In mammals, odorant binding proteins may play an important role in the transport of odors towards specific olfactory receptors on sensory neurones across the aqueous compartment of the nasal mucus. We have solved the X-ray structure of such a transport protein, bovine odorant binding protein (OBP) at 2.0 A resolution. The beta-barrel of OBP is similar to that of lipocalins, but OBP dimer association results from domain swapping, an observation unique among the lipocalins. The alpha-helix of each monomer stacks against the beta-barrel of the other monomer. Contrary to previous reports, each monomer has an internal buried cavity which could accommodate a naturally occurring molecule. Besides this cavity, an open cavity is located at the dimer interface. Data in solution suggest that this central cavity may be a binding site created by domain swapping.

Cow nasal tissue contains a protein which shows specific binding activity for ‘green’ smelling compounds such as 2‐isobutyl‐3‐methoxypyrazine. This protein has now been purified using anion‐exchange fast protein liquid chromatography. The protein has a relative molecular mass of 400000–44000, s= 3.1 ± 0.3 S, pI = 4.7 ± 0.1 with an absorbance maximum at 278 nm, and consists of two subunits with an identical relative molecular mass of 19000. It is localised in the soluble fraction of cells from the olfactory mucosa and respiratory mucosa from the middle part of the maxillary and nasal turbinates, and is absent from all other tissues tested.

To understand the concept of "total food quality" and how it has evolved, we give a brief historic outline from Pasteur to the recent rise of the globalized market. Nowadays, "total food quality" is clearly a partially objective concept in the sense that it can be defined according to scientific and technological criteria and partly subjective because consumers' judgments, mainly based on their appraisal, may equally concur in its definition. Food properties contributing to "total food quality" definition and assessment include (1) organoleptic and sensory attributes, (2) food safety, (3) nutritional value, (4) functionality, (5) service and stability, (6) wholesomeness, and (7) psychological factors. Many technological and gastronomic treatments may alter food components, e.g. fats, proteins, and vitamins (the most sensitive to physico-chemical changes in the environment), thus, negatively affecting any one of the aspects of quality in the above list. Specific analytical strategies and sensitive appliances can be utilized both to assess and protect food quality and to correctly conduct and monitor food production. Among the so-called psychological factors, however, there are some molecular aspects that are still elusive, although of enormously great interest. In fact, food can have some psycho-active effects on the consumer, thus, influencing his or her behavior during either pre-ingestive or post-ingestive phases. As studies of psycho-active substances in food seem to be opening up a new scenario in "total food quality" research, the gathering together in a single chart of all the information on the effects of food on its journey, from sight to ingestion, would seem like a good basis for a more rational and thorough discussion of the topic.

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