Changes in olive properties and oil quality, oxidative stability, phenolic and chemical composition of two common Turkish varieties (Memecik and Edremit) during maturation were investigated. Olive samples were collected in their own growing region for five different harvest dates and processed to oil with a laboratory scale mill. Metabolic behaviors of these two varieties along with the maturation were different in terms of some compositional parameters. Oleic acid, triolein, b-sitosterol, oleuropein, hydroxytyrosol, and tyrosol contents of olive or olive oils fluctuated with maturation. However, changes in average weight, flesh/pit ratio, water and oil contents of the olives were observed. Phenolics such as trans cinnamic acid contents of both olive fruits decreased whereas cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside anthocyanins increased. Free fatty acids of virgin olive oils were found independent of maturity although some slight changes were determined in peroxide value, dien and trien conjugations. Some compositional parameters such as pigment concentration, tocopherols, stearic acid, linolenic acid, palmitodiolein and monounsaturated/polyunsaturated fatty acid ratio decreased while linoleic acid, dioleolinolein, palmitooleolinolein and D-5-avenasterol percentages increased with the maturation. A clear discrimination was observed with principal component analysis. The data obtained can also be considered useful for providing information to determine the ideal maturity stage.

Effects of the industrial refining process on some properties of hazelnut oilHazelnut (Corylus avellana L.) oil was chemically refined using industrial refining conditions. Crude hazelnut oil was obtained by pre-pressing-solvent extraction methods and refined by neutralization, bleaching and deodorization in industrial scale. The changes in color, free fatty acids, fatty acid composition, tocopherol and phytosterol contents were determined after each step of refining. The main color change was observed during bleaching. Fatty acid composition, mainly oleic acid (81%), did not change significantly during the process. At the end of the refining, the amounts of total tocopherol and phytosterol decreased from 51.89 to 46.67 mg/100 g and from 168.04 to 141.48 mg/100 g, respectively. The biggest losses of both tocopherols and sterols were observed after neutralization. Deodorization caused a slight decrease in the amount of sterols. a-Tocopherol (36.19 mg/100 g), b-tocopherol (9.3 mg/100 g), and gsitosterol (120.28 mg/100 g) were the predominant unsaponifiables in refined hazelnut oil.

The epoxidation of methyl linoleate was examined using transition metal complexes as catalysts. With a catalytic amount of methyltrioxorhenium (4 mol%) and pyridine, methyl linoleate was completely epoxidized by aqueous H 2 O 2 within 4 h. Longer reaction times (6 h) were needed with 1 mol% catalyst loading. Manganese tetraphenylporphyrin chloride was found to catalyze the partial epoxidation of methyl linoleate. A monoepoxidized species was obtained as the major product (63%) after 20 h.

Prickly pear fruit seeds were subjected to a range of chemical analyses during their 15 week maturation period. Seeds contained on average 71.5 g kg −1 dry matter, 61.9 g kg −1 crude oil, 9.4 g kg −1 protein, 507.4 g kg −1 crude fibre, 12.3 g kg −1 ash and 409.0 g kg −1 carbohydrate. The fatty acid composition of prickly pear seed oil consisted of 1.3-1.9 g kg −1 myristic (14:0), 132.1-156.0 g kg −1 g kg −1 arachidic (20:0) and 2.1-3.0 g kg −1 behenic (22:0) acids, which is comparable with that of corn oil. No statistical difference in seed weight ratio was determined during the maturation period, whereas changes in the saturated fatty acids of the seed oil were observed. From this study it can be concluded that the seeds of prickly pear are suitable as animal feed.

Phenolic compound distribution of Turkish olive cultivars and their matching olive oils together with the influence of growing region were investigated. One hundred and one samples of olives from 18 cultivars were collected during two crop years from west, south and south-east regions of Turkey. The olives were processed to oils and both olive and olive oil samples were evaluated for their phenolic compound distribution. The results have shown that main phenolics of Turkish olives were tyrosol, oleuropein, p-coumaric acid, verbascoside, luteolin 7-O-glucoside, rutin, trans cinnamic acid, luteolin, apigenin, cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside. Oleuropein and trans cinnamic acid were present in higher amounts among all phenolics. Principal component analyses showed that the growing region did not have drastic effect on phenolic profile of olives. The major phenolic compounds of olive oils were tyrosol, syringic acid, p-coumaric acid, luteolin-7-O-glucoside, trans cinnamic acid, luteolin and apigenin. Luteolin is a predominant phenolic compound in almost all oil samples. Total phenol concentrations of Southeast Anatolian oils were found to be lower than those of the other regions.Abbreviations: PCA, principal component analysis; VOO, virgin olive oil Eur.