The Chemistry of Texture in Fruits and Vegetables

Abstract

This review is concerned with the chemistry of the major primary cell wall components, pectins, hemicelluloses and cellulose, under conditions found during the normal handling of fruits and vegetables. These polymeric components are considered separately, then their combined changes during maturation, storage and processing are covered. The effects of tissue conditions, pH, enzymes and salt concentrations on the rate and degree of change are discussed. A large part of the review deals with the important texture‐affecting reactions of pectic materials including glycosidic hydrolysis, β‐elimination type depolymerization, demethoxylation, and complex formation.

Pectins in Processed Fruits and Vegetables: Part III—Texture Engineering

“…The initial loss of firmness is associated with loss of turgor due to membrane disruption (Greve and others 1994a). Important additional softening occurs partly as a result of solubilization and depolymerization of pectic polymers that are involved in cell-cell adhesion (Van Buren 1979;Greve and others 1994b;Cano 1996;others 1997b, 2003). Chemical pectin depolymerization during heat treatments (see Figure 1) can be explained by ß-elimination and/or acid hydrolysis depending on the degree of methoxylation (DM) and the pH.…”

“…Although no piece of machinery, not even the most sophisticated, has been able to reproduce accurately and comprehensively the events that take place in the mouth upon food ingestion, simple, rapid, and instrumental texture evaluation is often performed as it is considered to be highly objective and appropriate in cases such MS 20080859 Submitted 10/30/2008, Accepted 12/29/2008 as quality control (Lu and Abbott 2004). Nonetheless, whether the perturbing device is a human tooth or an engineered probe, what is being measured or analyzed in textural testing is a response to the structural organization of the material, whereby plant cell walls are the key structural components of most plantbased foods (Van Buren 1979;Waldron and others 2003). The close structure-texture relationship (Jackman and Stanley 1995;Aguilera and Stanley 1999;Wilkinson and others 2000) underscores the need to accompany textural studies with a structural examination both of the native food and samples placed under stress.…”

“…Processes aiming to alter the texture and structure of processed fruits and vegetables often focus on pectin changes (Van Buren 1979;Waldron and others 2003;others 2006a, 2006c). Pectin changes that have been studied most frequently in the context of processing-related texture changes are schematically represented in Figure 1 and are extensively discussed in Part II, the complementary publication by Sila and others.…”

Efeito da acidificação, fermentação e adição de cálcio na qualidade de couve-flor (Brassica oleraceae L.) processada pelo calor

“…Segundo VAN BUREN (1979), a textura é uma importante caraterística dos alimentos e o controle ou melhoria deste atributo constitui um dos principais objetivos da moderna tecnologia de alimentos.…”

The Influence of Pectin from Apple and Gum Arabic from Acacia Tree on the Quality of Pizza

“…10,17,18 During thermal processing of plant tissues, pectin is subject to depolymerization reactions, which result in texture deterioration. 19,20 Depending on pH and degree of methoxylation (DM), β-elimination or acid hydrolysis may occur.…”