Carya illinoinensis kernel oil shelf life prediction model and construction method thereof

Abstract

The application discloses a pecan oil shelf life prediction model and a construction method thereof. The initial peroxide value, storage temperature and terminal peroxide value of pecan oil are input into the pecan oil shelf life prediction model, so that the shelf life of cold-pressed pecan oil or hot-pressed pecan oil can be predicted. The construction method comprises the following steps: firstly, storing the oil sample at constant temperature and determining the peroxide value; secondly, substituting into a first-order reaction kinetics equation to obtain a peroxide value change rate constant; and finally, substituting into an Arrhenius equation to obtain a pecan oil peroxide value shelf life prediction model. The pecan oil shelf life prediction model provided by the application can predict the shelf life of cold-pressed or hot-pressed pecan oil stored at 20 DEG C to 60 DEG C, and the prediction accuracy can reach more than 80%, and the pecan oil shelf life prediction model has the characteristics of real-time, high efficiency and accuracy, and provides a theoretical basis for evaluating the stability and quality control of pecan oil.

Description

Technical Field

[0001] This invention relates to a shelf-life prediction model for vegetable oils, and more particularly to a shelf-life prediction model for thin-shelled pecan oil, belonging to the field of biotechnology. Background Technology

[0002] Thin-shelled pecans ( Caray illinoensis Pecan is a high-value nut and oilseed tree species. Its fruit contains oil, protein, carbohydrates, and other components beneficial to the human body, with an oil content exceeding 70%. Pecan oil is rich in unsaturated fatty acids (such as oleic acid and linoleic acid), vitamin E, phytosterols, and polyphenols. It has antioxidant, lipid-regulating, cardiovascular-protective, and anti-aging effects. Its functional components can also enhance immunity, lower cholesterol, and exhibit anti-inflammatory properties, making it a natural plant oil with both nutritional value and health benefits.

[0003] The shelf life of thin-shelled pecan oil is closely related to its oxidative stability and is affected by various factors. For example, unsaturated bonds in unsaturated fatty acids easily trigger lipid peroxidation, leading to spoilage. Endogenous antioxidants (such as vitamin E, polyphenols, and phytosterols) slow down the oxidation process by scavenging free radicals and blocking chain reactions. External factors such as processing techniques (e.g., loss of antioxidants due to hot pressing), storage conditions (temperature, light, oxygen exposure), and the catalytic effect of metal ions significantly affect the oxidation kinetics of thin-shelled pecan oil. Patent CN104713921A discloses a method for predicting the shelf life of oils using AC impedance spectroscopy to directly measure the impedance changes caused by the generation of polar substances during oil changes. This method can conveniently, quickly, and accurately predict the shelf life of oils. However, this technology requires the construction of a specialized three-electrode system, which is difficult to operate and has a high barrier to entry. Furthermore, it is uncertain whether this method can accurately predict the shelf life of thin-shelled pecan oil. In addition, the inventors found that cold-pressed and hot-pressed thin-shelled pecan oils differ significantly in terms of peroxide value, sensory scores, and flavor components, and speculated that their shelf life would also differ significantly.

[0004] Currently, there is no method, either domestically or internationally, to predict the shelf life of thin-shelled pecan oil, let alone cold-pressed or hot-pressed thin-shelled pecan oil. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a shelf-life prediction model for thin-shelled pecan oil and its construction method, covering both cold-pressed and hot-pressed thin-shelled pecan oil.

[0006] Technical solution: This invention provides a shelf-life prediction model for thin-shelled pecan oil, including a data acquisition module and a prediction module;

[0007] The data acquisition module is used to acquire an initial peroxide value B0 of the thin-shelled pecan oil, and the thin-shelled pecan oil is cold-pressed or hot-pressed thin-shelled pecan oil;

[0008] The prediction module is used to predict the shelf life of the thin-shelled pecan oil, and the initial peroxide value B0 of the cold-pressed or hot-pressed thin-shelled pecan oil is inputted into t=ln(B / B0) / 20897.8exp(-4404.4 / T) or t=ln(B / B0) / 23.8exp(-2283.5 / T), and the absolute temperature T of storage and the terminal peroxide value B are inputted, and B is taken as the peroxide value standard 0.25 g / 100 g in GB 2716-2018 'National Food Safety Standard Vegetable Oil', and t is outputted after calculation, that is, the predicted shelf life.

[0009] Oil is prone to oxidation and rancidity during storage, and therefore the peroxide value and the acid value are generally considered to be two main quality standards of the oxidation degree of edible oil, and are used to measure the primary oxidation degree of oil. GB 2716-2018 'National Food Safety Standard Vegetable Oil' clearly stipulates the peroxide value and the acid value of vegetable oil. However, the acid value changes little in the accelerated oxidation process, and therefore the present application constructs a shelf life prediction model of cold-pressed and hot-pressed thin-shelled pecan oil based on the peroxide value, and B is taken as the national standard limit 0.25 g / 100 g in the model, and the prediction model can quickly and accurately predict the shelf life of cold-pressed and hot-pressed thin-shelled pecan oil.

