Avocado ripening process

Abstract

The invention relates to the technical field of fruit ripening acceleration, in particular to an avocado ripening acceleration process which comprises the following steps: placing avocados with the ripening grade of grade 1 in an environment with the temperature of 7-13 DEG C and the relative humidity of 85%-90% for refrigeration; taking out, raising the temperature of the pulp to 18.5-20.5 DEG C at the speed of 1-2 DEG C / h, and keeping the constant temperature for 6 hours; placing in a relatively closed environment, and regulating pulp temperature, ethylene concentration and carbon dioxide concentration according to a target ripening grade; placing the ripened avocados in an environment with the temperature of 18.5-19 DEG C, the carbon dioxide concentration of 1500ppm and the relative humidity of 85%-90% for 7-8 hours; and refrigerating in an environment of 7-10 DEG C. Through multi-parameter quantitative control, staged precise ripening acceleration, pressure difference circulation system and low-temperature gas cooperative regulation and control, precise ripening acceleration, maturity standardization and controllability, large-scale efficient production and quality preservation of avocados are achieved, diversified requirements of fresh food, processing and the like are met, the preservation period is prolonged to 7-12 days, and the grease content reaches 18% or above.

Description

Technical Field

[0001] The invention relates to the technical field of fruit ripening, and in particular to a process for ripening avocados. Background Art

[0002] Avocados, a highly regarded nutritional star among tropical fruits, boast balanced nutritional value. Rich in monounsaturated fatty acids, vitamins E and K, dietary fiber, and various minerals such as potassium and magnesium, they are widely favored by consumers for their cardiovascular health, intestinal health, and energy-boosting properties. In recent years, with the rise of healthy eating trends, avocados have seen continued market demand due to their smooth texture and diverse consumption options, including fresh consumption, spread on bread, salads, and smoothies.

[0003] Because avocados require long-distance transportation to reach markets across China and around the world, farmers typically harvest them when they are 70% to 80% ripe. At this stage, avocados are often dark green, with a hard skin and firm flesh with a bland flavor. They don't taste good eaten directly and must be ripened before they are ready for sale.

[0004] As a typical respiratory burst-type ripening fruit, the traditional ripening method of avocado has significant limitations. The natural ripening method usually places avocados in a room temperature environment or stores them together with fruits such as bananas and apples to ripen. This method usually takes five to fifteen days, and the maturity is difficult to control. Fruits in the same batch are prone to uneven color change, partial softness or unripeness. At the same time, the pulp is prone to water loss due to excessive waiting, seriously affecting product quality. The chemical ripening method uses ethephon solution to wipe or soak the fruit. Although it can accelerate the ripening process, the operation is cumbersome and requires a lot of manpower input, resulting in high labor costs. In addition, the ethephon concentration is difficult to accurately control, which can easily lead to over-ripening of some fruits, resulting in problems such as pulp rot or flavor changes. The ripening cycle is still as long as seven to ten days, which cannot meet the market's demand for rapid turnover.

[0005] With the large-scale development of the avocado industry, traditional ripening processes are no longer able to meet the demands of standardized and mass-produced production. Currently, avocados are mostly transported to distribution centers for centralized ripening and distribution. However, different distributors have varying maturity requirements. For example, the fresh market requires grades 2 to 3, while puree processing requires grade 4. Existing processes lack controllable and scalable methods for varying maturity levels. Therefore, there is an urgent need to establish a precise ripening technology system to meet market demands. Summary of the Invention

[0006] The present invention aims to provide an avocado ripening process. By performing standardized quantitative control on factors such as pulp temperature, ethylene gas concentration, and carbon dioxide concentration during the ripening process, not only can the maturity level of avocados be standardized and controllable, but avocados can also be ripened on a large scale. The maturity level of avocados in the same batch is uniform, the ripening quality is high, and the loss is small.

[0007] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0008] An avocado ripening process specifically comprises the following steps:

[0009] Step S1: refrigeration pretreatment, refrigerating avocados with a maturity level of 1 at a temperature of 7° C. to 13° C. and a relative humidity of 85% to 90%;

[0010] Avocados are a type of fruit that undergoes respiratory climacteric. Low temperatures can slow their metabolic process but cannot completely inhibit ethylene release. If the temperature is above 13°C, the ethylene-induced ripening reaction will continue slowly, potentially causing premature softening of the flesh, localized rot, or a loss of flavor. If the temperature is below 7°C, chilling damage can easily occur, resulting in brown spots on the skin and a firm, unpleasant flesh. Within this range, low temperatures inhibit enzyme activity and ethylene synthesis while also reducing water loss (relative humidity of 85% to 90% effectively maintains skin color and flesh plumpness), thus avoiding overripening or spoilage caused by trace ethylene accumulation.

[0011] Step S2: Heating the avocados to wake them up. After taking the avocados out of the refrigerated environment in step S1, the temperature of the avocado pulp is raised to 18.5°C to 20.5°C at a heating rate of 1°C to 2°C per hour, and the temperature is maintained at this constant temperature for 6 hours.

