Chhài-iàn (Hàn-jī: 菜燕) sī ùi red alga, Gelidium kap Gracilaria chia-ê hái-chhài ê sè-pau-piah the̍h-liān chè-chō chhut-lâi ê galactose (he̍k agarose) ê chū-ha̍p-bu̍t, chú-iàu chhut-sán tī Tang-a-chiu, Chile kap Ka-chiu.

Green tea flavored yōkan, a popular Japanese red bean jelly made from agar
A blood agar plate used to culture bacteria and diagnose infection

Chhài-iàn ē iôⁿ tī sio-chúi, léng--khí (40 °C) liáu ē pìⁿ tēng, kian-tàng chò gelatinous ê chōng-thài. I chú-iàu sú-iōng tī bî-seng-bu̍t-ha̍k chò sè-khún pôe-ióng ê châi-liāu. In-ūi ū-hâm tōa-liōng ê chia̍h-mi̍h chhiam-ûi, pī sú-iōng chò kheng-sià-che (laxative), thng ê cheng-tiû-che (thickener); chò-sêng jelly, peng-ki-lîn téng-téng ê chhit-thô-chia̍h. Mā su-iōng tī bih-luh ê kek-òa, chò chē-chheng-che ēng. Tī chit-phín (fabric) chò chiuⁿ-ám (paper sizing) ēng. Tī khí-kho chò ìn-bô·-châi-liāu sú-iōng.