Citrus composition

Due to its alkali stability it is used in citrus compositions for soaps and detergents. 

Uses. Citronellol is one of the most widely used fragrance materials, particularly for rose notes and for floral compositions in general. As flavor material, citronellol is added for bouquetting purposes to citrus compositions. It is the starting material for numerous citronellyl esters and for hydroxydihydrocitronellol, an intermediate in the production of hydroxydihydrocitronellal. 

The literature contains considerable citrus compositional data along with many proposed methods of detecting adulterations. However, there are few general reviews on adulteration. Jorgensen... 

There is yet another important principle exemplified by the use of Hedione in Eau Sauvage. The synthesis of methyl dihydro jasmonate occurred within the context of a study of jasmin, and Hedione, in its odor, represents an aspect of the jasmin complex. The idea to use it to make better jasmin bases is obvious. Its incorporation in a herbaceous citrus composition certainly was not. Creative breakthroughs come from nonobvious uses. 

Mondello et al. (54) have developed some applications of on-line HPLC-HRGC and HPLC-HRGC/MS in the analysis of citrus essential oils. In particular, they used LC-GC to determine the enantiomeric ratios of monoterpene alcohols in lemon, mandarin, bitter orange and sweet orange oils. LC-GC/MS was used to study the composition of the most common citrus peel, citrus leaf (petitgrain) and flower (neroli) oils. The oils were separated into two fractions, i.e. mono- and sesquiterpene... 

Frozen Foods. Corrosion caused by the reaction of foods with aluminum containers is unusual if the products are handled and stored at 0°F or lower. However, the inevitable bad handling of frozen foods during commercial distribution causes undesirable thawing. In this condition, not only does the food deteriorate, but it can also attack the container. Such unwanted reactions can be effectively controlled by using coated aluminum containers. Since aluminum is highly compatible with frozen fruits and citrus juices, it has been used extensively as a liner for fiberboard composite cans, as complete aluminum cans, or as ends in combination with steel can bodies in the frozen food industry. 

Table II. Carbohydrate compositions (weight percentage) of individual oligomer peaks purified (QAE-Sephadex or HPLC ion-exchange separation, respectively) from mixtures of citrus pectin oligomers or B fruit extracts Compositions shown are for peaks whose biological activity is described in Figure 4. Uronic acid values are based on colorimetric assay. Proportions of neutral sugars were determined by GC and adjusted so that totals equal 100%. In fact, some oligomers (G7 peaks 8, 9 and 10. B extract peak 10) produced small (less than 1 % of the total integrated area), unknown peaks in the GC chromatograms.

Ultrafiltration of heterogenous colloidal suspensions such as citrus juice is complex and many factors other than molecular weight contribute to fouling and permeation. For example, low MW aroma compounds were unevenly distributed in the permeate and retentate in UF in 500 kd MWCO system (10). The authors observed that the 500 kd MWCO UF removed all suspended solids, including pectin and PE. If PE is complexed to pectate in an inactive complex, then it is conceivable that release of PE from pectin with cations will enhance permeation in UF. At optimum salt concentration, less PE activation was observed at lower pH values than at higher pH (15). In juice systems, it is difficult to separate the effect of juice particulates on PE activity. Model studies with PE extracts allows UF in the absence of large or insoluble particulates and control of composition of the ultrafilter. In... 

After the extraction of lipid and nonlipid components from the leaves of mandarin orange Citrus reticulata, the lipid fraction was further separated by PTLC to determine different lipid classes that affect the chemical deterrence of C. reticulata to the leaf cutting ecat Acromyrmex octopinosus. These lipids seem to be less attractive to the ants [81a]. The metabolism of palmitate in the peripheral nerves of normal and Trembler mice was studied, and the polar lipid fraction purified by PTLC was used to determine the fatty acid composition. It was found that the fatty acid composition of the polar fraction was abnormal, correlating with the decreased overall palmitate elongation and severely decreased synthesis of saturated long-chain fatty acids (in mutant nerves) [81b]. 

Bocco A, Guvelier ME, Richard H and Berset C. 1998. Antioxidant activity and phenolic composition of citrus peel and seed extracts. J Agric Food Chem 46 2123-2129. 

Another study employed an ODS column and different mobile phase composition for the measurement of carotenoids in orange juice. Citrus fruits were hand-squeezed and the juice was filtered. Aliquots of 5 ml of juice were extracted with ethyl acetate (3 X 50 ml) containing 0.004 per cent butyl hydroxytoluene (BHT). The organic phase was dried with 50 g of anhydrous sodium sulphate and the aqueous phase was mixed with 50 ml of mehanol and 100 ml of 1 M NaCl, extracted with 75 and 25 ml of ethyl acetate. The ethyl acetate fractions were combined, evaporated to dryness at 40°C and redissolved in the mobile phase. Extracts were analysed in an ODS column (250 X 4.6 mm i.d. particle size 5 jian). The mobile phase consisted of ACN-methanol-l,2-dichloroethane (60 35 5, v/v) containing 0.1 per cent BHT, 0.1 per cent triethylamine and 0.05 M of ammonium acetate. The column was not thermostated and the flow rate was 1 ml/min. Pigments were detected... 

