This work aimed to evaluate the effect of mechanical injury, impact, compression or cut, on respiratory activity and chemical composition of fruits of two guava cultivars, harvested at mature-green stage and stored to 23.4±1 °C and 62±6 % RH (laboratory conditions). To produce impact injury, fruits were dropped, twice, from a height of 1.20 m against a hard surface. The compression injury was produced in fruits submitted to the action of a weight (3 kg) for 15 minutes. Cut injury was obtained by cutting fruits, twice, in the longitudinal direction, with exactly 30 mm length and two mm depth. The fruits were packed in trays and stored under laboratory conditions. The respiratory activity was evaluated daily and chemical composition every two days (total soluble solids, reducing sugars, total titratable acidity and ascorbic acid). There was an increase in respiratory activity of the fruits during the storage, with injured producing more CO2 (184.12 mg of CO2.kg-1.h-1) than the control (164.23 mg of CO2.kg-1.h-1), for both cultivars. 'Paluma' fruits presented respiratory activity (178.39 mg of CO2.kg-1.h-1) higher than 'Pedro Sato' (169.35 mg of CO2.kg-1.h-1), and climacteric peak was not detected. The total soluble solids (9.39 °Brix), reducing sugars (2.24 g of glucose.100 g-1), total titratable acidity (706.25 mg of citric acid.100 g-1) and ascorbic acid (65.33 mg of ascorbic acid.100 g-1) contents in injured fruits were smaller than in control, along the storage period.
Psidium guajava; postharvest; impact; compression; cut; respiration; chemical composition
