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Food Science and Biotechnology
→ Food Science and Biotechnology 2019 ; 28(3): 741-749
The effect of ultrasound and freezing/thawing treatment on the physical properties of blueberries
Konrad W. Nowak1, Magdalena Zielinska1, Katarzyna M. Waszkielis1
1Department of Systems Engineering, Faculty of Technical Sciences, University of Warmia and Mazury in Olsztyn, Heweliusza 14, 10-719 Olsztyn, Poland
ABSTRACT
The aim of the study was to investigate the effect of ultrasound treatment and freezing/thawing on the physical properties of blueberries (Vaccinium corymbosum L.). Fruits were subjected to ultrasound treatment, mechanical freezing/thawing, and freezing/thawing with subsequent ultrasound treatment. Moisture, density, porosity, hardness, springiness, cohesiveness, chewiness, gumminess, and color of blueberries were analyzed. Ultrasound treatment and freezing/thawing significantly decreased particle density and increased porosity of blueberries (p<0.05). Ultrasound treatment and freezing/ thawing produced significantly softer, less chewy and gummy berries in relation to control sample (p<0.05). All techniques induced considerable changes in the color of blueberries. The results indicates that ultrasound treatment performed after freezing/thawing, didn’t exert any effect on the fruits in relation to freezing/thawing alone (p>0.05); however, it is an interesting technique for processing fresh blueberries and an alternative to freezing/thawing, when the preservation of product quality is a priority or when rapid textural damage is required before diffusion processes.
KEYWORD
Ultrasound treatment, Freezing, Texture properties, Color, Blueberries
Food Science and Biotechnology 2019 ; 28(3): 741-749
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