Preparation and characterization of carboxymethyl-nata and its postharvest use in preserving the shelf-life of bell peppers (Capsicum annuum L.)

Date

4-2005

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Veronica C. Sabularse

Abstract

MONTALBO, MARY NIZZA D. University of the Philippines Los Bafios. April 2005. Preparation and Characterization of Carboxymethyl-nata and Its Postharvest Use in Preserving the Shelf-life of Bell Peppers (Capsicum annuum L.).

Major Adviser: Dr. Veronica C. Sabularse

Caboxymethyl-nata (CMN) was prepared by pre-treatment of the cellulose with isopropyl alcohol, followed by two cycles of mercerization and etherification. The first cycle product (CMN l) appeared as fluffy, white solids with a moisture content of 6.05%, degree of substitution (DS) of 0.36, degree of polymerization (DP) of 303.88, average molecular weight (MW) of 4.923 x 10° and a solubility in water of 11.77%. The second cycle product (CMN2) was a white powder with a moisture content of 8.74%, DS of 0.61 DP of 390.22, average MW of 6.322 x 10° and a solubility in water of 40.37%. CMN2 was soluble in concentrated inorganic acids, partially soluble in dilute inorganic acids, alkali and organic acid, soluble in 10% NaOH and insoluble in organic solvents. Results of proximate analysis and infrared analysis of raw nata and CMN2 indicated conversion of the nata cellulose to carboxymethyl-nata. Coating formulations containing 1% and 2% CMN2 were prepared and coated on bell peppers to assess the ability of CMN to extend the shelf-life of the fruits. The 2% CMN coating retarded color change and maintained firmness of bell peppers, whereas the 1% CMN coating decreased shriveling of bell peppers. Both CMN coatings were found to decrease disease incidence of the fruits but did not significantly reduce the percentage weight loss. Significant differences in TSS, TA and pH values of the 1% and 2% CMN relative to control and blank coated fruits showed that both CMN coatings could retard fruit ripening. The antioxidant activity (AOA) and total phenolic content (TPC) of bell peppers determined at day 0 and 15 of storage showed an increase in values with time. Lower values of AOA and TPC were observed in 2% and 1% CMN coated fruits, than in the control and blank.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2005 C4 M67

Document Type

Thesis

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