AN INFLUENCE OF SPONTANEOUS MICROFLORA OF FERMENTED HORSEMEAT PRODUCTS ON THE FORMATION OF BIOLOGICALLY ACTIVE PEPTIDES

Abstract

At present, different methods are used to accumulate functional peptides in meat raw materials, including the use of spontaneous microflora during autolysis, the use of the microbial enzymes (the application of starter cultures) and the use of the non-microbial enzymes (enzymes of animals and plant origin). Each method has its own specific characteristics of an impact on raw materials, which requires their detail study. This paper examines an effect of spontaneous microflora of fermented meat products from horsemeat on formation of biologically active peptides. Using the T-RFLP analysis, it was established that in air dried and uncooked smoked sausages produced with the use of the muscle tissue of horsemeat as a raw material, a significant proportion of microflora was presented by lactic acid microorganisms. The highest content of lactic acid microflora was observed in sample 1 (52.45 %), and the least in sample 3 (29.62 %). Sample 2 had the medium percent content of microflora compared to samples 1 and 3 — 38.82 %. It is necessary to note that about 25 % of microflora was unculturable; i.e., it had metabolic processes but did not grow on culture media. In the samples, the representatives of Actinobacteria and Pseudomonadales were found. Pathogenic and conditionally pathogenic microflora was not detected. Not only quantitative but also qualitative changes were observed in the studied samples. For example, in samples 1 and 2, the fractions of amilo-1,6-glucosidase, fast-type muscle myosin-binding-protein C; glucose-6-phosphate isomerase; fast skeletal muscle troponin I, phosphoglycerate kinase, pyruvate kinase and skeletal muscle actin were found, which were absent or reduced in sample 3. Therefore, in the studied product, good preservation of the main spectra of muscle proteins was observed, and the identified fractions, apparently, can be sources of new functional peptides. Not only quantitative but also qualitative changes were observed in the studied samples. For example, in samples 1 and 2, the C-terminal fragments of the myosin heavy chain were found, which were absent in sample 3. Also, the significant content of myoglobin was revealed in samples 2 and 3, and the myosin light chain was found in sample 1. Therefore, in the studied product, good preservation of muscle proteins myosin and myoglobin, which can be a source of new functional peptides, was observed. Based on the results of tandem mass-spectrometry, the proteins and natural short peptides present in the analyzed extracts were identified by the obtained masses. They belonged mainly to different peptides of equine myoglobin. Also, we identified several fragments, among which fast skeletal muscle troponin T and muscle creatine kinase were found. The obtained materials can be regarded as an experimental basis for the directed impact of starter cultures with a possibility to predict the protein and peptide composition of a finished product including with the aim of obtaining biologically active peptides.