خشک‌کردن سیب با استفاده از خشک‌کن خورشیدی با چرخه جاذب در دو حالت تابش مستقیم –همرفتی و غیرمستقیم-همرفتی

هدف: هدف از پژوهش حاضر خشک‌کردن سیب با استفاده از خشک‌کن خورشیدی با چرخه جاذب در دو حالت تابش مستقیم –همرفتی و غیرمستقیم-همرفتی می‌باشد. از دو نوع روش خشک کردن مستقیم و غیرمستقیم با جاذب و بدون جاذب رطوبت و خشک کردن در هوای آزاد استفاده شد. ورقه های سیب آماده‌شده از قبل (طعم دار شده با دارچین) روی یک قطعه توری با ابعاد مشخص قرار گرفت، وزن اولیه نمونه ها اندازه گیری و در داخل خشک‌کن خورشیدی با چرخه جاذب در دو حالت تابش مستقیم –همرفتی و غیرمستقیم-همرفتی، گذاشته شد؛ و طی فرایند خشک شدن سرعت تبخیر، بافت، چروکیدگی، میزان بازجذب آب، میزان حفظ ویتامین c (آسکوربیک اسید) و تغییر رنگ و خصوصیات حسی در سطوح مختلف تیمار (30 درصد ساکارز و بدون ساکارز و صفر، 0.5، 1 و 2 درصد دارچین) بررسی و همچنین چند نمونه به‌عنوان شاهد بدون طعم دار کردن با دارچین به‌تنهایی توسط خشک‌کن خورشیدی خشک شد. تجزیه و تحلیل داده‌ها با روش آماری طرح فاکتوریل کاملاً تصادفی و استفاده از نرم‌افزار آماری spss نسخه 26 صورت گرفت.  ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﭘﮋوﻫﺶ ﻧﺸﺎن داد ﮐﻪ در روش ﻣﺴﺘﻘﯿﻢ و ﻏﯿﺮﻣﺴﺘﻘﯿﻢ، ﺑﺎ و ﺑﺪون ﺟﺎذب رﻃﻮﺑﺖ ﻧﺮخ ﺣﺬف رﻃﻮﺑﺖ در ﻧﻤﻮﻧﻪﻫﺎی ﺑﺪون ﺳﺎﮐﺎرز ﻧﺴﺒﺖ ﺑﻪ ﻧﻤﻮﻧﻪﻫﺎی دارای ﺳﺎﮐﺎرز و دارﭼﯿﻦ ﺑﯿﺸﺘﺮ ﻣ ﯽﺑﺎﺷﺪ و ﻣﻘﺎﯾﺴﻪ ﻧﻤﻮﻧﻪﻫﺎی ﮐﻨﺘﺮل در دو روش ﻣﺬﮐﻮر ﺑﺎ و ﺑﺪون ﺟﺎذب رﻃﻮﺑﺖ ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ﺳﺮﻋﺖ ﺗﺒﺨﯿﺮ ﻧﻤﻮﻧﻪﻫﺎ در ﺟﺎذب رﻃﻮﺑﺖ ﺑﻪ ﺻﻮرت ﻣﻌﻨﯽ دار ﺑﯿﺸﺘﺮ اﺳﺖ. ﻋﻼوه ﺑﺮ اﯾﻦ در ﻧﻤﻮﻧﻪﻫﺎی دارای ﺳﺎﮐﺎرز در روش دارای ﺟﺎذب رﻃﻮﺑﺖ ﺳﺮﻋﺖ ﺗﺒﺨﯿﺮ ﭘﺎﯾﯿﻦ ﺗﺮ ﻣ ﯽﺑﺎﺷﺪ و در روش ﻣﺴﺘﻘﯿﻢ آﻓﺘﺎب در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺧﺸﮏ ﮐﻦ ﺧﻮرﺷﯿﺪی ﺑﻪ ﺻﻮرت ﻣﻌﻨﯽداری ﺳﺮﻋﺖ ﺧﺸﮏ ﮐﺮدن ﭘﺎﯾﯿﻦ آﻣﺪه و ﻧﺘﺎﯾﺞ ﺳﺮﻋﺖ ﺗﺒﺨﯿﺮ در روش ﺧﺸﮏ ﮐﺮدن ﻏﯿﺮﻣﺴﺘﻘﯿﻢ ﻧﯿﺰ ﻧﺸﺎن داد ﮐﻪ ﻫﻤﺎﻧﻨﺪ روش ﻣﺴﺘﻘﯿﻢ، ﻧﺮخ ﺗﺒﺨﯿﺮ ﻧﻤﻮﻧﻪﻫﺎی دارای ﺗﯿﻤﺎر دارﭼﯿﻦ و ﻓﺎﻗﺪ ﺳﺎﮐﺎرز ﺑﯿﺸﺘﺮ از ﻧﺮخ ﺗﺒﺨﯿﺮ در ﻧﻤﻮﻧﻪﻫﺎی دارای ﺳﺎﮐﺎرز و ﮐﻨﺘﺮل ﻣ ﯽﺑﺎﺷﺪ. ﻧﺘﺎﯾﺞ آﻧﺎﻟﯿﺰ ﺑﺎﻓﺖ ﻧﯿﺰ ﺣﺎﮐﯽ از آن ﺑﻮده؛ ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﺳﻔﺘﯽ در روش ﻣﺴﺘﻘﯿﻢ ﺑﺪون ﺟﺎذب ﺑﺮای ﻧﻤﻮﻧﻪﻫﺎی ﺑﺪون ﺳﺎﮐﺎرز ﺑﺎ ﻣ ﯿﺎﻧﮕﯿﻦ ﻫﺎی ﻓﺎﻗﺪ اﺧﺘﻼف ﻣﻌﻨﯽ دار اﺳﺖ. ﻫﻤﭽﻨﯿﻦ دارﭼﯿﻦ ﺳﺒﺐ اﻓﺰاﯾﺶ ﻧﯿﺮوی ﺳﻔﺘﯽ در ﻧﻤﻮﻧﻪﻫﺎی ﺑﺪون ﺟﺎذب رﻃﻮﺑﺖ در روش ﺧﺸﮏ ﮐﺮدن ﻏﯿﺮﻣﺴﺘﻘﯿﻢ ﺷﺪ و ﻧﻤﻮﻧﻪﻫﺎی دارای ﺳﺎﮐﺎرز ﻣﯿﺰان ﭼﺮوﮐﯿﺪﮔﯽ ﮐﻤﺘﺮی داﺷﺘﻪ و ﺑﺎ اﻓﺰاﯾﺶ ﻏﻠﻈﺖ دارﭼﯿﻦ ﻣﯿﺰان ﭼﺮوﮐﯿﺪﮔﯽ اﻓﺰاﯾﺶ و ﺑﯿﺸﺘﺮﯾﻦ اﻓﺰاﯾﺶ در روش ﻣﺴﺘﻘﯿﻢ ﺑﺪون ﺟﺎذب در ﻣﻘﺎدﯾﺮ 2درﺻﺪ دارﭼﯿﻦ و در روش ﻣﺴﺘﻘﯿﻢ ﺑﺎ ﺟﺎذب در ﻏﻠﻈﺖ 1درﺻﺪ دارﭼﯿﻦ ﻣﺸﺎﻫﺪه ﺷﺪ. ﺑﺮرﺳﯽ ﻣﯿﺰان ﺑﺎز ﺟﺬب آب ﻧﯿﺰ در روشﻫﺎی ﺧﺸﮏ ﮐﺮدن ﻣﺴﺘﻘﯿﻢ و ﻏﯿﺮﻣﺴﺘﻘﯿﻢ ﻧﺸﺎن داد ﮐﻪ ﻧﻤﻮﻧﻪ ﻫﺎی دارای ﺳﺎﮐﺎرز ﺷﺮاﯾﻂ ﺑﺎز ﺟﺬب آب ﻣﻄﻠﻮبﺗﺮی داﺷﺘﻪ و ﻣﯿﺰان ﺗﺨﺮﯾﺐ وﯾﺘﺎﻣﯿﻦ cﻧﯿﺰ ﻧﺸﺎن داد ﮐﻪ اﺳﺘﻔﺎده از ﺳﺎﮐﺎرز ﺳﺒﺐ ﺑﻬﺒﻮد ﺣﻔﻆ وﯾﺘﺎﻣﯿﻦ cﻣ ﯽ ﺷﻮد و آﻧﺎﻟﯿﺰ ﺗﻐﯿﯿﺮ رﻧﮓ ﻧﯿﺰ ﺣﺎﮐﯽ از آن ﺑﻮده ﮐﻪ ﻧﻤﻮﻧﻪﻫﺎی دارای ﺳﺎﮐﺎرز در ﻫﺮدو روش ﺷﺮاﯾﻂ ﻣﻨﺎﺳﺐ ﺗﺮی دارﻧﺪ. ﺑﻨﺎﺑﺮاﯾﻦ ﻧﺘﺎﯾﺞ ﻣﺮﺑﻮط ﺑﻪ ارزﯾﺎﺑﯽ ﺧﺼﻮﺻﯿﺎت ﺣﺴﯽ ﻧﺸﺎن داد ﻧﻤﻮﻧﻪ ﻫﺎﯾﯽ ﮐﻪ دارای ﺳﺎﮐﺎرز و ﻏﻠﻈﺖ ﻫﺎی ﻣﺨﺘﻠﻒ دارﭼﯿﻦ ﺑﻮدهاﻧﺪ، ﺑﯿﺸﺘﺮﯾﻦ ﻧﻤﺮه ارزﯾﺎﺑﯽ را درﯾﺎﻓﺖ ﮐﺮده اﻧﺪ. ﻓﻠﺬا ﻣﯽﺗﻮان ﺑﯿﺎن ﮐﺮد ﮐﻪ ﻧﻤﻮﻧﻪ ﻫﺎﯾﯽ ﮐﻪ ﺑﺎ ﻣﺤﻠﻮل اﺳﻤﺰی و ﺳﺎﮐﺎرز ﺧﺸﮏ ﺷﺪه اﻧﺪ ﺑﻪ ﻃﻮرﮐﻠﯽ ﻣﻘﺒﻮﻟﯿﺖ ﺑﯿﺸﺘﺮی ﻫﻢ از ﻟﺤﺎظ ﻓﯿﺰﯾﮑﯽ و ﻫﻢ رﻧﮓ، ﻃﻌﻢ و ﻣﺰه داﺷﺘﻪ اﻧﺪ.

drying apples using a solar dryer with a desiccant cycle in two modes: direct radiation-convection and indirect radiation-convection

the aim of the current research is to dry apples using a solar dryer with a desiccant cycle in two modes: direct radiation-convection and indirect radiation-convection. two types of drying methods, direct and indirect with desiccant and without desiccant, moisture content, and drying in open air were used. pre-prepared apple slices (flavored with cinnamon) were placed on a specific-sized mesh, the initial weight of the samples was measured, and they were placed inside the solar dryer with a desiccant cycle in two modes: direct radiation-convection and indirect radiation-convection. during the drying process, the evaporation rate, texture, wrinkling, water reabsorption, vitamin c retention, color changes, and sensory characteristics at different treatment levels (30% sucrose and without sucrose, 0.5%, 1%, and 2% cinnamon) were examined. additionally, several samples were dried as controls without cinnamon flavoring using the solar dryer. data analysis was conducted using a completely randomized factorial design and the statistical software spss version 26. the results of the study showed