Pineapple ripening process

Abstract

The invention relates to the technical field of fruit ripening acceleration, in particular to a pineapple ripening acceleration process which comprises the following steps: refrigerating pineapples of which the ripening grade is grade 1 in an environment of which the temperature is 7-10 DEG C and the relative humidity is 85-90%; taking out the pineapples from the refrigeration environment, raising the temperature of the pulp to 25-30 DEG C at the temperature raising speed of 1-2 DEG C / h, and keeping the constant temperature for 5-8 hours; the processed pineapples are placed in a relatively closed environment, and environment parameters are regulated and controlled according to the target maturity grade; placing the ripened pineapple pulp in an environment with the temperature of 10-12 DEG C, the carbon dioxide concentration of 3000ppm and the humidity of 85%-90%, and keeping the constant temperature for 7-8 hours; and refrigerating the treated pineapples at the temperature of 10 DEG C. Through multi-parameter quantitative control, staged ripening acceleration, a pressure difference circulation system and low-temperature gas cooperative regulation and control, multi-factor precise ripening acceleration, controllable maturity, large-scale efficient production and quality preservation of pineapples are achieved, and various requirements are met.

Description

Technical Field

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

[0002] Pineapple, a popular tropical fruit known for its nutritional value, is rich in vitamin C, vitamin B6, bromelain, dietary fiber, and various minerals. It is highly favored by consumers for its benefits, including promoting digestion, boosting immunity, and alleviating fatigue. In recent years, as the concept of healthy eating has become more popular, market demand for pineapple has continued to rise, thanks to its sweet and juicy flavor and diverse ways to enjoy it, including fresh, juicing, making desserts, and cooking dishes.

[0003] Pineapple production is primarily distributed across tropical and subtropical regions around the world. Domestically, Hainan, Xuwen in Guangdong, and Xishuangbanna in Yunnan are the most widely cultivated areas, while overseas, production is primarily concentrated in Thailand, the Philippines, and Brazil. Because pineapples require long-distance transportation to reach domestic and global markets, farmers typically harvest them when they are 70% to 80% ripe. At this stage, the pineapples appear light yellow or yellow-green, with a hard skin, low sweetness, high acidity, and a brittle texture. They are not ideal when eaten directly, and require post-ripening (or accelerated ripening) to reach full maturity before they can be marketed.

[0004] As a fruit that ripens after respiratory climacteric, the traditional ripening method of pineapple has obvious limitations. Natural ripening is to ripen pineapples in a room temperature environment or a basket covered with straw, which usually takes 3 to 10 days. However, the maturity is difficult to control. Fruits in the same batch are prone to inconsistent color change, partial overripeness or underripeness, and the flesh tastes hard and sour, affecting the quality. Chemical ripening usually involves spraying or soaking the fruit with ethephon solution.

[0005] Although it can speed up ripening, the operation is cumbersome and requires a lot of manual processing, which has high labor costs. In addition, the concentration of ethephon is difficult to accurately control, which can easily cause some fruits to ripen too quickly, become soft and rotten, or have a poor flavor. The ripening cycle is as long as 5 to 8 days, which cannot meet the market supply turnover needs.

[0006] With the large-scale development of the pineapple industry, traditional ripening processes can no longer meet the needs of standardized, mass-produced production. Currently, pineapples are mostly transported to distribution centers for centralized ripening and distribution. However, different distributors have different requirements for maturity, such as 2-3 for fresh consumption and 4 for canned fruit. Existing processes lack controllable, scalable methods for adjusting the maturity levels, necessitating the development of a precise ripening technology system. Summary of the Invention

[0007] The invention aims to provide a pineapple ripening process, which standardizes the maturity level of pineapples by performing standardized quantitative control on factors such as pulp temperature, ethylene gas concentration, and carbon dioxide concentration during the ripening process, and performs large-scale ripening on pineapples, thereby achieving the effects of uniform maturity level, high ripening quality, and low waste in the same batch of pineapples.

