What is the fine-grained topic of the following text: Combined approach of full factorial design and conventional one-factor-at-a-time was applied to obtain optimum degradation at sonication power intensity of 11.5 W cm−2, irradiation time 120 min and 0.1 g L−1 xanthan in a salt-free solution. Only return the topic.
Optimization of xanthan degradation using full factorial design and conventional one-factor-at-a-time approach.