SALAD OILS. Olive Oil. The oil supplied by the fruit of the olive tree has been used as a food by man since the earliest times. Grown originally in oriental countries, its cultivation and use have extended through Mediterranean countries to South America, and it is now grown to a considerable extent in the United States, notably in California and Arizona. About 50% of the fleshy part of the olive fruit is oil. The best grades of oil are prepared from fruit picked by hand just before maturity. These are crushed and the oil removed by gentle pressure, the first run being called "Virgin" oil or Sublime. This is generally characterized by a distinct greenish tinge of color due to the chlorophyll which is associated with the oil in the plant cells. Genuine oil may, however, lack this characteristic and may be pale or even deep yellow. Admixtures of peanut, sesame, poppy seed, corn and cottonseed oils with olive oil are much less common than formerly, although blending of inferior grades; i. e., oil obtained from repressings of the olive pulp, with higher grades is practiced to some extent in Europe. Cottonseed Oil. A keen competitor of olive oil for table use is the refined oil of the cottonseed. Although produced in countries of Europe, Asia and South America, it is essentially an industry of the United States, where methods of refining lead those of other countries. The oil is unfit for use until it has been refined, which process includes deodorizing, decolorizing and "chilling," the latter step removing the high-melting fatty constituent (stearin), which would cause the oil to "cloud" in cold climates. Corn Oil. In the process of making starch and glucose from maize or Indian corn the germ of the seed is removed. This germ contains about 15% of oil and yields the corn oil now appearing in our market. It is golden yellow in color and has a pleasant odor and taste. A sample of corn oil examined in this laboratory1 was found to be mixed with other oils, chiefly cottonseed oil. Thus early has this product been dignified and commercially flattered by adulteration. Peanut Oil. Next in importance is peanut oil, of which there is an increasing production in the United States. Like cottonseed 1 Connecticut Food & Drug Report, 1905, p. 121. oil it must be refined before it is marketable as a food oil. The refined oil has a distinct nutty flavor which commends itself to some tastes. Other Oils. Oils of the poppy-seed, rape, sesame and sunflower are not used alone to any extent in this country, but some of them may occur in admixture with the oils described above, either as adulterants or in legally marked compounds. The commercial value of the oils described is in about the following order: olive, peanut, corn, cottonseed, the values of the others being intermediate between peanut and corn oils.1 SUMMARY OF THE RESULTS OF OUR INSPECTIONS OF THESE PRODUCTS. Between 500 and 600 samples of olive oil have been examined in this laboratory since 1897, chiefly represented by six inspections. The percentage of total adulteration decreased from a maximum of 40% found in 1900, to 13.7% in 1909. It has been found that this product, put up in sealed containers, is freer from adulteration than that purchased in bulk from druggists, although the quality of druggists' goods has shown improvement. The general improvement is due in part to more truthful labeling practiced since 1905. The following tabulation2, representing 448 samples, illustrates this point. No figures are given subsequent to 1909, because no representative number of samples has been examined in any one year. TABLE I.-SUMMARY OF INSPECTIONS OF OLIVE OIL. The adulterations found in these inspections were cottonseed, sesame and peanut oils. Such admixtures, as we have noted above, do not constitute a menace to health, and, if properly labelled, would not constitute an infringement of law. Products sold under the name of "Salad Oil" our examinations have shown to consist wholly or in part of cottonseed oil. Such products are legally labelled; they do not purport to be any single oil and are sold under a distinctive name. Our experience has been, however, that they are often sold upon request for olive oil. No oil other than olive should be sold as "sweet oil." COOKING FATS. The fats chiefly used by our grandmothers for culinary purposes were the rendered fats of hogs or beef, known respectively as lard or beef suet. To-day the housewife has a large array of shortening compounds at her disposal. These nearly always appear under trade names but may contain both the animal fats mentioned combined