[0008] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0009] A pineapple ripening process specifically comprises the following steps:

[0010] Step S1: low-temperature refrigeration pretreatment, placing the pineapples with maturity level 1 in an environment with a temperature of 7° C. to 10° C. and a relative humidity of 85% to 90% for refrigeration;

[0011] Pineapples 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 10°C, the ethylene-induced ripening reaction will continue slowly, potentially causing premature softening or a loss of flavor. If the temperature is below 7°C, chilling damage can easily occur, leading to spots on the skin and a change in flavor. Keeping temperatures between 7°C and 10°C can inhibit enzyme activity and ethylene synthesis while reducing water loss. Maintaining a relative humidity of 85% to 90% effectively maintains skin color and flesh plumpness, thus preventing overripening or spoilage caused by trace ethylene accumulation.

[0012] Step S2: Activate the gradient temperature increase, take the pineapple out of the cold storage environment, increase the temperature of the pulp to 25°C to 30°C at a heating rate of 1°C to 2°C per hour, and maintain the constant temperature for 5 to 8 hours;

[0013] When the temperature of pineapple flesh is lower than 20℃, the activity of ethylene synthase is weak and the rate of conversion of sucrose into soluble sugar slows down; when it exceeds 35℃, anaerobic respiration will be accelerated, causing the flesh to produce fermentation odor and increasing the risk of mold growth; the constant temperature stage can promote the release of endogenous ethylene in pineapple, laying the foundation for subsequent ripening.

[0014] Step S3: ripening by grade, placing the pineapples processed in step S2 in a relatively closed environment, and adjusting environmental parameters according to the target maturity grade;

[0015] In the pineapple ripening process, the regulation of key parameters is crucial to the ripening effect and fruit quality: in terms of temperature, 25℃ to 28℃ is the optimal range for the activity of pineapple ethylene receptors, which can accelerate the saccharification of the pulp; when the temperature drops to 20℃, the metabolic rate of pineapple cells decreases by more than 50%, which can effectively delay the over-ripening of the fruit. In terms of gas concentration regulation, high ethylene concentrations of 800-1200ppm can promote the decomposition and color change of chlorophyll in the peel, while low ethylene concentrations of 150-300ppm focus on promoting sugar accumulation in the pulp; and when the carbon dioxide concentration is ≥3000ppm, it can delay the ripening of the fruit by competitively inhibiting the binding of ethylene to the receptor. Humidity control is also critical. Maintaining the humidity at 85% to 95% can prevent the pineapple peel from losing water and shrinking, maintain the plumpness of the pulp, and avoid the problem of dry and hard taste caused by water loss during the ripening process.

[0016] Step S4: placing the pineapple pulp ripened in step S3 in an environment with a temperature of 10° C. to 12° C., a carbon dioxide concentration of 3000 ppm, and a humidity of 85% to 90%, and maintaining the constant temperature for 7 to 8 hours;

[0017] During this stage, low temperature and high carbon dioxide concentration inhibit the respiration of the fruit, thereby delaying the ripening process, stabilizing the maturity, and preventing the fruit from excessive softening.

[0018] Step S5: refrigerate the pineapple processed in step S4 at 10°C.

[0019] The refrigerated environment can continuously inhibit enzyme activity and ethylene release, reduce water loss, and keep the pineapple at its best quality after ripening within 10 to 15 days.

[0020] Furthermore, in step S3,

[0021] Step S31: ripening the pineapple after the heating and constant temperature treatment in step S2 to level 2-3, controlling the environmental parameters as follows: pulp temperature 25°C-28°C, carbon dioxide concentration 1500-3000 ppm, ethylene concentration 800-1200 ppm, relative humidity 85%-95%, for 12-20 hours;

[0022] Step S32: ripening the pineapple ripened to level 2-3 in step S31 to level 3-4, controlling the environmental parameters as follows: pulp temperature 20°C-25°C, carbon dioxide concentration 1 ppm, ethylene concentration 150-300 ppm, relative humidity 85%-95%, for 25-28 hours;

[0023] Step S33: ripening the pineapple ripened to level 3-4 in step S32 to level 5, controlling the environmental parameters as follows: pulp temperature 20°C-25°C, carbon dioxide concentration 1500-2000 ppm, ethylene concentration ≤1 ppm, relative humidity 85%-95%, for 32-42 hours.

