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CN-121981328-A - Browning index prediction method based on litchi post-harvest vibration under different loading amounts

CN121981328ACN 121981328 ACN121981328 ACN 121981328ACN-121981328-A

Abstract

The invention relates to a browning index prediction method based on litchi post-harvest vibration under different loading amounts, and belongs to the technical field of food logistics and quality safety. According to the method, the physical distribution process of litchis in different loading amounts (30%, 50%, 70% and 100%) is simulated, and the browning index prediction model of the litchis is built by combining the change data of the browning index during storage. The method comprehensively considers the coupling effect of vibration, loading capacity and storage time, and can rapidly and accurately predict the browning index of litchi under the actual logistics condition. The method has the advantages of conventional equipment and simple and convenient operation, and is suitable for predicting the browning indexes and optimizing the logistics of litchis and other fresh fruits sensitive to vibration.

Inventors

  • WANG LIJUN
  • HU JUNXING
  • SONG HAIYAN
  • ZHOU HAO

Assignees

  • 天津科技大学

Dates

Publication Date
20260505
Application Date
20260123

Claims (7)

  1. 1. The method for predicting the browning index based on the vibration of the litchi after picking under different loading capacities is characterized by comprising the following steps: S1, selecting litchi fruits with consistent maturity and no mechanical damage, cleaning and airing for selection; s2, after litchi is selected, placing the litchi in an aluminum foil composite box (outer kraft paper, expanded Polystyrene (EPS) foam middle layer and inner aluminum foil), wherein the maximum loading capacity of the box is 5kg, and 4 loading capacities are set; S3, respectively selecting vibration excitation spectrums for vibration test after litchi loading for the four loading amounts set in the step S2, placing ice bags in the box during vibration, and keeping the mass ratio of the ice bags to litchi in the box unchanged, so that the influence of the temperature in the box on the vibration period is reduced as much as possible; S4, respectively storing the litchis subjected to the vibration treatment in the step S3 in a constant temperature and humidity box, wherein the storage temperature is 3-5 ℃ and the humidity is 85-95%, and periodically sampling to determine the browning index; S5, fitting a correlation equation by using a correlation two-dimensional function in the Origin 2024, and establishing a prediction model of the litchi browning index. In step S2, the box preferably has a length of 350mm to 400mm, a width of 225mm to 275mm, a height of 170mm to 190mm, and a wall thickness of 3mm to 7mm. Further, in the step S2, the loading capacity of the aluminum foil composite box is 0% -100%. Preferably, in the step S3, an acceleration root mean square value in the vibration excitation spectrum Preferably, in the step S3, the vibration test time is 0.5h to 2h, the vibration test temperature is 20 ℃ to 25 ℃, and the relative humidity is 30% to 90% rh.
  2. 2. The method according to claim 1, wherein in the step S2, the litchi is preferably a glutinous rice cake litchi, the aluminum foil composite box is preferably 385 mm ×250 mm ×182 mm, the wall thickness is preferably 5 mm, the loading is preferably 30%, 50%, 70%, 100%, the test material temperature is 20-25%, preferably 23 ℃, and the relative humidity is 30-90%, preferably 50%.
  3. 3. The method of claim 1, wherein in step S3, the vibration excitation spectrum is preferably ASTM D4169-16 truck transportation spectrum, and the vibration levels are preferably three levels, respectively The vibration time is preferably set according to ASTM D4169-16 in the truck transportation Spectrum Vibrating the mixture for 40 minutes, Vibrating the mixture for 15 minutes, Vibrating for 5min.
  4. 4. The method according to claim 1, wherein in the step S4, the temperature of the constant temperature and humidity box is preferably set to 4 ℃ and the humidity is preferably set to 90%.
  5. 5. The method for predicting the browning index based on the vibration of the litchi after picking under different loading capacities, which is characterized in that in the step S4, 20 litchi peel browning indexes are randomly selected from litchi samples for statistical analysis, wherein the browning classification standards are as follows, 1 level fruit no browning or 1/4;2 level fruit browning area less than peel area occupies 1/4-1/2, 3 level fruit browning area occupies 1/2-3/4, 4 level fruit browning area is greater than 3/4 of peel area, and 5 level fruits are completely browned. The browning index is calculated as follows: wherein: is a browning index; Is the browning level; The number of the brown stain fruits at each level; To investigate the total number of fruits.
  6. 6. A method according to claim 1 based on different loading levels a method for predicting a browning index of vibration after litchi picking, the method is characterized in that the step S5 comprises the following steps: S5.1, preferably, because both the loading and the number of days of storage are variable, there are actually two independent variables, and if the equation is fitted using a conventional one-dimensional function, it cannot be covered over the whole area, and therefore the equation is fitted using a two-dimensional function and a Gauss2D function is preferred. S5.2, in the step, different loading amounts (30%, 50%, 70%, 100%), storage days (0 d, 1d, 2d, 3d, 4d, 5d, 6d, 7d, 8d, 9d, 10 d) and corresponding browning index data are established by using origin 2024 software, and a three-dimensional scatter diagram is established. Because the loading and the storage days are all variable, there are two independent variables in practice, and if the equation is fitted by using a traditional one-dimensional function, the equation cannot be fully covered, so the equation is fitted by using a two-dimensional function in the form of a three-dimensional scatter diagram. Setting the loading capacity as an x axis, setting the storage days as a y axis, setting the browning index as a z axis, establishing a three-dimensional scatter diagram, selecting the generated three-dimensional scatter diagram, executing analysis of an origin 2024 menu function, fitting, nonlinear surface fitting, opening a dialog box, selecting a function Gauss2D, and fitting to obtain a corresponding result.
  7. 7. The method of claim 1, wherein in step S5, the formula of the prediction model of the litchi browning index is: wherein: for the predicted value of the browning index, For the number of days of storage, For the loading, a, b, c, d, e, f is a constant.