[0012] When the avocado flesh temperature is below 18°C, ethylene synthase activity is weak, slowing the rate of oil conversion and flavor formation. Above 25°C, anaerobic respiration accelerates, causing off-flavors and increasing the risk of mold growth. Maintaining a constant temperature promotes endogenous ethylene release in avocados, laying the foundation for subsequent ripening.

[0013] Step S3: Ripening by grade: Place the avocados processed in step S2 in a relatively closed environment and adjust the environmental parameters according to the target maturity grade:

[0014] Step S4: To stabilize the maturity, the avocados ripened in step S3 are placed in an environment with a temperature of 18.5° C. to 19° C., a carbon dioxide concentration of 1500 ppm, and a relative humidity of 85% to 95% for 7 to 8 hours;

[0015] Step S5: refrigerate and preserve the avocados after the treatment in step S4. Place the avocados in a refrigerated environment at 7° C. to 10° C.

[0016] Furthermore, in step S3,

[0017] Step S31: ripening the avocados after the heating and constant temperature treatment in step S2 to maturity level 2-3, controlling the environmental parameters as follows: pulp temperature 20.5° C., ethylene gas concentration 500 ppm, carbon dioxide concentration 2000 ppm, relative humidity 85%-90%, for 28 hours;

[0018] The avocado pulp temperature is 18.5°C and maintained for 6 hours, which is connected to the end point of the temperature rise in step S2 to form a continuous constant temperature activation. The pulp temperature is raised to 20.5°C, and ethylene concentration of 500ppm is introduced for 24 hours + 4 hours. During the exhaust stage, the pulp temperature drops to 18.5°C and the accumulated gas is discharged simultaneously.

[0019] Step S32: ripening the avocados ripened to level 2-3 in step S31 to level 3-4 maturity, controlling the environmental parameters as follows: pulp temperature 21° C., ethylene gas concentration 500 ppm, carbon dioxide concentration gradually reduced to 1 ppm, relative humidity 85%-90%, for 28 hours;

[0020] Step S33: Ripening the avocados ripened to level 3-4 in step S32 to level 5 maturity, controlling the environmental parameters as follows: first maintaining the pulp temperature at 20°C for 6 hours, then reducing it to 19.5°C, while controlling the ethylene gas concentration to ≤1ppm, the carbon dioxide concentration to 1800ppm, and the relative humidity to 85%-90% for 35 hours.

[0021] Furthermore, in step S3, the closed environment is a ripening warehouse with a pressure difference control circulation system.

[0022] Furthermore, the maturity level is divided into 1 to 5 levels based on the skin, flesh and smell, and the specific standards are:

[0023] Grade 1: The peel is a bright, even, bluish-green color, firm in texture, and does not deform when pressed with a thumb. There are no purple-black discoloration areas on the surface, and the stem is firm. The flesh is light green, with coarse, tightly structured fibers and a firm texture. The cut surface is smooth with no juice seepage, high adhesion to the peel, weak oiliness, and a distinct green and astringent flavor. There is no avocado aroma, and the oil content is approximately 10%.

[0024] Grade 2: 70% to 80% of the peel is bluish-green, with 15% to 30% turning light purple-black, with a mottled transition. The texture is still hard, with slight resistance when pressed, and the surface is still smooth. The flesh is light green with light yellow, with slightly softened fibers and a slightly hard texture. A small amount of oil occasionally seeps out from the cut surface, and the adhesion to the peel is reduced, with a beginning oily feel. The astringency is reduced, and a light avocado fragrance can be smelled near the base of the fruit. The oil content is approximately 12% to 14%.

[0025] Grade 3: The peel is 40% to 60% green and 40% to 60% purple-black, with the purple-black areas distributed in blocks. The texture is soft, and it deflects 30% to 50% when pressed with a thumb, with a medium rebound rate. The flesh is yellow-green, with further softened fibers and a soft texture. The cut surface is evenly oily, and it deflects slightly when pressed, with a noticeable oiliness. It exudes a refreshing avocado aroma, with the astringency essentially gone and a faint nutty aroma faintly visible. The oil content is approximately 15% to 17%.

[0026] Grade 4: The peel is 70% to 95% dark purple-black, with the remaining green remaining only at the edge of the stem. It is soft, indents 70% to 80% when pressed, rebounds slowly, and has a slightly loose stem with a glossy surface. The flesh is bright yellow-green, with fine, soft fibers and a dense texture. The cut surface is rich and shiny with oil, and oil oozes out with light pressure. There is no hard core. The aroma is rich and mellow, with a distinct nutty and creamy flavor, no astringency, and a harmonious flavor. The oil content is approximately 18% to 20%.

[0027] Level 5: The entire fruit skin is dark purple-black, with dark brown spots in some areas. The texture is extremely soft, and it hardly bounces back when pressed. The fruit stem is easy to fall off. The flesh is dark yellow, the fibers are completely softened, the texture is soft and sticky, the oil is evenly distributed, and the cut surface is easily oxidized and discolored to dark brown. The aroma is strong and slightly sour, and the oil flavor reaches its peak. The oil content is about 21% to 23%.

