The effect of Ca2+ and cellular structure on apple firmness and acoustic emission

Abstract

This study presents the influence of calcium lactate treatment (0-6 %) and cellular composition on two mechanical attributes: firmness and total acoustic emission (AE) events registered in the puncture test of apple tissue. The experiment was performed on five apple cultivars stored for nine months in a normal or controlled atmosphere. The microstructure was characterized quantitatively on control samples by confocal scanning laser microscope followed by image analysis. The mean area and perimeter of detected objects, which were either cells or spaces, and estimated cell wall fraction were used for the characterization of the tissue microstructure. Treatment with increased Ca 2? concentration caused a significant increase in firmness and total AE events. The increase was more pronounced in the case of total AE events which better reflected an increase in brittleness of apple tissue than firmness parameter. The effect was particularly positive in the case of very soft apples (stored in a normal atmosphere) due to greater extent of de-esterification of homogalacturonan. Analysis of the results, together with a review of the literature, suggests that calcium importantly changes the cracking mode of tissue, from intercellular debonding to cell wall rupturing. Firmness and the total AE events significantly relate negatively to the object's size and positively to estimated cell wall fraction. A rough accordance of the number of split cells open across cell walls by puncture probe and the total AE events registered in the test, which was saturated in high Ca 2? concentrations, was noticed.

Structure influence on mechanical and acoustic properties of freeze‐dried gels obtained with the use of hydrocolloids

“…The amplitude of the brittle sound at any time is the function of the volume of the sound generated by a single cell, and the cell wall crack volume (Dacremont, ); it is proportional to the load at the time of energy release, and therefore it may be expected that cell walls resistance to compression has an impact on acoustic measurements due to the greater amount of energy released in the process (Cybulska et al ., ). One factor strongly affecting the acoustic performance of brittle/crunchy products is their microstructure (Luyten & Van Vliet, 2006).…”

“…Sounds generated during eating are important in crispy foodstuffs texture. The sound emitted by fresh fruit is a result of the rapid release of turgor pressure inside cells, and a sound wave is produced (Cybulska, Pieczywek, & Zdunek, ). Studies have shown that the combination of the acoustic analysis with mechanical testing and sensory evaluation ensures precise evaluation of the texture of dried apples (Marzec & Zadrożna, ).…”

Effect of Storage on Rheology of Water-Soluble, Chelate-Soluble and Diluted Alkali-Soluble Pectin in Carrot Cell Walls

“…Pectinolytic enzymes cause structural changes of pectins, which affect cell walls and overall tissue firmness during maturation and storage (Cybulska et al 2010). The enzymes are widely used in the food industry as clarification agents for fruit juices, coffee and tea fermentations (Cybulska et al 2012). In addition, pectinolytic enzymes are involved in maintaining a balanced ecosystem, decomposing organic material from plants (Jayani et al 2005;AlimardaniTheuil et al 2011).…”

Effect of Ca2+, Fe2+ and Mg2+ on rheological properties of new food matrix made of modified cell wall polysaccharides from apple

“…Contrary to iron and calcium addition, magnesium caused a decrease of viscosity of MPS with increasing concentration. Changes in viscosity of MPS in calcium hydroxide solutions are associated with the cross-linking ability of polysaccharides, especially low-methylated pectin chains with calcium cations (Cybulska et al, 2012;Fang et al, 2008;Fraeye et al, 2010;Kastner et al, 2012;Ralet et al, 2003;Ventura et al, 2013;Videcoq et al, 2011;Yang et al, 2013;Yapo & Koffi, 2013). A significant increase of viscosity in the case of the addition of iron lactate may be explained as an ability of divalent iron ions to interact with polysaccharides resulting in the forming of an intermolecular network similar to the structure of Ca 2+ -low-methylated pectin.…”

“…To ensure edibility as well, the delivery system might be made of cell walls from fruit and the desired thickening could be gathered from pectin gelling ability. Most of the previous studies on pectin extracted from fruit or vegetable cell walls have concerned the ability of interaction of low methoxyl pectin chains with calcium cations (Cybulska, Pieczywek, & Zdunek, 2012;Fang et al, 2008;Fraeye et al, 2010;Kastner, Einhorn-Stoll, & Senge, 2012;Ralet, Crépeau, Buchholt, & Thibault, 2003;Ventura, Jammal, & Bianco-Peled, 2013;Videcoq, Garnier, Robert, & Bonnin, 2011;Yang, Zhang, Hong, Gu, & Fang, 2013;Yapo & Koffi, 2013). However, the review of the literature has revealed that there is only very little information on the interaction of pectin with other divalent metal cations, such as magnesium and iron.…”