Abstract:

Objective: To compare the volatile flavor compounds of tuna pancreatic protein hydrolysates produced by different
proteases and therefore to provide references for deep processing of tuna pancreas. Methods: An electronic nose was used to detect
odors of tuna pancreatic tissue as a control and its enzymatic hydrolysates. The sensor array was optimized by loading analysis for
principal component analysis (PCA). Headspace solid-phase micro extraction coupled with gas chromatography-mass spectrometry
(HS-SPME-GC-MS) was used to identify and compare the volatile flavor components of all the above samples. Results: PCA
analysis revealed that electronic nose enabled the detection of significant differences in odors of the control, bromelain, animal
protease, alkaline protease, papain, flavorzyme, trypsin and neutral protease groups. A total of 45, 54, 54, 34, 46, 43, 53 and 50
volatile substances were identified by HS-SPME-GC-MS in these groups, respectively, mainly including hydrocarbons, alcohols,
aldehydes, ketones and furans. The flavor compounds syringaldehyde, β-ionone and 2-ethyl-furan were the most abundant in the
animal-derived protease groups. The relative contents of fishy odor compounds in the papain, flavorzyme and trypsin groups were
lower than those in other groups. Conclusion: The hydrolysis of tuna pancreas with animal-derived proteases could significantly
enhance pleasant flavor. Papain, flavourzyme and trypsin have better effects on deodorization.

Key words: tuna pancreas, proteases, volatile substances, headspace solid-phase micro extraction (HS-SPME), electronic nose, gas chromatography-mass spectrometry (GC-MS)