Performance of an autochthonous meat starter culture in a beaker sausage model during ripening using traditional and proteomic approaches

LÓPEZ, CONSTANZA MARÍA; VIGNOLO, GRACIELA; FADDA, SILVINA

San Miguel de Tucuman

Simposio; IV International Symposium on Lactic Acid Bacteria: Food, Health and Applications; 2013

CERELA-CONICET

Lactic acid bacteria (LAB) and Coagulase negative, Gram positive Cocci (CGC) such as Staphylococcus and Kocuria, are the two main groups involved in fermentation of dry cured sausages. Although it is still unknown which bacterial group play the major role in aroma development, two major reactions occur: pH decrease due to the acidogenic metabolism of LAB and nitrate reduction by CGC. The characteristic taste and aroma of fermented sausage are due to many different non-volatile and volatile compounds, some of them originated from added spices while others derived from carbohydrates, proteins and lipids degradation by bacteria during ripening. Meat proteolysis has been widely studied and the contribution of some peptide fractions from the degradation of meat proteins to flavour was generally accepted. Food peptidomic is a new emerging science area which can contribute to reveal the sequences of the complex mixture of peptides (peptidome) of sausages which remain unexplored up to now. This work aimed at the characterization of the resulting peptidome from the fermentation a model beaker sausage (BS) inoculated with an autochthonous well characterized starter culture containing Lactobacillus curvatus CRL705 and Staphylococcus vitulinus GV318. The role of muscle enzymes, L. curvatus (alone) and the starter culture in peptidogenesis was distinguished. Mass spectrometry (MS) analysis of the low molecular weight (LMW) peptide fraction were performed at two incubation times (t=0 and t=10 days) in both BS + L. curvatus and BS + starter culture, and BS control (sterile system added with antibiotic). Proteolysis was evidenced by an intense generation and breakdown of LMW peptides in each model after ripening and the action of LAB and starter culture was revealed by an increased diversity of peptides. In fact, the greatest peptide diversity derived from sarcoplasmic proteins, while a lower contribution of myofibrillar proteins was observed. The origin of proteolytic activity (muscle or bacterial) was stated by the analysis of cleavage sites of known muscle enzymes. L. curvatus (single culture) and starter culture (mixed culture) promoted the hydrolysis of some myofibrillar proteins due to their own peptidases. Also, an increased endogenous proteolysis was evidenced in the presence of L. curvatus due endogenous enzymes activation in the acidic environment. These results establish the baseline to find out the role of peptides on fermented sausage flavor and clearly provide new data about the role of starter cultures on meat proteolysis. In addition, certain set of peptides may be used as biomarkers for the presence of the specific functional cultures, thus contributing to product authentication.