Flavor adjustment method for produce and device for use in same

Abstract

The present invention provides a method for adjusting a component of a harvested crop, and, in particular, the flavor of produce such as a vegetable or a fruit. According to one embodiment of the present invention, a flavor adjustment method for produce is characterized in that plasma is radiated at one or more irradiation regions on the surface of harvested produce. There may be one plasma irradiation region, or there may be two or more. The plasma may be radiated within an area that is 50% or less of the maximum cross-sectional area of the target produce.

Description

Method for adjusting the taste of fruits and vegetables and device used therefor

[0001] The present invention relates to a method for adjusting the components of agricultural products and an apparatus used therefor, and more specifically to a method for adjusting the taste of post-harvest agricultural products, particularly fresh produce such as fruits and vegetables, and an apparatus used therefor.

[0002] Research is underway into applying plasma, which is said to be the fourth state of matter after solid, liquid, and gas, to the fields of agriculture and food.

[0003] For example, Patent Document 1 proposes a method for producing agricultural products, in which an aqueous solution containing sodium L-lactate is irradiated with atmospheric pressure plasma and the aqueous solution is supplied to soil in which the agricultural products are grown.

[0004] Furthermore, Patent Document 2 proposes a plasma sterilization device that sterilizes agricultural products, which are objects to be sterilized, by plasma discharge between opposing electrodes.

[0005] As described above, various proposals have been made regarding the use of plasma technology for promoting crop growth and disinfecting / sterilizing crops. However, to the best of the inventors' knowledge, there have been few reports of its use from the perspective of post-harvest crop components.

[0006] International Publication No. 2018 / 207667 Japanese Patent Application Laid-Open No. 2015-136605

[0007] In view of the above circumstances, an object of the present invention is to provide a method for adjusting the components, particularly the taste, of harvested agricultural products. Another object of the present invention is to provide an apparatus to be used in the method.

[0008] The present inventors have previously invented a food coating method (Patent Application No. 2020-161535) which involves applying an aqueous solution or an aqueous alcohol solution of a water-soluble and biocompatible raw material compound to the surface of a food product, and then irradiating the surface of the food product with plasma or an electron beam to polymerize the raw material compound and form a polymerized thin film on the surface of the food product.

[0009] The specification of the above patent application describes in the examples treatment conditions (Group 3, Group 3a) in which the surface of Delaware grapes is irradiated with plasma using a plasma irradiation device with argon gas without applying an aqueous solution of the raw material compound, and in particular, it describes that when the surface of the grapes is irradiated with plasma and then a bacterial solution is sprayed onto the surface with a sprayer (Group 3a), the mold growth inhibitory effect was not as great as initially expected. On the other hand, the inventors have found that grapes irradiated with plasma without applying an aqueous solution of the raw material compound tend to have an increased grape aroma after a certain period of time at room temperature.

[0010] Therefore, the present inventors have conducted extensive research and found that the above object can be achieved by the following configuration.

[0011] The method for adjusting the taste of fruits and vegetables of the present invention is characterized by irradiating one or more irradiated areas on the surface of harvested fruits and vegetables with plasma, thereby achieving the above-mentioned object. The plasma irradiation area may be 50% or less of the maximum cross-sectional area of ​​the fruits and vegetables. The fruits and vegetables may be fruit trees. The fruit trees may be citrus fruits, and the irradiated areas may be one or more selected from the group consisting of the stalk, the peel, the apex, and the branches connected to the stalk.

[0012] The fruit and vegetable preservation device of the present invention is characterized by comprising a plasma irradiation means capable of irradiating plasma onto one or more irradiated areas on the surface of harvested fruit and vegetables, and performing the above-mentioned method, thereby achieving the above-mentioned object.

[0013] According to the present invention, the taste of harvested agricultural produce (fruits and vegetables) can be adjusted by irradiating one or more irradiated areas on the surface of the agricultural produce (fruits and vegetables) with plasma.

[0014] Furthermore, according to the present invention, there is provided a device for preserving agricultural produce (fruits and vegetables) that is equipped with a plasma irradiation means capable of irradiating plasma onto one or more irradiated areas on the surface of harvested agricultural produce (fruits and vegetables) and that performs the above-mentioned taste adjustment method.

[0015] (A) Graph showing the relationship between plasma irradiation time (seconds) and the average sugar content (Brix%) of fruit juice in Example 1. (B) Graph showing the relationship between plasma irradiation time (seconds) and the average acidity (%) of fruit juice in Example 1. (A) Graph showing the relationship between the number of days elapsed since plasma irradiation and the average sugar content (Brix%) of fruit juice in Example 2. (B) Graph showing the results of statistical processing of the average sugar content (Brix%) of fruit juice 4 and 5 days after plasma irradiation, by plasma irradiation time (seconds). (A) Graph showing the relationship between the number of days elapsed since plasma irradiation and the average acidity (%) of fruit juice in Example 2. (B) Graph showing the results of statistical processing of the average acidity (%) of fruit juice 4 and 5 days after plasma irradiation, by plasma irradiation time (seconds). Graph comparing the amount of ethylene generated by plasma irradiation and non-irradiation. (A) Mandarin orange (Tangor species), (B) Broccoli. (A) Graph showing the relationship between the plasma irradiation area and the average sugar content (Brix%) of the fruit juice in Example 3. (B) Graph showing the relationship between the plasma irradiation area and the average acidity (%) of the fruit juice in Example 3.

[0016] Hereinafter, embodiments of the present invention will be described in detail.

