Quality characteristics of lotus root (Nelumbo nucifera G.) snacks according to heat treatment methods and conditions

This work investigated the effects of various heating methods and conditions on the quality characteristics of lotus root (Nelumbo nucifera G.) snack. The lotus root snacks were processed using the following heating methods: oven heating (OV), microwave heating (MW), air frying (AF), and oil frying (FR). Twenty four samples were prepared based on the various temperatures and time durations used for heating. Based on the results of color and hardness analyses, OV (180℃, 9 min), MW (850 W, 8 min), AF (120℃, 10 min) and FR (180℃, 70 sec) were selected as appropriate conditions for producing the lotus root snacks. AF resulted in low carbohydrate content, crude fat content, and neural detergent fiber content and the highest moisture content. There were no significant differences in hardness among four methods. AF (120℃, 10 min) showed significantly higher L^* values, total phenolics contents, and 2,2-dipheny-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulphonic acid radical scavenging activity than other methods. In addition, water absorption and water solubility indexes were the lowest in AF. Therefore, AF (120℃, 10 min) was considered as an appropriate heating condition for the manufacturing of lotus root snacks.