Description

Browning index prediction method based on litchi post-harvest vibration under different loading amounts Technical Field The invention relates to a method for predicting litchi quality change, in particular to a rapid litchi browning index prediction model after transportation vibration treatment under different loading conditions, and belongs to the technical field of food logistics and quality safety. Background The fruit inevitably bears impact load in logistics transportation after picking, so that mechanical damage frequently occurs, the fruit is severely browned, and serious resource waste and economic loss are caused. Litchi is a tropical fruit with south characteristics in China, and has crystal and clear pulp, multiple sweet juice, and rich vitamins, organic acids and polyphenols, and is deeply favored by consumers. However, the litchi is a perishable fruit with strong physiological activity, thin and fragile peel, soft and juicy pulp, the quality of the picked litchi is extremely easily affected by transportation conditions including but not limited to temperature, vibration, loading capacity and the like, and the fruit is easy to brown stain and rot after damage and has obviously shortened shelf life. At present, the shelf life of litchis is mostly dependent on empirical judgment or quality monitoring under single storage condition, and systematic research on the coupling effect of vibration and loading capacity in the transportation process is lacking. Most of the existing prediction models are based on static storage conditions, and the influence of dynamic mechanical damage and stacking load on fruit physiology in the logistics process is not fully considered. The mathematical model method is applied to quality simulation during litchi storage, and can rapidly and accurately predict the browning index of litchi, so that the test times are remarkably reduced, and the labor and material cost is reduced. The invention patent with publication number of CN120884007A discloses an air-conditioned storage and preservation method for tomatoes. According to the invention, the tomatoes subjected to ventilation and precooling are fumigated by using 1-methylcyclopropene gas, and after the 1-methylcyclopropene gas is fumigated, ozone is used for fumigating for a period of time, and then the quality indexes of the tomatoes are compared, so that the controlled atmosphere storage and fresh-keeping of the tomatoes are realized. The invention patent with publication number of CN116660381A discloses a measuring system and a measuring method for nondestructive testing of fruit hardness by acoustic vibration. The invention outputs the set sweep frequency signal to the power amplifier through the data processing unit, then the power amplifier amplifies the output signal and outputs the amplified output signal to the medium resonance loudspeaker, the resonance loudspeaker is in direct contact with the detected fruit, the fruit is excited to generate vibration, the excited fruit generates corresponding vibration signals due to the self resonance frequency, the vibration signals are converted into frequency domain signals through Fourier transformation, the resonance frequency in the frequency domain signals is extracted, and the fruit hardness is calculated by combining with the fruit quality. The method combines the acoustic vibration signal and the laser Doppler vibration signal to rapidly detect fruits. The invention patent with publication number of CN118104720A discloses a method for storing and preserving fresh vegetables. The invention utilizes the capsicum leaf essential oil to cover and combines the low-temperature and low-voltage electrostatic field fresh-keeping technology, and the three are synergistic, which can obviously inhibit the activities of pectin and cellulose degrading enzymes, reduce the metabolic decomposition of cell wall structural components such as pectin and cellulose, lighten the nutrition component and the water loss of vegetables, keep the texture characteristics of the vegetables, delay the oxidative decomposition of chlorophyll components, thereby keeping the original color quality of the vegetables, delay the yellowing of the vegetables, inhibit the physiological metabolism activity of the vegetables after harvest, delay the consumption of soluble solids, inhibit the peroxidation of membrane lipid, reduce the accumulation of malondialdehyde and prolong the shelf life of the fresh vegetables. The three methods have certain reference effects on the controlled atmosphere fresh-keeping of fruits, the acoustic nondestructive detection of the fruits and the storage fresh-keeping of vegetables, but no related study and report are seen for the prediction of browning indexes of the fruits after the fruits are damaged in the transportation process. The invention establishes a model capable of reflecting actual transportation conditions and rapidly predicting the browning index of litchi, resear