[0028] The advantages of the present invention compared with the prior art are:

[0029] 1. The present invention incorporates temperature of 7°C to 21°C, humidity of 85% to 90%, ethylene concentration of 1ppm to 500ppm, and carbon dioxide concentration of 0 to 2000ppm into a quantitative control system in each step of avocado ripening: cold pretreatment, gradient temperature activation, graded ripening, maturity stabilization, and cold storage preservation. This overcomes the limitations of traditional natural ripening that relies on room temperature and chemical ripening that uses only ethephon, and achieves multi-factor coordinated and precise control of temperature, humidity, and gas parameters. This is particularly suitable for the physiological characteristics of avocado, which is sensitive to temperature and relies on a precise environment for oil conversion.

[0030] 2. The present invention uses staged parameter control to set corresponding pulp temperature, carbon dioxide concentration, ethylene concentration and duration for different target maturity levels of 2 to 3, 3 to 4, and 5 in the graded ripening step. Combined with the maturity grade standards based on peel color and texture, pulp texture and color, odor and oil content, avocados can be accurately ripened to different grades as needed to meet diverse market demands such as three to four grades of maturity for fresh consumption and five grades of maturity for deep processing. This achieves standardized and controllable maturity and effectively solves problems such as uneven maturity and large quality fluctuations caused by traditional processes.

[0031] 3. The present invention places avocados in the graded ripening steps in a ripening warehouse equipped with a pressure differential circulation system, and cooperates with precise parameter control of each step to achieve a ripening uniformity of more than 95% for the same batch of avocados, shorten the ripening cycle to 3 to 5 days, and reduce the damage rate to below 0.8%, significantly improving industrial production efficiency and economic benefits, and overcoming the shortcomings of traditional natural ripening, which takes 5 to 15 days and has a damage rate of more than 8%.

[0032] 4. The present invention combines low-temperature refrigeration pretreatment with gradient temperature and humidity control. The maturity stabilization step controls the temperature and carbon dioxide concentration, and the graded ripening step accurately controls the gas concentration. This not only ensures uniform oil conversion in the pulp and a rich aroma, with an oil content of more than 18%, but also extends the shelf life to 7 to 12 days, meeting the requirements of cross-regional distribution for fruit quality and storage time, significantly reducing circulation losses, and ensuring the quality of end products. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of this application are used to provide a further understanding of this application and make other features, purposes and advantages of this application more apparent. The drawings and descriptions of the exemplary embodiments of this application are used to explain this application and do not constitute an improper limitation on this application.

[0034] In the attached figure:

[0035] Figure 1 This is a flow chart of an avocado ripening process in Example 1.

[0036] Figure 2 This is a diagram showing the appearance of an avocado with a maturity level of 1 in the embodiment.

[0037] Figure 3 This is a diagram showing the appearance of an avocado with a maturity level of 2 in the embodiment.

[0038] Figure 4 This is a diagram showing the appearance of an avocado with a maturity level of 3 in the embodiment.

[0039] Figure 5 This is a diagram showing the appearance of an avocado with a maturity level of 4 in the embodiment.

[0040] Figure 6 This is a diagram showing the appearance of an avocado with a maturity level of 5 in the embodiment. DETAILED DESCRIPTION

[0041] The detailed descriptions of the following embodiments are used to exemplify the principles of the present application, but are not used to limit the scope of the present application. That is, the avocado ripening process of the present application is not limited to the described embodiments.

[0042] Example 1

[0043] As shown in the following steps S1: the mature level of 1 level of avocado in 7℃-13℃, relative humidity 85%-90% of the environment for cold storage 2-4 days; Figure 1

[0044] In this step, the avocado belongs to the respiratory jump type fruit, low temperature can delay its metabolic process, but can not completely inhibit the release of ethylene. If the cold storage temperature is lower than 7℃, it is easy to cause cold injury, resulting in brown spots on the peel, hard and solid texture of the flesh and peculiar smell; if the temperature is higher than 13℃, the ethylene-induced ripening reaction will still proceed slowly, which may lead to premature softening of the flesh, local soft rot or flavor fading; the cold storage time is controlled in 2-4 days, which can inhibit enzyme activity and ethylene synthesis by low temperature, reduce fruit water loss, maintain the color and luster of the peel and the fullness of the flesh, and avoid over-ripening or deterioration caused by trace ethylene accumulation.

