Galactose concentration in pizza cheese prepared by three different culture techniques

Baskaran, D; Sivakumar, S

doi:10.1046/j.1471-0307.2003.00109.x

Cited by 11 publications

(6 citation statements)

References 6 publications

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“…The presence of galactose has been associated with shoddier qualities of the fermented product (6,27,43). In particular, galactose is a major contributor to the browning that occurs when dairy products (e.g., yogurt and mozzarella, Swiss, and cheddar cheese) are cooked or heated in the manufacture of pizzas, sauce preparation, or processed cheese.…”

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confidence: 99%

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Towards Enhanced Galactose Utilization by Lactococcus lactis

Neves

Pool

Solopova

et al. 2010

Appl Environ Microbiol

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Accumulation of galactose in dairy products due to partial lactose fermentation by lactic acid bacteria yields poor-quality products and precludes their consumption by individuals suffering from galactosemia. This study aimed at extending our knowledge of galactose metabolism in Lactococcus lactis, with the final goal of tailoring strains for enhanced galactose consumption. We used directed genetically engineered strains to examine galactose utilization in strain NZ9000 via the chromosomal Leloir pathway (gal genes) or the plasmid-encoded tagatose 6-phosphate (Tag6P) pathway (lac genes). Galactokinase (GalK), but not galactose permease (GalP), is essential for growth on galactose. This finding led to the discovery of an alternative route, comprising a galactose phosphotransferase system (PTS) and a phosphatase, for galactose dissimilation in NZ9000. Introduction of the Tag6P pathway in a galPMK mutant restored the ability to metabolize galactose but did not sustain growth on this sugar. The latter strain was used to prove that lacFE, encoding the lactose PTS, is necessary for galactose metabolism, thus implicating this transporter in galactose uptake. Both PTS transporters have a low affinity for galactose, while GalP displays a high affinity for the sugar. Furthermore, the GalP/Leloir route supported the highest galactose consumption rate. To further increase this rate, we overexpressed galPMKT, but this led to a substantial accumulation of ␣-galactose 1-phosphate and ␣-glucose 1-phosphate, pointing to a bottleneck at the level of ␣-phosphoglucomutase. Overexpression of a gene encoding ␣-phosphoglucomutase alone or in combination with gal genes yielded strains with galactose consumption rates enhanced up to 50% relative to that of NZ9000. Approaches to further improve galactose metabolism are discussed.Lactococcus lactis is a lactic acid bacterium widely used in the dairy industry for the production of fermented milk products. Because of its economic importance, L. lactis has been studied extensively in the last 40 years. A small genome, a large set of genetic tools, a wealth of physiological knowledge, and a relatively simple metabolic potential render L. lactis an attractive model with which to implement metabolic engineering strategies (reviewed in references 21 and 57).In the process of milk fermentation by L. lactis, lactose is taken up and concomitantly phosphorylated at the galactose moiety (C-6) by the lactose-specific phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS Lac ), after which it is hydrolyzed to glucose and galactose 6-phosphate (Gal6P) (64). The glucose moiety enters the glycolytic pathway upon phosphorylation via glucokinase to glucose 6-phosphate (G6P), whereas Gal6P is metabolized to triose phosphates via the D-tagatose 6-phosphate (Tag6P) pathway, encompassing the steps catalyzed by galactose 6-phosphate isomerase (LacAB), Tag6P kinase (LacC), and tagatose 1,6-bisphosphate aldolase (LacD) (Fig. 1). Curiously, during the metabolism of lactose by L. lactis, part of the Gal...

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confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] C]galactose (99% enrichment) was obtained from Euriso-top (Gif-Sur-Yvette, France). Formic acid (sodium salt) was purchased from Merck Sharp & Dohme (Whitehouse Station, NJ).…”

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Towards Enhanced Galactose Utilization by Lactococcus lactis

Neves

Pool

Solopova

et al. 2010

Appl Environ Microbiol

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“…Because of the substantial biotechnological relevance of galactose, especially in the dairy industry, where unmetabolized galactose is associated with poor product quality (Baskaran & Sivakumar, ; Hutkins, Halambeck, & Morris, ; Michel & Martley, ), galactose metabolism and its regulation have been thoroughly studied in several LAB species. The crucial role of the Leloir pathway in the utilization of nonphosphorylated galactose is well documented.…”

Section: Discussionmentioning

confidence: 99%

“…Because of the substantial biotechnological relevance of galactose, especially in the dairy industry, where unmetabolized galactose is associated with poor product quality (Baskaran & Sivakumar, 2003;Hutkins, Halambeck, & Morris, 1986;Michel & Martley, 2001) (Yamamoto, Serizawa, Thompson, & Sekiguchi, 2001), HexR, IolR, MurR, and RpiR act as repressors of glucose, inositol, N-acetylmuramic acid, ribose or central carbon metabolism in several gram-negative bacteria (Antunes et al, 2016;Jaeger & Mayer, 2008;Kohler, Choong, & Rossbach, 2011;Sørensen & Hove-Jensen, 1996), and HexR is a dual-mode pleiotropic regulator of the central carbohydrate metabolism in proteobacteria (Leyn et al, 2011). Thus far, none of the RpiR regulators has been implicated in modulating galactose metabolism.…”

