Physiological and biochemical changes in asian pears (Pyrus pyrifolia L.) during ethylene induced ripening

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dc.contributor.advisorNirmaljit Kaur
dc.contributor.authorMukherjee, Purba
dc.date.accessioned2023-12-29T16:52:23Z
dc.date.available2023-12-29T16:52:23Z
dc.date.issued2023
dc.description.abstractThe present study entitled, “To study the effect of ethylene induced ripening on biochemical and physiological changes in Asian pears (Pyrus pyrifolia L.)” was carried out at Fruit Research Farm, Department of Fruit Science and Laboratories of Department of Botany, PAU, Ludhiana with the objective to decipher the optimum stage of harvest and role of ethylene on metabolic changes during fruit ripening in pear cultivars. For this, fruits of pear cultivar Patharnakh (PyruspyrifoliaBurm.F. Nakai), Punjab Beauty (Pyruspyrifolia× Pyruscommunis), Yali (PyrusbretschneideriRehd.) and Nijisseiki (Pyruspyrifolia) were examined during the fruiting season of 2022-2023. The fruit firmness, its total soluble solids, titratable acidity, flavonoid content and total sugar analysis revealed that with storage interval, the fruit firmness, titratable acidity and flavonoids declined in all cultivars; and among these, ethrel treatment reduced the firmness of fruits, titratable acidity and flavonoid content. However, total soluble solids and soluble sugars exhibited a surge from 0-5 days and declined thereafter and the ethylene treatment increased their level. The pectin, lignin and cellulose content & the cell wall degrading enzymes pectin methylesterase (PME), polygalacturanase (PG) and cellulase were analysed in the peel and pulp separately. The pectin and cellulose content declined with storage in both peel and pulp, whereas lignins increased with storage. The ethylene treatment declined the pectin and cellulose in both peel and pulp; however lignin content increased in peel as well as in pulp with ethrel. The PME showed a surge from 0-10 days and declined thereafter in peel and pulp with increase in storage duration, but in pulp another increase after 10 days storage was observed. However, the ethylene treatment increased the activity of all these enzymes. The activity of sorbitol dehydrogenase, sorbitol oxidase and acid invertase was assessed in the fruits; in all pear cultivars the activity of these sugar metabolizing enzymes declined with storage interval as well as with ethylene treatment. The MDA content increased with advance in storage duration from 0 days to 15 days and ethylene increased MDA content at all the days of storage in all pear cultivars assessed. Among all the four pear cultivars major degradation of fruit pericarp was observed in cultivar Punjab Beauty (Semi-soft pear) with increasing storage days and after ethrel treatment, whereas the cultivar Patharnakh (Hard pear) was observed to reach a more palatable texture on storage and ethrel treatment induced uniform ripening in them. The fruits of cultivars Nijisseiki, and Yali (Soft pears) did not deteriorate with storage as well as with ethrel treatment. Moreover, cell wall degrading enzymes were highest in Punjab Beauty, followed by Yali and nijisseiki and least activity was recorded in Patharnakh. Hence, it may be concluded that the pear cultivars viz., Patharnakh, Yali and Nijisseikki can be stored for ten days at 20°C and 70 % RH for uniform ripening. The semi soft pear cultivar Punjab Beauty had very high activity of cell wall degrading enzymes (unlike the soft pears) so it is suggested that this cultivar attains edible maturity by five days.
dc.identifier.citationMukherjee, Purba (2023). Physiological and biochemical changes in asian pears (Pyrus pyrifolia L.) during ethylene induced ripening (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810205086
dc.keywordsCellulose
dc.keywordsCultivars
dc.keywordsEthrel
dc.keywordsFirmness
dc.keywordsPear
dc.keywordsPectin
dc.keywordsPolygalactouranase
dc.language.isoEnglish
dc.pages81
dc.publisherPunjab Agricultural University
dc.research.problemPhysiological and biochemical changes in asian pears (Pyrus pyrifolia L.) during ethylene induced ripening
dc.subBotany
dc.themePhysiological and biochemical changes in asian pears (Pyrus pyrifolia L.) during ethylene induced ripening
dc.these.typeM.Sc
dc.titlePhysiological and biochemical changes in asian pears (Pyrus pyrifolia L.) during ethylene induced ripening
dc.typeThesis
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