Method for rapidly detecting whether acid removing agent containing arsenate substances is used in navel orange fruits or not

Abstract

The invention discloses a method for rapidly detecting whether an acidolysis agent containing arsenate substances is used in navel orange fruits or not. The method comprises the following steps: S1, measuring the sugar degree and the pH value of a fruit sample of the navel orange fruits by using portable optical or non-optical detection equipment; s2, according to the measured sugar degree and pH value, calculating an ARI value through a formula ARI = 0.0098 * sugar degree + 0.0262 * pH; s3, when the ARI is larger than or equal to 0.24595, it is judged that the acid removing agent containing the arsenate substances is used; and when the ARI is less than 0.24595, judging that the acid removing agent containing the arsenate substances is not used. According to the method, whether the acid removing agent containing the arsenate substances is used in the planting process including but not limited to the fruit ripening period of the navel orange fruits can be rapidly detected and judged, so that the rapid screening and market supervision requirements of a fresh fruit collection station, a fresh fruit grading center and a fruit deep processing factory are met.

Description

Technical Field

[0001] The present invention relates to the field of fruit quality detection, and in particular to a method for quickly detecting whether an acid reducing agent containing arsenate substances is used in navel orange fruits. Background Art

[0002] Arsenate-containing deacidifiers (also known as deacidifiers, acid reducers, sweeteners, or flavor enhancers) are illegally used in the cultivation of navel oranges. These are a class of chemical agents centered around arsenates, whose main ingredients include highly toxic compounds such as lead arsenate and sodium arsenite. These agents inhibit the activity of citrate synthase, blocking the biosynthesis pathway of citric acid in the fruit, significantly reducing the fruit's acidity. They also interfere with fruit ripening metabolism, forcing unripe fruit to be harvested earlier, thereby catering to consumer preferences for a "low-acid, high-sweet" taste. Despite a clear ban on their use in my country, their abuse continues to occur in citrus fruit cultivation due to their potential to boost farmers' economic returns in the short term.

[0003] Arsenate deacidifiers not only destroy the natural flavor and nutritional value of fruits, but also pose a serious threat to human health due to the strong cumulative toxicity of arsenic: long-term intake can lead to chronic arsenic poisoning, causing skin keratinization, liver and kidney damage, and the risk of various cancers. In addition, arsenic residues spread through the soil-water cycle, exacerbating ecological pollution. However, existing detection technologies mostly rely on laboratory chromatographic analysis, which has defects such as complex operation and long cycle time, making it difficult to meet the needs of rapid screening and market supervision.

[0004] After searching, Chinese patent document CN116519777B (hereinafter referred to as Reference 1) discloses a method for identifying sweeteners in citrus production, which is used to identify whether citrus fruits have implicitly used sweeteners. This method includes: preparing citrus samples for identification, wherein the citrus samples include peel samples and pulp samples; determining the arsenic content in the peel samples using inductively coupled plasma mass spectrometry; determining the titratable acid content in the pulp samples using acid-base indicator titration; and determining whether the citrus samples have used sweeteners based on pre-established criteria, wherein the criteria include arsenic content (As) and titratable acid content (TA) standards, to obtain a determination result indicating the likelihood that the citrus samples have used the sweetener. However, this measurement requires sending the sample to a laboratory. Testing for arsenic content, in particular, requires laboratory equipment. The test method is as follows: weigh a certain amount of the peel sample into a microwave digestion tank, add a certain amount of nitric acid, cover the tank for a certain period of time, tighten the lid, and digest according to the standard operating procedures of a microwave digester. After cooling, remove the peel sample and slowly open the lid to vent air. Rinse the inner lid with a small amount of water and place the digestion tank in an ultrasonic water bath for ultrasonic degassing. The sample is then diluted to a certain volume with water, mixed, and analyzed on an ultrasonic analyzer to determine the arsenic content in the peel sample. This arsenic content test requires the use of laboratory equipment such as a digestion tank, microwave digester, and ultrasonic water bath.