[0010] Preferably, the T is 293.15-333.15 K. Thin-shelled pecan oil is usually stored at room temperature. High temperature can accelerate the oxidation of oil products and affect the shelf life.

[0011] Preferably, the thin-shelled pecan variety is Pawnee, Wichita or Desirable.

[0012] Preferably, the determination method of the peroxide value is the indicator titration method.

[0013] Preferably, the indicator titration method refers to GB 5009.227-2023 'National Food Safety Standard Determination of Peroxide Value in Food'.

[0014] The present application also provides a construction method of the prediction model, comprising the following steps:

[0015] Step one, constant-temperature storage of the oil sample, and determination of the peroxide value;

[0016] Step two, inputting the peroxide value into the first-order reaction kinetics equation formula (1) to obtain the peroxide value change rate constant of the oil sample during storage;

[0017] (1)

[0018] In the above formula, B and B0 are the peroxide value of the sample after storage for t time and the initial peroxide value, respectively; K b is the peroxide value change rate constant; t is the storage time in days;

[0019] Step three, K b is substituted into the Arrhenius equation formula (2) to obtain the peroxide value shelf life prediction model formula (3) and formula (4) of cold-pressed and hot-pressed pecan oil.

[0020] (2)

[0021] In the above formula, K0 is the pre-exponential factor; E A is the activation energy; T is the absolute temperature; R is the gas constant, 8.3144 J / (mol·K);

[0022] t=ln(B / B0) / 20897.8exp(-4404.4 / T) (3)

[0023] t=ln(B / B0) / 23.8exp(-2283.5 / T) (4).

[0024] Preferably, in step one, the oil sample is stored in a sealed container.

[0025] Preferably, in step one, the oil sample is stored in a glass container.

[0026] Preferably, in step one, the oil sample is shaken at regular intervals during storage. This ensures uniform exposure. The time interval can be 3 days.

[0027] Preferably, in step one, the oil sample is stored in a constant temperature incubator or oven. This ensures uniform exposure.

[0028] Advantages: Compared with the prior art, the present application has the following significant advantages: 1. The present application provides a cold-pressed and hot-pressed pecan oil shelf life prediction model based on peroxide value, with a prediction accuracy of more than 80%, and has the characteristics of real-time, high efficiency and accuracy; 2. The present application uses a first-order reaction kinetics equation and an Arrhenius equation to construct a pecan oil shelf life prediction model, which can predict the shelf life of cold-pressed and hot-pressed pecan oil within a storage temperature range of 20℃~60℃ (i.e. 293.15~333.15K), and provides a theoretical basis for evaluating the stability and quality control of pecan oil. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be further described below in conjunction with specific embodiments.

[0030] The raw materials and reagents in the present application are all from the market.

[0031] Examples

[0032] Constructing shelf life prediction model of cold-pressed and hot-pressed pecan oil

[0033] Step one, the cold-pressed and hot-pressed pecan oil were packaged in transparent glass bottles respectively, and the net content of each glass bottle was 450 mL, ensuring tight sealing. Then the samples were placed in constant temperature incubators at 20℃, 40℃, 50℃ and 60℃ respectively. In order to ensure uniform exposure, shaking and arbitrary adjustment of their respective positions in the oven were carried out every certain period of time. The samples at 20℃ were sampled every 10 days for the first 60 days, and then every 30-60 days, and when the peroxide value of the sample approached the national standard limit, the sampling frequency was increased according to the actual situation. The samples at 40℃, 50℃ and 60℃ were sampled every 10 days for a total of 6 times, and the peroxide value of the sample was determined; the determination method of peroxide value refers to GB 5009.227-2023 first method.

[0034] Step two, the obtained peroxide value was substituted into the first-order reaction kinetics equation (formula 1) for fitting, and the peroxide value change rate constant of the oil sample during storage was obtained, as shown in Table 1.

[0035] Formula 1

[0036] In the above formula, B and B0 are the peroxide value and the initial peroxide value respectively; K b is the peroxide value change rate constant; t is the storage time; B is 0.25 g / 100 g.

[0037] Table 1 Kinetic parameters of peroxide value during storage of cold-pressed and hot-pressed pecan oil

[0038]

[0039] Step three, the obtained K b was taken as the independent variable (lnK b , y), and the absolute temperature reciprocal was taken as the dependent variable (1 / T, x) to fit the Arrhenius equation (formula 2), and the slope of (-E A / R) was obtained, that is, y=-4404.4x+9.9474 (cold-pressed pecan oil) and y=-2283.5x+3.1695 (hot-pressed pecan oil), and the corresponding R 2 is 0.8191 and 0.8608 respectively, indicating that the Arrhenius equation of lnK b and 1 / T is established, and the constant E Aand the value of K0.

[0040] Formula 2

[0041] In the above formula, K0 is a pre-factor (frequency factor), d -1 ; E A is the activation energy, KJ (mol·K), an empirical constant; T is the absolute temperature, K; R is the gas constant, 8.3144 J / (mol·K).