[0045] Step S2: After taking the avocado out of the cold storage environment, the temperature of the avocado is raised at a speed of 1℃-2℃ / hour from 7℃-13℃ to 20.5℃, and then kept constant for 6 hours;

[0046] 2℃ / hour to 20.5℃, and then kept constant for 6 hours;

[0047] In this step, the temperature rising speed needs to be strictly controlled at 1℃-2℃ / hour, and slow temperature rising can avoid physiological stress of the fruit caused by sudden temperature change (such as local soft rot); if the temperature after rising is higher than 25℃, it will lead to sudden increase of the respiration intensity of the flesh, accelerate anaerobic respiration and produce peculiar smell, and the risk of mold proliferation increases; if the temperature is lower than 18℃, the ethylene synthase activity in the flesh is weak, the rate of oil conversion and flavor substance formation slows down, and the quality is affected; constant temperature for 6 hours can promote the endogenous ethylene release of the avocado, laying a foundation for subsequent ripening.

[0048] Step S3: ripening the avocado to maturity level 2-3, placing the avocado treated by temperature rising and constant temperature in step S2 in a relatively closed environment, keeping the temperature of the avocado flesh at 18.5℃ for 6 hours (connected with the temperature rising end point in S2 to form continuous constant temperature activation), then raising the temperature to 20.5℃, and controlling the carbon dioxide concentration in the environment at 2000ppm, the ethylene gas concentration at 500ppm, and the humidity at 85%-90%, for 28 hours.

[0049] ​In a relatively closed environment, the air inside the library body is not naturally exchanged with the air outside the library, and the gas exchange rate needs to be controlled by a differential pressure circulation system to ensure uniform distribution of temperature, humidity and gas concentration, and to avoid local accumulation of ethylene leading to uneven ripening. The system can make the avocado uniformly contact with ethylene, and the temperature distribution is more uniform, realizing synchronous ripening of the flesh from inside to outside and ensuring the consistency of ripening. In specific applications, avocados can be randomly and uniformly extracted, and temperature sensor probes are inserted into the flesh after drilling holes at the shoulder of the fruit. The process detects the temperature of the flesh in real time. During this process, the respiration intensity of the avocado continues to rise, and the absorption efficiency of the flesh to ethylene increases. The ethylene in the air can induce the synthesis and activity of cell wall hydrolases (such as cellulase and pectinase) in the flesh, which will decompose the cellulose and pectin components in the cell wall, making the flesh soft. At the same time, the oil precursor in the flesh of the avocado is accelerated to convert into unsaturated fatty acids under the action of ethylene, and the oil content increases, and flavor substances gradually accumulate. At this time, the fruit is close to the respiration peak.

[0050] Step S4: The flesh temperature of the ripened avocado is controlled at 18.5℃, and the carbon dioxide concentration in the environment is controlled at 1500ppm, and the humidity is controlled at 85%-90%, and the holding time is 8 hours;

[0051] In this step, the temperature of 18.5℃ can make the cell metabolic rate of the avocado decrease by more than 50%, and the carbon dioxide concentration of 1500ppm can competitively inhibit the binding of ethylene and receptor, and the synergistic effect of the two can stabilize the maturity of the fruit and avoid subsequent over-softening; The humidity of 85%-90% can prevent the avocado peel from losing water and shrinking, and can prevent the appearance of brown spots, maintain the smoothness of the fruit surface and the fullness of the flesh, and avoid the texture dry and hard or the flavor of the fruit during the ripening process. taste is little.

[0052] Step S5: The avocado treated in step S4 is stored at 7-10℃;

[0053] This temperature range can further delay the ripening process of the avocado, extend the shelf life to 7-12 days, meet the time efficiency demand of cross-regional short-distance distribution, reduce the circulation loss, and at the same time keep the avocado in the ripening state of 2-3 levels-the peel is 30%-50% from green to purple black, the flesh is slightly soft, the oil sensation is initially apparent, the sour taste is weakened, and the faint fruit aroma begins to release, ensuring that it still meets the quality requirements of short-distance fresh sales when it reaches the terminal market.

[0054] Example 2

[0055] As shown in Figure 1 Step S1: The avocado with a ripening level of 1 is stored at 7-13℃ and a relative humidity of 85%-90% for 2-4 days;

[0056] In this step, avocados are a type of fruit that undergoes respiratory climacteric. Low temperatures can slow their metabolic process but cannot completely inhibit ethylene release. Temperatures below 7°C can easily cause chilling damage, resulting in brown spots on the skin and a hard, unpleasant flesh. Temperatures above 13°C slow the ethylene-induced ripening reaction, potentially causing premature softening, partial rot, or a loss of flavor. 2-4 days of cold storage inhibits enzyme activity and ethylene synthesis through low temperatures, while maintaining a relative humidity of 85% to 90% reduces water loss, maintains skin color and flesh plumpness, and avoids overripening or spoilage caused by trace ethylene accumulation.

[0057] Step S2: After taking the avocado out of the refrigerated environment, the temperature of the avocado flesh is raised from 7°C to 13°C at a rate of 1°C to 2°C per hour to 20.5°C, and the temperature is maintained at this constant temperature for 6 hours;

[0058] In this step, a slow temperature increase of 1-2°C / hour prevents physiological stress (such as localized softness and rot) caused by sudden temperature changes. Temperatures above 25°C can cause a sudden increase in the respiration rate of the flesh, accelerating anaerobic respiration and producing off-flavors, while also increasing the risk of mold proliferation. Temperatures below 18°C ​​weaken the activity of ethylene synthase in the flesh, slowing oil conversion and flavor formation, and affecting quality. Maintaining the temperature for 6 hours promotes the release of endogenous ethylene in the avocado, laying the foundation for subsequent ripening.

