Cheddar Cheese Research Articles

Quality of Analysis Chicken Nugget with the Addition of Cheddar Cheese

This study aims to analyze the quality of discarded layer chicken nuggets produced from the addition of cheddar cheese as much as 10%, 20%, 30% and 40% which includes shape, color, aroma, texture and taste. This type of research is a pure experiment using the Completely Randomized Design (CRD) method which has been carried out 5 treatments and 3 repetitions. The object of this research is rejected layer chicken nuggets with the addition of cheddar cheese as much as 10%, 20%, 30% and 40% of the quality of the nuggets. The types and sources of data used are primary data obtained directly from 3 expert panelists by filling out the organoleptic test format on the quality of rejected laying hens. Data analysis used ANOVA analysis (ANAVA). If the analysis of variance shows Fcount > Ftable, Duncan's test will be performed. The results showed that the addition of cheddar cheese had a significant effect on the quality of the neat shape (rectangular 6 cm x 1.5 cm x 1.5 cm), uniform shape, texture (chewy) of discarded layer chicken nuggets and on the quality of color, aroma and taste. taste has no significant effect. The results of the quality test of laying hens nuggets with cheddar cheese were the best in treatment X1 with the addition of 10% cheddar cheese.

Lactiplantibacillus plantarum as an adjunct culture exhibits antifungal activity in shredded Cheddar cheese

Fungal spoilage is a substantial concern for the dairy industry, due to mycotoxin formation and a cause of food waste. In this study, several strains of Lactiplantibacillus plantarum from different sources were investigated for their antifungal activity and performance as adjunct cultures in Cheddar cheese production. All strains grew well in milk with minimal acidification. Although high concentrations of NaCl affected their growth in agar-based media, the salt concentration did not influence their antifungal activity towards the major spoilage mould Penicillium commune. L. plantarum strains were able to be inoculated in milk simultaneously as cheese starter cultures, without obstructing acid production. When added at the start of Cheddar cheese production as adjunct cultures, all strains of L. plantarum significantly prolonged the shelf life of shredded cheese. Visual spoilage of shredded cheese with deliberately inoculated P. commune was delayed a further 2–3 days when L. plantarum was included as an adjunct culture, compared to cheese without L. plantarum addition. Environmental fungal spoilage of shredded cheese was delayed by more than 20 days when L. plantarum was included as an adjunct culture in Cheddar cheese production, compared to cheese without L. plantarum addition. The results of this study show that L. plantarum has potential as a biopreservative adjunct culture in Cheddar cheese.

Characterization of the key nonvolatile metabolites in Cheddar cheese by partial least squares regression (PLSR), reconstitution, and omission

Cheddar cheese was desirable by consumers worldwide due to its characteristic taste and aroma, but limited information was available about taste contributors. Therefore, sensory profiles of natural Cheddar cheeses were investigated by quantitative descriptive analysis (QDA). Umami, salty, and brothy attributes were the principal differential attributes. Nonvolatile metabolites were analyzed to decipher their taste contributions, of which free amino acids (FAAs) and organic acids recorded the most considerable differences. The key taste compounds were identified by partial least squares regression (PLSR), reconstitution, and omission tests. NaCl and glutamic acid (Glu) were the primary contributors of salty and umami tastes, respectively. Sourness was synergistically affected by organic acids and Glu. Despite their limited taste impacts, the remaining amino acids intensified sourness and saltiness when mixed with Glu. Organic acids (especially in combination) and NaCl exhibited significant taste enhancements. These results provided deep insight into crucial nonvolatile metabolites promoting Cheddar cheese tastes.

Dynamics of Starter and Non-Starter Lactic Acid Bacteria Populations in Long-Ripened Cheddar Cheese Using Propidium Monoazide (PMA) Treatment.

