Nowadays, more and more people are having pets as members of their family. To the year of 2012, there are 78.2 million dogs and 86.4 million cats owned in the U.S according to the report of the Humane Society of the U.S. The pet food industry as a result has been prosperous, with an estimated market size of $21 billion in the year of 2013. However, there is a common problem for the industry - fat rancidification. Pet foods usually contain relatively high levels of fat, which, if not well protected, are prone to oxidation and generate unfavorable products including acids, ketones and aldehydes. The resulting small volatile molecules will not only lead to unpleasant flavors and odors, but also could be unsafe if accumulated at high concentrations. In order to better preserve the quality of foods, it is a common and necessary practice to add antioxidant preservatives, which can scavenge free radicals and hence prevent or slow down the oxidation of fats. Currently available antioxidants can be generally divided into two categories: synthetic and natural antioxidants. Commonly used synthetic antioxidants include butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA) and tert-butylhydroquinone (TBHQ) and ethoxyquin (ETQ). Synthetic antioxidants are advantageous because of their high efficiency and low cost; however, they are criticized for having potential safety issues [3-7]. The natural options such as tocopherols and ascorbic acid are recognized as safer but less effective and are much more expensive compared to their synthetic counterparts. In spite of higher price and lower efficiency, there is a great customer demand for natural antioxidant, which is perceived to be beneficial for pet’s health. Consequently, there is a need to develop an alternative natural antioxidant, which is effective, inexpensive and safe
