the activity of POD, SOD and CAT in fresh-cut water chestnut.

Ascorbic acid is an essential nutrient for human body and also an important reducing agent. As can be seen from FIG. 7, the anti-staltic acid content of the cut and peeled set of whole fruits generally increased during the whole storage period, the anti-staltic acid content of the cut and shredded set decreased before 24h and increased after 24h up to the end of storage, but the content decreased slightly overall. The ascorbic acid content of the sliced group was always higher than that of the remaining groups and significantly higher than that of the shredded group (P <0.05), while the ascorbic acid content of the shredded group was always at a minimum. DPPH free radical clearance is one of the indexes for evaluating antioxidant capacity. As can be seen from FIG. 7, the DPPH radical clearance of fresh-cut water chestnuts showed an upward trend, wherein the DPPH radical clearance of the slicing treatment group was always higher than that of the chopping treatment group, and the difference was significant at 12h, 36h and 60h (P < 0.05). The results show that the Vc content and DPPH free radical clearance rate of the fresh-cut water chestnuts can be reduced by the chopping treatment.

The research results show that different cutting treatments have different influences on the quality of fresh-cut water chestnuts, wherein the cutting and chopping treatments are important to pay attention. After the water chestnuts are peeled and cut, the L can be effectively slowed down^*Reduction of value, b^*The increase of the value keeps the inherent color of the water chestnuts. The fresh-cut treatment of the water chestnuts can obviously improve the respiration effect of the water chestnuts. Compared with the slicing treatment, the chopping treatment can reduce the synthesis and accumulation of phenols and flavonoids of the fresh-cut water chestnuts and inhibit the increase of PPO activity by inhibiting PAL activity, thereby delaying the browning and yellowing of the fresh-cut water chestnuts during storage. Compared with the chopping treatment group, the slicing treatment group can obviously improve OH^-，·O₂ ^-Production rate, increase of H₂O₂The content of the water chestnut cell membrane lipid can accelerate the peroxidation degree of the water chestnut cell membrane lipid, thereby causing the quality deterioration. Compared with the group treated by cutting, the slicing treatment can remarkably improve the increase of total phenol and total flavone content, improve the ascorbic acid content and DPPH free radical clearance rate of fresh-cut water chestnut, and also induce and improve POD, SOD and CAT active oxygen scavenging enzymes in the water chestnutThe activity of the water chestnut powder enhances the oxidation resistance of the fresh-cut water chestnut.

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable to various fields of endeavor for which the invention may be embodied with additional modifications as would be readily apparent to those skilled in the art, and the invention is therefore not limited to the details given herein and to the embodiments shown and described without departing from the generic concept as defined by the claims and their equivalents.