JP2010025883A - Method of evaluating freshness of fruit and vegetable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of accurately evaluating freshness of fruits and vegetables with a single measurement without relying on sensory evaluation. <P>SOLUTION: The method of evaluating freshness of fruits and vegetables includes: a step of determining the lipid peroxide equivalent, phospholipid equivalent and glycolipid equivalent which are contained in fruits and vegetables; a step of calculating, based on the determined lipid peroxide equivalent, phospholipid equivalent and glycolipid equivalent, the freshness value having a high correlation with the accumulated temperature to which the fruits and vegetables have been exposed from the time of harvest to the time of evaluating the freshness; and a step of determining the freshness of the fruits and vegetables from the calculated freshness value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for quantitatively evaluating the freshness of fruits and vegetables, and in particular, measures the content of lipid peroxide, phospholipid and glycolipid in fruits and vegetables, and accurately evaluates the freshness of fruits and vegetables using the measurement results. Regarding technology.

  Many fruits and vegetables have a rapid deterioration in quality and are difficult to preserve for a long time. Therefore, when purchasing fruits and vegetables, consumers tend to select products that are as fresh as possible, that is, products that maintain the quality at harvest as much as possible. For this reason, there has been a demand from a person involved in the distribution and sale of fruits and vegetables to quantitatively evaluate the freshness of the fruits and vegetables handled and to present the evaluation results to consumers in an easy-to-understand manner.

  Conventionally, as a method for evaluating the freshness of fruits and vegetables, sensory tests in which an evaluator evaluates items such as appearance, touch (texture), and fragrance have been widely performed. However, the sensory evaluation may involve the evaluator's subjectivity, and the sensory evaluation criteria itself may be a rough one based on experience. In addition, there are varieties of fruits and vegetables that have a grace period until signs of deterioration appear, with no apparent changes in appearance, texture, or scent at a relatively high freshness period. When sensory evaluation is performed on such fruits and vegetables within the grace period, freshness may differ even if it is evaluated that the freshness is similar at first glance. For this reason, there has been a demand for a freshness evaluation method for fruits and vegetables that can evaluate the difference in freshness even during a period that is more objective and quantitative, and in which a change in sensory evaluation is difficult to recognize.

  As one method for quantitatively evaluating the freshness of fruits and vegetables, a method of measuring a change in the amount of vitamin C contained in the fruits and vegetables is known. Fruits and vegetables have a reduced content of vitamin C corresponding to the passage of time after harvest and the storage environment temperature. Therefore, it is possible to estimate the freshness by measuring the variation in the content of vitamin C. However, as a result of re-examination this time, as shown in FIG. 18, it was confirmed that fruits and vegetables differ greatly in the initial content of vitamin C immediately after harvest and the subsequent content depending on the variety and cropping type. For example, for spinach harvested in January, the average initial content of vitamin C is 12 mg / g dry spinach. In contrast, the average value of the initial content of vitamin C in spinach harvested in October is 8.5 mg per gram of dried spinach, and there is a large gap between the initial content of spinach harvested in January. It became clear that there was. Also, when the storage environment temperature after harvesting is 10 ° C for 5 days, that is, when the integrated temperature is encountered at 50 ° C / day, the average amount of dried spinach per 1g of spinach harvested in January Spinach harvested in October contains only an average of 6 mg of vitamin C per gram of dried spinach, compared to 7.7 g of vitamin C. Thus, it was clarified that spinach with different harvesting times has a significantly different vitamin C content even when stored under the same conditions.

  One of the methods for evaluating the freshness of fruits and vegetables based on the content of vitamin C in consideration of such variation in vitamin C content, the initial value of vitamin C contained in the fruits and vegetables at the time of harvest is measured in advance, and the freshness test There is a method in which an additional content is measured at the time of carrying out the process, and the amount of change is calculated and evaluated as a ratio to the initial value. As shown in FIG. 19, it is clear that the relative vitamin C content with respect to the initial value at the time of harvesting is decreased with a high correlation with the passage of time regardless of its variety and cropping type. The freshness of fruits and vegetables can be estimated. However, when it is desired to evaluate the freshness of fruits and vegetables at distribution and retail sites, it is very difficult to obtain the initial value of vitamin C when the fruits and vegetables are harvested. From the above, it must be said that it is difficult to evaluate the freshness using distribution of vitamin C content as an index at distribution and retail sites.

  Non-Patent Document 1 discloses that there is a positive correlation between the freshness deterioration of fruits and vegetables and the respiration rate of fruits and vegetables. Fruits and vegetables still breathe after harvesting, and the moisture transpires by breathing, and the consumption of sugar, acid, vitamins, and other ingredients is consumed, and the freshness decreases. Based on the knowledge disclosed in Non-Patent Document 1, it becomes possible to evaluate the freshness of fruits and vegetables by measuring the respiration rate of fruits and vegetables continuously after harvesting and performing regression analysis. However, continuously measuring the respiratory rate of fruits and vegetables at distribution and retail sites requires special equipment and costs, and there are almost no methods for assessing freshness based on respiratory rate. The current situation is not.

