Synergists and their M i x t u r e s in W o Vegetable O i l s By M. M. A h m a d , S. A 1 -H a k i m and A. A . Y S h e h a t a *Tertiary butylhydroquinone (TBHQ, hydroquinone (HQ,propylgallate (PG), butylated hydroxytoluene ( B W and butylated hydroxyanisole (BHA) had much higher antioxidant activity in crude safflower oil than in a commercial brand vegetable oil (Bint oil). The following active oxygen (AOM, hours at 97.80 C) and storage stability (days at 45O C) values for each antioxidant in safflower oil were; (27.9,105.0), (21.2,44.8), (15.3,45.5), (9.8, 36.8) and (7.9.33.5) respectively compared with (6.8.31.5) for the control. Ascorbylpalmitate (AP),ascorbic acid (AA) and citric acid (CA) were found to improve the AOM stability of both oils. The same values in Bint oil were: (9.0,34.3), (9.0,28.3), (9.4,41.0), (7.3,28.5) and (6.2,2.5) respectively compared with (5.3.23.3) for the control. Ascorbyl palmitate (AP), ascorbic acid (AA) and citric acid (CA) were found to improve the AOM stability of both oils.AP was moreeffectiveandCAleasteffectiveinsaffloweroi1,whereasthe reverse was true in Bint oil. The five antioxidants were individually blended with the three synergists (0.01Vo of each) and the 15 combinations added to each oil and compared with the antioxidant controls at 0.02%. Safflower oil stability was greaterwithpureTBHQHQandPG than with any of the synergist mixtures whereas the BHA, BHT-synergist mixtures were found equal or superior to that treated with BHA or BHT alone. Bint oil treated with CA-TBHQor CA-HQmixtures showed improved stability compared tooils treated with these antioxidants alone. However, the AOM method alone suggested CA-PG,CA-BHA andCA-BHTmixturesimproved thestabilitycompared totheoil-antioxidantcontrols.Che1ationofmetalsbyCAwasassumedto be the primary cause of this synergism, whereas AP and AA behaved more like weak antioxidants. FETTE . SEIFEN . ANSTRICHMI 1 11:l. a.J+g NK 12 1 Y M

Of 27 amino acids studied, most had some antioxidant activity when added in aqueous solution to either safflower oil or a mixture of sunflower and cottonseed oil (active oxygen and storage methods). Cysteine-HCl, glutamic acid-HC1 (in the mixture), and glutamic acid-HCl (in safflower oil) behaved as prooxidants. When added as a solid, most amino acids were ineffective. The protection factors of these amino acids were less than 1.3 in safflower oil with methionine, proline, lysine and cysteine providing the highest activity. In the oil mixture (which had a higher metal content) lysine, arginine, glutamic acid, methionine, and hydroxyproline were antioxidant with protection factors of up to 1.85. Chelation of metals by amino acids was presumably responsible for the antioxidant activity. The increase in cysteine concentration up to 1% has more than doubled the protection factor in Bint oil (compared with the 0.01% level), whereas with some other amino acids the increase was either small or slight.

The quality of rendered leaf fat from mature breeder fowl which contained varying amounts of tocopherol due to in vivo dietary supplementation or due to direct in vitro addition was investigated. Treatments were dietary supplementation with d-alpha-tocopheryl acetate at levels of 0, 0.025, 0.050, 0.075 and 0.100% (0 to 1360 I.U./kg. feed) for 3 weeks pre-slaughter and in vitro d-alpha-tocopherol addition of 0, 10.74, 21.48, 32.22 and 42.96 (xg./ml. of rendered fat (0 to 6.4 I.U./100 ml. fat) of fowl fed 3 weeks on a diet containing no tocopherol supplementation. Parameters used to estimate fat quality included AOM stability time, free fatty acid content, initial peroxide value, and moisture and volatile matter content. Tocopherol content of the rendered fat was also determined.Fat tocopherol content was found to be significantly related to AOM stability time (r = 0.93, P < 0.01). The relationships of amount of in vivo or in vitro supplementation to the amount of tocopherol recovered in the fat and to AOM stability time were linear, positive and highly significant. The in vivo and in vitro methods of supplementation had significantly (P < 0.01) different effects on fat tocopherol content. Significantly less tocopherol was necessary to be present in the fat for in vivo vs. in vitro supplementation to obtain similar AOM stability times. However, in vivo supplementation required over 400 times the amount of tocopherol compared to in vitro supplementation to reach fat tocopherol levels where AOM stability times were similar. From these results in vitro addition of tocopherol appears to be the more economical and efficient procedure to improve quality and stability of rendered fowl fat.