title: Effect of sodium, potassium, magnesium, and calcium salt cations on pH, proteolysis, organic acids, and microbial populations during storage of full-fat Cheddar cheese.
abstract: Sodium reduction in cheese can assist in reducing overall dietary Na intake, yet saltiness is an important aspect of cheese flavor. Our objective was to evaluate the effect of partial substitution of Na with K on survival of lactic acid bacteria (LAB) and nonstarter LAB (NSLAB), pH, organic acid production, and extent of proteolysis as water-soluble nitrogen (WSN) and protein profiles using urea-PAGE, in Cheddar cheese during 9mo of storage. Seven Cheddar cheeses with molar salt contents equivalent to 1.7% salt but with different ratios of Na, K, Ca, and Mg cations were manufactured as well as a low-salt cheese with 0.7% salt. The 1.7% salt cheeses had a mean composition of 352g of moisture/kg, 259g of protein/kg and 50% fat-on-dry-basis, and 17.5g of salt/kg (measured as Cl(-)). After salting, a faster initial decrease in cheese pH occurred with low salt or K substitution and it remained lower throughout storage. No difference in intact casein levels or percentage WSN levels between the various cheeses was observed, with the percentage WSN increasing from 5% at d 1 to 25% at 9mo. A greater decrease in intact αs1-casein than β-casein was detected, and the ratio of αs1-casein (f121-199) to αs1-casein could be used as an index of ripening. Typical changes in bacteria microflora occurred during storage, with lactococci decreasing gradually and NSLAB increasing. Lowering the Na content, even with K replacement, extended the crossover time when NSLAB became dominant. The crossover time was 4.5mo for the control cheese and was delayed to 5.2, 6.0, 6.1, and 6.2mo for cheeses with 10, 25, 50, and 75% K substitution. Including 10% Mg or Ca, along with 40% K, further increased crossover time, whereas the longest crossover time (7.3mo) was for low-salt cheese. By 9mo, NSLAB levels in all cheeses had increased from initial levels of ≤10(2) to approximately 10(6)cfu/g. Lactococci remained at 10(6) cfu/g in the low-salt cheese even after 9mo of storage. The propionic acid concentration in the cheese increased when NSLAB numbers were high. Few other trends in organic acid concentration were observed as a function of Na content.
authors.affiliation: Western Dairy Center, Utah State University, Logan 84322. Electronic address: Donald.McMahon@usu.edu.
authors.forename: D J
authors.initials: DJ
authors.lastname: McMahon
authors.affiliation: Western Dairy Center, Utah State University, Logan 84322; Department of Microbiology, Weber State University, Ogden, UT 84408.
authors.forename: C J
authors.initials: CJ
authors.lastname: Oberg
authors.affiliation: Southeast Dairy Foods Research Center, North Carolina State University, Raleigh 27695.
authors.forename: M A
authors.initials: MA
authors.lastname: Drake
authors.affiliation: Dairy Products Technology Center, California Polytechnic State University, San Luis Obispo 93407.
authors.forename: N
authors.initials: N
authors.lastname: Farkye
authors.affiliation: Department of Microbiology, Weber State University, Ogden, UT 84408.
authors.forename: L V
authors.initials: LV
authors.lastname: Moyes
authors.affiliation: Dairy Products Technology Center, California Polytechnic State University, San Luis Obispo 93407.
authors.forename: M R
authors.initials: MR
authors.lastname: Arnold
authors.affiliation: Western Dairy Center, Utah State University, Logan 84322.
authors.forename: B
authors.initials: B
authors.lastname: Ganesan
authors.affiliation: Department of Food Science, University of Wisconsin, Madison 53705.
authors.forename: J
authors.initials: J
authors.lastname: Steele
authors.affiliation: Western Dairy Center, Utah State University, Logan 84322.
authors.forename: J R
authors.initials: JR
authors.lastname: Broadbent
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000818:Animals; D002118:Calcium / Q000737:chemistry*; D002364:Caseins / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D002611:Cheese / Q000032:analysis* / Q000382:microbiology*; D015169:Colony Count, Microbial; D003258:Consumer Behavior; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D061353:Food Storage; D005561:Formates / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry; D017045:Lactococcus / Q000302:isolation & purification; D008274:Magnesium / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry; D059748:Proteolysis; D012964:Sodium / Q000737:chemistry*; D012965:Sodium Chloride / Q000378:metabolism; D013649:Taste
chemical_list: D002364:Caseins; D002412:Cations; D005561:Formates; D011422:Propionates; C030544:formic acid; D019344:Lactic Acid; D012965:Sodium Chloride; D012964:Sodium; D008274:Magnesium; D019342:Acetic Acid; D011188:Potassium; D002118:Calcium
keywords: cheese; nonstarter; potassium; propionic acid; sodium