# Phenolic Profiling of Five Different Australian Grown Apples
## 3 Results and Discussion
### Antioxidant Activities (DPPH, FRAP, ABTS and TAC)  
The antioxidant potential of five varieties of apple samples were estimated by four assays including DPPH, FRAP, ABTS and TAC assays, and the antioxidant activities were expressed in ascorbic acid (AAE) per gram (fw) as mentioned in Table 1. \begin{table}
\begin{tabular}{c c c c c} \hline
**Antioxidant Assays** & **Royal Gala** & **Pink Lady** & **Red Delicious** & **Fuji** & **Smitten** \\ \hline TPC (mg GAE/g) & 104.21 \(\pm\) 3.10 b & 94.23 \(\pm\) 2.24 c & 121.78 \(\pm\) 3.45 a & 102.26 \(\pm\) 2.14 b & 83.98 \(\pm\) 1.05 d \\ TFC (mg QE/g) & 93.73 \(\pm\) 1.10 b & 81.23 \(\pm\) 2.25 d & 101.23 \(\pm\) 3.75 a & 87.26 \(\pm\) 1.54 c & 72.19 \(\pm\) 1.75 e \\ TTC (mg CE/g) & 3.45 \(\pm\) 0.09 d & 4.25 \(\pm\) 0.01 b & 2.17 \(\pm\) 0.05 e & 4.65 \(\pm\) 0.03 a & 3.95 \(\pm\) 0.08 c \\ DPPH (mag AAE/g) & 3.39 \(\pm\) 0.05 b & 2.56 \(\pm\) 0.03 c & 3.53 \(\pm\) 0.07 a & 1.98 \(\pm\) 0.01 d & 1.17 \(\pm\) 0.02 e \\ FRAP (mg AAE/g) & 4.12 \(\pm\) 0.07 b & 3.15 \(\pm\) 0.12 c & 4.42 \(\pm\) 0.01 a & 2.12 \(\pm\) 0.04 d & 2.15 \(\pm\) 0.02 d \\ ABTS (mg AAE/g) & 3.22 \(\pm\) 0.12 a & 2.94 \(\pm\) 0.01 b & 3.24 \(\pm\) 0.09 a & 1.87 \(\pm\) 0.10 c & 1.49 \(\pm\) 0.09 d \\ TAC (mg AAE/g) & 2.68 \(\pm\) 0.09 b & 2.19 \(\pm\) 0.11 c & 3.12 \(\pm\) 0.01 a & 1.96 \(\pm\) 0.08 d & 1.32 \(\pm\) 0.01 e \\ \hline \end{tabular} All values are expressed as the mean \(\pm\) SD and performed in triplicates. Different letters (a, b, c, d, e) within the same column are significantly different (\(p\) < 0.05) from each other. The five varieties of apples are reported based on fresh weight. CE (catch equivalents), QE (quercetin equivalents), GAE (gallic acid equivalents), AAE (ascorbic acid equivalents), TPC (total flavonoids content), TPC (total phenolic content), TTC (total tannins content), FRAP (ferric reducing ability of plasma), DPPH (2,2’-diphenyl-1-picrylhydrazyl), TAC (total antioxidant capacity), ABTS (2,2’-azino-bis-3-ethylbenzothazoline-6-sulfonic acid).  
\end{table} 
Table 1: Phenolic content and antioxidant potential in five varieties of apples. In the DPPH assay, the free radical scavenging activity is determined which is attributed to the phenolic compounds [40]. The apple varieties in the current study varied from 1.17 to 3.53 mg AAE/g. Red Delicious had the highest antioxidant potential followed by Royal Gala, Pink Lady, Fuji and Smitten. Previous studies reported that antioxidant potential for over ten varieties of apples ranged from 0.26 to 9.30 mg AAE/g [41; 42]. The values of Fuji and Red Delicious apples are slightly higher than ours which might be because of the cultivar, location, maturity and storage of apples which may change the concentration of antioxidant potential [43]. FRAP assay can provide comprehensive information about the antioxidant activities of five varieties of apples since various antioxidant assays can help us to understand the antioxidant properties of apples better [44]. In FRAP assay, the electron transfer method was used to measure the capacity to reduce Fe\({}^{3+}\) to Fe\({}^{2+}\)[20]. The FRAP values were significantly different (\(p<0.05\)) from 2.12 \(\pm\) 0.04 mg AAE/g to 4.42 \(\pm\) 0.01 mg AAE/g among the apple varieties. The highest FRAP capacity was recorded in Red Delicious, followed by Royal Gala, Pink Lady, Fuji, and Smitten. In the ABTS assay, the antiradical scavenging activities were determined based of the hydrogen atom donating tendency of polyphenols [40]. The highest antioxidant ability was demonstrated in the order of Red Delicious \(>\) Royal Gala \(>\) Pink Lady \(>\) Fuji \(>\) Smitten. Upon comparison with the previous studies' Royal Gala and Fuji showed higher antioxidant ability than the previous reported values [41; 42]. The reason might be because of the cultivar, location, maturity and storage of apples which may change the concentration of antioxidant potential [43]. In the TAC assay, the mechanism very similar to FRAP where reduction of molybdenum (VI) to molybdenum (V) in the presence of phenolics.