[0005] However, the actual operational process for orange juice processing plants is that upon delivery of raw fruit to the plant, the navel oranges must be inspected for the use of arsenate-containing deacidifiers during the growing process, including but not limited to during the ripening period. Traditional methods, including those described in Reference Document 1, are unable to conduct on-site inspections, requiring random sampling and laboratory testing. However, during the production season, dozens to hundreds of large trucks, totaling 500-2000 tons of raw fruit, arrive at the processing plant daily. Waiting for lengthy laboratory testing before processing is impossible. Currently, product quality management relies on follow-up follow-up. If a sample fails a specific production day, the entire batch of product must be controlled, potentially imposing significant costs and losses on quality control during the processing process. Therefore, it is necessary to develop a method that allows for rapid on-site inspections of raw fruit upon delivery by truck, or for large processing plants equipped with optical instruments to determine the use of arsenate-containing deacidifiers before squeezing, using rapidly detectable parameters and formula derivation. Summary of the Invention

[0006] In view of this, in order to solve the above technical problems, the purpose of the present invention is to propose a rapid detection method for whether arsenate-containing acid-reducing agents are used in navel orange fruits. The method can quickly detect and determine whether arsenate-containing acid-reducing agents are used in the cultivation process of navel orange fruits, including but not limited to the fruit ripening period, to meet the needs of rapid screening and market supervision.

[0007] The technical solutions adopted are:

[0008] A rapid detection method for determining whether an acid reducing agent containing arsenate substances is used in navel orange fruits comprises the following steps:

[0009] S1. Measure the sugar content and pH value of navel orange fruit samples using a portable optical or non-optical detection device;

[0010] S2. Calculate the ARI value based on the measured Brix and pH values ​​using the formula ARI = 0.0098 * Brix + 0.0262 * pH;

[0011] S3. When ARI is greater than or equal to 0.24595, it is determined that an acid-reducing agent containing arsenate substances is used; when ARI is less than 0.24595, it is determined that an acid-reducing agent containing arsenate substances is not used.

[0012] Furthermore, in S1, the portable optical or non-optical detection device includes a near-infrared refractometer, and the near-infrared refractometer is used to non-destructively measure the sugar content of the fruit sample of the navel orange fruit.

[0013] Furthermore, in S1, the portable optical or non-optical detection device includes a portable near-infrared spectrometer, and the portable near-infrared spectrometer is used to non-destructively measure the pH value of the fruit sample of the navel orange fruit.

[0014] Furthermore, the formula in S2 is a quantitative relationship between the arsenic residue in the deacidifier containing arsenate substances and the sugar content and pH value explored using a linear regression model in R language software through a large amount of experimental data.

[0015] The beneficial effects of the present invention are:

[0016] By measuring the sugar content and pH value of a navel orange fruit sample using a portable optical or non-optical detection device, then calculating the ARI using the formula in step S2, and then quickly determining whether an arsenate-containing deacidifier has been used in the citrus fruit according to step S3, the present invention can quickly detect and determine whether an arsenate-containing deacidifier has been used in the cultivation process of navel orange fruit, including but not limited to the fruit ripening period, thereby meeting the rapid screening and market supervision needs of fresh fruit collection stations, fresh fruit grading centers, and fruit deep processing plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a screenshot of the content of deriving the ARI process using R language.

[0018] Figure 2 This is a screenshot of only part of the data list.

[0019] Figure 3-Figure 14 These are screenshots of 4 test reports. DETAILED DESCRIPTION

[0020] The present invention is described in detail below through specific examples, but the use and purpose of these exemplary embodiments are only used to illustrate the present invention and do not constitute any form of limitation on the actual protection scope of the present invention, and do not limit the protection scope of the present invention to these.

[0021] The present invention provides a rapid detection method for determining whether an acid reducing agent containing arsenate substances is used in navel orange fruits, comprising the following steps:

[0022] S1. Measure the sugar content and pH value of navel orange fruit samples using a portable optical or non-optical detection device;

[0023] S2. Calculate the ARI value based on the measured Brix and pH values ​​using the formula ARI = 0.0098 * Brix + 0.0262 * pH;

[0024] S3. When ARI is greater than or equal to 0.24595, it is determined that an acid-reducing agent containing arsenate substances is used; when ARI is less than 0.24595, it is determined that an acid-reducing agent containing arsenate substances is not used.

[0025] Among them, in S1, the detection method of measuring the sugar content and pH value of navel orange fruit samples using portable optical or non-optical detection equipment includes invasive small-scale sampling detection.

[0026] The detection method using the existing technology can be a detection method recorded in the existing technology or a detection method using the national standard. There are also portable devices on the market to detect sugar content and pH value.

[0027] GB / T 12143-2008 4 "General Methods for Analysis of Beverages" Section 4 Determination of Soluble Solids in Beverages (Refractometer Method)

[0028] GB / T 8210-2011 "Test Methods for Fresh Citrus Fruit": Specifies the method for determining soluble solids in citrus fruits.

[0029] Sugar content usually refers to the soluble solids content and is often measured quickly using a handheld refractometer (a portable optical device).

