Measurement of water content and water activity
Measurement of water content and water activity
Contents 1.Introduction 2.Structure of water 3.Categories of water in food 4.Water-solute interaction 5.Measurement of water content 6.Water activity 7.Measurement of water activity
Contents 1.Introduction 2. Structure of water 3.Categories of water in food 4. Water-solute interaction 5. Measurement of water content 6. Water activity 7. Measurement of water activity
Introduction
Introduction
We live by the grace of water National Geographic Special Edition,Nov.1993 Water is H2O,hydrogen two parts,oxygen one,but there is also a third thing,that makes it water and nobody knows what it is. D H Lawrence (1885-1930) 'We may ask why all trees and bushes or at least most of them -unfold a flower in a five-sided pattern,with five petals.Some botanist might well examine the sap of plants to see if any difference there corresponds to the shapes of their flowers. Johannes Keplar
We live by the grace of water “ Water is H2O, hydrogen two parts, oxygen one, but there is also a third thing, that makes it water and nobody knows what it is.” D H Lawrence (1885-1930) “We may ask why all trees and bushes – or at least most of them –unfold a flower in a five-sided pattern, with five petals.Some botanist might well examine the sap of plants to see if any difference there corresponds to the shapes of their flowers.” Johannes Keplar National Geographic Special Edition, Nov. 1993
水遁道 细胞膜 离子地道 图！通过细胞壁的分子通道 细胞和外部世界（包括其它细胞）之间的分离壁是远离不渗透壳的。相反， 它是为不同的通道所贯通的。许多这样的通道专门为特殊的离子或分子所使用 而且不允许其它类型的物质通过。图左为水通道，图右是离子通道
图! 通过细胞壁的分子通道 细胞和外部世界（包括其它细胞）之间的分离壁是远离不渗透壳的。相反， 它是为不同的通道所贯通的。许多这样的通道专门为特殊的离子或分子所使用 而且不允许其它类型的物质通过。图左为水通道，图右是离子通道