. Conclusions
In this paper an aqueous extraction procedure is proposed to
obtain highly functional extracts from orange peels. Experimental
design and response surface methodology have been used to optimize
all the operational conditions with the aim of obtaining extracts
with high concentrations of phenolic compounds, high total antioxidant
and antimicrobial activity against E. coli and L. innocua. We have
found the most effective extracts were obtained after drying the orange
peels at 145.3 C during 701 min, and when the extracts were
obtained at 57 C during 71min. Finally, the extracts were successfully
applied to apple juice decreasing the browning at the same rate as
synthetic antioxidant and reducing to non-detectable levels the
presence of E. coli and L. innocua in inoculated juices when the extract
concentration was over 0.5e1%. Beside the positive effects due to the
designed extracts, it has to be considered the synergic contribution of
the organic acid of the media.