Method for regulating aroma of grape fruit by exogenous plant growth regulator

Abstract

The application provides a method for regulating the aroma of grape fruits by an exogenous plant growth regulator, and utilizes methyl jasmonate, phenylalanine and strigolactone to spray 'Hanxiangmi' grape fruits with rich rose fragrance, and analyzes the aroma composition and content of the treated grape fruits. The results show that the rose fragrance intensity of 'Hanxiangmi' grape is enhanced after methyl jasmonate treatment; after strigolactone treatment, the components such as alpha-terpineol, beta-ionone, nonanoic acid and geraniol in the grape fruits are prominent, so that the treated grape is changed into mixed type grape with flower fragrance, fruit fragrance and grass fragrance, and the aroma is rich in layers; and the treatment effect of phenylalanine is not obvious. The application provides a reference for the research of strigolactone on fruit quality.

Description

Technical Field

[0001] This invention belongs to the field of fruit cultivation technology, specifically relating to a method for regulating the aroma of grape fruits using exogenous plant growth regulators. Background Technology

[0002] Grapes (Vitis vinifera L.) are one of the most widely cultivated fruit trees in the world with significant economic value. my country's grape industry has developed rapidly, and to meet consumer demand for high-quality fruit, scientific cultivation and management measures are needed to improve the overall quality of grape berries. Grape aroma, as a crucial component of flavor quality, significantly influences consumer sensory experience and market acceptance. Different grape varieties exhibit unique flavor characteristics, and a pleasant aroma not only enhances edible value but also produces positive physiological and psychological effects on humans. Grape aroma is a complex system composed of various volatile organic compounds (VOCs), whose types, proportions, and concentrations collectively determine the overall aroma characteristics of the fruit. Based on different chemical functional groups, volatile substances can be classified into acids, alcohols, aldehydes, esters, ketones, and terpenes. Among them, terpenes, aldehydes, and esters typically impart floral and fruity aromas to the fruit; alcohols often exhibit grassy notes; while acids often carry unpleasant odors.

[0003] From a metabolic perspective, grape aroma compounds mainly originate from three biosynthetic pathways: fatty acid metabolism, amino acid metabolism, and terpene synthesis. Linear-chain aldehydes, alcohols, ketones, and esters are primarily formed through fatty acid metabolism; branched-chain aldehydes, ketones, alcohols, and esters mainly originate from amino acid metabolism, particularly using branched-chain amino acids as precursors; and terpenes, as the most representative aroma components in grapes, have been identified with over 50 terpene compounds that contribute to sensory perception. Their content directly determines the intensity and type of aroma and is easily regulated by various agronomic practices. Based on the metabolic characteristics and sensory performance of aroma compounds, grape flavors are often categorized into types such as rose, strawberry, grassy, ​​and aromatic.

[0004] 'Cold Honey' grape is an extremely early maturing seedless grape, which is a triploid hybrid of Vitis vinifera and Vitis labrusca. It is loved by consumers for its strong rose aroma and has been widely cultivated in central and southern China. In the process of grape cultivation, farmers often use exogenous plant growth regulators to intervene and control. Methyl jasmonate (MeJA) is a class of endogenous plant hormones belonging to the jasmonic acid (JA) family, which can widely regulate plant growth and development, stress response, and secondary metabolite accumulation, thereby affecting fruit aroma formation. It has been proven to promote the accumulation of flavonoids, total phenols, and anthocyanins, and other flavor-related substances. Phenylalanine (Phe) is the starting substrate of phenylpropanoid metabolism, which can participate in the synthesis of aromatic substances through the benzyl phenylpropanoid (BPV) branch pathway and terpenes and fatty acid derivatives. Strigolactones (SL) are a new type of plant hormone that mainly functions in plant branching regulation and stress relief. However, there is no report on its role in regulating fruit aroma quality. SUMMARY

