Mitigation of Acrylamide Formation in Bakery Products By Using Asparaginase Enzyme

Abstract

Maillard reaction is a reaction that occurs as a result of the interaction of amino groups and carbonyl groups. It improves the characteristics of foods such as color, taste, smell and texture although it causes some undesirable effects such as losses in the nutritional value of food and the formation of thermal process contaminants including acrylamide. Acrylamide is a carcinogenic, genotoxic, and cytotoxic compound formed by the reaction of asparagine and carbonyl compounds such as reducing sugars. The presence of asparagine, the precursor of acrylamide, in bakery products in high amounts leads to the formation of high amounts of acrylamide during the baking process. The high consumption of bakery products in the diet makes the development of strategies to reduce acrylamide in bakery products essential. The expectation of enactment of legal regulations regarding the limitation of the amount of acrylamide in bakery products in the future reveals acrylamide as a problem that needs to be solved for the industry. Asparaginase enzyme, which is envisaged as a tool for acrylamide reduction strategy, stands out as a good option because it does not require any changes in heat treatment parameters and product formulations, preserves sensory properties, and does not have to be specified on the product label. Within the scope of this thesis, applications were made by using commercial asparaginase enzyme in high water content hard biscuits, low water content hard biscuits, soft biscuits, pretzel-like snacks, and wafers to reduce asparagine in the dough of these products and accordingly to restrict acrylamide formation. For this purpose, changes were made on enzyme dosage, enzyme application time, resting time and temperature, dough mixing speed and time, and in the order of addition of the recipe components during dough preparation. As a result of these applications, acrylamide formation was reduced by 96% in the high water content hard biscuit, in which 3000 ASNU/kg flour asparaginase dose was applied and baked after 15 min resting time. In soft biscuits, 54% reduction in acrylamide was achieved with the application of 5000 ASNU/kg flour asparaginase dose and changing mixing order. Asparaginase dose of 3000 ASNU/kg flour and then 15 min resting time applied to the pretzel-like snack limited the formation of acrylamide by 80% after baking. A significant reduction of acrylamide could not be achieved in low water hard biscuits. The correlation coefficients between asparagine and acrylamide in high water content hard biscuit, low water content hard biscuit, soft biscuit, and pretzel-like snack were determined as 0.74, 0.03, 0.64, and 0.91, respectively. It was revealed that there was a strong positive interrelation between asparagine and acrylamide content in all products except for low water content hard biscuits where the asparaginase was not active. In the wafer, only asparagine analysis was performed and with 1000 ASNU/kg flour enzyme treatment 97% asparagine reduction was achieved. It was determined that the potential acrylamide formation reduction would be high. When the effects of water activity and pH on the activity of asparaginase in the dough of bakery products were examined, water activity was found to be more effective than pH. Additionally, application of asparaginase was found to have no adverse effect on the product quality parameters such as surface color and spread ratio. As a result of this study, high rates of acrylamide reduction were achieved in bakery products by using the asparaginase enzyme. This strategy could be used as a guide for the food industry to reduce acrylamide in bakery products.