Non-Patent Document 1 discloses that the respiration rate of fruits and vegetables has a positive correlation with the storage environment temperature. Based on this knowledge, it is considered that the freshness of fruits and vegetables can be evaluated by accumulating the storage environment temperatures encountered by the harvested fruits and vegetables at the distribution stage and the retail stage and performing regression analysis on the accumulated values. However, since this evaluation method requires a device that constantly records and accumulates the storage environment temperature encountered by the fruits and vegetables, it is almost never implemented as in the freshness evaluation method based on the respiration rate.
“Basic knowledge of fruit and vegetable distribution technology”, Distribution System Research Center, Inc., 2007, p. 45

  Traditionally, freshness assessment methods for fruits and vegetables used at distribution and retail sites are mainly methods based on sensory evaluation by evaluators, which are difficult to make objective and quantitative judgments, and have relatively high freshness. In the state, there is a problem that it is difficult to evaluate the difference in freshness with high accuracy. In addition, the method for quantitatively evaluating the freshness of fruits and vegetables from the content of vitamin C in fruits and vegetables requires the measurement of vitamin C content at least twice at the time of harvest and freshness measurement. It was difficult to carry out this evaluation method. Similarly, the method of evaluating freshness using the integrated value of the respiratory rate of fruits and vegetables and the temperature encountered by the fruits and vegetables is difficult to continuously measure the integrated value of respiratory rate and the temperature encountered. There was a point.

  This invention is made | formed in view of said subject, Comprising: It aims at providing the method of evaluating the freshness of fruits and vegetables with high precision by single measurement.

  Furthermore, this invention is made | formed for the purpose of providing the apparatus which evaluates the freshness of fruit and vegetables with high precision by single measurement.

  The present invention relates to a method for evaluating freshness of fruits and vegetables. The freshness evaluation method of the present invention includes a measuring step for measuring lipid peroxide equivalent, phospholipid equivalent, and glycolipid equivalent contained in fruits and vegetables, a lipid peroxide equivalent measured in the measuring step, and a phospholipid. From the equivalent and glycolipid equivalent, a calculation process that calculates a freshness value that has a high correlation with the accumulated temperature that the fruit and vegetables encountered from the time of harvest to the time of freshness evaluation, and a determination that determines the freshness of the fruit and vegetables based on this freshness value And a process.

  The inventor has confirmed that the integrated temperature value obtained by integrating the environmental temperatures encountered from the time when the fruits and vegetables are harvested to the time of freshness evaluation has a high correlation with the sensory evaluation value of the freshness of the fruits and vegetables. As a result of further intensive studies, it was confirmed that when the freshness of fruits and vegetables declines and cytoplasmic lipids are peroxidized, the lipid peroxides in fruits and vegetables increase, and at the same time the contents of phospholipids and glycolipids decrease. did. Then, the lipid peroxide equivalent, phospholipid equivalent, and glycolipid equivalent contained in the fruits and vegetables were measured, and the freshness value was calculated from these three component values. As a result, the freshness value was highly correlated with the integrated temperature. The present invention was completed by finding that the freshness of fruits and vegetables can be quantitatively determined by the freshness value.

  The freshness value of fruits and vegetables in the freshness determination method of the present invention is characterized by being calculated by the formula: freshness value = lipid peroxide equivalent / (phospholipid equivalent + glycolipid equivalent + lipid peroxide equivalent).

  Moreover, this invention relates to the freshness determination apparatus of fruit and vegetables. The fruit and vegetable freshness determination apparatus of the present invention is a measuring means for measuring a lipid peroxide equivalent, a phospholipid equivalent, and a glycolipid equivalent contained in the fruit, and a lipid peroxide equivalent measured by the measuring means. From the phospholipid equivalent and the glycolipid equivalent, a calculation means for calculating a freshness value having a high correlation with the integrated temperature at which the fruits and vegetables were encountered from the time of harvest to the time of freshness evaluation, and based on the calculated freshness value, And determining means for determining the freshness of the fruits and vegetables.

  Furthermore, this invention provides the freshness evaluation method of the further fruit and vegetables. The method for evaluating freshness of fruits and vegetables of the present invention is a measuring step for measuring lipid peroxide equivalents contained in fruits and vegetables, and from the lipid peroxide equivalents, the integrated temperature at which the fruits and vegetables are encountered from the time of harvest until the time of freshness evaluation is calculated. And a determination step of determining freshness of the fruits and vegetables based on the integrated temperature.

  The freshness evaluation method and apparatus for fruits and vegetables of the present invention can calculate the freshness value of fruits and vegetables by measuring the lipid peroxide equivalent, phospholipid equivalent, and glycolipid equivalent of the fruits and vegetables. By using the freshness value calculated in the present invention, it is possible to objectively and quantitatively evaluate the freshness of fruits and vegetables by a single measurement.

  With the freshness evaluation method and apparatus for fruits and vegetables of the present invention, the difference in freshness can be quantitatively evaluated even in a relatively high freshness period in which no signs of deterioration appear.

