Months Of Ripening Research Articles

Antihypertensive effect of peptides naturally generated during Iberian dry-cured ham processing

Iberian dry-cured ham is considered a product of excellence in Spain and also highly valued by consumers overseas. Its processing conditions include a minimum time of ripening of 24months which results on a very intense proteolysis of muscular proteins due to the action of endogenous enzymes and the generation of numerous peptides and free amino acids responsible for its characteristic flavour properties.Previous studies in Spanish dry-cured ham of 10months of ripening identified the amino acid sequences of many of the peptides generated during the proteolysis as well as described their potential as bioactive peptides. However, differences in genetics and processing conditions such as the time of ripening, could result on differences in the action of endogenous enzymes and the generated peptides.In this study, differences in the generated peptides between Iberian dry-cured (24months of ripening) and traditional Spanish dry-cured ham (14months of ripening) have been detected. Iberian dry-cured ham extract was separated using size-exclusion chromatography and the ACE-inhibitory activity of the obtained fractions was evaluated in vitro showing up to 97.7% of inhibition in some of the fractions. The antihypertensive effect of the Iberian ham extract was also assayed in vivo using spontaneously hypertensive rats. A significant decrease of 12mmHg in SBP after 8h of ingestion (p<0.05) that returned to values similar to the control after 24h of the treatment was observed. The analysis by mass spectrometry in tandem of the peptide extract revealed a total of 2632 peptides which contained the ACE inhibitory Pro–Pro–Lys, Pro–Ala–Pro, and Ala–Ala–Pro repeated in their sequences a total of 322, 302 and 119 times, respectively. This study reveals Iberian dry-cured ham as a source for natural antihypertensive peptides with very high potential in comparison with Spanish dry-cured ham, probably due to the differences in genetics and time of ripening which influence proteolysis and thus the generation of peptides.

Spatial Distribution of Lactococcus lactis Colonies Modulates the Production of Major Metabolites during the Ripening of a Model Cheese.

In cheese, lactic acid bacteria are immobilized at the coagulation step and grow as colonies. The spatial distribution of bacterial colonies is characterized by the size and number of colonies for a given bacterial population within cheese. Our objective was to demonstrate that different spatial distributions, which lead to differences in the exchange surface between the colonies and the cheese matrix, can influence the ripening process. The strategy was to generate cheeses with the same growth and acidification of a Lactococcus lactis strain with two different spatial distributions, big and small colonies, to monitor the production of the major ripening metabolites, including sugars, organic acids, peptides, free amino acids, and volatile metabolites, over 1 month of ripening. The monitored metabolites were qualitatively the same for both cheeses, but many of them were more abundant in the small-colony cheeses than in the big-colony cheeses over 1 month of ripening. Therefore, the results obtained showed that two different spatial distributions of L. lactis modulated the ripening time course by generating moderate but significant differences in the rates of production or consumption for many of the metabolites commonly monitored throughout ripening. The present work further explores the immobilization of bacteria as colonies within cheese and highlights the consequences of this immobilization on cheese ripening.

An MRI method for monitoring the ripening of Grana Padano cheese

In this paper, we propose a magnetic resonance imaging (MRI) method for assessing the ripening stage of Grana Padano, one of the most appreciated long-ripened hard cooked Italian cheeses. The method is based on a combination of MRI analysis with a study of multi-component transverse relaxation (T2) distributions. Three different ripening stages (12, 16 and 20 months) were considered and, for each stage, three samples were investigated (for a total of nine samples). The relaxation profiles of differently ripened Grana Padano cheeses varied in terms of area fraction relative to the three observed components of T2 relaxation. In particular, a good linear relationship was observed between the area fraction of the first T2 population (mainly constituted by water protons in chemical exchange with labile protein protons) and the months of ripening. The proposed method might have a general validity for different kinds of cheese.

