Microscopic evidence for Ca2+ mediated pectin–pectin interactions in carrot-based suspensions

Abstract

This study explored the use of fluorescently labeled pectin to obtain evidence for Ca(2+) mediated pectin-pectin interactions in situ. Specifically, carrots were either blanched at low temperature (LTB) or blanched at high temperature (HTB) to activate or inactivate endogenous pectin methylesterase, respectively. Consequently, pectin in tissue particles of LTB and HTB carrots exhibited low degree of methylesterification (DM) and high DM, respectively. Pectin present in the LTB carrot serum exhibited a lower DM, was more branched, and showed a higher molar mass compared to HTB carrot serum pectin. Ca(2+) mediated pectin-pectin interactions were influenced by serum pectin molecular structure, increased with increasing pH and Ca(2+) concentration, and decreasing DM. Presence of more linear pectin in the serum created a competition, leading to less intense interactions between labeled pectin and pectin at tissue particle surfaces. Generally, the most intense Ca(2+) mediated pectin-pectin interactions were observed for pectin of LTB carrot particles.

Comparison of selected clean and green extraction technologies for biomolecules from apple pomace

“…Pectin DM measurement was completed using FTIR spectroscopy according to the method described elsewhere with minor modifications. In a typical experiment, a lyophilized pectin sample was firmly pressed into a compact slab and placed on the sample holder of the FTIR (NICOLET iS50 FTIR, ThermoFisher, UK) and scanned 100 times for transmittance between 4000 and 650 cm −1 at a resolution of 0.5 cm −1 .…”

“…The DM was then predicted by calculating the absorption intensity at 1740 cm −1 and 1630–1600 cm −1 according to the method illustrated by Kyomugasho et al. .…”

Deliberate processing of carrot purées entails tailored serum pectin structures

“…In this context, Christiaens et al (2012) observed a shift in pectin solubility (decrease in water soluble pectin and an increase in both chelator soluble and sodium carbonate soluble pectin) in carrot purée prepared from low temperature blanched (60 °C for 40 min) carrot pieces. Recently, Kyomugasho et al (2015a) also reported a low galacturonic acid content in the serum of carrot purée prepared from low temperature blanched carrot pieces. The decreased pectin solubility, due to the increased amount of free carboxyl groups that can cross-link with Ca 2+ or other ions, explains the lower uronic acid (Thakur et al, 1997).…”

“…In contrast, an increase in carrot purée consistency was observed with low temperature blanching of carrot pieces followed by either blending or high pressure homogenization because of increased resistance to particle disintegration as a result of stronger intercellular adhesion by Ca 2+ cross-linking of de-methylesterified pectin. Furthermore, Kyomugasho et al (2015a) also reported that pectins with different characteristics leached into the serum of carrot dispersions depending on the applied treatment (i.e. high or low temperature blanching) during subsequent mechanical disintegration.…”

Tratamento térmico e químico para controle da atividade da poligalacturonase no albedo do maracujá

“…Quando altos níveis deste íon se acumulam no apoplasto, ocorrem ligações cruzadas de cálcio com a pectina. Assim, há forte inibição da liberação das pectinas da parede celular e também supressão da atividade da PG (Rose, 2003;Kyomugasho et al, 2015).…”