Gourmet oils

Extraction can be carried out in several ways, including cold-pressing at temperatures not exceeding 45°C, pressing at higher temperatures, and/or solvent extraction. Solvent extraction is not favored for high-quality gourmet oils. Supercritical fluid extraction with carbon dioxide is an acceptable possibility, but there is no evidence that this technique is widely used for this purpose. A further possibility is to use enzymes to break down cell walls followed by extraction under the mildest possible conditions. 

Grapeseed (Vitis vinifem). These seeds produce variable levels of oil (6-20%), now available as a gourmet oil and for which Codex values have been reported. The oil is rich in linoleic acid (60-76%) and contains palmitic (6-8%), stearic (3-6%), and oleic acids (12-25%). In common with other oils rich in linoleic, it is reported to have a benehcial effect on the skin (79). Moret et al. (111) have described the effect of processing on the content of polycyclic aromatic hydrocarbons in this oil. 

Macadamia (Macadonia integrifolia, M. tetraphylla). The nuts are used as a snack food. They are rich in oil (60-70%), which is used in cosmetics and is available as a gourmet oil. It is characterized by its high level of monoene acids [total 80%, 16 1 16-23%, 18 1 55-65%, 20 1 l-3%] and is a convenient source of the... 

Passionfruit (Passiflora edulis). This popular fruit contains about 20% of oil in its seed and is available as a gourmet oil for use in speciality foods and salad dressings. It is a linoleic-rich (65-75%) but also contains palmitic (8-12%) and oleic acids (13-20%). Its high level of linoleic acid makes the oil good for skin care (157). 

Walnut (Juglans regia). Walnut oil is an unsaturated oil containing both linoleic (50-60%) and linolenic acids (13-15%) and rich in tocopherols ( 1500 mg/kg of oil). It is used as a gourmet oil in Japan, France, and other countries. A recent paper gives the detailed composition (fatty acids, triacylglycerols sterols, and tocopherols) of oil extracted with hexane and with supercritical carbon dioxide (171). 

These can be, for example, special gourmet oils (almond, apricot, avocado, grape seed, hazelnut, and walnut) or oils used for pharmaceutical and cosmetic applications (corn germ, wheat germ, evening primrose, and borage). If the deoiled residual can also be used for food or cosmetic applications, the economy of the process increases substantially. 

A steady growth in the consumption of cooking and salad oils is evident from the USDA Economic Research Service Oil Crops Situation and Outlook Reports for domestic consumption of salad and cooking oils in the United States. The consumption data by source oil is summarized in Table 25 (25, 33). Deodorized cooking and salad oils are principally prepared from soybean, cottonseed, com, canola, sunflower, and peanut oils. Olive oil is technically a cooking oil and is considered a gourmet product by many due to its distinctive flavor and odor, which would be destroyed by deodorization, considered mandatory for the other liquid oils. 

Most gourmet foods are prepared by a batch process (actually in a batch reactor). Some of the most difficult gourmet foods to prepare are Louisiana specialities, owing to the delicate balance between spices (hotness) and subtle flavors that must be achieved. In preparing Creole and Cajim food, certain flavors are released only by cooking some of the ingredients in hot oil for a period of time. 

Antoun, N. and Tsimidou, M. (1997) Gourmet olive oils stability and consumer acceptability studies. 

Olive oil of good quality needs no refining. The oil is highly esteemed by the gourmet. It is used chiefly in salad dressings, as a cooking oil, and for canning sardines. 

Data from a study to determine the allergenicity of gourmet nut oils indicate a wide variability in IgE binding from pooled serum to various brands and types... 

Teuber SS, Brown RL, Haapenen LAD. Allergenicity of gourmet nut oils processed by different methods. J Allergy Clin Immunol 1997 99 502-507. 

---