Evaluation of Toma Piemontese PDO cheese as a carrier of putative probiotics from table olive fermentations

Two strains of Lactobacillus plantarum (Lp S11T3E and Lp S2T10D) and one of Lactobacillus pentosus (Lps S3T60C), originally isolated from table olive fermentations, and previously characterized for their probiotic properties, have been added as adjunct cultures to Toma Piemontese Protected Denomination of Origin (PDO) cheese, in order to develop a functional dairy product. The cheeses were sampled throughout their manufacturing process and during the two months of ripening. Moreover, they were also subjected to in vitro human digestion, followed by microbiological analysis. Monitoring of the inoculated strains was performed through molecular identification and biotyping. The organic acid and sugar contents of the cheeses were determined at each sampling point, while the organoleptic features were assessed by sensory evaluation. All isolated lactobacilli, during ripening and after digestion of the cheeses, were recognized as putative probiotics, and demonstrated to be well adapted to the food matrix investigated. The organic acid composition of the cheeses with the adjunct culture differed from the control, but this difference did not negatively affect the organoleptic profiles of the final product. Therefore, all the strains tested were to be usable as adjunct cultures in Toma Piemontese PDO production to develop a new functional food.

Microbiological and physicochemical properties of dry‐cured neck inoculated with probiotic of Bifidobacterium animalis ssp. lactis BB‐12

SummaryThe effect of inoculum level of Bifidobacterium animalis ssp. lactis BB‐12 probiotic strain and ripening period on the quality of dry‐cured neck was studied. The microbiological parameters (Enterobacteriaceae, LAB and TVC) and physicochemical attributes (pH value, aw, TBARS index, colour) were determined directly after fermentation at 15 °C for 3 weeks, after 6 and 12 months of ripening at 4 °C. The highest LAB count and a lower pH value were found in the meat inoculated with probiotic strain at 6.6 log cfu g−1 (B2) followed by inoculation with probiotic strain at 6.3 log cfu g−1 (B1). Level of inoculation had not had an influence on water activity, TBARS index and total colour parameters. Changes of fat oxidation during half‐year of ripening were limited in probiotic meat samples compared to naturally fermented control meat (C). Based on the results, it can be concluded that the most favourable physicochemical and microbiological parameters of the dry‐cured neck were obtained after 6 months of ripening. At that time, the Bifidobacterium BB‐12 at both levels is a good potential starter for meat fermentation.

Maiorchino Cheese: Physico-Chemical, Hygienic and Safety Characteristics.

This study assessed the physical, chemical, and microbiological characteristics of traditional Maiorchino cheese (Italy) made from raw ewe’s milk or from a mixture with goat’s milk. Cheese samples from the same batch were analyzed after 20 days and 6, 8, 12, 17 and 24 months of ripening. A decrease in moisture level lead to progressive total solids concentration (fat, total nitrogen, total solids and chloride) during ripening. Aw values decreased from 0.97 (day 20) to 0.85 (month 24), while pH increased from 4.99 to 5.41 (6 months) followed a by reduction until 4.85 (month 24). In samples analysed 20 days after cheesemaking, aerobic mesophilic count was 1.8•107 CFU/g, Enterobacteriaceae were 2.7•106 CFU/g, Staphylococcus spp. were 1.8•104 CFU/g, and yeasts 4.5•105 CFU/g. Sulphite reducing bacteria were not found. Lactic bacteria count at 30°C (LAB30) and 42°C (LAB42) was about 108 CFU/g (day 20); LAB30 reduced until month 8; LAB 42 reduced until month 12; both were not detectable at months 17 and 24. Cheese-making process does not consider commercial starter cultures and LAB group is heterogeneous because of its natural microflora. Yeasts were considered as typical microflora of Maiorchino. Volatile compounds were examined at 6, 12 and 24 months of ripening; 54 components were identified. Statistical analysis showed that the seasoning period of 12 months was the best for Maiorchino flavour attributes. The characterisation of Maiorchino traditional cheese may be considered as significant for this old traditional product, with the aim of obtaining the PDO certification.