[0059] Step S3: ripening the avocado to a maturity level of 3-4;

[0060] Step S31: The avocados that have been heated and maintained at a constant temperature in step S2 are placed in a relatively closed environment. The avocado flesh temperature is first maintained at 18.5°C for 6 hours, and then the temperature is increased to 20.5°C. The carbon dioxide concentration in the environment is controlled to 2000 ppm, the ethylene gas concentration is controlled to 500 ppm, and the humidity is controlled to 85% to 90% for 28 hours (24 hours + 4 hours).

[0061] In a relatively closed environment, the air inside the warehouse and the air outside the warehouse are not exchanged naturally. The gas exchange rate needs to be controlled by a pressure differential circulation system to ensure that the temperature, humidity and gas concentration are evenly distributed, and to avoid local ethylene accumulation that leads to uneven ripening. This system allows avocados to be evenly exposed to ethylene, with a more even temperature distribution, and to achieve synchronous ripening of the flesh from the inside out. During this process, the respiration intensity of avocados continues to rise, and the efficiency of ethylene absorption by the flesh is improved. Ethylene can induce the synthesis and activity of cell wall hydrolases (such as cellulase, pectinase, etc.) in the flesh, decomposing cell wall components to soften the flesh. At the same time, the conversion of oil precursors into unsaturated fatty acids is accelerated, and flavor substances gradually accumulate. The fruit approaches its respiration peak and is eventually ripened to levels 2 to 3.

[0062] Step S32: Adjust the environmental parameters of the avocados ripened to maturity level 2-3 in step S31, first maintaining the avocado flesh temperature at 19.5°C for 6 hours, then raising the temperature to 21°C, and controlling the ethylene gas concentration in the environment to 500 ppm and the humidity to 85%-90%. Simultaneously, gradually reduce the carbon dioxide concentration to 1 ppm (exhaust stage) and maintain this for 28 hours (24 hours + 4 hours).

[0063] In this step, a pulp temperature of 21°C is one of the optimal ranges for ethylene receptor activity in avocado, which can accelerate the conversion of pulp oil and the formation of a dense texture; an ethylene concentration of 500 ppm continues to promote the decomposition of chlorophyll in the peel and the purple-black color change, while promoting further softening of the pulp; gradually reducing the carbon dioxide concentration to 1 ppm can avoid the inhibition of high concentrations of carbon dioxide on the formation of flavor substances and ensure the normal accumulation of pulp aroma.

[0064] The humidity of 85% to 90% continuously prevents the peel from losing water and shrinking, and maintains the smoothness of the fruit surface.

[0065] Step S4: controlling the temperature of the ripened avocado pulp at 19° C., and controlling the carbon dioxide concentration in the environment to 1500 ppm and the humidity to 85% to 90% for 7 hours;

[0066] Step S5: refrigerating the avocados processed in step S4 at 7° C. to 10° C.;

[0067] Example 3

[0068] like Figure 1 As shown, step S1: refrigerate avocados with a maturity level of 1 at a temperature of 7° C. to 13° C. and a relative humidity of 85% to 90% for 2-4 days;

[0069] Step S2: After taking the avocado out of the refrigerated environment, the temperature of the avocado flesh is raised from 7°C to 13°C at a rate of 1°C to 2°C per hour to 20.5°C, and the temperature is maintained at this constant temperature for 6 hours;

[0070] Step S3: ripening the avocado to maturity level 5;

[0071] Step S31: placing the avocados after the heating and constant temperature treatment in step S2 in a relatively closed environment, controlling the pulp temperature to 20.5° C., the carbon dioxide concentration to 2000 ppm, the ethylene gas concentration to 500 ppm, and the humidity to 85% to 90% for 28 hours (24 hours + 4 hours);

[0072] Step S32: Adjust the environmental parameters of the avocados ripened to maturity level 2-3 in step S31: the pulp temperature is controlled to 21° C., the carbon dioxide concentration is gradually reduced to 1 ppm (exhaust stage), the ethylene gas concentration is maintained at 500 ppm, and the humidity is maintained at 85%-90% for 28 hours (24 hours + 4 hours);

[0073] Step S33: The environmental parameters of the avocados ripened to maturity level 3-4 in step S32 are adjusted again: the temperature is maintained at 17.5°C for 6 hours in the early stage, then the temperature is raised to 20.5°C and ethylene is introduced at 500 ppm for 24 hours + 4 hours, then the temperature is maintained at 20°C for 6 hours, and then the pulp temperature is lowered to 19.5°C. The carbon dioxide concentration is simultaneously adjusted to 1500-2000 ppm, the ethylene concentration is controlled to ≤1 ppm (almost empty), and the humidity is maintained at 85%-90% for 35 hours;