with a vegetable oil, such as cottonseed oil, or they may be entirely of vegetable origin. Other oils mentioned in the preceding section also occur in these compounds; any of them are adaptable to such use. Our examination of some of the products in this group indicates their essential constituents to be as follows: Cotosuet2, cottonseed oil and beef fat; Cottolene3, cottonseed oil and beef fat; Korno", corn oil, cottonseed oil and a harder fat like stearin; Waverly shortening, beef stearin and cottonseed oil; Crisco, hardened vegetable oil, probably cottonseed; Vegetole, vegetable product containing cottonseed oil; Kuxit, vegetable product having the character of cocoanut fat; Wesson oil, cottonseed oil; Mazola, corn oil. A sample of Lard oil, said to have been used for deep frying, was found to contain about half its weight of mineral oil. This mixture is unique for food purposes but common as a lubricant. Recent analyses of some of these fats are given in Table II. 1 U. S. Food Inspection Decision No. 139; Conn. Rules & Regulations No. 43. 2 Connecticut Food Report 1896, p. 23. 3 Connecticut Food Report 1896, p. 23, 1900, p. 145. • Connecticut Food Report 1906, p. 122. 5 Connecticut Food Report 1909, p. 278. • Connecticut Food Report 1900, p. 148. No. Brand. TABLE II-ANALYSES OF COOKING FATS. % % % % % 99.94 0.06 59.5 1.04 Red 8164 Wesson Oilo.06 The analyses show that the samples contain only traces of moisture and are practically all fat. The percentage of free fatty acid is very low. These are the substances prominently concerned in the changes which result in rancidity. A rancid fat or oil is one in which a part of the fat has been decomposed, by enzyme action it is believed, into free fatty acids and glycerine. The action of light and air upon these fatty acids produces the substances of disagreeable taste and odor associated with rancidity. An excess of free fatty acids does not necessarily indicate rancidity, but the conditions are favorable for rancidity to occur. Edible fats and oils should be kept in securely closed containers protected from sunlight. Oils are more likely to become rancid than are solid fats. It is claimed as one of the advantages of hydrogenation that fats so treated remain wholesome for long periods. Particular attention, with respect to the presence of animal fats, has been given to those products claiming to be of purely vegetable origin. In none of them have we found evidence of cholesterol, a characteristic constituent of animal fats. The following appear to be pure vegetable products, as claimed: Wesson oil; Mazola; Vegetole; Crisco; Kuxit. There are few precise physical or chemical data by which to decide the desirability of one fat over another for culinary use. The housewife learns and decides by her experience which to use, judging by the results obtained. One thing she avoids, however, is the use of "smoky" fats for deep frying. The reason for this is that such a fat or oil "smokes" and gives off disagreeable vapors, which will be absorbed by the food, before the desired cooking temperature is obtained. A desirable fat for deep frying, then, should have a sufficiently high burning point or smoke test. Blunt and Feeney1 have determined this for a number of common cooking fats and their results are given here as of interest. The temperatures given indicate the degree of heat acquired by the fat or oil at the time it begins to give off visible fumes or vapors. The degrees have been converted to the ordinary Fahrenheit scale. The recognized temperature for deep frying is 350°-400° F. It is apparent, then, that those fats decomposing below that temperature are not well suited to this particular purpose. BUTTER AND ITS SUBSTITUTES. Butter. A typical butter contains about 15% of water and 85% of solids, of which 82.5% is milk fat and 2.5% other milk constituents and salt. Renovated Butter. Renovated butter is made by melting genuine butter and separating the curd and water-soluble constituents of the original product. The fat so obtained is rechurned with milk or cream, or both, and no other substances added except salt. Like butter, it must contain 82.5% of milk fat. The object of this treatment is to save butter which has become rancid or fallen off from prime quality. Oleomargarine is a product which varies as to proportionality of ingredients and, to some extent, as to character of ingredients, but generally it consists of oleo oil, neutral lard, butter, milk, cream and salt. Vegetable oils, such as cottonseed oil, may be used in the mixture. 1 Jour. of Home Economics, 7, p. 535, 1915. |