Effect of Adding Propionibacterium shermanii NCDO 853 or Lactobacillus casei ssp. casei IFPL 731 on Proteolysis and Flavor Development of Cheddar Cheese

Abstract

Proteolysis and flavor development were monitored in Cheddar cheese made from milk inoculated with Lactobacillus casei ssp. casei IFPL 731 (104 cfu/mL cheesemilk) or Propionibacterium shermanii NCDO 853 at three different levels (105, 106, and 107 cfu/mL cheesemilk). The pH and chemical composition of the experimental cheeses were not affected by the addition of L. casei or Prop. shermanii. Cheeses inoculated with L. casei or Prop. shermanii at low and medium levels received the best scores for flavor development and body. However, the addition of Prop. shermanii at a high level caused a sweet and nutty flavor. Urea-PAGE, WSN, and RP-HPLC showed minor differences in proteolysis between the control and experimental cheeses. Major differences were found at the amino acid level. In general, the content of amino acid increased as the Propionibacterium inoculum increased in the experimental cheeses. Besides, a decrease in the content of hydrophobic peptides was observed in cheeses inoculated with Prop. shermanii at medium and high levels. The increase in amino acid content was not apparent when L. casei was added to cheese, possibly due to the lack of cell lysis. There is an optimum inoculum level of Prop. shermanii above which the flavor of Cheddar cheese resembles that of Swiss-type cheese. Keywords: Propionibacterium shermanii; Lactobacillus casei ssp. casei; adjunct cultures; Cheddar cheese; proteolysis

Isolation and characterization of proline iminopeptidase fromPropionibacterium freudenreichii ATCC 9614

“…The population of propionic acid bacteria in Emmentaler cheese reaches 10 9 /g [7]. Propionibacteria also increased the concentration of free amino acids and improved flavour in experimental Cheddar cheese [7].…”

“…The pH, composition and volume of the incubation mixture were the same as used to measure PIP activity. The cadmium-ninhydrin method of Doi et al [5], as modified by Fernández-Esplá and Fox [7], was used to measure activity on dipeptides after incubation for 60 min at 40 8C A dimeric, 90 kDa subunit intracellular proline iminopeptidase from Propionibacterium freudenreichii ATCC 9614 was purified to homogeneity by chromatography on hydroxyapatite, Sephacryl 200, Phenyl Superose and Mono Q. The enzyme was specific on Pro-p-nitroanilide and Pro-X dipeptides.…”

“…Propionic acid bacteria are important for flavour development and eye formation in Swiss-type and Norwegian Jarlsberg cheeses [7,18]. Although little proteolysis has been attributed to propionibacteria, model studies with cheese curd revealed that the cytoplasmic fraction of Propionibacterium freudenreichii can influence significantly the pattern of peptides when added to curd containing rennet and intracellular proteolytic enzymes from lactococci and lactobacilli [18].…”

“…A relationship has been postulated between the typical taste of Swiss cheeses and the high concentration (150 -600 mg/100 g) of proline produced by propionic acid bacteria [14]. The population of propionic acid bacteria in Emmentaler cheese reaches 10 9 /g [7]. Propionibacteria also increased the concentration of free amino acids and improved flavour in experimental Cheddar cheese [7].…”

The role of propionibacteria in the volatile profile of Pategrás cheeses

“…In these cheeses, PAB are often added to milk as adjunct cultures, but sometimes they are indigenous to the raw milk (Beuvier et al 1997;Thierry et al 2005a). Propionibacterium species can also be used in the manufacture of some cheeses without eyes to enhance flavor formation (Fernandez-Espla and Fox 1998;Thierry et al 2005a). In addition to the ability to ferment lactic acid to acetic and propanoic acids, more recently, PAB have been demonstrated to play a key role in the formation of free fatty acids and several branched-chain volatile compounds (Thierry et al 2011).…”