ABSTRACT
Food quality, in a broad sense, means satisfying the expectation of the consumer in terms of a series of attributes, such as color, presence or absence of certain avor compounds, texture features, etc. Food quality related issues within the food industry are normally the responsibility of chemists, since the general subject of undesirable changes in the quality of food products has been traditionally related to alterations in chemical structure. The rst thing a food technologist should do, regardless of whether he/she is a chemist or not, is to relate quality changes to chemical and physical processes taking place in the food. There are several key reactions of different sorts known to have effects on food quality, and they can be summarized as follows:
Chemical reactions: these are mainly due to oxidation or Maillard-type • reactions. Microbial reactions: microorganisms can grow in foods, and this can be • desirable as in fermentation, or undesirable when causing spoilage or health risk in the case of pathogens. Biochemical reactions: many foods contain endogenous enzymes that can • potentially catalyze reactions leading to quality loss, although in some fermentation processes enzymes can be utilized to actually improve quality. Physical reactions: many foods are heterogeneous and contain particles, • which are normally unstable and can coalesce, aggregate, and in turn sediment, leading to quality loss. Some changes in texture can also be considered as physical reactions, although the underlying mechanism causing such changes may be of a chemical nature.
