Affiliation:
1. Department of Food Engineering, Faculty of Engineering and Architecture, Necmettin Erbakan University, Koycegiz Campus, Konya, Turkey
2. Department of Chemistry, Faculty of Science, Karamanoğlu Mehmetbey University, Karaman, Turkey
Abstract
Research background. Utilization of wheat germ (WG) and wheat germ oil (WGO) is limited due to high enzymatic activity and unsaturated fatty acids and therefore stabilization techniques are needed to overcome this problem.
Experimental approach. In this study, the effects of stabilization methods (dry convective oven heating at 90 and 160 oC and microwave radiation under 180 W and 360 W output power, and steaming by autoclave) on both WG and WGO were evaluated.
Results and conclusions. Steaming caused the most dramatic changes on lipoxygenase, free fatty acids (FFA), DPPH radical scavenging activity, tocopherols and tocotrienols. The lowest peroxide values (PVs) were measured in oils of convectional heating (160 oC) and steaming treatments which were performed at temperatures above 100 oC. However, para-anisidine values (pAVs) of samples treated at higher temperatures were considerably greater than those of stabilized at lower temperatures. Oven heating at 160 oC was also one of the most effective treatments on inactivation of lipoxygenase coming after steaming. Steaming also induced a significant reduction in total tocopherols which was directly associated with the greater lost in β-tocopherol content. On the contrary γ- and δ-tocopherols and tocotrienol homologs were abundant with higher amounts in steam applied samples. α-Tocopherol and γ-tocotrienol were the most resistant isomers to stabilization processes.
Novelty and scientific contribution. This study shows that the high temperature oven heating method, which is widely used in the industry for thermal stabilization of wheat germ, does not provide an advantage in oxidative stability compared to steaming and microwave applications. Steaming delayed oxidation in germ, while further inhibiting lipoxygenase activity. Moreover, tocotrienols were more conservable. In industrial application, low power in microwave (180 W instead of 360 W), lower temperature in oven heating (90 instead of 160 oC) would be preferable.
Publisher
Faculty of Food Technology and Biotechnology - University of Zagreb
Subject
Industrial and Manufacturing Engineering,General Chemical Engineering,Food Science,Biotechnology
Cited by
6 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献