Evaluation of fruit quality characteristics of Libyan and imported navel oranges

Abstract

The aim of this study was to investigate the quality of local Libyan navel orange fruits (LNOF) and imported Egyptian (ENOF) and Tunisian navel orange fruit (TNOF) marketed in Libyan markets. This study also investigated the potential advantages that may grant Libyan navel orange any marketing or competition in local and international markets.

This study was carried out in the postharvest laboratory of the western region branch of Libyan agricultural research center in Tripoli. Navel orange fruits of the three geographical sources were sampled weekly from mid-January 2014 to the end of March 2014 according to its availability. The experiment was a complete randomized design with four replicates, each included four sound fruit. The studied characters were fruit weight, longitudinal and equatorial diameter, extractable juice, total soluble solids (TSS), total acidity (TA) and fruit granulation. Results indicated that the ENOF was significantly higher for fruit weight, longitudinal and equatorial diameters, and their ratio compared with LNOF and TNOF. Variables for LNOF were not significantly different from those of TNOF with the exception of the longitudinal-equatorial diameter ratio.

The TNOF had significantly the highest extractable juice percentage followed by the LNOF and then the ENOF. The TNOF was significantly higher for TA compared with the LNOF and the ENOF. The LNOF showed significantly higher TSS compared with those from the other two sources. The TNOF had significantly higher amount of TSS than the ENOF. The three geographical sources of navel orange showed significant differences for the TSS/TA  ratio, where the LNOF was the highest in TSS/TA followed by the ENOF and the TNOF. ENOF exhibited granulation in the samples studied, while LNOF and TNOF were free from any granulation. The results of this study showed presence of preferential differences between the LNOF and both TNOF and ENOF, where the LNOF was characterized by high value of TSS and TSS/TA ratio that gave LNOF an advantage in local and international markets.

Key words: navel orange, total soluble solid, extractable juice, acids.