Cheese ripening: An overview of technological strategies towards process acceleration

Abstract

Cheese is considered to be a biocomplex ecosystem colonized by a diversegroup of microorganisms provided by raw milk and starter and non-startermicroorganisms. This microflora is the major contributor to the perceivedsensory attributes in the different cheese types owing to its complex interaction with the milk components (proteins, carbohydrates, and fats) thatmainly occur in a key technological step during cheese manufacturing,known as ‘ripening’.During ripening, flavour and texture of cheese are developed. This processis governed by three main metabolic routes: (1) metabolism of residuallactose, lactate, and citrate, (2) proteolysis and amino acid (AA) catabolism,and (3) lipolysis and free fatty acid (FFA) metabolism. Cheese is a biochemically dynamic product containing up to 100 billon bacteria per gram,all of which metabolize carbohydrate, proteins, and/or lipids to create a myriad of aromatic and sapid compounds that contribute to flavour to a greater or lesser extent depending on the cheese variety. The degree and extent of these biochemical events are affected by manyfactors including the type and amount of residual coagulant, presence of starter and non-starter microorganisms, addition of exogenous enzymes, technology of manufacture (temperature/time, curd washing, curd salting and pressing, etc.), and environmental conditions during manufacturingand ripening. Many cheese varieties are essentially similar at the end of manufacturing stage in terms of chemical composition and texture; however, a number of changes occur during ripening based on ripening conditions (temperature, time, environmental) and these influence the flavourand texture of cheese, as mentioned above.Ripening is a slow process, especially for low moisture cheese varieties, and expensive in terms of controlled atmosphere storage and stocks, that is not fully predictable or controllable. Long maturation time is an economic issue in developing countries as energy supplies in these countries are either very expensive or insufficient. Cheese ripening acceleration is of major interest in the cheese industry, mainly in semi-hard and hard cheeses due to the high costs associated withlong storage periods, providing significant economic contributions toproducers such as net savings in refrigeration, labour and inventory costs,as well as increased cheese production when storage facilities are limited. In contrast, poor texture or flavour defects (bitterness, rancidity) are the maindrawbacks that may occur, resulting in a diminution in the shelf life andquality of cheese.Factors that affect mainly the process of proteolysis and lipolysis can bemanipulated with the potential view of accelerating ripening, withoutaffecting shelf life and cheese quality. In this sense, various approaches havereceived considerable attention in the literature; even though this is relatively easy to achieve it is very difficult to control.