Tropical Fruit Flavour

Mario Roberto Marostica Jr, Glaucia Maria Pastore 

The characteristic exotic flavour of fruits from the tropics is one of the most attractive attributes to consumers. Nowadays, food industries are looking at how to use these volatiles to produce amazing new products that can accommodate this new demand. The following sections report some of the relevant research data on volatiles of some important tropical fruits. 

Guava is native to Central America. It was distributed into other parts of tropical and subtropical areas such as Asia, South Africa, Egypt, and Brazil by the early seventeenth century [49]. Some examples of impact-flavour compounds have already been identified in guava -ionone [58], terpene hydrocarbons [63], and esters [43] could be mentioned. 

Essences of pink and white fresh guava obtained by direct extraction of flesh juices with dichloromethane revealed that the total amount of Cs aldehydes, alcohols, and acids comprised 20 and 44% of the essence of fresh white and pink guavas, respectively [49]. The flavour of the Costa Rican guava has been described as sweet with strong fruity, woody-spicy, and floral notes [53]. One hundred and seventy-three volatile compounds were isolated by simultaneous steam distillation-solvent extraction. The terpenes and terpenic derivatives were found in this fruit in major concentrations and were strong contributors to tropical fruit notes (Fig. 8.1). The aliphatic esters contributed much to its typical flavour. 

Characterisation of the aromatic profile in commercial guava essence and fresh fruit puree extracted with solvent yielded a total of 51 components [29]. Commercial essence was shown to be rich in components with low molecular weight, especially alcohols, esters, and aldehydes, whereas in the fresh fruit puree terpenic hydrocarbons and 3-hydroxy-2-butanone were the most abundant components. 

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Fig. 8.1 Acyclic, monocyclic, and bicyclic terpenes contribute to tropical fruit flavours to papaya 2 A -carene to mango 3jS-caryophyllene to girava fruit...

M R. Marostica Jr G. M. Pastore, Tropical Fruit Flavour. In Flavours and Fragrances Chemistry, Bioprocessing and Sustainability R. G. Berger, Ed. Springer-Verlag Berlin, 2007 pp 189-201. 

Figure 9.17 There are powerful synergies between Sauvignon Blanc grapes and yeast strains in formation of the compounds responsible for tropical fruit flavours 4-mercapto-4-methylpentan-2-one (4MMP), 3-mercaptohexan-l-ol (3MH) and 3-mercaptohexyl acetate (3MHA). Odourless cysteine and glutathione conjugates are converted to aromatic thiols by carbon-sulfur-lyase enzymes. Alcohol acetyl transferase further modifies 3MH, converting it to the more potent 3MHA.

Franco, M. and Janzantti, N. 2005. Aroma of minor tropical fruits. Flavour and Fragrance Journal, 20(4), 358-371. 

Schreier, P., The use of HRGC-FTIR in tropical fruit flavour analysis, in Analysis of Volatiles Methods and Applications, P. Schreier, Ed., de Gruyter, Berhn, 1984, p. 269. 

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]. 

Mango is one of the most popular and best known tropical fruits [44] and possesses a very attractive and characteristic flavour. Some authors reported great differences in flavour compounds (including esters, lactones, monoterpenes, and sesquiterpenes) [14]. 

Owing to their unique and delicate flavour, species of the genus Passiflora have been the subject of intensive research on their volatile constituents [13]. The purple passion fruit (Passiflora edulis Sims) is a tropical fruit native to Brazil but is now grown in most tropical and subtropical countries [50]. Purple passion fruit is cultivated in Australia, India, Sri Lanka, New Zealand, and South Africa [48]. Yellow passion fruit (Passiflora edulis t flavicarpa) is one of the most popular and best known tropical fruits, having a floral, estery aroma with an exotic tropical sulfury note [62]. Yellow passion fruit is cultivated in Brazil, Hawaii, Fiji, and Taiwan [48]. Because of its more desirable flavour, the purple passion fruit is preferred for consumption as fresh fruit, whereas the yellow passion fruit is considered more suitable for processing [28]. 

