مقایسه ویژگی‌های کیفی برگه خرمالو خشک‌شده به دو روش هوای داغ و مادون قرمز

نوع مقاله : مقاله پژوهشی

نویسندگان

• عاطفه فرهمند ¹
• سیده فاطمه موسوی بایگی ²
• مسعود تقی زاده ³
• امین ضیافروغی ⁴

¹ فردوسی مهشد

² دانشگاه فردوسی

³ دانشگاه فردوسی مشهد

⁴ فردوسی مشهد

https://doi.org/10.22067/ifstrj.v0i0.32844

چکیده

در این پژوهش تأثیر خشک کردن به دو روش هوای داغ و مادون قرمز هر کدام در سه سطح دمایی (50، 60 و ◦C 70) بر ویژگی‌های کیفی ازجمله بازجذب آب، شاخص‌های رنگ، چروکیدگی، بافت و خواص حسی برگه خرمالو موردبررسی قرار گرفت. نمونه‌ها با ضخامت ثابت 5 میلی‌متر تا رطوبت نهایی 10% (برحسب وزن مرطوب) خشک شدند. نتایج نشان داد برگه‌های خشک‌شده به‌روش هوای داغ با دمای ◦C 60 و مادون قرمز با دمای ◦C 70، دارای بیشترین میزان بازجذب آب بودند. در رابطه با شاخص L* میان تیمارهای خشک‌شده توسط مادون قرمز در سطح احتمال 95% اختلاف معنی‌داری وجود داشت و نمونه خشک‌شده در دمای ◦C 70، بیشترین میزان این شاخص (33/64) را داشت. حداقل چروکیدگی مربوط به نمونه خشک‌شده به‌کمک مادون قرمز با دمای ◦C 50 بود. نتایج ارزیابی حسی نشان داد که استفاده از مادون قرمز نسبت به هوای داغ در فرآیند خشک کردن، از مقبولیت بیشتری برخوردار است.

کلیدواژه‌ها

• خرمالو
• خشک کردن مادون قرمز
• خشک کردن هوای داغ
• ویژگی‌های کیفی

عنوان مقاله [English]

Quality Characteristics of Persimmon Slices during Infrared and Hot- air Drying

نویسندگان [English]

• Atefeh Farahmand ¹
• Fateme Mousavi Baygi ²
• Masoud Taghizadeh ³
• Amin Ziaforoughi ⁴

¹

² Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad

³

⁴

چکیده [English]

Introduction: One of the most important aspects of food preservation is controlling the moisture of material such as fruits.Dryingis considered as important method to controlbacteriasafely using reduction of moisture. The hot air drying method has been widely adopted in manufacturing of conventional dried food.Nowadays, Infrared radiation (IR) has significant advantages over conventional drying. Among these advantages,higher drying rates giving significant energy savings anduniform temperature distribution giving a better quality of product. Therefore, it can be used as an energy saving drying method. Earlier attempts forapplying infrared waves to drying of agricultural materials have been reported in the literatures, such as banana, onion, garlic, apple, corn, pomegranate seeds and peach. The persimmon (Diospyros kaki) is native to East Asia, most likely China. This fruit has very short shelf-life; it is due to thehigh soluble tannin content of the fruit during storage even at refrigerated conditions. The persimmon is mainly eaten fresh, but can be dried.Duringdrying the tannin cells coagulate, so astringency is removed and the sugars in the fruit exude to the surface where they crystallize, thus producing a sweet, candied product. The objective of this study was to examine the drying behavior of the far infrared and hot- air drying of persimmon slices by comparing the physical quality.
Materials and methods: Persimmon (Diospyros kaki) used in this study was purchased from a local market (KhorasanRazavi, Mashhad). The whole samples were stored at 4°C. The initial moisture content of persimmon was found to be 78.2 kg H2O/kg moisture. The sampleswerecut into 5mm slices using a cutting machine and were dried to 10% final moisture (wet basis).
- Infrared dryer setup: Infrared (IR) dryer used in this research was equipped with IR lamp (1300W). Persimmon slices were placed in a single layer on the drying tray and heated from one side. Thermocouples (Type K) were inserted at the center of persimmon slice.IR drying tests were conducted with final product temperatures controlled at 50°C, 60°C and 70°C.
-Hot air dryer setup: Persimmon slices were arranged in a single layer on the trays and dried in cabinet dryer at material temperatures of 50°C, 60°C and 70°C.Air velocity in the dryer was 1.5 m/s.
-Quality evaluation: Persimmon slice drying characteristics including rehydration ratio, color parameters, shrinkage, texture and sensory properties were investigated
ResultsandDiscussion: It is clear that the moisture content and drying rate decrease continuously with drying time. The drying rate was rapid during the initial period but it became very slow at the last stages of dryingprocess. Persimmonslices dried with hot-air and infrared dryer at temperatures 60 and 70◦c respectively, had a maximum rehydration ratio. In general, infrared drying showed significant effect on L value (p

کلیدواژه‌ها [English]

• Persimon
• Infrared drying
• Hot air drying
• Quality characteristics