Modeling and Optimization of Ultrasound Assisted Extraction Parameters using Response Surface Methodology for Water Soluble Polysaccharide Extraction from Hazelnut Skin

The aim of this study is to evaluate optimum process conditions for water soluble polysaccharides (WSP) of plant waste materials such as hazelnut skin by using response surface methodologies (RSM). Polysaccharides from hazelnut skin were extracted by means of probe type sonication system using distilled water as a solvent with several sonication time, temperature and amplitude. Response surface models were applied by both Box–Behnken Design (BBD) and Central-Composite Design (CCD) for determining optimal condition which satisfies both maximizing polysaccharide yield and minimizing applied energy for sonication. Results showed that both BBD and CCD models represented the system with high regression coefficient (R2 > 0.95) and optimum conditions are 16.15 min, 45C, 50.29% amplitude with 0.733 desirability, 15.97 min, 45C, 47.27% amplitude with 0.712 desirability, respectively, for designs. Results of given conditions are 1.74% yield and 78.75 kJ consumption for BBD and 1.64% yield and 71.68 kJ for CCD. These results were validated by comparing experimental results at 15 min, 45C, 50% amplitude. As a consequence, it was observed that selected statistical models represent the system with a high accuracy and associating scores of each optimal condition is close enough to experimental results. Practical Applications: Hazelnut skin is accepted as a waste material and there is no known application area in food industry. Although this waste can be utilized as bioactive polysaccharide source, extraction procedure requires enzymatic and chemical treatments. Sonication can be applied to extract water soluble polysaccharide from hazelnut skin and this method can be applied practically for further studies. Because during polysaccharide extraction, sonication improves uniform heat distribution and enhances mass transfer while decreasing activation energy due to the increase in particle velocity, intense mixing, cell disruption and partial hydrolysis. These effects make sonication profitable tool to obtain bioactive polysaccharides from plant waste materials. RSM is an easy way to organize experiments and optimize complex system such as extraction. On the other hand BBD design is easier and more applicable then CCD especially when the process has some concerns such as difficulties to adjust required level of parameters for CCD. © 2016 Wiley Periodicals, Inc