6.2 The Water-solubke vitamin
6.2 The Water-solubke vitamin
Overview of Water-Soluble vitamins a Dissolve in water Generally readily excreted Subject to cooking losses function as a coenzyme Participate in energy metabolism 50-90% of b vitamins are absorbed a Marginal deficiency more common
Overview of Water-Soluble Vitamins ◼ Dissolve in water ◼ Generally readily excreted ◼ Subject to cooking losses ◼ Function as a coenzyme ◼ Participate in energy metabolism ◼ 50-90% of B vitamins are absorbed ◼ Marginal deficiency more common
BVit- VB1(thiamin) + CH2—N CH2—CH20H NH 硫胺素的化学结构 Contains sulfur and nitrogen group Destroyed by alkaline and heat o Coenzyme: Thiamin pyrophosphate(TPp)
一 BVit- VB1 (thiamin) •Contains sulfur and nitrogen group •Destroyed by alkaline and heat •Coenzyme: Thiamin pyrophosphate (TPP)
Stability and Properties ①具有酸碱性质 ②对热非常敏感,在碱性介质中加热易分解. ③能被vB1酶降解,同时,血红蛋白和肌红蛋白可作 为降解的非酶催化剂 ④对光不敏感,在酸性条件下稳定,在碱性及中型 介质中不稳定 ⑤其降解受A影响极大,般在A为050.65范 围降解最快
① 具有酸-碱性质 ② 对热非常敏感,在碱性介质中加热易分解. ③ 能被VB1酶降解,同时,血红蛋白和肌红蛋白可作 为降解的非酶催化剂. ④ 对光不敏感,在酸性条件下稳定,在碱性及中型 介质中不稳定. ⑤ 其降解受AW影响极大,一般在AW为0.5-0.65范 围降解最快. Stability and Properties
谷粉屮的羰基髯 2c ∧级液 的咳系 谷粉、小去粉中 CH 硫胺素和脱羧辅酶降解速率与ρH的关系
硫胺素和脱羧辅酶降解速率与pH的关系