Content of apples and pears

Kevers, C Pincemail, J.I. Tabart, J. Defraigne, J. Dommes, J. 2011. Influence of cultivar, harvest time, storage conditions, and peeling on the antioxidant capacity and phenolic and ascorbic acid contents of apples and pears. J. Agric. Food Chem. 59 6165 6171. 

Pears (Pyrus communis) were cultivated by the Phoenicians and later by the Romans. There are now in excess of 500 named varieties worldwide. The total phenolic content of some cultivars of pears has been shown to be between 1235 and 2500 mg/kg in the peel and 28-81 mg/kg in the flesh (Galvis-Sdnchez etal. 2003). The phenolic composition of pears is very similar to that of apples containing 5-0-caffeoylquinic acid, 4-O-p-coumaroylquinic acid, procyanidins and quercetin glycosides. The main difference in the phenolic content of apples and pears is the presence of hydroquinone glucoside (arbutin) (Figure 7.24) in pears and the hydroxychalcones in apples (Spanos and Wrolstad 1992). The average... 

As a result of structural similarities, MCP docks on to receptor proteins for ethylene, causing it to lose activity. The texture and color of apples and pears (sensitive varieties) do not change through months of cool storage. The sugar content also remains constant while the acid content increases. Gaseous MCP adsorbed on dextran is used for the treatment of fruit. The MCP is liberated by the addition of water. The concentrations applied are in the range 300-1000 ppb. 

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