A complex approach to assessing properties of aerated agar-fructose gels: Application of acoustic emission technique. (June 2019)

• Record Type: Journal Article
• Authors: Jakubczyk, Ewa; Gondek, Ewa; Kamińska-Dwórznicka, Anna; Samborska, Katarzyna; Wiktor, Artur; Królikowski, Krzysztof
• Is Part Of: Food hydrocolloids. Volume 91(2019)
• Page Start: 66
• Page End: 75
• Publication Date: 2019-06
• Subjects: Acoustic emission -- Mechanical properties -- Texture -- Structure -- Aeration -- Gel; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2019.01.013
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: The aim of this work was to characterise aerated gels and evaluate the possibility of applying the acoustic emission (AE) method to determine the texture of foamed products. The model system was based on aerated agar-fructose gel. The effect of different whipping times on mechanical and acoustic properties was determined. The material was aerated for 1, 2, 3, 4, 5, 8, 10 and 15 min. The measurement of acoustic emission was carried out while compressing samples. Acoustic emission was registered in the range 0.1–18 kHz using a piezoelectric accelerometer. The density and selected mechanical and textural parameters (fracture force and area, force at strain of 20%, Young modulus) decreased with whipping time. The size of bubbles decreased during aeration of the sample up to 5 min. Further whipping caused an increase and afterwards a decrease of air bubble diameter after 8 and 15 min of aeration, respectively. The porous structure of agar-fructose gels had a significant effect on acoustic emission of the gel system. Damage to pores during compression may lead to emission of an acoustic signal. The more acoustic events and the higher acoustic energy emitted during deformation of the aerated gel indicated that more small bubbles were deformed during compression. Graphical abstract: Image 1 Highlights: Acoustic and mechanical tests were used to evaluate the properties of aerated gels. The presence of bubbles affected the structure and acoustic properties of gels. The decrease of bubble size caused a decrease of hardness. Acoustic emission was a sensitive method to determine texture of foamed gel.