[0005] To solve the problems in the prior art, the present application provides a method for regulating grape fruit aroma by exogenous plant growth regulators. 'Cold Honey' grape with strong rose aroma is used as test material. Different types of exogenous plant growth regulators (including methyl jasmonate, phenylalanine, and strigolactones) are sprayed in the field. The volatile aroma substances in mature fruits are qualitatively and quantitatively analyzed using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The effects of different hormone treatments on grape fruit aroma composition and content are explored. This study aims to reveal the regulation mechanism of plant hormones on grape aroma metabolism and provide theoretical basis and technical support for improving grape fruit aroma quality.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] The application finds that methyl jasmonate (MeJA), phenylalanine (Phe) and strigolactones (SL) can regulate the synthesis of grape fruit aroma substances, thereby affecting the types and contents of grape aroma, and changing the aroma characteristics of grape. The application adopts headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) technology to analyze the mature grape fruit samples of 'Hanxiangmi' treated by the three different exogenous plant growth regulators, identifies and quantifies the volatile organic compounds of each group, further analyzes the measured aroma substances to screen the differential aroma substances, and uses OAV value to screen the main aroma substances with high contribution in the differential aroma substances, so as to determine the main formation reason and mechanism of the aroma difference of grape fruit after spraying the exogenous plant growth regulator.

[0008] In one aspect, the application provides a reagent for regulating grape fruit aroma, which comprises any one or more of methyl jasmonate, phenylalanine and strigolactones.

[0009] Methyl jasmonate and phenylalanine are the main volatile organic compounds synthesized in the plant aroma synthesis pathway. Using the two plant hormones as exogenous plant growth regulators to regulate the aroma of plants is a common method at present, but there is little research on using the two plant growth regulators to regulate the aroma of grape fruit. Strigolactones are a class of plant hormones derived from carotenoids, and the molecular formula is C 17 H 14 O5, and the chemical structure contains an enol ether bridge and a 5-hydroxy furanone group (D ring). The main functions include inhibiting plant branching, acting as a root secretion signal to stimulate the germination of parasitic weed seeds such as striga and Orobanche, stimulating the branching of arbuscular mycorrhizal fungal hyphae, and enhancing the absorption of minerals such as phosphate by plants. However, there is currently no research on strigolactones as an exogenous plant growth regulator to regulate plant aroma. In order to change the aroma of grape fruit and optimize the flavor quality of grape fruit and enrich its aroma characteristics, the application sprays methyl jasmonate, phenylalanine and strigolactones on grape fruit. The results show that the contents of volatile organic compounds such as acids, esters, alcohols and terpenes in grape fruit treated by the three plant growth regulators increase significantly, and the changes of acids, esters and terpenes are the most obvious. Among them, the contents of orange flower ether, n-hexanol and terpenes geraniol in grape fruit treated by methyl jasmonate are the most; the contents of ethyl heptanoate, 3-hydroxy-2-butanone and eucalyptol in grape fruit treated by phenylalanine are the most prominent; and the contents of hexyl acetate and beta-ionone in grape fruit treated by strigolactones are the most prominent.

[0010] The change of the type and content of aroma substances in grape fruits will not only change the aroma characteristics of the grape, make the aroma type of the grape fruits change, but also some specific volatile compounds can enhance the stress resistance, prolong the shelf life, etc. For example, the increase of the content of hexyl acetate will give fresh eating grape strawberry, apple and other fresh fruit aroma, which is beneficial to improve the palatability of the grape; and the beta-ionone is a carotenoid derivative, which contributes to the violet and woody tone, and improves the complexity of the aroma of the grape; the antioxidant property can also protect the stability of other volatile components; the terpenes and ester substances can inhibit the germination of mold spores, delay the release of ethylene, etc., so as to improve the stress resistance of the grape fruits and prolong the postharvest shelf life of the grape. According to the research results of the present application, methyl jasmonate can be sprayed on grape fruits to improve the stress resistance, postharvest preservation period and aroma of the grape; the treatment of the grape fruits by strigolactone can not only enhance the floral and fruity aroma of the grape fruits, enrich the aroma levels of the grape, so as to improve the quality and flavor of the fresh eating grape, but also can synergistically strengthen the stress resistance and nutritional quality of the grape fruits by the content-outstanding aroma components such as beta-ionone, nonanoic acid and octanoic acid.

[0011] Further, the exogenous plant growth regulator is strigolactone.

[0012] Further, the concentration of the strigolactone is 0.5-4 μmol / L.

[0013] On the other hand, the present application provides a method for regulating the aroma of grape fruits, which adopts the reagent according to any one of the above embodiments to treat the grape.