The microbial community of industrially produced Canadian Cheddar cheese was examined from curd to ripened cheese at 30–32 months using a combination of viable plate counts of SLAB (GM17) and NSLAB (MRSv), qPCR and 16S rRNA gene amplicon sequencing. Cell treatment with propidium monoazide excluded DNA of permeable cells from amplification. The proportion of permeable cells of both Lactococcus spp. and Lacticaseibacillus spp. was highest at 3–6 months. While most remaining Lacticaseibacillus spp. cells were intact during later ripening stages, a consistent population of permeable Lactococcus spp. cells was maintained over the 32-month period. While Lactococcus sequence variants were significant biomarkers for viable cheese curd communities at 0–1 m, Lacticaseibacillus was identified as a distinctive biomarker for cheeses from 7 to 20 months. From 24 to 32 months, Lacticaseibacillus was replaced in significance by four genera (Pediococcus and Latilactobacillus at 24 m and at 30–32 m, Secundilactobacillus and Paucilactobacillus). These results underscore the importance of monitoring potential defects in cheeses aged over 24 months, which could be diagnosed early through microbial DNA profiling to minimize potential waste of product. Future perspectives include correlating volatile flavor compounds with microbial community composition as well as the investigation of intra-species diversity.

Determination of Biogenic Amines in Some Cheese Consumed in Hatay Region

Biogenic amines are biologically active, nitrogen based, low molecular mass substances and they consider as quality and toxicity indicators of foods. The amount of biogenic amines indicates also the freshness of the food products. These compounds form during production or storage of protein rich foods under unhygienic conditions. These amines are usually formed in protein rich foods by the act of microorganisms which has decarboxylase activity under inappropriate technological processing conditions especially while fermentation processes. Cheese, yogurt, kefir are among the most consumed fermented foods. Since these products are much consumed food products, the analysis of biogenic amines in them is very important in terms of consumer health and product quality. Biogenic amines taken in high amounts are known to cause headache, nausea and more serious food poisoning. There are studies both abroad and in our country on cheese varieties where biogenic amine formation is frequently observed. However, there is no study conducted in the Hatay region, which is extremely rich in terms of cheese varieties. Within the scope of this study, biogenic amine analyzes were performed on 20 cheese samples produced and consumed in the Hatay region after they were kept in the refrigerator at 4 ºC for 30 days. Total biogenic amine concentrations were determined between 57.00–432.41 mg kg-1. The samples with the highest total biogenic amine concentrations were blue-veined cheese (432.41 mg kg-1) and moldy cheese (314.45 mg kg-1). Total biogenic amine concentrations were the lowest in aged cheddar cheese (57.00 mg kg-1) and knitted cheese (97.57 mg kg-1). All of the biogenic amines (spermidine, putrescine, cadaverine, histamine, tryptamine, tyramine, phenylethyl amine) were detected in all cheese samples examined.

Vitamin K content of cheese, yoghurt and meat products in Australia

Vitamin K is vital for normal blood coagulation, and may influence bone, neurological and vascular health. Data on the vitamin K content of Australian foods are limited, preventing estimation of vitamin K intakes in the Australian population. We measured phylloquinone (PK) and menaquinone (MK) -4 to -10 in cheese, yoghurt and meat products (48 composite samples from 288 primary samples) by liquid chromatography with electrospray ionisation-tandem mass spectrometry. At least one K vitamer was found in every sample. The greatest mean (± standard deviation for foods sampled in multiple cities) concentrations of PK (4.9 µg/100 g), MK-4 (58 ± 9 µg/100 g) and MK-9 (8 ± 2 µg/100 g) were found in lamb liver, chicken leg meat and Cheddar cheese, respectively. Cheddar cheese (1.1 ± 0.3 µg/100 g) and cream cheese (1.0 µg/100 g) contained MK-5. MK-8 was found in Cheddar cheese only (4 ± 2 µg/100 g). As the K vitamer profile and concentrations appear to vary considerably by geographical location, Australia needs a vitamin K food composition dataset that is representative of foods consumed in Australia.

Cheese Intake Exhibits an Alteration of Glycolipid Profile and Impacts on Non-Alcoholic Fatty Liver in Bahraini Older Adults.

