RESUMO
Introduction: Citrus fruit is considered a superfood due to its multiple nutritional functions and health benefits. Quantitative analysis of the numerous quality characteristics of citrus fruit is required to promote its sustainable production and industrial utilization. However, little information is available on the comprehensive quality assessment of various fruit quality indicators in different citrus cultivars. Methods: A total of nine different fresh citrus fruits containing seeds were collected as the experimental materials. The objectives of this study were: (i) to determine the morphological and juice properties of citrus fruits, (ii) to measure the mineral elements in the peel, pulp, and seeds, and (iii) to evaluate the fruit quality index (FQI) using the integrated quality index (IQI) and the Nemoro quality index (NQI) methods. Results: There were significant differences in fruit quality characteristics, including morphological, mineral, and juice quality, among the investigated citrus cultivars. The proportion of pulp biomass was the highest, followed by that of peel and seeds. N and Cu had the highest and lowest concentrations, respectively, among the measured elements across all citrus fruits, and the amounts of N, P, Mg, Cu, and Zn in seeds, K and Al in pulp, and Ca, Fe, and Mn in peel were the highest, dramatically affecting the accumulation of minerals in the whole fruit and their distribution in various fruit parts. Additionally, Ningmeng fruits had the highest vitamin C and titratable acidity (TA) but the lowest total soluble solids (TSS) and total phenolic (TP) contents, resulting in the lowest TSS/TA and pH values. In contrast, Jinju fruits had the highest TSS and TP contents. Based on the mineral element and juice quality parameters, principal component analysis showed that the citrus fruits were well separated into four groups, and the dendrogram also showed four clusters with different distances. The FQI range based on the IQI method (FQIIQI) and NQI method (FQINQI) was 0.382-0.590 and 0.106-0.245, respectively, and a positive relationship between FQIIQI and FQINQI was observed. Conclusion: Our results highlight the great differences in mineral and juice characteristics among fruit parts, which mediated fruit quality. The strategy of fruit quality assessment using the FQI can be expanded for targeted utilization in the citrus industry.
RESUMO
With the rapid development of nanotechnology, the environmental impact assessment of nanoparticles (NPs) becomes a pressing problem to ensure the environmental safety and human health. However, the roles of CeO2 NPs on the development of crop reproductive system and fruit quality are largely unknown. Herein, strawberry (Fragaria × ananassa Duch.) plants were exposed to CeO2 NPs at 0-115 mg/L. The reduced generation of stolon, increased pollen numbers and germination rate of pollen grains, as well as the elongation of pollen tubes contributed to the enhanced yield of strawberry upon CeO2 NP exposure (6-115 mg/L). Furthermore, the fruit quality was improved by increasing total phenols, vitamin C, amino acids, and protein contents. More importantly, even at 115 mg/L treatment, fruit Ce contents (4.4 mg/kg) did not exceed the Ce mean oral reference dose of humans. Finally, label-free proteomic results disclosed that differentially expressed proteins related to malate were down-regulated, and the differential regulation of sugar-associated proteins suggested the changes in sugar composition. The significantly different expression of ascorbate and glutathione related proteins exhibited the increased antioxidant capacity of fruits. The findings in the present study provide new perspectives for understanding the potential risk posed by NPs in the environment.