Pulsed-field gradient NMR (PFG-NMR) is being widely applied to probe living tissues and biological cells structure for measurement of thermodynamic binding constants, membrane permeability and rate of transmembrane exchange processes. Water movements in biological systems and food matrices are important in the engineering aspect such as quality manipulation in food processing. The measurement of diffusion properties of water molecules in food systems is now possible using PFG-NMR, and the hydration properties and hydrodynamic properties of food materials can be accurately evaluated by this method.

Pulsed-field gradient NMR (PFG -NMR) is widely applied to probe living tissues and biological cells structure for measuring thermodynamic binding constants, membrane permeability and rates of transmembrane exchange processes. Water movements in biological systems and food matrices are important in the engineering aspect such as quality manipulation in food processing. The measurement of diffusion properties of water molecules in food systems is now possible using PFG -NMR, and the hydration properties and hydrodynamic properties of food materials can be accurately evaluated by this method. In this paper, we measured the diffusion behavior of water in protein matrix, Tofu, and the membrane permeability in biological cell such as chlorella, yeast and human red blood cell non-invasively by PFG-NMR.

When a starchy food such as a rice grain or a strand of noodle is boiled, a high moisture region is generated at the surface spreading inward, producing a low moisture core. The characteristic features of the change of moisture profile were recently observed by nuclear magnetic resonance imaging (MRI). However, the profile cannot be described by any existing mathematical model based on the principle that water molecules are driven by the gradient of moisture content. In this paper, a new mathematical model is proposed using a new concept, water demand (WD). In this model, migration of water is driven by the gradient of WD, which is defined as the difference between the ceiling moisture content and the existing moisture content. This model is demonstrated to have a potential to describe the characteristic features of the change of moisture profile in starchy food during boiling.

Locomotor activity and food and water consumption are potentially indices of post-operative pain in laboratory rodents, but it is important to establish whether these variables are directly affected by opioid analgesics or by halothane anaesthesia in normal rats. The effects of three opioids, buprenorphine, nalbuphine and butorphanol administered alone or following halothane anaesthesia, were studied in groups of normal non-operated adult Wistar rats. All 3 analgesics affected food intake and activity levels, but had little or no effect on water intake. Buprenorphine caused a significant elevation of activity levels and a reduction in food intake at clinical doses (0·01 and 0·05 mg/kg s/c). Nalbuphine (0·5, 1 and 2 mg/kg s/c) caused a reduction in food intake but had a smaller stimulatory effect on locomotion. Butorphanol (0·4 mg/kg s/c) caused a reduction in food intake and elevation in activity. These results suggest that water consumption is likely to be a more reliable variable to use when assessing post-operative pain and the efficacy of analgesics in rats.