Background: Metabolic syndrome (MetS) is a multifactorial condition characterized by a complex interrelation between genetic and environmental factors that heighten the risk of cardiovascular diseases and all-cause mortality. It is hypothesized that diet may play an important role in the regulation of metabolic syndrome factors and influence the process. Therefore, the main objective of this study was to investigate the specific dietary patterns associated with metabolic syndrome markers and quantify the possible effects of dietary patterns among Bahrain older adults. Methods: This is a cross-sectional study that included 151 Bahraini patients diagnosed with MetS, 89 (58.7%) were females and 62 (41.3%) males. Results: The prevalence of Non-Alcoholic Fatty Liver was 89%. Statistically significant correlations were found between dairy products with low fat and SBP (r = 0.182, p < 0.001) body mass index (BMI) (r = −0.195; p < −0.01). Higher chicken consumption was associated with reduction of BMI (r = −0.273; p < −0.01). A higher consumption of ricotta and cheddar cheese (high in fat) was associated with higher levels of triglycerides (p < 0.01). Higher frequent consumption of rice (basmati) was associated with lower glucose levels (r = −0.200; p < −0.01). Fatty liver has been associated with high consumption of cream cheese (p < 0.01). Conclusion: In older Bahraini adults with metabolic syndrome, higher frequency of food consumption of full-fat cheese was linked with a derangement of lipid profile and Non-Alcoholic Fatty Liver. Positive effects on BMI have been recorded with higher-frequency consumption of basmati rice and chicken.

Effect of Saccharomyces cerevisiae ‐inoculated milk on the quality of cheese‐like products during storage

The development of new cheese with novel flavors is an increasing trend in the cheese market. Three experimental cheese-like products (ECs) with different processing parameters were manufactured from Saccharomyces cerevisiae-fermented milk, and their composition, functionality, volatile compounds, and sensory characteristics were compared with those of model Cheddar cheese (CC) during storage. Compared with CC, ECs had higher moisture content, yield, and pH but lower protein and fat content. In the early stage of storage, CC had the highest hardness and storage modulus, however, these values were higher in ECs than in CC with storing. After 90 days of storage, S. cerevisiae-inoculated milk significantly increased the levels of alcohols and esters in the ECs, contributing to high taste scores, especially ECs manufactured with high saccharose. Overall, cheese-like products manufactured from S. cerevisiae-fermented milk had a high yield, good functionality, and improved flavor profile and taste, with market potential. Novelty impact statement The development of new cheese with novel flavors is an increasing trend. Cheese-like products were manufactured from Saccharomyces cerevisiae-fermented milk. The resulted product had improved flavor profile and taste, with market potential.

Raman confocal microscopy to assess changes in cheddar cheese during maturation

Raman confocal microscopy is an increasingly useful technique when applied to food samples. It has the unique ability to interrogate the chemical structure, aligned with the same confocality capability that is available when using standard confocal microscopy. In this research, we used Raman confocal microscopy to investigate the effects of maturation on the microstructure of cheddar cheese. Statistical analysis of the spectral data showed significant protein structural changes as the cheese matured. The results illustrate the potential of Raman confocal microscopy in conjunction with spectroscopy and imaging to understand chemical changes in complex dairy matrices.

The Antithrombotic Potential of Bioactive Peptides Induced by Buffalo Milk Probiotic Cheddar Cheese

Cheddar cheese undergoes significant changes resulting in numerous microbiological and biochemical processes called glycolysis, lipolysis, and proteolysis, accountable for a unique texture, aroma, appearance, and taste. Specific bioactive peptides developed during these biochemical reactions impart health benefits. Addition of probiotics boots the development of bioactive peptides in foods. Objective: The current research investigated the therapeutic potential of water-soluble peptides (WSPs) extracts from buffalo milk probiotic Cheddar cheese regarding anti-thrombic facets. Methods: The appropriateness of Buffalo milk for Cheddar manufacturing was assessed by analysing its pH, acidity, fat, protein, and total solids content. Two batches of Cheddar cheese were produced, one having a mixture of Probiotic microorganisms and commercially available mesophilic cheese starter and the second containing only commercially available cheese starters. Both of the cheese batches were analysed for their physicochemical properties. Water-soluble extract of Cheddar cheese samples was analysed for anti-thrombic effects after two-month intervals during ripening. Results: Three concentrations of WSE of buffalo milk cheddar cheese were used to assess the antithrombotic effect during 60, 120, and 180 days of ripening at 4°C. Antithrombotic activity increased with the ripening period for both control and probiotic cheddar cheese samples Conclusion: A significantly increased effect of antithrombotic activity was observed by Probiotic adjunct on control cheddar cheese.

