00000ctm a22000003a 4500 UP-99796217610259195 Buklod 20120324103551.0 a r |||| u| ta 120324s2011 xx d r |||| u| (iLib)UPD-00183810554 DCHE eng LG 993.5 2011 F66 C67 Cortez, Izza Patricia Q. The effects of common processing methods on the antioxidant activity of Philippine sweet potato (Ipomea batatas) varieties Izza Patricia Cortez ; Ma. Leonora dL Francisco, adviser. Quezon City UP College of Home Economics 2011. x, 115 leaves Thesis (BSFT)--University of the Philippines Diliman. ABSTRACT Total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, chelating activity, and total antioxidant activity (TAA) of fresh, baked, boiled, and fried Philippine sweet potatoes (Emitlog and VSP 6) were measured. Processing was found to significantly (p<0.05) affect the phenolic content and antioxidant capacity of both varieties. Emitlog had higher phenolic content(Emitlog= 47.84 - 89.6 mg GAE/100g sample; VSP 6= 25.86 - 46.37 mg GAE/100g sample), DPPH radical scavenging activity (EC50 0.54 - 1.49; EC50 2.64 -14.62), reducing power (EC50 21.92 - 49.73; EC50 65.78 - 149.58), chelating activity (EC50 13.65 - 26.54; EC50 15.59 - 22.82), and total antioxidant activity (10.57% - 76.06%; 22.92% - 33.25%) than VSP 6 for all treatments. Boiled and fried samples had greater phenolics and antioxidant activity than those that were baked and unprocessed. Significant (p<0.05) negative correlation exists between DPPH scavenging activity and reducing power (R = -0.977), and chelating activity and TAA (R = -0.965) for Emitlog. No significant correlation was observed between treatments for VSP 6. Sweet potatoes Philippines Processing. Francisco, Ma. Leonora dL. Fi Thesis UPD DCHE LG 993.5 2011 F66 C67 Thesis