[0014] Since the content of the aroma components cannot be used as the basis for determining the aroma characteristics of the grape fruits, in order to clarify the contribution of the key aroma compounds in the grape fruits treated by the three kinds of exogenous plant growth regulators to the overall aroma of the fruits, the OAV of the different aroma components of the grape under different treatments is also studied in some embodiments of the present application. The results show that in the strigolactone treatment group, the main substances are decanal, ethyl heptanoate, beta-ionone, alpha-terpineol, nonanoic acid and geraniol, which make the floral and sweet aroma of the treated grape fruits more prominent. After the methyl jasmonate treatment, the prominent substances are n-hexanol, alpha-terpineol, geraniol, beta-damascone, nonanoic acid and octanoic acid, which make the grape fruits more have rose aroma, fruity aroma and sweet taste. Under the treatment of phenylalanine, the OAV values of n-hexanol, citronellol and decanal in the fruits are particularly prominent, which make the treated grape fruits more have floral aroma, rose aroma and grassy aroma.

[0015] Among them, alpha-terpineol and geraniol are synthesized in the biosynthesis pathway of monoterpenes, and are synthesized from geranyl pyrophosphate (GPP), a product of the upstream terpenoid skeleton synthesis pathway. Unlike beta-damascone, this substance is also generated from GPP, a product of the terpenoid skeleton synthesis, under the action of enzymes. Farnesol is further generated from neoxanthin under the action of carotenoid cleavage dioxygenase in the carotenoid synthesis pathway. After a series of enzymatic reactions, beta-damascone is finally formed. This substance has a very low threshold value and a high OAV value, and has a strong aroma proportion, and has a high contribution rate in the fruit aroma. In addition, nonanoic acid, octanoic acid and ethyl heptanoate are formed by fatty acid synthesis pathway and dehydrogenation, beta-oxidation of fatty acid synthesis pathway. Different is that ethyl heptanoate is formed in the aromatic compound degradation pathway under the action of alcohol acyltransferase (AAT). n-Hexanol is reduced from C6 aldehyde compound under the catalysis of lipoxygenase (LOX), and is an important source of green grass aroma of grape fruit.

[0016] Further, the method improves the aroma of grape fruit by increasing the content of any one or more of hexyl acetate, beta-ionone, octanoic acid, nonanoic acid, alpha-terpineol and geraniol in grape fruit.

[0017] In another aspect, the application provides the use of jasmolin for preparing a reagent for increasing the content of volatile flavoring substances of fruits to improve the aroma of fruits.

[0018] Further, the volatile flavoring substances include any one or more of hexyl acetate, beta-ionone, octanoic acid, nonanoic acid, alpha-terpineol and geraniol.

[0019] Further, the concentration of jasmolin is 0.5-4 μmol / L.

[0020] Further, the fruit is grape.

[0021] In another aspect, the application provides the use of jasmolin for preparing a reagent for changing the aroma type of grape fruit, and the concentration of jasmolin is 0.5-4 μmol / L.

[0022] The application has the following beneficial effects:

[0023] 1. By treating grape fruit with methyl jasmonate, phenylalanine and jasmolin, it is found that spraying these three plant growth regulators can significantly increase the content of organic compounds such as acids, esters and terpenes in grape fruit, thereby providing a theoretical basis for enriching the aroma characteristics of grape fruit, improving the stress resistance of grape fruit and prolonging the postharvest preservation period by exogenous plant hormone treatment.

[0024] 2. It was discovered that exogenous application of strigolactone can significantly alter the aroma of fresh Muscat grapes, increasing the content of substances such as hexyl acetate, β-ionone, caprylic acid, nonanoic acid, α-terpineol, and geraniol. This provides a new technical means for improving the aroma quality of aromatic grapes and offers a reference for subsequent research on the effects of strigolactone on fruit quality. Attached Figure Description

[0025] Figure 1 The figures show the OPLS-DA analysis and model cross-validation results for grape berries treated with different exogenous plant growth regulators. Figure A shows the OPLS-DA analysis results, with the horizontal axis representing predicted principal components and the vertical axis representing orthogonal principal components. Samples of the same color represent samples from the same treatment group. Figure B shows the model cross-validation results. The model quality assessment criteria include three indicators: R²X, R²Y, and Q². R²X and R²Y represent the model's explanatory power for the independent variable X and dependent variable Y, respectively. Q² is calculated through cross-validation and is used to evaluate the model's predictive ability. Generally, Q² > 0.5 is considered a valid model, and Q² > 0.9 indicates a very good model. The two dashed lines represent the threshold line of R² = 1 and the trend line of Q² changes, respectively.