Impact of front-of-pack labels with nutrition and Grass-Fed claims on consumer perceptions and expected sensory and nutritional characteristics of Cheddar cheese – A comparative study of Irish and US consumers

Consumer interest in Grass-Fed dairy products is increasing with some consumer groups willing to pay a premium for dairy labelled as Grass-Fed. The aim of this study was to examine the effect of the term Grass-Fed on a label in combination with claims on fat content, on consumer perceptions of Cheddar cheese in Irish and US participants. Consumers from Ireland (n = 345) and the United States (n = 432) completed an anonymous online survey and were presented with one of two sets of cheese label images, either Regular-Fat and Regular-Fat-Grass-Fed or Lighter-Fat and Lighter-Fat-Grass-Fed. Participants were asked to rate expected sensory characteristics and perceived healthiness and naturalness, based on each label. Participants then selected a portion of each cheese that they would be likely to consume on a slice of toast for lunch, from 100 portion size images ranging from 1.2 g to 120 g. Inclusion of a Grass-Fed claim on a cheese label did not influence sensory expectations of cheese, but perceived healthiness and naturalness were higher, in both cohorts. The Lighter-Fat claim had a negative influence on sensory expectations, with consumers in both cohorts reporting a lower expected liking and flavour intensity. In the Irish cohort, a Lighter-Fat claim enhanced perceived healthiness. The front-of-pack claim had no impact on portion selection in US consumers. Irish consumers, however, chose a larger portion for the Lighter-Fat cheese compared to the Regular-Fat-Grass-Fed cheese. Inclusion of Grass-Fed on the label alongside information on Regular-Fat or Lighter-Fat may enhance consumers’ perceptions of healthiness and naturalness, without compromising sensory expectations. Products with Lighter labels may be chosen in larger portions, with potential implications for consumers who choose them as part of a weight-control strategy.

Identification of aroma-active compounds in Cheddar cheese imparted by wood smoke

Cheddar cheese is the most popular cheese in the United States, and the demand for specialty categories of cheese, such as smoked cheese, are rising. The objective of this study was to characterize the flavor differences among Cheddar cheeses smoked with hickory, cherry, or apple woods, and to identify important aroma-active compounds contributing to these differences. First, the aroma-active compound profiles of hickory, cherry, and apple wood smokes were analyzed by solid-phase microextraction (SPME) gas chromatography-olfactometry (GCO) and gas chromatography-mass spectrometry (GC-MS). Subsequently, commercial Cheddar cheeses smoked with hickory, cherry, or apple woods, as well as an unsmoked control, were evaluated by a trained sensory panel and by SPME GCO and GC-MS to identify aroma-active compounds. Selected compounds were quantified with external standard curves. Seventy-eight aroma-active compounds were identified in wood smokes. Compounds included phenolics, carbonyls, and furans. The trained panel identified distinct sensory attributes and intensities among the 3 cheeses exposed to different wood smokes (P < 0.05). Hickory smoked cheeses had the highest intensities of flavors associated with characteristic "smokiness" including smoke aroma, overall smoke flavor intensity, and meaty, smoky flavor. Cherry wood smoked cheeses were distinguished by the presence of a fruity flavor. Apple wood smoked cheeses were characterized by the presence of a waxy, green flavor. Ninety-nine aroma-active compounds were identified in smoked cheeses. Phenol, guaiacol, 4-methylguaiacol, and syringol were identified as the most important compounds contributing to characteristic "smokiness." Benzyl alcohol contributed to the fruity flavor in cherry wood smoked cheeses, and 2-methyl-2-butenal and 2-ethylfuran were responsible for the waxy, green flavor identified in apple wood smoked cheeses. These smoke flavor compounds, in addition to diacetyl and acetoin, were deemed important to the flavor of cheeses in this study. Results from this study identified volatile aroma-active compounds contributing to differences in sensory perception among Cheddar cheeses smoked with different wood sources.