[0024] Furthermore, the closed environment is a ripening warehouse with a pressure difference control circulation system.

[0025] Furthermore, the maturity level is based on the skin, flesh and smell. The specific standards are:

[0026] Grade 1: In the early stages of fruit development, the skin is bluish-green and firm, the eye is dark green and deeply sunken, it does not deform when pressed with a thumb, and there are no yellowing areas on the surface; the flesh is white, with coarse and densely arranged fibers, a firm texture, tight connections between cells, no depression when pressed, the flesh adheres tightly to the skin, and there is very little juice; it has a distinct green and astringent flavor, lacks the characteristic sweet aroma of pineapple, and has a sugar content of 10.8%;

[0027] Grade 2: Early maturity: 70% to 80% of the peel is bluish-green, with 15% to 30% of the eye and surrounding area turning orange-yellow. The color transition is uneven, and the texture is still relatively hard. The flesh is light yellow, the fibers are slightly softened, the texture is slightly hard, and it rebounds slightly when pressed. The juice content is slightly increased. The astringent smell is weakened, and a light pineapple fragrance begins to appear. The sugar content is 13.5%.

[0028] Grade 3: Half-ripe, with the rind 40% to 60% each of green and orange, and a mottled appearance. The eye gradually becomes fuller, the texture softens, and a thumb press indents 30% to 50%. The flesh is yellow, the fibers further soften, the texture is soft, and it deforms noticeably when pressed. It is juicy and has a fresh pineapple aroma, with a significantly reduced sour taste and a beginning sweetness. The sugar content is 15.2%.

[0029] Grade 4: Fully ripe, with 70% to 95% of the peel golden yellow, and the remaining green area concentrated near the base. The eye is plump and prominent, soft in texture, and easily dented when pressed. The flesh is dark yellow, with fine and soft fibers, a moderate texture, soft and juicy, and loose connections between cells. Juice oozes out with light pressure. The aroma is rich pineapple, with a balanced ratio of sweet and sour, no astringency, and a pure flavor. The sugar content is 16.5%.

[0030] Level 5: Overripe, the skin of the fruit is uniformly golden yellow, with some areas having a dark orange hue, the eyes are full and shiny, the texture is extremely soft, and it is difficult to rebound after being pressed; the flesh is orange-yellow, the fibers are completely softened, extremely soft and juicy, and obvious juice oozes out when pressed; the aroma is strong and slightly sweet, the sugar content reaches its peak, the soluble solids are ≥14%, and the sugar content is 17.8%.

[0031] The advantages of the present invention compared with the prior art are:

[0032] The present invention incorporates temperature of 10°C to 28°C, humidity of 85% to 95%, ethylene concentration ≤1ppm to 1200ppm, and carbon dioxide concentration of 0 to 3000ppm into a quantitative control system in each step of low-temperature cold storage pretreatment, gradient temperature activation, graded ripening, maturity stabilization, and cold storage preservation of pineapples. For example, low-temperature cold storage pretreatment controls 7°C to 10°C and humidity of 85% to 90%, and graded ripening regulates different gas concentrations and temperatures according to target levels. This breaks through the limitations of traditional natural ripening that relies on room temperature and chemical ripening that only uses ethephon, and achieves precise ripening with the coordination of multiple factors.

[0033] The present invention uses staged parameter regulation to set corresponding pulp temperature, carbon dioxide concentration, ethylene concentration and duration for target maturity levels of 2-3, 3-4 and 5 in the graded ripening steps, respectively. Combined with the maturity level standards based on the smell of the peel and pulp, pineapples can be ripened to different levels as needed to meet diverse needs such as fresh consumption and deep processing, thereby achieving standardized and controllable maturity and solving the problem of uncontrollable maturity in traditional processes.