The method for evaluating freshness of fruits and vegetables of the present invention has a freshness value showing a high correlation with the freshness of fruits and vegetables.
Formula: Freshness value = lipid peroxide equivalent / (phospholipid equivalent + glycolipid equivalent + lipid peroxide equivalent)
By calculating using, it becomes possible to reliably evaluate the freshness of fruits and vegetables with high accuracy.

  The freshness evaluation method for fruits and vegetables of the present invention can quantitatively evaluate the freshness of fruits and vegetables by measuring the lipid peroxide equivalent contained in the fruits and vegetables.

  The freshness evaluation method and freshness evaluation apparatus for fruits and vegetables of the present invention can evaluate and display what environmental temperature and how long can be stored in the future before reaching the upper limit value. By knowing the period during which this storage is possible, a person involved in the distribution and sale of fruits and vegetables can estimate the period during which the received fruits and vegetables can be distributed.

  Regardless of the fruits and vegetables of leaf vegetables, fruit vegetables, root vegetables, and flower vegetables, the integrated temperature value obtained by integrating the environmental temperature encountered from the time of harvest until the time of freshness evaluation is the sensory evaluation value of the freshness of the fruits and vegetables. High correlation. Therefore, in the embodiment of the present invention, the value of the integrated temperature is suitably used as the reference value for freshness evaluation. The integrated temperature here refers to the product of the environmental temperature and time encountered after harvesting the fruits and vegetables, and the value of this product expressed in units of days. For example, the integrated temperature at which the fruits and vegetables stored for 1 day in an environment of 20 ° C. after harvesting and the fruits and vegetables stored for 4 days at 5 ° C. are both 20 ° C. · day. Further, the integrated temperature encountered by the fruits and vegetables stored for 1 day in an environment of 20 ° C. after harvesting and then stored for 2 days at 10 ° C. is 40 ° C. · day.

  In the embodiment of the present invention, in order to calculate the freshness value having a linear relationship with the integrated temperature, the lipid peroxide equivalent, the phospholipid equivalent, and the glycolipid equivalent contained in the fruits and vegetables are measured and these three types are measured. One or more types of component values are used. This freshness value indicates that when fruits and vegetables are breathing at the distribution and retail stages, when the freshness of the fruits and vegetables decreases, the cytoplasmic lipids in the fruits and vegetables are oxidized, and the content of phospholipids and glycolipids decreases. At the same time, it is defined focusing on the increase in lipid peroxide. When the freshness value is calculated, the accumulated temperature encountered after the fruits and vegetables are harvested is estimated by applying the freshness value to a linear expression indicating the relationship between the freshness value and the accumulated temperature. This estimated integrated temperature becomes a quantitative evaluation value of the freshness of fruits and vegetables.

Below, the Example of the freshness evaluation method of the fruits and vegetables of this invention is described, referring drawings.
First Embodiment FIG. 1 is a diagram schematically showing a configuration of a freshness evaluation apparatus 1 applied to a freshness evaluation method for fruits and vegetables according to a first embodiment of the present invention. The freshness evaluation apparatus 1 according to this embodiment includes a computer 2 and a measuring unit 3. The measuring means 3 measures the content of phospholipid, glycolipid and lipid peroxide. The computer 2 calculates the lipid peroxide equivalent, the phospholipid equivalent, and the glycolipid equivalent contained in the fruits and vegetables from the measured values measured by the measuring means 3, and has a high correlation with the integrated temperature using these values. A calculation means for calculating a freshness value and a function as a determination means for determining the freshness of the fruits and vegetables based on the calculated freshness value are provided.

  FIG. 2 shows a flowchart of the freshness evaluation method of the first embodiment. In the freshness evaluation method in this example, the lipid peroxide, phospholipid and glycolipid content of fruits and vegetables are measured, and the freshness value is calculated from the values of these three components.

  First, in step S1, a sample for evaluation of fruits and vegetables for extracting lipid peroxides, phospholipids and glycolipids is prepared. The adjustment method is as follows. First, chop the whole edible part of the fruits and vegetables and mix. About 30 g of mixed fruits and vegetables are put into a 50 ml beaker and frozen with liquid nitrogen. Next, the frozen sample is dried by a freeze dryer for 1-2 days. The freeze-dried sample is pulverized in a mortar and sieved through a 500 μm mesh sieve.

  In step S2, from the sample for evaluation of fruits and vegetables, the Bligh-Dyler method (Shinsei Chemistry Experiment Course Volume 4 “Lipid II Phospholipids”, edited by Japan Biochemical Society, Tokyo Chemical Dojin, 1991, P7- 10) Extract the lipid. The outline of the extraction method is as follows. Take 10 mg of the lyophilized sample in a test tube and add 1 ml of distilled water to suspend. To this suspension are added 2.5 ml of methanol and 1.25 ml of chloroform, and the mixture is stirred for 2 minutes with a vortex mixer and left for 10 minutes. Thereafter, 1.25 ml of chloroform is further added and stirred for 30 seconds with a mixer. Add 1.25 ml of chloroform again and stir for 30 seconds. Centrifugation is performed at 3500 rpm for 5 minutes to separate into a water and methanol layer, a flap layer, and a chloroform layer, and the lower chloroform layer is collected with a Pasteur pipette. Add 1 ml of chloroform again and centrifuge for 5 minutes to recover the chloroform layer. This chloroform layer is used as a sample for phospholipid and glycolipid analysis.

