PLANT EXTRACT CONTAINING ANTIFREEZE SUBSTANCE AND METHOD FOR PRODUCING SAME
The objective of the present invention is to provide an antifreeze substance which is suitable for practical use and has excellent antifreeze activity in a safe process flow applicable to food production in a simple, efficient and inexpensive manner. The first method for producing a plant extract containing an antifreeze substance according to the present invention comprises the steps of drying a plant containing the antifreeze substance and extracting the antifreeze substance from the dried plant. The second method for producing a plant extract containing an antifreeze substance according to the present invention comprises the steps of extracting the antifreeze substance from a plant, and treating the obtained extract from the extracting step with an adsorbent.
1 . A method for producing a plant extract containing an antifreeze substance, comprising the steps of
drying a plant containing the antifreeze substance; and
extracting the antifreeze substance from the dried plant.
2 . The production method according to claim 1 , wherein the plant is dried by freeze drying or through-flow drying.
3 . The production method according to claim 1 , wherein the plant extract is further treated with an adsorbent.
4 . The production method according to claim 1 , wherein a sprout is used as the plant.
5 . The production method according to claim 1 , wherein a cruciferous plant is used as the plant.
6 . The production method according to claim 5 , wherein Brassica juncea is used as the plant.
7 . The production method according to claim 1 , wherein the antifreeze substance is extracted using water.
8 . The production method according to claim 1 , further comprising the step of cold-acclimating the plant before drying the plant.
9 . The production method according to claim 8 , wherein the temperature of the cold acclimation is not less than 0° C. and not more than 20° C.
10 . The production method according to claim 8 , wherein the step of the cold acclimation is carried for not less than 3 days.
11 . A plant extract, wherein the plant extract is produced by the production method according to claim 1 and has antifreeze activity.
12 . The plant extract according to claim 11 , wherein an average area of ice crystals measured using a microscope after cooling a plant extract solution containing 30 w/v % of sucrose to −40° C. and heating the plant extract solution to −6° C. is smaller by not less than 5% than an average area of ice crystals measured by the same manner except that the plant extract is not subjected to the drying step.
13 . An antifreeze substance-containing plant extract composition, comprising the plant extract according to claim 11 , or a dry substance of the plant extract according to claim 11 .
14 . A method for producing a plant extract containing an antifreeze substance, comprising the steps of
extracting the antifreeze substance from a plant; and
treating the obtained extract from the extracting step with an adsorbent.
15 . The production method according to claim 14 , wherein an activated carbon, an acrylic synthetic adsorbent, an acrylic cation exchange resin, a methacrylic cation exchange resin or a silica gel is used as the adsorbent.
16 . The production method according to claim 14 , wherein not less than 0.1 parts by weight of the adsorbent relative to 1 part by mass of a protein contained in the extract is used.
17 . The production method according to claim 14 , wherein a sprout is used as the plant.
18 . The production method according to claim 14 , wherein a cruciferous plant is used as the plant.
19 . The production method according to claim 18 , wherein Brassica juncea is used as the plant.
20 . The production method according to claim 14 , wherein the antifreeze substance is extracted with water.
21 . The production method according to claim 14 , further comprising the step of cold-acclimating the plant before drying the plant.
22 . The production method according to claim 21 , wherein the temperature of the cold acclimation is not less than 0° C. and not more than 20° C.
23 . The production method according to claim 21 , wherein the step of the cold acclimation is carried for not less than 3 days.
24 . A plant extract, wherein the plant extract is produced by the production method according to claim 14 and has antifreeze activity.
25 . An antifreeze substance-containing plant extract composition, comprising the plant extract according to claim 24 , or a dry substance of said plant extract.