Pineapple, one of the most popular tropical fruits in the world, has been cultivated in South America since the fifteenth century [61]. It has been very popular throughout the world for many years [16]. Native to Central America and South America, pineapples grow in several tropical countries, such as Hawaii, India, Malaysia, the Philippines, and Thailand [12]. Owing to its attractive sweet flavour, pineapple is widely consumed as fresh fruit, processed juice, canned fruit, and as an ingredient in exotic foods. The volatile constituents of pineapple have been studied for over 60 years by many researchers. More than 280 compounds have been found among volatiles of pineapples so far [60]. 

The aroma compounds from the tropical fruits described in this chapter can be very important for consumers and industry as they are exotic and extremely pleasant however, the production of these compounds by biotechnological processes should be emphasised since the extraction from the fruits is a hard task. Many tropical soils contain less nitrogen and phosphorus, have lower capacity to absorb fertilisers, and therefore have lower conventional productive capacity, but some tropical soils have been very intensively farmed and further intensification is possible in other areas. Thus, the evaluation of a sustainable agriculture in tropical regions requires a sophisticated approach including the estimation of the risk of microbial or insect infestations. As many fruits go directly to fresh markets or to immediate processing, a continuing supply of the flavour manufacturers in the future is not completely assured. 

Before 1900 Import of tropical fruits and spices Identification of some flavouring substances Synthesis of some flavouring substances... 

This tropical fruit, rich in juice and seeds, a native of South America, has a very refreshing sour sweet, juicy taste with a specific green, fmity powerful exotic fresh flavour reminiscent of pineapple. The background is spicy floral perfumistic in the direction of ylang-ylang with ciimamon. 

When the caramels are pulled and air is incorporated into the candy mass, flavourings resistant to oxidation are required. The most popular taste directions are caramel, cream, butter, coffee, cocoa, vanilla. In the case of products where dairy ingredients and sugars are used, a browning reaction (caramelization) takes place. The flavour type has to harmonize with the inherent flavour of the candy. In caramels with a fruity taste, oil-soluble fruit flavourings can be used. Flavour types such as orange, lemon, raspberry, cherry, strawberry, blackcurrant and tropical fruits are typical. 

In addition methylthio substituted carboxylic acids are still unnoticed riverine contaminants. Methylthioacetic acid ethylester is a known volatile constituent of melones, passion fruits, further tropical fruits as well as wine (e.g. Wong and Ong, 1993, Beaulieu and Grimm 2001, Jordan et al. 2002, Moreira et al. 2002). Therefore its application as flavour constituent in fragrances seemed to be possible. Further technical usage also of methylthio acetic and propionic acids are unknown. On the contrary methylthiobenzothiazol and its metabolite benzothiazole are well known riverine contaminants as the result of their usage as biocorrosion inhibitors,... 

Fruit is used in ice cream products, either as fruit pieces, or as a sauce. Fruit pieces add novelty to ice cream products and enhance the perception of healthiness. Sauces, often fruit, but also chocolate and toffee, are widely used as toppings on cone and cup products or as ripples in ice cream. They provide flavour and texture contrast as well as an attractive product appearance. A wide range of fruits is used in ice cream products, from common European fruits such as strawberry and apple, to tropical fruits such as mango and banana. 

The patients receive a dedicated low residue diet (Nutra Prep , E-Z-EM, Lake Success, NY, USA). This diet is provided in a box and supplies the patient with all the meals and drinks for the entire day before CT colonography (Fig. 4.2). This box contains powdered drinks with vanilla flavour, fruit drinks, soups, chips and nutrition bars. The diet reduces the fat intake and the faecal output. Patients are allowed to have breakfast (8 a.m.), lunch (noon) and dinner (5 p.m.). Breakfast consists of a tropical fruit juice, one vanilla drink and tea or coffee. At lunch patients drink another tropical fruit juice and vanilla drink and/or apple sauce, a soup and tea or coffee. At dinner they can have another soup and/or vanilla drink. Between the meals they can eat the chips and nutrition bars. The patients are allowed to drink as much additional water as they want to. 

