Study On Flavor Components In The Autolysates Of Penaeus Vannamei Shrimp Head

Shrimp head of Penaeus vannamei is rich in protein and has complete amino acids. It is especially rich in amino acids which are responsible for umami taste and sweet taste.So it is a good raw material for developing novel seafood flavoring. The flavor of autolysates of Penaeus vannamei's head was studied in this paper, using methods including HPLC, gas chromatography, solid phase microextraction, GC-MS spectrometry and sensory evaluation. The purpose of this paper was to provide theoretical basis for developing novel high quality seafood flavoring. The main contents are as follows:1. The basic taste-active components in autolysates of Penaeus vannamei's head were analysed by automatic amino acid analyzer, HPLC and atomic absorption spectrophotometry. Results showed that: (1) the content of free amino acids was high, reaching 9300mg/L. The content of umami-taste amino acids(Asp,Glu) and sweet-taste amino acids(Pro,Gly,Ala) was 2500mg/L, accounting for 26.88% of the total free amino acid content. (2)among nucleotide and nucleotide-related compounds, the content of inosine monophosphate(IMP) was 6.12mg/L;(3)as for inorganic ions, the content of Na+, K+, Cl- was 663.7mg/L,182.1mg/L and 417.2mg/L,respectively;(4) the contents of betaine,lactic acid and succinic acid were 2400mg/L,15.27mg/L and 13.32mg/L,respectively. All these substances not only constituted the main body of taste-active components of the autolysate , but also affected the flavor of the autolysate via synergistic effect.2. By ultrafiltration, macroporous resin and sensory evaluation,the characteristic of umami-taste peptide in autolysates of Penaeus vannamei's head was studied preliminarily. Results were: (1)Using ultrafiltration membrane with interception of 8000Da,5000Da,1000Da to filtrate shrimp head autolysate ,5000Da-1000Da component had the highest content of peptide nitrogen(12.86mg/mL).The taste of this component was proved by sensory evalution to be the most delicious. HPSEC analysis showed that molecular weight of autolysate mostly concentrated between 3000-1000Da. (2) by static adsorption and desorption experiment, setting absorption capacity and desorption rate as indices, optimal macroporous resin for separating taste-active peptides in shrimp head autolysate, optimal separate condition, optimal sample concentration and optimal sample flow rate were determined. They were XAD-16, ethanol-water mixed solution, 0.5 mg/mL and 1.0mg/min, respectively.(3) using macroporous resin to separate taste-active peptide, component eluted by 30% ethanol got the highest score in sensory evaluation. Content of amino acids responsible for umami taste was 35.71g/100g,accounting for 36.11% of the total content of amino acids. 3. Volatile components in autolysates of Penaeus vannamei's head were studied.(1) By applying headspace solid phase microextraction(HS-SPME) combined GC-MS technology,45 and 52 kinds of volatile compounds were separated and identified by analyzing the original solution and the autolysates of Penaeus vannamei's head, respectively. Alkanes had the highest content in both original solution and the autolysate,accounting for 31.46% and 42.16%,respectively;(2)After autolyzing, both total amount and content of compound changed. Especially, the amount of nitrogen or sulphur compounds such as pyridine, pyrrole and pyrazine increased. Aldehydes got the greatest change in content, increasing from 6.39% to 36.45%. These volatile components played an extremely important role in contributing to the flavor of the autolysates of Penaeus vannamei's head.