Efect of Temperature and Duration of Thermal Process on the Occurrence and Stability of Acrylamide in Chili Powder

Abstract

       Chili powder is an agricultural commodity, which is commonly consumed, produced and used as a key ingredient in many food products. During 2007-2008, risk assessment of acrylamide (AA) in foods for Thais was conducted and found that chili powder had the highest mean levels of AA among foods subjected to the study and accounted for a third of dietary exposure to the AA, coming after potato crisps and potato starch. Consequently, to reduce acrylamide formation in chili powder, the efect of temperature and duration in chili powder processing was then investigated to obtain the processing condition with low acrylamide formation. Studies on the stability of acrylamide in chili powder was also examined to observe the trend in stability of AA in chili powder during storage at room temperature. Samples used in this study are Capsicum annuum Linn. The levels of acrylamide in fresh chili, dried chili (fresh chili heated at 60°C 9 h.) and chili powder (dried chili heated at 90, 110 and 130°C for various times) were analyzed by liquid chromatograph/triple quadrupole mass spectrometer (LC/MS-MS). The results showed that AA was not detected in both fresh and dried chili. Acrylamide was found at 0.07 - 6.48, 1.75 - 8.65 and 14.7 - 18.1 mg/kg in chili powder heated at 90°C for 20 - 300 min, 110°C for 20 -180 min and 130°C for 20 - 180 min, respectively. This study indicated that the main factor causing the occurrence of acrylamide in chili powder was temperature used in process. Thus, low-temperature long-time process should be applied instead of high-temperature short-time process to reduce levels of acrylamide in chili powder. Acrylamide formed in chili powder is not stable. The acrylamide in chili decreases exponentially, rapidly decreasing at the beginning of the process, and then dropping slowly until being constant.