Degree

Doctor of Philosophy (PhD)

Department

School of Nutrition ad Food Sciences

Document Type

Dissertation

Abstract

Crustacean processing in Louisiana generates vast amounts of byproducts, including crawfish processing byproducts (CB), whose disposal can be problematic unless utilized alternatively. The objective of this investigation was to design and develop a delivery system (DS) containing extracted astaxanthin (AX) from CB using a novel combined ethanol flaxseed oil (FO) ultrasound-assisted extraction (UAE) method and evaluate its quality characteristics. Additionally, anticancer effects of AX were evaluated. Investigations consisted of three studies.

Proximate composition, oxidative stability, and antioxidant capacity of AX from CB extracted both conventionally and by UAE was determined. AX concentration conventionally extracted from CB (FOCAX) was 0.0919 mg g−1 of FO. The combined UAE ethanol FO extracted AX from CB (FOCAXUAE) was 1.9 mg g−1 of FO with antioxidant capacity (71.81±0.42) significantly greater than FOCAX (63.16±0.22). FOCAXUAE was selected for use in further studies.

A pectin gelatin DSs (PGDS) for controlled release of extracted AX was developed. Releasing profiles of several formulations containing high degrees of methylation (HMP) or low degrees of methylation (LMP) pectins were evaluated. The in vitro release study investigated release of AX in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). However, desired release characteristics were obtained with the addition of hydroxypropyl methylcellulose (HPMC). Swelling index of both HMP and LMP formulations with HPMC in SIF after 180 minutes were 126.46% and 90.61%, respectively. Other formulations failed to swell in SIF, with exposure to low pH SGF resulting in all formulations rapidly releasing FOCAXUAE.

Anticancer properties were considered. A control (sunflower lecithin and FO in DMEM, Dulbecco’s modified Eagles medium) in the ratio (0.0025:0.005:1) on the viability of MDA-MB-231 cell lines showed RCV (relative cell viability) of 79.37±0.87 % (RCV of 97.37±0.06%, normalized to DMEM alone). RCV of MDA-MB-231 cells treated with AX (3µM, 5µM, and 7 µM) had significantly decreased (46.31±0.81%, 42.2±0.65%, and 55.51±0.19%, respectively).

Cell densities decreased in some groups treated with AX, showing fewer cells with mesenchymal-like shapes, suggesting reversal of the epithelial-to-mesenchymal transition (EMT). This research indicates high amounts of AX extracted from CB by UAE has cytotoxic activity that could be incorporated into polymer-based DS.

Date

6-9-2020

Committee Chair

Sathivel, Subramaniam

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