A Fuzzy Approach for Relating a Pomegranate Maturity Index with to Solar Net Radiation

Abstract

Pomegranate fruit maturity status is commonly assessed based on external (skin) colour, juice colour and acidity of juice. Some researchers have studied the correlation between the parameters of the skin colour and acidity, total soluble solids, citric acid and anthocyanins. This study describes the relationship existing between solar radiation and a colorimetric maturity index in the pomegranate varietal group “Mollar de Elche”. We propose a fuzzy methodology. The aim of this kind of study is to obtain on estimation a range of possible values that reflects reality. Using this methodology four phases were obtained, in which there is no relationship between radiation and the colorimetric Maturity Index (MIc) in phases 1 and 4, but there is such a relationship in phases 2 and 3. Fuzzy math demonstrates the positive relationship between radiation and MIc, confirming that fuzzy regression is appropriate for making estimations that reflect reality among variables showing a weak relationship. There is a high degree of uncertainty in the relationship between the colorimetric maturity index and the incident radiation. The individual values of radiation do not correspond to one sole value of MIc, but to a wide range of the same, due to several factors, such as fruit orientation, luminosity, etc. Fuzzy math reveals the positive relationship between net radiation and MIc in phases 2 and 3. All this shows that the fuzzy regression may be appropriate for making estimations reflect reality when the variables show a weak relationship.