[0074] In this step, 20.5℃~21℃ is the optimal range for avocado ethylene receptor activity, which can accelerate the conversion of pulp oil; when the temperature drops to 19.5℃, the cell metabolic rate decreases by more than 50%, effectively delaying overripeness and rot; high ethylene (500ppm) promotes the decomposition of chlorophyll in the peel and purple-black color change, while low ethylene (≤1ppm) focuses on the stability of pulp oil and the accumulation of mellow flavor; when carbon dioxide is ≥1500ppm, it can competitively inhibit the binding of ethylene to the receptor, delay ripening, and avoid the pulp losing its processing value due to excessive softening; 85%~90% humidity can prevent the avocado peel from losing water and shrinking, and the appearance of brown spots, maintaining a smooth fruit surface and plump flesh, and finally ripening to level 5.

[0075] Step S4: The temperature of the ripened avocado pulp is controlled at 18.5° C., the carbon dioxide concentration in the environment is maintained at 1500 ppm, and the humidity is maintained at 85% to 90% for 8 hours;

[0076] In this step, a temperature of 18.5°C can reduce the metabolic rate of avocado cells by more than 50%, and a carbon dioxide concentration of 1500 ppm can competitively inhibit the binding of ethylene to receptors. The synergistic effect of the two can stabilize the maturity of the fruit and avoid excessive softening; a humidity of 85% to 90% can prevent the avocado skin from losing water and shrinking, and the appearance of brown spots, maintaining a smooth fruit surface and plump flesh, and avoiding dry texture or bland flavor caused by water loss during the ripening process.

[0077] Step S5: refrigerating the avocados processed in step S4 at 7° C. to 10° C.;

[0078] This temperature range ensures the soft, glutinous texture and high fat content required for further processing within 7 to 10 days, meeting the timeliness requirements of cross-regional distribution and reducing circulation losses. After refrigeration, avocados maintain Grade 5 maturity quality—the skin is a deep purple-black with some brown spots, the flesh is soft and glutinous, the fat content reaches its peak (approximately 21% to 23%), and the flavor is rich and mellow. The high soluble solids content makes them suitable for further processed products such as avocado puree and sauces.

[0079] Example 4

[0080] like Figure 1 As shown, 2 tons of avocados transported from Mexico to the Shanghai ripening warehouse base were ripened.

[0081] This batch of avocados, shipped from Mexico, was transported via cold chain throughout the entire process. Upon arrival at the Shanghai ripening warehouse, they were at maturity level 1 and then temporarily transferred to a cold storage or freezer, where the ambient temperature is controlled at 7°C to 13°C and the relative humidity is 85% to 90% to stabilize the fruit's condition. A graded ripening plan was developed based on the differentiated needs of downstream customers: 300 kg were ripened to levels 2-3, suitable for short-distance fresh sales, such as immediate stocking in local supermarkets, to meet consumer demand for lightly ripened fruit; 700 kg were ripened to levels 3-4, primarily for the fresh food market, ensuring the fruit's rich oil content and aroma, suitable for home consumption and salads in restaurants; the remaining 1,000 kg were ripened to level 5 and supplied to deep-processing companies for use in products such as avocado puree, sauces, and baking ingredients, fully leveraging their high oil content and soft, glutinous texture.

[0082] Step S1: First, 2 tons of avocados are transferred to the first ripening warehouse and stacked in sections of 300 kg, 700 kg, and 1 ton according to the planned ripening maturity level. The ripening warehouse is heated in the presence of natural air circulation to raise the temperature of the avocado flesh from 7°C to 13°C to 20.5°C, and then maintained at this constant temperature for 6 hours.

[0083] Avocado is a late-ripening fruit with respiratory climacteric. Its respiration is inhibited in a cold storage environment of 7℃ to 13℃. In this step, the temperature is raised and maintained at a constant temperature. During the heating process and the constant temperature maintenance, the respiration intensity of the avocado gradually increases, and the carbon dioxide concentration in the storage gradually increases. This stage is the fruit awakening process, which can activate the endogenous ethylene synthesis mechanism of the fruit and lay the foundation for oil conversion.

[0084] Step S2: The ripening warehouse is sealed, and the avocados that have been heated and kept at a constant temperature are placed in a relatively closed environment. The temperature of the avocado flesh is controlled at 20.5° C., and the carbon dioxide concentration, ethylene concentration, and humidity in the environment are controlled at 2000 ppm, 500 ppm, and 85% to 90% respectively. After maintaining these conditions for 28 hours (i.e., 24 hours plus 4 hours), the avocados are ripe at a level of 2 to 3.

[0085] During this process, the respiration intensity of avocados continues to rise, and the efficiency of the pulp's absorption of ethylene increases. The ethylene in the air can induce the synthesis and activity of cell wall hydrolases in the pulp, such as cellulase and pectinase. These enzymes will decompose the cellulose and pectin components in the cell walls, making the pulp softer. At the same time, the oil precursors in the avocado pulp are accelerated to convert into unsaturated fatty acids under the action of ethylene, the oil content increases, and flavor substances gradually accumulate. At this time, the fruit is close to the peak of respiration.

