First pigment fingerprints from the rind of French PDO red-smear ripened soft cheeses Epoisses, Mont d'Or and Maroilles

Biomarkers of food intake and their relevance to metabolic syndrome

Metabolic syndrome (MetS) constitutes a prevalent risk factor associated with non communicable diseases such as cardiovascular disease and type 2 diabetes. A major factor impacting the etiology of MetS is diet. Dietary patterns and several individual food constituents have been related to the risk of developing MetS or have been proposed as adjuvant treatment. However, traditional methods of dietary assessment such as 24 h recalls rely greatly on intensive user-interaction and are subject to bias. Hence, more objective methods are required for unbiased dietary assessment and efficient prevention. While it is accepted that some dietary-derived constituents in blood plasma are indicators for certain dietary patterns, these may be too unstable (such as vitamin C as a marker for fruits/vegetables) or too broad (e.g. polyphenols for plant-based diets) or reflect too short-term intake only to allow for strong associations with prolonged intake of individual food groups. In the present manuscript, commonly employed biomarkers of intake including those related to specific food items (e.g. genistein for soybean or astaxanthin and EPA for fish intake) and novel emerging ones (e.g. stable isotopes for meat intake or microRNA for plant foods) are emphasized and their suitability as biomarker for food intake discussed. Promising alternatives to plasma measures (e.g. ethyl glucuronide in hair for ethanol intake) are also emphasized. As many biomarkers (i.e. secondary plant metabolites) are not limited to dietary assessment but are also capable of regulating e.g. anti-inflammatory and antioxidant pathways, special attention will be given to biomarkers presenting a double function to assess both dietary patterns and MetS risk.

Purification, Identification, and Properties of a Novel Carotenoid Produced by Arthrobacter sp. QL17 Isolated from Mount Qomolangma

The genus Arthrobacter is a source of many natural products that are critical in the development of new medicines. Here, we isolated a novel carotenoid from Arthrobacter sp. QL17 and characterized its properties. The carotenoid was extracted with methanol, and purified by column chromatography and semi-preparative HPLC. Based on micrOTOF-Q and NMR analyses, the pigment was chemically characterized as 2,2′-((((1E,3E,5E,7E,9E,11E,13E,15E,17E,19E)-3,7,14,18-tetramethylicosa-1,3,5,7,9,11,13,15,17,19-decaene-1,20-diyl)bis(2,2,4-trimethylcyclohex-3-ene-3,1-diyl)) bis(ethan-2-yl-1-ylidene))bi(propane-1,3-diol), and named arthroxanthin. The biological activities of arthroxanthin were evaluated with DPPH, ABTS and MTT assays. Arthroxanthin exhibited excellent radical scavenging properties, as shown for 2, 20-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-n-(3, 2-ethyl-benzothiazole-6-sulfonic acid) ammonium salt (ABTS), respectively, with IC50s of 69.8 and 21.5 µg/mL. It also showed moderate anticancer activities against HepG2, Hela, MDAB-231, SW480, and MKN-45 with IC50 values of 107.6, 150.4, 143.4, 195.9, and 145.5 μg/mL, respectively. Therefore, arthroxanthin derived from Arthrobacter sp. QL17 may be a potent antioxidant and anticancer agent for food and pharmaceutical use.

Temporal differences in microbial composition of Époisses cheese rinds during ripening and storage

Époisses is a protected designation of origin smear-ripened cheese from the Burgundy region in France. It has an orange color and a strong flavor, both of which are generated by surface microorganisms. The objective of the present study was to investigate the microbial dynamics at the surface of Époisses cheese during ripening and postmanufacturing storage at low temperatures. Rind samples were analyzed by enumeration on agar plates and by 16S rRNA gene and internal transcribed spacer amplicon sequencing. During most of the ripening process, the counts of yeasts, which corresponded to the species Debaryomyces hansenii and Geotrichum candidum, were higher than those of the aerobic acid-sensitive bacteria. Debaryomyces hansenii reached a level of about 3 × 10⁸ cfu/cm², and its viability strongly decreased in the late stage of ripening and during storage at 4°C. Two of the inoculated bacterial species, Brevibacterium aurantiacum and Staphylococcus xylosus, did not establish themselves at the cheese surface. At the end of ripening, among the 18 most abundant bacterial species detected by amplicon sequencing, 14 were gram-negative, mainly from genera Psychrobacter, Vibrio, Halomonas, and Mesonia. It was hypothesized that the high moisture level of the Époisses rinds, due the humid atmosphere of the ripening rooms and to the frequent washings of the curds, favored growth of these gram-negative species. These species may be of interest for the development of efficient ripening cultures. In addition, because the orange color of Époisses cheeses could not be attributed to the growth of Brevibacterium, it would be interesting to investigate the type and origin of the pigments that confer color to this cheese.