[0026] Figure 2 Heatmaps showing the differences in aroma components in grapes treated with different exogenous plant growth regulators. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments. It should be noted that the embodiments described below are intended to facilitate understanding of the present invention and are not intended to limit it in any way. The reagents used in this embodiment are all known products and were obtained by purchasing commercially available products.

[0028] Example 1: Aroma Characteristics Analysis of Grape Fruits Treated with Exogenous Plant Growth Regulators

[0029] To investigate the aroma characteristics of 'Hanxiangmi' grapes after treatment with different exogenous plant growth regulators, volatile components were extracted from grape samples treated with three different exogenous plant growth regulators using SH-SPME and analyzed by GC-MS. The specific methods are as follows:

[0030] I. Experimental Materials

[0031] In May 2024, five-year-old 'Hanxiangmi' grapevines with good growth and consistent growth were selected at Dicuiyuan Farm in Zhenhai District, Ningbo City (121°32′E, 29°59′N) for treatment with exogenous plant growth regulators.

[0032] II. Handling Methods

[0033] The exogenous plant growth regulators methyl jasmonate (purchased from Solabia, model IM5630), strigolactone (purchased from Solabia, model SS5720), strigolactone inhibitor (purchased from Solabia, model IT1220) and phenylalanine (purchased from Solabia, model P0010) were used to treat the fruit at the turning color stage. Each treatment had 3 plants, and each plant had at least 5 clusters of fruit. After the fruit ripened, it was collected, stored at low temperature, transported to the laboratory, and stored in a -80°C freezer. The treatment method is shown in Table 1. The solution was uniformly sprayed on the whole cluster of fruit using a sprayer until the surface droplets reached the critical state and began to flow steadily. In the analysis of the test results, M1500 and M2000 represent 1500 μmol / L and 2000 μmol / L methyl jasmonate treatment, respectively, G0.5, G1, G2, and G4 represent 0.5 μmol / L, 1.0 μmol / L, 2.0 μmol / L, and 4.0 μmol / L strigolactone treatment, respectively, T1 represents 1.0 μmol / L strigolactone inhibitor treatment, and P60 and P140 represent 60 mg / L and 140 mg / L phenylalanine treatment, respectively.

[0034] Table 1. Experimental treatment concentration and treatment method

[0035]

[0036] III. GC-MS determination

[0037] For the 'Hanxiangmi' grape samples sprayed with the three different exogenous plant growth regulators, 60 g of each was ground and centrifuged to obtain transparent juice. The grape juice was transferred to a 20 mL Agilent bottle (Agilent Technologies, Santa Clara, USA) equipped with a magnetic stirrer and 1.5 g of NaCl, 2-octanol was used as an internal standard, and the sample bottle was sealed with a cap equipped with a silica gel top. By the HS-SPME method, after the sample bottle was equilibrated at 50°C for 10 minutes, the solid phase microextraction head (solid phase microextraction fiber, 50 / 30 μM DVB / CAR / PDMS, Supelco, Bellfonte, USA) was inserted and the volatile aromatic compounds were extracted at 50°C for 30 minutes, then inserted into the injection port of the chromatograph (Agilent 8890 GC, Agilent Technologies) and desorbed at 260°C for 3 minutes without separation mode and equipped with a 5977 mass selective detector (Agilent Technologies). Each treatment was repeated three times, and the average value was taken.

[0038] The GC conditions are as follows: an HP-INNOWAX chromatographic column (30 mm x 0.25 mm x 0.25 μm; Agilent Technology) is used; the carrier gas is 99.99 % helium, and the flow rate is 1 mL / min; the column temperature is kept at 40 °C for 5 minutes, then increased to 240 °C at a rate of 5 °C / min, and then increased to 260 °C at a rate of 20 °C / min and kept for 5 minutes.

[0039] The MS conditions are as follows: the mass transfer line temperature and ionization source temperature are 260 °C and 230 °C, respectively; the electron impact mass spectrometer data in the range of 20-400 m / z are collected at an ionization voltage of 70 eV.

