Apple, varieties

In a study comparing organic and conventional apples (variety Golden Delicious) from a range of commercial orchards it was found that reproducible differences between apples from organic and conventional systems can be detected (Fig. 16.6). Additionally, the vitality index produced based on the picture forming method was found to be correlated with the technical standard index based on chemical quality tests and the sensory test results (Fig. 16.7, left) (Weibel et al., 2004a). 

Wojdylo A, Oszmianski J and Laskowski P. 2008. Polyphenolic compounds and antioxidant activity of new and old apple varieties. J Agric Food Chem 56(15) 6520-6530. 

The examination was performed with the apple variety Jonagold. Apple pieces weighting 0.3-0.5 g without skin were homogenized in a Potter-type glass homogenizer and then centrifuged. Before examination, the supernatant was diluted 1 10 with double distilled water. PCL measurements were performed with 2 pL of the diluted supernatant. Apple juice contains mainly vitamin C and caroti-noids as principal ACW components. 

Flavonoids have also been analysed in the peel and pulp of different apple varieties by RP-HPLC. The varieties Golden, Red Delicious, Granny Smith and Reineta Green were inluded in the experiments. Methanol containing 1 per cent 2,6-di-/m-bu(yl-4-mc(hylphcnol... 

A. Escarpa and M.C. Gonzalez, High performance liquid chromatography with diode array detection for the determination of phenolic compounds in peel and pulp from different apple varieties. J. Chromatogr.A 823 (1998) 331-337. 

Vrhovsek, U. et al., Quantitation of polyphenols in different apple varieties, J. Agric. Food Chem., 52, 6532, 2004. 

Rudnitskaya, A., Kirsanov, D., begin. A., Beullens, K., bammertyn, J., Nicolai, B. M., and Irudayaraj, J. (2006b). Analysis of apples varieties—Comparison of electronic tongue with different analytical techniques. Sens. Actuators B 116(1-2), 23-28. 

However, in the case of apples and many other fruits the (S)-enantiomer of ethyl 2-methylbutanoate, the impact flavour compound of apples, was identified with high enantiomeric purity, irrespective of the apple variety investigated and was unaffected by processing conditions (e.g. distillation, concentrating) or storage of apple juices. 

Developing fruits are rich sources of cytokinins, which are found in tissues where rapid cell-divisions are occurring, and are considered to play an important role in the regulation of cell division in fruit.397,424 Letham424 concluded that shape of the apple at maturity probably depends upon the balance between gibberellins and cytokinins in the immature fruit, and that apple varieties differ in their response to these compounds. 

Dichlorophenpxy) acetic acid-14C is metabolized by plant tissue to inactive, water-soluble substances, some of which regenerate the parent acid on hydrolysis. The rate of metabolism differs with different species, but is usually low in comparison with the indole or naphthalene auxins. One of the earlier studies described a single major metabolite in corn, wheat, peas, and tomatoes,121 the identity of which is still uncertain. In another study of differences between species which were susceptible and those which were resistant to the herbicide, the resistant red currant metabolized 50% of the carboxyl-labeled and 20% of the methylene-labeled (2,4 dichlorophenoxy)acetic acid to 14COi in seven days, whereas the susceptible black currant altered122 only 2%. Similar effects were found with apple varieties. Strawberry and lilac decarboxylated the herbicide readily however, 16 other species, of various susceptibilities to herbicide, were unable to decarboxylate the acid to any significant extent. In both varieties of currant, 5 to 10% of the herbicide was converted into water-soluble derivatives of the parent acid, and 10 to 30% was bound in the leaf tissue in an unextractable form. 

Lapsley, K.G., Escher, F.E., and Hoehn, E. 1992. The cellular structure of selected apple varieties. Food Structure 11 339-349. 

For phenolics in fruit by-products such as apple seed, peel, cortex, and pomace, an HPLC method was also utilized. Apple waste is considered a potential source of specialty chemicals (58,62), and its quantitative polyphenol profile may be useful in apple cultivars for classification and identification. Chlorogenic acid and coumaroylquinic acids and phloridzin are known to be major phenolics in apple juice (53). However, in contrast to apple polyphenolics, HPLC with a 70% aqueous acetone extract of apple seeds showed that phloridzin alone accounts for ca. 75% of the total apple seed polyphenolics (62). Besides phloridzin, 13 other phenolics were identified by gradient HPLC/PDA on LiChrospher 100 RP-18 from apple seed (62). The HPLC technique was also able to provide polyphenol profiles in the peel and cortex of the apple to be used to characterize apple cultivars by multivariate statistical techniques (63). Phenolic compounds in the epidermis zone, parenchyma zone, core zone, and seeds of French cider apple varieties are also determined by HPLC (56). Three successive solvent extractions (hexane, methanol, aqueous acetone), binary HPLC gradient using (a) aqueous acetic acid, 2.5%, v/v, and (b) acetonitrile fol-... 

E Delage, G Bohuon, A Baron, JF Drilleau. High performace liquid chromatography of the phenolic compounds in the juice of some French cider apple varieties. J Chromatogr 555 125-136, 1991,... 

S Guyot, N Marnet, D Laraba, P Sanoner, JF Drilleau. Reversed-phase HPLC following thiolysis for quantitative estimation and characterization of the four main classes of phenolic compounds in different tissue zones of a French cider apple variety (Malus domestica Var. Kermerrien). J Agric Food Chem 46 1698-1705, 1998. 

Table 2.2. Heat requirements of different apple varieties. ...

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