[0086] In this embodiment, the ripening warehouse utilizes the applicant's previously filed Chinese patent application number CN222465911U, "An Energy-Saving Fruit Pressure-Differential Ripening Warehouse." The disclosed pressure-differential controlled circulation system ensures uniform ethylene exposure to avocados, resulting in more even temperature distribution and synchronized ripening from the inside out, ensuring consistent ripening. In practice, avocados can be randomly and evenly sampled, and a temperature sensor probe inserted into the flesh after a hole is drilled in the shoulder to monitor the flesh temperature in real time.

[0087] Step S3: After 300 kg of avocados ripened to maturity level 2-3 are transported to the second ripening warehouse, the avocado flesh temperature is controlled at 18.5°C, and the carbon dioxide concentration in the environment is controlled at 1500 ppm and the humidity is controlled at 85%-90% for 8 hours; and then refrigerated at 7°C-10°C.

[0088] In the first ripening warehouse where the remaining avocados are stored, the following parameters are adjusted: the pulp temperature is controlled at 21°C, the ethylene gas concentration is maintained at 500ppm, the carbon dioxide concentration is gradually reduced to 1ppm (i.e., the exhaust stage), and the humidity is maintained at 85%-90%. After 28 hours (i.e., 24 hours plus 4 hours), the avocados in the first ripening warehouse are now at maturity level 3-4.

[0089] In the process of ripening avocados with maturity levels of 2 to 3 to 3 to 4, the chlorophyll in the avocado peel gradually decomposes, the purple-black area expands, and the glossiness of the fruit surface increases; the physiological metabolic activity of the pulp continues to increase, mitochondrial respiration accelerates, continuously consuming oxygen and producing carbon dioxide, and at the same time the oil conversion rate accelerates, the nutty aroma and creamy flavor become richer, and the green taste completely disappears.

[0090] In this embodiment, during the process of transporting 300 kg of avocados to the second ripening warehouse, random samples were taken to confirm the maturity and yield rate. The number of samples sampled was 8, of which 7 samples had a maturity level of 2 to 3, with 30% to 50% of the peel turning purple-black. The remaining 1 was not included in the maturity statistics because the fruit stem loosened during transportation.

[0091] Step S4: After the 700 kg of avocados in the first ripening warehouse are transferred to the third ripening warehouse, the avocado pulp temperature is controlled at 19°C, the carbon dioxide concentration in the environment is controlled at 1500 ppm, and the humidity is controlled at 85% to 90% for 7 hours; and then refrigerated at 7°C to 10°C.

[0092] In the first ripening warehouse where the remaining avocados are located, the parameters are adjusted: the pulp temperature is first maintained at 20°C for 6 hours, then dropped to 19.5°C, the ethylene gas concentration is controlled at ≤1ppm, that is, almost emptied, the carbon dioxide concentration is adjusted to 1500-2000ppm, and the humidity is maintained at 85%-90%. After 35 hours, the avocados in the first ripening warehouse are now at a maturity level of 5. Subsequently, the pulp temperature is controlled at 18.5°C, the carbon dioxide concentration in the environment is maintained at 1500ppm, and the humidity is maintained at 85%-90% for 8 hours; then they are refrigerated at 7°C-10°C.

[0093] In the process of ripening avocados with maturity levels of 3 to 4 to level 5, ethylene is almost exhausted, and the fruit's respiration mainly relies on its own metabolism. The peel completely turns dark purple-black, with some brown spots; the pulp fiber further softens, the texture becomes paste-like, and the oil content continues to rise to a peak, meeting the requirements of deep processing for high oil and soft and glutinous texture.

[0094] In this embodiment, during the process of transporting 700 kg of avocados to the third ripening warehouse, 25 samples were randomly inspected, of which 23 reached maturity levels 3 to 4, with 70% to 90% of the peel turning purple-black, and the remaining 2 were at levels 2 to 3, which could be met by extending the ripening time by 1 to 2 hours; 35 samples of avocados expected to be ripened to level 5 were randomly inspected, of which 29 reached maturity levels 5, with the whole fruit being dark purple-black, 2 were over-ripe, with the flesh partially soft and rotten, 3 were at levels 3 to 4, and 1 was at levels 2 to 3, which overall met the quality requirements of deep-processing raw materials.

[0095] The cargo damage rate of this embodiment is 0.8%, which is significantly lower than the 8% or more of the traditional ripening process, reflecting the advantage of precise control.

[0096] It should be noted that the combination of the technical features in the case is not limited to the combination of the claims in the case or the combination of the embodiments in the case. All the technical features disclosed in the case can be freely combined or combined in any way, unless contradictory.

[0097] It should also be noted that the above-mentioned embodiments are only specific embodiments of the present application. Obviously, the present application is not limited to the above-mentioned embodiments, and similar changes or modifications made in accordance with the disclosure of the present application are directly derived or easily conceived by those skilled in the art, and should all fall within the scope of protection of the present application.