[0040] IV. Data processing

[0041] The GC-MS results are as follows: the mass spectrometry of the volatile compounds of the sample is qualitatively analyzed according to the NIST / EPA / NIH mass spectrum library (NIST2014) database; the content of the aroma components is quantitatively analyzed by comparing the peak area with the internal standard, and the unit is μg / g, that is, the content of the aroma components = aroma component substance peak area x internal standard content / internal standard peak area. The data are summarized and arranged by using office, and the average value and standard deviation are calculated;

[0042] The heat map is drawn by using TBtools. The principal component analysis (PCA) results are extracted and visualized by using SIMCA 14.1, and the orthogonal partial least squares-discriminant analysis (OPLS-DA) is calculated, and the variable importance in projection (VIP) is calculated. The picture is processed by using Adobe Illustrator 2022.

[0043] V. Analysis of aroma characteristics

[0044] As can be seen from Table 2, 39 common effective volatile aroma substances are detected in the jimsonweed lactone (SL) treatment group, and the contents of acid, alcohol, aldehyde, ester and monoterpene substances are increased compared with the CK group. In the SL and its inhibitor treatment groups, the above-mentioned several types of compounds are up-regulated to different degrees. Among them, the changes of substances in the G2, G4 and T1 treatment groups are particularly significant, indicating that SL may have a strong induction effect on the regulation of grape fruit aroma synthesis. Especially in the accumulation of ester and terpene substances, the SL treatment appears to be significantly improved, which is speculated to be able to enhance the activity of related metabolic pathways by regulating the interaction between carbon flow distribution and signal pathways (such as interaction with JA, ABA and other hormones), thereby promoting the synthesis of aroma substances.

[0045] As shown in Table 3, in the methyl jasmonate (MeJA) treatment group, 48 common effective aroma substances were detected, which was the most in the three groups, including 6 acids, 3 alcohols, 7 aldehydes, 9 esters, 6 ketones and 15 terpenes. Compared with the CK group, MeJA treatment significantly increased the overall content of VOCs in grape fruits, especially in aldehydes, acids, esters and terpenes. This shows that MeJA as a signal molecule has a wide and strong regulatory effect on the induction of plant secondary metabolism. It is worth noting that representative terpene aromatic substances such as geraniol, nerol and orange ether were not detected in the CK control group, but accumulated significantly in the MeJA treatment group, which is speculated to be involved in aroma synthesis by activating the expression of key enzyme genes (such as GPPS, TPS, etc.) in the terpene synthesis pathway (such as MVA, MEP pathway). In addition, the significant increase in terpenes may also be related to the increased activity of transcription factors (such as MYC2) induced by MeJA, further driving the reprogramming of terpene secondary metabolic networks.

[0046] In the phenylalanine (Phe) treatment group, 36 common effective aroma substances were detected, covering 6 main volatile compounds, including 6 acids, 2 alcohols, 5 aldehydes, 10 esters, 6 ketones and 11 terpenes. Compared with the CK group, Phe treatment significantly changed the content of some aroma components. Among them, acetic acid, an acid, was not detected in the treatment group, indicating that it may be inhibited or consumed by transformation. In aldehydes, the content of nonanal increased significantly, which is speculated to be related to the enhanced fatty acid beta-oxidation. Ester and ketone compounds generally showed an upward trend, indicating that Phe may promote esterification and secondary metabolite synthesis in fruits by regulating intermediate metabolic pathways. However, the overall content of terpenes did not change significantly, indicating that Phe has weak regulatory effect on the terpene synthesis pathway.

[0047] Table 2 Aroma substances of grape fruits after brassinolide treatment

[0048]

[0049]

[0050] Table 3 Aroma substances of grape fruits after methyl jasmonate and phenylalanine treatment

[0051]

[0052]

[0053] In summary, three kinds of exogenous plant growth regulators all affected the composition and content of volatile aroma substances in the fruit of 'Hanhxiangmi' grape in different degrees. Among them, MeJA treatment had the most significant effect on the type and content of aroma substances in the fruit, especially the significant accumulation of terpenes, which might have important contributions to the enhancement of floral and fruity characteristics; Phe treatment group mainly promoted the synthesis of esters, ketones and other fatty acid derivatives, while the effect on terpenes was small; SL treatment showed a synergistic increase in various types of aroma substances, which might affect the aroma metabolic network through synergistic regulation mechanism with multiple hormone pathways.