that in both direct and indirect methods, with and without desiccant, the moisture removal rate in samples without sucrose was higher compared to samples with sucrose and cinnamon. comparing control samples in both methods with and without desiccant moisture showed that the evaporation rate of samples with desiccant moisture was significantly higher. furthermore, in samples with sucrose, the evaporation rate was lower in the desiccant method, and in direct sunlight drying, the drying rate was significantly lower compared to solar dryer drying. the results of evaporation rates in the indirect drying method also indicated that similar to the direct method, the evaporation rate of samples with cinnamon treatment and without sucrose was higher than that of samples with sucrose and controls. tissue analysis results also indicated that the highest firmness was observed in the direct method without desiccant for samples without sucrose, with no significant difference in means. cinnamon also increased the firmness in samples without desiccant moisture in the indirect drying method, and samples with sucrose had less wrinkling, with an increase in cinnamon concentration leading to more wrinkling, with the highest increase observed in the direct method without desiccant at 2% cinnamon and in the direct method with desiccant at 1% cinnamon concentration. the water reabsorption rate in both direct and indirect drying methods showed that samples with sucrose had better water reabsorption conditions, and the vitamin c degradation rate indicated that the use of sucrose improved vitamin c retention. color change analysis also showed that samples with sucrose had more favorable conditions in both methods. therefore, the results related to sensory evaluation characteristics indicated that samples with sucrose and different cinnamon concentrations received the highest sensory evaluation scores. hence, it can be stated that samples dried with osmotic solution and sucrose generally had better acceptability in terms of physical appearance, color, taste, and flavor.