J.M. Fresno

Technological characterization of lactic acid bacteria isolated from Armada cheese (a Spanish goats’ milk cheese)

Thirty-one strains of lactic acid bacteria (LAB) isolated from Armada cheese, Sobado variety, (eight strains of Lactococcus lactis subsp. lactis, four strains of Lactococcus lactis subsp. cremoris, two strains of L. lactis subsp. lactis biovar. diacetylactis, two strains of Leuconostoc mesenteroides subsp. mesenteroides, two strains of Leuconostoc mesenteroides subsp. dextranicum, five strains of Lactobacillus plantarum, six strains of Lactobacillus casei subsp. casei and two strains of Lactobacillus brevis) were screened for their acidifying capacity and enzymatic activity, that included the rapid API-ZYM system, the proteolytic activity, the amino-, di-, and carboxypeptidase activity and the caseinolytic activity. The strains of L. lactis subsp. lactis exhibited the highest acidifying and proteolytic activity. Lipase and esterase activity was practically non-existent for lactococci and lactobacilli; a certain esterase activity was observed among leuconostoc. The highest aminopeptidase activity was demonstrated by the cell-free extract (CFE) of some strains of L. plantarum, L. casei subsp. casei and L. mesenteroides subsp. dextranicum. The CFEs of L. lactis subsp. cremoris and L. lactis subsp. lactis possessed carboxypeptidase and dipeptidase activities, at levels depending on the strain. Appreciable caseinolytic activity was detected for the CFE of L. plantarum and those some lactococci.

Characterization of Prato cheese, a Brazilian semi-hard cow variety: evolution of physico-chemical parameters and mineral composition during ripening

Abstract The evolution followed by the overall chemical composition, physico-chemical parameters and the main mineral and trace elements during the ripening of 18 batches of artisanal Prato cheese was studied. This cheese is characterised for its high total solids values (69.15±3.79 g/100 g), as well as low NaCl values (1.03±0.56 g/100 g) which were lower than those described for the majority of other cows milk cheeses studied. Its lactose content disappeared after the first month of ripening, without observing any significant variations in pH values during ripening. The Ca, P, Zn and Mn contents showed a significant decrease ( p

Picón Bejes-Tresviso blue cheese : an overall biochemical survey throughout the ripening process

The gross and mineral composition, the main physico-chemical parameters, the proteolysis (classical nitrogen fractions and free amino acids) and the lipolysis (acidity index of the fat and free fatty acids) were studied throughout the ripening of three batches of Picon Bejes-Tresviso cheese, a Spanish blue-veined variety. The gross and mineral composition and the physico-chemical parameters do not differ very much from those observed in other Spanish and European blue cheeses. From the figures of the different nitrogen fractions it can be concluded that this cheese undergoes an extensive and profound proteolysis throughout the ripening period. Consequently high levels of total free amino acids were observed; the most abundant amino acids at the end of ripening were valine, leucine, lysine, phenylalanine and glutamic acid. Picon Bejes-Tresviso cheese also undergoes an intense lipolysis throughout ripening as the acidity index of the fat and the total free fatty acids values indicated; the most abundant free fatty acid was oleic, followed by palmitic and myristic acid.

Enzymatic activity of lactic acid bacteria (with antimicrobial properties) isolated from a traditional Spanish cheese

Twenty-four strains of lactic acid bacteria (LAB) isolated from a traditional Spanish cheese (Genestoso cheese) were evaluated for their enzymatic activities (acidifying and proteolytic abilities and carboxypeptidase, aminopeptidase, dipeptidase, caseinolytic and esterase activities), in order to select indigenous strains of technical interest for the manufacture of cheese. These strains were selected on the basis of their antimicrobial activity relative to five reference strains and were identified as Lactococcus lactis subsp. lactis (thirteen strains), Leuconostoc mesenteroides (two strains), Leuconostoc pseudomesenteroides (one strain), Lactobacillus paracasei (two strains), Lactobacillus plantarum (one strain) and Enterococcus faecalis (five strains). Lactococcus strains were those that showed the greatest degree of acidifying and proteolytic activity. The cell-free extracts (CFE) of L. paracasei exhibited the highest level of aminopeptidase activity. The highest level of caseinolytic activity was shown by the CFE of one strain of L. lactis. High values were also obtained with the CFE of Lactobacillus and of several Leuconostoc. The highest level of dipeptidase activity was found amongst the strains of L. lactis. Carboxypeptidase activity was generally very low or undetectable for the majority of strains. The greatest degree of esterolytic activity was detected for Enterococcus.