[0054] Example 2: Analysis of aroma component differences

[0055] In order to further analyze the effect of three kinds of exogenous plant growth regulators on fruit aroma substances in this experiment, the common aroma components of different plant exogenous growth regulators were used as dependent variables, and different treatment concentrations were used as independent variables. The OPLS-DA (Orthogonal Partial Least Squares Discriminant Analysis) model can realize the effective differentiation of grape samples treated by three kinds of exogenous plant growth regulators. Figure 1 The fitting index of independent variable in this analysis was 0.948 (R 2 x), the fitting index of dependent variable was 0.999 (R 2 y), the model prediction index was 0.798 (Q 2 ), R 2 and Q 2 more than 0.5 means that the model fitting result is acceptable. After 200 times of permutation test, as shown in B of Figure 1 , it is proved that there is no overfitting in the model, the model validation is effective, and the result can be used for the differential analysis of grape aroma in this experiment.

[0056] The types of aroma components of grape samples in three treatment groups were similar, but the total content of each type of substance was different. The highest content of aroma components was acid, followed by ester and terpene. The content of ester compounds in methyl jasmonate and phenylalanine treatment groups was significantly higher than that in the tributyrin treatment group, while the content of acid substances in the tributyrin treatment group was significantly higher than that in the other two treatment groups.

[0057] In order to further analyze the contribution rate of different aroma components in fruit treated by different exogenous plant growth regulators, according to the data analysis structure of this example, 17 kinds of differential aroma substances were screened out according to the standard of P<0.05 and VIP>1. Figure 2), among which there were 1 alcohol, 3 acids, 2 esters, 2 aldehydes, 3 ketones and 6 terpenes. From the heat map, it can be seen that the most prominent components in the control group were 7, namely valeric anhydride, citronellol, decanal, n-hexanol, isophthalaldehyde, acetic acid and 3-hydroxy-2-butanone; the most prominent components in the methyl jasmonate treatment group were 10, namely nerol, n-hexanol, geraniol, hexyl acetate, octanoic acid, beta-damascone, acetic acid, ethyl heptanoate, citronellol and isophthalaldehyde. The most prominent components in the strigolactone treatment group were 7, namely hexyl acetate, beta-ionone, octanoic acid, nonanoic acid, acetic acid, geraniol and alpha-terpineol. The most prominent components in the phenylalanine treatment group were 6, namely ethyl heptanoate, 3-hydroxy-2-butanone, eucalyptol, alpha-terpineol, isophthalaldehyde and beta-ionone.

[0058] From the above results, it can be found that the contents of nerol, n-hexanol and beta-damascone in the methyl jasmonate treatment group were significantly higher than those in other groups, enhancing the intensity of rose fragrance; in the strigolactone treatment group, the contents of hexyl acetate, beta-ionone and nonanoic acid were significantly higher than those in other groups. Among them, according to the characteristics of hexyl acetate, beta-ionone and nonanoic acid, hexyl acetate and nonanoic acid can inhibit the germination of mold spores, thereby improving the disease resistance of the fruit, and at the same time, hexyl acetate also has a sweet fruit aroma. Beta-ionone belongs to C13-norisoprenoids, has violet and woody aroma, and its increased content can improve the complexity of the aroma of 'Hanxiangmi'. In addition, the antioxidant property of beta-ionone can also reduce the oxidative damage of grape fruit. Strigolactone treatment increases the complexity of the aroma type of grape fruit, making rose grape change into a mixed aroma type of floral, grassy and fruity, with rich layers of aroma. The effect of phenylalanine is not obvious. In summary, according to production needs, strigolactone will be used for fresh table grapes, wine grapes and grape stress management, which will significantly improve the flavor and quality of grapes.

[0059] Example 3: OAV analysis of different aromas

[0060] Odor activity value (OAV) can determine the ratio of the concentration of a single volatile to its odor threshold in water or air, and can study the contribution of potential key aroma compounds in grape fruit to the overall aroma of the fruit. The content of aroma components cannot be used as a basis for determining the aroma characteristics of grape fruit, and usually the aroma components with high OAV give the grape aroma characteristics. Previous studies have evaluated the contribution of individual aroma to the overall aroma of grape fruit by calculating OAV. When OAV is greater than 1, it is considered that the aroma component has a certain influence on the aroma of grape fruit, and when OAV is greater than 10, it is considered that the aroma component has a great contribution to the overall aroma of grape fruit.

