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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.

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The pineapple is a fruit that has wide acceptance worldwide both in natural form, as industrialized. Your peel is a residue generated by food industries and from this residue can obtain a protein extract which is a good source of bromelain. This study aimed to obtain a protein extract from pineapple peel, evaluate its enzyme activity and its healing properties in skin lesions in rats. Seven animal groups were used: control, treated with 5% of protein extract, 10% of protein extract and pure protein extract; 5% of commercial bromelain, 10% of commercial bromelain and pure commercial bromelain. The animals were subjected to a tissue incision and treated for 21 days. Proteolytic and specific activities of the protein extract were 1.30 U mg -1 and 45 x 10 -3 U μg -1 and, for commercial bromelain, 1.04 U mg -1 and 6 x 10 -3 U μg -1 , respectively. In the histology of the lesion, there was no significant difference between the control and treated groups; however, macroscopically, the prepared topical formulations assisted in the recovery of skin lesions, providing a significant reduction in their width, in the groups treated with pure protein extract, 5 and 10% commercial bromelain, and pure bromelain.

Guava is a highly perishable fruit due to its intense metabolism during ripening, with a shelf life of up to five days at room temperature. The loss of firmness during ripening is caused by the activity of hydrolytic enzymes that promote dissolution of the pectin constituents of the cell wall. Although guava is considered to be rich in pectin, the amounts reported in the literature do not exceed 2.4%, a content indicating it is not responsible for the firmness of guava. The aim of this study was to extract pectin from the guava pulp during 7 days of ripening by two methods (ethanol and EDTA extraction) and suggest modifications in the methods by adding to the extraction residue, cellulase and pectinase to degrade the cell wall structure of the fruit and obtain larger amounts of pectin, which would imply the participation of pectin in the maintenance of fruit firmness. It was possible to infer there were no differences in the pectin levels extracted by the two methods, due to sugar contamination. As from the new stage in the execution by the two methods, the extraction was more efficient: 9.10% of pectin with EDTA and 7.63% with ethanol. The pectin contents found were higher than those mentioned in the literature, better explaining their responsibility in fruit firmness.