Mechanism of firmness loss in guava cv. Pedro Sato during ripening at room temperature

Abstract

Guava (Psidium guajava L.) is fruit with very short shelf life due to associated with the loss of firmness in the pulp and information on the activity of enzymes that degrade pectic substances, as well as the amount of pectin, is very contradictory and not clearly defined. This work showed that the firmness of the fruit decreased sharply on the first four days of ripening. The identified phenolic compounds had their content increased with fruit maturation. The addition of the enzymes cellulase and hemicellulase in the pectin extraction in fruits of Psidium guajava revealed higher contents of this polyssacaride that the ones reported in literature, highlighting pectin as the responsible for the firmness of these fruits at more adequate contents. β-D-glucosidase was identified as one of the responsible enzymes for the maturation of P. guajava fruits. Thus, studies about possible inhibitory effects of this enzyme in P. guajava fruits may reveal an important tool to reduce pectin release and early maturation of these fruits.Keywords: Psidium guajava; pectin; phenolic compounds; β-D-glucosidase; esterase.Practical Application: Guava is a highly perishable fruit and information on the activity of enzymes that degrade pectic substances and the amount of pectin, not are clearly defined. This work showed that the firmness of the Guava decreased with ripenig, that pectin is responsible for the firmness and that the content phenolic compounds increased with fruit maturation. β-D-glucosidase was identified as one of the responsible enzymes for the maturation, thus possible inhibitory effects of this enzyme may reduce pectin release and early maturation of these fruits. Braga et al.

A chromosome‐level genome assembly provides insights into ascorbic acid accumulation and fruit softening in guava (Psidium guajava)

“…This is in accord with prior work showing that the content of soluble pectin (i.e. galacturonic acid) increased with a reduction of guava fruits firmness (Braga et al ., 2017). Together, these results indicate that cell wall degradation may also contribute to fruit softening in guava.…”

“…(2012) and Braga et al . (2017) found that pectin plays an important role in the firmness of guava fruits. Our transcriptomic analysis represents the first investigation of gene expression profiles underlying pathways involved pectin degradation in different tissues and fruit developmental stages in guava.…”

“…The RNA‐Seq analysis in this study supports that enzyme activity and pectin content change during fruit ripening in guava as reported by Braga et al . (2017). Recently, Chen et al .…”

“…Moreover, Braga et al . (2017) found that the amount of pectin in cell walls in guava fruits was too high during fruit maturation for its degradation to explain the softening behaviour. Thus, fruit ripening in guava may follow the starch degradation model.…”

Preharvest Foliar Spray of Calcium Chloride on Growth, Yield, Quality, and Shelf Life Extension of Different Lowland Tomato Varieties in Malaysia

“…The decline in respiration rate by applying higher doses of CaCl 2 may increase the fruit firmness and rigidity. The cell wall, where pectin polymers are mainly considered responsible for fruit firmness, can present glycosidic chains interconnected by phenolic compounds [34]. These phenolic compounds retarded the respiration rate and ethylene production by slowing down the metabolic activity and prolonging the shelf life of tomato fruits [10].…”