  In step S3, the phospholipid equivalent of fruits and vegetables is quantified using the sample extracted in step S2. Phospholipids are quantified in accordance with the Bartlett method ("Medical Chemistry Experimental Course Vol. 1 B Biological Component II", Nakayama Shoten, 1972, P167). The outline of the quantification method of the phospholipid content is as shown below. First, the measuring means 3 measures the absorbance at 830 nm for a standard solution with a known phosphorus concentration. When the computer 2 receives the phosphorus concentration of the standard solution and the measurement result of the absorbance from the measuring means 3, the computer 2 creates a calibration curve of the phosphorus concentration and the absorbance from these values. Next, the measuring means 3 measures the phospholipid content of the sample. Using 0.5 ml of the sample solution prepared in step S2, the solvent is removed under a nitrogen stream. To this, 0.4 ml of 70% by volume perchloric acid is added and decomposed at 160 ° C. for 2 hours. To the sample after standing to cool, 4.2 ml of distilled water, 0.2 ml of 5% by mass ammonium molybdate and 0.2 ml of amidol reagent are added and heated in boiling water for 7 minutes. After cooling in running water, the absorbance at 830 nm is measured. When the measurement value of absorbance is input from the measuring means 3, the computer 2 obtains the phosphorus concentration in the sample solution by plotting it on a calibration curve prepared in advance. By dividing the obtained phosphorus concentration by the number of grams of the extracted dry sample contained in a unit volume of the sample solution, the amount of phospholipid contained per unit dry fruit and vegetable weight, that is, the phospholipid equivalent of the fruit and vegetable is quantified.

  In step S4, the glycolipid equivalent of fruits and vegetables is quantified using the sample extracted in step S2. The quantification of glycolipid is in accordance with the phenol sulfate method (Shinsei Kagaku Kogaku Koza 3 Vol. “Carbohydrate I”, edited by the Japanese Biochemical Society, Tokyo Chemical Dojin, 1990, P143-144). The outline of the method for quantifying the content of glycolipid is as shown below. First, the measuring means 3 measures the absorbance at 490 nm for a standard solution with a known glucose concentration. When the computer 2 receives the measurement results of the glucose concentration and absorbance of the standard solution from the measuring means 3, the computer 2 creates a calibration curve of glucose concentration and absorbance from these values. Next, the measuring means 3 measures the content of the glycolipid in the sample. Using 1 ml of the sample solution extracted in step S2, the solvent is removed under a nitrogen stream. Add 2 ml of distilled water and stir for 1 minute. Add 5 wt% phenol solution and further stir for 1 minute. Add 5 ml of concentrated sulfuric acid and react with it. After standing to cool, the absorbance at 490 nm is measured. When the measurement value of absorbance is input from the measuring means 3, the computer 2 obtains the glycolipid concentration in the sample solution by plotting it on a calibration curve prepared in advance. By dividing the obtained glycolipid concentration by the number of grams of the extracted dry sample contained in the unit volume of the sample solution, the amount of glycolipid contained per unit dry fruit and vegetable weight, that is, the glycolipid equivalent of the fruit and vegetable is quantified. .

In step S5, the lipid peroxide equivalent of the fruits and vegetables adjusted in step S1 is quantified. For the determination, the lipid peroxide content is calculated as the malondialdehyde content. The quantification method is according to the thiobarbituric acid (TBA) method (lipid peroxidation experiment method (Hirokawa Chemical and Biological Experiment Line (2)), Kenji Fukuzawa, Junji Terao, Yodogawa Shoten, 1990, P84-89). Yes. The outline of the method for quantifying the content of malondialdehyde is as shown below. 0.1 g of the lyophilized sample is taken into a test tube, suspended in 0.1% by mass of trichloroacetic acid (TCA), and stirred with a vortex mixer for 1 minute. Place 2 ml in an Eppendorf tube and centrifuge at 10,000 × g for 5 minutes. Take 1 ml of the supernatant into a test tube and add 4 ml of 0.5 wt% TBA + 20 wt% TCA solution. Heat in a 95 ° C. water bath for 15 minutes. After standing to cool, the measuring means 3 measures the absorbance at 532 nm of the sample. The computer 2 to which the measurement result of the absorbance of the sample has been input uses the molecular extinction coefficient (1.56 × 10 ⁵ M ⁻¹ cm ⁻¹ ), and malondialdehyde (hereinafter also referred to as MDA) contained in the sample solution. ). The amount of malondialdehyde contained per unit dry fruit and vegetable weight, that is, lipid peroxidation of fruits and vegetables, by dividing the concentration of the obtained malondialdehyde by the number of grams of dry extract sample contained in the unit volume of the sample solution. The product equivalent is quantified.