Survival of Enterobacteriaceae during processing of Chorizo de cebolla, a Spanish fermented sausage

Chorizo de cebolla is a popular semi-dry fermented sausage from Galicia (NW of Spain). The survival of Enterobacteriaceae was investigated in three batches of C. de cebolla (one of them hand made and the other two manufactured industrially). The maximum count of Enterobacteriaceae was obtained in each lot after 2 days of the raw sausage mix being stuffed and from then on it started to decrease until it disappeared in the fourth week of ripening in one of the batches manufactured industrially and after 6 weeks in the other. In the artisanal sausages the counts practically decreased exponentially until the third week of ripening, increasing in the following week before again decreasing until the end of ripening, though they never disappeared. Escherichia coli, Serratia odorifera and Enterobacter intermedius were the only species isolated during the curing process of the hand made sausages, E. coli being the dominant species. In the industrial ones a higher number of species were isolated, with the predominance of E. coli and Hafnia alvei.

Characterization and biochemical changes during the ripening of a Spanish craft goat's milk cheese (Armada variety)

The gross and mineral composition, and some physico-chemical parameters were determined in 15 batches of Armada goats milk cheese (a Spanish craft variety), as well as in the milk used for its manufacture. Some biochemical changes during the ripening process have been also investigated. The milk used in the elaboration of Armada cheese had higher lactose, fat, protein and ash contents than previously reported by other authors, whilst iron content was lower than recent results for goats milk from other countries. Armada cheese showed a high total solids content and a low NaCl and ash content. Water activity (Aw) values decreased progressively during ripening, reaching very low final values (0.895 on average). Lactose disappeared almost completely within the first 7 days of ripening, when the cheese had the lowest pH values (about 4.50). l-Lactic acid dominated in the curd, but during the ripening process both isomers (d- and l-) tended to balance. Variations in mineral content during ripening were only found for magnesium, calcium, phosphorus and zinc: they showed a significant reduction in the first days of ripening coincidental with a decrease in pH values.

Proteolytic and lipolytic changes during the ripening of a Spanish craft goat cheese (Armada variety)

The proteolytic ad lipolytic changes during the ripening process were investigated in four batches of Armad goats milk cheese (an artisanal variety produced in the North of Spain), by determining the classical nitrogen fractions, caseins and their degradation products, free amino acids, as well as the acidity of the fat, thiobarbituric aicd number and free fatty acids

Peptidomic study of Spanish blue cheese (Valdeón) and changes after simulated gastrointestinal digestion.

It is increasingly evident that digestion can affect the biological activity of cheese by the release of new active peptides from their precursors or, on the contrary, giving rise to fragments without activity. The characterization of the peptidome of a Spanish blue cheese, Valdeón, has been conducted before and after gastrointestinal digestion, and the digests have been compared to those obtained from pasteurized skimmed milk powder (SMP) using a bioinformatics platform. Peptidomic profiling of digests revealed several regions that are especially resistant to digestion (among them β‐casein 60–93, 128–140, and 193–209). Some of them correspond to well‐conserved regions between species (human, cow, sheep, and goat) and include peptide sequences with reported bioactivity. The great peptide homology found between both digests, cheese and SMP, suggests that the gastrointestinal digestion could bring closer the profile of products with different proteolytic state. Although most of the biologically active peptides found in cheese after digestion were also present in SMP digest, there were some exceptions that can be attributed to the absence of the relevant precursor peptide before digestion.

Microbiological and physico-chemical changes in Genestoso cheese, a Spanish acid curd variety, throughout ripening

Abstract The aim of this work was to study the microbiological and physico-chemical changes in four batches of Genestoso cheese (two ripened in autumn–winter and the other two in spring–summer) throughout manufacture and ripening. In general, the pH decreased more quickly in the cheeses manufactured in spring which, moreover showed values lower in aw and higher in salt/moisture content. The highest counts of aerobic mesophilic bacteria, presumptive lactococci and presumptive leuconostoc were reached in 2 day old cheeses. Lactobacilli and fungic flora became predominant with ripening. The counts of enterococci differed between the batches, but in general the maximum counts in kanamycin aesculin azide were obtained after ripening for 2 or 7 days. The counts on mannitol salt agar were very low and disappeared in the first days of ripening. Enterobacteriaceae were not detected after 15 days of ripening in the cheeses manufactured in spring nor in the 7 day old cheeses of an autumn batch.

Characterization and biochemical changes during the ripening of a Spanish hard goat cheese

Abstract This paper studies the basic composition and principal physicochemical properties of Valdeteja goat cheese, a hard variety made by artisanal procedures in the north-west of Spain. Biochemical changes during the ripening process have also been investigated. This cheese shows a high content of total solids (72·53 ± 7·46%) and in fat (59·50 ± 2·08%), and a low pH value (4·50 ± 0·20). Changes throughout ripening are mainly due to transformation reactions of carbohydrates. Almost 65% of lactose was hydrolysed in the curd, around 80% after ten days and 100% on day 17. The d + l lactate content increased quickly in the first five days. Lipids and nitrogen compounds are not degraded much.