Sample size for postharvest quality traits of ‘Palmer’ mangoes

João Claudio Vilvert,Edna Maria Mendes Aroucha,Sérgio Tonetto De Freitas,Eleonora Barbosa Santiago Da Costa,Maria Aparecida Rodrigues Ferreira

doi:10.1590/0100-29452021014

Abstract

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.

Highlights

Material and methodsMango (Mangifera indica L.), known as ‘the king of fruits’, is the second most produced and consumed tropical fruit around the world due to unique features such as its delicate and tropical taste, pleasant aroma and nutritional composition (SINGH et al, 2013; FAO, 2019).The most often used traits to determined mango quality are weight, diameter, skin and pulp colour, texture, dry matter, soluble solids content and acidity (ANDERSON et al, 2017; NORDEY et al, 2016; NTSOANE et al, 2019)
Descriptive statistics represented by average, median, variance, standard deviation, standard error, coefficient of variation, skewness, kurtosis and normality for the physicochemical traits of ‘Palmer’ mangoes harvested in June 2020 and October 2020 are presented in Figures 1, 2, 3 and 4
With an estimation error of 10% and a confidence interval of 95%, 12 fruits are needed in the winter harvest and 14 in the spring harvest

Summary

Introduction

Material and methodsMango (Mangifera indica L.), known as ‘the king of fruits’, is the second most produced and consumed tropical fruit around the world due to unique features such as its delicate and tropical taste, pleasant aroma and nutritional composition (SINGH et al, 2013; FAO, 2019).The most often used traits to determined mango quality are weight, diameter, skin and pulp colour, texture, dry matter, soluble solids content and acidity (ANDERSON et al, 2017; NORDEY et al, 2016; NTSOANE et al, 2019). Harvest maturity is known to play an important role in determining postharvest fruit life and fruit quality. In postharvest studies, determining the most efficient sample size is important to guarantee that each sample will effectively represent the whole fruit batch. Determining the ideal sample size will optimize the time, labour and expenses required for sample analyses (ARELLANO-DURÁN et al, 2018; CARGNELUTTI FILHO et al, 2018). Determination of the most efficient sample size improves the efficiency of the research, allowing different fruit traits to be analysed with the desired precision. The data variability and the desired reliability in the mean estimation are directly proportional to the sample size, while the estimation error allowed is inversely proportional (BUSSAB; MORETTIN, 2017). The higher the variation and/or desired precision, the higher will be the sample size

Objectives

Results

Conclusion