Cell wall break down of pitanga fruit (Eugenia uniflora L.) is associated with pectic solubilisation and softening

Abstract

Pitanga fruit stands out for its exotic flavour and antioxidant properties. The objective of this work was to evaluate changes in the physical, chemical and biochemical variables of red pitanga variety, in four stages of development (green, yellow, orange and red) and associate them to the cell wall break down. Analysis of pH, titratable acidity, soluble solids, firmness, soluble pectin, pectinamethylesterase (PME), polygalacturonase (PG), cell wall swelling and microstructure were performed. pH and levels of soluble solids and soluble pectin increased, in addition to the cell wall swelling and reduction of firmness, throughout the development of pitanga. From the SEM, it was possible to observe the degradation of the fruit cell wall during ripening, suggesting mainly the degradation of pectic polysaccharides, verified by the solubilisation of these substances. PG and PME enzymes were not active, which suggests that other enzymes may be associated with the cell wall break down.