Quality Evaluation of Celery Based on Principal Component Analysis

In order to improve the celery quality evaluation,14 physiological and biochemical indicators were determined for 13 celery cultivars harvested at suitably editable stage. The correlation among indicators was analyzed and the evaluation model was established using principal component analysis method,and the more comprehensive quality assessment was made. The results showed that there were certain differences in quality,physical and chemical properties among different celery cultivars. There was a significantly negative correlation between a^* value and chlorophyll content(P<0.01). Significantly positively correlations were observed between V_C and petiole firmness(P<0.01),between V_C and chlorophyll and total sugar content,peroxidase(POD)as well as phenylalanine ammonia lyase(PAL)activity(P<0.05). The firmness was significantly positively correlated with total sugar and cellulase activity(P<0.01),total sugar was significantly correlated with the activity of POD(P<0.05)and extremely significantly correlated with the activity of cellulase(P<0.01). Based on principal component analysis,7 key indices as chlorophyll,total sugar,edible rate,PAL activity,firmness,dietary fiber and weight loss rate were extracted from all measured indices,and a comprehensive mathematical model was established as F=0.388F₁+0.238F₂+0.143F₃+0.134F₄+0.098F₅. According to this formula calculation of comprehensive scores and sorting to determine the better quality varieties were "Shandong Red Celery","French Queen","Liangfeng Yuqin","Glass Crisp" and "Huang Xinqin(Yunnan)". The results provides a reference for the quality evaluation and utilization of celery.