Phenolic maturity

Although a high concentration of anthocyanins in the skins is necessary to obtain a deep-colored wine, it is not the only condition. The cells must also be sufficiently decayed to make these molecules easily extractable by non-aggressive technology. At phenolic maturity, grapes have both... 

Table 6.16. Evolution of the phenolic maturity of Cabernet Sauvignon grapes from different vineyards in 1993 (Glories, 1994, unpnbhshed)...

The potential dissolution of skin pigment varies, especially according to maturity level. Phenolic maturity corresponds to a maximum accumulation of phenolic compounds in the berry. Cellular maturity is defined with respect to the level of cell wall degradation (Volume 2, Sections 6.5.3 6.5.4). Extraction of phenolic compounds increases with this degradation level (Amrani Joutei, 1993). Augustin (1986) defined the anthocyanin extraction coefficient (Ae) as follows ... 

The organoleptical quality of tannins is directly related to maturation conditions. Enologists have defined this quality in terms of good tannins and bad tannins. The chemical understanding of these phenolic compounds has made it possible to make a better choice of winemaking techniques that optimize the quality of various kinds of grapes. A perfect state of phenolic maturity not only supposes a maximum tannin concentration it also corresponds to soft, non-aggressive, non-bitter tannins. 

Pandjaitan N, Howard L R, Morelock and Gil MI (2005), Antioxidant capacity and phenolic content of spinach as affected by genetics and maturation , J Agric Food Chem, 53, 8618-8623. 

Fresh peppers are excellent sources of vitamins A and C, as well as neutral and acidic phenolic compounds (Howard and others 2000). Levels of these can vary by genotype and maturity and are influenced by growing conditions and processing (Mejia and others 1988 Howard and others 1994 Lee and others 1995 Daood and others 1996 Simmone and others 1997 Osuna-Garcia and others 1998 Markus and others 1999 Howard and others 2000). Peppers have been reported to be rich in the provitamin A carotenoids (3-carotene, a-carotene, and (3-cryptoxanthin (Minguez-Mosquera and Hornero-Mendez 1994 Markus and others 1999), as well as xanthophylls (Davies and others 1970 Markus and others 1999). Bell peppers have been shown to exert low antioxidant activity (Al-Saikhan and others 1995 Cao and others 1996 Vinson and others 1998) or may even act as pro-oxidants (Gazzani and others 1998). 

Burda S, Oleszek W and Lee CY. 1990. Phenolic compounds and their changes in apples during maturation... 

Prior RL, Cao G, Martin A, Sofic E, McEwen J, OBrien C, Lischner N, Ehlenfeldt M, Kalt W, Krewer G and Mainland CM. 1998. Antioxidant capacity as influenced by total phenolic and anthocyanidin content, maturity, and variety of Vaccinium species. J Agric Food chem. 46 2686-2693. 

Virgin olive oil contains considerable amounts of simple phenols that have a great effect on the stability/sensory and nutritional characteristics of the product. Some of the most representative are hydroxytyrosol (3,4-dihydroxyphenylethanol) and tyrosol (4-hydroxyphenylethanol) however, phenolic compounds are removed when the oil is refined (Tovar and others 2001). The phenolic content of virgin olive oil is influenced by the variety, location, degree of ripeness, and type of oil extraction procedure used, and that is why hydroxytyrosol can be considered as an indicator of maturation for olives (Esti and others 1998). Hydroxytyrosol concentrations are correlated with the stability of the oil, whereas those of tyrosol are not (Visioli and Galli 1998). 

Buta JG and Spaulding DW. 1997. Endogenous levels of phenolics in tomato fruit during growth and maturation. J Plant Growth Regul 16(1) 43—46. 

A similar effect was observed in other fruits and vegetables, where UV-C treated strawberries showed a higher increment of phenols and PAL activity 12 hours after treatment than unirradiated (control)(Pan and others 2004), which could be the reason for the increment in total phenol constituents (Lancaster and others 2000). UV-C and UV-B caused a two- and threefold increase in content of resveratrol (a grape phenol constituent). Thus, mature Napoleon grapes that had been irradiated with UV-C light can provide up to 3 mg of resveratrol per serving (Cantos and others 2001). Therefore, UV-C treatments clearly cause a benefit effect, increasing total phenol content, which can be mainly attributed to the increment of PAL activity. 

Even adults can still develop olfactory preferences that contravene those acquired before sexual maturity. Female laboratory mice imprinted by the odor of one mouse strain will prefer this odor even more if they are exposed to males of this strain as adults. However, if they are exposed to males of a different strain when sexually mature, their original odor preference will be reversed (Albonetti and D Udine, 1986). Naturally occurring sex or body odors may assume their sexual significance after association with sexual activity male mice were aroused by a perfume that they had experienced earlier on scented females they had interacted with (Nyby etal., 1978). Practitioners have known that adult mammals can acquire responses after exposure to certain animals. For instance, bulls of the Asian elephant that had been housed near African elephant bulls respond to temporal gland secretion and its three components phenol, 4-methylphenol, and (E)-farnesol from the latter species. Asian bulls thathad not been associated with African bulls did not respond (Rasmussen, 1988). 

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. 

L.) was also found, and was readily distinguishable by a brittleness of the culm which appeared only after maturity of the plant. This mutant had a lower cellulose content, and this difference was assumed to be related to the brittleness of the culm (24). Significant differences were also found in the extractability of the lignin fractions and associated phenolic acids (25-26), suggesting that lignin formation was also affected. 

Tehtonen M. 1983. Gas-liquid chromatographic determination of volatile phenols in matured distilled alcoholic beverages. 66(1) 62-70. 

Ozone stimulates the synthesis of anthocyanins 2, caffeoyl derivatives ( ), and total phenols ( ) in plant foliage. It induces necrotic lesions and localized discolored areas of yellow, red or brown on foliage of plants of many species. The size and number of lesions and the intensity of color are related to plant cultivar, maturity of foliage, cultural conditions, concentration of ozone and duration of time after exposure. 

Slimestad, R. and Hostettmann, K., Characterization of phenolic constituents from juvenile and mature needles of Norway spruce by means of high performance liquid chromatography-mass spectrometry, Phytochem. Anal, 7, 42, 1996. 

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