Crescenza Cheese Research Articles

Physicochemical and rheological characteristics of Crescenza cheese made with 40% of recombined milk during manufacture and storage

The impact of using recombined milk (RM) at 40% compared with 100% fresh milk (FM) was studied in the manufacture and storage of Crescenza cheese. In cheesemaking, no relevant technological differences were detected between FM and RM cheeses, although use of the latter resulted in a slightly more yellowish colour than FM cheeses. During shelf life, RM cheeses showed significantly lower amounts of expressible serum than FM cheeses. Rheological analysis and the hydrolysis of the main proteins followed a similar trend over time. However, glycated proteins were only detected in RM cheeses. Low‐field 1H T2 nuclear magnetic resonance analysis showed a reduction of relaxation times in RM cheeses during storage.

Characterization and pre-industrial validation of Streptococcus thermophilus strains to be used as starter cultures for Crescenza, an Italian soft cheese

The aim of this work was to search for new candidate strains to be included in a culture for Crescenza, a rindless soft cheese, today produced mainly at industrial level using selected starter cultures composed of S. thermophilus. Performance testing was applied to 29 pre-selected strains and a scoring approach was developed to identify the most suitable candidates to be employed in Crescenza cheesemaking. Eight S. thermophilus strains fulfilling most of the desired properties (e.g., high phage resistance, fast acidification rate, no growth below 20 °C, NaCl sensibility, no post acidification at 4 °C) were selected. These strains were grouped in pairs to design different starter culture formulations, which were preliminary tested for the production of Crescenza cheeses at laboratory scale. Two couples of binary cultures (designed Phage rotation 1 and Phage rotation 2) were finally designed and used as starters in pilot scale cheesemaking. The combinations, especially those designed in Phage rotation 1, appeared to be suitable for Crescenza production and showed mutual similarity in terms of strain characteristics, technological performance, and cheese quality. The selection method and ranking approach presented in this work may be adapted to other species of LAB showing traits of industrial interest.

Effect of fermentation-produced camel chymosin on quality of Crescenza cheese

Quality properties of Crescenza cheese, a typical Italian soft cheese with a short shelf life, are negatively affected by proteolysis due to residual rennet activity, causing a bitter taste and excessive softening of its structure. Chemical composition, textural, rheological and sensory properties of Crescenza cheese manufactured with a fermentation-produced camel chymosin (FPCC) were compared with Crescenza cheese obtained with calf rennet during a 3-week shelf life period. Both Crescenza cheeses complied with the overall expected cheese quality. FPCC Crescenza cheese was characterised by a slightly higher moisture content and lower rate of hydrolysis of αS1-casein than Crescenza cheese obtained with calf rennet. However, FPCC cheese showed a slightly firmer body. The use of FPCC as clotting enzyme may be a valid alternative to calf rennet to prevent the defect of excessive cheese softening.

Spatiotemporal Characterization of Texture of Crescenza Cheese, a Soft Fresh Italian Cheese

Crescenza cheese is a soft fresh cheese without rind, typically manufactured using a high amount of rennet. It is characterized by a fast proteolysis that causes changes in texture and leads to the so-called defect of “colatura” that is the tendency of the matrix to freely flow in the outer part of the cheese and generate spatial inhomogeneities into the cheese. In this paper, the textural properties of Crescenza were evaluated for cheeses manufactured using two types of rennet and starter cultures. Cheese texture was monitored during a 3-week shelf life considering a possible spatial variability of the matrix. At the beginning of the shelf life, a certain spatial inhomogeneity was observed from the center to the edge of the cheese block for all the trials. The firmness decreases from the center to the outer part of the block. During storage, hardness showed a decrease during 1st wk of storage; moreover, from days 7 to 21, cheese increased its hardness in the center and decreased it in the outer part of the block, resulting in a higher spatial inhomogeneity of the cheese. The textural measurements can be a useful tool to define the quality of Crescenza cheese during shelf life.

Application of next generation semiconductor based sequencing for species identification in dairy products

In this study, we applied a next generation sequencing (NGS) technology (Ion Torrent) for species identification based on three mitochondrial DNA (mtDNA) regions amplified on DNA extracted from dairy products. Sequencing reads derived from three libraries, obtained from artificial DNA pools or from pooled amplicons, were used to test the method. Then, sequencing results from five libraries obtained from two mixed goat and cow milk samples, one buffalo mozzarella cheese, one goat crescenza cheese and one artisanal cured ricotta cheese, were able to detect all expected species in addition to undeclared species in a few of them. Mining generated reads it was possible to identify different dairy species mitotypes and the presence of human DNA that could constitute a potential marker to monitor the hygienic level of dairy products. Overall results demonstrated the usefulness of NGS for species identification in food products and its possible application for food authentication.