Comparison of the carotenoid profiles of commonly consumed smear-ripened cheeses

The objective of this study was to identify the carotenoids imparting the orange colour to the rind, and pale yellow color to the core, of selected smear-ripened cheeses. The cheeses investigated were Charloe, Ashbrook, Taleggio, and Limburger, and were sourced from artisanal markets. Samples of the rind and core were extracted using non-polar solvents, followed by saponification to hydrolyze triglycerides to remove fatty acids, and to release carotenoid esters. Extracts were tested using ultra-high pressure liquid chromatograph-diode array detector-high resolution mass spectrometry (UHPLC-DAD-MS and -MS/MS), and identities of α- and β-carotene, lycopene, and β-cryptoxanthin confirmed with authentic standards. β-Carotene was the predominant species in both the rind and core, absorbing ~70% of the signal at 450 nm in all cheese extracts tested, as well as minor quantities of β-cryptoxanthin and α-carotene. Carotenoids unique to the rind included lycopene as well as the rare bacterial carotenoids previously identified in bacterial isolates of cheeses (i.e. decaprenoxanthin, sarcinaxanthin, and echinenone). This is the first detailed characterisation of carotenoids extracted directly from smear-ripened cheeses, and reveals that smear-ripened cheese can contribute both provitamin A carotenoids as well as C50 carotenoids to the human diet.

Biotechnological approaches for the production of designer cheese with improved functionality

Cheese is a product of ancient biotechnological practices, which has been revolutionized as a functional food product in many parts of the world. Bioactive compounds, such as peptides, polysaccharides, and fatty acids, have been identified in traditional cheese products, which demonstrate functional properties such as antihypertensive, antioxidant, immunomodulation, antidiabetic, and anticancer activities. Besides, cheese-making probiotic lactic acid bacteria (LAB) exert a positive impact on gut health, aiding in digestion, and improved nutrient absorption. Advancement in biotechnological research revealed the potential of metabolite production with prebiotics and bioactive functions in several strains of LAB, yeast, and filamentous fungi. The application of specific biocatalyst producing microbial strains enhances nutraceutical value, resulting in designer cheese products with multifarious health beneficial effects. This review summarizes the biotechnological approaches applied in designing cheese products with improved functional properties.

The Good, the Bad, and the Ugly: Tales of Mold-Ripened Cheese

The history of cheese manufacture is a "natural history" in which animals, microorganisms, and the environment interact to yield human food. Part of the fascination with cheese, both scientifically and culturally, stems from its ability to assume amazingly diverse flavors as a result of seemingly small details in preparation. In this review, we trace the roots of cheesemaking and its development by a variety of human cultures over centuries. Traditional cheesemakers observed empirically that certain environments and processes produced the best cheeses, unwittingly selecting for microorganisms with the best biochemical properties for developing desirable aromas and textures. The focus of this review is on the role of fungi in cheese ripening, with a particular emphasis on the yeast-like fungus Geotrichum candidum. Conditions that encourage the growth of problematic fungi such as Mucor and Scopulariopsis as well as Arachnida (cheese mites), and how such contaminants might be avoided, are discussed. Bethlehem cheese, a pressed, uncooked, semihard, Saint-Nectaire-type cheese manufactured in the United Sates without commercial strains of bacteria or fungi, was used as a model for the study of stable microbial succession during ripening in a natural environment. The appearance of fungi during a 60-day ripening period was documented using light and scanning electron microscopy, and it was shown to be remarkably reproducible and parallel to the course of ripening of authentic Saint-Nectaire cheese in the Auvergne region of France. Geotrichum candidum, Mucor, and Trichothecium roseum predominate the microbiotas of both cheese types. Geotrichum in particular was shown to have high diversity in different traditional cheese ripening environments, suggesting that traditional manufacturing techniques selected for particular fungi. This and other studies suggest that strain diversity arises in relation to the lore and history of the regions from which these types of cheeses arose.

A screening method of oil-soluble synthetic dyes in chilli products based on multi-wavelength chromatographic fingerprints comparison

A multi-wavelength HPLC fingerprint comparison method was proposed for the screening of oil-soluble synthetic dyes in chilli products. The screening was based on the fingerprint differences of normal unadulterated chilli sample with tested chilli samples. The samples were extracted with acetone and fingerprinted by HPLC under four visible light wavelengths (450 nm, 490 nm, 520 nm, and 620 nm). It was found that the fingerprints of different chilli product samples had a relatively fixed number of peaks and stable retention time. When 16 kinds of known synthetic dyes were used as model analytes to assess the screening efficiency, 14 of them could be screened using fingerprint comparison method, with LOD of 0.40-2.41 mg/kg. The new screening method was simple and had the possibility of finding existence of the adulterated dyes which could not be identified using known standard analytes as control.

