阅读说明：本技术 一种水果生物保鲜的方法 (Biological fresh-keeping method for fruits ) 是由 高岳 司文会 余雁 李小平 于 2017-07-05 设计创作，主要内容包括：本发明公开了一种水果生物保鲜的方法；柠檬香茅、意大利蜡菊均有较好的抗菌活性,结合甜罗勒除了在水果表面抗氧化以及抑菌外,更主要是满足水果保鲜的特异性要求,能有效锁水,而蜂蜜除了有一定的抗菌作用外,还能结合提取液的成份比如醇、酯使保鲜剂更容易在枇杷表面成膜。本发明制备方法简单,纯天然,安全无毒,应用于枇杷有良好的杀菌保鲜作用,避免了传统物理和化学杀菌对水果营养和品质的影响。(The invention discloses a method for biologically preserving fruits; the lemon citronella and the Italian helichrysum have good antibacterial activity, the sweet basil is combined to resist oxidation and inhibit bacteria on the surface of the fruit, the specific requirement of fruit preservation is mainly met, water can be effectively locked, and the honey has a certain antibacterial effect, and the preservative can be combined with the components of the extracting solution such as alcohol and ester to enable the preservative to form a film on the surface of the loquat more easily. The preparation method is simple, pure natural, safe and nontoxic, has good sterilization and fresh-keeping effects when being applied to the loquat, and avoids the influence of traditional physical and chemical sterilization on the nutrition and quality of the fruits.)

1. A method for biologically preserving fruits is characterized by comprising the following steps:

(1) respectively removing impurities from lemon citronella, Italian helichrysum and sweet basil, cleaning, and air-drying in the dark at room temperature; then mixing the dried lemongrass, the Italian helichrysum and the sweet basil, and crushing to obtain crushed substances;

(2) mixing the crushed material with distilled water according to a mass ratio of 1: 5-10; then adding sodium chloride, and stirring to obtain a pre-extracting solution; then boiling the pre-extracting solution, filtering, and collecting filtrate as a fresh-keeping extracting solution;

(3) mixing the fresh-keeping extract with honey and sterilized distilled water, and stirring to obtain a biological fresh-keeping agent;

(4) and soaking the fruits in the biological preservative, draining and air-drying to finish the biological preservation of the fruits.

2. The biological fruit preservation method according to claim 1, characterized in that, by mass, the preservation extract is 65-70%, the honey is 15-20%, and the balance is sterilized distilled water.

3. The method for biologically preserving fruit according to claim 1, wherein the mass percent of the lemon citronella is 40-50%, the mass percent of the Italian Helichrysum is 30-40%, and the balance is sweet basil.

4. The method for biologically preserving fruits according to claim 1, wherein the particle size of the crushed material is 50 to 100 mesh; the dosage of the sodium chloride is 2.5 to 3.5 percent of the mass of the crushed material.

5. The method for biologically preserving fruit according to claim 1, wherein the temperature of the pre-extraction liquid obtained by stirring is 45 ℃ for 30 minutes; the boiling time was 45 minutes.

6. Preserved fruit prepared by the method for biologically preserving fruit according to claim 1.

Technical Field

The invention belongs to the technical field of preservatives, and particularly relates to a biological preservative, a preparation method thereof and application thereof in preserving loquat.

Background

The loquat is a rare and special fruit in the south of China, is rich in nutrition and sweet in taste, belongs to seasonal fruits, is easily damaged by machinery and microorganisms, is easy to rot at normal temperature to lose edible value, is difficult to store and transport for a long distance under common conditions, and restricts the development of the loquat. The air-conditioned fresh-keeping and low-temperature storage effects in the existing batch fresh-keeping technology are better, but the required equipment investment is large; the chemical preservative has low cost, but poor effect, and is easy to leave toxic substances, thereby bringing threat to human health. The biological preservative is natural and safe, has low cost and obvious effect, so the application of the natural biological preservative for preservation is a development trend of batch preservation.

Lemon grass, also known as lemon grass or citronella grass, is an aromatic grass, is native to asia, is spread in tropical regions such as india, srilanca, indonesia, africa and the like, and leaves have a strong lemon flavor. Theoretical research shows that the lemon grass has good antioxidant effect and antibacterial activity, and researches show that the main active component citral of the lemon grass has killing and inhibiting effects on candida tropicalis, candida albicans, candida glabrata, candida pseudotropicalis, malassezia, penicillium, aspergillus niger, aspergillus flavus, escherichia coli, staphylococcus aureus, enterococcus, proteus, gonococcus, salmonella enterica, campylobacter jejuni, listeria monocytogenes, helicobacter pylori, bacillus subtilis and the like.