[0034] The present invention places the pineapples in the graded ripening steps in a ripening warehouse equipped with a pressure difference control circulation system, and coordinates precise parameter control of each step, such as gradient temperature rise activation at 1°C to 2°C per hour and constant temperature for 5 to 8 hours, and graded ripening lasting 12 to 42 hours. This achieves a ripening uniformity of 95% or more for the same batch of pineapples, shortens the ripening cycle to 2 to 4 days, and reduces the cargo damage rate to 0.8%, thereby significantly improving industrial production efficiency and overcoming the shortcomings of traditional processes with long cycles and high cargo damage.

[0035] The present invention combines low-temperature refrigeration with gas regulation. The low-temperature refrigeration pretreatment and refrigerated preservation steps adopt a low-temperature environment, the maturity stabilization step controls the temperature and carbon dioxide concentration, and the graded ripening step regulates the gas concentration. This achieves uniform saccharification of pineapple pulp, rich aroma, and soluble solids ≥14%. At the same time, it extends the shelf life to 10 to 15 days, meeting the requirements of cross-regional distribution on fruit quality and storage time, and ensuring terminal quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] 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.

[0037] In the attached figure:

[0038] Figure 1 The present invention is a flow chart of a pineapple ripening process in Example 1.

[0039] Figure 2This is a diagram showing the appearance of a pineapple with a maturity level of 1 in the embodiment.

[0040] Figure 3 This is a diagram showing the appearance of a pineapple with a maturity level of 2 in the embodiment.

[0041] Figure 4 This is a diagram showing the appearance of a pineapple with a maturity level of 3 in the embodiment.

[0042] Figure 5 This is a diagram showing the appearance of a pineapple with a maturity level of 4 in the embodiment.

[0043] Figure 6 This is a diagram showing the appearance of a pineapple with a maturity level of 5 in the embodiment. DETAILED DESCRIPTION

[0044] The detailed description of the following embodiments is used to exemplify the principles of the present application, but cannot be used to limit the scope of the present application, that is, the pineapple ripening process of the present application is not limited to the described embodiments.

[0045] Example 1

[0046] like Figure 1-4 As shown, step S1: refrigerate pineapples with maturity level 1 at 7°C to 10°C and relative humidity of 85% to 90% for 2 to 4 days. Pineapples are tropical fruits and should not be refrigerated for too long to avoid the risk of chilling injury.

[0047] Step S2: After taking the pineapple out of the refrigerated environment, heating it to raise the temperature of the pineapple pulp from 7°C to 10°C at a heating rate of 1°C to 2°C / hour to 26°C to 28°C, and then maintaining the constant temperature for 6 hours;

[0048] In this step, if the temperature is higher than 35°C, the respiration intensity of the pulp will increase sharply, accelerating anaerobic respiration to produce fermentation odor and increase the risk of mold proliferation; when it is lower than 20°C, the activity of ethylene synthase in the pulp is weak, and the rate of conversion of sucrose into soluble sugar slows down, affecting the formation of flavor.

[0049] Step S3: ripening the pineapple to a maturity level of 2-3, placing the pineapple after the heating and constant temperature treatment in step S2 in a relatively closed environment, controlling the pineapple pulp temperature to 26-28° C., and controlling the carbon dioxide concentration in the environment to 2000 ppm, the ethylene gas concentration to 1000 ppm, and the humidity to 90%-95% for 16 hours.

[0050] In a relatively closed environment, the air inside the warehouse and the air outside the warehouse are not exchanged naturally. The exchange rate needs to be controlled by a pressure difference control circulation system to ensure uniform distribution of temperature, humidity and gas concentration.

[0051] Step S4: The ripened pineapple pulp is kept at a temperature of 10°C to 12°C, with the carbon dioxide concentration in the environment maintained at 3000 ppm and the humidity at 85% to 90% for 8 hours. This stage, through the synergistic effect of low temperature and high carbon dioxide, stabilizes the fruit's maturity and prevents subsequent over-softening.

[0052] Step S5: refrigerate the pineapple processed in step S4 at 10° C. to extend the shelf life to 10 to 15 days.

[0053] Example 2

[0054] like Figure 1-4 As shown, step S1: refrigerate the pineapples with maturity level 1 in an environment of 7° C. to 10° C. and relative humidity of 85% to 90% for 2 to 4 days.