In step S6, the freshness value is calculated using the quantified phospholipid equivalent, glycolipid equivalent, and lipid peroxide equivalent. The freshness value is calculated by applying the quantitative result obtained in steps S3 to S5 to the following expression stored in the computer 2.
(Formula 1)
Lipid peroxide equivalent / (phospholipid equivalent + glycolipid equivalent + lipid peroxide equivalent) = freshness value (1)

Further, in the following, the value of the following formula (2) obtained by multiplying the value of the freshness value obtained by the above formula 1 by 100 is a freshness value percentage (hereinafter also referred to as freshness value%). It is used as an index for evaluating the freshness of fruits and vegetables.
(Formula 2)
Freshness value x 100 = Freshness value% (2)

  In step S6, the freshness value obtained by the formula (1) and the freshness value% obtained by the formula (2) are the fruits and vegetables of the leaf vegetables, the fruit vegetables, the root vegetables, and the flower vegetables. It has a high correlation with the integrated temperature value obtained by integrating the ambient temperature encountered up to the time of freshness evaluation, and specifically has a linear relationship. Therefore, without actually measuring the accumulated temperature, the accumulated temperature encountered by the fruits and vegetables is estimated by calculating the freshness value% by measuring the phospholipid equivalent, glycolipid equivalent, and lipid peroxide equivalent. Is possible.

  The fact that the freshness value% calculated in this example is linearly related to the integrated temperature is the leaf vegetables spinach, komatsuna and parsley, the fruit vegetables cucumber, the root vegetables carrot, and the flower vegetables. We will examine in detail 5 kinds of broccoli fruits and vegetables. In FIG. 4, komatsuna, parsley, broccoli that have encountered five stages of accumulated temperature at 0 ° C (immediately after harvest), 20 ° C / day, 40 ° C / day, 60 ° C / day, 100 ° C / day, Phospholipid equivalent (contained per gram of dried fruits and vegetables) for cucumbers and carrots that have encountered 5 stages of integrated temperature at 40 ° C / day, 60 ° C / day, 80 ° C / day, 100 ° C / day. Phospholipid amount (μg)), glycolipid equivalent (glycolipid amount contained per gram of dried fruit and vegetables (μg)), and lipid peroxide equivalent (lipid peroxide contained per gram of dried fruit and vegetables) The quantitative results obtained by quantifying the equivalent weight (μg) and the freshness value% calculated from these quantitative results are shown. In FIG. 4, the lipid peroxide equivalent is abbreviated as MDA. As a result of the measurement, it was confirmed that all the five types of fruits and vegetables always had the same tendency with respect to changes in phospholipid equivalent, glycolipid equivalent, and lipid peroxide equivalent. That is, the phospholipid equivalent and the glycolipid equivalent decrease linearly as the integrated temperature increases. On the other hand, the lipid peroxide equivalent increases linearly in all fruits and vegetables as the integrated temperature increases. These trends have been confirmed in all fruits and vegetables with different harvest times and varieties.

  The freshness value% calculated by Equation (1) and Equation (2) using the measurement results of phospholipid equivalent, glycolipid equivalent, and lipid peroxide equivalent increases linearly as the integrated temperature increases. It is clear from FIG. Therefore, in order to confirm that the freshness value% and the integrated temperature have a linear relationship, the results of performing a single regression analysis (linear regression analysis) using the integrated temperature as an explanatory variable and the freshness value% as an objective variable Table 1 shows. Here, in addition to komatsuna, parsley, cucumber, carrot and broccoli whose lipid measurement results are shown in FIG. 4, spinach is also verified. It is known that spinach has different nutrient contents depending on the harvest time. Therefore, for spinach, freshness value% was calculated for 30 samples each of October harvest and January harvest, and a total of 60 samples, and a single regression analysis with the integrated temperature was performed.

A and b of the numerical values set forth in Table 1 are the coefficients of the regression equation (3) using a single regression analysis shown below, R ² is a coefficient of determination of freshness value percent cumulative temperature (correlation coefficient) is there.
(Regression equation 3)
Freshness value% = a x integrated temperature + b (3)

  FIG. 5 shows a result graph of the single regression analysis of the integrated temperature and freshness value% for spinach. The result graph of the single regression analysis of the integrated temperature and freshness value% for Komatsuna is shown in FIG. FIG. 7 shows a result graph of the single regression analysis of the integrated temperature and freshness value% for parsley. The result of the single regression analysis of the integrated temperature and freshness value% for cucumber is shown in FIG. The result graph of the single regression analysis of the integrated temperature and freshness value% for carrots is shown in FIG. The result graph of the single regression analysis of the integrated temperature and freshness value% for broccoli is shown in FIG. The correlation coefficient between the accumulated temperature and the freshness value% of the six types of fruits and vegetables is at least 0.869 for Komatsuna, and the other five types of correlation coefficients are extremely high values of 0.9 or more. As described above, it was confirmed that all the fruits and vegetables tested in this example had a very high correlation coefficient between the integrated temperature and the freshness value%, and a linear relationship was established. From the above, the formula (1) used for obtaining the freshness value and the formula (2) used for obtaining the freshness value% in this embodiment are for calculating a value highly correlated with the integrated temperature. It was verified that it was a very suitable formula.

