Factors affecting the quality of low-fat cheeses
Ibanez Alfaro, Rodrigo Ignacio
University College Cork
Low-fat cheeses are associated with defects in appearance, texture and flavour. This thesis aimed to evaluate factors affecting the quality of low fat cheeses based on optical properties, use of fat replacers and controlling the lactose to casein ratio. We studied the effect of low and high temperatures on the properties of Cheddar cheeses varying in fat content. Low-fat cheeses were more translucent than full-fat. During heating cheeses developed similar levels of opaqueness, independent of the fat content, due to protein-protein interactions. This was reversed when cheeses were cooled. Translucency and rheology were studied in low-fat Mozzarella cheese at high temperatures for different holding times. Increasing temperature and holding times reduced translucency. Excessive heat treatments led to slight increase in translucency. Cheese appearance was affected by heat-induced colloidal calcium phosphate. Rheological properties of cheeses were also affected by the formation of heat-induced calcium phosphate structures. The effects of levels of titanium dioxide, annatto and homogenisation pressure on the properties of reduced-fat Cheddar cheese were evaluated. Titanium dioxide led to cheeses with reduced translucency and an opposite trend was observed in cheeses made with annatto. Homogenisation of cheesemilk led to an increase in whiteness. CIELAB data were correlated with Kubelka-Munk analysis, except in homogenisation treatment. Supplementing cheesemilks with amidated-, high-methoxy- and lowmethoxy pectins were investigated in the properties of reduced-fat Cheddar cheese. Increased moisture content and reduced insoluble calcium in cheeses made with amidated- and low-methoxy pectins led to improved texture and melting. Using ultrafiltration in milk to reduce the lactose to casein ratio in low- and reduced-fat Gouda cheeses was proposed as an alternative method to control acid development. Cheeses made with lactose standardization had higher pH, and lower levels of lactic acid and insoluble calcium than cheeses made using traditional methods, leading to softer texture and improved melting. Sensory panelist found that cheeses made with lactose standardization were less acidic. The findings of this thesis provide a better understanding of the optical properties of cheese and propose different approaches to improve the properties of low-fat cheeses.
Cheese , Cheese rheology , Cheese translucency , Cheese texture , Cheese quality , Fat replacers , Milk ultrafiltration for cheese manufacture , Lactose to casein ratio
Ibanez Alfaro, R. I. 2016. Factors affecting the quality of low-fat cheeses. PhD Thesis, University College Cork.