Metabolomic Analysis of Canarium album Fresh Food Quality Differences Based on Sensory Evaluation
[Objective]This study aimed to identify key metabolites that influence the quality of fresh Chinese olives and to investigate the metabolic mechanisms underlying quality differences.[Method]Four Chinese olive varieties were selected as test materials,with Huiyuan as the topgrafting rootstock.The quality of the fruits was evaluated through sensory evaluation.Metabolite identification and analysis of the KEGG pathway were conducted using ultra-high-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS),and the metabolic changes during the ripening process of the fruits were investigated too.[Result]The results of sensory evaluation of four varieties(lines)of Chinese olive fruits showed significant differences in quality.Tianlan No.1 and Dongshan Changsui exhibited good quality,while Huiyuan and Ziyang No.1 had poor quality.A total of 651 metabolites belonging to 15 types were identified in the Chinese olive fruits of the four varieties(lines).Among these,277 were primary metabolites of 6 types,and 365 were secondary metabolites of 9 types.Using variable projection and multiple differences,26 characteristic differential metabolites that influence the quality of fresh Chinese olives were screened.These metabolites included amino acids and their derivatives(6),organic acids(2),lipids(2),and phenolic compounds(16).The phenolic compounds consisted of phenolic acids(3),flavonoids(3),flavonols(2),flavanols(3),and hydrolyzed tannins(5).A metabolic network were established based on the ripening process of Chinese olives to explain the differences in fresh food quality.Chinese olives with good fresh food quality showed a higher accumulation in the biosynthetic metabolic pathway of L-Asparagine and N,N-dimethylglycine,which influenced the taste of fresh food and its resilience.On the other hand,Chinese olives with poor fresh food quality exhibited relatively high levels of hydrolyzed tannins(digalloylchebuloylglucose,galloyl methyl gallate,heterophylliin A),flavonol[morin-3-O-xyloside,quercetin-3-O-(6′-galloyl],Flavan-3-ol[7-O-galloyltricetiflavan,catechin-(7,8-bc)-4α-(3,4-dihydroxyphenyl)-dihydro-2-(3H)-one,catechin-(7,8-bc)-4β-(3,4-dihydroxyphenyl)-dihydro-2-(3h)-one]in the synthesis pathway,which influenced the taste of fresh food and contributed to its bitter taste.[Conclusion]The differences in fresh quality of different olives were closely related to the accumulation differences in amino acid and its derivative synthesis pathways,as well as the synthesis pathways of hydrolyzed tannins,flavanols,and flavan-3-ol during their ripening process.