[0017] In this specification, "crops" typically refers to cultivated plants grown in fields. In addition, plants that grow wild in the mountains and are used for food, i.e., wild vegetables, are also included in crops. Cultivation methods (cultivation techniques) for cultivated plants are not particularly limited. Examples include open-field cultivation, greenhouse cultivation, hydroponic cultivation, forced cultivation, log cultivation, mushroom bed cultivation, and factory cultivation. Semi-cultivation, in which wild plants are manipulated by humans and grown in a state intermediate between wild and cultivated, is also possible.

[0018] As used herein, the term "harvesting" in relation to agricultural crops refers to the harvesting (collection) of agricultural crops. In other words, as used herein, "harvested agricultural crops" refers to harvested agricultural crops (collected agricultural crops). Here, the growth stage of the agricultural crops at the time of harvesting is not particularly limited, and they may be in the growing season or the mature season. Harvested agricultural crops (also referred to as harvested agricultural crops) also include those that have been harvested (collected) at a time unintended by the producer due to damage caused by natural disasters such as heavy rain (heavy rain), light rain (lack of rain), high temperatures (drought), low temperatures (lack of sunshine), gusts of wind, typhoons, tornadoes, snow accumulation, earthquakes, tsunamis, cracks in the ground, and landslides, or damage caused by some human-induced factor. Of course, harvested agricultural crops also include those harvested to avoid damage caused by such natural disasters or human-induced factors.

[0019] In the following, as a representative embodiment of the present invention, an embodiment in which the agricultural product is a fruit or vegetable will be described. However, it should be noted that the present invention is not limited to this embodiment. For example, other embodiments of the agricultural product include cereals (rice; barley, wheat, rye, and other grains; corn; buckwheat, etc.).

[0020] A method for adjusting the taste of fresh produce according to one embodiment of the present invention (hereinafter also referred to as the method according to this embodiment) is characterized by irradiating plasma to one or more irradiated areas on the surface of fresh produce after harvest.

[0021] In this specification, "fruits and vegetables" typically refers to crops obtained from cultivated fruit trees, edible trees, woody plants, herbaceous plants, etc., but wild vegetables are also included in the term "fruits and vegetables."

[0022] Specifically, fruits and vegetables include fruits, vegetables, mushrooms, and wild plants. Fruits refer to fruits that are eaten. Vegetables are classified according to the part used, and include leafy vegetables, root vegetables, and fruiting vegetables. Mushrooms refer to organisms classified as fungi that form fruiting bodies large enough to be seen with the naked eye, or the fruiting bodies themselves, that are eaten. Wild plants refer to plants that grow wild in the mountains and are eaten.

[0023] Examples of fruits include, but are not limited to, akebia, acerola, avocado, apricot, strawberry, fig, plum, mandarin orange, orange, persimmon, quince, kiwi fruit, kiwano, chestnut, guava, grapefruit, citrus fruits, cherry, pomegranate, watermelon, star fruit, plum, pear, cherimoya, Chinese pear, dragon fruit, durian, Japanese pear, nashi, nashi, nashi, banana, pineapple, passion fruit, papaya, loquat, grape, blueberry, prune, quince, mango, melon, peach, lychee, apple, and lemon.

[0024] Among vegetables, examples of leafy vegetables include chives (light onions), scallions (bundle onions), asparagus, cauliflower, cabbage, swiss cabbage, komatsuna (Japanese mustard spinach), shiso (perilla), crown chrysanthemum, celery, onion, bok choy, chives, leeks, Chinese cabbage, broccoli, spinach, mizuna (Japanese mustard greens), mibuna (Japanese bean radish), and lettuce, but are not limited to these.

[0025] Among vegetables, root vegetables include, for example, turnip, burdock, sweet potato, taro, potato, ginger, radish, carrot, garlic, mountain yam, shallot, and radish, but are not limited to these.

[0026] Among vegetables, examples of fruit vegetables include strawberries, green beans, edamame, peas, okra, pumpkin, cucumber, bitter melon, shishito peppers, chili peppers, watermelon, zucchini, broad beans, corn, tomatoes, eggplants, bell peppers, paprika, Japanese melon, and peanuts, but are not limited to these.

[0027] Examples of mushrooms include, but are not limited to, Enoki mushroom, King oyster mushroom, Shiitake mushroom, Nameko mushroom, Hiratake mushroom, Bunashimeji mushroom, Maitake mushroom, and Mushroom.

[0028] Examples of wild vegetables include taros (tarana), koshiabura (Japanese koshiabura), butterbur sprouts (Yamatokihokori), red water lilies (Uwabamisou), green kogomi (Kusasoretsu), red kogomi (Kiyotakishida / Ipponkogomi), fern (zenmai), bowa (Inudouna / Jobusumasou), Ezo-nyū (Saku, Fuji, Nyōsaku), mountain wasabi (mountain horseradish), bracken, Yamaudo (Japanese burdock), dogtooth violets, wild garlic (Ainu leek), urui (Japanese quince), aiko (Miyamai) Examples of suitable herbs include, but are not limited to, Laksa (Japanese maple leaf weed), Anemone japonica (Japanese holly), Japanese knotweed, Japanese wildflower, Japanese parsley, Japanese lily, Japanese lily, Japanese ginseng, Kalopanax gracilis, Chive plant, Horsetail, Japanese silverleaf, Trillium japonica, Kuril bamboo, Kinome (Akebia vine shoots), Zuiki (taro root), Myogatake (ginger), and Watercress (Netherlands).

[0029] Among the examples of fruits, vegetables, and wild plants listed above, there are some that can be classified as both fruits and vegetables (fruit vegetables), such as strawberries. There are also some that can be classified as both vegetables (leafy vegetables), such as chives. It should be noted that, as mentioned above, it may not always be possible to fit a single crop into a single classification for crops included in fruits and vegetables. Meanwhile, although one of the features of the method according to this embodiment is its versatility, it is practically impossible to comprehensively demonstrate its effectiveness for all crops included in fruits and vegetables.

[0030] Therefore, the following describes an example of classification (grouping) of fruits and vegetables when applying the method according to this embodiment, where the classification of applicable crops in the pesticide registration administered by the Ministry of Agriculture, Forestry and Fisheries is referenced. However, it should be noted that pesticides are essentially different in that their purpose is to prevent damage caused by diseases and pests in agricultural crops, whereas the present invention is intended to adjust the components (taste) of agricultural crops. Reference URLs: https: / / www.maff.go.jp / j / nouyaku / n_sasshin / group / top.html https: / / www.maff.go.jp / j / nouyaku / n_sasshin / group / sakumotu_bunrui.html

[0031] In this embodiment, fruits and vegetables include fruits, vegetables, and edible fungi.

[0032] Fruit trees include citrus fruits, pome fruits, stone fruits, berries and other small fruits.

[0033] Citrus fruits include kabuchi, kabosu, kumquats (Ninpo kumquat, Maru kumquat), shikuwasa, jabara, sudachi, tarogayo, Nagato yuzukichi, Heibei vinegar, yuzu, lime, lemon, amakusa, encore, Iyokan, Daiko mikan, orange (sweet orange, Valencia orange), kara (kara mandarin), kiyomi, saga mandarin, shiranui (dekopon), setoka, seminole, tankan, navel (navel orange), haruka, harumi, harehime, hyuganatsu, ponkan, marcott, mandarins (unshu mandarins, kishu mandarins), kawachi bankan, grapefruit, summer fresh, natsumikan (amanatsu, natsudaidai), hassaku, pomegranate (zabon, bontan, banpeiyu, uchimurasaki), and hybrids between these crops.

[0034] Pome fruits include quince, pear (Japanese pear, Western pear, Chinese pear), loquat, quince, and apple.

[0035] Stone fruits include peaches, small stone fruits, and cherries. Peaches include peaches and nectarines. Small stone fruits include apricots, Japanese apricots, plums, and prunes, as well as hybrids between these crops.

[0036] Small fruits such as berries include blackberries, boysenberries, raspberries, aronia (chocoberry), seaberries (seabuckthorn, sea buckthorn, sea buckthorn), currants (gooseberries), haskap (honeysuckle), currants (currants, currants, red currants), blueberries, mulberries (autumn mulberry, giant mulberry, winter mulberry, summer mulberry), edible mulberries (Japanese mulberry, Japanese mountain mulberry), Japanese bayberry, Japanese mulberry, and grapes (large-sized grapes, small-sized grapes).

[0037] Vegetables include tuberous and corm vegetables, root vegetables, bulb vegetables, pulses (seeds), legume vegetables (immature), fruiting vegetables (cucurbits), fruiting vegetables (solanaceous plants), brassica vegetables (flowerhead and stem Brassicas), leafy vegetables, stalk and stem vegetables, and edible flowers.

[0038] Examples of potatoes include American groundnut (apios), sweet potato (satsumaimo, simonimo), Jerusalem artichoke (butaimo), konjac, taro (ebiimo, bamboo shoot, yatsugashira, Celebes), Chinese yam, lotus root (tuber), potato (potato), water yam (taimo), yacon, and wild yam (yamatoimo, jinjaimo, nagaimo).

[0039] Root vegetables include green cabbage (Detroit Dark Red, red beet, garden beet), turnip (red turnip, red cabbage, Atsumi turnip), burdock, burdock (salsify, brahmandine, salsify), celeriac (celeriac root, celeriac root), daikon (radish leaf radish, daikon), chicory (chicken stump), sugar beet (sugar beet), carrot (kintoki carrot, western carrot, island carrot), carrot leaves, hatsuka daikon (Hatsuni Daikon) These include: medicinal carrot (seed carrot, Korean ginseng, Korean ginseng), wasabi radish (horseradish, horseradish), turmeric (autumn turmeric, kyoou, spring turmeric), ginger (ginger root), purple turmeric (zedoary), kanokoso (haruominaeshi), licorice (Uralkanzo, Spanish licorice), edible sweet potato, edible bellflower (root), and forest thistle (mountain burdock, burdock thistle).

[0040] Bulbs include root bulbs (bulb onions) and leaf bulbs (green onions). Root bulbs include onions, green onions, edible lilies (yurine), garlic (jumbo garlic, elephant garlic, greathead garlic), leaf garlic, Belgian shallots (shallots), rakkyo (rakkyo), and nobiru. Leaf bulbs include chives (scallions, scallions), chives (Siberian leek, chives, chives), garlic (yellow chives), garlic (flower buds), green onions (Kujo leek, Kaga futo leek, Senju leek, Yagura leek, Shimonita leek, leek, and leek), scallions, Gyoja garlic, and chive (flower stalk) (flower chives).

[0041] Beans (seeds) include azuki beans (dainagon), kidney beans (haricot bean, kintoki bean, tiger bean, uzura pea), cowpea, broad bean, soybean, sword bean, hyacinth bean (senkoku bean, kaga tsurumame, tsurumame), scarlet beans (hanamame), peas, and peanuts (nanakon bean, peanut).

[0042] Beans (immature) include edamame (green beans), string beans (french beans, Moroccan beans), immature cowpeas (juroku cowpeas, Akishima cowpeas), immature wedge beans (urizun, tousai), immature broad beans, immature beans, immature hyacinth beans (immature senkoku beans, immature Kagatsurumame, immature Gyakumame), snow peas (silver peas, snack peas, sugar peas, snap peas), and peas (thin green peas, green peas).