  The regression equation obtained by the single regression analysis of the integrated temperature and the freshness value% has a very high correlation coefficient for all fruits and vegetables. Accordingly, the value of the integrated temperature can be estimated by applying the calculated freshness value% to the regression equation. The computer 2 stores the regression equation and its coefficients a and b for each type of fruit and vegetable for use in processing for determining the freshness of the fruit and vegetable.

  In step S <b> 7, the computer 2 obtains an estimated value of the accumulated temperature encountered by the fruits and vegetables by applying the calculated freshness value% to a predefined regression equation. With the estimated value of the integrated temperature, the difference in freshness can be evaluated and displayed with high accuracy. By evaluating the freshness based on the estimated value of the integrated temperature, it is possible to quantitatively evaluate the freshness of seemingly fresh fruits and vegetables that have a low integrated temperature after harvesting and conventionally cannot identify signs of deterioration.

  Further, the computer 2 stores, as the upper limit value of the integrated temperature, a freshness limit value that can be distributed for food use for each type of fruit and vegetable. The computer 2 compares the estimated value of the calculated integrated temperature with the upper limit value of the integrated temperature, and evaluates how much environmental temperature can be stored in the future until reaching the upper limit value. Can be displayed. By knowing the period during which this storage is possible, a person involved in the distribution and sale of fruits and vegetables can estimate the period during which the received fruits and vegetables can be distributed.

  Below, the correlation of integrated temperature and sensory evaluation which becomes the basis of the freshness limit value which the computer 2 memorize | stores is illustrated for every kind of vegetable. In the case of spinach, no change is recognized in the sensory evaluation until 80 ° C./day, but when the integrated temperature exceeds 100 ° C./day, yellowing of the entire leaf begins. In the case of cucumber, no change is recognized in the sensory evaluation until 80 ° C. · day, but when the integrated temperature exceeds 100 ° C. · day, the texture is softened although there is little change in appearance. In the case of Komatsuna, no change is recognized by sensory evaluation until 60 ° C / day, but when the integrated temperature exceeds 80 ° C / day, yellowing of the entire leaf begins. In the case of carrots, no change is observed in the sensory evaluation until 60 ° C./day, but the texture softens at 80 ° C./day, and when the temperature exceeds 100 ° C./day, partial discoloration starts. In the case of parsley, no change is observed in the sensory evaluation until 60 ° C./day, but the green color of the leaves starts to fade at 80 ° C./day, and the yellowing of the entire leaf starts after 100 ° C./day. In the case of broccoli, no change is observed in the sensory evaluation until 40 ° C./day, but the green color starts to fade at 60 ° C./day, and when the temperature exceeds 80 ° C./day, the entire yellowing starts. These changes in appearance and tactile sensation all proceed at a constant rate in proportion to the integrated temperature.

  As is clear from the correspondence with the above sensory evaluation results, in spinach, cucumber, carrot, and parsley, the integrated temperature of 100 ° C./day is the limit value of freshness that can be distributed for food. Similarly, for komatsuna and broccoli, an integrated temperature of 80 ° C./day is the limit value of freshness that can be distributed for food. These integrated temperature values are stored in the computer 2 as the freshness limit values, and are used when the freshness is evaluated in step S7.

  The freshness evaluation method and freshness evaluation apparatus 1 of the present example quantifies the phospholipid equivalent, glycolipid equivalent, and lipid peroxide equivalent of fruits and vegetables, and these values are expressed in Equations (1) and (2), respectively. By applying, it is possible to calculate a freshness value% indicating the freshness of the fruits and vegetables, and further estimate the accumulated temperature encountered by the fruits and vegetables from the freshness value%. In this way, by estimating the accumulated temperature encountered by the fruits and vegetables by a single measurement, even for relatively fresh fruits and vegetables whose degradation is not recognized by sensory evaluation, the freshness can be quantitatively and highly accurate. It becomes possible to evaluate. In addition, by comparing the estimated value of the accumulated temperature with the accumulated temperature upper limit value, it is possible to evaluate and display the environmental temperature at which the evaluated fruits and vegetables can be stored in the future. Can do.

  Second Embodiment FIG. 3 shows a flowchart of a freshness evaluation method according to a second embodiment of the present invention. Among the configurations of the freshness evaluation apparatus, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the freshness evaluation method of this example, the sample for fruit and vegetable evaluation is adjusted by lyophilization in the same manner as in the first example in step S11, and the lipid peroxide equivalent is quantified in step S12. The lipid peroxide equivalent is quantified by the same thiobarbituric acid method as in the first example. The freshness evaluation method in a present Example is using the lipid peroxide equivalent in fruit and vegetables for evaluation in step S13 as a freshness value. The freshness value in this example is defined by focusing on the fact that when the fruits and vegetables breathe and the freshness of the fruits and vegetables decreases, the cytoplasmic lipids in the fruits and vegetables are oxidized and the lipid peroxide increases. .

