Quality of 'Pedro Sato' guavas as function of postharvest alternative treatments/Qualidade de goiabas 'Pedro Sato' em funcao de tratamentos alternativos em pos-colheita

This study aimed to evaluate the effect of alternative products and thermotherapy, singly and in combination, on the physicochemical quality and controlling decay of 'Pedro Sato' guavas. Initially the treatments with calcium chloride, potassium phosphite, 1-methylcyclopropene (1-MCP), cassava starch, ethanol followed by chlorine (ethanol+chlorine) and thermotherapy were evaluated for eight days of fruits storage at 22°C. In a second step, four treatments were selected (cassava starch, 1-MCP, thermotherapy and ethanol+chlorine) and evaluated the association of two, applied sequentially, during eight days of fruits storage at 25°C. The 1-MCP treatment and cassava starch were the most effective in keeping the physicochemical quality of 'Pedro Sato' guavas, slowing the weight loss, change of skin color, and contributing to firmness retention. Greater reduction in fruit rot was found in thermotherapy, cassava starch and 1-MCP treatments. The associations of 1-MCP/cassava starch and thermotherapy/cassava starch were the most effective treatments to maintain the quality of 'Pedro Sato' guavas, slowing the weight loss, change of skin color, and loss of firmness. Association treatments reduced incidence of decay, especially the ethanol+chlorine/ thermotherapy and thermotherapy/cassava starch that were more efficient until the fourth day of storage. The rots incidence correlated with parameters of skin color and firmness for most association treatments. In general, it is recommended the thermotherapy/cassava starch for guavas stored at 22-25°C as a way of maintaining the physicochemical quality and delaying at least two days the symptoms of decay.