نوع مقاله : مقاله پژوهشی فارسی
نویسنده
گروه مواد و طراحی صنایع غذایی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان.
چکیده
کاربرد افزودنیها بهویژه ترکیبات هیدروکلوئیدی در کاهش جذب روغن در دونات یک روش کاربردی است؛ زیرا نیاز به ایجاد تغییرات در طراحی صنعتی تجهیزات نمیباشد. بنابراین، در این پژوهش تأثیر صمغ زانتان و کربوکسیمتیل سلولز در خصوصیات کیفی دونات با هدف کاهش جذب روغن مطالعه شد. برای این منظور، در فرمولاسیون خمیر دونات از صمغهای زانتان، کربوکسیمتیل سلولز و نسبت ترکیبی این دو صمغ (50:50) بهمیزان 5/0، 1 و 5/1 درصد براساس وزن ماده خشکِ خمیر استفاده شد. خمیر دونات آماده شد و قالبگیری انجام گرفت. تخمیر در شرایط مشابه صنعتی (دمای 40 درجه سانتیگراد و رطوبت 40 درصد) بهمدت 30 دقیقه صورت پذیرفت. سپس بهترتیب فرآیند سرخکردن در دمای 180 درجه سانتیگراد، قرار دادن آیسینگ و بستهبندی انجام شد. محتوی رطوبت خمیر و دونات، جذب روغن دونات، دانسیته، رنگ و نسبت تخلخل نمونهها اندازهگیری شد. همچنین، خصوصیات کیفی ماندگاری شامل ارزیابی نرمی بافت، عدم جذب آیسینگ و عدم رشد کپک طی 14 روز بررسی گردید. تجزیه و تحلیلهای آماری در قالب طرح کاملاً تصادفی انجام شد (05/0>p). نتایج نشان داد که رطوبت نمونهها با افزایش درصد ترکیبات هیدروکلوئیدی همواره افزایش یافت. جذب روغن با افزایش درصد صمغ کاهش یافت و کمترین محتوی روغن در نمونههای حاوی میزان 5/1 درصد صمغ زانتان مشاهده شد (محتوی روغن برابر با 174/0 گرم روغن بر گرم ماده خشک). برخلاف زانتان، با افزایش درصد صمغ کربوکسیمتیل سلولز دانسیته کاهش یافت و بیشترین دانسیته معادل با 610/0 گرم بر سانتیمتر مکعب بود که در میزان 5/1 درصد صمغ زانتان مشاهده شد. بنابراین بیشترین تخلخل و نرمی بافت نیز در نمونههای حاوی کربوکسیمتیل سلولز با توجه به افزایش حجم یافت شد. عدم جذب آیسینگ در نمونههای حاوی زانتان کمتر بود. رشد کپک در هیچ تیماری مشاهده نشد. درمجموع، بهترین نسبت افزودنی صمغ زانتان از نظر کاهش جذب روغن، کاربرد آن بهمیزان 5/0 درصد بود. زانتان بهدلیل خصوصیات تشکیل ژل حرارتی و غلیظ شوندگی بیشترین کاهش جذب روغن را نشان داد.
کلیدواژهها
موضوعات
عنوان مقاله [English]
Application of hydrocolloid compounds (xanthan and carboxymethylcellulose) in doughnut formulation for reducing oil uptake
نویسنده [English]
- Hassan Sabbaghi
Department of Food Materials and Design Engineering, Gorgan University of Agricultural Sciences and Natural Resources.
چکیده [English]
Introduction: Doughnuts are fried foods that absorb significant amounts of oil, and commercial doughnuts made from wheat flour typically contain 24 to 26 percent oil. The use of additives, especially hydrocolloid compounds, in reducing the oil uptake in doughnuts is a practical method because there is no need to make changes in the industrial design of the equipment. Usually, the level of these compounds used to achieve the desired properties in food systems is less than 2% dry basis. When these compounds are added to the dough, they form a gel as soon as possible, which has a high water holding capacity in contact with hot oil, and this will be effective in maintaining and controlling the moisture content of the product and preventing oil penetration. Controlling moisture outflow from the product reduces the rate of moisture migration and compounds from the food into the frying oil, and subsequent peroxidation reactions in the oil consumed are reduced, thus increasing the useful life of the oil. Therefore, in this study, the effect of xanthan gum and carboxymethylcellulose on doughnut quality characteristics was studied.
Materials and Methods: For this purpose, in the formulation of doughnut dough, xanthan gums, carboxymethylcellulose and a combination of these two gums (50:50) were used at the rate of 0.5, 1 and 1.5 percent based on the weight of the dry matter of the dough. The doughnut dough was prepared and molded. The fermentation was carried out for 30 minutes under similar industrial conditions (40°C and 40% humidity). Then the frying process at 180°C, icing and packaging were performed, respectively. The moisture content of the dough and doughnuts, the oil uptake of doughnut, density, color and the porosity ratio of the samples were measured. Also, the qualitative characteristics of shelf life, including soft tissue assessment, non-absorption of icing and non-growth of mold were investigated within 14 days. Statistical analysis was performed in a completely randomized design (p<0.05).
Results and Discussion: The results showed that, the moisture content of the samples always increased with elevating the percentage of hydrocolloid compounds. Oil absorption decreased with increasing gum percentage and the lowest oil content was observed in the samples containing xanthan gum. Unlike xanthan, the density decreased and the volume increased with elevating the percentage of carboxymethylcellulose gum. Therefore, the highest porosity and softness of the tissue were found in samples containing carboxymethylcellulose. The brightness parameter (L*) was higher in samples containing xanthan, which could be due to the higher moisture content. The red parameter (a*) was also higher in the samples containing xanthan, which due to the higher compression of the product, a relatively more red pigment was observed with increasing xanthan level. The yellowness parameter (b*) in xanthan-containing samples was lower due to reduced oil absorption. The intensity of the color changes (dE) decreased as the percentage of gums increased. Non-absorption of icing was less in hard sample containing xanthan, which could be due to xanthan's competition with gluten in suction of surface water. Mold growth was not observed for any treatment. Overall, the best additive ratio of xanthan gum was 0.5% in terms of reduced oil absorption. Also, the use of carboxymethylcellulose at the level of 0.5% alone could improve the softening of the product texture and made the doughnut with larger volume. Simultaneous use of xanthan gum and carboxymethylcellulose showed behavior under effect of xanthan gum.
In general, xanthan gum was more effective than carboxymethylcellulose gum in reducing oil uptake and moisture retention at test levels. Xanthan has shown the greatest reduction in oil absorption due to its thermal gelling and thickening properties, as it has a high capacity for water retention when product is in contact with hot oil. Since the xanthan gum is inexpensive, its effects on product volume can be further investigated in research work, along with bulking agents or other hydrocolloid compounds.
کلیدواژهها [English]
- Oil uptake
- Doughnut
- Frying
- Xanthan
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