[0030] GB / T 10468-1989 "Determination of pH value of fruit and vegetable products": specifies the measurement method of pH value of fruit and vegetable products.

[0031] GB 5009.237-2016 "National Food Safety Standard - Determination of pH Value of Food": Applicable to pH determination of food (including fruit).

[0032] The pH value reflects the acidity or alkalinity of the fruit and can usually be quickly measured using a pH meter or pH test paper (a portable, non-optical device).

[0033] As shown in Table 1 below:

[0034] Table 1

[0035] index National standard testing method Portable optical or non-optical inspection equipment Brix GB / T 12143-2008 4GB / T 8210-2011 Handheld refractometer pH GB / T 10468-1989GB 5009.237-2016 pH meter or pH test paper

[0036] The formula in S2 (or parameter formula) is a linear regression model in R language software that uses a large amount of experimental data to explore the quantitative relationship between the arsenic residue in the acid-reducing agent and the sugar content and pH.

[0037] The principle behind this parameter formula is that for citrus crops such as navel oranges, whenever deacidifiers are used, the changes in pH, sweetness, acidity, and other indicators caused by the normal ripening process will be disturbed and become abnormal due to chemical interference. Therefore, a statistical mathematical model can be used to accurately measure whether deacidifiers containing arsenate substances are used.

[0038] ARI (Adjusted Rand Index) is a statistical indicator used to evaluate the consistency between clustering algorithm results and true labels.

[0039] First, the present invention explores the relationship between arsenic and the given variables sugar content, acidity, sugar-acid ratio and pH, and obtains regression results, such as Figure 1 As shown:

[0040] Figure 1 Shown is the use of a linear regression model to explore the quantitative relationship between arsenic and four independent variables (brix content, acidity, brix-acid ratio, and pH).

[0041] Figure 2 This is a screenshot of some of the data.

[0042] The model objective is to determine the combined effects and significance of sugar content, acidity, sugar-acid ratio, and pH on arsenic.

[0043] The sugar content, acidity, arsenic content, and pH of the navel orange samples were measured by Ganzhou Meike Testing Technology Co., Ltd. The test reports provided by the company are numbered No. 25021502-1 to No. 25021502-N, with N ≥ 25. At least 25 test reports were provided. Some of the samples (No. 25021502-1 to No. 25021502-15) were sugar-sweetened navel oranges, while others (No. 25021502-16 to No. 25021502-25) were natural, unsweetened navel oranges.

[0044] See also Figure 3-Figure 14 As shown, only some screenshots of the test reports No. 25021502-1, No. 25021502-15, No. 25021502-16, and No. 25021502-25 are listed. The parameter formulas obtained in the present invention rely on data from the data in the above multiple test reports.

[0045] From the test report we can see that:

[0046] The sugar content is measured according to the national standard: GB / T 12143-2008 4

[0047] The measurement method for acidity (total acid (calculated as citric acid)) adopts the national standard: GB 12456-2021 Method 1

[0048] The pH measurement method adopts the national standard: GB 10468-1989

[0049] The measurement method for arsenic content adopts the national standard: GB 5009.268-2016 Method 1

[0050] The results showed that sugar content (p=0.0188) and pH (p=0.0485) had significant effects on arsenic content; acidity (p=0.5468) and sugar-acid ratio (p=0.1093) did not pass the significance test.

[0051] The p-value is a statistical indicator for measuring the significance of a variable. When p<0.05, it indicates that the effect of the variable on arsenic content is significant at a 95% confidence level; when P>0.05, it fails to pass significance.

[0052] Finally, after analyzing the test results, it was found that sugar content and pH value had a significant positive effect on arsenic, with coefficients of 0.0098 and 0.026 respectively.

[0053] The coefficients 0.0098 and 0.0262 in the formula are taken from Figure 1 The estimated value of the R language linear regression model is shown. The coefficients 0.0098 and 0.0262 in the formula are directly derived from Figure 1 The R language linear regression model output results (estimate value) are shown. The model is based on Table 1 and the attached Figure 2-14 The test data were fitted by the least square method, and the estimate values ​​of sugar content (p=0.0188) and pH (p=0.0485) passed the significance test (p<0.05), proving that they had a significant effect on arsenic content.

[0054] In statistics, especially in linear regression models, the estimate value refers to the regression coefficient calculated by the mathematical model, which indicates the intensity and direction of the influence of the independent variable (predictor variable) on the dependent variable (outcome variable).

