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Consumption of certain phenolics in the diet is considered beneficial to human health. In this study, individual phenolics were measured by diode-array HPLC at monthly intervals in the peel of Granny Smith, Lady Williams, and Crofton apple cultivars stored in air at 0 degrees C for 9 months. The concentrations of total phenolics significantly differed among the cultivars examined, with Lady Williams peel having significantly more phenolics (over 4000 microg x g(-1) peel fresh weight) than Crofton (2668 microg x g(-1) peel fresh weight) and Granny Smith, which had the lowest concentration of total phenolics (1275 microg x g(-1) peel fresh weight). There were also significant differences in individual phenolics among cultivars and during storage. Quercetin glycosides were the only flavonols identified, with quercetin rhamnoglucoside being the most abundant phenolic in the peel. Chlorogenic acid was the major cinnamic acid derivative, with high concentrations, up to 412 microg x g(-1)) peel fresh weight, in Crofton peel. A pre-storage diphenylamine (DPA) treatment had few significant effects on peel phenolic metabolism. Where differences did occur, fruit treated with DPA retained higher concentrations of total peel phenolics during storage than fruit not treated with DPA. Storage of all cultivars for up to 9 months in air at 0 degrees C induced few significant changes in the peel phenolic concentrations. This indicates that phenolic metabolism in apple peel is relatively stable, and the health benefits of phenolics in apple peel should be maintained during long-term storage.

Research into the mode of action of the essential oil of Melaleuca alternifolia (Tea tree oil) is briefly reviewed. Its mode of action is interpreted in terms of the membrane-toxicity of its monoterpenoid components and different approaches for determining cell membrane damage are discussed.

The sesquiterpenoids (+)-δ-cadinene, epicubenol and cubenol in the essential oils of the Myrtaceae are by-products of the acid-solvolysis of the sesquiterpene alcohols cubebol and epicubebol. This solvolysis can occur during leaf ageing or steam distillation. Significant proportions of these compounds can be found in many members of the Myrtaceae, most notably commercial tea tree (Melaleuca alternifolia and M. linariifolia). Copyright © 2000 John Wiley & Sons, Ltd.

The presence of terpinen-4-ol in the steam distillates from Melaleuca argentea, M. dissitiflora and M. linariifolia can be linked to high levels of (+)-sabinene and cis- and trans-sabinene hydrate in the leaf material. Incorporation of 18O into the terpinen-4-ol from steam distillates performed in H2 18O confirms the generation of the terpinen-4-yl carbocation intermediate from (+)-sabinene and cis- and trans-sabinene hydrate. This same mechanism is also operating during leaf aging.

(Z)-β-ocimene has been found to occur in amounts of 85% in foliage of Homoranthus montanus Craven and S. R. Jones and 69–71% in H. flavescens Cunn. ex. Schauer. (E)-β-ocimene also occurred in amounts of 5–9% and 2–5% respectively. The oil yield in both cases was 0.3–0.5% based on fresh leaves.

A hydrodistilled oil obtained from the leaves of Leucas milanjiana Gurke (Lamiaceae) was analysed by capillary GC and GC-MS. The leaf volatile oil contained 30 components, out of which 26 were identified. The predominant components were found to be β-cubebene (38.15%), α-pinene (19.71%), trans-caryophyllene (7.41%) and α-terpinolene (5.34%). The results are qualitatively and quantitatively at variance with data on other Leucas species and may therefore be of some chemotaxonomic significance for the genus. Copyright © 2006 John Wiley & Sons, Ltd.

Changes in the aroma volatiles, free amino acids, sugars, principal acids, and soluble minerals were studied during the development and ripening of the fruit of Cucumis melo L. Reticulatis group cv. Makdimon. Ethyl acetate was the most abundant volatile produced during the final growth stage, but ethanol was the major volatile found in immature fruit. Most of the free amino acids exhibited increases in concentration as the fruit underwent the ripening process. Sucrose, although absent in immature fruit, showed a dramatic increase during ripening to become the major carbohydrate constituent in the ripe fruit. The changes in total soluble solids during ripening showed close correlation with those found for pH, certain amino acids, and the elements sodium and potassium. Sucrose concentration has been shown to be an important fruit quality indicator, so these further correlations suggest that some of these parameters may be significant additional determinants of eating quality. Keywords: Melons; fruit develop...

Fatty acid compositions and lipid contents of five common table species of marine fish from temperate Australian waters were determined for samples taken during two seasons (four species) and three locations of markedly differing latitude (one species). Variabilities in total lipid extract and phospholipid fatty acid compositions were assessed between samples of each species, as well as between individuals of the same sample. These were then compared with data obtained for the other species analysed. The highest n3 polyunsaturated fatty acid (PUFA) content lipids were found in fish from colder waters (southern locations and spring season catches). The leaner species were found to have much more stable lipid characteristics with changes in the water temperature at sampling.

Analysis of the volatile constituents of melon by HRGC-MS has led to the identification of a number of compounds not previously reported in other varieties. These compounds include a range of thioether and several diesters derived from butane-2,3-diol and propane-1,2-diol. The properties of the thioethers esters are of considerable sensory importance and hence play a role in determining consumer preference.

This work discusses the influence of the ethylene antagonist 1-methyl-cyclopropene (1-MCP) and the timing of its application on the ripening related parameters in bananas such as ethylene, CO 2 and volatiles production, volatiles composition and skin color. The preclimacteric application of 1-MCP to banana fruit delayed the onset of the common parameters associated with ripening, namely ethylene and aroma volatiles production, respiration and skin color changes. The extent of these delays depended on the developmental stage of the fruit at application and on whether the fruit was subsequently challenged with the ethylene analogue, propylene. The application of 1-MCP to bananas continuously challenged with propylene delayed the onset of ripening and volatiles production by two days. When preclimacteric mature green bananas were allowed to naturally ripen in the absence of propylene, 1-MCP delayed the onset of ripening by nine days. Hence 1-MCP application offers a convenient means of examining the role of ethylene in ripening and offers an excellent opportunity to differentiate and clearly study the biochemical and physiological interactions occurring in ripening fruit.

Fatty acid compositions and lipid levels of five common table varieties of marine fish from temperate Australian waters were determined. Nutritionally important values were calculated and compared with those of species from similar waters in the northern hemisphere. P/S and n-3/n-6 ratios, and the levels of arachidonic (AA) and docosahexaenoic (DHA) acids in the lipids were comparable for the two, but the Australian species had lower eicosapentaenoic acid (EPA) levels. Oils from Australian fish were shown to have nutritional properties as beneficial as their northern hemisphere counterparts.

Separation, dosage et identification, par chromatographie gazeuse sur colonne capillaire et spectrometrie de masse. Tous les composes identifies sont des mono- ou sesquiterpenes, dont les pinenes, le germacrene D et le bicyclogermacrene. La maturation des fruits n'a pas d'incidence sur leurs teneurs en composes volatils