NL2030095B1 - Method for improving melatonin and aroma of wine grape fruits by utilizing l-tryptophan - Google Patents

Abstract

Disclosed is a method for improving melatonin and aroma of wine grape fruits by utilizing L- tryptophan. The method specifically includes: applying the L-tryptophan during veraison of grape fruits. The present invention can increase content of aroma substances and melatonin in the grape fruits to achieve more intensive flavour and higher melatonin content, and has important effects of increasing nutrition and health care values of the grapes, producing high-end wine and increasing planting benefits.

Description

METHOD FOR IMPROVING MELATONIN AND AROMA OF WINE GRAPE FRUITS BY UTILIZING L-TRYPTOPHAN Technical Field The present invention relates to the technical field of grape planting, and particularly relates to a method for improving melatonin and aroma of wine grape fruits by utilizing L-tryptophan.

Background Marselan, a wine grape variety, is introduced from France, is derived from hybridization of “Cabernet Sauvignon” and “Grenache Noir”, and is a Eurasian hybrid variety.

The Marselan is blue-black in peel, large in cluster, conical, slightly loose, small in grain and strong in fruity flavour and mint scent of fruits, and ripens in mid-to-late September.

Due to wide planting adaptability and high wine quality, the Marselan has wide development prospects.

At present, the variety Marselan is planted in five major producing areas in China, i.e., Xinjiang, Ningxia, Hebei, Shanxi and Shandong; and a planting area of the variety is continuously enlarged.

When affected by regional climate differences, the Marselan grape has a phenomenon of insufficient fruit aroma accumulation.

Under the circumstance, the fruit flavour may be effectively improved by increasing aroma content; and wine flavour may be indirectly improved.

Melatonin is a strong bioactive substance.

Researches show that, through in-vitro supplement of the melatonin, a melatonin level in the body may be maintained in a young state, thereby adjusting and recovering circadian rhythms, enhancing deep sleep and improving sleep quality.

The melatonin has effects of regulating cellular immunity and humoral immunity, regulating activities of multiple cytokines, regulating the human cardiovascular system, the respiratory system, the digestive system and the urinary system, improving a function state of the whole body, improving life quality and delaying the aging process.

Based on this, as a nutrition and health care substance, the melatonin increases values of the grapes and indirectly increases nutrition and health care values and other functional values of the wine.

Under a condition that soil, water and fertilizer are managed properly, content of aroma substances and melatonin in fruits is increased to achieve more intensive flavour and higher melatonin content on premise of ensuring basic quality indexes.

The melatonin has important effects of increasing nutrition and health care values of the grapes, producing high-end wine and increasing planting benefits.

However, at present, there is no method for effectively improving aroma substances and melatonin accumulation in Marselan grape fruits.

L-tryptophan, also called a-aminoindolyl propionic acid, is synthesized from indolal, may serve as a dietary supplement or an antioxidant, and may also be applied to medicines for regulating mental rhythms and improving sleep.

Researches show that, in plants, as a precursor for melatonin synthesis, the L-tryptophan can participate in endogenous melatonin synthesis in the plants.

In biosynthesis of aroma substance of the plants, an amino acid pathway serving as an important synthesis pathway plays an important role. Researches show that, application of L- tryptophan fertilizers in the plants can increase nutrient absorption capacity of crops, improve quality and yield of the crops including cabbage, watermelon and muskmelon, and can also promote growth of corn. However, there is no research and discussion on the effects of application of the L-tryptophan on the melatonin and aroma substances in the crops.

Summary In view of this, the present invention provides a method for improving melatonin and aroma of wine grape fruits by utilizing L-tryptophan.

To achieve the above purpose, technical solutions of the present invention are as follows: The method for improving melatonin and aroma of wine grape fruits by utilizing L-tryptophan includes: applying the L-tryptophan during veraison of grape fruits.

The above technical solution has beneficial effects as follows: the grape fruits are the most sensitive to exogenous signals before veraison; and the application of the L-tryptophan has the best treatment effect during the period. The L-tryptophan is a precursor for synthesis of the melatonin and aroma substances and may be metabolically transformed into melatonin and aroma. In addition, the melatonin serving as a signal substance may improve aroma synthesis. The L-tryptophan may promote aroma synthesis by increasing the melatonin.

Preferably, an application concentration of the L-tryptophan is 200-300 mg/L; the L- tryptophan is totally applied once in a root drip irrigation manner, and an average application amount of each plant is 15-25 L; or the L-tryptophan is subjected to foliage spray once, and an average application amount of each plant is 0.3-0.7 L.

