Preparation and characterization of carboxymethyl chitin from shrimp shell and its postharvest use in extending the shelf life of mango (Mangifera indica L.) fruits

Date

5-2010

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Veronica C. Sabularse

Abstract

Carboxymethyl chitin (CMChi) was prepared from chitin extracted from shrimp shell. Extraction of chitin from shrimp shells was done by decoloration using a hexane-isopropyl alcohol extraction solvent system, deproteination using 3% NaOH, and demineralization using 75.6 g/L acctic acid solution. The chitin extracted from shrimp shell was employed in the preparation of carboxymethyl chitin. Carboxymethyl chitin, on the other hand was prepared by a three eyele mercerization and etherification two process. Mercerization was carried out using 50% NaOH, followed by etherification using CICH;COO with a molar ratio of 1:7 (N- acetylglucosamine units - CICH,COO). In this study, CM Chi prepared appeared as light yellow- brown crystals with a molecular weight (MW) of 3.385 x 105 Da, a degree of polymerization of (DP) 1667, a degree of acetylation (DA) of 0.6642, and a degree of substitution (DS) of 0.7915. The CMChi prepared had a solubility in water of 80.13%. Results of the characterization tests and infrared analyses of chitin and CMChi confirmed the conversion of chitin to CMChi. Edible coating formulations using CMChi as base were prepared and their ability to extend the shelf life of mango fruits was determined. Also, in this study, the protein extracted from shrimp shell during the deproteination step was incorporated as an additive in the composite coating. Coating formulations containing 1% and 2% CMChi were prepared. Both 1% and 2% CMChi formulations were effective in minimizing disease incidence in mango fruits. Moreover, 2% CMChi + additives was more effective in retarding peel color change and maintaining the firmness in mango fruits. Meanwhile, 1% CMChi formulations were effective in minimizing weight loss and shriveling in mangoes. Lower pH, higher titratable acidity, lower total soluble solids (TSS), lower total and reducing sugars content, lower carotenoid content, higher pectin content were observed in retardation of fruit ripeness.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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