[0061] The aroma component threshold value and aroma description according to the literature report and sorting are shown in Table 4. At the same time, the advantage group is further screened according to the aroma difference analysis of the experimental groups, and the OAV of the different aroma components of the grape fruit under the treatment of different exogenous plant growth regulators is calculated.

[0062] Table 4 Threshold value and aroma description of different aroma components of grape fruit

[0063]

[0064] Table 5 OAV of different aroma components of grape fruit under different treatments

[0065]

[0066] The results show (Table 5) that the OAV values of nonanoic acid, geraniol and a-pinene alcohol in the striga lactone treatment group (G0.5, G1, G2 and G4) are greater than 1 and significantly increased, indicating that the above substances may be the key components of striga lactone affecting fruit aroma. Among them, the octanoic acid in G2 group is greater than 1 and significantly increased; the decanal, ethyl heptanoate, beta-damascenone and eucalyptol in G0.5, G1 and G4 groups are greater than 30 and significantly increased; the beta-ionone in G1 and G4 groups is greater than 450 and significantly increased. It shows that different concentrations of striga lactone affect the fruit aroma components and have specificity. In the methyl jasmonate treatment group (M1500 and M2000), the OAV values of nonanoic acid, octanoic acid, n-hexanol, beta-damascenone, geraniol and a-pinene alcohol are greater than 1 and significantly increased; the decanal is less than 1 and significantly decreased; it shows that the above substances may be the key components of methyl jasmonate affecting fruit aroma. In addition, there is no obvious specificity in different concentration treatment. In the phenylalanine treatment group (P60 and P140), the OAV values of nonanoic acid and a-pinene alcohol are greater than 1 and significantly increased; the citronellol is less than 1 and significantly decreased; it shows that the above substances may be the key components of phenylalanine affecting fruit aroma. The OAV values of the rest of the substances are small and have no obvious difference with CK.

[0067] Compared with the control group, the OAV of decanal, ethyl heptanoate, beta-ionone, beta-damascone, alpha-terpineol, nonanoic acid and geraniol in the jussiaea insulata lactone treatment group was significantly prominent, with floral and fruity characteristics, and among them, such as ethyl heptanoate, beta-ionone, beta-damascone, the OAV was significantly higher than 10, indicating that these substances contributed more significantly to the aroma characteristics of the grape; the OAV of n-hexanol, alpha-terpineol, geraniol, beta-damascone, nonanoic acid and octanoic acid in the methyl jasmonate treatment group was relatively prominent, and the OAV of n-hexanol and alpha-terpineol was more prominent, indicating that these two substances played a more significant role in giving the grape floral and grassy aroma; in the phenylalanine treatment group, the OAV of alpha-terpineol and nonanoic acid was relatively prominent, with floral and grassy aroma. According to the above results, it can be concluded that the exogenous hormone treatment of grape with jussiaea insulata lactone not only can realize the regulation and transformation of the aroma of grape fruit, but also can give the grape more rich and more hierarchical aroma characteristics, and the effect is better than that of phenylalanine and methyl jasmonate, and the effect of treating grape fruit with 4.0 μmol / L jussiaea insulata lactone is more significant. Therefore, in actual production application, jussiaea insulata lactone can be used to treat grape fruit to meet the needs of different consumer groups for fresh grape or wine grape.

[0068] In addition, in order to verify the feasibility of jussiaea insulata lactone in regulating the aroma characteristics of grape fruit, the present application further takes another 6 'Hanxiangmi' grapes from the same source as experimental materials for verification, and the grape treatment method, aroma substance determination and analysis are the same as in Example 1, and the OAV values of different aroma substances in different treatment groups are analyzed. The results show that, consistent with the above results, the OAV values of decanal, ethyl heptanoate, beta-ionone, beta-damascone, alpha-terpineol and nonanoic acid in the jussiaea insulata lactone treatment group are significantly prominent, giving the grape fruit floral, grassy and fruity aroma; the OAV of n-hexanol and alpha-terpineol in the methyl jasmonate treatment group is more prominent, giving the grape fruit floral and grassy aroma; in the phenylalanine treatment group, the OAV value of alpha-terpineol is relatively prominent, but the effect is not obvious, which proves that the aroma characteristics of grape fruit treated by different exogenous plant growth regulators have obvious differences, and the aroma of grape fruit treated by jussiaea insulata lactone is more rich in levels.

