Conclusions
In this study, hexane extraction of Osage orange fruit produced an
extract rich in osajin (42.9%) and pomiferin (30.0%). The antioxidant
activity of the extract (OOE) was examined in stripped SBO and FO at 0.1
wt.% during storage at 25 and 40 ℃ using PV, CDV and p -AV. The
overall antioxidant activity order was BHT ≈ OOE > RE
> Toco in SBO at 25 ℃
and 40 ℃. In contrast, the activity order was OOE ≥ BHT >
Toco > RE in FO at both temperatures, 25 ℃ and 40 ℃. The
activities of 0.05, 0.1 and 0.2% OOE in SBO were not very different
indicating that the protection of SBO from oxidation can be achieved at
a concentration of OOE as low as 0.05%. Unlike in SBO, the antioxidant
activity of OOE increased with increasing concentration from 0.05% to
0.2% in FO. Headspace volatile oxidation products were analyzed using
SPME combined with GC-MS. 0.1% OOE was effective in preventing the
formation of volatile oxidation products in SBO and FO. While all four
antioxidants had similar effects in SBO, 0.1% OOE prevented the
formation of volatile oxidation products better than 0.1% RE and
similar to 0.02% BHT and 0.1% Toco in FO.
Although it should be further
tested for safety before the actual use, the strong antioxidant activity
of OOE in SBO and FO found in this study indicates the high potential of
OOE as a natural antioxidant for edible oils and oil-containing food
products.