Pectin fraction interconversions: Insight into understanding texture evolution of thermally processed carrots.
In situ changes in pectin fractions for thermally processed carrots were related to textural changes. The texture of pretreated and subsequently thermally processed carrot disks was determined. Alcohol insoluble residue (AIR) was extracted from the pretreated and thermally processed tissues. The AIR was characterized in terms of the degree of methylation (DM) and changes in pectin fractions. Distinct differences in texture and DM were observed during thermal processing. Pretreatment conditions that induced a significant decrease in DM showed better textures. Demethoxylation caused interconversion of pectin fractions, water soluble pectin (WSP) changing into water insoluble pectin [chelator (CSP) and alkali (NSP) soluble pectin]. This process was reversed during cooking accompanied by remarkable alterations in molecular weight (MW) distribution patterns. The WSP depicted polydisperse MW distribution patterns, strongly dependent on the pretreatment condition. Confirmatory results of interconversions of pectin fractions (WSP, NSP) were demonstrated by the MW distribution patterns and neutral sugar profiles. All thermal related transformations of pectin structural parameters were decelerated by lowering the DM.
Sila
Daniel N
DN
Center for Food and Microbial Technology, Laboratory of Food Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, B 3001 Heverlee, Belgium.
Doungla
Eugenie
E
Smout
Chantal
C
Van Loey
Ann
A
Hendrickx
Marc
M
D003296:Cooking; D018552:Daucus carota / Q000737:chemistry; D006244:Hardness; D006863:Hydrogen-Ion Concentration; D008745:Methylation; D008970:Molecular Weight; D010368:Pectins / Q000032:analysis* / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry
D011134:Polysaccharides; D014867:Water; D010368:Pectins