[0055] Step S2: After taking the pineapple out of the refrigerated environment, heating it, raising the temperature of the pineapple pulp from 7° C. to 10° C. at a heating rate of 1° C. to 2° C. per hour to 26° C. to 28° C., and maintaining the constant temperature for 7 hours.

[0056] Step S3: ripening the pineapple to maturity level 3-4,

[0057] Step S31: placing the pineapple after the heating and constant temperature treatment in step S2 in a relatively closed environment, controlling the pineapple pulp temperature to 26° C. to 28° C., and controlling the carbon dioxide concentration in the environment to 2000 ppm, the ethylene gas concentration to 1000 ppm, and the humidity to 90% to 95% for 16 hours;

[0058] Step S32: Adjust the environmental parameters of the pineapple that has been ripened to maturity level 2-3 in step S31, control the pineapple pulp temperature to 20° C.-23° C., and control the carbon dioxide concentration in the environment to gradually decrease to 1 ppm through the exhaust stage, gradually decrease the ethylene gas concentration to 100-200 ppm, and maintain the humidity at 90%-95% for 26 hours.

[0059] Step S4: controlling the temperature of the ripened pineapple pulp to 10° C. to 12° C., and controlling the carbon dioxide concentration in the environment to 3000 ppm and the humidity to 85% to 90% for 7 hours;

[0060] Step S5: refrigerate the pineapple processed in step S4 at 10° C. to extend the shelf life to 10 to 15 days.

[0061] Example 3

[0062] like Figure 1-4 As shown, step S1: refrigerate the pineapple with maturity level 1 at 7° C. to 10° C. and relative humidity of 85% to 90% for 2 to 4 days;

[0063] Step S2: After taking the pineapple out of the refrigerated environment, heating it to raise the temperature of the pineapple pulp from 7°C to 10°C at a heating rate of 1°C to 2°C / hour to 28°C, and then maintaining the constant temperature for 7 hours;

[0064] Step S3: ripening the pineapple to level 5;

[0065] Step S31: placing the pineapple after the heating and constant temperature treatment in step S2 in a relatively closed environment, controlling the pineapple pulp temperature to 26° C. to 28° C., and controlling the carbon dioxide concentration in the environment to 2000 ppm, the ethylene gas concentration to 1000 ppm, and the humidity to 90% to 95% for 16 hours;

[0066] Step S32: adjusting environmental parameters for the pineapples ripened to maturity level 2-3 in step S31, controlling the pineapple pulp temperature to 26° C.-28° C., controlling the carbon dioxide concentration in the environment to gradually decrease to 1 ppm through the exhaust stage, adjusting the ethylene gas concentration to 200 ppm, and maintaining the humidity at 90%-95% for 26 hours;

[0067] Step S33: The pineapples ripened in step S32 to maturity levels 3 to 4 are again adjusted to environmental parameters, controlling the pineapple pulp temperature to 20° C. to 23° C., and controlling the carbon dioxide concentration in the environment to 1800 ppm, the ethylene gas concentration to ≤1 ppm, and the humidity to 90% to 95% for 35 hours;

[0068] Step S4: controlling the temperature of the ripened pineapple pulp to 10° C. to 12° C., and controlling the carbon dioxide concentration in the environment to 3000 ppm and the humidity to 85% to 90% for 8 hours;

[0069] Step S5: refrigerate the pineapple after the treatment in step S4 at 10° C. to ensure that the high sugar content and soft texture required for further processing are maintained within 10 days.

[0070] Cold storage pretreatment must strictly follow the safe temperature range of 7℃ to 10℃. Temperatures below 7℃ can easily cause chilling damage, resulting in spots on the skin and change in the taste of the flesh; temperatures above 10℃ will accelerate the release of endogenous ethylene in the fruit, causing the flesh to soften prematurely, affecting the subsequent ripening rhythm and quality.

[0071] The heating process needs to maintain a slow rate of 1℃-2℃ / hour. This rate can avoid physiological stress on the fruit due to sudden temperature changes and prevent local soft rot. After heating, a constant temperature range of 25℃~30℃ needs to be maintained. This range can maximize the activation of ethylene synthase in the fruit, laying the foundation for the efficient advancement of the subsequent ripening process.