[0043] Cucurbits include immature and mature cucurbits. Immature cucurbits include cucumber (Otogoto Akauri), cucumber flower, edible gourd, edible loofah, zucchini, zucchini flower, gourd (kamouri, winter melon), bitter melon (tsurureishi), chayote (chayote), kanpyo (kanpyo), white melon (aouri, karimori, hagurauri, aoshimari, kurouri, katsurauri), and red-haired melon (mowi). Mature cucurbits include pumpkins (Japanese pumpkin, Western pumpkin, pepo pumpkin (excluding zucchini)), watermelon, melons (Kiku melon, Ginsen, Kintaro), and melons (Earl's melon, Amus melon, Andes melon).

[0044] Solanaceae fruit vegetables include ground cherries (golden berries, tomatillos, and ground cherries), tomatoes, cherry tomatoes, eggplants, bell peppers, and hot peppers. Bell peppers and hot peppers include sweet peppers (Fushimi peppers, Manganji peppers, and Sanbo peppers), Kagura Nanban peppers, Kidachi peppers, shishito peppers (shishito peppers, lion peppers, and Aoi shishito peppers), chili peppers (Takanotsume peppers, Yabusa peppers, Nikko peppers, and Sapporo Onaga peppers), habanero peppers, bell peppers (Oshishishi peppers, California Wonder peppers, colored peppers, and Dutch paprika), and picante peppers.

[0045] Brassica vegetables (flower buds and stems) include flowerhead Brassicas and stem Brassicas. Flowerhead vegetables include cauliflower, broccoli, and stem broccoli (Stick Senor). Brassica stem vegetables include kohlrabi (corm kalan, turnip cabbage), and pickled mustard greens (takenoko takana, stem takana, Umino (enlarged stem), Sichuan pickled mustard greens (enlarged stem)).

[0046] Leafy vegetables include non-heading Brassica leafy vegetables, head Brassica leafy vegetables, Apiaceae leafy vegetables, lettuce (lettuce, chicory, and endive), Asteraceae leafy vegetables other than lettuce (Asteraceae leafy vegetables, except lettuce, chicory, and endive), Lamiaceae leafy vegetables, and Amaranthaceae leafy vegetables.

[0047] Non-heading Brassicaceae leafy vegetables include turnip (Kisona, Nakajimana (Nakajimana)), mustard (yellow mustard, leaf mustard, serifon), kale (Hagoromokaran, Ryokuyokanran), komatsuna (Komatsuna), Tatsoi (Sendai Yukina, Tatsoi, Kisaragi-na), bok choy (Pakchoi), shepherd's purse, bok choy, field wasabi (Okawasabi), field wasabi (rhizome), field wasabi (leaf), mizuna (mizuna, mibuna), arugula (rocket, galgil, eruka), azami (chirimen karaashi, hagoromo karashina), ajimamina (ajimina), oil lettuce (Sendai bashona, hatakena, Himeji wakana, yamamatona), unno (stem and leaves), otakana, These include Oyama-sodatechi, Cavolo Nero (black cabbage), Kahokuna (Kahokuna), Kale arugula, Sagami Green, Sanukina, Sichuan pickled cabbage (Takenoko Takana), Senpo-sai (Senpo-sai No. 1, Senpo-sai No. 2), Tai-chu-sai (Hao-chi-na), Takana (Katsuona, Seisai, Yamagata Aona, Miike Takana), Tabe-na, Bok-gen arugula, Tegoro-na, Turnips (Asamakona, Asukko, Aletta), Nozawana (Nozawana), Non-heading Chinese cabbage (Ogura Hakusai-na, Santo-sai, Shirona), Non-heading Brussels sprouts (Petit Vert, Mini Vert), Benrinai, Mochi-na (New Year's cabbage), Yamagata Midorina, Rafano Brassica, Wasabi-na, and hybrids between these crops.

[0048] Heading Brassica leafy vegetables include cabbage (chilimen cabbage, savoy cabbage), Chinese cabbage, Brussels sprouts (brussels sprouts, komochikanran), and hybrids between these crops.

[0049] Leafy vegetables in the Umbelliferae family include caraway (leaves) (caraway), silver cabbage (soup celery, xiang cai, Chinese jelly, qin cai, mini white), coriander (leaves) (cilantro, xiang cai, coriander), dill (leaves) (dill, dill), parsley (mossard parsley, Italian parsley), fennel (leaves) (uikyo, sticchio), chervil (foeniculum jelly, chervil), mitsuba (green mitsuba, cut mitsuba, root mitsuba), celery, angelica tree, Japanese parsley, touki (leaves), hamanbofu (leaves), and peony (chomeigusa, sakuna, chomeigusa).

[0050] Lettuce includes endive, radicchio, non-heading lettuce (salad, salad, standing lettuce, leaf lettuce), crisphead lettuce, and puntarella.

[0051] Leafy vegetables in the Asteraceae family other than lettuce include chrysanthemum (leaves) (Kikuba), garland chrysanthemum (Kikuna, Stick Garland Chrysanthemum), edible dandelion (edible dandelion, dandelion), curry plant, tarragon (Estragon, French tarragon, Russian tarragon), mugwort, water laurel (Kintoki-so, Handama), Japanese thistle (Sawa-azami), leaf burdock, leafwort (Gogyo, Ogyo), narrow-leaved burdock (Nigana, Njana), maple grass (Shidoke, Momijikusa, Taikouna, Toukichina), yacon (stems and leaves), night herb (Bonna, Honna), and morning glory (Hagina).

[0052] Lamiaceae leafy vegetables include perilla (leaves), oregano (origanum vulgare, wild marjoram), shiso (shiso), sage (common sage, pineapple sage, cherry sage, red sage), thyme (common thyme, creeping thyme, lemon thyme), basil (sweet basil, dark opal basil, basil), mint (mint, spearmint, peppermint, apple mint), marjoram (sweet marjoram, pot marjoram, golden marjoram, marjoram), lemon balm (mentha piperita), and rosemary (rosemary).