Production of carotenoids by Arthrobacter arilaitensis strains isolated from smear-ripened cheeses

Arthrobacter arilaitensis is one of the major microorganisms responsible for the coloration of cheese surface, particularly in smear-ripened cheeses. This study investigated the occurrence of pigment synthesis among A. arilaitensis strains in several aspects covering (1) UV-Vis absorption spectra and HPLC chromatograms of pigment extracts, (2) diversity of pigment production among strains, (3) influence of light on the production of pigment, and (4) kinetic of pigment synthesis. Based on absorption spectra and HPLC analysis, the 14 A. arilaitensis strains studied could be divided into two groups depending on their ability to produce carotenoids, carotenoid-producing, and nonpigmented strains. The methanolic extracts prepared from eight carotenoid-producing strains contained at least four carotenoids represented mainly as polar molecules. The diversity of pigment concentrations among these strains was low, with carotenoids ranging from 0.40 to 0.76 mg L(-1) culture and specific productivities from 0.14 to 0.25 mg pigment per g dry biomass, under light condition. When cultivating these A. arilaitensis strains under darkness condition, carotenoid biosynthesis was lower within a 0.17-0.25 mg L(-1) range. The pigment production time curve of a representative colored A. arilaitensis strain displayed a sigmoid shape which paralleled cell growth, probably indicating a growth-associated pigmentation.

The arthrobacter arilaitensis Re117 genome sequence reveals its genetic adaptation to the surface of cheese

Arthrobacter arilaitensis is one of the major bacterial species found at the surface of cheeses, especially in smear-ripened cheeses, where it contributes to the typical colour, flavour and texture properties of the final product. The A. arilaitensis Re117 genome is composed of a 3,859,257 bp chromosome and two plasmids of 50,407 and 8,528 bp. The chromosome shares large regions of synteny with the chromosomes of three environmental Arthrobacter strains for which genome sequences are available: A. aurescens TC1, A. chlorophenolicus A6 and Arthrobacter sp. FB24. In contrast however, 4.92% of the A. arilaitensis chromosome is composed of ISs elements, a portion that is at least 15 fold higher than for the other Arthrobacter strains. Comparative genomic analyses reveal an extensive loss of genes associated with catabolic activities, presumably as a result of adaptation to the properties of the cheese surface habitat. Like the environmental Arthrobacter strains, A. arilaitensis Re117 is well-equipped with enzymes required for the catabolism of major carbon substrates present at cheese surfaces such as fatty acids, amino acids and lactic acid. However, A. arilaitensis has several specificities which seem to be linked to its adaptation to its particular niche. These include the ability to catabolize D-galactonate, a high number of glycine betaine and related osmolyte transporters, two siderophore biosynthesis gene clusters and a high number of Fe(3+)/siderophore transport systems. In model cheese experiments, addition of small amounts of iron strongly stimulated the growth of A. arilaitensis, indicating that cheese is a highly iron-restricted medium. We suggest that there is a strong selective pressure at the surface of cheese for strains with efficient iron acquisition and salt-tolerance systems together with abilities to catabolize substrates such as lactic acid, lipids and amino acids.

The type of cheese curds determined the colouring capacity of Brevibacterium and Arthrobacter species

This study compares the colouring capacity of Brevibacterium aurantiacum (BA), Brevibacterium BL and Arthrobacter species AS in relation to deacidified media made from lactic curd (Epoisses), mixed curds (Munster) and rennet curds (Livarot or Reblochon). BA colouring capacity proved to be constant, leading to a dark orange colour, irrespective of the deacidified media. However, it gave too dark a colour for Reblochon. The strains BL and AS were not adapted to the colouring of Epoisses deacidified medium. On the Livarot or Munster deacidified medium, these two strains provided a light yellow orange colour range that was not suitable for these cheeses. However, these two strains (BL and AS) produced a suitable colour for Reblochon deacidified medium.

Microbial interactions in cheese: implications for cheese quality and safety

The cheese microbiota, whose community structure evolves through a succession of different microbial groups, plays a central role in cheese-making. The subtleties of cheese character, as well as cheese shelf-life and safety, are largely determined by the composition and evolution of this microbiota. Adjunct and surface-ripening cultures marketed today for smear cheeses are inadequate for adequately mimicking the real diversity encountered in cheese microbiota. The interactions between bacteria and fungi within these communities determine their structure and function. Yeasts play a key role in the establishment of ripening bacteria. The understanding of these interactions offers to enhance cheese flavour formation and to control and/or prevent the growth of pathogens and spoilage microorganisms in cheese.