# Comparative Study on Physicochemical and Nutritional Qualities of Kiwifruit Varieties
## 4 Conclusions  
In this study, we estimated pectin, moisture, chlorophyll, carotenoid, flavonoid, energy, carbohydrates, protein, lipid, dietary fiber, soluble sugar, organic acid, vitamin and aroma compound contents according to flesh color and species in kiwifruits. The physical and chemical properties, nutritional properties and aroma varied in different flesh color and species groups. Red-fleshed kiwifruits had the highest sugar:acid ratios and total flavonoid contents, which led to a particularly sweet flavor and a bright red color. However, the energy and carbohydrate contents were much higher in red-flesh kiwifruits, and lipid and dietary fiber contents were lower in red-fleshed kiwifruits than yellow- and green-fleshed kiwifruits. The green- and yellow-fleshed kiwifruits with low energy and carbohydrates were suitable for people with \"three highs\" and poor stomachs. VE and VB1 contents were high in red-fleshed kiwifruits. Generally, green-fleshed kiwifruits, such as _A. eriantha_, had the highest chlorophyll a content and chlorophyll b content. Interestingly, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**PCA** & **Eigenvalues** & \
\begin{tabular}{c} **Variance Contribution Rate** \\ **(\%)** \\ \end{tabular} &
\begin{tabular}{c} **Cumulative Variance** \\ **Contribution Rate (\%)** \\ \end{tabular} \\ \hline
1 & 5.51 & 50.07 & 50.07 \\
2 & 2.07 & 18.86 & 68.93 \\
3 & 1.22 & 11.05 & 79.98 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Eigenvalue and contribution rate of principal components. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Quality Indicators** & \multicolumn{3}{c}{**PCA**} \\ \cline{2-4}  & **1** & **2** & **3** \\ \hline Chlorophyll & 0.95 & 0.16 & 0.01 \\ Carotenoids & 0.73 & \(-\)0.11 & 0.15 \\ Flavonoids & \(-\)0.81 & 0.44 & 0.13 \\ Energy & \(-\)0.13 & 0.80 & 0.37 \\ Protein & \(-\)0.22 & \(-\)0.13 & 0.80 \\ Lipid & 0.87 & 0.25 & 0.20 \\ Dietary Fiber & \(-\)0.39 & \(-\)0.58 & 0.32 \\ Soluble Sugars & \(-\)0.56 & 0.77 & 0.07 \\ Organic Acids & 0.95 & 0.23 & \(-\)0.05 \\ VC & 0.93 & 0.30 & \(-\)0.07 \\ Pectin & 0.61 & \(-\)0.25 & 0.50 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The component matrix after the principal component is rotated on each quality index. the total carotenoid content of _A. eriantha_ was also the highest in all species, as was the total carotenoid content. The commercial varieties are _A. chinensis_ and _A. chinensis_ var. _deliciousa_, and the protein contents of fruits belonging to these two species were higher than those in other species. A characteristic aroma for red-fleshed kiwifruits were identified; moreover, the specific aroma of 'Jinyan' was narrowed down to being due to n-hexaldehyde and 2-hexenal. The 14 varieties were ranked by principal component analysis, 'Huate', 'MHYX', 'Jinkui' and 'Xuxiang' were the top four highest-ranking varieties. Therefore, we can focus our attention on 'MHYX' and 'Huate' and vigorously make use of their nutritional value to provide processed kiwifruit products. In addition, 'Jinkui' and 'Xuxiang', as major commercial cultivars, should be further actively promoted. This study facilitates selecting kiwifruits for consumers and provided scientific evidence for kiwifruit processing and utilization. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/foods12010108/s1](https://www.mdpi.com/article/10.3390/foods12010108/s1)]([https://www.mdpi.com/article/10.3390/foods12010108/s1](https://www.mdpi.com/article/10.3390/foods12010108/s1)), Figure S1: Contents of pectin (A,B) and moisture (C,D); Figure S2: Contents of chlorophyll a, chlorophyll b, total carotenoid and total flavonoids; Table S1: Quality prediction and evaluation results of 14 kiwifruits. Conceptualization, C.Z. and Q.Z. ; methodology, J.F., X.Y. and F.L. ; validation, H.Z. and X.Y. ; formal analysis, X.Y. and Q.Z. ; investigation, X.Y., H.Z. and J.L. ; resources, Q.Z. and C.Z. ; writing--original draft preparation, X.Y. and Q.Z. ; writing--review and editing, Q.Z. and C.Z. ; visualization, X.Y.