Section: Discussionmentioning

confidence: 99%

GlaR (YugA)—a novel RpiR‐family transcription activator of the Leloir pathway of galactose utilization in Lactococcus lactis IL1403

Aleksandrzak‐Piekarczyk

Szatraj

Kosiorek

2018

MicrobiologyOpen

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Bacteria can utilize diverse sugars as carbon and energy source, but the regulatory mechanisms directing the choice of the preferred substrate are often poorly understood. Here, we analyzed the role of the YugA protein (now designated GlaR-Galactose-lactose operon Regulatory protein) of the RpiR family as a transcriptional activator of galactose (gal genes) and lactose (lac genes) utilization genes in Lactococcus lactis IL1403. In this bacterium, gal genes forming the Leloir operon are combined with lac genes in a single so-called gal-lac operon. The first gene of this operon is the lacS gene encoding galactose permease. The glaR gene encoding GlaR lies directly upstream of the gal-lac gene cluster and is transcribed in the same direction. This genetic layout and the presence of glaR homologues in the closest neighborhood to the Leloir or gal-lac operons are highly conserved only among Lactococcus species. Deletion of glaR disabled galactose utilization and abrogated or decreased expression of the gal-lac genes. The GlaR-dependent regulation of the gal-lac operon depends on its specific binding to a DNA region upstream of the lacS gene activating lacS expression and increasing the expression of the operon genes localized downstream. Notably, expression of lacS-downstream genes, namely galMKTE, thgA and lacZ, is partially independent of the GlaR-driven activation likely due to the presence of additional promoters. The glaR transcription itself is not subject to catabolite control protein A (CcpA) carbon catabolite repression (CRR) and is induced by galactose. Up to date, no similar mechanism has been reported in other lactic acid bacteria species. These results reveal a novel regulatory protein and shed new light on the regulation of carbohydrate catabolism in L. lactis IL1403, and by similarity, probably also in other lactococci.

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“…Indeed, galactose accumulation in the cheese leads to excessive browning of the cheese during baking of the pizza due to the Maillard reaction [3].…”

Section: The Low Moisture Part Skimmentioning

confidence: 99%

Processing of Mozzarella cheese wheys and stretchwaters: A preliminary review

Gernigon

Schuck

Jeantet

2009

Dairy Sci. Technol.

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-Mozzarella cheese is one of the cheeses that has achieved the most significant growth in production in the past century. This has resulted in the concomitant production of large amounts of whey and (in the case of Mozzarella cheese) stretchwater. For decades, these products were often dumped as waste products or used as animal feed. However, it is no longer possible to do so. First, these by-products have a high oxygen demand, and thus a great environmental impact. Second, the high nutritional value of their constituents (whey protein, lactose, etc.) makes it necessary to make use of these products and, as food ingredients, this begins with concentration and spray drying of the bulk material. These stages are known to be especially difficult in the case of Mozzarella cheese wheys and stretchwaters, and there is thus a need to study and explain the role of the minor compounds that were found in Mozzarella cheese wheys, including water-binding properties and low glass transition temperature. Solving these problems requires a good understanding of the origins of these by-products (i.e. Mozzarella cheese making) and of water dynamics. The aim of this review is to provide an overview of the current knowledge on the composition of Mozzarella cheese wheys and stretchwaters, their origin in cheese making and the possible implications of their composition on the different water elimination stages.Mozzarella cheese / whey / spray drying / water dynamics / pasta filataRésumé -Traitement des lactosérums et des eaux de filage de Mozzarelle -revue prélimi-naire. La Mozzarella est l'un des fromages dont la production a connu la plus forte progression ces cinquante dernières années. Une telle évolution s'accompagne inévitablement d'une production croissante de coproduits, le lactosérum et l'eau de filage. Pendant des décennies, ces coproduits *Corresponding author (通讯作者): pierre.schuck@rennes.inra.fr Dairy Sci. Technol. 90 (2010) 27-46

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Galactose concentration in pizza cheese prepared by three different culture techniques

Cited by 11 publications

References 6 publications

Towards Enhanced Galactose Utilization by Lactococcus lactis

Towards Enhanced Galactose Utilization by Lactococcus lactis

GlaR (YugA)—a novel RpiR‐family transcription activator of the Leloir pathway of galactose utilization in Lactococcus lactis IL1403

Processing of Mozzarella cheese wheys and stretchwaters: A preliminary review

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