Effect of ripening and in vitro digestion on free amino acids and Angiotensin I converting enzyme inhibitory (ACE-I) potential of cow and Buffalo milk cheddar cheeses

ABSTRACT Cheddar cheese is a source of a variety of biologically active peptides and free amino acids (FAAs), which contribute to the cheese aroma, flavors, and textures. The FAA liberation and angiotensin-converting enzyme inhibition potential of cheddar cheese made from cow and buffalo milk before and after in vitro digestion by gastric and duodenal enzymes with ripening were investigated. The cheese samples were stored under refrigeration condition (4°C) for ripening for 3, 6, and 9 months. The possible differences existing in the level of FAAs were explored before and after in vitro digestion of ripened cheddar cheese made from cow and buffalo milk. The lower level of angiotensin-converting enzyme inhibition value 62.4 ± 1.04% was observed in gastric digested cheese samples after 9 months of ripening, while the highest angiotensin-converting enzyme inhibition value 93.1 ± 1.29% was observed in duodenal digested cheese samples after 6 months of ripening. This study showed that before and after in vitro digestion, highest angiotensin-converting enzyme inhibitory potential of cheddar cheese was observed between 6 and 9 months of ripening. In 9-month ripened cheese, a significant increase in the contents of glutamic, glutamine, valine, leucine, and lysine was observed after duodenal digestion in case of both cow and buffalo milk Cheddar cheeses. The contents of valine, ornithine, and tryptophan were negligible before digestion and significantly increased afterward.

Protection of candidate probiotic lactobacilli by Cheddar cheese matrix during simulated gastrointestinal digestion

• Lacticaseibacillus rhamnosus and Lc. paracasei strains with probiotic characteristics isolated from cheese were used as adjuncts in cheese manufacture. • They do not significantly affect cheese composition or ripening characteristics. • They survived in cheese during ripening. • They survive simulated gastrointestinal digestion and the cheese matrix provides greater protection than fermented milk. Previously, Lacticaseibacillus rhamnosus DPC7102 and Lacticaseibacillus paracasei DPC7150 isolated from commercial Irish Cheddar cheeses were shown to exhibit probiotic traits in vitro . The objective of this study was to investigate how these strains survive in cheese and to explore whether a cheese or fermented milk matrix provided protection during simulated digestion using the INFOGEST 2.0 static digestion model. Manufacture of Cheddar cheese and fermented milks using these strains did not significantly impact cheese composition or ripening parameters. The Cheddar cheese matrix provided significantly more protection to non-starter lactic acid bacteria than the fermented milk. Pulsed-field gel patterns of isolates surviving simulated digestion confirmed the presence of the strains of interest. These data indicate that these two Lacticaseibacillus strains successfully persist in the cheese matrix during cheese ripening following which they are capable of surviving simulated digestion. This supports their potential for further development as candidate food-delivered probiotics.

Investigating the Impact of Ultrasound, Microwave, and High-Pressure Processing of Milk on the Volatile Compounds and Sensory Properties of Cheddar Cheese

Each cheese type has a unique flavor. A variety of compounds of various concentrations and different chemical classes contribute to this flavor. In the present study, the effect of processing techniques (ultrasonication (US), high pressure processing (HPP), microwave (MW)) on the flavors and sensory properties of milk and cheese was investigated. Samples of treated and untreated milk and cheese were analyzed for volatile compounds (including aldehydes, ketones, alcohols, fatty acids, and hydrocarbons). Significant variation was observed, and the results of sensory evaluation showed that cheese prepared from HPP and US-1 (21 J/g) secured higher sensory scores when compared to cheese prepared from US-2 (41 J/g), MW treatment, and the control. Variations in volatile profiles of milk and cheese were also evident according to the treatment process i.e., dodecanoic acid, octanoic acid, heptanoic acid, and nonanoic acid. Valeric acid was present only in US-1- (21 J/g) and US-2- (41 J/g) treated cheese, which is responsible for burnt and metallic flavors in milk and cheese. Butanoic acid, heptanal, heptanone, and butanediol were present in HPP, while ethyl butanoate, decanone, and 2,3-butanedione were present in microwave-treated milk. In a nutshell, the results of volatile compounds and sensory scores of cheeses are analogous, which shows that ultrasonication with high power output has some drawback because of the burnt and metallic flavor.

