The evolution of Cheddar cheese flavor and texture is highly dependent on its proteolytic state however, Cheddar cheese is marketed based on its chronological age. Information about the proteolytic age of commercial Cheddar cheese of a given age almost does not exist. The present research challenged the merit of marketing Cheddar cheese according to its chronological age. Full-fat (FF) and Reduced-fat (RF) Cheddar cheeses, of identical chronological age, were aged for 180 days at 5 ℃ and the progression of the proteolytic cascade was investigated and quantified. The accumulation of the cheese N fractions that are soluble at pH 4.6 (4.6SN), soluble in 12% tri-chloroacetic acid (12TCASN), and soluble in 5% phospho-tungstic acid (5PTASN) was quantified along with the accumulation of free L-Glutamic acid (L-Glu). Results indicated that both FF and RF cheeses exhibited very significant among-cheeses differences in accumulation of the investigated fractions (p < 0.05). These significant differences were related to both the concentration of the fractions and the rate at which they accumulated. The results thus reflected significant among-cheeses differences in the inherent proteolytic potential of the cheeses as well as in its manifestation during aging. Results clearly indicated that the chronological age of the investigated cheeses did not reflect their proteolytic age. The results highlighted the need to market Cheddar cheese based on some proteolysis-related quantitative parameters.

Effective approaches for modulating the evolution of cheese quality attributes are needed for mitigating challenges that are associated with fluctuating supply and demand as well as with disrupt supply chain. Proteolysis is the most important and most complex cascade of events that affects the evolution of cheese quality attributes. Information about the effects of small changes in temperature during isothermal and non-isothermal aging of Cheddar cheese at temperatures lower than 10 ℃ on proteolysis has been developed to a very limited extent. The objective of the research was to age FF and RF Cheddar cheeses for six months at different isothermal and non-isothermal time-at-temperature regimes at temperature ranging from 5 to 8 ℃ and to investigate the effects of these conditions on proteolysis. Changes in the level of cheese-N fractions that are soluble at pH 4.6, soluble in 12% TCA and soluble in 5% PTA were monitored. The proteolytic cascade during aging was significantly (p < 0.05) influenced by a combined impact of the time-at-temperature details of aging and cheese composition. The highest and lowest levels of the investigated fractions were found in cheeses that had been aged isothermally at 8 and 5 ℃, respectively. In most cases, proteolysis in the FF cheeses was to a higher extent than in the RF ones. Proteolysis during non-isothermal aging was significantly affected by the aging regime in a time-at-temperature-specific manner (p < 0.05). The results can offer new opportunities for modulating the rate of cheese aging. The demonstrated significant effect of a very small change in aging temperature on proteolysis during cheese aging also highlights the critical importance of establishing and maintaining isotropic temperature distribution in cheese aging rooms.