PROTECTIVE EFFECT OF AROEIRA (Schinus terebinthifolius Raddi) FRUIT AGAINST CHOLESTEROL TERMO-OXIDATION IN MODEL SYSTEMS CONTAINING SARDINE OIL (Sardinella brasiliensis)

Lipids degradation caused by thermo-oxidation leads to nutritional and sensorial losses in food, besides the formation of cholesterol oxidation products (COPs), which are recognized by their cytotoxic, mutagenic, and carcinogenic effects. Therefore, researches on natural sources of antioxidants to replace synthetic additives are of great importance. Thus, this study evaluated the protective effect of aroeira fruits (0.2% and 0.5%) against cholesterol oxidation in model systems containing sardine oil heated at 150 °C and 180 °C. In addition, the synthetic antioxidant BHT 0.01% (butylated hydroxytoluene) was also applied for comparison. The oil was obtained from dried sardines (Sardinella brasiliensis) by cold extraction, using a mixture of chloroform-methanol-water. Cholesterol and cholesterol oxides were extracted simultaneously by direct saponification and the identification and quantification were performed in a High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS). Unheated samples showed a cholesterol level of 553.04 ± 7.9 mg/100 g oil, however, heating led to cholesterol degradation and increased COPs content. The major COPs identified in heated samples were 7-ketocholesterol, 7β- and 7α-hydroxycholesterol. The total COPs level varied from 58.9 ± 0.26 µg/g (unheated samples) to 478.2 ± 0.14 µg/g and 577.5 ± 2.14 µg/g in control samples heated at 150 and 180 °C, respectively. However, the addition of both natural and synthetic antioxidants reduced cholesterol oxidation. The effectiveness of antioxidants addition decreased in the following order: BHT > aroeira fruits 0.5% > aroeira fruits 0.2%. After heating at 180 °C, protective effects of 15.51% and 23.22% were observed for aroeira fruits 0.2% and aroeira fruits 0.5%, respectively. Although BHT had a greater protective effect, it was used in the maximum concentration permitted by Brazilian legislation (0.01 %), demonstrating that aroeira fruit may be applied as natural antioxidant in order to reduce the use of synthetic additives.