The conventional lemon lemongrass is reported in plant preservation, and a small amount of reports show that the lemon lemongrass is matched with other chemical reagents to form a preservation system or is matched with inert atmosphere for application; and are citronella essential oil. The main reason is that the lemongrass has a certain bacteriostatic effect, but the lemongrass is far from being used for plant preservation, and the essential oil is adopted to exert the effect to the maximum extent. However, the side effects of chemical agents and environmental problems are significant, and essential oils are complicated to prepare and inconvenient to use, and are not suitable especially for fruit handling.

Disclosure of Invention

The invention discloses a biological preservative and a preparation method thereof, wherein lemon citronella is matched with Italian helichrysum and sweet basil for the first time, and an effective component aqueous solution is obtained as a fruit preservative through the limitation of the proportion and preparation parameters, particularly, the loquat is preserved in a targeted manner, so that an obvious preservation effect is achieved.

The invention adopts the following technical scheme:

a preparation method of a biological preservative comprises the following steps:

(1) respectively removing impurities from lemon citronella, Italian helichrysum and sweet basil, cleaning, and air-drying in the dark at room temperature; then mixing the dried lemongrass, the Italian helichrysum and the sweet basil, and crushing to obtain crushed substances;

(2) mixing the crushed material with distilled water according to a mass ratio of 1: 5-10; then adding sodium chloride, and stirring to obtain a pre-extracting solution; then boiling the pre-extracting solution, filtering, and collecting filtrate as a fresh-keeping extracting solution;

(3) mixing the fresh-keeping extract with honey and sterilized distilled water, and stirring to obtain the biological fresh-keeping agent.

The invention also discloses a biological fresh-keeping extracting solution and a preparation method thereof, and the method comprises the following steps:

(1) respectively removing impurities from lemon citronella, Italian helichrysum and sweet basil, cleaning, and air-drying in the dark at room temperature; then mixing the dried lemongrass, the Italian helichrysum and the sweet basil, and crushing to obtain crushed substances;

(2) mixing the crushed material with distilled water according to a mass ratio of 1: 5-10; then adding sodium chloride, and stirring to obtain a pre-extracting solution; then boiling the pre-extracting solution, filtering, and collecting filtrate as fresh-keeping extracting solution.

The invention also discloses a biological fresh-keeping method for fruits, which comprises the following steps:

(1) respectively removing impurities from lemon citronella, Italian helichrysum and sweet basil, cleaning, and air-drying in the dark at room temperature; then mixing the dried lemongrass, the Italian helichrysum and the sweet basil, and crushing to obtain crushed substances;

(2) mixing the crushed material with distilled water according to a mass ratio of 1: 5-10; then adding sodium chloride, and stirring to obtain a pre-extracting solution; then boiling the pre-extracting solution, filtering, and collecting filtrate as a fresh-keeping extracting solution;

(3) mixing the fresh-keeping extract with honey and sterilized distilled water, and stirring to obtain a biological fresh-keeping agent;

(4) and soaking the fruits in the biological preservative, draining and air-drying to finish the biological preservation of the fruits.

The invention further discloses an application of the biological preservative or the biological preservation extracting solution in fruit preservation.

According to the invention, by mass, 40-50% of lemon citronella, 30-40% of Italian helichrysum and the balance sweet basil; helichrysum italicum, native to eastern area of Mediterranean, belongs to one of Compositae, has yellow small cluster-shaped flower and certain bactericidal activity; sweet Basil, the scientific name (Sweet Basil), a native annual herb of Basil genus, lamiaceae, has a strong, pleasant characteristic aroma throughout the plant, and is currently used for eating, medicine and appreciation. The invention combines lemongrass, italian helichrysum and sweet basil, and the water extract has good antioxidant activity and better antibacterial activity, and particularly has obvious water locking effect when being used as a fruit preservative, which is not possessed by common preservatives.

