Oranges, their peel

The two enantiomers of limonene (shown in the margin) smell quite differently. The S-isomer is present in the cones of spruce trees and has a turpentine-like odor the P-isomer gives oranges their characteristic fragrance. P-Limonene is a by-product of the juice industry and is the major constituent of citrus peel oil. Every year, more than 110 million pounds of the oil are made in the United States alone. Draw the respective products of the hydrogenation of both double bonds in (R)- and (S)-limonene. Are these products isomers, identical, chiral, achiral, or optically active/ inactive ... 

Another group of natural flavoring ingredients comprises those obtained by extraction from certain plant products such as vanilla beans, Hcotice root, St. John s bread, orange and lemon peel, coffee, tea, kola nuts, catechu, cherry, elm bark, cocoa nibs, and gentian root. These products are used in the form of alcohohc infusions or tinctures, as concentrations in alcohol, or alcohol—water extractions termed fluid or soHd extracts. Official methods for their preparation and specifications for all products used in pharmaceuticals are described (54,55). There are many flavor extracts for food use for which no official standards exist the properties of these are solely based on suitabiUty for commercial appHcations (56). 

The method was then applied to extracts of orange peel but neither benomyl or thiophanate methyl were recovered as the parent compounds due to their well-known conversion to carbendazim during the extraction process - this is an effect that is not encountered when analysing standards. 

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. 

EM Gaydou, T Berahia, JC Wallet, JP Bianchini. Gas chromatography of some polymethoxylated flavones and their determination in orange peel oils. J Chromatogr 549 440-445, 1991. 

Nearly 3/4 of all vitamin C in an orange and 5/6 in a grapefruit is found in the peel (56b however, citrus juices and their products provide a major portion of the vitamin C in the American diet. Considerable variations in vitamin C content can be found in different citrus products due to such factors as varietys, maturity and cultural practices of the fruit (57J from which the products originate and to the processing practices and storage conditions of these products before they reach the consumer. 

Isoenzymes. Multiple forms of citrus PE were reported by Evans and McHale (AO) and Versteeg et al. (Al). PE was purified from West Indian limes and Navel oranges by fractionation of the whole fruit extracts with (NH. SO (AO-65%), adsorption and elution from Sephadex G-75 columns (AO). The PE active fractions were combined and concentrated before separation into two active PEs on the basis of their elution volume from a DEAE Sephadex A-50 column. Orange PEI (OPEI) and lime PEI (LPEI) had the same elution volume also OPEII and LPEII had the same elution volume. A higher concentration of NaCl was required at all pH values for optimum activity of OPEI and LPEI than of OPEII and LPEII. When the component parts of oranges were separately analyzed chromatographi-cally with DEAE-Sephadex A-50, OPEI was detected only in the peel, whereas OPEII was identified in juice sacs and section walls (AO). 

The glycoside hesperidin is a naturally occurring component of juice from oranges, tangerines and many of their hybrids. Under certain conditions of pH and fruit variety it precipitates as a scale or coating in the evaporators. When this scale becomes thick or heavy, small portions peel off and become noticeable as small white or yellow flakes in the finished product. This compound will not go back into solution and since these particles tend to settle rapidly, their presence in the reconstituted juice can be quickly detected. 

John and Kate were visiting the Great Barrier Reef for the first time. When their boat arrived at the reef they decided to go snorkelling straight away so they could see what the reef was really like. Kate was not as strong a swimmer as John and got tired. She found a place on the reef where she could stand on the coral and have a rest. John was a strong swimmer and he found a place where there were many different types of coral. He very carefully touched some to see if they were as different as they looked. After a while both Kate and John went back to the boat for lunch. They threw their orange peels into the ocean. 

The biggest market for essential oils is for perfumes, and, as might be expected, prices for these oils reflect their rarity. Recently, worldwide production of orange oil was 1500 tons and it sold for 0.75 per lb, while 400 tons of clove oil sold for 14.00 per lb, and 10 tons of jasmine oil sold for 2000 per lb. These three oils represent the most common extractive processes orange oil is obtained by expression (squeezing) of the peel in presses clove oil is obtained by steam distillation, as will be performed in this experiment and jasmine oil is obtained by extraction of the flower petals using ethanol. 

Fig. 2 shows a 2D representation of icosahedral Ceo. in which the 32 faces are numbered according to their order in this orange peel scheme. Note in particular that each face after the first borders its immediate predecessor, so that the peel comes off the orange in a single continuous spiral. In fact the entire Hiickel theory adjacency matrix for the structure can be reconstructed from the order of the penta-... 

Also, open your mind to other fruit seeds that I have enjoyed over many years for their crunch and nutrients—especially protein, essential minerals, omega fatty acids, and fiber apple, grapefruit, orange, watermelon, and pear. I eat all their seeds and even some of the edible pith and peel, each a great source of dietary fiber ... 

As a result of their sour and bitter taste, the fmits are rarely consumed. Mostly, they are cultivated for the production of peel oil. In Spain the fruit is additionally also used for producing bitter orange marmalade. Just like green mandarin oil and bergamot oil, this oil, therefore, constitutes a rather expensive citrus product, as it is not possible to distribute costs between oil and juice. 

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