[0053] Amaranthaceae leafy vegetables include amaranth (stems and leaves) (Amaranthus japonica, Amaranthus rhododendron, Amaranthus rhododendron), common chard (Betrave, Red common chard, Swiss chard, Detroit), spinach, hijiki (Kusa hijiki, Okamil, Myrna), ice plant, vine (Hamana, Hamajisha), chili pepper (leaves), marsh (corn salad, marsh lettuce), mulukhiyah (Taiwan tuna, Shima tuna), sweet potato (stems and leaves), water spinach (Spinach, morning glory, water spinach, Tsuna, Iosai), and Orandawaremoko. These include salad burnet, borage, lemongrass (melissa grass, lemon grass, fever grass), arrowroot (araliaceae, scutellaria, parvum), shrimp stalk (stems and leaves) (rokkakusou), seaweed, Japanese anemone, cucumber (leaves), edible sorrel (sorrel, oseille), purple morning glory (sinthium saccharum), dokudami, chickweed (small chickweed, green chickweed), habusou (stems and leaves), willow weed (ayutan, hontade, matade), snowdrop, and lemon verbena.

[0054] Stem vegetables include the Taro Petioles and the Fuki (Giant butterbur) group. The Fuki group includes the taro (petiole) (zuiki, daituimo), water yam (petiole) (taimo), and lotus yam (petiole). The Fuki group includes butterbur, Japanese butterbur, asparagus, burdock, grass plants (kogomi, gansoku, kogome, kugumi, and sycamore), fern, bracken, stem lettuce (yamakurage, tomusha, and stem lettuce), Florence fennel, rhubarb, and itadori (sprouts).

[0055] Edible flowers include daylilies (flowers) (Chinese daylilies, Japanese daylilies, daylilies in the bush, yellow flower cabbage, golden needle cabbage), edible marigolds (calendula), edible nasturtiums (nasturtiums), edible pansies, edible asters (Ezo daisies), edible impatiens (African impatiens, New Guinea impatiens), edible exocarpus, edible carnations, edible chrysanthemums, and edible snapdragons. These include edible cosmos, edible cineraria (cineraria), edible stock, edible daisy, edible cosmos (cypress), edible torenia (bean), edible dianthus (nadeshiko), edible primula (edible cherry blossom), edible petunia, edible safflower (flower), edible pentas, edible mini rose, edible daisy, edible English lavender, edible rudbeckia (flowering okra), and flowering okra.

[0056] Mushrooms include Enokitake, King Oyster Mushroom (Kaori Oyster Mushroom), Shiitake, Nameko, Hiratake, Bunashimeji, Maitake, and Tsukuritake.

[0057] As mentioned above, the present invention has a fundamentally different technical concept from pesticides. On the other hand, under the current pesticide registration system, pesticides can be registered by determining the "methods by which they may be used" not only for individual crops such as "apples" or "pears" but also for groups including such crops (e.g., "pome fruits"). This concept can also be applied to the present invention.

[0058] For example, in the examples described below, an example using "mandarin oranges (Satsuma mandarins)" is described, but the conditions applicable to mandarin oranges (selection of the irradiated area, plasma irradiation time, standing time after plasma irradiation, etc.) can be applied not only to mandarin oranges but also to crops classified as "citrus fruits" (e.g., kabosu, kumquat, shikwasa, sudachi, yuzu, lemon, orange, kiyomi, setoka, haruka, harumi, hyuganatsu, grapefruit, natsumikan, hassaku, etc.). On the other hand, unlike pesticides, the method of the present invention does not require a residual concentration, and therefore is highly versatile. The conditions applicable to citrus fruits can be applied to other categories of fruit trees, either directly or by modifying the conditions appropriately taking into account the shape and size of the harvested crop. Furthermore, it can also be applied to vegetables, mushrooms, and the fruits, vegetables (leafy vegetables, root vegetables, fruit vegetables), mushrooms, and wild vegetables exemplified above.

[0059] In the method according to the present embodiment, the area of ​​the harvested fruit or vegetable to which the plasma is irradiated (i.e., the irradiated area) is one or more areas on the surface of the fruit or vegetable. In other words, in the method according to the present embodiment, the area to be irradiated with the plasma may be one or two or more. When the area to be irradiated with the plasma is one, the taste of the target fruit or vegetable can be adjusted efficiently in a short time. On the other hand, depending on the shape, size, etc. of the target fruit or vegetable, the taste may be adjusted more effectively by irradiating two or more areas with the plasma.

[0060] The plasma may be applied continuously or intermittently to a selected irradiated area. More specifically, the plasma may be applied continuously or intermittently to an area of ​​50% or less of the maximum cross-sectional area of ​​the target fruit or vegetable. The plasma may also be applied to a narrower area. For example, the area may be 45% or less, 40% or less, 30% or less, 25% or less, 20% or less, 15% or less, or 10% or less of the maximum cross-sectional area of ​​the target fruit or vegetable.

[0061] Here, the cross-sectional area is used to describe the plasma irradiation range because target fruits and vegetables vary in shape and size, making it difficult to define the maximum surface area that can be irradiated with plasma. While it is technically possible to measure the surface area of ​​a target object using a coordinate measuring machine or the like, there are cases where measuring the surface area of ​​a target object using such a measuring device is practically impossible. In other words, the method according to the present embodiment does not require plasma irradiation of the entire surface of the target fruit or vegetable, as in conventional methods for sterilizing and disinfecting agricultural produce. Therefore, the plasma irradiation range does not need to be determined based on surface area. Rather, unlike sterilization and disinfection methods using plasma technology, the method according to the present embodiment can achieve a sufficient effect of adjusting the taste by irradiating a specific area of ​​the surface of the target fruit or vegetable with plasma. In one exemplary aspect, the plasma irradiation range may be a single point on a selected irradiated area (e.g., an area with a diameter of 1 cm or less).