According to the invention, by mass, 65-70% of fresh-keeping extract, 15-20% of honey and the balance of sterilized distilled water; the aqueous solution preservative is one of creativity of the invention, has the advantages of convenient preparation and simple use, avoids the pollution of organic matters to the environment and the side effect on fruits, and mainly solves the problem of threat to human health. Because the extraction of essential oil can play a role of activity better, most of the existing plant extraction antistaling agents are mainly essential oil obtained by organic solvent extraction, and the obtained aqueous solution antistaling agent not only overcomes the problem that the existing pure plant extract cannot be effectively preserved, but also solves the defect that the aqueous solution extract has poor effect through reasonable compatibility of raw materials and limitation of preparation process; the obtained preservative not only delays the water loss and the respiration of the loquats, but also can reduce the putrefaction deterioration caused by putrefactive bacteria on the surfaces of the loquats, and the good fruit rate reaches 93.7 percent after the loquats are preserved for 25 days.

In the invention, the particle size of the crushed material is 50-100 meshes; the using amount of the sodium chloride is 2.5 to 3.5 percent of the mass of the crushed material; stirring to obtain pre-extraction solution at 45 deg.C for 30 min; the boiling time was 45 minutes.

Specifically, the preparation method of the preservative comprises the following steps:

1. selecting 40-50 parts of high-quality lemongrass, 30-40 parts of italian helichrysum and the balance of sweet basil, removing impurities and foreign matters, washing the lemongrass, the italian helichrysum and the balance of sweet basil completely with clear water, drying the lemongrass, the italian helichrysum and the sweet basil at 25 +/-2 ℃ in the dark, crushing the lemongrass, the italian helichrysum and the sweet basil into 50-100 meshes together, mixing the crushed mixture and distilled water according to the mass ratio of 1: 5-10, adding the mixture into a stirrer, adding sodium chloride accounting for 2.5-3.5% of the weight of the crushed mixture, stirring the mixture at 45 ℃ for 30 minutes for pre-extraction, transferring the pre-extraction solution into a pot;

2. adding 65-70 parts of the extract obtained in the step 1 into 15-20 parts of honey, supplementing the rest with sterilized distilled water, fully stirring for 2 minutes to prepare the preservative, and storing the preservative in a refrigerator at 4-5 ℃ for later use.

The fruit preservation method comprises the following steps:

and (3) soaking the fruits in the obtained preservative for 4-5 minutes, draining, and air-drying to finish preservation.

The preservative and the preservation method disclosed by the invention are suitable for fruits, especially loquat, and aiming at the deterioration characteristics in the storage process and the characteristics of high water content, high sugar content and soft quality, the prepared product can limit the respiration of the fruits and keep moisture, so that the preservation time of the fruits is prolonged; has the advantages of corrosion resistance, fresh keeping, sterilization, water loss prevention and prominent fresh keeping effect.

The biological preservative is prepared from natural raw materials, the lemongrass and the senecio italica have good antibacterial activity, sweet basil is combined to resist oxidation and inhibit bacteria on the surface of fruits, the specific requirements of fruit preservation are mainly met, water can be effectively locked, and the honey has a certain antibacterial effect, and the preservative can be more easily formed into a film on the surface of the loquat by combining the components of an extracting solution such as alcohol and ester. The preparation method is simple, pure natural, safe and nontoxic, has good sterilization and fresh-keeping effects when being applied to the loquat, and avoids the influence of traditional physical and chemical sterilization on the nutrition and quality of the fruits.

Detailed Description

Example one

1. Selecting 45 parts of high-quality lemongrass, 35 parts of italian helichrysum and 20 parts of sweet basil, removing impurities and foreign matters, washing the lemongrass, the italian helichrysum and the sweet basil with clear water, drying the lemongrass, the italian helichrysum and the sweet basil at the dark place at room temperature, crushing the lemongrass, the italian helichrysum and the sweet basil into 80 meshes together, mixing the crushed mixture and distilled water according to the mass ratio of 1:8, adding the mixture into a stirrer, adding sodium chloride accounting for 3% of the weight of the crushed mixture, stirring the mixture at 45 ℃ for 30 minutes for pre-extraction, transferring the pre-extraction solution into a pot;

2. and (3) adding 68 parts of the extracting solution obtained in the step (1) into 18 parts of honey and 14 parts of sterilized distilled water for complement, fully stirring for 2 minutes to prepare the preservative, and storing the preservative in a refrigerator at the temperature of 4-5 ℃ for later use.

