Date of Award

12-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Food, Nutrition, and Culinary Science

Advisor

Chen, Feng

Committee Member

Liu , Haibo

Committee Member

Wang , Xi

Abstract

ABSTRACT
Maya nut was investigated in term of its moisture, ash content, antioxidant activities, phenolic components by high pressure liquid chromatography-ultraviolet detector (HPLC-UV) and fatty acid composition by gas chromatography-flame ionization detector (GC-FID). The results showed that Maya nut was mainly composed of 55.06% linoleic acid (C18:2 n6), 27.2% palmitic acid (C16:0), 6.26% stearic acid (C18:0), 9.9% linolenic acid (C18:3 n3), and 3.36% Cis-11-Eicosenoic (C20:1). Maya nut possesses a higher content of polyunsaturated fatty acids (PUFAs) (linoleic and linolenic acid), but lower content of monounsaturated fatty acids (MUFAs) than canola oil and olive oil. The antioxidant capacities and total phenolic contents of the methanolic Maya nut extract and other commercially available nuts including walnut, almond, and peanut were determined and compared by three different in vitro antioxidative assays, i.e., DPPH * free radical scavenging assay, ferric reducing antioxidant potential (FRAP) assay, and ABTS free radical scavenging assay. The DPPH radical scavenging activity and ABTS·⁺ radical quenching activity of the Maya nut extract were 83.35% and 92.55%, respectively, which were higher than walnut, almond, peanut and commercial antioxidant BHT. In addition, FRAP value of the Maya nut extract was 8.08 mmol Fe2+ /100 g sample, which was higher than that of peanut and almond, but lower than that of walnut. The TPC of Maya nut was 24.67 mg of gallic acid equivalents per gram of sample, which were 3, 6, and 28 times higher than that of walnut, peanut, almond. Furthermore, free phenolic acids in the Maya nut were analyzed by HPLC. 3, 4-Hydroxybenzoic acid (45 mg/kg), gallic acid (27.06 mg/kg), vanillic acid (21.15 mg/kg), and caffeic acid (6.5 mg/kg) were found after the acidic hydrolysis. After the alkaline treatment and the second acidic hydrolysis, 3,4 hydroxybenzoic acid (342.2 mg/kg), vanillic acid (103.9 mg/kg), caffeic acid (17.1 mg/kg), p-coumaric acid (13.5 mg/kg), epicatechin (53 mg/kg), and sinapic acid (8.16 mg/kg) were detected. These results demonstrated that Maya nut is rich in bioactive phytophenolics that results in high antioxidant activities; therefore, Maya nut is suitable to be made into health-benefiting nutraceuticals.

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Food Science Commons

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