Abstract:
Lonicera caerulea is one of the fruits rich in vitamins, active substances, and minerals for the antibacterial, anti-inflammatory, and antioxidant. The breeding can be relatively late in recent years, leading to the relatively scarce product development for Lonicera caerulea in China. Moreover, Lonicera caerulea can vary outstandingly in its various varieties. There is no systematic evaluation of the quality of Lonicera caerulea at present. This study aims to determine the key indicators of the quality for the systematic evaluation and classification of the different varieties of Lonicera caerulea. Taking 18 varieties of Lonicera caerulea as the research object, some indicators were selected to clarify the differences in 100-grain weight, soluble solid content, moisture, total acid, soluble sugar, sugar-acid ratio, total phenol, total flavonoids, anthocyanin, vitamin C, iron, calcium, sensory evaluation, and pancreatic lipase inhibition rate. A comprehensive evaluation of Lonicera caerulea quality was established by correlation analysis and principal component analysis. 18 varieties of Lonicera caerulea were classified by the heat map clustering analysis, according to the characteristics of various Lonicera caerulea. The potential application direction was also analyzed after the evaluation. The results showed that there were significant differences in each index of different varieties of Lonicera caerulea (P<0.05). The correlation analysis between each index showed that there was a significant positive correlation between the contents of total acids, total phenols, total flavonoids, and anthocyanin (P< 0.05). The inhibition rate of pancreatic lipase was significantly positively correlated with the total acid content (P<0.01), and the anthocyanin content (P<0.05), respectively. The sensory evaluation score was significantly positively correlated with the 100-seed weight (P<0.05). Five principal components were extracted by principal component analysis, where the cumulative contribution rate was 84.524 %. The contents of total acids, total phenols, total flavonoids, anthocyanins, and pancreatic lipase inhibition rate were the key indicators to evaluate the quality of Lonicera caerulea. According to the comprehensive evaluation function, the top five varieties were Serena (42.38), Beilei (41.04), Beleri (39.26), Ulan (35.38), and Charcoal fire (34.56). These five varieties presented excellent quality for the new varieties or directional breeding. The 18 varieties of Lonicera caerulea were divided into I, II, and III groups by the heat map clustering analysis, each containing 4, 5, and 9 varieties. Specifically, type I Lonicera caerulea was suitable for the fresh food, type II Lonicera caerulea was for the developing health food with auxiliary lipid-lowering function, and type III Lonicera caerulea was for the development of leisure food, where the Asori, 1-100-82, 33-11-82 and Blue spindle were suitable for the developing juice, and wine, as well as the soft blue, Iliad, Tomicka, Waxiugang and Charcoal fire were suitable for the processing jam, preserved fruit and canned products. This finding can provide a strong reference for the directional breeding in the development and utilization of different varieties of Lonicera caerulea. A systematic and reliable evaluation can be widely expected to serve as the quality analysis and comprehensive classification of Lonicera caerulea.