Document Type

Thesis - Open Access

Award Date

2020

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Sergio Martinez-Monteagud

Keywords

Emulsions, Rheology, Soy lecithin, Stabilizer, Storage, Ultrasound

Abstract

The ability of high intensity ultrasound to produce stable emulsions without the addition of surfactant was evaluated in a dairy-based formulation. The formulation consisted of protein (4.33 ± 0.05%, whey protein concentrates (WPC80), carbohydrates (21.52 ± 0.75%, sucrose and maltodextrin), oil (2.90 ± 0.05%, soybean oil), and surfactant (0-.05%). Pre-emulsions formulated with either 0, 0.025, and 0.05% of soy lecithin were treated for 5 min at an acoustic intensity of either 42.58 ± 2.98, 56.83 ± 3.01, or 70.48 ± 2.97 W cm-2. The stability of the emulsions was evaluated through particle size, dynamic rheology, gel electrophoresis, and microstructure. In general, the particle size decreased with the acoustic intensity (397 to 230 nm), regardless of the concentration of soy lecithin. Dynamic rheology (strain and frequency sweeps) showed an improved stability of the emulsions treated at 56.83 ± 3.01 and 70.48 ± 2.97 W cm-2 without the addition of soy lecithin, displaying a distinctive viscoelastic region and a behavior of weak gel. During 21 days of storage at 4°C, the particle size slightly increased (470-500 nm), while the mechanical spectra remained essentially unchanged. High intensity ultrasound offers opportunities for reducing surfactants in dairy-based formulations.

Library of Congress Subject Headings

Lecithin.
Emulsions.
Dairy products industry.
Soy proteins.

Format

application/pdf

Number of Pages

84

Publisher

South Dakota State University

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Rights Statement

In Copyright