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    Effects of extrusion cooking conditions and chemical leavening agents on lysine loss as determined by furosine content in corn based extrudates
    (Academic Press Ltd- Elsevier Science Ltd, 2014) Masatcioglu, Tugrul M.; Ng, Perry K. W.; Koksel, Hamit
    The aim of this study was to investigate the effects of different variables on lysine loss as determined by furosine content in corn-based extrudates. Three formulations were prepared to study the effects of different chemical leavening agents, processing conditions (feed moisture content: 22,24 or 26%; exit die temperature: 110 or 150 degrees C), and extrusion cooking methods (with/without CO2 injection) on furosine formation. Furosine levels of extrudates from both extrusion methods decreased around 20% when feed moisture content was increased from 22% to 26%. Amadori compounds (precursor of furosine) are formed in the early stages of the Maillard reaction, and later they are converted to further products. Consequently, furosine contents of extrudates significantly decreased as exit die temperature increased from 110 to 150 degrees C Furosine contents of extrudates produced with sodium- and ammonium-bicarbonate at 150 degrees C exit die temperature significantly decreased, while the ones produced at 110 degrees C significantly increased. This may be due to accelerated formation of fructosyllysine at higher pH values followed by early degradation at 150 degrees C. The CO2 injection method did not have a significantly different effect on furosine content of extrudates than that produced by the conventional extrusion method, but had a positive effect on the physical properties of extrudates. (C) 2014 Elsevier Ltd. All rights reserved.
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    Effects of formulation and extrusion cooking conditions on furfural and hydroxymethylfurfural content
    (Academic Press Ltd- Elsevier Science Ltd, 2015) Masatcioglu, Tugrul M.; Ng, Perry K. W.; Koksel, Hamit
    The objective of this research was to investigate the effects of different ingredients (reducing sugars, leavening agents, citric acid), processing conditions (feed moisture content, exit die temperature), and extrusion cooking methods (with/without CO2 injection) on furfural and 5-hydroxymethylfurfural (HMF) formation in corn-based extrudates. The decrease in furfural levels was 16% upon addition of sodium-bicarbonate, while the increase was 12% upon addition of ammonium-bicarbonate for extrudates produced at 150 degrees C and feed moisture content of 22%. The furfural concentration of extrudates produced at 150 degrees C and feed moisture content of 22% without leavening agents was 810 mu g/100 g and increased to 11,901 mu g/100 g upon citric acid addition (about a 15-fold increase). Furthermore, both low feed moisture and high exit die temperature had promoting effects on furfural and HMF contents. The CO2 injection method did not have considerable effect on furfural and HMF levels of the extrudates; however, it positively affected the physical properties of extrudates. (C) 2015 Elsevier Ltd. All rights reserved.