[0069] The above results again prove that there are significant differences in the aroma transformation of grape fruit treated by methyl jasmonate, jussiaea insulata lactone and phenylalanine: the treatment effect of phenylalanine is not obvious, methyl jasmonate enhances the floral intensity of 'Hanxiangmi' grape; jussiaea insulata lactone gives the grape beta-ionone, nonanoic acid and other characteristic aroma substances, so that the treated grape has floral, fruity and grassy aroma, the aroma type is more complex, and the level is more rich, which has a significant advantage compared with the other two regulators.

[0070] Example 4: Comparison of the effect difference of different treatment methods

[0071] In order to explore whether the aroma substances and their contribution to the overall aroma of the fruit will be significantly different when the same exogenous plant growth regulator is sprayed on the grape fruit by different treatment methods, the effects of spraying 'Hanxiangmi' grape by spraying the fruit cluster or inflorescence or leaf as shown in Table 6 were also compared. The aroma substance determination, analysis and OAV value analysis method of the grape fruit after different treatments were the same as in Example 1-3, and the experimental material source was the same as in Example 1. The OAV value analysis results of 'Hanxiangmi' grape after different treatments are shown in Tables 7-9.

[0072] Table 6 Experimental treatment concentration and treatment method

[0073]

[0074] Table 7 OAV of different aroma components of grape fruit after spraying exogenous plant growth regulator on fruit cluster

[0075]

[0076] Table 8 OAV of different aroma components of grape fruit after spraying exogenous plant growth regulator on inflorescence

[0077]

[0078] Table 9 OAV of different aroma components of grape fruit after spraying exogenous plant growth regulator on leaf

[0079]

[0080] From the results of Tables 7-9, it can be found that there are significant differences in the OAV values of aroma substances measured from grape fruit when the same exogenous plant growth regulator is sprayed on the fruit cluster, inflorescence and leaf of grape. The OAV values of different aroma substances in grape fruit after spraying on inflorescence or leaf are lower than those in grape fruit after spraying on fruit cluster. Taking kudouzhi lactone as an example, the OAV value of acetic acid is reduced to 0, the OAV value of a-pinene is reduced to less than 10, and the OAV of heptanoic acid ethyl ester, β-ionone and other aroma substances with significantly outstanding OAV are also significantly reduced compared with the OAV of grape fruit after spraying on fruit cluster, indicating that the treatment method of spraying on fruit cluster is the most effective in improving the aroma characteristics of fruit.

[0081] Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should belong to the scope of protection of the present application.

Claims

1. Use of solavetivone for the preparation of an agent for converting a grape from a Muscat type to a mixed floral, grassy and fruity type by increasing the olfactory activity values of the volatile aroma substances of the grape berries, characterized in that, The volatile flavor substances are composed of decanal, ethyl heptanoate, beta-ionone, beta-damascenone, alpha-terpineol, nonanoic acid and geraniol, the concentration of the strigolactone is 0.5-4 μmol / L, and the variety of the grape is Hanxiangmi.

2. Use of a strigolactone for the preparation of an agent for modifying the aroma of grape berries by increasing the olfactory activity values of the volatile aroma substances of the grape berries, characterized in that, The volatile flavor substances are composed of decanal, ethyl heptanoate, beta-ionone, beta-damascenone, alpha-terpineol, nonanoic acid and geraniol.

3. An agent for changing the flavor of grape fruits by increasing the odor active value of volatile flavoring substances of grape fruits, characterized by, The reagent is strigolactone, and the concentration of the strigolactone is 0.5-4 μmol / L.

4. A method for modifying the aroma profile of grape berries, characterized in that, The grape is treated by strigolactone, and the concentration of the strigolactone is 0.5-4 μmol / L.

5. The method of claim 4, wherein, The grape fruit aroma type is changed by improving the odor activity value of decanal, ethyl heptanoate, beta-ionone, beta-damascenone, alpha-terpineol, nonanoic acid and geraniol in grape fruit.

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