The above technical solution has beneficial effects as follows: the increase of the use frequency or increase of the application amount will decrease the improvement amplitude of the melatonin and the aroma, and use cost is increased; and moreover, if the application amount is decreased, the treatment effect is significantly decreased.

Preferably, the L-tryptophan is applied when soluble solid content in the grape fruits is up to

12.0+0.5. The above technical solution has beneficial effects as follows: when the soluble solid content is up to 12.0+0.5, it is indicated that the grape fruits enter an initial ripening stage. The stage is the most sensitive to nutrition and signal substances and is theoretically an optimum period of exogenous regulation.

Preferably, after the application of the L-tryptophan, fruits and a tree body are regularly managed, without special requirements.

Through the above technical solutions, compared with the prior art, the present invention has beneficial effects as follows: current amino acid fertilizers are mainly used for improving leaf quality, tree growth and saccharic acid content in fruits; there is no technical solution for increasing the melatonin and aroma substances in the grape fruits; the technical solution for improving melatonin and aroma of grape fruits by utilizing L-tryptophan is established first in the present invention; and compared with those in treatments with water and glycine, the total amount of the melatonin and aroma can be respectively increased by 1.31 times and 3.71 times or more.

Description of Drawings To more clearly describe the technical solution in the embodiments of the present invention or in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be simply presented below.

Apparently, the drawings in the following description are merely the embodiments of the present invention, and for those ordinary skilled in the art, other drawings can also be obtained according to the provided drawings without contributing creative labour.

Fig. 1 shows effects of different treatment agents on content of aroma substances in fruits; Fig. 2 shows effects of different treatment agents on melatonin content of fruits; Fig. 3 shows effects of L-tryptophan treatments of different concentrations on aroma content of fruits; Fig. 4 shows effects of L-tryptophan treatments of different concentrations on melatonin content of fruits; Fig. 5 shows effects of different L-tryptophan application manners on aroma content of fruits; Fig. 6 shows effects of different L-tryptophan application manners on melatonin content of fruits; Fig. 7 shows effects of different L-tryptophan treatment times on aroma content of fruits; Fig. 8 shows effects of different L-tryptophan treatment times on melatonin content of fruits; Fig. 9 shows effects of different L-tryptophan treatment stages on aroma content of fruits; and Fig. 10 shows effects of different L-tryptophan treatment stages on melatonin content of fruits.

Detailed Description The technical solution in embodiments of the present invention will be clearly and fully described below.

Apparently, the described embodiments are merely part of the embodiments of the present invention, not all of the embodiments.

Based on the embodiments in the present invention, all other embodiments obtained by those ordinary skilled in the art without contributing creative labour will belong to the protection scope of the present invention.

Embodiment 1 A method for improving melatonin and aroma of wine grape fruits by utilizing L-tryptophan Treated grape variety: Marselan Grape planting mode: a conventional planting mode, having a row spacing of 80 cm and a line spacing of 2 m.

Treatment reagent: L-Tryptophan, having a molecular formula of C11H2N202, a molecular weight of 204.2252 and purity of 295%, and purchased by order online: https://www.aladdin- e.com/zh_cn/. Treatment concentrations and times: application concentrations of 50 mg/L, 250 mg/L and 500 mg/L; totally applied for 1-3 times; applied within 15 days before veraison, during veraison and within 15 days after veraison, wherein the grape fruits are the most sensitive to exogenous signals during veraison, and the time period has the best treatment effect theoretically. Treatment manner and dose: applied in a root drip irrigation manner or in a foliar spray manner; an average application amount of each plant is 20 L during drip irrigation; after application of the L-tryptophan, a soil layer of 40 cm deep can be fully wetted; and the foliar spray is sufficient when the leaf surface is wet, and the dose is up to about 0.5 L. Fruit and tree body management manner after treatment: conventional management, without special requirements. Control: a treatment reagent is water. Test results