Potential of Lactobacillus curvatus LFC1 to produce slits in Cheddar cheese

Defects in Cheddar cheese resulting from undesired gas production are a sporadic problem that results in significant financial losses in the cheese industry. In this study, we evaluate the potential of a facultatively heterofermentative lactobacilli, Lactobacillus curvatus LFC1, to produce slits, a gas related defect in Cheddar cheese. The addition of Lb. curvatus LFC1 to cheese milk at log 3 CFU/ml resulted in the development of small slits during the first month of ripening. Chemical analyses indicated that the LFC1 containing cheeses had less galactose and higher levels of lactate and acetate than the control cheeses. The composition the cheese microbiota was examined through a combination of two culture independent approaches, 16S rRNA marker gene sequencing and automated ribosomal intergenic spacer analysis; the results indicated that no known gas producers were present and that high levels of LFC1 was the only significant difference between the cheese microbiotas. A ripening cheese model system was utilized to examine the metabolism of LFC1 under conditions similar to those present in cheeses that exhibited the slit defect. The combined cheese and model system results indicate that when Lb. curvatus LFC1 was added to the cheese milk at log 3 CFU/ml it metabolized galactose to lactate, acetate, and CO2. For production of sufficient CO2 to result in the formation of slits there needs to be sufficient galactose and Lb. curvatus LFC1 present in the cheese matrix. To our knowledge, facultatively heterofermentative lactobacilli have not previously been demonstrated to result in gas-related cheese defects.

VLIV ZRÁNÍ NA TEXTURNÍ VLASTNOSTI EIDAMSKÝCH SÝRŮ

In this study were evaluated the Edam cheeses with fat content in dry matter 30% and 45% (w/w) produced using two different starter cultures YY and LL during 6 months of ripening. Sampling times were 26, 54, 89, 117, 146 and 180 days after production. The surface and central parts of cheeses have been evaluated separately.Cheese texture was analysed by using a Tira test 27025. The force needed to compress the sample was recorded (N). Ripening time had significant effect on rheological characteristics of the cheeses. The improvement of texture was related to the ripening time. At the beginning of ripening (1st month), there is a significantly higher hardness on surface layer of the cheese in samples of cheeses with 30% fat in dry matter. This is the case in both cultures. This difference has evened out after 2 months of ripening. The force needed to compression of the centrepiece of cheese with lower fat content in dry matter was 30.96 N and of cheese with higher fat content in dry matter 36.51 N, while after 60 days of ripening of cheese with lower fat content in dry matter it was 50.56 N and of cheese with higher fat content in dry matter 63.23 N.The influence of two different types of starter culture on the texture was evaluated. It was found out that after 60 days of ripening of cheese with 45% (w/w) fat in dry matter there was significant difference (P ≤ 0.01) in the firmness between cheese with starter culture YY (force 63.23 N) and LL (force 48 N). In every Edam sample after 3 months of aging (optimal ripe Edam) there was no dependence on the type of starter culture. After 120 days of ripening there was a significant difference in firmness of cheese with culture YY (44.58 N) and LL (33.61 N). Satistically significant difference (P ≤ 0.05) between the firmness of the surface and the central parts of the cheese was not found after one month of ripening.

Studium enterokoků a jejich role v produkci tyraminu během výroby a zrání polotvrdých sýrů