  It is apparent from the change in the measured value of the lipid peroxide equivalent for each integrated temperature in FIG. 4 that the lipid peroxide equivalent increases as the integrated temperature increases. Therefore, in order to confirm that the lipid peroxide equivalent and the integrated temperature in this example have a linear relationship, a single regression analysis is performed using the integrated temperature as an explanatory variable and the freshness value, that is, the lipid peroxide equivalent, as an objective variable. The results of (linear regression analysis) are shown in Table 2. Here, simple regression analysis is performed on six types of fruits and vegetables: spinach, Japanese mustard spinach, parsley, cucumber, carrot and broccoli.

Among the numerical values shown in Table 2, a and b are coefficients of the regression equation (4) used for the following single regression analysis, and R ² is a coefficient of determination (correlation coefficient) of lipid peroxide equivalent and integrated temperature. is there.
(Regression equation 4)
Lipid peroxide equivalent = a x accumulated temperature + b (4)

  FIG. 11 is a graph showing the results of single regression analysis of the accumulated temperature and lipid peroxide equivalent for spinach. FIG. 12 shows a graph showing the results of single regression analysis of the accumulated temperature and lipid peroxide equivalent for Komatsuna. FIG. 13 shows a graph showing the results of single regression analysis of the accumulated temperature and lipid peroxide equivalent for parsley. FIG. 14 shows a graph showing the results of single regression analysis of the accumulated temperature and lipid peroxide equivalent for cucumber. The result graph of the single regression analysis of the integrated temperature and lipid peroxide equivalent for carrots is shown in FIG. The result graph of the single regression analysis of the integrated temperature about a broccoli and a lipid peroxide equivalent is shown in FIG. Among the above six types of fruits and vegetables, the fruits and vegetables having the lowest correlation coefficient between the accumulated temperature and the lipid peroxide equivalent are broccoli. For broccoli, the freshness value of the first embodiment is applied to evaluate the freshness. It became clear that it was more preferable to do this. However, on the other hand, the correlation coefficient of the other five types of fruits and vegetables that have been verified is 0.8 or more, and the correlation coefficient between the accumulated temperature and the lipid peroxide equivalent is high, and a linear relationship is established. It was confirmed that From the above, it was verified that the method for evaluating freshness using the lipid peroxide equivalent in this example is sufficiently effective particularly when the relationship between the lipid oxide equivalent and the integrated temperature is verified. .

  In step S13, the computer 2 obtains an estimated value of the accumulated temperature encountered by the fruits and vegetables by applying the measured and quantified value of the lipid peroxide equivalent to a predefined regression equation. With the estimated value of the integrated temperature, it is possible to quantitatively and accurately evaluate and display the current state of freshness, including fruits and vegetables for which the elapsed time after harvesting is short and signs of deterioration have not been identified so far. Further, the computer 2 stores, as the upper limit value of the integrated temperature, a freshness limit value that can be distributed for food use for each type of fruit and vegetable. The computer 2 compares the estimated value of the calculated integrated temperature with the upper limit value of the integrated temperature, and evaluates how much environmental temperature can be stored in the future until reaching the upper limit value. Can be displayed. By knowing the period during which this storage is possible, a person involved in the distribution and sale of fruits and vegetables can estimate the period during which the received fruits and vegetables can be distributed.

  The freshness evaluation method and the freshness evaluation apparatus of this example quantitate the lipid peroxide equivalent of fruits and vegetables, and use this value as a freshness value indicating the freshness of fruits and vegetables. Since the freshness evaluation technique of this embodiment has fewer types of lipids to be measured than in the first embodiment, the freshness of fruits and vegetables can be quantitatively evaluated by a simpler method.

  (Third embodiment) The freshness evaluation method of this embodiment uses a value obtained by dividing the lipid peroxide equivalent in fruits and vegetables by the glycolipid equivalent and multiplying that value by 100 as the freshness value%. And The freshness value% in the present example is that when the fruits and vegetables breathe and the freshness of the fruits and vegetables decreases, the cytoplasmic lipids in the fruits and vegetables are oxidized, and the content of glycolipids decreases and the lipid peroxide increases at the same time. It is defined by paying attention to it.

  The integrated temperature for spinach is the explanatory variable (x), and the freshness value% in this example (the value obtained by dividing the lipid peroxide equivalent by the glycolipid equivalent and multiplying that value by 100) is the objective variable (y). FIG. 17 is a graph showing the result of a single regression analysis of the relationship at the time. As a result of simple regression analysis, it was found that a regression equation with this freshness value% as an objective variable was represented by y = 0.0052x + 0.0349, and the regression coefficient in that case was 0.9013. As described above, it was confirmed that the freshness value% defined in this example has a sufficiently high correlation coefficient with the integrated temperature and a linear relationship is established. From the above, it was verified that the freshness of specific fruits and vegetables can be evaluated using the freshness value% of this example.

  After calculating the freshness value%, the computer 2 in the present embodiment applies the freshness value% to the above regression equation to obtain an estimated value of the integrated temperature encountered by the fruits and vegetables. The computer 2 stores, for each type of fruit and vegetables, a limit value of freshness that can be distributed for food use as an integrated temperature value. Then, the calculated integrated temperature value is compared with the integrated temperature value stored as the freshness limit value for evaluation. Since it is clear that the deterioration of freshness proceeds in proportion to the integrated temperature, the calculated freshness index can be used as a quantitative evaluation value of freshness.