1. Effect comparison of different treatment agents (drip irrigation, an average application amount of 20 L for each plant, applied once, and applied during the fruit veraison) Effects of treatments of three treatment agents (250 mg/L of L-tryptophan, 250 mg/L of glycine and water) on aroma and melatonin in fruits are evaluated. The results show that, through Table 1, compared with the control (drip irrigation by the same amount of water), the application of the L-tryptophan increases the melatonin content in fruits by 1.46 times compared with that in the water treatment, and increases the melatonin content by 1.31 times compared with that in the glycine treatment. It can be seen from Table 2 that, after the application of the L-tryptophan, total content of aroma substances in the fruits is 4.13 times that of the content in the water control, and is 3.71 times that of the content in the glycine treatment. For characteristic aroma substances of Marselan grapes, the total content is 4.09 times that of the content in the water control, and 2 varieties of the aroma substances are increased. The characteristic aroma substance with the highest content is (E)-2-hexenal. In addition, the L-tryptophan treatment further increases content of alcohols, aldehydes and other types of aroma substances in the fruits. Total content of the alcohols is respectively increased by 13.98% and 12.53% compared with that in the water control and the glycine treatment. Total content of the aldehydes is respectively increased by 5.08 times and 3.05 times compared with that in the water control and the glycine treatment. Total content of the other aroma substances is respectively increased by 1.71 times and 0.88 time compared with that in the water control and the glycine treatment.

Table 1 Effects of L-tryptophan treatment on content of aroma substances and melatonin in fruits (unit: ng/g FW) ~~ tem ~~ Water ~~ Ltryptophan = Glycine Characteristic aroma ~~ 151650 ~~ 619.93a ~~ 15554b Alcohols 24.32a 25.35a 22.48a Aldehydes 132.21b 671.57a 140.65b Other aroma 4.51b 7.71a 5.23b Total aroma content 312.69¢ 1324.56a 356.57b Melatonin 3.55b 8.73a 3.78b Notes: data in the table are mean values of three repeats; and different letters represent no 5 significant difference on 5% level.

Table 2 Effects of L-tryptophan treatment on content of aroma substances in fruits (unit: ng/g FW) ~~ Englishname ~~ Water Ltryptophan = Glycine ~~ Characteristic aroma ~~ B-cyclocitral 0.88b 1.22a 0.92b linalool 0.71a 0.00c 0.57b y-cadinene 0.69 0.00 0.71 theaspirane 0.55b 1.84a 0.32c zonarene 0 0.39 0 dinydroedulan 0.15b 0.314 0.05¢c citral 0 0.00 0.05 (E)-2-nonenal 0 0.83 0 (E)-2-octenal 0 1.93 0 (E)-2-hexenal 144.29b 596.48a 153.62b Geraniol 2.14b 5.17a 2.01b Geranial 0 0.92 0.33 B-ionone 2.24c 10.844 5.02b ~~ Alcohols (E)-2-hexenol 2.07b 1.80c 2.574 1-hexanol 16.59a 12.38C 14.36b 1-octanol 0.81b 1.43a 0.58c 1-nonanol 0 0.32 0 1-penten-3-ol 0.15 0.00 0.14 1-octen-3-ol 1.10b 1.73a 0.85¢ 3-methyl-1-butanol 0.56 0.00 0.60 2-ethyl-1hexanol 0.72b 2.49a 0.76b benzyl alcohol 0.64b 2.94a 0.75b phenylethyl alcohol 1.68b 2.464 2.354

Aldehydes Butanal 0 0.99 0.14 pentanal 1.98 0.00 1.02 hexanal 117.22b 636.10a 150.32b heptanal 0 0.70 0.12 octanal 3.37b 5.16a 2.15¢ nonanal 2.950C 10.464 3.98b decanal 2.20b 6.204 2.44b benzaldehyde 0.90c 3.15a 1.65b benzeneacetaldehyde 1.72¢ 4.63a 2.36b 2-methyl butanal 0.66a 0.53a 0.54a 3-methyl butanal 1.21a 1.37a 1.18a (E,Z)-2,8-nonadienal 0 2.28 0 ~~ otheraroma o-xylene 0.29 0.00 0.05 p-xylene 0.28 0.00 0.14 ethylbenzene 0 0.56 0 diethyl phthalate 0.63 0.00 0 methyl salicylate 2.64b 7.15a 3.02b 3,5-bis(1,1-dimethylethyl)-phenol 0.29 0.00 0.61 Cyclooctatetraene 0.27 0.00 0.29 hexanoic acid 0.11 0.00 0 Total amount ofthe aroma substances ~~ 312.69b ~~ 1324.56a OO 356.57b © Notes: data in the table are mean values of three repeats; and different letters represent ~~ no significant difference on 5% level.

