<prompt> n-3 PUFA is present in all except:Mustard oilCorn oilFish oilGroundnut oil  <response>: Groundnut oil Corn oil Various research papers on the net have clearly mentioned both the groundnut oil and corn oil are devoid of n-3 fatty acids. However Lippincott Biochemistry 3e p360 mentions that corn oil contains little amount of n-3 fatty acids. According to Park 19e p482, table 2, both Groundnut oil and Corn oil are rich in n-6 fatty acid Linoleic acid. n-3 fatty acids popularly referred to as co-3 fatty acids or omega-3 fatty acids are long-chain polyunsaturated fatty acids, with the first double bond beginning at the third carbon atom when counting form the methyl end of the fatty acid molecule. Impoant nutritionally essential n-3 fatty acids are: - a-linolenic acid ALA, - eicosapentaenoic acid EPA, and - docosahexaenoic acid DHA. n-6 fatty acids are long chain polyunsaturated fatty acids, with the first double bond beginning at the sixth carbon atom eg. Linoleic acid, the most impoant essential fatty acid. Both the n-3 a-linolenic acid and n-6 linoleic acid are essential fatty, acids which must be obtained from food. Park mentions that an ideal fat for good health is one which maintains a balance so as to give a ratio of PUFAsaturated fatty acids of 0.8-1.0 and linoleicalpha-linolenic n-6n3 of 5-10 in the total diet. Park gives a list of food rich in alpha linolenic acid n-3 fatty acid: wheat, bajra, blackgram, iobia, rajmah soyabean, green leafy vegetables, fenugreek methi mustard and fish. Flaxseed oil is one of the best sources of the essential fatty acids. It contains approximately 50-60 of the omega-3 essential fatty acid alpha-linolenic acid, and roughly 18-20 of the omega-6 essential fatty acid linoleic acid. Flaxseed oil is natures richest source of linolenic acid n-3 fatty acid. 