Mi tam tak chuan freeze‐drying bulpui ber chu vacuum sublimation stage-ah a awm niin an ngai. Dik tak chuan, pre‐freezing hian material chhunga ice crystal structure chhunga awm chu a tichiang a, a tam zawkah chuan final product texture, appearance leh rehydration performance atana lungphum a phum a ni. Pre‐freezing parameters te chu material characteristics nen a inmil lo a nih chuan a hnu lama sublimation hian a chhiatna te chu a khum thei lo.
Pre‐freezing temperature a hniam tawk loh chuan a chhunga thil awmte chu solid ice-ah a vawt kim thei lo. Partial unfrozen liquid chuan vacuum condition hnuaiah melting phenomenon a siam ang. A siam zawh tawh chu a tlahniam ang a, a tlakbuak ang a, surface hardening a awm ang a, loose porous structure tha lo tak a nei ang. Thlai ang chi high‐sugar materials tan chuan super‐cooling phenomenon hi a thleng awlsam hle. Materials chu a chung lamah solid angin a lang a, a chhung lam erawh chuan viscous liquid state a la vawng reng a, hei hi mit saruak atanga hriat harsa tak a ni.
Freezing speed chak lutuk chuan raw material chhungah ice crystal te te a siam ang. Ice crystal te te hian sublimation hnuah pore channel a siam tling dawn lo a, chu chuan thil siam zawh tawhte chu rehydration speed a ti slow hle. Chumi kalh zawng chuan, slow freezing dik taka control chuan ice crystal lian zawk a siam chhuak thin. Sublimation hnuah chuan product chhungah pore passage uniform zawk a awm a, rehydration performance pawh nasa takin a ti tha ang. Mahse slow freezing lutuk hian cell a tichhia thei a, material juice a hloh thei bawk.
Material category hrang hrangah hian pre‐freezing strategy hrang hrang a ngai a. Sa raw materials te hi a then a hmin loh nan deep pre‐freezing uluk taka neih a ngai a ni. Sugar tamna thei rahte chuan super‐cooling effect an neih loh a ngai a ni. Blanching hnua thlai chi hrang hrangte chu cooling rate remchang nen a inmil tur a ni. Operator te chuan material moisture, sugar content leh thickness a zirin temperature gradient leh holding time an set a ngai a ni.
Enterprise-te chuan formal mass production hmain small‐scale process test an zo tur a ni. Target product effect nena inzawm pre‐freezing parameters te chu enfiah rawh. Pre‐freezing process dik tak hian collapse, shrinkage leh discoloration problems a tihziaawm thei a, freeze‐dried food te hmel, thlum leh rehydration property a ti tha thei a ni.
