“grassy” or “paint-like” flavors in food ( Frankel, 1983 ). Hydrolysis of triacylgycerides yields free fatty acids. Quantifying the peroxide value, hexanal content, and free fatty acids provides insight into the amount of lipid degradation that has
hydrocarbons. Hydrolysis of triacylgycerides yields free fatty acids. The walnut harvest occurs once a year in autumn, when the nuts are mature for harvest, using a mechanical shaker. Some orchards are shaken twice to maximize yield. Walnuts are stored in
concentration, they are not taken up readily. Aldehydes as natural FA metabolites ( Drawert, 1975 ) are therefore more suitable to be applied as aroma precursors. Fig. 5. Comparison between the concentrations of total and free fatty acids of apple and strawberry
cultivar. Fig. 1. Changes in free fatty acid (FFA) content (percent oleic acid) of oils obtained from olives stored at different temperatures (4 °C, 10 °C, and room temperature) for different periods of time (1, 5, 9, 16, and 23 d). (A) ‘Barnea’, (B
was based on flame ionization detector peak areas and the internal standard hexadecane. Specific correction factors were developed from external standards and applied to the peak areas of the free fatty acids and alkanes. For all other peaks, a factor
Pollen from five cultivars of pecans [Carya illinoinensis (Wangenh.) K. Koch] was analyzed for cytoplasmic lipid classes and constituent fatty acids. Lipid classes in all cultivars included free fatty acids, triglycerides, and the phosphatide of inositol, serine, choline, glycerol, and ethanolamine. Triglycerides were the predominant class of lipids in all cultivars analyzed. Gas chromatography and mass spectral analysis were used to identify and quantify the fatty acids, which included palmitic, stearic, oleic, linoleic, and linolenic. Quantities of individual and total fatty acids varied greatly and were influenced significantly by cultivar, year, and location, as well as by interactions of main effects The percent composition of individual fatty acids was remarkably stable, despite wide variation in quantities of fatty acids. Therefore, pollen fatty acid ratios may be a valuable measure of taxonomic relationship across Carya sp. Total fatty acids varied from 2.53% to 0.25% of dry weight. Variability in stored energy in the form of lipids may affect orchard production.
highly divergent alcohol dehydrogenases of melon exhibit fruit ripening-specific expression and distinct biochemical characteristics Plant Mol. Biol. 61 675 685 Nie, L.C. Sun, J.S. Di, B. 2005 Changes in amino acid and fatty acid contents as well as
The pungency in hot peppers [Capsicum annuum (L.) var. annuum] is mostly due to two capsaicinoids, capsaicin (CAP) and dihydrocapsaicin (DC), which are amide derivatives of vanillylamine and 8-methyl-6-nonenoic acid (E) or 8-methyl-nonanoic acid (A), respectively. During our investigation of the mechanism of capsaicinoid-specific metabolism in pepper fruit, we have developed a method to extract, purify, and quantitate these fatty acids from the free fatty acid pool in placental tissue. Fresh placenta was ground using a mortar and pestle and extracted with diethyl ether. Fatty acids were methanolysed and fatty acid methyl esters were quantitated using GC with capric acid as internal standard. Capsaicinoids accumulated in the same placenta were extracted with N,N-dimethylformamide (DMF) and quantitated using HPLC. The lipid fraction had to be separated from capsaicinoids, since capsaicinoids yielded about 10% of their respective fatty acids during methanolysis. An aminopropyl column was used to separate capsaicinoids from free fatty acids. Extraction recovery for both fatty acids was greater than 70%. This procedure is being used to quantitate fatty acid precursors for capsaicinoid biosynthesis in pepper placenta. We will demonstrate use of this procedure with pepper selections varying in CAP/DC ratio to evaluate the effect of metabolic precursors on capsaicinoid metabolism.
Pollen from five cultivars (cvs.) of pecans [Carya illinoinensis (Wangenh.) K. Koch] was sampled at Brownwood and College Station, Texas, in 1991 and 1992. Samples were analyzed for cytoplasmic lipid classes and constituent fatty acids. Lipid classes in all cvs. included phosphatidyl inasitol, phosphatidyl swine, phosphatidyl choline, phosphatidyl glycerol, phosphatidyl ethanolamine, free fatty acids, and triglycerides. Triglycerides were the predominant class of lipids in all cvs. analyzed. Fatty acids, qualitated and quantitated by gas chromatographic-mass spectral analysis, included palmitie (16:0), stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) adds. Quantities of individual and total fatty acids were significantly influenced (P> 0.05) by tree age. Within a uniform age class, quantities of individual and total fatty acids varied greatly and were significantly influenced by cultivar, year, and location as well as by interactions of main effects. The percent composition of individual fatty acids was stable in relation to total fatty acids in the sample, despite wide variation in quantities of fatty acids in different samples. Total fatty acids varied from 2.53% to 0.25% of dry weight. How this large variability in stored energy levels among pollen sources may affect orchard production is discussed.
Developmental changes in total cuticle and cuticular constituents were studied with `Delicious' fruit. Total wax (0.31 mg/cm2) and total cutin (0.54 mg/cm2, including carbohydrate polymers) were low in young fruit. They increased during fruit growth and reached 1.41 and 2.47 mg/cm2 of fruit peel at harvest, respectively. During fruit ripening at 20 °C, total cutin did not change, but total wax increased rapidly and reached 2.15 mg•cm-2 at 6 weeks. The increase of cuticular wax paralleled the increase of internal ethylene in fruit. Wax was separated by column chromatograph into four portions, hydrocarbons and wax esters, free alcohols, free fatty acids, and diols. More than half of the diols was ursolic acid. During fruit development, more hydrocarbons and diols accumulated in cuticle than free fatty acids and alcohols. During fruit ripening, all of the four portions increased, coincident with the climacteric rise in ethylene, but the increase rates of free fatty acids and alcohols were higher than those of other portions. Aminoethoxyvinylglycine (AVG, 220 mg•L-1) preharvest treatment inhibited internal ethylene synthesis to below 0.5 μL•L-1 during 6 weeks at 20 °C, and also inhibited wax accumulation. Ethephon (200 mg/L) preharvest treatment increased ethylene production and accelerated wax accumulation. α-farnesene accumulation coincided with increased internal ethylene and paralleled free fatty acid and alcohol accumulation.