بررسی تغییرات ضریب آهنگ ثابت خشک‌شدن در مدل‌های شبیه‌سازی با استفاده از پیش‌تیمارهای مختلف

نوع مقاله: مقاله پژوهشی

نویسندگان

1 استادیار، دانشگاه علوم کشاورزی و منابع طبیعی ساری

2 دانشجوی کارشناسی، دانشگاه علوم کشاورزی و منابع طبیعی ساری

چکیده

خشک‌کردن میوه‌ها یکی از راه‌کاره‌های افزایش ماندگاری و استفاده از آن در فصول مختلف سال است. یکی از این میوه‌ها، سیب می‌باشد که برای افزایش مدت ماندگاری آن یا باید در دمای یخچال نگهداری گردد و یا خشک‌شده و به عنوان چیپس سیب مورد استفاده قرار گیرد. در این پژوهش تاثیر پیش‌تیمارهای مختلف شامل آبگیری اسمزی، آلتراسوند، بلانچینگ و مایکروویو در سطوح مختلف و در سه سطح دمایی (45، 55 و C°65) در خشک‌کن جریان هوای گرم، بر زمان خشک‌کردن، شیب منحنی‌های نسبت رطوبت و ضریب آهنگ ثابت خشک‌شدن مورد بررسی قرار گرفت. نتایج حاصل از بکارگیری این پیش‌تیمارها در دماهای مختلف نشان داد که بیشترین زمان خشک‌شدن به میزان 345 دقیقه و در دمای C°45 و در حالت تیمار شاهد و کمترین زمان خشک‌شدن به میزان 75 دقیقه در دمای C°65 و در حالت استفاده از پیش‌تیمار مایکروویو با توان W360 اتفاق افتاد. همچنین بالاترین میزان ضریب آهنگ ثابت خشک‌شدن در پیش‌تیمار مایکروویو در دمای C°65 به میزان min-1 1021/0 و پایین‌ترین میزان این ضریب در دمای C°45 و در تیمار شاهد به میزان min-1 0091/0 بود. تغییرات ضریب آهنگ ثابت خشک‌شدن نشان داد که استفاده از پیش‌تیمارهای مایکروویو و فراصوت به علت تخریب بافت محصول و خروج سریعتر رطوبت سبب افزایش این ضریب نسبت به تیمار شاهد می‌گردند. همچنین استفاده از پیش‌تیمارهای آبگیری اسمزی و بلانچینگ به علت تاثیر کم روی سرعت خروج رطوبت از محصول سبب تغییرات کمی در شیب منحنی‌های خشک‌شدن نسبت به حالت شاهد گردید و به دنبال آن ضریب آهنگ ثابت خشک‌شدن پایین بود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of change Drying Rate Constant coefficient in simulations models with various pretreatments on drying apple

نویسندگان [English]

  • Ali Motevali 1
  • Fatemeh Hedayati 2
1 Assistant professor, Department of Mechanics of Biosystem Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
2 BSc student, Department of Mechanics of Biosystem Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
چکیده [English]

Drying fruits is one of way to increase the shelf time and use it in different seasons of the year. One of these fruits is apple that for increasing shelf time it must either be refrigerated or dried and used as potato chips. In this research was investigated the effect of various pretreatments including osmotic dehydration, ultrasound, blanching and microwave pretreatment different levels and at three temperature levels (45, 55 and 65 °C) in convective dryer on drying time, curve slop of moisture ratio and constant drying rate coefficient. The results of applying this pretreatment at different temperatures showed that the maximum value of drying time was 345 min at 45 °C and in control treatment occurred and minimum value of drying time was 75 min at 65 °C by using microwave pretreatment with power 360 W occurred. Also the highest value of drying rate constant was 0.1020 min-1 in microwave pretreatment at 65 °C and the lowest value this coefficient was 0.0091 min-1 in control treatment at 45 °C.  Change of drying rate constant show that using the microwave and ultrasound pretreatment cause tissue degradation and remove moisture from the product could be faster and this coefficient increased than control treatment. Also using the osmotic and blanching pretreatment due to little effect on moisture migration from the product causes reduction of drying curves slope and then coefficient of constant drying rate than the control treatment and followed by constant drying rate coefficient decreases.     

کلیدواژه‌ها [English]

  • Drying Kinetic
  • Apple slice
  • Convective dryer
  • Drying rate constant
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