Bananas compounds

At present, eight different phases are known in banana compounds dependent on particular in-plane packing symmetry and they usually labelled as Bi, B2, -Bg, etc., counted from the isotropic phase [44]. Among them the B2 phase is especially interesting, because it has low viscosity and can easily be switched by an electric field with rather short switching times [45]. In fact, the B2 phase is basically a conglomerate of chiral and achiral antiferroelectric structures SmCAPA and SmCAPA mixed with some percentage of the two ferroelectric structures. 

Gomola, K. Guo, L. Gorecka, E. Pociecha, D. Mieczkowski, J. Ishikawa, K. Take-zoe, H. First symmetrical banana compounds exhibiting SihAPr mesophase and unique transition between two orthogonal polar phases. Chem. Commun. 2009, 6592. 

Vasoactive and Psychoactive Amines and Alkaloids Most compounds produciag hypertensive episodes are classified as amines and are found ia greatest coaceatratioa ia banana, plantain, tomato, avocado, piaeapple, broad beans, and various cheeses. Amines that are vasoactive iaclude dopamine [31-61-6], CgH N02 tyramine (11) histamine [31-43-6], tryptamine [61-34-1], C2QH22N2 noradrenaline [31-41-2], CgH NO and... 

Esters are among the most widespread of all naturally occurring compounds. Many simple esters are pleasant-smelling liquids that are responsible for the fragrant odors of fruits and flowers. For example, methyl butanoate is found in pineapple oil, and isopentyl acetate is a constituent of banana oil. The ester linkage is also present in animal fats and in many biologically important molecules. 

Ethene is used to make a host of organic compounds it is also the starting material for the preparation of polyethylene (Chapter 23). Since it is a plant hormone, ethene finds application in agriculture. It is used to ripen fruit that has been picked green to avoid spoilage in shipping. Exposure to ethene at very low concentrations produces the colors we associate with ripe bananas and oranges. 

This situation changed dramatically in 1996 with the discovery of strong electro-optic (EO) activity in smectics composed of bent-core, bowshaped, or banana-shaped achiral molecules.4 Since then, the banana-phases exhibited by such compounds have been shown to possess a rich supermolecular stereochemistry, with examples of both macroscopic racemates and conglomerates represented. Indeed, the chiral banana phases formed from achiral or racemic compounds represent the first known bulk fluid conglomerates, identified 150 years after the discovery of their organic crystalline counterparts by Pasteur. A brief introduction to LCs as supermolecular self-assemblies, and in particular SmC ferroelectric and SmCA antiferroelectric LCs, followed by a snapshot of the rapidly evolving banana-phase stereochemistry story, is presented here. 

Banana (Musa sapientum L.) is one of the most common tropical fruits, and one of Central America s most important crops. It is grown in all tropical regions and is one of the oldest known fruits [45]. From a consumer perspective, bananas are nutritious with a pleasant flavour and are widely consumed throughout the world [57]. Esters predominate in the volatile fraction of banana (Fig. 8.2). Acetates are present in high concentrations in the fruit and generally possess a low threshold. Isopentyl acetate and isobutyl acetate are known as the two most important impact compounds of banana aroma. Alcohols are the second most important group of volatiles in banana extracts. 3-Methyl-1-butanol, 2-pentanol, 2-methyl-1-propanol, hexanol, and linalool are the alcohols present in higher concentrations in the fresh fruit [45]. 

Aroma compounds of fresh banana from different countries (Martinique, Canary Islands, and Cote d Ivoire) were examined using the same extraction technique. As expected, differences in aroma composition were detected in the fruits of different origins. Isoamyl alcohol, isoamyl acetate, butyl acetate, and elemicine were detected by olfactometric analyses as characteristics of banana odour [7]. 

Fig. 8.2 Esters as character-impact compounds 4 isobutyl acetate in passion frml 5 isopentyl acetate in banana 6 ethyl butanoate in cupuacu 7 ethyl (32)-hexenoate and 8 ethyl-3-(methylthio)propanoate in pineapple...

Esters also constitute a group of important flavour compounds. They are the main aroma components found in fruits (apples, pears,. ..). For example, bananas contain 12-18 ppm acetates. The price of the pure flavour compounds, when isolated from fruit, can range between 10,000 and 100,000 US /kg In the past, research has been carried out by our group about the microbial production of fruity esters by the yeast Hansenula mrakii and the fungus Geotrichum penicillatum [10]. A fermentation was developed whereby fusel oil was continuously converted into a mixture of 3-methylbutyl acetate (isoamyl acetate) and 2-methylbutyl acetate, the character impact compounds of banana flavour. 

Most compounds producing hypertensive episodes are classified as amines and arc found in greatest concentration in banana, plantain, tomato, avocado, pineapple, broad beans, and various cheeses. Amines that are... 

Serotonin, a tryptamine, and related compounds have been found in the skins of bananas. 

Toluene as well as the other industrial chemicals occur primarily in apples, oranges and orange juice, bananas, and raisins. It is assumed that the occurrence of benzene, ethylbenzene, toluene, and xylene compounds in these fruit products may be associated with the inactive portion of pesticide formulations or is the result of contacting process equipment. The most frequent occurrence of styrene is in strawberries. This occurrence would be consistent with the ubiquitous plastic wrap or baskets associated with packaging strawberries. 

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