[0062] For example, in an embodiment where the fruit or vegetable is a citrus fruit (such as a mandarin orange), examples of the areas to be irradiated with plasma include the stalk (calyx), the peel, the apex (the area opposite the calyx), and the branches connected to the stalk. Also, in an embodiment where the fruit or vegetable is a pome fruit (such as an apple), examples of the areas to be irradiated with plasma include the stalk (calyx), the stalk cavity, the peel, the calyx (the area opposite the calyx), the calyx cavity, and the branches connected to the stalk.

[0063] Here, branches connected to the peduncle (peduncle) can be effective in cases where the fruit is harvested (collected) at a time unintended by the producer due to damage caused by a natural disaster or some other human-caused factor, as described above. In other words, if harvested fruits and vegetables contain parts that would not be harvested (collected) during normal harvesting, these parts are considered to be inedible, and if these inedible parts are connected to other parts, including edible parts, they may be irradiated with plasma. In such cases, even if there is concern that consumers and others may have a negative sensory impression of the plasma treatment, this can be an element that dispels such concerns.

[0064] The method for adjusting the taste of fruits and vegetables according to this embodiment can be performed using an apparatus equipped with a plasma irradiation means capable of irradiating plasma onto one or more irradiated portions on the surface of harvested fruits and vegetables. The apparatus may be a so-called dedicated apparatus for performing the method according to this embodiment, or may be an existing apparatus to which the plasma irradiation means has been added as one of its components. In the latter case, an example is a preservation apparatus such as a conventional freezer or refrigerator to which the plasma irradiation means has been added. In this case, a user (such as a producer, consumer, processor, distributor, or retailer of fruits and vegetables) can preserve the fruits and vegetables by applying the method according to this embodiment to the target fruits and vegetables and then freezing or refrigerating them.

[0065] Hereinafter, the embodiments of the present invention will be described in more detail based on examples, but the scope of the present invention should not be construed as being limited by the examples shown below.

[0066] [Example 1] Mandarin oranges (Satsuma mandarins) were used as fruits and vegetables. The mandarin oranges used in this example were all early-ripening mandarin oranges grown in the same farm and harvested at the same time. Similarly, in the following examples, the mandarin oranges before being divided into each group were grown in the same farm and harvested at the same time.

[0067] A total of 60 mandarins were divided into six groups of 10 mandarins each, and atmospheric pressure plasma was continuously irradiated onto a single point on the peel of each mandarin orange (within a diameter of approximately 1 cm) for 0 seconds (control), 10 seconds, 60 seconds, 180 seconds, 300 seconds, or 600 seconds using a plasma irradiation device (manufactured by API Corporation).The mandarins were then left to stand at room temperature (approximately 20°C) for 4 or 5 days, after which the sugar content (Brix value) and acidity of the juice squeezed out from the halves were measured using a sugar-acidity meter (manufactured by Atago Corporation, PAL-BXIACID).

[0068] The results are shown in Figures 1(A) and 1(B). Figure 1(A) is a graph showing the relationship between plasma irradiation time (seconds) and the average sugar content (Brix%) of the fruit juice, and Figure 1(B) is a graph showing the relationship between plasma irradiation time (seconds) and the average acidity (%) of the fruit juice. In Figures 1(A) and 1(B), "*" indicates "p<0.05" for the 60-second irradiation group, and "**" indicates "p<0.01" for the 60-second irradiation group.

[0069] As shown in Figure 1 (A), the sugar content was slightly lower in the 10-second irradiation group compared to the unirradiated group (0-second irradiation group). On the other hand, the 60-second irradiation group, 180-second irradiation group, and 300-second irradiation group all had higher values ​​than the unirradiated group, with the 60-second irradiation group having the highest sugar content, approximately 1.80% higher than the unirradiated group. The 180-second irradiation group also had a value approximately 1.30% higher than the unirradiated group. The 600-second irradiation group had a sugar content similar to that of the unirradiated group.

[0070] As shown in Figure 1(B), the acidity of the 60-second irradiation group was significantly higher than that of the other groups, and was approximately 0.32% higher than that of the unirradiated group. On the other hand, the 10-second, 180-second, and 300-second irradiation groups had higher values ​​than the unirradiated group, but the difference was within approximately 0.10%. Furthermore, the 600-second irradiation group showed a decrease of approximately 0.05% compared to the unirradiated group.

[0071] Here, the results shown in FIGS. 1A and 1B are summarized based on the non-irradiated group as shown in Table 1 below.

[0072]

[0073] As shown in Table 1, this example showed that the taste of harvested fruits and vegetables (specifically, the sugar content and acidity of citrus fruits) could be adjusted by adjusting the plasma irradiation time. In particular, it was suggested that with the intensity of the plasma irradiated from the plasma irradiation device used in this example, setting the irradiation time to 60 to 180 seconds would increase both the sugar content and acidity.

[0074] Example 2 Next, a total of 166 mandarins were divided into three groups, and a single point on the peel of each mandarin orange (within a diameter of approximately 1 cm) was continuously irradiated with atmospheric pressure plasma for 0 seconds (control), 60 seconds, or 180 seconds using a plasma irradiation device (manufactured by API Corporation). The mandarins were then left to stand at room temperature (approximately 20°C) for 0, 1, 3, 4, 5, or 7 days, after which the sugar content (Brix value) and acidity of the juice squeezed out of each mandarin orange were measured using a sugar-acidity meter (manufactured by Atago Corporation, PAL-BXIACID). The number of samples (n) for which the sugar content and acidity of the juice were measured for each group is shown in Table 2 below.

