Non‐enzymatic Depolymerization of Carrot Pectin: Toward a Better Understanding of Carrot Texture During Thermal Processing

Abstract

Pretreated carrot discs were thermally processed (90 °C to 110 °C) in closed containers and the resulting textural characteristics were analyzed. The pretreatment conditions used include conventional hightemperature blanching (90 °C, 4 min), low-temperature blanching (LTB = 60 °C, 40 min), LTB combined with 0.5% calcium chloride soaking, LTB combined with 2% sodium chloride soaking, high pressure pretreatment (HP = 400 MPa, 60 °C, 15 min), HP combined with 0.5% calcium chloride soaking, and control (non-pretreated sample). Alcohol insoluble residues (AIR) from the pretreated carrot discs were characterized in terms of degree of methoxylation (DM). The AIR samples were further subjected to fractionation into water-soluble pectin (WSP), chelator-soluble pectin (CSP), and sodium carbonate-soluble pectin (NSP). Heat depolymerization patterns and ␤-elimination kinetics were investigated on the different pectin fractions. Thermal texture degradation was strongly influenced by the pretreatment condition used and the processing temperature during subsequent thermal treatment. Pretreatment conditions that showed a significant reduction in DM exhibited decreased WSP content, reduced ␤-elimination, and consequently superior textural characteristics. ␤-elimination was markedly pronounced in the highly methoxylated WSP fractions. CSP and NSP fractions were insensitive to ␤-elimination. A strong correlation (r > 0.95) between thermal texture loss of carrots and ␤-elimination kinetics exists. Overall, the benefits of controlled pectinmethylesterase activity in carrot processing were pointed out.

Effect of thermal and high pressure processes on structural and health-related properties of carrots (Daucus carota)

“…This b-eliminative depolymerisation reaction is accelerated at higher temperatures (Sila, Smout, Elliot, Van Loey, & Hendrickx, 2006). This can explain the more intense hardness loss at 90°C in comparison with 70°C.…”

Modification of Cell Wall Polysaccharides during Drying Process Affects Texture Properties of Apple Chips

“…In addition, relatively low amount of WEP was found in the DIC treated sample, implying that limited amount of soluble pectin existed for this sample. This could be in favor of cell separation during expansion [46]. The FD dried apple chips exhibited the highest content of WEP fraction (102.7 mg/g AIR) among the selected drying methods.…”

Inactivación Térmica de Pectinmetilesterasa en Jugo de Uchuva (Physalis peruviana L.)

“…4. Con un valor P>0,05, para los cuatro atributos del jugo de uchuva, se puede inferir que no existe una diferencia estadísticamente significativa para cada atributo comparado entre el jugo sin tratamiento y los jugos pasteurizados a 70 °C, 80 °C y 90 °C durante 10 s, en resumen el jugo sin tratamiento frente a los jugos pasteurizados no se diferencia estadísticamente, autores como Hirsch et al (2011) encontraron que incluso despues de aplicar una pasteurizacion a 85 °C durante 10 s en jugo de naranja se logró mantener las cualidades organolépticas de un jugo fresco, de igual modo, los tratamientos aplicados al jugo de uchuva no afectan las propiedades organolépticas, sin embargo, hay que tener especial cuidado al aplicar una pasteurización severa, ya que es importante la conservación de las cualidades organolépticas y nutricionales del jugo las cuales se pueden ver afectadas por procesos térmicos prolongados (Sila et al, 2006;Tribess y Tadini, 2006).…”