Ketoheptose content of some tropical fruits

Abstract

Ten tropical fruits (17 varieties) were analyzed to determine their ketoheptose content. Paper chromatography and gas chromatography of the trimethylsilyl derivatives of the sugars were utilized to obtain the data. Avocado contained appreciable amounts

High-performance liquid chromatographic analysis of D-manno-heptulose, perseitol, glucose, and fructose in avocado cultivars

“…We also found more manno-heptulose in the Collinson (1.75%) than previously reported [0.7% by Simon and Kracier (1966); 0.2% by Richtmyer (1962)]. Our Florida-grown sample of the Fuerte, a major cultivar produced in California, contáined a low level of mannoheptulose (<0.1%) that fell within the values reported earlier [0.07% by Ogata et al (1972); 0.23% by Simon and Kracier (1966)]. Since manno-heptulose content decreases rapidly during ripening in many cultivars, and no standard definition of ripeness in avocados exists (Lewis, 1978), it is possible that variation in degree of ripeness for the samples tested accounts for much of the reported variation.…”

“…Avocados are the richest known natural source of the seven-carbon sugar D-manno-heptulose (Simon and Kracier, 1966), but a systematic study of the manno-heptulose content in avocados has only been carried out on a few cultivars (Simon and Kracier, 1966; Ogata et al, 1972). The related seven-carbon alcohol perseitol is also present in avocados (Richtmeyer, 1963).…”

“…Previous studies on manno-heptulose content in avocados have shown widely varying amounts depending on cultivar, on degree of ripeness, and (allegedly) on whether the fruit was attached to the tree during ripening (LaForge, 1917; Montgomery and Hudson, 1939;Davenport and Ellis, 1960;Richtmyer, 1962; Simon and Kracier, 1966;Ogata et al, 1972).…”

“…had ripened on the tree contained slightly less than a sample picked in the unripe state and then allowed to ripen. The other systematic study of manno-heptulose content in avocados was reported by Ogata et al (1972). They studied the manno-heptulose content in both pulp and peel of four avacado cultivars.…”

Pineapple and papaya

“…The difference is due to a failure to allow for invertase (EC 3.2.1.26) activity during tissue homogenization (Chan and Kwok, 1976), and which has been shown to increase IS-fold during fruit ripening (Pal and Selvaraj, 1987). Trace quantities of sedoheptulose have also been reported (Ogata et al, 1972).…”