Temperature-dependent decay of wheat germ agglutinin activity and its implications for food processing and analysis

A recently-described immunoenzymatic (ELISA) method for the quantitative determination of biologically-active wheat germ agglutinin (WGA) in unknown samples has been applied to measure the concentration of active WGA in raw and cooked wheat-derived foodstuffs. The method exploits the binding specificity of WGA to ovalbumin as a first step followed by identification of bound lectin with polyclonal antibodies. Purified WGA was used to obtain calibration curves. Detectable amounts of WGA were found in raw foodstuffs and wheat flours, whilst variable amounts of agglutinin were found in wholemeal pasta probably as a consequence of thermal inactivation during food processing. The thermal gradient gel electrophoresis (TGGE) technique was therefore applied to analyse the thermal stability of WGA. The biological activity of WGA decreased as a function of heating temperatures and time of exposure to thermal treatment in an S-shaped fashion with an inflection point around 65 \ub0C. As a consequence, WGA might represent a biochemical \u201cindicator\u201d allowing one to determine the thermal treatment undergone by wheat-derived foods during processing

Effects of dietary wheat germ deprivation on the immune system in wistars rats: a pilot study

Bioactive molecules that can gain access to body tissues through the gastrointestinal tract may interact with immune regulatory circuits and effector functions. Among these are plant lectins, such as wheat germ (WG) agglutinin, which constitute common components of the human diet and target the immune system on a daily basis. Dietary bioactive molecules might be considered as immunomodulatory signals. To investigate the possible effects on the immune system of the long-term absence of such signals, two groups of rats were fed on a diet containing or deprived of WG. The WG-deprived diet induced a state of functional unresponsiveness in lymphocytes from primary and secondary lymphoid organs, as evaluated by in vitro stimulation with T cell mitogen phytohemoagglutinin (PHA) and B cell mitogen lypopolysaccarides (LPS). The unresponsive state of the immune cells could be reversed by injection of antigen emulsified in oil with inactivated mycobacteria (complete Freund's adjuvant, CFA) Dietary signals can thus interact with the immune system possibly influencing its shaping during ontogenesis