Antioxidant activities of lemon and mandarin peel extracts as natural preservatives in ghee (butter oil) stored at different storage temperatures

Using natural preservatives in ghee and fat-rich products has great economic importance as it can minimize adverse effects on human health and improve the marketing prospects of products. The present study aimed to use lemon (Citrus lemon L.) and mandarin (Citrus reticulata L.) peel extracts as natural preservatives instead of synthetic antioxidants of butylated hydroxyanisole (BHA) to retard the oxidation of ghee during accelerated storage at various temperatures. Antioxidant activities of lemon peel extracts (LPE), mandarin peel extracts (MPE) and BHA in ghee samples stored at different storage temperatures (T1: 5±2°C, T2: 25±2°C, T3: 60±2°C) were evaluated during the storage period (0, 20 and 40 days). The peroxide value (PV), free fatty acids (FFA), and antioxidant activity of the ghee samples were analyzed and compared with control sample (without additives). The PV and FFA content were significantly higher in the control sample than in the ghee samples treated with BHA, LPE, and MPE at all storage temperatures and during the storage period. All treatments led to a reduction in the PV and FFA content, but LPE had the most significant effect, followed by BHA and MPE, respectively. Antioxidant activity was evaluated by the 3-ethyl benzthiazoline-6-sulphonic acid (ABTS) assay; LPE had the highest antioxidant activity, followed by MPE. Compared to the control sample: BHA, LPE and MPE led to a higher reduction in the PV and FFA content of ghee samples at all storage temperatures and periods owing to their antioxidant activities. Results of incorporated samples showed that using LPE (0.1%) prevented the development of PV and FFA content of ghee samples less than using BHA (0.2%). The present study suggests that LPE (0.1%) could be used as a good natural antioxidant preservative to reduce oxidative deterioration of ghee and fat-rich products.