The linkage between international dairy commodity prices and volatility: a panel-GARCH analysis

PurposeThe study's purpose is to investigate the price volatility of four dairy commodities (skim milk powder [SMP], whole milk powder [WMP], butter and cheddar cheese) in the three most significant regional markets (EU, Oceania and US) in the international dairy market.Design/methodology/approachThe study uses a panel-Generalized Autoregressive Conditional Heteroskedastic (panel-GARCH) modeling technique and data from January 12, 2001, to April 28, 2017.FindingsConditional volatility was higher during subperiods 2007–2010 and 2014–2016 when conditional cross-correlations between prices had the lowest values. In some cases, they were negative (i.e. between the EU and the USA and between Oceania and the USA for both butter and cheese). Interdependence across the three dairy markets, especially for SMP and WMP markets and for the butter market between EU and Oceania is also strongly evidenced. Interdependence is responsible for the spillover of price shocks across the three regions.Research limitations/implicationsThe data set used should be extended to cover the COVID-19 pandemic period.Originality/valueThis is the first study to use panel-GARCH to examine international dairy prices and volatility linkages, where previous studies mainly used multivariate GARCH models. Panel-GARCH allows a high-dimensional data series (i.e. 12 dairy prices) and generates potential efficiency gains in estimating conditional variances and covariances by incorporating information about heterogeneity across markets and considering their interdependence.

Effect of skim milk addition and heat treatment on characteristics of cow milk Ricotta cheese manufactured from Cheddar cheese whey

The effect of varying levels of Cheddar cheese whey to skim milk (70:30, 80:20, 90:10) ratio and heat treatments (95, 90 and 85 °C holding for 10, 20 and 30 min each) on the properties of cow milk Ricotta cheese were investigated. The composition, yield, solids recoveries, colour, spreadability and sensory properties were significantly influenced. The composition and solids recoveries increased with increasing skim milk quantity and severity of heat treatment, but higher skim milk had adverse effect on colour, spreadability and sensorial acceptability. The lower proportion of skim milk (90:10) and higher heating temperature (95 °C) resulted in Ricotta with high moisture, fat, protein recovery, colour and spreadability and sensory acceptability, as also corroborated by principal component analysis (PCA). PCA extracted five principal components which explained 92.02% variance and grouped cheeses according to the level of cheese milk and heating temperature which are having similar properties. It is possible to produce whiter, uniform, easily spreadable, shiny, soft, creamy, granular, adhesive, and highly acceptable Ricotta from mixing 90 part of Cheddar whey and 10 parts skim milk in cheese milk and heat-treating at 95 °C/10 min. In this formulation, whey proteins denaturation and association with casein micelle were validated by RP-HPLC and SDS-PAGE.

Gas production by Paucilactobacillus wasatchensis WDCO4 is increased in Cheddar cheese containing sodium gluconate

Paucilactobacillus wasatchensis can use gluconate (GLCN) as well as galactose as an energy source and because sodium GLCN can be added during salting of Cheddar cheese to reduce calcium lactate crystal formation, our primary objective was to determine if the presence of GLCN in cheese is another risk factor for unwanted gas production leading to slits in cheese. A secondary objective was to calculate the amount of CO2 produced during storage and to relate this to the amount of gas-forming substrate that was utilized. Ribose was added to promote growth of Pa. wasatchensis WDC04 (P.waWDC04) to high numbers during storage. Cheddar cheese was made with lactococcal starter culture with addition of P.waWDC04 on 3 separate occasions. After milling, the curd was divided into six 10-kg portions. To the curd was added (A) salt, or salt plus (B) 0.5% galactose + 0.5% ribose (similar to previous studies), (C) 1% sodium GLCN, (D) 1% sodium GLCN + 0.5% ribose, (E) 2% sodium GLCN, (F) 2% sodium GLCN + 0.5% ribose. A vat of cheese without added P.waWDC04 was made using the same milk and a block of cheese used as an additional control. Cheeses were cut into 900-g pieces, vacuum packaged and stored at 12°C for 16 wk. Each month the bags were examined for gas production and cheese sampled and tested for lactose, galactose and GLCN content, and microbial numbers. In the control cheese, P.waWDC04 remained undetected (i.e., <104 cfu/g), whereas in cheeses A, C, and E it increased to 107 cfu/g, and when ribose was included with salting (cheeses B, D, and F) increased to 108 cfu/g. The amount of gas (measured as headspace height or calculated as mmoles of CO2) during 16 wk storage was increased by adding P.waWDC04 into the milk, and by adding galactose or GLCN to the curd. Galactose levels in cheese B were depleted by 12 wk while no other cheeses had residual galactose. Except for cheese D, the other cheeses with GLCN added (C, E and F) showed little decline in GLCN levels until wk 12, even though gas was being produced starting at wk 4. Based on calculations of CO2 in headspace plus CO2 dissolved in cheese, galactose and GLCN added to cheese curd only accounted for about half of total gas production. It is proposed that CO2 was also produced by decarboxylation of amino acids. Although P.waWDC04 does not have all the genes for complete conversion and decarboxylation of the amino acids in cheese, this can be achieved in conjunction with starter culture lactococcal. Adding GLCN to curd can now be considered another confirmed risk factor for unwanted gas production during storage of Cheddar cheese that can lead to slits and cracks in cheese. Putative risk factors now include having a community of bacteria in cheese leading to decarboxylation of amino acids and release of CO2 as well autolysis of the starter culture that would provide a supply of ribose that can promote growth of Pa. wasatchensis.

