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Cac nha khoa hoc dang khuyen khich dung dau thuc vat thay cho mo de phong benh tim mach. Tuy nhien, neu dung phai dau kem chat luong thi tac hai cung khong kem. Va viec phan biet dau nao tot, dau nao hong chang phai de dang.
De tranh mua nham vao dau pha tron gia, dau kem pham chat, nguoi tieu dung can phai co nhung hieu biet nhat dinh, thong qua phuong phap cam quan nhan xet mui vi, trang thai, mau sac…
Danh gia mui cua dau
Truoc het, phai rua tay that sach, khong dung xa phong thom de tranh lan mui la, gay nhieu khi nhan xet. Lay mot chiec dua sach cham vao dau, roi nho vao long ban tay trai, dung ngon tay tro phai di miet, dan rong dau ra long ban tay roi dua len mui ngui.
Dau co chat luong tot co mui binh thuong, dac trung ro ret cua tung loai dau, khong oi, khong hoi, khong khe, khong khet, khong co mui la, mui kho chiu gi khac.
Nhan xet vi cua dau
Lay mot chiec dua sach cham vao dau va nho 1-2 giot vao cho hom ban tay. Dung luoi nem xem dau co mui vi gi la khong. Neu dau co chat luong tot, huong vi se binh thuong, khong chat, khong dang, khong chua ma chi co huong vi dac trung cua san pham, tuy theo tung loai dau. Khi nem xong, nho bo va suc mieng ky.
Danh gia trang thai trong suot cua dau
Neu dau co pham chat cao, ham luong nuoc va tap chat co rat it thi se trong suot. Neu khong trong suot thi tuy theo do duc nhieu hay it, ta co the danh gia duoc pham chat dau thap hay cao, co ham luong nuoc va tap chat nhieu hay it.
Quan sat ca mau sac anh len cua dau de phan biet loai dau va pham chat. Neu dau dat pham chat tot thi co mau vang sam, dau chat luong binh thuong co mau vang nhat. Neu la dau hat cai thi trong mau vang van thay thoang mau luc, neu la dau lac thi co mau vang nhat hay mau da cam nhat; neu la dau hat bong thi mau vang nhat hon.
Phat hien dau pha tron
De phat hien dau an bi pha tron dau trau, lay mot it dau cho vao ong nghiem, them vao may giot axit sunfuric, dun cach thuy 60 do C trong 15 phut. Neu co dau trau thi se thay dung dich vay len nhu dam may, neu luong dau trau qua nhieu thi se ket thanh mang cuc.
De phat hien viec pha tron them chat co tinh bot vao dau an, lay mot it dau, gio them may giot iod vao, se thay dau xuat hien mau xanh lam.
Dau vung la loai dau quy, khi moi san xuat co mau vang anh hong, dua ra anh sang thay trong suot, khong co chat lang dong o day, khong phan lop, mui vi ro ret. Neu bi pha tron, du chi la 0,5% thanh phan bang nuoc cung co the phat hien duoc: Dau se khong trong suot lam, khong dam dac nhu dau nguyen chat, phan lop, ngui khong thay mui vi thom ngon, lai suc len mui vi khac la vi dau da bi phan giai, oxy hoa, bien chat, hu hong...
(Theo Suc khoe & Doi song)
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