نوع مقاله : مقاله پژوهشی
نویسندگان
گروه علوم و صنایع غذایی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
چکیده
هدف از این پژوهش بررسی خواص رئولوژیکی خمیر و بیاتی نان حاصل از آرد گندم در اندازه ذرات مختلف و تحت تأثیر تیمارهای حرارتی متفاوت بود. برای این منظور آرد گندم در اندازه ذرات مختلف (180، 150 و 125 میکرون) تهیه و تحت تیمار حرارتی خشک به‌مدت 10 دقیقه در دمای 100 درجه سانتی‌گراد و تیمار حرارتی مرطوب (رطوبت، 16 درصد) به‌مدت 5 دقیقه در دمای 96 درجه سانتی‌گراد قرار گرفت و با نمونه‌های شاهد (بدون حرارت‌دهی) مقایسه شدند. نتایج نشان داد تأثیر اندازه ذرات و تیمار حرارتی خشک بر رئولوژی خمیر و فعالیت آبی مغز و پوسته نان معنی‌دار بود، در حالی‌که بهترین تعادل ویسکوالاستیک (P/L) خمیر را و کمترین میزان فعاالیت آبی مغز و بیشترین میزان فعالیت آبی پوسته نان را نمونه تیمار حرارتی خشک با اندازه ذرات 180 میکرون در مقایسه با سایر نمونه‌ها داشتند. تیمار حرارتی مرطوب با اندازه ذرات 180 میکرون در مقایسه با سایر نمونه‌ها از رطوبت مغز نان بیشتری برخوردار بود. طبق نتایج بدست آمده تیمار حرارت خشک تأثیری بر بافت نان‌ها نداشت، در حالی‌که بکارگیری آرد حاصل از تیمار حرارتی مرطوب با اندازه ذرات 180 میکرون با کاهش میزان سفتی و قابلیت جویدن منجر به بهبود ویژگی بافت نان گردید. نتایج حاصل از آنالیز حرارتی نشان داد نمونه تیمار حرارتی مرطوب با اندازه ذرات 180 میکرون کمترین میزان آنتالپی را داشته و بهترین نمونه بود. به‌طور کلی استفاده از آرد با اندازه ذرات 180 میکرون و تیمار حرارتی مرطوب با بهبود خواص رئولوژیکی و بیاتی نان بهترین نمونه بودند.
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
The Effect of Wet and Dry Heating Process and Wheat Flour Particle Sizes on Dough Rheology and Staling of Bread
نویسندگان [English]
- Mohammad Fazli Rad
- Jafar Milani
- Sepide Haghighat
Department of Food Science and Technology, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
چکیده [English]
Introduction
Wheat plays a major role in global nutrition but it cannot be used without processing. The nutritional importance of wheat flour is due to the presence of gluten proteins that create viscoelastic properties. Gluten as a protein inhibits the staleness of bread. Physical modification of flour is a safe method without using any kind of chemicals. Physical modification of flour includes heat treatment and particle size classification. Particle size distribution is the most widely used technique for classifying solid particles, which is effective in improving rheological properties by affecting the physicochemical properties of flour during hydration, such as water absorption, solvent retention, sedimentation, and adhesion properties. Heat treatments, depending on the intensity of temperature and process time, by modifying starch granules, denaturing proteins, and deactivating enzymes, reducing microbial load, and even modifying flavor and aroma are suggested as a suitable way to improve the quality of bread, especially for weak flour. Considering that the interaction of particle size with wet and dry heating of wheat flour on the rheological properties of dough and staleness of bread has not been studied so far. In this research, by dividing wheat flour with different particle sizes and using wet and dry heat treatments for modification the functional characteristics of wheat flour and the improvement of the rheological characteristics of dough and staleness of bread were investigated.
Materials and Methods
The content of moisture, pH, ash, protein, and Zeleny number of wheat flour was measured using the AACC standard method (2000), and wet and dry gluten with the standard number (9639-1, 3) was measured. To classify the size of the particles, wheat flour was divided by a shaker sieve with different sizes of 180, 150, and 125 microns, then under the influence of dry heat treatment for 10 minutes at 100 degrees Celsius and moist heat treatment with 16% humidity for 5 minutes at a temperature of 96 degrees Celsius was placed. Materials for bread formulation for 100 g of wheat flour included 58 ml of water, 2.5 g of sugar, 1 g of salt, 1 g of vegetable oil, and 2 g of yeast. The rheological parameters of the dough were measured by an alveography device. To check the staleness of bread during the storage period, moisture tests of core and shell, blue activity of core to shell, analysis of bread texture, and DSC were performed. Finally, the factorial test was used to investigate the effects of particle size and heat treatment on wheat flour, and Duncan's multiple range test was used to compare the means at the 5% probability level.
Results and Discussion
The results showed that the effect of particle size and dry heat treatment on dough rheology and water activity of bread core and crust was significant, while moist heat treatment had significantly more bread core moisture (p<0.05). According to the results, dry heat treatment did not affect the texture of bread (p>0.05), while the use of flour obtained from moist heat treatment with a particle size of 180 microns led to the improvement of bread texture by reducing the hardness and chewability (p<0.05). The results of thermal analysis showed that the moist heat treatment sample with a particle size of 180 microns had the lowest enthalpy and was the best sample (p<0.05).
Conclusion
In general, the use of flour with a particle size of 180 microns and moist heat treatment to improve the rheological and staling properties of bread were the best examples.
کلیدواژه‌ها [English]
- Bread quality
- Particle size
- Physical modification
- Wheat flour
©2025 The author(s). This is an open access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0)
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