3. Fresh-keeping effect of biological fresh-keeping agent on loquat

Soaking loquat in the obtained preservative for 4 minutes, draining, air-drying, wrapping with a polyethylene breathable film, and preserving under the conditions that the relative humidity is 90%, the temperature is 4-5 ℃, storing for 25 days, measuring the weight loss rate, the good fruit rate, the hardness and the soluble solid content every 5 days, and comparing without using the preservative.

The test results shown in Table 1 show that after the biological preservative is used for treatment, the water loss and the respiration of the loquats are delayed, the spoilage caused by spoilage bacteria on the surfaces of the loquats can be reduced, and the good fruit rate reaches 93.7 percent after the loquats are preserved for 25 days; the fruit is placed in a natural environment, after the fruit is treated by the biological preservative, the fruit yield is 99.3% after the fruit is placed for 2 days, 94.2% after the fruit is placed for 6 days, 92.3% after the fruit is placed for 8 days, 93.8% after the fruit is placed for 2 days without being treated by the preservative, and 62.4% after the fruit is placed for 3 days.

Example two

1. Selecting 40 parts of high-quality lemongrass, 40 parts of italian helichrysum and 20 parts of sweet basil, removing impurities and foreign matters, washing the lemongrass, the italian helichrysum and the sweet basil with clear water, drying the mixture in the dark at room temperature, crushing the lemongrass, the italian helichrysum and the sweet basil into 50 meshes together, mixing the crushed mixture and distilled water according to the mass ratio of 1:5, adding the mixture into a stirrer, adding sodium chloride accounting for 3.5% of the weight of the crushed mixture, stirring the mixture at 45 ℃ for 30 minutes for pre-extraction, transferring the pre-extraction solution into a pot, boiling the mixture for extraction for 45 minutes, filtering the mixture, and collecting filtrate to;

2. and (3) adding 20 parts of honey and 10 parts of sterilized distilled water into 70 parts of the extracting solution obtained in the step (1) for complement, fully stirring for 2 minutes to prepare the preservative, and storing the preservative in a refrigerator at the temperature of 4-5 ℃ for later use.

3. Fresh-keeping effect of biological fresh-keeping agent on loquat

Soaking fructus Eriobotryae in the obtained antistaling agent for 5 min, draining, air drying, wrapping with polyethylene gas-permeable membrane, preserving at 4-5 deg.C with relative humidity of 85% and for 25 days, and determining weight loss rate of 2.36%, good fruit rate of 92.3%, and hardness of 4.7kg/cm²And the content of soluble solid is 8.1 percent, which shows that after the biological preservative is used for treatment, the water loss and the respiration of the loquats are delayed, and the putrefaction deterioration caused by putrefactive bacteria on the surfaces of the loquats can be reduced.

EXAMPLE III

1. Selecting 50 parts of high-quality lemongrass, 40 parts of italian helichrysum and 10 parts of sweet basil, removing impurities and foreign matters, washing the lemongrass, the italian helichrysum and the sweet basil with clear water, drying the lemongrass, the italian helichrysum and the sweet basil in the dark at room temperature, crushing the lemongrass, the italian helichrysum and the sweet basil into 100 meshes together, mixing the crushed mixture and distilled water according to the mass ratio of 1:10, adding the mixture into a stirrer, adding sodium chloride accounting for 3.5% of the weight of the crushed mixture, stirring the mixture at 45 ℃ for 30 minutes for pre-extraction, transferring the pre-extraction solution into a pot, boiling;

2. adding 15 parts of honey and 15 parts of sterilized distilled water into 70 parts of the extracting solution obtained in the step 1 for complement, fully stirring for 2 minutes to prepare the preservative, and storing the preservative in a refrigerator at the temperature of 4-5 ℃ for later use.

3. Fresh-keeping effect of biological fresh-keeping agent on loquat

Soaking fructus Eriobotryae in the obtained antistaling agent for 5 min, draining, air drying, wrapping with polyethylene gas-permeable membrane, preserving at 4-5 deg.C with relative humidity of 95% for 25 days, and determining weight loss rate of 2.33%, good fruit rate of 92.5%, and hardness of 4.6kg/cm²And the content of soluble solid is 8.1 percent, which shows that after the biological preservative is used for treatment, the water loss and the respiration of the loquats are delayed, and the putrefaction deterioration caused by putrefactive bacteria on the surfaces of the loquats can be reduced.