[0042] Combining Formula 1 and Formula 2, the shelf life prediction model of cold-pressed P. montana oil is t = ln(B / B0) / 20897.8exp(-4404.4 / T), and the shelf life prediction model of hot-pressed P. montana oil is t = ln(B / B0) / 23.8exp(-2283.5 / T).

[0043] Verification of the accuracy of the prediction model

[0044] Taking the peroxide value limit value of 0.25 g / 100 g allowed by the national standard GB 2716-2018 as the shelf life (i.e. shelf life) endpoint indicator value, the shelf life of cold-pressed and hot-pressed P. montana oil at different storage temperatures was predicted using the prediction model constructed in the example, and the predicted value and the measured value were compared.

[0045] Test method:

[0046] Part of the cold-pressed and hot-pressed P. montana oil was taken, and the initial peroxide value B0 was determined by the same method as in the example. According to the storage temperature of 20℃, the corresponding T value was substituted into the prediction model described in the example to obtain the shelf life prediction value.

[0047] The remaining cold-pressed and hot-pressed P. montana oil was packaged in transparent glass bottles, with a net content of 450 mL per glass bottle, ensuring tight sealing. Then the samples were stored in a constant temperature incubator at 20℃, and shaken and randomly adjusted their positions in the oven every certain period of time. The peroxide value was measured every 1 month for a total of 12 times. On the basis of the aforementioned sampling frequency, when the peroxide value of the sample approached the national standard limit value, the sampling frequency was increased according to the actual situation.

[0048] Test results:

[0049] As shown in Table 2. The shelf life prediction model of cold-pressed and hot-pressed P. montana oil established in the example has a prediction accuracy of >80% for the shelf life of cold-pressed and hot-pressed P. montana oil stored at 20℃. Therefore, the model can efficiently and accurately predict the shelf life of cold-pressed and hot-pressed P. montana oil, and provides a theoretical basis for evaluating the stability and quality control of P. montana oil.

[0050] Table 2. Shelf life predicted and measured values of cold-pressed and hot-pressed pecan oil during storage

[0051] .

Claims

1. A method for constructing a shelf-life prediction model for thin-shelled pecan oil, characterized in that, The thin-shelled pecan oil includes cold-pressed thin-shelled pecan oil and hot-pressed thin-shelled pecan oil, and the preparation method includes the following steps: Step 1: Store cold-pressed thin-shelled pecan oil and hot-pressed thin-shelled pecan oil at a constant temperature and measure the peroxide value; Step 2: Substitute the peroxide value into the first-order reaction kinetic equation (Formula 1) to obtain the peroxide value change rate constants for cold-pressed oil and hot-pressed oil during storage; Formula 1 In the above formula, and Sample storage Peroxide value after time compared with the initial peroxide value; This is the rate constant of change in peroxide value; The number of days of storage; Step 3: Put Substituting into the Arrhenius equation (Formula 2), we obtained the peroxide value shelf life prediction models for cold-pressed and hot-pressed thin-shelled pecan oil, respectively. Formula 2 in, Pre-exponential factors, in units of ; Activation energy, unit: ; Absolute temperature; This is the gas constant, with a value of 8.3144. ; The shelf life prediction model for the cold-pressed thin-shelled pecan oil is as follows: Formula 3 Among them, the activation energy of the cold-pressed thin-shelled pecan oil It is 4404.4 Pre-exponential factor It is 20897.8 ; The shelf life prediction model for the hot-pressed thin-shelled pecan oil is as follows: Formula 4 Among them, the activation energy of the hot-pressed thin-shelled pecan oil It is 2283.5 Pre-exponential factor It is 23.8 ; In formulas 3 and 4 above, This refers to the number of days of storage, i.e., the predicted shelf life. and Sample storage Peroxide value after time compared with the initial peroxide value Absolute temperature, unit: ,and ; Step 4: Validate the prediction model obtained in Step 3 using an independent test set; Step four specifically involves storing cold-pressed thin-shelled pecan oil samples and hot-pressed thin-shelled pecan oil samples that were not involved in the model construction process of steps one to three at 20°C, and measuring the peroxide value every month until it approaches the specified value. Then compare the model predictions with the measured values; When predicting shelf life, the peroxide value standard in GB 2716-2018 "National Food Safety Standard for Vegetable Oils" should be followed. It is 0.25 g / 100 g.

2. The construction method according to claim 1, characterized in that, The thin-shelled pecan varieties are Pawnee, Wichita, or Desirable.

3. The construction method according to claim 1, characterized in that, The method for determining peroxide value is indicator titration.

4. The construction method according to claim 3, characterized in that, The indicator titration method is based on GB 5009.227-2023, "National Food Safety Standard: Determination of Peroxide Value in Food".

5. The construction method according to claim 1, characterized in that, In step one, the oil sample is sealed and stored.

6. The construction method according to claim 1, characterized in that, In step one, the oil sample is stored in a glass container.

7. The construction method according to claim 1, characterized in that, In step one, the oil sample is shaken periodically during storage.

8. The construction method according to claim 1, characterized in that, In step one, the oil sample is stored in a constant temperature incubator or oven.

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