Effects of different ovens and enzymes on quality parameters of bread

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Food Engineering, Turkey

Approval Date: 2003




The main objective of the study was to determine the effects of enzymes on quality of breads baked in halogen lamp-microwave combination, microwave and conventional oven. It was also aimed to determine the optimum processing conditions in these ovens. In the first part of the study, as independent variables, baking time, baking temperature for conventional oven; microwave power for microwave oven and microwave power and halogen power for combination oven was used. Weight loss, specific volume, firmness and color of the breads were measured during the study. The optimum baking conditions were determined as 13 min at 200°C in conventional oven, 0.75 min at 100% power in microwave oven, 10 min at 60% power in halogen lamp oven, and 3 min at 30% microwave power and 70% halogen lamp power in halogen lamp-microwave combination oven. In the case of combination oven, specific volume and color values of breads were comparable with the conventionally baked breads but weight loss and firmness of them were still higher. The effects of different enzymes (a-amylase, xylanase, lipase & protease) were studied to reduce the quality problems of breads baked in microwave and halogen lamp-microwave combination oven. The optimum baking conditions determined for each type of oven in the first part of the study were used in the investigation of the functions of enzymes on bread quality during baking and staling. As a control, no enzyme added breads baked at 200°C for 13 min in conventional oven were used. All the enzymes were found to be effective in reducing initial firmness and increasing specific volume of breads baked in microwave and halogen lamp-microwave combination ovens. However, in conventional baking, the effects of enzymes on crumb firmness were seen mostly during storage. The usage of enzyme protease in the bread formulation resulted in breads with higher volume and darker