Claims

1. A process for ripening avocado, characterized in that: The specific steps include: Step S1: refrigeration pretreatment, refrigerating avocados with a maturity level of 1 at a temperature of 7° C. to 13° C. and a relative humidity of 85% to 90%; Step S2: Heating the avocados to wake them up. After taking the avocados out of the refrigerated environment in step S1, the temperature of the avocado pulp is raised to 18.5°C to 20.5°C at a heating rate of 1°C to 2°C per hour, and the temperature is maintained at this constant temperature for 6 hours. Step S3: Ripening by grade: Place the avocados processed in step S2 in a relatively closed environment and adjust the environmental parameters according to the target maturity grade: Step S4: To stabilize the maturity, the avocados ripened in step S3 are placed in an environment with a temperature of 18.5° C. to 19° C., a carbon dioxide concentration of 1500 ppm, and a relative humidity of 85% to 95% for 7 to 8 hours; Step S5: refrigerate and preserve the avocados after the treatment in step S4. Place the avocados in a refrigerated environment at 7° C. to 10° C.

2. The avocado ripening process according to claim 1, wherein: In step S3, Step S31: ripening the avocados after the heating and constant temperature treatment in step S2 to maturity level 2-3, controlling the environmental parameters as follows: pulp temperature 20.5° C., ethylene gas concentration 500 ppm, carbon dioxide concentration 2000 ppm, relative humidity 85%-90%, for 28 hours; Step S32: ripening the avocados ripened to level 2-3 in step S31 to level 3-4 maturity, controlling the environmental parameters as follows: pulp temperature 21° C., ethylene gas concentration 500 ppm, carbon dioxide concentration gradually reduced to 1 ppm, relative humidity 85%-90%, for 28 hours; Step S33: Ripening the avocados ripened to level 3-4 in step S32 to level 5 maturity, controlling the environmental parameters as follows: first maintaining the pulp temperature at 20°C for 6 hours, then reducing it to 19.5°C, while controlling the ethylene gas concentration to ≤1ppm, the carbon dioxide concentration to 1800ppm, and the relative humidity to 85%-90% for 35 hours.

3. The avocado ripening process according to claim 2, wherein: In step S3, the closed environment is a ripening warehouse with a pressure difference control circulation system.

4. The avocado ripening process according to claim 3, characterized in that: The maturity level is divided into 1 to 5 levels based on the skin, flesh and smell. The specific standards are: Grade 1: The peel is a bright, even, bluish-green color, firm in texture, and does not deform when pressed with a thumb. There are no purple-black discoloration areas on the surface, and the stem is firm. The flesh is light green, with coarse, tightly structured fibers and a firm texture. The cut surface is smooth with no juice seepage, high adhesion to the peel, weak oiliness, and a distinct green and astringent flavor. There is no avocado aroma, and the oil content is approximately 10%. Grade 2: 70% to 80% of the peel is bluish-green, with 15% to 30% turning light purple-black, with a mottled transition. The texture is still hard, with slight resistance when pressed, and the surface is still smooth. The flesh is light green with light yellow, with slightly softened fibers and a slightly hard texture. A small amount of oil occasionally seeps out from the cut surface, and the adhesion to the peel is reduced, with a beginning oily feel. The astringency is reduced, and a light avocado fragrance can be smelled near the base of the fruit. The oil content is approximately 12% to 14%. Grade 3: The peel is 40% to 60% green and 40% to 60% purple-black, with the purple-black areas distributed in blocks. The texture is soft, and it deflects 30% to 50% when pressed with a thumb, with a medium rebound rate. The flesh is yellow-green, with further softened fibers and a soft texture. The cut surface is evenly oily, and it deflects slightly when pressed, with a noticeable oiliness. It exudes a refreshing avocado aroma, with the astringency essentially gone and a faint nutty aroma faintly visible. The oil content is approximately 15% to 17%. Grade 4: The peel is 70% to 95% dark purple-black, with the remaining green remaining only at the edge of the stem. It is soft, indents 70% to 80% when pressed, rebounds slowly, and has a slightly loose stem with a glossy surface. The flesh is bright yellow-green, with fine, soft fibers and a dense texture. The cut surface is rich and shiny with oil, and oil oozes out with light pressure. There is no hard core. The aroma is rich and mellow, with a distinct nutty and creamy flavor, no astringency, and a harmonious flavor. The oil content is approximately 18% to 20%. Level 5: The entire fruit skin is dark purple-black, with dark brown spots in some areas. The texture is extremely soft, and it hardly bounces back when pressed. The fruit stem is easy to fall off. The flesh is dark yellow, the fibers are completely softened, the texture is soft and sticky, the oil is evenly distributed, and the cut surface is easily oxidized and discolored to dark brown. The aroma is strong and slightly sour, and the oil flavor reaches its peak. The oil content is about 21% to 23%.

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