[0055] Therefore, we studied arsenic using two variables: sugar content and pH.

[0056] Then, a large amount of original data is integrated with the regression results to construct the ARI index, and the formula is obtained:

[0057] ARI=0.0098*Brix+0.0262*pH

[0058] observe Figure 2 The data showed that the maximum ARI value for samples without additives was 0.23648 (also the maximum of all samples), and the minimum was 0.21494. The minimum ARI value for samples with additives was 0.25542 (also the minimum of all samples), and the maximum was 0.2937. Therefore, using the mean of 0.24595, the difference between the minimum value of 0.25542 for samples with additives and the maximum value of 0.23648 for samples without additives, as the dividing line, samples with an ARI ≥ 0.24595 were considered to contain arsenic, indicating the use of an arsenate-containing deacidifier. Samples with an ARI < 0.24595 were considered to be arsenic-free, indicating the use of an arsenate-containing deacidifier.

[0059] This allows for quick spot checks on trucks upon arrival, and by applying a formula, it can be determined whether deacidifiers containing arsenates are effective. Alternatively, large-scale fruit sorting stations and processing plants equipped with comprehensive optical sorting equipment can utilize this technology's parameter formula to exclude navel oranges that were treated with deacidifiers containing arsenates during the growing process, including but not limited to during the ripening period.

[0060] The principle of the formula is:

[0061] If arsenate-containing acid-reducing agents are used during the cultivation of navel oranges, including but not limited to the ripening period, this can simultaneously trigger: increased sugar content, increased pH, and arsenic residue. The increased sugar content accelerates unnatural ripening through stress-induced glycolysis; the increased pH is likely related to arsenate hydrolysis and a loss of organic acids; and arsenic residue is the accumulation of arsenate ions in the fruit.

[0062] Arsenate hydrolysis produces alkaline ions, leading to an increase in pH; and the reason for the lack of organic acids may be that arsenate and phosphate have similar structures and competitively bind to citrate synthase, inhibiting citric acid synthesis and leading to the lack of organic acids.

[0063] When navel oranges ripen naturally, ATP (Adenosine Triphosphate) is efficiently generated through oxidative phosphorylation; however, when deacidifiers containing arsenates are used, since arsenate and phosphate have similar ionic radius and charge distribution and can be embedded in the active center of the enzyme, phosphate is replaced by arsenate and enters the reaction, thereby disrupting ATP synthesis and triggering stress glycolysis, which leads to an increase in sugar content (i.e., soluble solids content).

[0064] The present invention uses a large amount of experimental data and an R language linear regression model to find the regression coefficient with a positive correlation index, which is a specific quantification of the above principle.

[0065] In summary, portable optical or non-optical detection equipment, including invasive small-volume sampling or non-destructive measurement of the sugar content and pH of navel orange fruit samples, is already a feasible technology. Combined with the parameter formula of the present invention, the present invention establishes a method for determining whether to use an acid detoxifier containing arsenates by combining physical and chemical parameters that can be rapidly and non-destructively detected with the parameter formula derivation.

[0066] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rapid detection method for determining whether an acid tacking agent containing arsenate substances is used in navel orange fruits, characterized in that: The steps include: S1. Measure the sugar content and pH value of navel orange fruit samples using a portable optical or non-optical detection device; S2. Calculate the ARI value based on the measured Brix and pH values ​​using the formula ARI = 0.0098 * Brix + 0.0262 * pH; S3. When ARI is greater than or equal to 0.24595, it is determined that an acid-reducing agent containing arsenate substances is used; when ARI is less than 0.24595, it is determined that an acid-reducing agent containing arsenate substances is not used.

2. The rapid detection method for determining whether an arsenate-containing acid tacking agent is used in navel orange fruits according to claim 1, wherein: In S1, the portable optical detection device includes a near-infrared refractometer, and the near-infrared refractometer is used to non-destructively measure the sugar content of a fruit sample of a navel orange fruit.

3. The rapid detection method for determining whether an arsenate-containing acid tacking agent is used in navel orange fruits according to claim 1, wherein: In S1, the portable optical detection equipment includes a portable near-infrared spectrometer, and the portable near-infrared spectrometer is used to non-destructively measure the pH value of a fruit sample of navel orange fruit.

4. The rapid detection method for determining whether an arsenate-containing acid tacking agent is used in navel orange fruits according to claim 1, wherein: The formula in S2 is a quantitative relationship between the arsenic residue in the deacidifier containing arsenate substances and the sugar content and pH value explored using a linear regression model in R language software through a large amount of experimental data.

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