Fruit maturation

Linalol is a tertiary alcohol of the formula Cj HjgO, which, with its acetic ester (and traces of other esters) forms the basis of the perfume,of bergamot and lavender oils. By dehydration linalol is converted into terpenes of which the principal are limonene and dipentene, and by esterification into its acetic ester. The examination of the essential oil at different periods of the development of the bergamot fruit has led Charabot and Laloue to the following conclusions. As the fruit matures the essential oil undergoes the following modifications —... 

Each fruit has specific quantities and ratio of pectin, hemicelluloses and cellulose. These polysaccharides are important concerning enzymes activities required to produce juices and concentrates. Moreover, even if molecular weight and methylation degree of the pectin are specific for each fruit, during the fruit maturation, endogenous pectinases depolymerases and esterase are changing the pectin characteristics This broad variability of raw material makes difficult the standardisation of fruits processing. 

Rodrigo, M. J., B. Alquezar et al. (2006). Cloning and characterization of two 9-cw-epoxycarotenoid dioxygenase genes, differentially regulated during fruit maturation and under stress conditions, from orange (Citrus sinensis L. Osbeck). J. Exp. Bot. 57(3) 633-643. 

Boag, T.S., G.I. Johnson, M. Izard, C. Murray, and K.C. Fitzsimmons. 1990. Physiological responses of mangoes cv. Kensington Pride to gamma irradiation treatment as affected by fruit maturity and ripeness. Ann. Appl. Biol. 116 177-187. 

Ethylene coordinates the expression of genes responsible for enhanced respiratory metabolism, chlorophyll degradation, carotenoid synthesis, conversion of starch to sugars, increased activity of cell wall-degrading enzymes, aroma volatile production, and so on. All these events stimulate a series of biochemical, physiological, and structural changes making fruits mature and attractive to the consumer. 

Although most consumers appreciate the fieriness of chile, capsaicinoids are not perceived through odor or taste receptors but through the nociceptive pain receptors described earlier. The compounds in chile fruit that create the flavor and aroma are produced in the fruit wall. Buttery et al. [90] generated vacuum steam distilled oil from green bell pepper macerate, with well over 40 peaks on subsequent GC/MS analysis. Of these peaks, the major flavor compound associated with bell pepper aroma was 2-methoxy-3-isobutylpyrazine (Fig. 8.1). They also reported several monoterpenoids in abundance, limonene, trans- 3-ocimene, and linalool as well as other aliphatic aldehydes and ketones. The flavor composition of dried red bell pepper powder (sweet paprika) extracted with ether identified 44 key peaks by GC/MS [91]. In these dried samples the key compounds were P-ionone and several furanones. The post-harvest processing and the different fruit maturities as well as possible varietal differences are all causes for the different aromatic profiles. 

Schemske DW, Bradshaw HD (1999) Pollinator preference and the evolution of floral traits in monkeyflowers (Mimulus). Proc Natl Acad Sci USA 96 11910-11915 Wang HC, Huang XM, Hu GB, Yang Z, Huang HB (2005) A comparative study of chlorophyll loss and its related mechanism during fruit maturation in the pericarp of fast- and slow-degreening litchi pericarp. Sci Hortic 106 247-257...

Koundouras, S. Marinos, V. Gkoulioti, A. Kotseridis, Y. van Leeuwen, C. Influence of Vineyard Location and Vine Water Status on Fruit Maturation of Nonirrigated Cv. Agiorgitiko (Vitis vinijera L.). Effects on Wine Phenolic and Aroma Components. J. Agric. Food Chem. 2006, 54, 5077-5086. 

Fruit maturity has a major impact on peel oil composition. Terpenes are almost exclusively present in the oil from unripe fruit. As fruit mature, concentrations of aliphatic aldehydes and oxygen-containing terpenes and sesquiterpenes increase [30]. For example, nootkatone and a-selinenone were not detected in the peel oils from fully developed immature fruit, but the oil from ripe fruits contained up to 0.15% of these oxygenated sesquiterpenes. 

Although it appears probable that there is no overall loss of wall polymers, except, perhaps, in the period just preceding full fruit-maturity, and that wall growth is continuous during cell expansion, there is almost certainly a turnover of wall polysaccharides, and the making and breaking of bonds to facilitate wall expansion during the maturation of fruits. The subject of the possible mechanism by which this wall expansion occurs is discussed in the Section that follows. 

Table VII. Development of Anthocyanins and Tannins as Fruit Matures...

The malic acid relationship between cold press and hot press musts conformed to the experimental observations on maturing fruit. As the fruit matured, the malic acid content decreased. The malic acid content of hot press Concord must was nearly one-third less than that of cold press Concord must. 

The tolerance limitation of fruit for irradiation establishes the maximum acceptable dose. If this dose controls decay organisms, the use of irradiation for a particular fruit may appear promising. Response to irradiation may be influenced by fruit maturity, variety, pre- and postharvest temperatures, handling, and extent of fungus growth. Climacteric fruits irradiated prior to the normal rapid increase in respiration usually show an immediate increase in respiration and the production of ethylene. These fruits are frequently retarded in ripening. 

Jawaheer et al. [12] Fruits (maturity and quality) Glucose oxidase, mutarotase, invertase/ pectin matrix and covered with a cellulose acetate (CA) membrane Screen-printed rhodinised carbon electrodes/ +350mV vs. Ag/AgCl ... 

The decrease of ascorbic acid with fruit maturity is illus-... 

Chalcones have been proposed (48) as a precursor that is enzymatically cyclized to form flavanone glycosides. The enzyme responsible for this stereospecific ring closure disappears or is inactivated as the fruit matures (5). However, no chalcones have been isolated from citrus. Therefore, if chalcones are a part of the metabolic pathway that leads to the formation of flavanone glycosides they probably exist as short lived, unstable intermediates. It appears unlikely that these compounds play a significant role in mitigating bitterness at their natural levels. 

Effects of Fruit Maturity, Rootstocks and Horticultural Variables... 

Figure 6. Effect of fruit maturity on (A) fruit size (B) weight of naringin per fruit and (C) the % of naringin in each fruit (1)...

---