Effect of acidic conditions on fatty acid composition and membrane fluidity ofEscherichia coli strains isolated from Crescenza cheese

The effect of low pH on minimum pH, growth kinetics and adaptive response to acidity conditions were studied on nineEscherichia coli strains having food origin and two collection strains. Moreover, the effects of low pH on the modification of fatty acid (FA) composition and membrane fluidity of the strains were studied. Also the effects of a pre-adaptation to pH 5 on acidic resistance and FA composition were considered. The results showed the crucial role of unsaturated FA in acid adaptation ofE. coli. Cyclization and isomerization of membrane FA represented the most interesting response to acidic growth conditions in theE. coli strains considered. In particularcis/trans isomerization was shown to play an important role in modulating membrane composition and fluidity under acidic conditions. Only one strain was able to adapt to acidic stress increasing its ability to grow at low pH. It responded to pH decrease, conversely to each other strain, by increasing its membrane fluidity at the lowest pH values considered. The results obtained showed that the determination of membrane fluidity in intact whole cells by fluorescence polarisation can represent a useful tool to study instantaneous stress-induced membrane fluidity modifications.

Probiotic Crescenza Cheese Containing Lactobacillus casei and Lactobacillus acidophilus Manufactured with High-Pressure Homogenized Milk

High-pressure homogenization (HPH) is one of the most promising alternatives to traditional thermal treatment of food preservation and diversification. Its effectiveness on the deactivation of pathogenic and spoilage microorganisms in model systems and real food is well documented. To evaluate the potential of milk treated by HPH for the production of Crescenza cheese with commercial probiotic lactobacilli added, 4 types of cheeses were made: HPH (from HPH-treated milk), P (from pasteurized milk), HPH-P (HPH-treated milk plus probiotics), and P-P (pasteurized milk plus probiotics) cheeses. A strain of Streptococcus thermophilus was used as starter culture for cheese production. Compositional, microbiological, physicochemical, and organoleptic analyses were carried out at 1, 5, 8, and 12 d of refrigerated storage (4°C). According to results obtained, no significant differences among the 4 cheese types were observed for gross composition (protein, fat, moisture) and pH. Differently, the HPH treatment of milk increased the cheese yield about 1% and positively affected the viability during the refrigerated storage of the probiotic bacteria. In fact, after 12 d of storage, the Lactobacillus paracasei A13 cell loads were 8 log cfu/ g, whereas Lactobacillus acidophilus H5 exhibited, in P-P cheese, a cell load decrease of about 1 log cfu/g with respect to the HPH-P cheese. The hyperbaric treatment had a significant positive effect on free fatty acids release and cheese proteolysis. Also, probiotic cultures affected proteolytic and lipolytic cheese patterns. No significant differences were found for the sensory descriptors salty and creamy among HPH and P cheeses as well as for acid, piquant, sweet, milky, salty, creamy, and overall acceptance among HPH, HPH-P, and P-P Crescenza cheeses.

Acid adaptation and survival of Listeria monocytogenes in Italian-style soft cheeses

The ability of Listeria monocytogenes to survive and grow at high salt concentrations and low pH makes it a potential hazard after the consumption of milk and dairy products, often implicated in severe outbreaks of listeriosis. This study was designed to evaluate the behaviour of L. monocytogenes in traditional acid and salted Italian-style soft cheeses and to investigate whether Listeria occurrence and growth in these environments may represent a potential increase of hazard. A first approach was addressed to in vitro evaluate survival, acid tolerance response, ability to produce biofilm, and capability to invade intestinal-like cells of a L. monocytogenes strain grown under experimental conditions mimicking environmental features that this pathogen encounters in soft cheeses (such as acid pH and high NaCl content). A second set of experiments was performed to monitor, during the storage at 4 degrees C, the survival of acid-adapted and nonadapted Listeriae in artificially contaminated soft cheeses. Both acid tolerance response and invasion efficiency of acid-adapted bacteria resulted in an increase, even when bacteria were simultaneously pre-exposed to increasing salt stress. The contamination of cheeses with acid-adapted and nonadapted bacteria evidenced in all products a good survival. A significant increased survival, the recovery of bacterial cells highly resistant to lethal pH exposure, and the prevalence of filamentous structures were observed in crescenza cheese during the storage. The Listeria survival and acid pH tolerance observed during refrigerated storage are probably related to the intrinsic acid and saline features of soft cheeses analysed. Italian soft cheeses tested may represent a potential hazard for the recovery of acid-adapted L. monocytogenes cells with enhanced ability to adhere to inert surfaces and/or to penetrate host cells.

