Unravelling process-induced pectin changes in the tomato cell wall: An integrated approach
Unravelling process-induced pectin changes in the tomato cell wall: An integrated approach
复制标题
DOI：
10.1016/j.foodchem.2011.11.148
复制
发表时间：
2012-06-01
期刊：
影响因子：
8.8
通讯作者：
Hendrickx, Marc E.
中科院分区：
文献类型：
--
作者：
Christiaens, Stefanie;Van Buggenhout, Sandy;Hendrickx, Marc E.
通过加工调整番茄果实中果胶修饰酶果胶甲酯酶（PME）和多聚半乳糖醛酸酶（PG）的活性。番茄要么未经预处理，要么进行高温漂烫（使PME和PG均失活），要么进行高压预处理（使PG选择性失活）。随后，采用两种机械破碎方式，即搅拌或高压均质，以制备具有不同组织破碎程度的番茄组织颗粒悬浮液。利用抗果胶抗体通过原位果胶可视化研究加工诱导的果胶变化及其在细胞 - 细胞黏附中的作用。对分级细胞壁和分离的聚合物进行（有限的）物理化学分析，为显微镜观察结果提供了支持。研究表明，在完整的番茄果实中，果胶的去酯化作用是通过细胞壁基质中PME活性的物理限制进行内源调节的。另一方面，在破碎的番茄组织中，PME的活性使果胶在整个细胞壁中发生强烈的去酯化作用。PG被选择性失活（即在高压预处理的番茄中），同时PME使果胶去酯化，这导致大量的钙离子交联果胶和强烈的细胞间黏附。另一方面，在未经预处理的番茄悬浮液中，PME和PG的联合活性可能导致果胶解聚，从而降低细胞间黏附。然而，由于这些样品中大量的钙离子交联果胶，细胞 - 细胞黏附仍然比高温漂烫的番茄更强，在高温漂烫的番茄中，悬浮液制备过程中PME活性的缺失意味着钙离子交联的果胶聚合物很少，组织破碎时细胞大量分离。（C）2011爱思唯尔有限公司。保留所有权利。
The activity of the pectin-modifying enzymes pectin-methylesterase (PME) and polygalacturonase (PG) in tomato fruit was tailored by processing. Tomatoes were either not pretreated, high-temperature blanched (inactivation of both PME and PG), or high-pressure pretreated (selective inactivation of PG). Subsequently, two types of mechanical disruption, blending or high-pressure homogenisation, were applied to create tomato tissue particle suspensions with varying degrees of tissue disintegration. Process-induced pectin changes and their role in cell-cell adhesion were investigated through in situ pectin visualisation using anti-pectin antibodies. Microscopic results were supported with a (limited) physicochemical analysis of fractionated walls and isolated polymers. It was revealed that in intact tomato fruit pectin de-esterification is endogenously regulated by physical restriction of PME activity in the cell wall matrix. In disintegrated tomato tissue on the other hand, intensive de-esterification of pectin by the activity of PME occurred throughout the entire cell wall. PG was selectively inactivated (i.e. in high-pressure pretreated tomatoes), with de-esterification of pectin by PME, which resulted in a high level of Ca2+-cross-linked pectin and a strong intercellular adhesion. In non-pretreated tomato suspensions on the other hand, combined PME and PG activity presumably led to pectin depolymerisation and, hence, reduced intercellular adhesion. However, because of the high amount of Ca2+-cross-linked pectin in these samples, cell-cell adhesion was still stronger than in the high-temperature blanched tomatoes, in which the absence of PME activity during suspension preparation implied few Ca2+-cross-linked pectic polymers and extensive cell separation upon tissue disruption. (C) 2011 Elsevier Ltd. All rights reserved.