Polenske value

For purposes of identifying natural fats and ascertaining their quality, a number of analytical tests are routinely employed. The test results of a sample of fat under assessment should fall within the range of established constants to confirm its identity. For coconut oil the usual tests are fatty acid composition, acid value/ percent free fatty acid, saponihcation value, iodine value, Reicheit-Meissl value, Polenske value, unsaponifiable matter, peroxide value/stabihty test, s.p./m.p., color, and solid fat content (see Tables 5 and 6)... 

The Reichert-MeissI value is the number of milliliters of 0.10 A sodium hydroxide required to neutralize volatile fatty acids (mainly C4 and C6) of 5.0 g of oil. Polenske value is the number of milliliters of 0.10 A sodium hydroxide required to neutralize insoluble fatty acids (mainly C8, CIO, C12) of 5.0-g oil. Typical Reichert-MeissI and Polenske values of coconut oil are 8.4 and 11.5, respectively (33). Both values are significantly high, as expected in coconut oil, which is a rich source of MCFA. 

The water-insoluble fatty acids on the filter paper are washed, dissolved in ethyl alcohol, and titrated with 0.10 A sodium hydroxide. Polenske value = B — S where B = titer of blank in mL and S = titer of insoluble fatty acids in mL. 

In respect of fatty acid composition (FAC), both CNO and PKO have about the same level of lauric acid (12 0). The main difference is that CNO has about twice as much caprylic (8 0) and capric acid (10 0) but half as much oleic acid (18 1). Before the advent of GLC it was difficult to test for adulteration or to distinguish between CNO and PKO in blends and use was made of the so-called Reichert and Polenske values, which are indicative of the short fatty acids present. These tests are highly empirical, laborious, and not very discriminating between CNO and PKO in blends with other oils. Though obsolete, they are still specified by Codex. The Reichert values for CNO and PKO are 6-8.5 and 4-7 respectively and 13-18 and 8-12 for the Polenske values. (Gunstone et al. 1994, pp. 61 and 85). 

Flash pt 445 F (230"C) ignition temp 840"F (449I°C). Surface tension (dynes/cm) at 20 , 39.0 at 80 , 35.2. Acid value <4. Sapon no. 176-187. Iodine no. (Wijs ) 81-91. Reichert-Meissl value <0.5. Polenske value <0.5. Acetyl value 144-150. Hydroxy] value 161-169. Miscible with abs ethanol, methanol, ether, chloroform, glacial acetic acid. Dissolves in its own vol of petr ether or 95% alcohol. Does not dissolve to any extent in mineral oil, unless mixed with another vegetable oil. When heated to 300" for several hours it polymerizes and becomes miscible with mineral oil. 

Pale yellow to brownish-yellow oil. Slight characteristic odor and taste. The flavor of crude soybean oil has been described as paint-like and grass-like, and is somewhat distasteful to the palate of occidentals, djf 0.9)6-0.922. Flash pt 54Acid value 0.3 -3.0. Saponification value 189-195. Iodine value 127-138. Thiocyanogen value 77-85. Diene no. 0.7. Hydroxyl value 4-8. Reichert-Meissl value 0.2-0.7. Polenske value 0,2-1.0. Miscible with abs alcohol, ether, petr ether, chloroform, carbon disulfide. 

Bland yellow oil resembling corn oil. d 0,925 0,933. njf 1.469-1 478. Acid value 6-20. Saponif value 179-190. Iodine value 115-129. Thiocyanogen value 80-85. Hydroxyl value 10-48, Reichert-Meiss] value 0.3-1.4, Polenske value 0.4-2.1. Hehner value 76-95. Miscible with chloroform. ether, benzene, petr ether. Slightly sol in ale. 

Reichert value Polenske value GLC ranges in fatty acid... 

Cocoa fat and lipids In AOAC methodologies, the composition of fat and fatty acids in cocoa fat extracts are analyzed and characterized by physicochemical methods, including refractive index, melting point, saponification value and unsaponifi-able material, iodine number, Reichert-Meissl and Polenske values. 

These adulterants may also be detected by the Polenske value. Paraffin, beef stearin and tallow may be detected by Bjorklund s test. 

The Polenske value is the number of mililiters of 0. IN aqueous alkali solution required to neutralize steam volatile water insoluble fatty acids distilled from 5g of the oil/fat under the prescribed conditions. It is a measure of the steam volatile and water insoluble fatty acids, chiefly caprylic, capric and lamic acids present in oil or fat (I.S.I. 1984f). 

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