2. Effect comparison of different L-tryptophan treatment concentrations (drip irrigation, an average application amount of 20 L for each plant, applied once, and applied during the fruit veraison) As shown in Table 3, effects of treatments of three L-tryptophan concentrations (50 mg/L, 250 mg/L and 500 mg/L) on aroma and melatonin in fruits are evaluated. The results show that, the treatments of the three concentrations significantly increase the characteristic aroma, the aldehyde aroma substances, the other aroma substances and the total aroma content in the fruits. For the characteristic aroma, the aldehyde aroma and the total aroma content, the effect of the treatment of 250 mg/L is optimum and is 4.09 times, 5.08 times and 4.24 times that of the control; there is no significant difference between the treatment of 50 mg/L and the treatment of 500 mg/L, and effects of both the treatment of 50 mg/L and the treatment of 500 mg/L are significantly higher than that of the control, but are inferior to that of the treatment of 250 mg/L. For the melatonin, the effect of the treatment of 250 mg/L is optimum and is 2.46 times that of the control; and effects of the treatment of 50 mg/L and the treatment of 500 mg/L are lower than that of the control. The above contrast tests show that, the treatment of 250 mg/L has the optimum effect. Table 3 Effects of L-tryptophan treatments of different concentrations on content of aroma and melatonin in fruits (unit: ng/g FW) ~~ Item ~~ Control ~~ 50mg/L 250mg ~~ 500mglL © Characteristic 151.65¢c ~~ 45497b ~~ 619.93a ~~ 459.97b aroma Alcohols 24 32a 18.42b 25.35a 15.32b Aldehydes 132.21C 537.8b 671.57a 532.63b Other aroma 4.51c 5.35b 7.71a 8.74a Total aroma content 312.69c 1016.54ab 1324 .56a 1016.66ab Melatonin 3.55b 3.40b 8.73a 2.85¢c Notes: data in the table are mean values of three repeats; and different letters represent no significant difference on 5% level.

3. Effect comparison of different L-tryptophan application manners (drip irrigation and foliar spray) Drip irrigation parameters: the L-tryptophan treatment concentration is 250 mg/L; an average application amount for each plant is about 20 L; the L-tryptophan is applied once; and application time is fruit veraison.

Foliar spray parameters: the L-tryptophan treatment concentration is 250 mg/L; an average application amount for each plant is about 0.5 L; the L-tryptophan is applied once; and application time is fruit veraison.

As shown in Fig. 4, effects of two L-tryptophan application manners (root application and foliar spray) on aroma and melatonin in fruits are evaluated. The results show that, both the two application manners significantly increase the characteristic aroma, the aldehyde aroma substances, the other aroma substances, the total aroma content and the melatonin content in the fruits. For the characteristic aroma, the aldehyde aroma and the total aroma content, the root application treatment has the optimum effect; effects of foliar spray treatments are all significantly higher than that of the control, but are inferior to the effect of the root application treatment. For the melatonin, the root application treatment has the optimum effect; effects of the foliar spray treatments are significantly higher than that of the control but lower than the effect of the root application treatment, while the difference is not significant. The above contrast tests show that, the root application treatment has the optimum effect.

Table 4 Effects of different L-tryptophan application manners on content of aroma and melatonin in fruits (unit: ng/g FW) tem Control Foliarspray Root application "Characteristic aroma 151.65¢ ________ 371430 6819.93a Alcohols 24 32a 15.82b 25.35a Aldehydes 132.21¢ 413.95b 671.57a Other aroma 4.51c 9.154 7.71b Total aroma content 312.69¢ 810.34b 1324 .56a Melatonin 3.55b 7.06a 8.73a Notes: data in the table are mean values of three repeats; and different letters represent no significant difference on 5% level.

4. Effect comparison of different L-tryptophan treatment times Parameters of the application once: the L-tryptophan treatment concentration is 250 mg/L; an average application amount for each plant is about 20 L; the L-tryptophan is applied once; and application time is fruit veraison.

Parameters of the application twice: the L-tryptophan treatment concentration is 250 mg/L; an average application amount for each plant is about 20 L; the L-tryptophan is applied twice; and application time is within 15 days before fruit veraison and during veraison.

Parameters of the application for three times: the L-tryptophan treatment concentration is 250 mg/L; an average application amount for each plant is about 20 L; the L-tryptophan is applied for three times; and application time is within 15 days before fruit veraison, during veraison and within 15 days after veraison.

