Hmm...
Tottahan se on että
lyhyet menevät jossain määrin porttilaskimoon (ja vähän muuallekin itseasiassa
) mutta olen pitänyt käytännön rasvojen osalta määrää hiukan "marginaalisena" .. muutan kantaani jos on aihetta (siis tuon marginaalisuuden suuruuden osalta)... katsellaanpas hiukan... ännenkos hudtkitaan..
Ainakin yksi viite joka nimenomaan piti olla se joka kertoo rasvojen "imeytymisestä" on tällainen: Mitä tästä voimme päätellä?
http://www.jbc.org/cgi/reprint/199/1/415
(vuodelta 1952 ja tehty rotilla. )
mutta katsellaas asiaa lissää..
Että tällasta ainetta: *naur*
LAURIC ACID
PRODUCT IDENTIFICATION
CAS NO. 143-07-7
EINECS NO. 205-582-1
FORMULA CH3(CH2)10COOH
MOL WT. 200.32
H.S. CODE 2915.90
TOXICITY Oral rat LD50: 12 gm/kg
SYNONYMS n-Dodecanoic acid; Dodecylic acid; Dodecoic acid;
Laurostearic acid; Vulvic acid; 1-Undecanecarboxylic acid; Duodecylic acid;
PHYSICAL STATE white solid
MELTING POINT 43 - 44 C
SPECIFIC GRAVITY 0.883
SOLUBILITY IN WATER insoluble
Rubber & Latex, Plastics, Greases & Lubricants, Food Additives, Pharmaceuticals, Cosmetics & Toiletries
------------------------
täältä kun sattui sopivasti löytyyn linkeistäni (en ota mitään kantaa luotettavuuteen tämäntapasten sivujen osalta)
http://www.cyberlipid.org/fa/acid0001.htm#1
Solubility in water at 20°C (in grams acid per liter)
Carbon number Solubility
2 ,,,,,,,,,,,,,,,,,,,,,infinite
4 ,,,,,,,,,,,,,,,,,,,,,infinite
6 ,,,,,,,,,,,,,,,,,,,,,9.7
8 ,,,,,,,,,,,,,,,,,,,,,0.7
10 ,,,,,,,,,,,,,,,,,,,0.15
12 .............0.055
14 ,,,,,,,,,,,,,,,,,,,,0.02
16 ,,,,,,,,,,,,,,,,,,,,0.007
18 ,,,,,,,,,,,,,,,,,,,,0.003
Up to 6 (or 4) carbon atoms, organic acids are considered "short-chain organic acids", they have substantial solubility in water. Furthermore, they do not behave physiologically like other fatty acids since they are more rapidly digested and absorbed in the intestinal tract and have unique properties in regulating sodium and water absorption through the mucosal epithelium. Biochemically, they are more closely related to carbohydrates than to fats.
From 8 (or 6) to 10 carbon atoms, fatty acids are said to have a medium chain. Physiological studies have shown that ingestion of triglycerides containing these medium-chain fatty acids may result, as for short-chain fatty acids, in increased energy expenditure via faster satiety. Thus, they facilitate weight control when included in the diet as a replacement for long-chain triglycerides (St-Onge MP et al., J Nutr 2002, 132, 329).
Fatty acids which have 14 (or 12) and more carbon atoms are considered as long-chain fatty acids.
Fatty acids with 4 to 12 carbon atoms are found mainly in milk fats (mainly butyric acid in cow and decanoic acid in sheep) but those with 10 and 12 carbon atoms are found also in certain seed oils such as coconut and other kernel fats of the palm family.
Butyric acid (4:0) is the lowest member of the acetic acid series found in natural fats. It occurs (2 to 4%) as a component of milk fats. It gives a rancid odor to butter when triglycerides are hydrolyzed and is present in fermentation products of carbohydrates. This fatty acid has peculiar physiological properties in causing growth arrest and apoptosis in various cell types (Urbano A et al., Leukemia 1998, 12, 930). It was tested in the therapy of solid tumors or leukemia (Kasukabe T et al., Br J Cancer 1997, 75, 850).
Valeric acid (5:0) has been identified in petroleum distillates and in oxidation products of oils and fats and fermentation of carbohydrates. It has a putrid odor.
Caproic acid (6:0) occurs in milk fats to the extent of about 2%. It was first isolated from butter in 1816 by Chevreul. It has a characteristic odor of goats, hence its name (from the Latin caper, goat).
