Abstract
Abstract: In order to evaluate the suitability for fresh-cut vegetable processing of green capsicum, 20 main cultivars of green capsicum in China were collected and planted in greenhouse, and fruits were picked at the similar maturity level. Seventeen indices of the fruits were measured, which included physical and chemical indices (L*, a* and b * value, sensory evaluation score, product yield ratio, fruit hardness, pulp thickness, moisture content, ratio of sugar to acid, soluble solids, titratable acid), and functional indices (vitamin C content, total phenolics content, DPPH free radical scavenging activity (DPPH value), ferric ion reducing antioxidant power (FRAP value), ABTS+·radical scavenging activity (ABTS value) and beta carotene content). Significance analysis of basic measured data was carried out by SAS 9.2. Main evaluation indices were filtered by correlation analysis, principal component analysis and variable cluster analysis. The weight of main evaluation indices were determined by analytic hierarchy process (AHP). The suitability for fresh-cut vegetable processing of the 20 tested green pepper cultivars was appraised by grey relational degree analysis method. The basic data of 17 indices on 20 green pepper cultivars were measured and analyzed. Results of significance analysis showed that all indices varied from one tested green capsicum cultivar to another one excepted for moisture content, and the 3 indices which had the top coefficient of variation were b * value, beta carotene content and FRAP value. Among all the tested 20 cultivars, "Longjiao No. 5" had the highest content of vitamin C, "Jingla No. 2" had the highest content of beta carotene and "Jingyanzhoupila" had the strongest antioxidant capacity. Results of correlation analysis showed that fruit hardness had significantly negative correlation with sensory evaluation score and the correlation coefficient was -0.68, however it had positive correlation with soluble solid content and the correlation coefficient was 0.72. Sugar-acid ratio and titratable acid showed significantly negative correlation and the correlation coefficient was -0.81. Vitamin C content showed positive correlation with FRAP value, ABTS value and total phenol content, and the correlation coefficient was 0.69, 0.73 and 0.58 respectively. Pulp thickness had negative correlation with vitamin C content and total phenol content, and the correlation coefficient was -0.5 and -0.6 respectively. Beta carotene content had significantly negative correlation with L* and b* value and the correlation coefficient was -0.63 and -0.66 respectively. The number of main evaluation indices was determined by principal component analysis, the tested indices at the same level of clustering were divided by variable cluster analysis, and the representative index in each category was decided by factor assessment method; then the 6 indices, including sensory evaluation score, vitamin C content, product yield ratio, ratio of sugar to acid, beta carotene content and total phenol content, were filtered as the main evaluation factors for fresh-cut processing and their weighting was 38.15%, 26.55%, 18.37%, 9.00%, 5.00%, 2.94% respectively, which was determined by APH method. The grey correlation analysis was applied based on above results, and it was found that the best cultivars for fresh-cut processing were "Guofu No. 311" and "Zhongjiao No. 106" for mild spicy green capsicum, "Longjiao No. 6" for spicy green capsicum and "Xingshuzhoupila" for very spicy green capsicum. It is concluded that the collected basic data and the established analysis system can be used for suitability evaluation of fresh-cut vegetable processing, and also provide scientific guidance for green capsicum breeding and breeding of varieties that are rich in functional components.
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