Shelf Life of Crescenza Cheese as Measured by Electronic Nose

The shelf life of Crescenza, a traditional Italian soft cheese, was measured using classical analysis and a commercial electronic nose. Two lots of samples directly supplied by a manufacturer at the beginning of their commercial life were stored at 2 constant temperatures (8 and 15°C) and analyzed until their respective expiration dates. Among the physicochemical parameters, pH, acidity, hue, and apparent yield rheological index appeared to be the best predictors of the quality decay. Changes in these indices were described with a sigmoidal transition function allowing definition of a loose and a severe shelf-life protocol, based on the trend of first and second time derivatives. A time range of 1 to 3 d at 15°C and 4 to 8 d at 8°C was accordingly assessed to maintain the freshness of Crescenza cheese. The quality decay of cheese aroma was evaluated by inspecting the headspace fingerprint of the same set of samples using the electronic nose. Sample classification through the aroma fingerprint confirmed the predicted shelf-life time ranges. A clear discrimination between “fresh,” “aged,” and “very aged” samples was obtained using principal components analysis, cluster analysis, and linear discriminant analysis statistical techniques. The predictive ability of the linear discriminant analysis classification model was confirmed by considering a new set of cheese samples purchased at the beginning of their commercial life from a local market and analyzed until their expiration date.

Application of FT-NIR and FT-IR spectroscopy to study the shelf-life of Crescenza cheese

Crescenza is a fresh cheese in which “freshness” is associated with low acidity, limited proteolysis, and no bitter taste. In this study, FT-NIR and FT-IR spectroscopy was applied to evaluate the shelf-life period in which “freshness” is maintained. Cheese samples were analysed at different times for 20 days. Spectral data were collected using a FT-NIR spectrometer with an optic fibre (from 12000 to 4000 cm−1), and a FT-IR spectrometer with an ATR cell (from 4000 to 700 cm−1). Principal component analysis was able to detect the decrease of Crescenza “freshness” and to define the critical day during shelf-life. These results are in agreement both with those reported in previous studies and with those of physico-chemical and chemical tests. The principal absorption bands relating to the milk components involved were determined. The advantage of using IR spectroscopy is to rapidly draw a profile of the product related to its total quality.

Effects of milk treatment with dynamic high pressure on microbial populations, and lipolytic and proteolytic profiles of Crescenza cheese

The effects of some physical treatments of milk (pasteurization and homogenization at 1000 bar) on the evolution of the microbial populations, as well as on the proteolytic and lipolytic profiles, of Crescenza, a traditional Italian soft cheese, were studied in relation to its shelf‐life. The dynamic, high‐pressure homogenization (HPH) treatment of milk caused a reduction in the cell loads attained by the expiry date of yeasts and Pseudomonas spp. Moreover, the thermal and HPH treatments had different selective actions on the yeast populations, the former favouring oxidative species. In addition, the Crescenza obtained using milk treated at 1000 bar showed evidence of early and significant lipolysis.

Peptides from several italian cheeses inhibitory to proteolytic enzymes of lactic acid bacteria, pseudomonas fluorescens ATCC 948 and to the angiotensin I-converting enzyme

Water-soluble peptides from Mozzarella, Italico, Crescenza, and Gorgonzola cheeses were fractionated by reverse-phase fast protein liquid chromatography. Peptide fractions with inhibitory activity to amino- and endo-peptidases from Lactobacillus delbrueckii ssp. bulgaricus B397, Streptococcus thermophilus 305, and Lactococcus lactis ssp. cremoris Wg2 were found. Enzymes from Lactobacillus casei ssp. casei 2752 were less sensitive. Endopeptidase from Lactobacillus casei ssp. casei 2752 also had a different response to the effect of some inhibitors. It probably showed limited differences in catalysis and substrate positioning. Most of these inhibitory peptides were also effective in reducing the activity of the Pseudomonas fluorescens ATCC 948 endopeptidase and the angiotensin I-converting enzyme. Inhibitory peptide fractions from Mozzarella, Italico, and Crescenza cheeses had a certain degree of hydrophobicity while the peptide fraction from Gorgonzola cheese eluted in the initial part of the acetonitrile gradient. One of the inhibitory peptides contained in the water-soluble extract of Crescenza cheese was further purified and sequenced. It corresponded to the β-casein fragment 58-72.

Production of Crescenza Cheese by Incorporation of Bifidobacteria

Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium longum were incorporated into Crescenza cheese, individually or as multispecies mixtures and as free cells or as cells immobilized in calcium alginate gel. The viability of the bifidobacteria differed in 14-d-old cheeses: when added individually, the cell counts of B. bifidum, B. longum, and B. infantis were log10 8.05, 7.12, and 5.23 cfu/g, respectively. The multispecies mixtures only reached about log10 5.0 cfu/g of cheese. The presence of bifidobacteria did not influence the aerobic microflora, the growth of Streptococcus thermophilus used as starter, or the gross composition of the cheese. No differences were found in the primary proteolysis with respect to the conventional production of Crescenza cheese, but higher levels of pH 4.6-soluble N and more pronounced activities of aminopeptidase, iminopeptidase, dipeptidase, and tripeptidase were detected in all of the cheeses with added bifidobacteria. Crescenza cheeses with added bifidobacteria contained only traces of lactose and had slightly higher concentrations of lactic and acetic acids than did the conventional cheese. The presence of bifidobacteria was also related to high α- and β-galactosidase activities in the cheese. Sensory evaluation of the cheeses with incorporated bifidobacteria was very similar to that of Crescenza cheese produced by the conventional method.