[0072] Differentiated gas control strategies need to be formulated according to different ripening levels: when ripening to level 2-3, a high ethylene concentration of 800-1200 ppm is used to accelerate the color change of the peel, and at the same time, a medium-to-high carbon dioxide concentration of 1500-3000 ppm is used to balance the respiration intensity of the fruit to avoid excessive respiration leading to rapid nutrient consumption; when ripening to level 3-4 fresh eating stage, the ethylene concentration needs to be reduced to 150-300 ppm, focusing on the accumulation of sugar in the pulp, and at the same time gradually reducing the carbon dioxide concentration to near 0 to avoid its inhibition of fruit flavor and ensure a balanced sweet and sour taste when eaten fresh; when ripening to level 5 deep processing stage, the ethylene concentration needs to be emptied to ≤1ppm, and a carbon dioxide concentration of 1500-2000 ppm is used to delay overripening of the fruit, ensure that the sugar in the pulp accumulates stably to the peak, and make the soluble solids content reach the standard of ≥14%, meeting the deep processing requirements for raw material sugar.

[0073] Humidity control must be carried out throughout the entire ripening process, and the humidity range of 85% to 95% must always be maintained. This range can prevent the pineapple peel from losing water and shrinking, especially protecting the integrity of the eye area, avoiding the sunken eye due to water loss and affecting the appearance, and avoid mold contamination caused by excessive humidity (over 95%), thereby ensuring the stable quality of the fruit from ripening to subsequent processing.

[0074] Example 4

[0075] like Figure 1-6 As shown, 2 tons of pineapples transported from Sanya, Hainan to the Shanghai ripening warehouse base were ripened.

[0076] This batch of pineapples departed from Sanya, Hainan, and 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 facility, where the temperature is maintained at 7.5°C and the relative humidity is maintained at 85%-90% to stabilize the fruit. Based on downstream customer demand, 300kg of the pineapples will be ripened to levels 2-3 (suitable for short-distance fresh sales), 700kg to levels 3-4 (primarily for the fresh food market), and the remaining 1,000kg to level 5 (for further processing).

[0077] Step S1: First, 2 tons of pineapples are transported to a first ripening warehouse and stacked in sections of 300 kg, 700 kg, and 1 ton according to the planned maturity level of ripening; the ripening warehouse is heated in a cavity with natural air circulation, and the temperature of the pineapple pulp is raised from 7° C. to 10° C. to 26° C. to 28° C., and then the temperature is maintained at a constant level for 6 hours;

[0078] Pineapple is a late-ripening fruit with respiratory climacteric. Its respiration is inhibited in a cold storage environment of 7℃ to 10℃. In this step, the temperature is raised and maintained at a constant temperature. During the heating process and constant temperature maintenance, the respiration intensity of the pineapple 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.

[0079] Step S2: The ripening warehouse is sealed, and the pineapples after being heated and kept at a constant temperature are placed in a relatively closed environment, the pineapple pulp temperature is controlled to be 26° C. to 28° C., and the carbon dioxide concentration, ethylene gas concentration, and humidity in the environment are controlled to be 2000 ppm, 1000 ppm, and 85% to 95% respectively. After maintaining the temperature for 16 hours, the pineapples are at a maturity level of 2 to 3.

[0080] During this process, the respiration intensity of the pineapple 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 (such as cellulase, pectinase, etc.) in the pulp. These enzymes will decompose the cellulose and pectin components in the cell walls, making the pulp softer. At the same time, polysaccharides such as sucrose in the pineapple pulp are accelerated to decompose into monosaccharides such as glucose and fructose under the action of ethylene, and the soluble sugar content increases. At this time, the fruit is close to the peak of respiration.

[0081] In this embodiment, the ripening warehouse adopts the Chinese patent application number CN222465911U "An Energy-Saving Fruit Pressure Differential Ripening Warehouse", which can make the pineapples evenly exposed to ethylene, more evenly distribute the temperature, and achieve synchronous ripening of the flesh from the inside to the outside, ensuring the consistency of ripening; in specific applications, pineapples can be randomly and evenly selected, and after a hole is opened at the eye of the fruit, a temperature sensor probe can be inserted into the flesh to detect the flesh temperature in real time.

