Respiration rate and ethylene produ

Respiration rate and ethylene production are important fundamental processes in plant tissues. Clearly,the rates of O2 consumption and CO₂ production are important in packaged products ( such as most HPP products ) since, for excessively low o2 concentration will lead to anaerobic responses and off-flavours. Thus select appropriate packaging and to understand the basic mechanisms of HPP treatment on intact tissues,it is important to understand the effects of HPP on the respiration rate of the fruit. Ethylene is also important because of its control of ripening and senescent responses in fruit tissues and in fresh-cut products. Despite this, there is a dearth of research into the effects of HPP treatment on respiration and ethylene production rates of plant materials. Preliminary work by eggleston and tanner (2005) showed a reduction rate of carrot sticks treated with HPP at 600 MPa for 2 min,with a 10-fold drop in CO₂ production. The only published study on fruit responses to HPP was by Baba,como,ohtsubo,ikeda,and lizada (1999), who showed that in whole mume fruit,HPP could reduce both CO₂ and ethylene production (reductions by=2-fold and 5-fold,respectively). However, they used a maximum pressure of only 200 MPa.