The aim of this study was isolation, identification and characterization of bacteria of the genusEnterococcusfrom Duch-type semi-hard cheese during manufacture and ripening. Cheese samples from two different producers (I and II) were used at the production day and after 30, 90 and 176 days of ripening.Altogether 361 suspected enterococci isolates were obtained from cheese samples during 7 month of ripening. Using genus-specific PCR, 285 isolates were identified as the members of the genusEnterococcus. The identification of fiveEnterococcusspecies was performed by PCR using species-specific primers. Among 165Enterococcusspp. isolates of producer I, 81 isolates were classified asE. faecium, 39 asE. durans, 21 asE. faecalis, 19 asE. casseliflavusand 3 asE. hirae, and 2 isolates were not classified into species. Enterococci species among isolates of producer II were as follows: 52 isolates ofE. faecium, 38 ofE. faecalis, 14 ofE. durans, 12 ofE. casseliflavus, 3 ofE. hiraeand 1 was not classified into species.E. faeciumwas found to be the dominating species in all cheese samples. The gene coding for tyrosine decarboxylase was detected in 10 enterococci isolates of producer I and in 5 enterococci isolates of producer II. Production of biogenic amine tyramine was confirmed in all these isolates, which were ofE. faecium,E. faecalisandE. duransspecies. It was confirmed that these species are important for tyramine production. There is the relationship between tyramine production and counts ofE. faecium,E. faecalisandE. durans. No tyramine production was observed in isolates ofE. casseliflavusorE. hiraespecies.

Minerals and Lactic Acid Contents in Buffalo Milk Cheddar Cheese; a Comparison with Cow

The aim of the study was to compare the minerals and lactic acid profile of Cheddar cheese prepared from cow and buffalo milk. Milks standardized at 4% fat level were used to prepare Cheddar cheese. The cheese was prepared and stored for 120 days ripening at 4°C. Chemical composition and minerals contents were determined at one month intervals during ripening. Lactic acid concentration was estimated after 2 and 4 months of ripening. The results revealed that cheese from buffalo milk had significantly higher level of fat, protein, ash, lactose and lactic acid contents as compared to that prepared from cow milk. Sodium, calcium and potassium contents were also considerably higher in the cheese prepared from buffalo milk. During ripening, significant decrease in lactose and pH value, while increase in acidity and lactic acid contents was observed. However, ripening did not influence the minerals profile of the cheese. It was accomplished that buffalo milk Cheddar cheese is nutritionally superior to cow milk cheese.

CHEMICAL CHARACTERISTIES OF ITALIAN RICOTTA CHEESE AS INFLUENCED BY THE PROTEOLYSIS DURING RIPENING.

The objective of the present work is to study the role of proteolysis being occurred in the Italian Ricotta Forte cheese throughout 20 months of ripening. Samples were taken for the examination after 1(day),and the after 1,2,4,6.12 and 19 months. Samples were analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which showed that the level of bovine serum albumin decreased towards the end of the ripening. However,α-lactalbumin and β-lactoglobulin did not degrade rapidly during the ripening. Meanwhile,the levels of pH 4.6-soluble N (SN) as a % of total N (TN) and total free amino acids (FAA) increased towards the end of the ripening. This study improves our understanding about the compositional and proteolytic parameters of Ricotta Forte cheese.

Absence of growth ofListeria monocytogenesin naturally contaminated Cheddar cheese

Each cheese producer is responsible by the legislation for the number of Listeria monocytogenes in cheese and is required to prove that numbers will not exceed 100cfu/g throughout the shelf-life of the cheese. Even in the case of hard-cheese such as Cheddar cheese, the absence of growth of List. monocytogenes during ripening has to be demonstrated to comply with EU legislation. Studies dedicated to assessing List. monocytogenes growth throughout cheese shelf-life are generally based on artificially contaminated cheeses. Contrary to the majority of works, the current study focused on the growth of List. monocytogenes in naturally contaminated raw milk farmhouse Cheddar cheeses during a five-month ripening period. List. monocytogenes growth was assessed by direct count and its presence was detected by enrichment in two naturally contaminated cheese batches. In order to track routes of contamination, 199 processing environment samples from inside and outside the processing facility were taken, and their analysis for the presence of List. monocytogenes was performed on four occasions over a 9-month period. List. monocytogenes isolates were differentiated using PFGE and serotyping. List. monocytogenes never exceeded 20cfu/g in the cheeses and could not be detected after five months of ripening. Eleven pulsotypes were identified. One pulsotype was found in the yard outside the processing facility, in a vat, on the processing area floor and in a cheese. This indicated that the outside environment constitutes a potential source of contamination of the processing environment and of the cheese. These results demonstrate that this farmhouse Cheddar cheese does not support List. monocytogenes growth and suggests that the efforts to reduce processing environment contamination are worthwhile.

