Abstract:

To enhance the added value of jackfruit and enrich the varieties of fruit vinegar in the market, the fermentation process of jackfruit vinegar was optimized, and the aroma components in the finished products were analyzed. The effects of inoculation volume, fermentation temperature, ethanol concentration, and pH on the acetic acid production in jackfruit vinegar were firstly studied through single factor tests, and the optimal fermentation process was obtained by the response surface methodology with four factors and three levels. The results showed that the optimum fermentation parameters were determined as acetic acid bacteria inoculation volume of 11%, fermentation temperature of 32 ℃, ethanol concentration 5%, and initial pH 3.3. Under the conditions, the acetic acid content in the vinegar reached (44.20±0.41)g/L. The aroma components of jackfruit vinegar were determined by head space solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). A total of 67 aroma substances were identified from the jackfruit vinegar. The major aroma compounds were acetic acid (26.15%), isoamyl acetate (12.78%), isoamylol (11.01%), ethyl 2-phenylacetate (10.99%), phenylethyl alcohol (4.72%), decanoic acid (3.61%), benzaldehyde (3.34%), phenethyl acetate (3.12%), octanoic acid (3.08%), 3-methylbutanoic acid (1.31%), ethyl laurate (1.07%). Through the optimization of the fermentation process of jackfruit vinegar and the analysis of aroma components, a new type of fruit vinegar which conforms to the relevant national and industrial standards was prepared, and the aroma components in fruit vinegar were preliminarily identified.

Key words: jackfruit vinegar, fermentation process, response surface method, aroma components, head space solid- phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS)