Wednesday, May 11, 2011

cay than ky - cay dieu ky - cay ky dieu deu la mot

Trái thần kỳ

Cay than ky, cay dieu ky hay cay ky dieu deu la 3 cai ten de chi mot loai cay dac biet. Nhung ten goi nay deu am chi kha nang dac biet cua loai cay nay. Cay than ky, qua than ky (miracle tree, miracle fruit) co ten khoa hoc la Synsepalum dulcificum, thuoc ho Sapotaceae. Cay duoc phat hien boi nha tham hiem Chevalier des Marchais nam 1725 cung voi nhieu loai trai khac khi ong du ngoan den vung Tay Phi. Chevalier des Marchais thay nhung tho dan cua bo lac nay thuong hai nhung qua mong do tren canh cay va nhai trong mieng truoc cac bua an. Cay cao khoang 3 m. Qua chin mau do mong, chua mot hat co hat ca phe, duoc thu hoach quanh nam.

Phan tich trong qua than ky thay co chua duong va miraculin. Tuy nhien, ham luong duong trong qua khong cao nhung vi ngot thi rat diu va dac biet. Su “ky dieu” cua qua duoc danh gia cao vi khi an vao thi no khien cho vi chua, cay, dang cua cac loai qua hoac thuc an, thuc uong ke tiep se tro nen ngot. Chang han sau khi nem qua than ky roi nem dich qua chanh thi se thay chanh tro nen ngot vo cung. De giai thich hien tuong nay, co gia thuyet cho rang su tac dong cua cac phan tu miraculin da lam sai lech su dinh huong cua cac thu the cam nhan tren gai luoi, lam cho luoi tro nen thich ung va nhan dinh doc nhat voi vi ngot trong mot khoang thoi gian nhat dinh.

 

Miraculin la mot protein khong ben o nhiet do cao va chi bi phan huy khi dun nong. Vi vay khi nau chin, qua than ky se khong con tac dung tren vi giac nua. Neu dung tuoi thi cam giac ngot  keo dai 1 den 2 gio.

 

Theo Cuc Quan ly Duoc va Thuc pham cua My , nhung che pham co lien quan den qua than ky duoc dan nhan la nhom “thuc pham bo sung” (dietary supplement) thay vi “chat lam ngot” (sweetener). Trong nhung nam dau thap ky 1970, nhung nguoi My an kieng co the mua miraculin o dang vien su dung trong cac bua tiec de tu danh lua vi giac cua ho. Nhung thu chua nhu chanh hoac cac loai do chua (nhu dua chua, rau qua ngam giam chua...); ngot, cay hoac dang nhu cu cai duong, tuong ot, ruou bia... deu tro nen ngot sau khi nem miraculin.

 

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