The influence of alkaline earth metal equilibria on the rheological, melting and textural properties of Cheddar cheese

The total calcium content of cheese, along with changes in the equilibrium between soluble and casein (CN)-bound calcium during ripening can have a major impact on its rheological, functional and textural properties; however, little is known about the effect of other alkaline earth metals. NaCl was partially substituted with MgCl2 or SrCl2 (8·7 and 11·4g/kg curd, respectively) at the salting stage of cheesemaking to study their effects on cheese. Three cheeses were produced: Mg supplemented (+Mg), Sr supplemented (+Sr) and a control Cheddar cheese. Ca, Mg and Sr contents of cheese and expressible serum obtained therefrom were determined by atomic absorption spectroscopy. Addition of Mg2+ or Sr2+ had no effect on % moisture, protein, fat and extent of proteolysis. A proportion of the added Mg2+ and Sr2+ became CN-bound. The level of CN-bound Mg was higher in the +Mg cheese than the control throughout ripening. The level of CN-bound Ca and Mg decreased during ripening in all cheeses, as did % CN-bound Sr in the +Sr cheese. The presence of Sr2+ increased % CN-bound Ca and Mg at a number of ripening times. Adding Mg2+ had no effect on % CN-bound Ca. The +Sr cheese exhibited a higher G' at 70°C and a lower LTmax than the control and +Mg cheeses throughout ripening. The +Sr cheese had significantly lower meltability compared with the control and +Mg cheeses after 2 months of ripening. Hardness values of the +Sr cheese were higher at week 2 than the +Mg and control cheeses. Addition of Mg2+ did not influence the physical properties of cheese. Supplementing cheese with Sr appeared to have effects analogous to those previously reported for increasing Ca content. Sr2+ may form and/or modify nanocluster crosslinks causing an increase in the strength of the para-casein matrix.

Qualitative, chemical and nutritional traits of dry-cured ham of Sarda breed pigs: effect of rearing system

The aim of the study was to evaluate the effect of different rearing systems on some traits of Sarda breed pig ham. Twelve pigs were randomly assigned to the following three feeding systems: A, outdoor rearing system and fed ad libitum with a commercial concentrate; B, outdoor rearing and fed with ground barley (1.8 kg/head/day); C, fed at pasture in the woods and receiving 500 g/head/day of barley grain. After slaughter (22 months of age) the left thighs were processed for the production of the “pressuttu” (Sarda hams). After 14 months of ripening, ham weight loss was recorded and composition and chemical properties were determined in muscle and fat tissue. Rearing systems affected tissue and chemical composition of Sarda ham. Fresh ham weight and fat percentage were the highest in group A which showed the lowest value of seasoning weight loss (18.94 ± 1.51 vs. 28.44 ± 1.66 vs. 24.76 ± 1.32 for A, B and C group respectively). Dry-cured ham from pigs reared in outdoor system B showed higher content (P &lt; 0.001) of total protein and soluble nitrogen (SN/TN) than those from the other groups. Hams from groups A and B were characterized by the highest content of the saturated fatty acids (SFA). Fatty acids profile of dry-cured ham from group C showed the highest value of oleic and linolenic acids, and consequently the highest monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids content and more favorable values of PUFA/SFA and ω6/ω3 ratio. Pasture feeding is more suitable to obtain products with high nutritional properties.

