نوع مقاله : مقاله پژوهشی
نویسندگان
گروه مهندسی شیمی، واحد شیراز، دانشگاه آزاد اسلامی، شیراز، ایران.
چکیده
با توجه به مصرف زیاد رنگ‌های خوراکی در صنایع غذایی، در این پژوهش، اثر فاکتورهایی چون نوع کاتالیست (آمونیوم کلراید وگلایسین)، غلظت کاتالیست (2-5/0 مولار)، میزان pH محیط واکنش (5-4)، زمان انجام واکنش (120-60 دقیقه) بر شدت رنگ کارامل مایع تولید شده از از دو منبع طبیعی خرما و انگور، بر اساس طراحی آزمایش فاکتوریل جزئی بررسی شده است. نتایج نشان داد نوع کاتالیست مصرفی تأثیری بر میزان شدت رنگ نداشت و بیشترین میزان شدت رنگ ( 174/0 برای رنگ تولید شده از انگور و 150/0 برای رنگ تولید شده از خرما) در زمان 120 دقیقه، pH برابر با 4 و غلظت کاتالیست 2 مولار به‌دست آمد. پایدارسازی رنگ‌های مایع تحت فرآیند ریزپوشانی با تولید سه نمونه به فرم جامد (بدون پوشش‌دهنده، همراه با صمغ عربی(شامل 20درصد ماده جامد)، همراه با مالتودکسترین (شامل 20 درصد ماده جامد) انجام شد. نتایج به‌دست آمده از آنالیز گرماسنج حرارتی (TGA) و گرماسنج پویشی تفاضلی (DSC) نشان‌دهنده افزایش مقاومت حرارتی رنگ با فرآیند ریزپوشانی بود؛ به‌گونه‌ای که دمای آغاز تخریب برای نمونه‌های مایع، پودری بدون پوشش‌دهنده، پودری همراه با صمغ عربی و پودری همراه با مالتودکسترین برای رنگ تولید شده از انگوربه‌ترتیب 114، 138، 162، 185 درجه سلسیوس و برای رنگ تولید شده از خرما به‌ترتیب 113، 131، 143، 180 درجه سلسیوس بود. نتایج میکروسکوپ الکترونی روبشی (SEM) نشان داد اندازه پودرهای ریزپوشانی‌شده حدود 11 تا 55 میکرومتر بود.
کلیدواژه‌ها
عنوان مقاله [English]
Feasibility study on caramel color production from grape and date and Microencapsulation of the color by freeze drying
نویسندگان [English]
- Elnaz Ghaem far
- Seyed Mahmoud Reza Hojjati
Department of Chemical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran.
چکیده [English]
Introduction: Adding color to Foods can make them more appealing to consumers, to allow consumers to identify what taste to expect from a product, and to protect sensitive flavors from light. Color has always played a vital role in food selection and acceptance, and colorants are added to foods to alleviate color lost during processing. Caramel color, from the palest yellow to the deepest brown, accounts for more than 80% (by weight) of all colorants added to the foods we eat and drink (Sengar, et al., 2014).Because of sensitivity of liquid colors to oxidation, light and heat and difficulties in their handling and incorporating, dried pigments have been developed. Microencapsulation is a technique to package materials in the form of micro- and nano-particles. There are different methods for encapsulation in the food industry. Freeze drying which has a long dehydration period, has been used as a simple technique in encapsulating water-soluble essential oils and natural aromas or drugs (Khazaei, et al., 2014). In this work, in addition to liquid caramel color production, encapsulation of liquid color with freeze drying technique through wall materials of maltodextrin and Arabic gum were carried out. The stability of microencapsulated color was then evaluated.
Materials and Methods: Rish baba grape and Kabkab date syrup were obtained from local market. Ammonium chloride, citric acid, sodium hydroxide, tween 80, Arabic gum were purchased from Merck (Germany). Glycine and maltodextrin were obtained from Sigma-Aldrich (USA) and Dextrose Company (Iran), respectively. In this study, the effect of factors such as type of catalyst (ammonium chloride-glycine), concentration of catalyst (0.5-2 molar), the pH of reaction (4-5), reaction time (60-120 minutes) on liquid color intensity of caramel produced from two natural sources of date and grape were investigated based on fractional factorial experimental design. For production of liquid caramel color, grape/date syrup was heated while being stirred to 65ᵒ C. Catalysts were then added to syrup and heated to 110ᵒC. water was added to reaction product and centrifuged. The solvent was removed by rotary evaporator (IKA HB 10, Germany).The resulting caramel color was stored under refrigeration at 4ᵒ C. In order to produce powder of caramel color, wall materials including Arabic gum and maltodextrin were dissolved in distilled water at ambient temperature to obtain 20% total solids concentration and stirred for 30 minutes at 60ᵒC. The mixture of liquid caramel color, tween80, and wall material solution was mixed in a ratio (w/w) of 1:4 (liquid caramel color: wall material) and stirred for 15 minutes. The mixture was then dried in a freeze dryer (ALPHA 1-2 LD PLUS, Germany) for 24 hours. The blank sample was prepared without wall materials and freeze-dried in similar conditions with other samples in 24 hours. Dried materials were collected and stored in brown glass bottles with screwed caps at 4⁰C until analysis. The powders were characterized using TGA/DSC thermogravimetric analysis (METTLER TOLEDO, USA), scanning electron microscopy (SEM) (TESCAN vegar, Czech Republic) and X-ray diffraction (XRD) (Billerica, MA, USA) to confirm the structural and morphological aspects of powders.
Results & Discussion: The results showed that the type of catalyst had no effect on the intensity of the colors and maximum color intensity (0.174 for color produced from grape and 0.15 for color produced from date) was obtained under these conditions: 120 minutes for reaction time, pH value = 4 and catalyst concentration of 2 molar. Results of thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) indicated the increase of thermal resistance by microencapsulation process so that initial decomposition temperature for liquid form, without wall material, with Arabic gum and with maltodextrin for grape source were 114,138,162,185°C respectively and for date source were 113,131, 143, 180°C respectively. Results of Scanning electron microscope demonstrated that size of the powders were 11-55 μm. In conclusion, microencapsulation by freeze drying could be recommended as a suitable method for stabilizing caramel color.
کلیدواژه‌ها [English]
- Food color
- Caramel
- Grape
- Date
- Factorial
- Encapsulation
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