Comparative Study on the Total Phenolic Content and Radical Scavenging Activity of Common Edible Vegetable Oils

Abstract

The study investigates the antioxidant potential of commonly used vegetable oils viz., coconut (CNO), sunflower (SFO), rice bran (RBO), groundnut (GNO), sesame (SESO) and mustard oil (MO), where the oils were extracted with methanol; and these methanolic extracts were used for the antioxidant studies. Fatty acid composition by gas chromatography, physicochemical parameters such as specific gravity, refractive index, acid value, iodine value and peroxide value were also analysed. Total phenolic content (TPC) and antioxidant activities of the oils (DPPH, ABTS, superoxide and nitric oxide radical scavenging assays) were evaluated. Phenolic compounds were identified by high-pressure liquid chromatography (HPLC). Percentage TPC was highest in groundnut oil with 3.09 mg/100 g oil followed by coconut oil, rice bran oil, mustard oil, sunflower oil and sesame oil with 1.8, 0.89, 0.56, 0.49 and 0.33 mg/100 g oil, respectively. The methanolic extracts of oils showed potential antioxidant activity in terms of super oxide and nitric oxide radical scavenging activity. PRACTICAL APPLICATIONSThe present study indicated that vegetable oils can contribute to the dietary intake of antioxidants, depending on the processing condition. This is the first study of its kind to investigate and compare the phenolic content by HPLC and also the radical scavenging activity (DPPH, ABTS, superoxide and nitric oxide) of different oils. It was observed that the unrefined oils posses better antioxidant activity than the refined oils, which imply the importance of optimizing and/or modifying the existing steps in the vegetable oil processing to retain the polyphenolic content in vegetable oil without compromising other physicochemical parameters. The study has brought out the importance of polyphenolic compounds in vegetable oil as radical scavenging agents that could be beneficial in the management of many degenerative diseases. This may provide vegetable oils a new dimension in health management other than its traditional uses.

Fatty acids and sterols composition, and antioxidant activity of oils extracted from plant seeds

“…In this case, the highest total phenolics content was determined in nutmeg oil followed by aniseed, coriander, caraway and white mustard oil. Janu et al (2014) reported that the content of phenolic compounds in unrefined mustard oil was 0.56 mg GAE/100 g oil. In turn, Ramadan and Mörsel (2004) analyzed various crude seed oils and determined the total phenolics content in coriander oil at 11 mg caffeic acid equivalents per kg oil equivalents.…”

Oxidative stability, thermal stability and acceptability of coconut oil flavored with essential oils from black pepper and ginger

“…MCFA's are important in human diet as they are reported to be inert source of energy that the human body finds it easier to metabolize and do not require energy for absorption, utilization and storage (Hiroyuki et al 2008). Phenolic compounds namely, ferulicacid, vanillic acid, syringicacid, gallocatechin gallate, p-coumaric acid, sinapic acid and cinnamic acid, were identified from the methanolic extract of CNO (Janu et al 2014;Marina et al 2009). …”

O tratamento térmico influencia as características físico-químicas e oxidativas do óleo de coco

“…Esse resultado demonstra que o processo de aquecimento do óleo leva ao consumo dos antioxidantes, com o objetivo de inibir a formação dos produtos da oxidação. (28) O consumo de alimentos preparados em óleos ou gorduras processados, contendo produtos oxidados pode trazer prejuízos à saúde. Esses produtos podem provocar ligações cruzadas nas lipoproteínas de baixa densidade, causando acúmulo de colesterol nos vasos sanguíneos.…”