[0075]

[0076] The results are shown in Figures 2(A), 2(B), 3(A), and 3(B). Figure 2(A) is a graph showing the relationship between the number of days after plasma irradiation and the average sugar content (Brix%) of the fruit juice. Figure 2(B) is a graph showing the results of statistical processing of the average sugar content (Brix%) of the fruit juice 4 and 5 days after plasma irradiation, broken down by plasma irradiation time (seconds). In Figure 2(A), the black squares represent the unirradiated group (0-second irradiation group), the black triangles represent the 60-second irradiation group, and the black circles represent the 180-second irradiation group. Figure 3(A) is a graph showing the relationship between the number of days after plasma irradiation and the average acidity (%) of the fruit juice. Figure 3(B) is a graph showing the results of statistical processing of the average acidity (%) of the fruit juice 4 and 5 days after plasma irradiation, broken down by plasma irradiation time (seconds). In FIG. 3A, the plots of black squares represent the unirradiated group (0-second irradiation group), the plots of black triangles represent the 60-second irradiation group, and the plots of black circles represent the 180-second irradiation group.

[0077] As shown in Figure 2(A), the sugar content in the 180-second irradiation group increased three days after plasma irradiation, with even higher values ​​obtained four and five days later. Meanwhile, in the 60-second irradiation group, sugar content increased from three to four days after plasma irradiation, with values ​​four and five days later being comparable to those in the 180-second irradiation group. In contrast, the unirradiated group showed a slight tendency to increase four and five days after the start of the test, but the difference from the value at the start of the test was less than 1.00% in both cases.

[0078] As shown in Figure 2(B), further examination of the sugar content 4 and 5 days after plasma irradiation (after the start of the test) revealed that the results obtained in the 60-second irradiation group and the 180-second irradiation group both showed significant differences compared to the unirradiated group.

[0079] As shown in Figure 3(A), in the 180-second irradiation group, acidity increased three days after plasma irradiation, reached a higher value after four days, then gradually decreased, and reached a value roughly equivalent to that immediately after plasma irradiation after seven days. Meanwhile, in the 60-second irradiation group, acidity increased from three to four days after plasma irradiation, then decreased to roughly the same value as immediately after plasma irradiation by seven days. In contrast, in the unirradiated group, although the decrease four days after the start of the test was somewhat larger, the overall trend was for acidity to decrease gradually over time.

[0080] As shown in Figure 3(B), further examination of the acidity 4 and 5 days after plasma irradiation (after the start of the test) revealed that the results obtained in the 60-second irradiation group in particular were significantly different from those in the unirradiated group.

[0081] As described above, this example shows that plasma irradiation time affects the change in taste (sugar content and acidity) of harvested fruits and vegetables. Specifically, in citrus fruits, significant differences can be seen 4 and 5 days after plasma irradiation compared to the unexposed group.

[0082] In addition, when the mandarin oranges were eaten 4 and 5 days after plasma irradiation, a clear difference in taste was observed between the plasma-irradiated group (180-second irradiation group) and the unirradiated group (n=3).

[0083] Referring again to Figures 2(A) and 3(A), it can be seen that the sugar content and acidity of each group converged within a certain range seven days after plasma irradiation (after the start of the test). In particular, the acidity shown in Figure 3(A) changes over time differently in the unirradiated group, the 60-second irradiation group, and the 180-second irradiation group, but converges to similar values ​​after seven days. These results suggest that a different mechanism may be at work in the plasma-irradiated group than in the unirradiated group, i.e., the ripening (also known as after-ripening) that can occur in typical post-harvest fruits and vegetables.

[0084] In other words, it can be considered that the plasma irradiation of the irradiated surface area of ​​fruits and vegetables according to the present invention triggers (stimulates) a mechanism that does not normally function in harvested fruits and vegetables, or a latent mechanism, which can be confirmed as a phenomenon of a change in taste (sugar content and acidity) after a certain period of time has passed. Although the details of such a mechanism (action mechanism) are not necessarily clear, the inventors believe that there is a certain relationship between the amount of hormones in harvested fruits and vegetables and their taste (sugar content and acidity), and that plasma irradiation may change the amount of hormones (hormone balance), thereby changing the taste (sugar content and acidity).

[0085] To verify this, the following test was conducted using mandarin oranges (Setoka and Harumi, also known as tangor varieties) and broccoli purchased from a greengrocer. (Test procedure) Three mandarin oranges were prepared each with a total weight of 270g ± 20g, and divided into two groups: a control group and a plasma-irradiated group. Two bunches (weighing 40g ± 5g) were cut from each of three broccoli plants, and divided into two groups: a control group and a plasma-irradiated group. A single point (approximately 1 cm in diameter) on the outer skin of the mandarin oranges and the cross section of the broccoli was continuously irradiated with atmospheric pressure plasma using a plasma irradiation device (manufactured by API Corporation) for 0 seconds (control group) and 60 seconds (plasma irradiation group).The mandarin oranges were left at room temperature (approximately 20°C) for two days, and the broccoli was left in a cool, dark place (approximately 10°C) for two days, after which the ethylene levels were measured using a sensor gas chromatograph (manufactured by Nissha FIS, SGEA-P3-C) (n=3 for each mandarin orange and broccoli group).The broccoli was left at room temperature for two hours prior to measurement.

[0086] To measure the amount of ethylene using a sensor gas chromatograph, a test sample is stored in a sealed container, to which a sample collection tube and a sample circulation tube are connected. The other ends of the sample collection tube and the sample circulation tube are connected to a chromatograph (analyzer), allowing the collected sample to circulate between the container and the analyzer at all times. In the analyzer, a chromatogram is obtained by injecting the sample into a column at predetermined time intervals.

