THE PROTEINS DEGRADATION IN DRY CURED MEAT AND METHODS OF ANALYSIS : A REVIEW

摘要

The aim of the review was to find informations about degradation processes in dry cured meat and about infuence of different conditions to them. Drying and curing are the most popular methods used in the meat industry. Many biochemical reaction proceeds within this process and are responsible for its final characteristic texture and flavour properties. Products with a long period of time maturing, show an extensive breakdown of main proteins and the generation of a high number of small peptides. During of drying-ripening procedures by endogenous enzymes produce small peptides and aliphatic acids contributing to the unique flavour of cured meat. These products influences flavour and texture due to the protein degradation to low-molecular weight compounds and free amino acids (FAA) and biogenic amines which influence directly in taste. Proteins in dry-cured meats can be gradually degraded into low molecular mass peptides except for FAA and biogenic amines as histamine, putrescine, tyramine, and tryptamine. The amount of toxic components generated can be assessed by lot of indicators, such as the total volatile basic nitrogen (TVB-N) content, the thiobarbituric acid reactive substances value. Methods for the detection of total volatile basic nitrogen (for the detection TVB-N) contents are normally analytical such as the micro-diffusion method and semi-micro nitrogen determination. The hyperspectral imaging system (HIS) technique coupled with appropriate chemometric multivariate analyses. The low molecular mass peptides (1000 - 2100 Da) arise from both type of muscle proteins indicating that sarcoplasmic and myofibrillar proteins are affected during fermentation and ripening. The analysis of peptide sequences by LC–MS/MS. The identification of the peptides is done by tandem mass spectrometry LC-MS/MS. The fraction with active antioxidant activity is carried out by Acquity HPLC system connected with a reverse phase. The flow entered directly into the MS/MS system for multiple reaction measurement. The method of free amino acids determination is based on several methods. For example reaction of the free amino acids with phenylisothiocyanate to form stable derivatives which are subsequently separated by liquid chromatography. The identification and quantification of amino acids are carried out used a HPLC detector. Simpler method of analyse amino acids and biogenic amines contents. The samples are extracted after reaction with trichloroacetic acid, and the extract is finally filtered through Whatman paper. To remove fat, the extracts are kept at ? 20 °C for 1 day, and then subjected to centrifugation. The supernatant is finally collected and filtered through membrane filters Analyses of free amino acids and biogenic amines are performed using an amino acid analyser equipped with a Watrex Polymer 8 ion exchange column (20 cm long, 3.7 mm i.d.) for amino acids, and an Ostion LG ANB ion exchange column (6 cm long, 3.7 mm i.d.) for biogenic amines. Colorimetric detection is accomplished at 570 and 440 nm, for amino acids and biogenic amines, after post column derivatization (121 °C) with ninhydrin. MALDI-TOF-MS technique of the low-molecular weight compounds analyses is based on analysis on their molecular weight. The proteins and their fractions with known molecular weight can be detected.