As shown in Fig. 5, effects of three kinds of L-tryptophan treatment times (such as once, twice and 3 times) on aroma and melatonin in fruits are evaluated. The results show that, the three different kinds of treatment times significantly increase the characteristic aroma, the alcohol aroma substances, the aldehyde aroma substances, the other aroma substances and the total aroma content in the fruits. For the characteristic aroma, the aldehyde aroma and the total aroma content, the L-tryptophan treatment once has the optimum effect; effects of the L-tryptophan treatment twice and the L-tryptophan treatment of 3 times are significantly higher than that of the control, but are inferior to that of the L-tryptophan treatment once. For the melatonin, the L- tryptophan treatment once has the optimum effect; effects of the L-tryptophan treatment twice and the L-tryptophan treatment of 3 times are significantly higher than that of the control, but are inferior to that of the L-tryptophan treatment once. The above contrast tests show that, the L- tryptophan treatment once has the optimum effect.

Table 5 Effects of different L-tryptophan treatment times on content of aroma and melatonin in fruits (unit: ng/g FW) ~~ item Control = Once Twice 3times “Characteristic aroma ~~ 151.65c ~~ 619.93a ~~ 440.08b ~~ 400.31b © Alcohols ~~ 24320 2535 ~~ 26.87b 50.85a © Aldehydes ~~ 13221c ~~ 671.57a 527.71ab ~~ 379.24b ~ Otheraroma ~~ 451 ~~ 7.71b ~~ 1954a ~~ 2246a ~ Totalaroma content ~~ 312.69c ~~ 1324.56a ~~ 1014.20a 852.86b © Melatonin ~~ 3550 873 484ab 362 _ Notes: data in the table are mean values of three repeats; and different letters represent no significant difference on 5% level.

5. Effect comparison of different L-tryptophan treatment stages (an application concentration 250 mg/L of the L-tryptophan; root application; an average application amount of about 20 L for each plant; and applied once) As shown in Fig. 6, effects of the L-tryptophan treatment stages (within 15 days before veraison, during veraison and within 15 days after veraison) on aroma and melatonin in fruits are evaluated. The results show that, the characteristic aroma, the aldehyde aroma substances, the other aroma substances and the total aroma content in the fruits are significantly increased at the three L-tryptophan treatment stages. For the characteristic aroma, the aldehyde aroma and the total aroma content, the L-tryptophan treatment during veraison has the optimum effect; and application effects of the L-tryptophan before and after the veraison are significantly higher than that of the control, but are inferior to the effect of the treatment during veraison. For the melatonin, the treatment during veraison has the optimum effect; and the treatment within 15 days before veraison and the treatment within 15 days after veraison have significant differences from the control. The above contrast tests show that, the L-tryptophan treatment during veraison has the optimum effect.

Table 6 Effects of different L-tryptophan treatment stages on content of aroma and melatonin in fruits (unit: ng/g FW) item Control Within 15days Within 15 days after ~~ Veraison before veraison veraison “Characteristic aroma ~~ 151.65d ~~ 552.000 ~~ 326.47c¢ 619.938 Alcohols 24.32b 35.08a 12.91C 25.35b Aldehydes 132.21d 593.44b 380.57¢ 671.57a Other aroma 4.51C 24.56b 7.084 7.71a Total aroma content 312.69d 1205.08b 727.03¢ 1324 .56a Melatonin 3.55b 3.86b 3.00b 8.73a _ Notes: data in the table are mean values of three repeats; and different letters representno significant difference on 5% level.

Each embodiment in the description is described in a progressive way. The difference of each embodiment from each other is the focus of explanation. The same and similar parts among all of the embodiments can be referred to each other. For a device disclosed by the embodiments, because the device corresponds to a method disclosed by the embodiments, the device is simply described. Refer to the description of the method part for the related part.

The above description of the disclosed embodiments enables those skilled in the art to realize or use the present invention. Many modifications to these embodiments will be apparent to those skilled in the art. The general principle defined herein can be realized in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principle and novel features disclosed herein.

Claims (4)

CONCLUSIONS A method for improving the melatonin content and aroma of grape grapes by using L-tryptophan, which method comprises administering L-tryptophan during the véraison of the grapes. The method according to claim 1, wherein the concentration of the L-tryptophan used is 200-300 mg/l; wherein the L-tryptophan is completely applied in one time with it being dripped onto the roots, the average amount applied for each plant being 15 - 25 | amounts to; or wherein the L-tryptophan is sprayed on the foliage all at once with the average amount applied for each plant 0.3 - 0.7 | amounts to. The method of claim 1, wherein the concentration of the administered L-tryptophan is 200-300 mg/L; wherein the L-tryptophan is administered when the soluble solids content in the grape fruits does not exceed 12.0 + 0.5. The method of claim 1, wherein the concentration of the administered L-tryptophan is 200-300 mg/L; wherein the fruits and the tree are regularly managed without any special requirements after the administration of L-tryptophan.