The Effect of Fat Content on the Microbiology and Proteolysis in Cheddar Cheese During Ripening

Abstract

We investigated the effect of incremental reduction in fat content, in the range 33 to 6% (wt/wt), on changes in the microbiology and proteolysis of Cheddar cheese, over a 225-d ripening period at 7 degrees C. A reduction of fat content resulted in significant increases in contents of moisture and protein and a decrease in the concentration of moisture in nonfat substance. Reduced fat had little effect on the age-related changes in the population of starter cells. The populations of nonstarter lactic acid bacteria decreased with fat content, and counts in the low fat cheese (6% wt/wt) were significantly lower than those in the full fat cheese (33% wt/wt) at ripening times >1 and <180 d. Proteolysis as measured by the percentage of total N soluble at pH 4.6 or in 70% ethanol decreased significantly as the fat content decreased. However, the content of pH 4.6 soluble N per 100 g of cheese was not significantly influenced by fat content. At ripening times >60 d, the content of 70% ethanol soluble N per 100 g of full fat (33% wt/wt) cheese was significantly lower than that in either the half fat (17% wt/wt) or low fat (6% wt/wt) cheeses. The concentration of AA N, as a percentage of total N, was not significantly affected by fat content. However, when expressed as a percentage of total cheese, amino acid N increased significantly with decreasing fat content. Analysis of pH 4.6 soluble N extracts by reverse phase- and gel permeation HPLC revealed that fat content affected the pattern of proteolysis, as reflected by the differences in peptide profiles.

Measuring Cheese Maturation with the Fluorescence Fingerprint

“…However, these values are not only dependent on the maturation time but are known to also be affected by fat content (Fenelon et al, 2000), temperature, salting, pH of the curd and humidity (Jin and Park, 1995). Consequently, the proteolysis index and total free amino acids could not be sufficiently predicted solely from maturation time.…”

Heterologous Expression of Lactose- and Galactose-Utilizing Pathways from Lactic Acid Bacteria in Corynebacterium glutamicum for Production of Lysine in Whey

“…The procedure for analyzing free amino acids in whey-based medium was based on the method previously described by Fenelon et al (7). Samples for amino acid analysis were extracted from whey-based medium during or following growth of C. glutamicum strains, and assays were performed in duplicate.…”

Microbiology of Cheddar cheese made with different fat contents using a Lactococcus lactis single-strain starter

“…This knowledge has served industry efforts to promote flavor development in many traditional cheese varieties, but efforts to extend it to low-fat Cheddar (LFC) cheese has proven to be difficult. As a result, LFC varieties continue to suffer from low intensity of desirable flavor such as buttery, creamy, or caramel, and commonly develop pronounced meaty-brothy or burnt-brothy offflavors (Milo and Reineccius, 1997;Fenelon et al, 2000;Drake et al, 2010).…”