بررسی تاثیر پیش تیمار با اتیل اولئات و نوع بسته بندی بر خصوصیات کیفی توت خشک شده در طی مدت نگهداری

Aim of pre-treatment drying of mulberry was to reduce the moisture content to a level that allows safe storage over an extended period. In this research after different combination of ethyl oleate pretreatments, mulberry was dried industrially (cabin dryer). Dried mulberries packed in polyethylene and polystyrene and preserved for 5 months in 20ْ c. Non Enzymatic Browning was tested at 440 nm by spectroscopic method. Organoleptic tests were done by trained panelists. Hardness, Cohesiveness, Springiness and Chewiness of dried mulberries were measured by a texture analyzer. Statistical method was factorial in frame of completely randomized design with two factors and three replicates. Factor A was different pretreatments and factor B was packaging type. The results showed that Least intensity of brown color was in dried white mulberry pretreated by ethyl oleate 2% +ascorbic acid1% and then in ethyl oleate 2% +potassium meta bisulfate 0.5% treatments . The lowest total count was in white mulberry in ethyl oleate 2% +potassium meta bisulfate 0.5%. The results of Panel tests showed highest score for texture, color, odor, taste and overall acceptance in pretreatment of fruits with ethyl oleate 2% +potassium meta bisulfate 0.5%. The results of rheological tests showed that the highest score for chewiness was in white mulberry pretreated with ethyl oleate 2% +potassium meta bisulfate 0.5%. White mulberry pretreated and packaged in poly styrene had the lowest scores for brown color and total count after 5 months storage. Totally it is concluded that dried white mulberry pretreated with combination of ethyl oleate 2% and potassium meta bisulfate 0.5% and packed in poly styrene preserved its qualitative, sensory and rheological characteristics after 150 days in 20ْc .