Studies of niacin and acrylamide during processing of instant Asian noodles

Instant noodles are a popular food consumed around the world and therefore their significance nutritionally, and to health and wellbeing, are increasingly important issues. Recent research has shown that a number of vitamins are rapidly lost during noodle processing. Accordingly, the first aim of this study has been to extend the previous work to a study of niacin retention in noodles. The second objective was to investigate the possible formation of the toxin acrylamide during noodle processing. The first steps have been to evaluate, adapt and validate analytical procedures for niacin and acrylamide in instant noodles. The resultant methods were then applied to noodle samples particularly to those prepared under controlled conditions in the laboratory. <br><br>For instant noodles, niacin has been analysed using a sequential treatment with acid and alkaline solutions followed by solid phase extraction for cleanup of niacin from the complex food matrix, prior to measurement by HPLC with UV detection. The results demonstrated good recoveries as well as symmetrical peak shape and the procedure was found to be suitable for analysis of instant noodle samples. Wheat flour was not a good source of the vitamin so the effectiveness of fortification was evaluated. No significant losses occurred at any of the steps during processing and instant noodles were found to be a suitable vehicle for fortification with no requirement to protect niacin used as a fortificant.<br><br>Since the first report of the toxin acrylamide in foods in 2002, there have been various studies on its formation, particularly in potato products. As little is known of acrylamide in Asian instant noodles, this study was designed to firstly establish reliable, sensitive methods for the extraction and analysis of acrylamide for these products. The approach involved derivatisation followed by gas chromatography with electron capture detection in conjunction with the standard addition method as well as use of an internal standard. This procedure has been validated and applied to various samples including commercial instant noodles. Typical levels of acrylamide in the noodles were approximately 60 µg per kg and within the context of the popularity of these products, it is therefore likely that they contribute significantly to the overall intake of acrylamide for consumers in many countries. <br><br>Further investigations have focused on the impact of processing conditions on acrylamide formation in noodles. Temperature and time of frying, as well as pH of the product formulation were all found to significantly influence acrylamide contents. Another approach found to be effective for reducing acrylamide formation is the incorporation of a microbial asparaginase. Suitable dosages of this enzyme and treatment conditions have been investigated and a series of effective strategies are now recommended to minimise the formation of acrylamide during processing of Asian instant noodles.<br>