Dairy Foods: Impact of Salt Reduction on Cheese

Low fat (LF) cheddar cheese develops flavor during aging uncharacteristic of full fat (FF) cheese, such as rosey and burnt/brothy flavors and bitter taste. Our objective was to determine if this is a function of differences in salt-in-moisture (S/M) content. Full fat and LF curd was made (in triplicate) using 700 kg of milk and salted to produce cheese with S/M typical of LF cheese. Half the curd was pressed into blocks, and further salt was added to the remainder to make cheese with S/M typical of FF cheese. For FF cheese, high salt (HS) levels were 2.1– 2.5% salt (5.4–6.4% S/M) and low salt (LS) levels were 1.4–1.6% (3.5–4.0% S/M). For LF cheese, HS levels were 2.4–3.1% (4.3–5.6% S/M) and LS levels were 1.6–2.0% (3.0–3.6% S/M). Cheese was stored at 6°C and analyzed monthly for total lactic acid bacteria (LAB), lactococci, and nonstarter LAB (NSLAB) using selective media. Sensory profiles and volatile compounds of cheeses were analyzed after 2, 5 and 7 mo using descriptive sensory analysis and gas chromatography mass spectrometry. In general, initial NSLAB levels were < 104 and NSLABs became dominant after 3 mo storage. The HS cheeses had the expected die-off of lactococci during storage to < 104 cfu/g, with this occurring faster at the highest salt level (6.4% S/M) and slower at 4.3% S/M. For LS-FF and LS-LF cheeses, lactococci remained at ~105 cfu/g throughout storage. All flavor attributes except milkfat were impacted by age (P < 0.001). Both FF and LF cheese with LS levels tended to have higher flavor attributes of sulfur, brothy, rosy, and bitter flavors. In general, LF cheese with HS level had similar flavor scores (except for milkfat flavor) to the FF cheese with LS levels. Volatiles were generally higher in FF than LF cheeses. When comparing salt levels, both LF and FF cheeses had higher concentrations of phenyl and furanone compounds known to be sources of rosy and burnt off flavors. Thus, development of undesirable flavor attributes in LF cheese was not just a function of its lower S/M content but fat content also played a role in sensory perception of flavorants.