Production of Putrescine and Cadaverine by Paucilactobacillus wasatchensis.

Lactic acid bacteria (LAB) play a key role in many food fermentations. However, some LAB species can also cause food spoilage, e.g., through the formation of biogenic amines. Paucilactobacillus wasatchensis is a LAB that causes late gas production in Cheddar cheese, the molecular causes of which are not fully understood. This study reports on the ability of P. wasatchensis WDC04 to produce cadaverine and putrescine in broth supplemented with lysine and ornithine, as well as in a model cheese. The raclette-type semi-hard cheese produced with P. wasatchensis as an adjunct culture contained 1,085 mg kg−1 of cadaverine and 304 mg kg−1 of putrescine after 120 days of ripening. We identified two ornithine decarboxylase genes (odc) and a putrescine-ornithine antiporter gene (potE) in the genome sequence of P. wasatchensis. We could show that the two odc genes, which are located on two contigs, are contiguous and form the genetic cluster odc2-odc1-potE. Alignment searches showed that similar gene clusters exist in the genomes of Levilactobacillus paucivorans DSMZ22467, Lentilactobacillus kribbianus YH-lac9, Levilactobacillus hunanensis 151-2B, and Levilactobacillus lindianensis 220-4. More amino acid sequence comparisons showed that Odc1 and Odc2 shared 72 and 69% identity with a lysine and ornithine decarboxylase from Ligilactobacillus saerimneri 30a, respectively. To clarify the catalytic activities of both enzymes, the odc-coding genes were cloned and heterologously expressed as His-tagged fusion protein. The purified Odc1 protein decarboxylated lysine into cadaverine, while the recombinant Odc2 protein preferentially produced putrescine from ornithine but also exhibited low lysine decarboxylating activity. Both enzymes were active at pH of 5.5, a value often found in cheese. To our knowledge, this is only the second lysine decarboxylase in LAB whose function has been verified. The tandem arrangement of the genes in a single cluster suggests a gene duplication, evolving the ability to metabolize more amino. Divergent substrate preferences highlight the necessity of verifying the functions of genes, in addition to automatic annotation based on sequence similarity. Acquiring new biochemical data allows better predictive models and, in this case, more accurate biogenic amine production potential for LAB strains and microbiomes.

Suitability of a novel camel (Camelus dromedarius) chymosin as a coagulant for Cheddar cheese manufacture

Cheddar-type cheese was manufactured using fermentation-produced bovine chymosin (BC), fermentation-produced camel chymosin (CC) and a modified fermentation-produced camel chymosin (mCC) and ripened for 180 days. Only minor differences were found in cheese composition and pH between the cheeses made with any of the chymosins studied. Proteolysis in cheese made with mCC was reduced compared with cheese made with BC or CC. Significantly higher instrumental and sensory hardness and significantly lower meltability were found in cheeses made using CC or mCC compared with cheese BC after 180 days of ripening. Descriptive sensory analysis results showed that cheese made with CC or mCC had less sulphur and barny flavour; the brothy flavour and bitter taste of cheese made with mCC were also lowest. In conclusion, the modified camel chymosin appears to be suitable for the manufacture of Cheddar cheese with modified functionalities.