title: Ultrafiltered milk reduces bitterness in reduced-fat Cheddar cheese made with an exopolysaccharide-producing culture.
abstract: The objectives were to reduce bitterness in reduced-fat Cheddar cheese made with an exopolysaccharide (EPS)-producing culture and study relationships among ultra-filtration (UF), residual chymosin activity (RCA), and cheese bitterness. In previous studies, EPS-producing cultures improved the textural, melting, and viscoelastic properties of reduced-fat Cheddar cheese. However, the EPS-positive cheese developed bitterness after 2 to 3 mo of ripening due to increased RCA. We hypothesized that the reduced amount of chymosin needed to coagulate UF milk might result in reduced RCA and bitterness in cheese. Reduced-fat Cheddar cheeses were manufactured with EPS-producing and nonproducing cultures using skim milk or UF milk (1.2x) adjusted to a casein:fat ratio of 1.35. The EPS-producing culture increased moisture and RCA in reduced-fat Cheddar cheese. Lower RCA was found in cheese made from UF milk compared with that in cheese made from control milk. Ultrafiltration at a low concentration rate (1.2x) produced EPS-positive, reduced-fat cheese with similar RCA to that in the EPS-negative cheese. Slower proteolysis was observed in UF cheeses compared with non-UF cheeses. Panelists reported that UF EPS-positive cheese was less bitter than EPS-positive cheese made from control milk. This study showed that UF at a low concentration factor (1.2x) could successfully reduce bitterness in cheese containing a high moisture level. Because this technology reduced the RCA level (per g of protein) to a level similar to that in the control cheeses, the contribution of chymosin to cheese proteolysis would be similar in both cheeses.
authors.affiliation: Dairy Science Department, South Dakota State University, Brookings 57007, USA.
authors.forename: P
authors.initials: P
authors.lastname: Agrawal
authors.forename: A N
authors.initials: AN
authors.lastname: Hassan
mesh_terms: D000818:Animals; D002611:Cheese / Q000032:analysis / Q000592:standards*; D012085:Chymosin / Q000032:analysis; D015169:Colony Count, Microbial; D004041:Dietary Fats; D005516:Food Microbiology; D005524:Food Technology / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D013294:Lactococcus lactis / Q000378:metabolism*; D008892:Milk / Q000737:chemistry / Q000382:microbiology; D008894:Milk Proteins / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D013649:Taste; D014462:Ultrafiltration / Q000379:methods*
chemical_list: D004041:Dietary Fats; D008894:Milk Proteins; D011135:Polysaccharides, Bacterial; D012085:Chymosin; D009584:Nitrogen