Comprehensive comparison and analysis of fruit quality indicators of five Ficus carica Linn. varieties

【Objective】This study aimed to evaluate the quality of fig (Ficus carica Linn.) fruits and provide a reference for consumers and breeders for promoting the sustainable development of the fig industry.【Methods】Using the fruits of five main fig varieties, namely Orphan, Banane, Qingpi, Bojihong and Fencahn, as experimental materials, the differences in appearance and internal quality were determined and analyzed, covering 36 indicators such as fruit color difference, soluble sugar, organic acid, fatty acid, amino acid, protein and total phenols, total flavonoids, etc.. A radar chart was also used for comprehensive evaluation.【Results】The results showed that in terms of fruit color difference, the L* and b* values of Orphan were all higher than those of Qingpi, Fencahn, Banane and Bojihong, while the a* value of Qingpi was lower than those of Orphan, Banane, Fencahn and Bojihong. The soluble sugar of the fruits of the five fig varieties was composed of glucose, fructose and sucrose, with glucose and fructose being the main components, accounting for 49.12%-51.22% and 45.23%-46.72% respec-tively. In terms of soluble sugar content, Qingpi had the highest content (173.02 mg · g- 1 ), Orphan had the lowest content (115.22 mg · g- 1 ), and the content of each sugar component on Qingpi was higher than those of Fencahn, Bojihong, Banane and Orphan, and there were significant differences among the varieties. The organic acid of each variety of fig varities was composed of malic acid, quinic acid, succinic acid, shikimic acid and fumaric acid, and the malic acid was the main organic acid, and the proportion of each organic acid among the varieties was significantly different. The proportion of malic acid was 55.65%-74.67%, quinic acid was 18.74%-35.36%, succinic acid was 1.47%-4.49%, shikimic acid was 1.41%-3.77%, and fumaric acid was 0.7%-1.23%. The organic acid content of Orphan was highest (1.43 mg·g-1 ) and Fencahn was lowest (0.69 mg·g-1 ), and the content of each single organic acid was significantly different among the varieties. The content of malic acid (1.07 mg·g-1 ) and shikimic acid (0.3 mg · g-1 ) of Orphan was the highest, the content of quinic acid (0.35 mg · g-1 ) and fumaric acid (0.01 mg · g-1 ) of Bojihong was the highest, and succinic acid (0.05 mg · g-1 ) of Qingpi was the highest. The GC-MS detection revealed that all five fig varieties contained 11 amino acids, namely alanine, serine, glutaric acid, threonine, asparagine, γ-aminobutyric acid, valine, isoleucine, proline, and piperidine acid. The content of each amino acid in different varieties was significantly different, with Banane having the highest content of alanine, serine, glutaric acid, γ-aminobutyric acid and asparagine; Qingpi having the highest content of proline, piperidine acid and threonine; Orphan having relatively higher content of valine, aspartic acid and isoleucine. In contrast, the contents of amino acids of Bojihong and Fencahn were generally lower. The total fatty acid content varied among the varieties, with Fencahn having the highest content of 2 048.44 μg·g-1 and Orphan having the lowest content of 1 652.42 μg·g-1 . Furthermore, the GC- FID test results indicated that the total fatty acids of the five fig varieties were composed of 11 types of fatty acids, namely C14:0, C16:0, C16:1n7, C18:0, C18:1n9, C18:2n6, C18: 3n3, C20:0, C20:1n9, C22:0 and C22:1n9. Each type of fatty acid had significant differences in content and proportion among the different varieties. Among them, Fencahn had the highest content of C14:0, C16:0 and C16:1n7 and Orphan had the lowest ; C18:0, C20:1n9, and all varieties had similar content of C22:1n9 with no significant differences; Bojihong had he highest content of C18:1n9 (234.92 μg · g- 1 ) and Fencahn had the lowest content (186.24 μg · g-1 ); Qingpi had a significantly higher content of C18: 2n6 (426.04 μg·g-1 ) than other varieties; Fencahn had a much higher content of C18:3n3 (301.32 μg·g-1 ) than other varieties; The content of C20:0 in Banane (77.56 μg · g- 1 ) was relatively high and relatively low in Bojihong (34.45 μg·g-1 ); while the content of C22:0 in Qingpi was the highest (45.54 μg·g-1 ), approximately twice as high as the value of Orphan (23.77 μg · g-1 ). In terms of protein, total phenols and total flavonoids, there were also significant differences among the varieties. Among them, the protein content was the highest in Qingpi (8.17 mg·g-1 ), and the lowest in Orphan (4.19 mg·g-1 ). The total phenol content was the highest in Banane (0.51 mg·g-1 ), approximately 2.5 timesas high as the value of Orphan (0.21 mg·g-1 ). The total flavonoid content was the highest in Fencahn and Qingpi (0.43 mg·g-1 and 0.42 mg · g-1 respectively), and the lowest in Orphan and Banane (0.17 mg · g-1 and 0.14 mg · g-1 respectively).【Conclusion】In terms of the overall fruit quality, Qingpi is the best variety, followed by Fencahn, Banane, Bojihong and Orphan.