Gattuso G, Barreca D, Gagiulli C, Leuzzi U, Caristi C (2007) Flavonoid composition of Citrus juices. Molecules 12 1641-1673... 

Example 1 Citrus oil or citrus root products can Indeed kill slugs if they are applied as a contact agent or act as a slug repellent. Although some patents have been issued on the use of citrus oil as a slug control agent, such control with a contact agent is difficult and the chemical compositions of citrus oil and root exudate are ill-defined. Other obstacles for commercialization of citrus oil are (1) market size is too small to justify the development cost, and (2) an effective delivery method has yet to be developed. 

A comprehensive and critical review of food flavonoid literature has led to the development of a food composition database for flavonols, flavones, procyanidins, catechins, and flava-nones. This database can now be used and continuously updated to estimate flavonoid intake of populations, to identify dietary sources of flavonoids, and to assess associations between flavonoid intake and disease. However, there is a need for better food composition data for flavones, procyanidins, and flavanones as current literature is sparse particularly for citrus fruits, fruit juices, and herbs. In addition, anthocyanin food composition data are lacking although validated methods of determination are becoming available. 

Figure 4.5. The NP composition of a typical plant extract (in this case, a citrus hybrid) as revealed by gas chromatographic analysis. The peaks on the upper trace represent the different chemicals detected by the instrument, with the peak area being a measure of the amount of any substance. Note that there are a few major NP peaks but even more very minor ones. The spikes pointing down on the lower trace are the odours detected by a human sniffer with their perceived odour name. Note the human detection of odour does not always correspond to the emergence of a major chemical peak. For example near the start of the analysis, the green or burning smell detected by the human does not correspond to any instrument detection so those chemicals are below the level of detection of the instrument. (Modified from the data of Morton M, Smoot JM, Mahattanatawee K, Grosser] and Rouseff RL, Citrus Research and Education Center, University of Florida.)...

CH3(CH2)9CH0, C11H22O, Mr 170.29, bp2Ave 1°C, df 0.8251, ng 1.4325, occurs in citrus oils. It is a colorless liquid with a flowery-waxy odor that has aspects of freshness. Undecanal is the prototype of the perfumery aldehydes and is widely used in perfume compositions for imparting an aldehydic note. ... 

CH3(CH2)iiCHO, C13H26O, Mr 198.34, i pijkPa 128 °C, df 0.8356, nf 1.4384, occurs in lemon oil and has been identified as a volatile constituent of cucumber. It is a colorless liquid having a fatty-waxy, slightly citrus-like odor. Addition of tridecanal to fragrance compositions imparts fresh nuances in the top note as well as in the dry out. 

Uses. Nerol is used in perfumery not only for the same purposes as geraniol, e.g., in rose compositions, to which it lends a particular freshness, but also in other blossom compositions. In flavor work it is used for bouquetting citrus flavors. Technical-grade nerol, often in a mixture with geraniol, is used as an intermediate in the production of citronellol and citral. 

Myrcenol is used in perfumery to obtain a lifting top note in citrus and lavender compositions. It is mainly important in the production of 4-(4-hydroxy-4-methylpentyl)-3-cyclohexenecarboxaldehyde (see p. 83). 

Uses. Because of its strong lemon odor, citral is very important for aroma compositions such as citrus flavors. In perfumery it can be used only in neutral media due to its tendency to undergo discoloration, oxidation, and polymerization. It is used as a starting material in the synthesis of ionones and methylionones, particularly /3-ionone, which is an intermediate in vitamin A synthesis. 

In aroma compositions, fatty acid esters of the acyclic terpene alcohols are used for obtaining citrus notes and for rounding off other flavor types. 

It is used in a large number of blossom fragrances. However, its use in perfumes for soap and cosmetics is limited because it causes discoloration. It is used in aroma compositions (e.g., in grape and citrus flavors). 

Oils isolated from other parts of citrus plants (blossoms and leaves) are not classified as citrus oils because the former show marked differences in composition and organoleptic properties, they are described in other sections (see Neroli Oil, and Petitgrain Oils). 

Production of Citrus Essence Oils. Distillative concentration of citrus juices yields essence oils, which separate from the aqueous phase in the receiver when the distillate condenses. The composition of essence oils is similar to that of peel oils, but the essence oils usually contain larger quantities of aliphatic ethyl esters (e.g., ethyl butyrate in orange essence oil). Thus, their aroma resembles that of a particular juice more than that of peel oils. 

The relation of the constitution of saturated petroleum fractions to their insecticidal efficiency was shown in the case of a single insect species in a previous paper (9). To extend this study the Citrus Experiment Station of the University of California, the Shell Oil Co., and the New York State Agricultural Experiment Station cooperated to include other species and to examine the insecticidal properties of various hydrocarbon compositions derived directly or indirectly from petroleum as well as synthetic hydrocarbons of known constitution. Part of the program planned for the New York Station consisted of ... 

The material aid and cooperation of the Shell Oil Co., in support of this research program is gratefully acknowledged. The authors would also like to express their appreciation to A. M. Boyce, L. A. Riehl, and other members of the staff of the Citrus Experiment Station, Riverside, Calif., for their active support and cooperation in the program. Thanks are also due to M. R. Fenske and R. W. Schiessler of the Pennsylvania State College for their advice and guidance in the preparation of the hydrocarbon compositions utilized in this work. 

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