كاربرد روش سطح پاسخ در بهينه‌سازي شاخص‌هاي نيم جوش كردن براي پيش بيني بيشترين راندمان برنج سالم

Application of Response Surface Methodology (RSM) for Optimization of Parboiling Indicators and Prediction of Head Rice Yield

نيم جوش كردن، يك فرآيند هيدروگرمايي است و شامل سه مرحله غوطه‌وري، بخاردهي و خشك‌كردن شلتوك مي‌باشد. در اين تحقيق از روش سطح پاسخ و طرح مركب مركزي براي بهينه‌سازي شاخص‌هاي نيم جوش كردن (دماي غوطه‌وري و زمان بخاردهي) استفاده گرديد. نمونه‌ها بعد از غوطه‌وري (55 ،60، 65 ، 70 و 75 درجه سلسيوس) و بخاردهي (2، 4، 6، 8 و 10 دقيقه)، طي 3 روز تحت شرايط محيطي تا رسيدن رطوبت نهايي به 11% (بر پايه‌تر) خشك‌ شده‌اند. براي هر پاسخ با استفاده از تجزيه رگرسيون خطي چندگانه، مدل‌هاي چندجمله‌اي درجه‌ي دوم به دست آمد. تجزيه واريانس (ANOVA) براي بررسي صحت و دقت مدل برازش شده انجام شد. نتايج نشان داد كه تأثير مربع دماي غوطه‌وري و مربع زمان بخاردهي بر مقدار راندمان برنج سالم معني‌دار (P

Parboiling is a hydrothermal treatment and it consists of 3 steps: soaking, steaming and drying of paddy. In this research RSM and central composite design was used for optimization of parboiling indicators (soaking temperature and steaming time). After soaking temperature of (55, 60, 65, 70 and 75 oC) and steaming time of (2, 4, 6, 8 and 10 min), the samples were dried for three days in the shade to a final moisture content of 11±1% (w.b.). Using multiple regression analysis a quadratic polynomial equation was developed for each response. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The results showed that the effects of soaking temperature and steaming time were found to be significant (p<0.01) with regards to head rice yield. Results also showed that, soaking temperature and steaming time were the most important variables which affect the head rice yield, respectively. Based on developed modeles, optimum conditions for the maximum head rice yield of (66.67%), were achieved at soaking temperature of 64.93oC and steaming time of 6.67 min.