**5. Conclusions**

During the production of blanched almonds, almond skins are generated as a waste by-product and commonly utilized as livestock feed or fertilizer. Like other waste produced during food processing, almonds skins (as well as skins from peanuts, grapes, and oranges) contain a variety of phytochemicals with a potential for development of nutraceuticals and functional foods [9]. A growing body of the literature has revealed that phytochemicals, including polyphenols and fiber in almond skins, display properties associated with health benefits, including antioxidant, anti-microbial, anti-viral, neuroprotective, photoprotective, and prebiotic activities [14,23–25,38–42]. Despite large inter-individual differences in metabolic changes, acute intake of almond skin extract increased plasma catechin, naringenin, GSH/GSSG ratio, and GPx activity at 2–3 h post-consumption. Further, the interaction of absorbed almond skin polyphenols with the in vitro addition of vitamin E unmasked the protection of the absorbed almond polyphenols on the ex vivo resistance of LDL to oxidation. In conclusion, polyphenolic constituents in blanched almond skins are capable of up-regulating antioxidant defense mechanisms and enhancing the resistance of LDL to oxidation. Thus, almond skins generated during the production of blanched almonds have the potential for use in the development of value-added ingredients and food products.

**Author Contributions:** C.-Y.O.C., P.E.M., and J.B.B. designed research and conducted research; C.-Y.O.C. analyzed the data and prepared the draft report. J.B.B. acquired funding. All authors reviewed, approved, and accept responsibility for the final manuscript.

**Funding:** Support was provided by the U.S. Department of Agriculture (USDA) Agricultural Research Service under Cooperative Agreement No. 58-1950-7-014 and The Almond Board of California. The contents of this publication do not necessarily reflect the views or policies of the USDA, nor does mention of trade names, commercial products or organizations imply endorsement by the U.S. government.

**Acknowledgments:** We would like to express our gratitude to the Almond Board of California for providing financial support and blanched almond skin powder for the study and to the volunteers for participating in the clinical trial.

**Conflicts of Interest:** The authors declare no conflict of interest.