[0082] Step S3: After 300 kg of pineapples ripened to maturity level 2-3 are transported to the second ripening warehouse, the pineapple pulp temperature is controlled at 10° C. to 12° C., and the carbon dioxide concentration and humidity in the environment are controlled at 3000 ppm and 85% to 90% for 8 hours; and then the pineapples are refrigerated at 10° C.

[0083] In the first ripening warehouse where the remaining pineapples were stored, the following parameters were adjusted: the pulp temperature was controlled at 23°C, the ethylene gas concentration was reduced to 100-200 ppm, the carbon dioxide concentration was gradually reduced to 1000 ppm through the exhaust phase, and the humidity was maintained at 85%-95%. After 26 hours, the pineapples in the first ripening warehouse were at maturity level 3-4.

[0084] In the process of ripening pineapples with maturity levels of 2 to 3 to 3 to 4, the chlorophyll in the pineapple peel gradually decomposes, the synthesis of orange-yellow carotenoids increases, and the fruit eye turns from green to plump orange-yellow; 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 rate of conversion of sucrose into soluble sugar accelerates, and the sour and sweet flavors tend to be balanced.

[0085] Step S4: After the 700 kg of pineapples in the first ripening warehouse are transferred to the third ripening warehouse, the pineapple pulp temperature is controlled at 10° C. to 12° C., and the carbon dioxide concentration in the environment is controlled at 3000 ppm and the humidity is controlled at 85% to 90% for 8 hours; and then refrigerated at 10° C.

[0086] In the first ripening warehouse where the remaining pineapples were located, the parameters were adjusted: the pulp temperature was maintained at 22°C, the ethylene gas concentration was controlled at ≤1ppm (almost emptied), the carbon dioxide concentration was adjusted to 1800ppm, and the humidity was maintained at 85%-95%. After 35 hours, the maturity level of the pineapples in the first ripening warehouse was level 5; then the pulp temperature was controlled at 10°C-12°C, the carbon dioxide concentration in the environment was maintained at 3000ppm, and the humidity was 85%-90% for 8 hours; then they were refrigerated at 10°C.

[0087] In the process of ripening pineapples 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 chlorophyll in the peel is completely decomposed, showing a uniform golden yellow; the pulp fiber is further softened, and the soluble solids content continues to rise, eventually reaching a peak of ≥14%, meeting the requirements of deep processing for high sugar content and soft texture.

[0088] In step S3, during the process of transporting 300 kg of pineapples to the second ripening warehouse, 8 samples were randomly sampled to confirm the maturity and yield rate. Among them, the maturity level of 7 samples reached level 2 to 3, and the remaining 1 was not included in the maturity statistics because the peel was slightly damaged during transportation.

[0089] In step S4, during the process of transporting 700 kg of pineapples to the third ripening warehouse, 25 samples were randomly inspected, of which 23 reached maturity levels 3 to 4, 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 pineapples expected to be ripened to level 5 were randomly inspected, of which 29 reached maturity levels 5, 2 were over-mature (partially soft and rotten flesh), 3 were at levels 3 to 4, and 1 was at levels 2 to 3, which met the overall quality requirements of deep-processing raw materials.

[0090] The cargo damage rate of this embodiment is 0.8%, which is significantly lower than the 5% or more of the traditional ripening process, reflecting the advantage of precise control.

[0091] It should be noted that the combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0092] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made therefrom that can be directly derived from or easily conceived by those skilled in the art based on the disclosure of the present invention are intended to fall within the scope of protection of the present invention.