Physico‐chemical, biochemical and microbiological changes of Kumpia wieprzowa during ripening

PurposeThe purpose of this paper is to estimate physico‐chemical, biochemical and microbiological changes during the three‐month ripening of the Polish traditional raw smoked fermented meat product Kumpia wieprzowa, produced from pork shoulder without fore‐shank.Design/methodology/approachAfter one, two and three months, the pH, aw, chemical composition, the content of nitrogen – total and soluble – as well as the profile of aromatic compounds and microflora, were evaluated.FindingsDuring ripening, the water content decreased from 62.7 percent to 47.5 percent, while the protein and fat amount increased from 20.8 percent to 25.0 percent and from 9.7 percent to 16.3 percent, respectively; the aw decreased from 0.95 to 0.88 and pH from 5.80 to 5.35. The proteolytic changes, measured by free amine groups and Nsoluble content, as well as the quantity of free fatty acids and percentage of most of the volatile compounds increased, particularly during the first two months of ripening. The total number of aerobic microorganisms, and Lactobacillaceae decreased during ripening from 7.9 to 6.2 and 5.6 to 4.7 log cfu/g, respectively. The count of coagulase‐negative cocci changed from 5.3 to 5.2 log cfu/g.Originality/valueKumpia wieprzowa is a unique pork product, entered on the List of Polish Traditional Products in 2005. Up to the present, the properties of Kumpia wieprzowa were not recognized and published in the scientific literature, in spite of its very interesting raw material (shoulder spontaneously fermented as a whole large primal cut).

Diversity and dynamic of lactic acid bacteria strains during aging of a long ripened hard cheese produced from raw milk and undefined natural starter

The aim of this study was to explore diversity and dynamic of indigenous LAB strains associated with a long ripened hard cheese produced from raw milk and undefined natural starter such as PDO Grana Padano cheese. Samples of milk, curd, natural whey culture and cheeses (2nd, 6th, 9th and 13th months of ripening) were collected from 6 cheese factories in northern Italy. DNA was extracted from each sample and from 194 LAB isolates. tRNAAla-23S rDNA-RFLP was applied to identify isolates. Strain diversity was assessed by (GTG)5 rep-PCR and RAPD(P1)-PCR. Finally, culture-independent LH-PCR (V1–V2 16S-rDNA), was considered to explore structure and dynamic of the microbiota. Grana Padano LAB were represented mainly by Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus delbrueckii, Lactobacillus helveticus and Pediococcus acidilactici, while the structure and dynamic of microbiota at different localities was specific. The strength of this work is to have focused the study on isolates coming from more than one cheese factories rather than a high number of isolates from one unique production. We provided a valuable insight into inter and intraspecies diversity of typical LAB strains during ripening of traditional PDO Grana Padano, contributing to the understanding of specific microbial ecosystem of this cheese.

FT-NIR and FT-MIR spectroscopy to discriminate competitors, non compliance and compliance grated Parmigiano Reggiano cheese

In this investigation the potential of infrared spectroscopy, coupled to different statistical methods, were used to estimate the authenticity of grated Protected Denomination of Origin (PDO) Parmigiano Reggiano cheese (P-R).The feasibility of the analytical approach in the prediction of cheese authenticity without the use of wet chemistry was evaluated. A total of 400 plastic-sealed grated cheese samples classified as: compliance P-R, competitors, non-compliance P-R (defected P-R), and P-R with rind content of >18%. PCA was conducted for an explorative spectra analysis. Soft independent modelling of class analogy (SIMCA) analysis and artificial neural networks (ANNs) were used to classify samples, according to different cheese categories. For both the spectroscopic techniques, PCA correctly discriminated compliance P-R from competitors, but not the P-R as a function of the rind percentage and months of ripening. SIMCA analysis accurately classified the compliance and competitors' P-R samples, while samples belonging to the classes of defected P-R and P-R with rind content >18% were not accurately classified. ANN was more efficient than SIMCA in the classification of all the cheese classes. The results showed that NIR and MIR combined with different statistical approaches can be suitable for a sensitive, non-destructive, rapid and inexpensive screening of grated P-R cheese authenticity.