Caprylic acid (8:0) is widely distributed in animal and vegetable fats but rarely exceeding 8% of the total fatty acids. It occurs to an extent of 1 to 4% in milk fats, and 6 to 8% in coconut and palm oils.
Pelargonic acid (9:0) is the first example of the occurrence of an odd-numbered carbon fatty acid in natural products. It occurs in secretion of sebaceous glands and in essential oil of Pelargonium roseum from which it derives its name. It is also a primary product of oxidative fission of oleic acid.
Capric acid (10:0) occurs as a minor component in the same fats that contain caprylic acid but also in the head oil of the sperm whale, and in wool and hair fats. It is a major constituent of certain seed oils (50% in elm and 37% in California bay tree)
Lauric acid (12:0) is one of the three most widely distributed saturated fatty acids found in nature (14:0, 16:0, and 18:0). It occurs extensively in Lauraceae seeds (Laurus nobilis) where it was discovered (Marsson T Ann 1842, 41, 329). It is dominant in cinnamon oil (80-90%), coconut oil (40-60%) and is found also in Cuphea species (Umbelliferae) whose production was initiated in Germany. The recent uses of lauric acid are in the manufacture of soaps, shampoos and other surface active agents, including special lubricants. Lauric acid as monoglyceride is known to the pharmaceutical industry for its good antimicrobial properties. It may play a role in combating lipid-coated RNA and DNA viruses.
Myristic acid (14:0) is present in major amounts in seeds of the family Myristicaceae (nutmeg oil - or oil of mace - from Myristica fragrans contains about 60-70% of trimyristin) where it was first discovered (Playfair L Ann 1841, 37, 152). Nutmeg is found in Moluccas and spice islands of Indonesia. Coconut and palmkernel oils are also convenient sources of C8-C14 fatty acids which are isolated in a pure form by distillation. It is also present in milk fats (8-12%) and in the head oil of the sperm whale (15%).
Palmitic acid (16:0) is the commonest saturated fatty acids in plant and animal lipids.
It was purified first by Chevreul in his researches on butter and tallow, but was first surely characterized by Fremy E (Ann 1840, 36, 44), who prepared it in pure form from palm oil, from which he named it. Despite its wide distribution, it is generally not present in fats in very large proportions. It usually forms less than 5% of the total fatty acids, sometimes as much as 10% in common vegetal oils (peanut, soybean, corn, coconut) and in marine-animal oils. Lard, tallow, cocoa butter palm oil contain 25 to 40% of this component.
Stearic acid (18:0) was described by Chevreul (1823) in the course of his researches on fats. It is the highest molecular weight saturated fatty acid occurring abundantly in fats and oils. It occurs in small quantities in seed and marine oils. Milk fats (5-15%), lard (10%), tallow (15-30%), cocoa and shea butters ((30-35%) are the richest sources of stearic acid. It is the principal constituent of hydrogenated fats and oils (about 90%).
The longer chains are less frequent, they can be found in uncommon seed oils (C20-24 in Leguminoseae and Sapindaceae), in waxes (C24-30) and in some sphingolipids (C20-24). These fatty acids (from C24 to C28) appear to be produced by microalgae and it was estimated that diatoms contribute from 30 to 80% of these components in sandy sediments (Volkman JK et al., Org Geochem 1998, 29, 1163). These long-chain fatty acids derive from higher plant waxes and are more abundant in deep than in surface sediments (Rieley G et al., Org Geochem 1991, 17, 901; Muri G et al., Org Geochem 2004, 35, 1083).
Arachidic acid occurs in appreciable quantities in groundnut oil (3%) but larger amounts are found in seeds of Sapindaceae (up to 20%). It is also found in the depot fat of some animals and in milk fats.
Behenic acid was first reported as a constituent of ben (behen) oil (seeds of Moringa oleifera) (Voelcker A Ann 1848, 64, 342). Except for the seed oils of the Crucifereae (between 0.5 and 3.4%), this fatty chain does not occur in the principal oils. Large amounts are found in hydrogenated animal and vegetal oils (8-57%).
Lignoceric acid is present at trace levels in plant oils except in groundnut oil (about 1%) and notably in a Leguminous seed oil (Adenanthera pavonina) where it may amount to about 25%. It is the principal fatty acid present in carnauba wax (30% of the normal fatty acids)
Without double bonds or other functional groups, these fatty acids are nearly chemically inert and thus can be subjected to drastic chemical conditions (temperature, oxidation).
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