摘要
Hawthorn fruit with high citric acid content leads to sour taste,and compacted flesht is not conducive to process into juice.To solve these problems,Leuconostoc citreum,Lactobacillus casei,and Lactobacillus brevis were screened out for compounding,by which the rate of degradation of citric acid reached 81.147%after solid-state fermentation(SSF).Results show that pectin solubility is improved,the cell-wall structure is dissolved and loosened,the fruit becomes softer,and the juice yield is increased to 60.63%,while the surface color is slightly affected after fermentation.Meanwhile pH value of fermented hawthorn fruit grows to 5.05,the content of citric acid reduces to 1.54 mg/kg,and the solidity-acid ratio is increased to 11.55,so sourness and astringency are alleviated and the taste is apparently improved.Additionally,total phenolics and total flavones are released and the antioxidant activity is enhanced by a factor of 1.2-1.6.Besides,the contents of undesirable flavor substances such as acids and sulpho-compounds are reduced in fermented hawthorn fruit,while the content and diversity of flavor substances including esters,phenolics,and aldehydes are increased.This is positive for improving the flavor of hawthorn fruit.Based on the KEGG(Kyoto Encyclopedia of Genes and Genomes)results,it is proven that seven pathways are mainly involved in the fermentative metabolism,in which nine metabolites are produced.Therein,the phenylalanine metabolism pathway involving benzeneacetaldehyde shows the highest enrichment.Therefor,SSF of compound LAB is feasible in improving the processing quality and the suitability of hawthorn fruit.
基金
supported by the Application Foundation Project of Liaoning Provincial Key R&D Program(Approval No.:2023JH2/101300135),which was awarded by Department of Science and Technology of Liaoning Province.
