In foods, the appearance is a primary criterion in making purchasing decisions [1]. Appearance is utilized throughout the production-storage-marketing-utilization chain as the primary means of judging the quality of individual units of product [2]. The appearance of unities of products is evaluated by considering their size, shape, form, color, freshness condition, and finally the absence of visual defects [3]. Especially, color is an important sensorial attribute to provide the basic quality information for human perception and has close association with quality factors such as freshness, maturity, variety and desirability, and food safety, and therefore is an important grading factor for most food products [4]. Color is used as an indicator of quality in many applications.