Flavouring reduced fat high fibre cheese products with enzyme modified cheeses (EMCs) Nessa Noronha, Denis Cronin, Dolores O’Riordan * , Michael O’Sullivan School of Agriculture, Food Science and Veterinary Medicine, College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland article info Article history: Received 19 July 2007 Received in revised form 28 January 2008 Accepted 4 March 2008 Keywords: Imitation cheese Enzyme modified cheese Hydrolysis SPME/GC Sensory Low-fat abstract Medium (13%) and low (2%) fat imitation cheeses (pH 6 or 5.5) were flavoured with 5% w/w EMC contain- ing 16%, 28% or 47% total free fatty acids (low to high levels of hydrolysis, respectively) and were exam- ined by a sensory panel. Aroma active short-chain free fatty acids were monitored using gas chromatographic techniques. Regardless of cheese pH or EMC composition, panellists ranked all med- ium-fat cheeses similarly. Low-fat cheeses flavoured (pH 6 or 5.5) with low or medium lipolysis EMC were described as ‘well-balanced’ and ‘cheesy’ and were significantly more preferred to cheeses contain- ing high hydrolysis EMCs. Low-fat cheeses were least preferred of all cheeses because of ‘very intense’ bursts of off-flavours. Lower pH cheeses were softer and less melting. Higher fat levels in imitation cheese modulated a greater retention of fat-based flavour compounds and improved their release during con- sumption more than did lower fat levels. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction With better understanding by consumers of the link between diet and health, there is increasing pressure on the food industry to facilitate a reduction in the amount of fat and sugar and an in- crease the amount of fibre consumed by the population (COMA, 1991). Food manufacturers have responded by introducing, to the market, a number of low-fat and high fibre food products. How- ever, it is well established that reducing the fat content of foods modifies the pattern of flavour release in the mouth on chewing, and significantly impairs the perception of this key sensory attri- bute (Taylor & Linforth, 1996). Enzyme-modified cheeses (EMCs) are concentrated cheese fla- vours produced enzymatically from dairy substrates and are de- signed to provide a concentrated source of cheese flavour. Most EMCs are produced from cheese pastes made from immature cheese (West, 1996). The production of EMCs has increased, in part due to the inclusion of EMCs in zero and low-fat foods, replacing the flavour of full-fat cheese in such products (Freund, 1995). Previous work from this research group indicated that the flavour of imitation cheese could be improved by the inclusion of EMCs with medium levels (28% total free fatty acids) of hydrolysis. Our studies showed that the levels of butanoic acid, a strongly aromatic short-chain fatty acid (SCFA), were fundamental in determining the intensity and acceptability of flavoured imita- tion cheese products (Noronha, Cronin, O’Riordan, & O’Sullivan, 2008). It has been proposed that fat in natural cheese provides a fat– water–protein interface for flavour forming reactions to occur (Collins, McSweeney, & Wilkinson, 2003). In addition, fat acts as a solvent for fat-soluble flavour compounds, helping to modulate their retention in cheese (Olson & Johnson, 1990; Wijesundera & Drury, 1999). One of the main objectives of this study was to attempt to pro- duce acceptably flavoured high fibre, reduced and low-fat imita- tion cheese products. Resistant starch was used to replace the fat component of imitation cheese, as recent work from this labora- tory has shown that reduced and low-fat imitation cheeses with acceptable mouthfeel and texture could be produced when resis- tant starch was used to substitute for the fat (Noronha, O’Riordan, & O’Sullivan, 2007). However, these fat-reduced cheeses lacked fla- vour and it was thought that the incorporation of EMCs might im- prove the flavour of such products, especially since EMCs are used regularly in the industry to confer cheese flavour on a number of processed foods, including cheese sauces and pies. The strategy proposed for the present study was to examine the influence of fat (13% or 2%) and moisture levels (52% or 60%) on the flavour and textural properties of imitation cheeses containing EMCs of different levels of lipolysis. Previous work from this re- search group (Noronha et al., 2008) suggested that the pH of the cheese base influenced flavour perception in imitation cheeses fla- voured with EMCs. Therefore, another objective of this study was to examine the influence of pH on flavour intensity and acceptance, 0308-8146/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2008.03.011 * Corresponding author. Tel.: +353 1 7167016; fax: +353 1 7161147. E-mail address: dolores.oriordan@ucd.ie (D. O’Riordan). Food Chemistry 110 (2008) 973–978 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem