Degradation, early detection

In former experiments (5) we have shown that chemical analysis for Amadori compounds (mainly consisting of fructose-glutamic acid) and isovaleralde-hyde, formed by Strecker degradation of the amino acids leucine and isoleucine, can be used for an early detection of undesirable quality changes caused by the Maillard reaction. In order to demonstrate the usefulness of these compounds as indicator substances for quality improvement of dried products, we performed drying experiments with carrots as an example of plant products. 

As a monitoring tool early detection of degradation in the accuracy of an inferential and disabling it before its poor performance does any real harm. However it needs to be used with care. Firstly, if our controller is successful, it will reduce a actual- Our performance parameter will then fall, misleadingly indicating that the performance of the inferential has degraded. To avoid this we choose a constant value for ffactuab equal to the variation before the controller was commissioned. The second issue is that we have to use a number of historical values to calculate a actual usually 30. Thus, even if a problem with the inferential is resolved, the performance index will indicate a problem until 30 more laboratory results are taken. While we can reduce the number of historical values used, a better approach would be to treat as outliers the occasion(s) where the inferential is now known to have failed and remove them from the calculation of the index. 

Lipid oxidation has been proposed as the vehicle for manifestation of injury and loss of quality in food by physiological stresses such as chilling injury, senescence and dehydration. The objective of this chapter is to review how localized degradation of antioxidants has been used as a marker for early detection of lipid oxidation as well as in defining the mechanism of oxidative challenge. 

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