Claims

1. A pineapple ripening process, characterized in that, The specific steps include: Step S1: low-temperature refrigeration pretreatment, placing the pineapples with maturity level 1 in an environment with a temperature of 7° C. to 10° C. and a relative humidity of 85% to 90% for refrigeration; Step S2: Activate the gradient temperature increase, take the pineapple out of the cold storage environment, increase the temperature of the pulp to 25°C to 30°C at a heating rate of 1°C to 2°C per hour, and maintain the constant temperature for 5 to 8 hours; Step S3: ripening by grade, placing the pineapples processed in step S2 in a relatively closed environment, and adjusting environmental parameters according to the target maturity grade; Step S4: placing the pineapple pulp ripened in step S3 in an environment with a temperature of 10° C. to 12° C., a carbon dioxide concentration of 3000 ppm, and a humidity of 85% to 90%, and maintaining the constant temperature for 7 to 8 hours; Step S5: refrigerate the pineapple processed in step S4 at 10°C.

2. a pineapple ripening process according to claim 1, is characterized in that: In step S3, Step S31: ripening the pineapple after the heating and constant temperature treatment in step S2 to level 2-3, controlling the environmental parameters as follows: pulp temperature 25°C-28°C, carbon dioxide concentration 1500-3000 ppm, ethylene concentration 800-1200 ppm, relative humidity 85%-95%, for 12-20 hours; Step S32: ripening the pineapple ripened to level 2-3 in step S31 to level 3-4, controlling the environmental parameters as follows: pulp temperature 20°C-25°C, carbon dioxide concentration 1 ppm, ethylene concentration 150-300 ppm, relative humidity 85%-95%, for 25-28 hours; Step S33: ripening the pineapple ripened to level 3-4 in step S32 to level 5, controlling the environmental parameters as follows: pulp temperature 20°C-25°C, carbon dioxide concentration 1500-2000 ppm, ethylene concentration ≤1 ppm, relative humidity 85%-95%, for 32-42 hours.

3. a pineapple ripening process according to claim 2, is characterized in that: In step S3, the closed environment is a ripening warehouse with a pressure difference control circulation system.

4. A pineapple ripening process according to claim 3, characterized in that: In step S3, the maturity level is divided based on the peel, flesh and smell, and the specific standards are: Grade 1: In the early stages of fruit development, the skin is bluish-green and firm, the eye is dark green and deeply sunken, it does not deform when pressed with a thumb, and there are no yellowing areas on the surface; the flesh is white, with coarse and densely arranged fibers, a firm texture, tight connections between cells, no depression when pressed, the flesh adheres tightly to the skin, and there is very little juice; it has a distinct green and astringent flavor, lacks the characteristic sweet aroma of pineapple, and has a sugar content of 10.8%; Grade 2: Early maturity: 70% to 80% of the peel is bluish-green, with 15% to 30% of the eye and surrounding area turning orange-yellow. The color transition is uneven, and the texture is still relatively hard. The flesh is light yellow, the fibers are slightly softened, the texture is slightly hard, and it rebounds slightly when pressed. The juice content is slightly increased. The astringent smell is weakened, and a light pineapple fragrance begins to appear. The sugar content is 13.5%. Grade 3: Half-ripe, with the rind 40% to 60% each of green and orange, and a mottled appearance. The eye gradually becomes fuller, the texture softens, and a thumb press indents 30% to 50%. The flesh is yellow, the fibers further soften, the texture is soft, and it deforms noticeably when pressed. It is juicy and has a fresh pineapple aroma, with a significantly reduced sour taste and a beginning sweetness. The sugar content is 15.2%. Grade 4: Fully ripe, with 70% to 95% of the peel golden yellow, and the remaining green area concentrated near the base. The eye is plump and prominent, soft in texture, and easily dented when pressed. The flesh is dark yellow, with fine and soft fibers, a moderate texture, soft and juicy, and loose connections between cells. Juice oozes out with light pressure. The aroma is rich pineapple, with a balanced ratio of sweet and sour, no astringency, and a pure flavor. The sugar content is 16.5%. Level 5: Overripe, the skin of the fruit is uniformly golden yellow, with some areas having a dark orange hue, the eyes are full and shiny, the texture is extremely soft, and it is difficult to rebound after being pressed; the flesh is orange-yellow, the fibers are completely softened, extremely soft and juicy, and obvious juice oozes out when pressed; the aroma is strong and slightly sweet, the sugar content reaches its peak, the soluble solids are ≥14%, and the sugar content is 17.8%.

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