ABSTRACT Although acerola (Malpighia emarginata D.C.) has been suggested to be a climacteric fruit, little is known about its sensitivity to exogenous ethylene. The objective of the study was to evaluate the quality changes of acerola fruit at two harvest maturity stages in response to external ethylene application. ‘Flor Branca’ and ‘Junko’ acerolas were harvested at the maturity stages 1 (green fruit with density>1 g cm-3) and 2(green fruit with density <1 g cm-3) and were treated with 0 or 1,000 µL L-1 of ethylene for 24 hours at 12 ºC.The fruit were stored at 12 ºC with relative humidity of 90-95% for 14 days. Both cultivars harvested at the maturity stage 2 showed skin color change from green to red during storage, which was not observed in fruit harvested at the maturity stage 1.External ethylene had no effect on 'Flor Branca' and 'Junko' acerolas respiration rate, flesh firmness, skin color, weight loss, soluble solids (SS), titratable acidity (AT), SS/AT ratio, and ascorbic acid contents. The classification of green acerolas by density was an effective approach to determine fruit harvest maturity for fresh consumption.

Resumo O objetivo deste estudo foi determinar o tamanho da amostra mais eficiente necessário para estimar a média dos caracteres de qualidade pós-colheita de mangas ‘Palmer’ colhidas em duas estações. Cinquenta mangas foram coletadas no estágio de maturação 2, no inverno (junho de 2020) e na primavera (outubro de 2020), e avaliadas quanto à massa, comprimento, diâmetros ventral e transversal, L*, C* e hº de casca e de polpa, matéria seca, firmeza, sólidos solúveis (SS), acidez titulável (AT) e relação SS/AT. De acordo com os resultados, o coeficiente de variação (CV) dos caracteres de qualidade dos frutos variou de 2,1 a 18,1%. O maior CV, em ambas as safras, foi observado para a relação SS/AT, enquanto o menor foi reportado para hº da polpa. Para estimar a média dos caracteres físico-químicos de mangas ‘Palmer’, são necessários 12 frutos na colheita de inverno e 14 da primavera, considerando um erro de estimativa de 10% e um intervalo de confiança de 95%. A AT e a relação SS/AT exigiram o maior tamanho de amostra, enquanto L* e hº exigiram o menor tamanho de amostra. Conclui-se que a variabilidade foi diferente entre os caracteres físico-químicas e as estações, implicando que diferentes tamanhos de amostra são necessários para estimar a média de diferentes caracteres de qualidade em diferentes estações.

Abstract The objective of this study was to determine the most efficient sample size required to estimate the mean of postharvest quality traits of ‘Palmer’ mangoes harvested in two growing seasons. A total of 50 mangoes were harvested at maturity stage 2, in winter (June 2020) and spring (October 2020), and evaluated for weight, length, ventral and transverse diameter, skin and pulp L*, C* and hº, dry matter, firmness, soluble solids (SS), titratable acidity (TA) and the SS/TA ratio. According to the results, the coefficient of variation (CV) of fruit quality traits ranged from 2.1% to 18.1%. The highest CV in both harvests was observed for the SS/TA ratio, while the lowest was reported for pulp hº. In order to estimate the mean of physicochemical traits of ‘Palmer’ mangoes, 12 fruits are needed in the winter and 14 in the spring, considering an estimation error of 10% and a confidence interval of 95%. TA and the SS/TA ratio required the highest sample size, while L* and hº required the lowest sample size. In conclusion, the variability was different among physicochemical traits and seasons, implying that different sample sizes are required to estimate the mean of different quality traits in different growing seasons.