Evaluation of Rutability, Quality and Microbial Load in Hayani Date Palm Fruits During Cold Storage as Affected by Applying some Safe Post harvest Treatments
This work was carried out during the two successive 2014 & 2015 seasons in the post-harvest lab., Agricultural Development System Project, Faculty of Agric. Cairo University, Giza, Egypt. The efficacy of using some safe substances i.e., chitosan ( 0.75 and 1.5%) and sodium carbonate at 0.75 and 1.5 %, along with, control on storability, microbial load of Hayani date palm fruits and its quality under cold storage conditions (2 °C and 90 – 95 % relative humidity) was studied. It was observed that two conflicted trends were resulted with prolonging of cold storage period during both seasons. The percentage of weight loss, decay, rutab, soluble solids content and total sugars of fruits were increased; while fruit firmness, acidity and soluable tannins values were relatively reduced. Moreover, the different Hayani fruits measurements according to various tested treatments varied not only from one treatment to other but also, each characteristic reflected its own trend from the other side. Therefore, it could be concluded that all soaking treatments significantly reduced the fruit microbial load and decay percentage compared to control (water dipping). On the other hand, 1.5 % chitosan treatment was the superior. Chitosan treatments reduced the level of microorganisms load compared with control. At the same trend Sodium carbonate treatments reduced also, both bacterial and fungal count during the storage period of Hayani date. Four deferent fungi were isolated and identified from Hayani date as Aspergillus niger, A. flavus, Rhizopus nigricans and Penicillium sp. On the contrary of that, the total acidity was slightly affected by different treatments. The difference was more significant particularly with the two tested concentrations of chitosan during both seasons of study. Furthermore, the fruit firmness, total sugars and tannins content significantly affected by various treatments.