[0087] In this test, three mandarin oranges from each group were stored together in an airtight container (a plastic airtight container with a lid, commonly known as Tupperware) as test samples, and one floret from each of three broccoli plants from each group (a total of three florets) was stored together in an airtight container (a plastic airtight container with a lid, commonly known as Tupperware) as test samples. Chromatograms were obtained every 10 minutes for air samples (5 cc) collected from the containers via a sampling tube, and the ethylene levels were converted using the calibration curve data.

[0088] The results are shown in Figures 4(A) and 4(B). Figure 4(A) is a graph comparing the amount of ethylene generated by mandarin oranges exposed to plasma with that by non-exposure, and Figure 4(B) is a graph comparing the amount of ethylene generated by broccoli exposed to plasma with that by non-exposure. Both graphs are based on chromatograms acquired 30 minutes after the start of measurement. As shown in Figures 4(A) and (B), in both mandarin oranges and broccoli, the plasma-exposed group (60-second exposure group) tended to produce higher ethylene levels than the control group (non-exposure group). In particular, the ethylene levels measured in mandarin oranges were approximately eight times higher than those in the control group (non-exposure group), and in broccoli, the ethylene levels measured were approximately twice as high as those in the control group (non-exposure group).

[0089] Example 3 Next, a total of 50 mandarin oranges were divided into five groups of 10 oranges each. In four of the groups, the plasma irradiation sites were the branches, the stalk (stem), the peel, or the apex (the area opposite the stem). A single point (an area approximately 1 cm in diameter) on each site was continuously irradiated with atmospheric pressure plasma for 60 seconds using a plasma irradiation device (manufactured by API Corporation). After leaving the oranges at room temperature (approximately 20°C) for four or five days, the peels were peeled off, and the sugar content (Brix value) and acidity of the juice were measured using a sugar-acidity meter (manufactured by Atago Corporation, PAL-BXIACID). The remaining group served as a control, and after leaving the oranges for four or five days without plasma irradiation, the sugar content (Brix value) and acidity of the juice were similarly measured.

[0090] Furthermore, the branch, which was one of the irradiated areas, was connected to the stalk of the mandarin orange. In other words, the mandarin oranges in the group where the branch was the irradiated area were harvested with the branch remaining about 1 cm from the stalk.

[0091] The results are shown in Figures 5(A) and 5(B). Figure 5(A) is a graph showing the relationship between the plasma irradiation area and the average sugar content (Brix%) of the fruit juice, and Figure 5(B) is a graph showing the relationship between the plasma irradiation area and the average acidity (%) of the fruit juice. In Figures 5(A) and 5(B), "*" indicates "p<0.05" compared to the unirradiated group, and "**" indicates "p<0.01" compared to the unirradiated group.

[0092] As shown in Figure 5(A), the sugar content of the branch-irradiated group, the peduncle-irradiated group, the outer skin-irradiated group, and the apex-irradiated group was approximately 1.80% or more higher than that of the control group (unirradiated group), showing a significant increase. Also, as shown in Figure 5(B), the acidity of the branch-irradiated group, the peduncle-irradiated group, the outer skin-irradiated group, and the apex-irradiated group was approximately 0.20% or more higher than that of the control group (unirradiated group), showing a significant increase.

[0093] These results demonstrate that the taste (sugar content and acidity) of harvested fruits and vegetables can be adjusted by irradiating plasma onto selected areas on the surface of the fruits and vegetables.

[0094] It is particularly noteworthy that the branch irradiation group showed similar results to the other irradiation groups, i.e., increases in sugar content and acidity. Generally, when harvesting mandarin oranges, the fruit is cut off at the edge of the stalk, but if the fruit falls unintentionally, the stalk may remain connected to the branch. Usually, mandarin oranges harvested in this manner are difficult to supply to the market and are often discarded. However, according to the present invention, it is possible to adjust the taste (sugar content and acidity) of such mandarin oranges (fruit trees) to be close to or comparable to those harvested at the original harvest time.

[0095] Furthermore, depending on the type of crop, even if the irradiated area is not an edible area, if there are concerns about changes in appearance due to plasma irradiation, it is possible to select an area to be irradiated that is unlikely to affect the commercial value of the crop.

[0096] In the above-described embodiment, plasma was continuously irradiated onto one point on the irradiated area (within a range of approximately 1 cm in diameter), but it is believed that the same effect can be obtained even if plasma is irradiated intermittently.

[0097] According to the present invention, the taste of harvested agricultural products can be adjusted by irradiating a selected portion of the surface of the agricultural product with plasma. Therefore, the present invention is expected to be applicable in various situations, such as agricultural production, processing, distribution, retail, preservation, and storage. Furthermore, it is expected that the present invention will expand the possibilities for utilizing agricultural products that have traditionally been unavoidably discarded, thereby contributing to the reduction of food waste.

Claims

1. A method for adjusting the taste of fruits and vegetables, comprising irradiating one or more irradiated areas on the surface of harvested fruits and vegetables with plasma.

2. The method according to claim 1, wherein the plasma is irradiated to an area of ​​50% or less of the maximum cross-sectional area of ​​the fruit or vegetable.

3. The method of claim 1, wherein the fruit or vegetable is a fruit tree.

4. The method according to claim 3, wherein the fruit tree is a citrus fruit, and the irradiated area is one or more selected from the group consisting of a stalk, an outer skin, a fruit tip, and a branch connected to the stalk.

5. A fruit and vegetable preservation device comprising a plasma irradiation means capable of irradiating plasma onto one or more irradiated sites on the surface of harvested fruit and vegetable, and performing the method according to any one of claims 1 to 4.