Role of Pectinesterase and Polygalacturonase in the Formation of Woolliness in Peaches

Abstract

Chilling injury symptoms do not appear in nonripe peaches (Prunus persicu L.) while stored at low temperatures, but a dry-mealy texture (woolliness) appears in chili-injured fruits after ripening. Reduced pectinesterase and polygalacturonase activities were associated with reduced juiciness, reduced levels of water soluble pectins, poor texture and enhanced levels of insoluble pectins in peaches which were ripened after storage at 1°C for more than 3 wk. Pectinesterase and polygalacturonase activities and levels of pectic substances were unaltered in nonripened fruits held at 1°C. Fruits transferred to 20°C for 24 or 48 hr after 1 and 3 or 2 and 4 wk of storage at 1°C did not exhibit woolliness after 5.5 wk of storage. Warming for 12 hr was inadequate to prevent the development of woolliness. The effect of intermittent warming on providing a desirable texture in subsequently ripened fruits was related to enhanced pectmesterase and polygalacturonase activities. Low temperatures appeared to induce this physiological disorder by reducing the capacity to provide adequate levels of pectinesterase and polygalacturonase during subsequent ripening at nonchilling temperatures. Intermittent warming appeared to prevent injury by protecting the capacity to produce adequate levels of pectolytic enzymes during ripening.

Caracterização físico-química e enzimática de uva 'Patricia' cultivada na região de Primavera do Leste - MT

“…A determinação da atividade enzimática da enzima polifenoloxidase (PPO) foi determinada pelo método descrito por Ponting & Joslyng (1948), utilizando-se extrato da amostra sem DOPA como branco. A determinação da enzima pectinametilesterase (PME), foi segundo método descrito por Buescher & Furmanski (1978) para obtenção do extrato e a determinação da atividade enzimática pelo método descrito por Hultin et al (1966). A obtenção do extrato de poligalacturonase (PG) seguiu técnica descrita por Buecher & Furmanski (1978) e a determinação da atividade enzimática pelo método descrito por Markovic et al (1975).…”

Effect of controlled atmosphere on postharvest quality of 'Douradão' peaches

“…Numerous studies have associated woolly fruit with PME activity, although they have presented different conclusions. Woolliness has been related to the reduction of PME activity (BUESCHER;FURMANSKI, 1978) or to an increase (BEN-ARIE; SONEGO, 1980;BRUMMELL et al, 2004;GIRARDI et al, 2005) or to expressionless levels of this enzyme .…”

Volatile profile and physical, chemical, and biochemical changes in fresh cut watermelon during storage

“…The typical aroma of each fruit results from a combination of several volatile substances from various chemical categories that present different physicochemical properties and thresholds (THOMAZINI; FRANCO, 2000), such as esters, lactones, alcohols, acids, aldehydes, ketones, acetals, hydrocarbons and some phenols, and ethers and heterocyclic compounds (CHITARRA;CHITARRA, 2005;BALDWIN, 2002) meaning different biochemical pathways for aroma production, such as lipid peroxidation, aldehyde conversion into alcohols, methylerythritol 4-phosphate and mevalonate pathways, fermentation, etc. (BALDWIN, 2002;MA et al, 2007;PECH;LATCHÉ;van der REST, 2008).…”