Engel, K.H., J. Heidlas, R. Tressl, The flavour of tropical fruits (banana, melon, pineapple), in Food Flavours Part C The Flavour of Fruit, A.J. McLeod, Ed., Elsevier, Amsterdam, 1990, p. 195. 

Although vanillin, ethyl vanillin and sucrose are normally not considered as flavour modifiers, they nevertheless have flavour modifying properties Isolated from the leaves of Gymnema sylvestre, a tropical plant Glycoprotein from miracle fruit, the fruit of a West African shrub... 

The study of correlation between volatile compounds by instrumental analysis and sensory properties of Albarino wine from NW Spain was performed by Vilanova et al. (2010). The results of the investigation showed the compounds that most contributed to the flavour of Albarino wines in instrumental analysis were those related to fruity (ethyl esters and acetates) and floral aromas (monoterp>enes). Similar results were found in sensory analysis where the descriptors with the highest Geometric Mean were fruity and floral aromas too (citric, flowers, fruit, ripe fruit, ap>ple and tropical). Therefore, this work demonstrates that some relationship between sensory data and volatile compoimds exist to asses sensory properties in Albarino wines. 

Inga edulis (family Leguminosae Mimosoideae) Commonly known as the ice cream bean. It is indigenous to Central and South America and introduced elsewhere in the tropics, including Africa. The fruit pulp is used in flavouring desserts. The pods are eaten as vegetables. 

Averrhoa carambola (family Oxiladaceae) Originating in South-East Asia, this species is now cultivated in all tropical regions. It is commonly known as star fruit. The fruits are larger and less acidic than bilimbi, with a quince-like flavour. The good cultivars are eaten raw, sliced and used as salad but fruits are usually used in jellies, jams and drinks. 

Annona squamosa (family Annonaceae) Indigenous to America and now widely distributed throughout the tropics and subtropics. The fruits are used as a dessert the pulp, which has a pleasant texture and flavour, may be mixed with milk to form a drink or made into ice cream. The oil is extracted from seeds for making soap and the seed cake is used as manure. 

An important sulfide is methional (8-37). Methional in beer and wine is formed by the activity of microorganisms. It is partly reduced to the corresponding alcohol methionol (8-13) and reaction with acetyl-CoA yields 3-methylthiopropyl acetate (8-129), which is an important component of various fermented foods. Another ester of acetic acid 3-(methylthio)hexyl acetate is a component that posseses attractive tropical fruity notes on dilution. The less odoriferous (-)-(J )-enantiomer (8-130) is reminiscent of passion fruit, while the (-l-)-(S)-form has a more herbaceous odour. The odour thresholds of these thiols in air are 0.10 ng/1 and 0.03 ng/1, respectively. Both isomers have been found in passion fruit (Passiflora edulis, Passifloraceae), guava Psidium guajava, Myrtaceae) and aromatic white wines. Methyl-3-(methylthio)propionate, or pineapple mercaptan (8-131), has a flavour reminiscent of pineapple. S-Methylthiohexanoate (8-132) is a component of the durian fruit smell. Condensation of methional with ethanol yields (Z)-2-(methylthio)methylbut-2-enal also known as 2-ethylidenemethional (8-133), which is an important component of potato chips aroma. It also occurs in... 

Monellin is extracted from the fruit Dioscoreophyllum volkensii (syn. D. cumminsii, Menispermaceae) native to tropical African rainforests. Monellin is a sweet protein with liquorice-like flavour, which consists of two peptide chains, A and B, composed of a sequence of 45 and 50 amino acids, respectively (11.5 kDa). Under food processing conditions it is unstable and has no practical significance as a sweet substance. 

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