Effect of contact ultrasonic drying on drying kinetics and physicochemical properties of egg whites

Egg white (EW) is a nutrient-dense food ingredient with a variety of functional properties. However, the limited shelf-life, susceptibility to spoilage, and transportation costs associated with liquid EW have prompted the use of drying as an effective preservation method. While thermal drying is a commonly used food preservation technique, its drawback is that it can cause structural damage and thermal degradation in EW, thereby necessitating the exploration of alternative drying methods for heat-sensitive products. In this study, the use of a variable frequency contact ultrasonic drying (CUD) method to produce EW powders was explored, by comparing it with spray drying (SD), freeze-drying (FD), and hot air drying (HAD) methods. An air stream at a velocity of 5 m/s was used in CUD and HAD to remove moisture. The CUD dryer was equipped with a 20 kHz variable frequency generator/modulator and drying was performed at 3 sound amplitudes (0%, 40%, and 60%) and 2 temperatures (40℃ and 60℃). SD was done at an air inlet temperature of 160℃ with a feed rate of 5-6 ml/min. FD was performed at -40℃ and 0.2 mbar pressure for 48 hours. Compared to HAD, the CUD led to a 240% increase in effective moisture diffusivity, a 66-78% reduction in activation energy, and a 27% reduction in drying time. The CUD process affected the proteins. This is evident by a) increased β-turns and random coil structures, b) increased free sulfhydryl group content, and c) 24-35% reduction in enthalpies for the ovotransferrin and ovalbumin proteins even at 60℃ of drying temperature. When compared to FD, the EW dried by CUD at 40℃ resulted in a 67% higher foaming capacity, while the CUD samples at 60℃ exhibited 37% better foaming stability. The soluble protein content increased by 10-12% in the CUD samples as compared to HAD, and was also slightly higher than in the FD samples. The EW dried by CUD exhibited a brighter color with a browning index 26% lower than the HAD product. This study demonstrates that CUD drying is a promising method for the production of dried EW with improved quality and reduced drying time.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Food Science & Human Nutrition

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Mundada, Vedant Kishor

Contributors dc:contributor

• Feng, Hao
• Lee, Youngsoo
• Wang, Yi-Cheng

• Egg White
• Drying Kinetics
• Contact Ultrasound
• Protein
• Functional Properties.

Statement dc:rights

• Copyright 2023 Vedant Kishor Mundada

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/120579

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F120579