ACE-Inhibitory Activity of Cheddar Cheeses Made with Adjunct Cultures at Different Stages of Ripening

In this study, cheddar cheeses made with adjunct cultures L. casei ssp. casei 300 (CCA) and L. paracasei ssp paracasei 22 (CCB) were assessed for ACE inhibitory activity at different stages of ripening. ACE-inhibitory activity of the UF permeates of WSE of all the cheeses increased significantly (P<0.05), especially after the first two months of ripening. The inhibitory activity continued to increase in the cheeses made with adjunct cultures CCA (IC50 value 0.16 mg.ml-1) and CCB (IC50 value 0.20 mg.ml-1) up to third month and in CCC increased to this level after fourth month of ripening (IC50 value 0.20 mg.ml-1). The electrophoretic and RP-HPLC profiles indicated that the rate of degradation of proteins resulted in formation of smaller peptides which were higher in cheese made with adjunct cultures as compared to control cheese The result also indicated that cheeses with the addition of adjunct had higher ACE-inhibitory activity than control cheese.

Total fatty acids composition of raw and ripe Slavonian kulen in relation to raw material used

The experiment was performed to study the changes in composition of total fatty acids during the ripening of Slavonian kulen (SK), dry-fermented sausages produced from raw material (pork meat and back fat) obtained from the feeding experiment in which toasted (T) or thermally non-treated (NT) corn-grain were used in pig’s diets. All sausages were prepared using the same production technology and under the similar conditions of fermentation/ripening. Chemical analyses (content of moisture, crude protein, crude fat, ash and total fatty acid composition) were performed on the samples (n = 6) of T and NT batches taken before stuffing (raw pork/fat mixture) and on the dry-sausages (n = 6) of both groups after six months of ripening. The results indicate that T corn-fed pork/fat raw mixture did not differ in chemical composition, but had less monounsaturated (i.e., less C18:1) and more polyunsaturated (i.e., more C18:2n-6 and C18:3n-3) fatty acid composition as compared to NT raw mixture. As expected, the chemical composition throughout drying/ripening underwent a significant change; the content of moisture decreased, while the contents of protein, fat and ash increased to similar final values in both groups. On the other hand, ripening had little effect on the initial fatty acid composition; only C22:5n-3 proportion decreased with time in both groups. In conclusion, total fatty acid profile of ripe SK in this study largely reflects the fatty acid composition of raw materials used, without major changes during the six-month ripening.

Effect of gum tragacanth on the rheological and functional properties of full-fat and half-fat Cheddar cheese

Fat replacers can be used to improve the sensory and functional properties of reduced-fat cheeses. The effect of gum tragacanth (GT) on the rheological, functional and sensory properties of half-fat and full-fat Cheddar cheese during ripening was investigated. Four Cheddar-style cheeses were made in triplicate: full-fat control (FFC), half-fat control (HFC), full fat + GT (FFGum) and half fat + GT (HFGum). Cheesemilk for the latter two cheeses was supplemented with GT at a level of 0.05% (w/v); all cheeses were ripened at 8 °C for 10 months. Moisture and moisture-to-protein ratio were increased by GT addition. GT addition resulted in decreased pH in both FFGum and HFGum cheeses during ripening, especially the FFGum cheese. GT appeared to affect proteolysis only in the FF cheeses. GT was successful in decreasing hardness and springiness values during ripening. GT increased meltability in the FFGum cheese and to a lesser extent in the HFGum cheese in late ripening. An increase in opaqueness was also observed due to GT addition regardless of fat level. Dynamic small amplitude oscillatory rheology showed a depression in LTmax and an increase in G′ at 75 °C caused by GT at 7 months of ripening. GT did not appear to have any impact on starter bacteria and NSLAB counts. Results from a consumer ranking preference test showed that the GT was not successful in fully mimicking the sensory properties of the FFC cheese. These results suggest that GT appears more suited to enhancing the textural and functional properties of half-fat Cheddar cheese than its sensory properties.