Different Varieties of Kiwifruit: Analysis of Differences in Quality Indexes and Volatile Components in Juice by Gas Chromatography-Ion Mobility Spectrometry

This study aimed to compare the differences in the sensory (appearance and cross-sectional morphology) and physicochemical characteristics (juice yield, total soluble solids (TSS), total sugars, pH, titratable acids, vitamin C, total phenolics, anthocyanins, flavonoids and tannins) of four different varieties of kiwifruit (Hongyang, Jinyan, Wanzhou Hongxin and Donghong). The fruit quality data were analyzed by principal component analysis (PCA) and cluster analysis (CA), and the volatile aroma compounds of juice samples were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that there was no significant difference in juice yield or total acid content among varieties, and the contents of total sugars, vitamin C, total phenolics, flavonoids, anthocyanins in Wanzhou Hongxin were higher than those in the other varieties, while tannin content was higher in Jinyan than in the other varieties. The results of PCA and CA consistently showed that Jinyan was classified into one group, whereas Hongyang, Wanzhou Hongxin and Donghong were classified into another group. A total of 55 volatile components were detected across four juice samples, and there were significant differences in volatile compounds among these samples. The results of classification by PCA and CA based on volatile components were consistent with those based on quality index.