Method for determining degree of doneness of sturgeon meat based on flavor fingerprinting and partial least squares (PLS) regression

A method for determining a degree of doneness of a sturgeon meat based on flavor fingerprinting and a partial least squares (PLS) regression, comprising the following steps:

• (1) shaping the sturgeon meat to a fixed size and heating the sturgeon meat at different temperatures at different times to obtain a heated sturgeon meat;
• (2) pulping the heated sturgeon meat in step (1) to obtain a pulped sturgeon meat;
• pipetting 11-15 mL of the pulped sturgeon meat into a first 20 mL headspace vial;
• sealing the first headspace vial;
• equilibrating the first headspace vial at 50-52° C. for 25-30 min;
• inserting an extraction head into the first headspace vial to allow adsorption at a distance of 1-2 cm from a liquid surface for 25-30 min;
• inserting the extraction head into a gas chromatography (GC) injection port desorbing at 235-245° C. for 2 min;
• and conducting a gas chromatography-mass spectrometry (GC-MS) analysis;
• (3) loading 1-5 g of the heated sturgeon meat in step (1) into a second 20 mL headspace vial;
• sealing the second headspace vial;
• incubating the second headspace vial at 45-55° C. for 15-25 min;
• and taking, by a syringe at 80-90° C., 490-510 μL of headspace gas from the second headspace vial for a gas chromatography-ion mobility spectrometry (GC-IMS) analysis;
• (4) measuring a myofibrillar protein content of the heated sturgeon meat in step (1), and calculating a myofibrillar protein extraction ratio indicating a ratio of a myofibrillar protein content of the heated sturgeon meat to a myofibrillar protein content of the sturgeon meat before heating;
• (5) establishing a multivariate linear fit curve by the PLS regression by taking the myofibrillar protein extraction ratio as a response variable and an amount of volatile flavor substances as independent variables, directly comparing characteristic regions of a fingerprint by GC-IMS, and conducting a principal component analysis (PCA);
• and
• (6) determining a degree of doneness of a target sturgeon meat sample by acquiring GC-MS and GC-IMS data of the target sturgeon meat sample, analyzing through the multivariate linear fit curve established in step (5), and comparing characteristic regions of a fingerprint of the target sturgeon meat sample and conducting the PCA according to step (5).