Dairy Industry Association of Australia

Flavour development in dairy fermentations, most notably cheeses, results from a series of (bio)chemical processes in which lactic acid bacteria (LAB) play a pivotal role. Flavour compounds in cheese arise from the action of added enzymes such as rennet, indigenous milk enzymes, enzymes originating from added primary and secondary (adjunct) starter organisms and the nonstarter bacteria (so-called NSLAB). Studies on flavour compound formation by LAB have shown that three main processes can be distinguished: conversion of lactose and citrate (carbohydrate metabolism); degradation of fat (lipolysis); and degradation of caseins (proteolysis). The diversity of cheeses in the market requires a diversity of commercial starter cultures, including the use of different species as adjunct cultures that are selected based on their flavour-related properties. In addition, specifically selected adjuncts are helpful for modulating the cheese texture, i.e. the exopolysaccharide producers. This paper will review the opportunities offered by the adjunct starter concept for modulating the cheese characteristics. These adjunct cultures provide added value to the cheese without affecting its primary cheese manufacturing process. In addition, modification of cheese and whey processing can be achieved by using selected enzymes, i.e. an Aspergillus niger carboxy-peptidase is found to accelerate the flavour development and reduce bitterness in cheese, and a novel peroxidase isolated from the mushroom Marasmius scorodonius gives reduced levels of annato-derived colour in whey without adverse side-effects on flavour and functionality of the whey.