تاثير امواج فراصوت بر استخراج قند و خواص مكانيكي چغندرقند

The Effect of Ultrasonic Waves on Sugar Extraction and Mechanical Properties of Sugar Beet

شكر يكي از مواد غذايي مهم مورد نياز، به‌طور عمده از چغندرقند و نيشكر به دست مي آيد. با توجه به اهميت شكر، سطح كشت قابل توجه محصول چغندرقند و نيز تعدد كارخانجات صنايع قند و شكر در كل استان هاي خراسان، انجام تحقيقات به منظور دستيابي به راه كارهايي جهت افزايش راندمان استخراج قند ضروري است. در اين تحقيق تاثير فركانس امواج فراصوت، دما و زمان موج دهي بر روي خواص مكانيكي و ميزان استخراج قند از چغندرقند با رطوبت پايه 75% مورد بررسي قرار گرفت. بدين منظور توسط يك دستگاه حمام فراصوت در مقياس آزمايشگاهي، تاثير فاكتورهاي فركانس (بدون موج دهي، 25 و 45 كيلوهرتز)، دما (25، 50 و 70 درجه سانتي گراد) و زمان موج‌ دهي (10، 20 و30 دقيقه) بر روي نمونه‌ها مطالعه گرديد؛ و با نمونه شاهد مقايسه شد. نتايج نشان داد كه فاكتورهاي فركانس، دما و زمان تاثير معني داري بر افزايش استخراج قند داشته است و مي تواند نسبت به نمونه شاهد راندمان قندگيري را تا 56% افزايش دهد. ميزان مدول الاستيسيته و مدول برشي روند كاهشي داشتند. ميزان انرژي كل گسيختگي، انرژي كل برشي، نيروي حداكثر گسيختگي و نقطه تسليم گسيختگي روند افزايشي داشتند. فركانس بر روي نقطه تسليم برشي و نيروي برشي تاثير معني داري نداشت.

Sugar, which can be extracted from sugar cane and sugar beet, is one of the most important ingredients of food. Conducting more research to increase the extraction efficiency of sugar is necessary due to high production of sugar beet and its numerous processing units in northern Khorasan province. In this research, the effect of temperature, time and the frequency of ultrasonic waves on mechanical properties of sugar beet and its extraction rate of sugar in moisture content of 75% were studied. In this regard, an ultrasonic bath in laboratory scale was used. The studied parameters and their levels were frequency in three levels (zero, 25 and 45 KHz), temperature in three levels (25, 50 and 70 ° C) and the imposed time of ultrasonic waves in three levels (10, 20 and 30 min). Samples were prepared using planned experiments and the results were compared with control sugar beet samples. A Saccharimeter was used to measure the concenteration of sugar in samples. Two different types of probe including semi-spherical end and the other one with sharpened edges were used to measure mechanical properties. The studied parameters of frequency, temperature and time showed significant effect on sugar extraction and their resulted effect in optimized levels revealed up to 56% increase in sugar extraction compared with control samples. The obtained values of elastic modulus and shear modulus showed a decreasing trend. The obtained values of total energy of rupture, the total energy of shear, the maximum force of rupture, and the yield point of rupture showed an increasing trend. The frequency had no significant effect on the yield point of rupture and shear force.