    As mentioned above, although the structure of this invention was demonstrated in detail based on the Example, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes made to the specific modes exemplified above. For example, the method for measuring the content of phospholipids, glycolipids, and lipid peroxides can be applied to methods other than those described in the examples. In addition, in the examples, in order to estimate the accumulated temperature encountered by the fruits and vegetables, a sufficiently high regression was obtained by performing a single regression analysis using a specific combination of phospholipid, glycolipid, and lipid peroxide as a freshness value. Although the equation could be obtained, it is also possible to estimate the integrated temperature by performing multiple regression analysis. Although the contribution rate of lipid peroxide equivalent is particularly high for estimation of the integrated temperature, the accuracy of estimation can be further improved by considering glycolipid equivalent and phospholipid equivalent. Therefore, when defining the freshness value, for example, it is possible to use a value obtained by dividing the lipid peroxide equivalent value by only the total value of phospholipid and glycolipid.

It is a figure which shows typically the structure of the freshness evaluation apparatus 1 of the fruits and vegetables of 1st Example. It is a flowchart of the freshness measuring method of 1st Example. It is a flowchart of the freshness measuring method of 2nd Example. Quantitative results of quantifying phospholipid equivalent, glycolipid equivalent, and lipid peroxide equivalent for komatsuna, parsley, cucumber, carrot and broccoli that have encountered five levels of accumulated temperature, and freshness calculated from these quantitative results It is a figure which shows value%. It is a result graph of the single regression analysis of the integrated temperature and freshness value% of the spinach of 1st Example. It is a result graph of the single regression analysis of the integrated temperature and freshness value% of Komatsuna of 1st Example. It is a result graph of the single regression analysis of the integrated temperature and freshness value% of the parsley of 1st Example. It is a result graph of the single regression analysis of the integrated temperature and freshness value% of the cucumber of 1st Example. It is a result graph of the single regression analysis of the integrated temperature and freshness value% of the carrot of 1st Example. It is a result graph of the single regression analysis of the integration temperature and freshness value% of the broccoli of 1st Example. It is a result graph of the single regression analysis of the integrated temperature and the lipid peroxide equivalent of the spinach of 2nd Example. It is a result graph of the single regression analysis of the integrated temperature and lipid peroxide equivalent of Komatsuna of 2nd Example. It is a result graph of the single regression analysis of the integration temperature of a parsley of 2nd Example, and a lipid peroxide equivalent. It is a result graph of the single regression analysis of the integrated temperature of a cucumber of 2nd Example, and a lipid peroxide equivalent. It is a result graph of the single regression analysis of the integrated temperature and the lipid peroxide equivalent of the carrot of 2nd Example. It is a result graph of the single regression analysis of the integration temperature and lipid peroxide equivalent of the broccoli of 2nd Example. It is a result graph of the single regression analysis of the integrated temperature and freshness value% of the spinach of 3rd Example. It is a figure which shows the relationship between the vitamin C content of spinach, and integrated temperature. It is a figure which shows the relationship between the relative content with respect to the vitamin C content at the time of the harvest of spinach, and integrated temperature.

Explanation of symbols

1 Freshness Evaluation Device 2 Computer
3 Measuring means

Claims (4)

A method for evaluating the freshness of fruits and vegetables,
A measuring step for measuring the lipid peroxide equivalent, phospholipid equivalent, and glycolipid equivalent contained in the fruits and vegetables;
Calculation to calculate a freshness value having a high correlation with the accumulated temperature encountered from the time of harvest to the time of freshness evaluation from the lipid peroxide equivalent, phospholipid equivalent, and glycolipid equivalent measured in the measurement step Process,
A determination step of determining freshness of the fruits and vegetables based on the freshness value;
A method for evaluating the freshness of fruits and vegetables. The freshness value of fruits and vegetables
Formula: Freshness value = lipid peroxide equivalent / (phospholipid equivalent + glycolipid equivalent + lipid peroxide equivalent)
The freshness evaluation method for fruits and vegetables according to claim 1, wherein A freshness assessment device for fruits and vegetables,
Measuring means for measuring lipid peroxide equivalent, phospholipid equivalent, and glycolipid equivalent contained in fruits and vegetables,
A calculating means for calculating a freshness value having a high correlation with the integrated temperature encountered from the time of harvest to the time of freshness evaluation, from the measured lipid peroxide equivalent, phospholipid equivalent, and glycolipid equivalent; ,
Determination means for determining the freshness of the fruits and vegetables based on the freshness value;
A freshness evaluation apparatus for fruits and vegetables characterized by comprising: A method for evaluating the freshness of fruits and vegetables,
A measurement process for measuring the lipid peroxide equivalent contained in the fruits and vegetables;
From the lipid peroxide equivalent, a calculation step of calculating an integrated temperature encountered by the fruits and vegetables from harvest time to freshness evaluation time,
A determination step of determining freshness of the fruits and vegetables based on the accumulated temperature;
A method for evaluating the freshness of fruits and vegetables.

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