• Korean Journal of Food Science and Technology
• /
• v.48 no.1
• /
• pp.59-65
• /
• 2016

This study was carried out to investigate the total polyphenols, antioxidant activities, and melanin synthesis inhibition of several pear cultivars (Pyruspyrifolia). The total polypenolic content of five pear cultivars was high in the unripe developmental stage. Total polyphenolic content of the Chuwhangbae cultivar extract was higher than that of other pear cultivars regardless of the developmental stage. However, the total flavonoid content did not differ between cultivars or developmental stages. The phenolic compound, arbutin has an inhibitory effect on melanogenesis. Arbutin levels in pear cultivars declined as the fruit matured. The free radical scavenging activity of the extract also decreased as the fruit ripened. In B16F10 mouse melanoma cells, most of the cultivar extracts inhibited melanin synthesis by about 50% at a $100{\mu}g{\cdot}mL^{-1}$ concentration, except in the Gamcheonbae extract until 90 days after full bloom. We have confirmed that the extract of pear cultivars have antioxidant activity and skin-whitening effects.

• Food Science and Preservation
• /
• v.16 no.6
• /
• pp.991-998
• /
• 2009

We used pears to manufacture wine, and analyzed changes in pH, acidity and ethanol and sugar content during fermentation. Pear wine with added ginger (to improve quality) did not differ from ginger-free wine in pH or acidity level. The ethanol content of pear wine was the highest (13.0%, v/v) inpear wine with 0.1% (w/v) added ginger compared to pear wine with no ginger, and sensory tests examining taste and color yielded the highest scores for pear wine with 0.2% (w/v) ginger. To assess storage stability, pear wine was treated for 30 minutes at $55^{\circ}C$, $60^{\circ}C$, $65^{\circ}C$, or $70^{\circ}C$. Unheated pear wine showed rapid changes in pH and acidity level after 30 days of storage, whereas pear wine treated for 30 minutes at $60^{\circ}C$ did not show such changes. Total organic acid levels in pear wine increased by 0.71% and 0.89% (v/v), respectively. The free sugar level in pear wine decreased from 12.05% to 3.13% (w/v). Turning to phenolic compounds, caffeic acid, catechin, and epicatechin contents in pears were 1.64, 1.40, and 0.23 mg/100mL, respectively, with diverse compositions. Caffeic acid levels in pear wine decreased sharply to 0.12 mg/100 mL upon fermentation, whereas free catechin inpear wine increased to 1.16 mg/100 mL compared with 0.28 mg/100 mL in pears. Free arbutin increased from 8.34 mg/100 mL in pears to 10.39 mg/100 mL in pear wine. The free amino acid content of pear wine was 118.5 g/100 mL, but the levels of serine, alanine, glutamic acid, and aspartic acid decreased sharply upon fermentation, with corresponding increases in tyrosine, GABA, lysine, and arginine.

• Journal of Forest and Environmental Science
• /
• v.37 no.3
• /
• pp.226-234
• /
• 2021

Two species, P. pyrifolia and P. ussuriensis, of the genus Pyrus native to Korea, are valuable genetic resources that can be used for food, dietary supplement, pharmaceutical, and cosmetics. Bioactive compounds of the plant leaves are the main components that are used for the products. Farmers had cultivated a few individuals from the wild to produce fruits or leaves for traditional remedy or tea; however, bioactive components of their leaves are not tested. We selected some trees from the natural stand that have distinct traits for the improvement program. We investigated the bioassay on the extracts' bioactive compounds and antioxidant capacity from the selected accessions and other accessions, including newly developed cultivars. The contents of the phenolic compounds and flavonoids from the leaf extracts of the selected accessions were higher than the commonly cultivated trees in both species but lower than 'Sanhyang' in P. ussuriensis. The antioxidant capacity was measured using two assay methods, DPPH and ABST. The selected cultivars also had higher inhibitory activity than common trees. The selected accession 'Cultivar 3' in P. pyrifolia had the highest radical scavenging activity than others. Although leaves of the accessions were used only in this study, all three selected individuals have the potential for cultivar in containing high bioactive compounds and antioxidant capacity.

• Korean Journal of Food Science and Technology
• /
• v.37 no.6
• /
• pp.905-911
• /
• 2005

Physical properties and compositions of dietary fiber sources (DFS) from peels of Asian pear fruit, Hosui, Niitaka and Chuwhangbae, were examined at different growth stages, young, unripe, and ripe fruits, to investigate their use as functional ingredients. Total dietary fiber (TDF) contents of DFS prepared from peels of three cultivars at three stages were high, 74.00-88.38%, with most being insoluble dietary fiber. Total phenolic compound contents of DFS were 1.64-4.46mg/g, with those of Niitaka and Chuwhangbae increasing with growth stages. Density of DFS from young fruit was significantly lower than those from unripe and ripe fruits (p<0.05), because particle size of DFS increased with growth stages within cultivars. Water-holding capacity (WHC) and oil absorption were 3.11-6.03g water/g solid and 1.98-2.57g oil/g sample, respectively. Young fruits, which showed lowest WHC value, had highest oil absorption value. Particle size of DFS had significant correlation with density, WHC, and oil absorption (p<0.05). Physical properties of DFS were mainly influenced by cellulose and uronic acid.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.4
• /
• pp.367-373
• /
• 2010

The study was established to compare fruit qualities and antioxidant compounds in 'Niitaka' pear (Pyrus pyriforia) trees grown in the organic and conventional farming systems. Fruits in the organic system appeared to have dark red color on the fruit surface. Fruit weight, soluble solids, acidity, firmness, and stone cells were not different between the farming systems. Organic fruits had a greater potassium concentration than the conventional fruits, but phosphorous, calcium, and magnesium concentrations in fruits were not different between the treatments. Peel, flesh, and juice parts in the organic fruits had greater phenolic compounds compared to the conventional fruits. Peel parts had much greater antioxidant compounds than the flesh parts, regardless of the treated-fruits. All fruits grown in the conventional and organic systems had a similar DPPH ($\alpha$, $\alpha$-diphenyl-$\beta$-picryl-hydrazyl) radical-scavenging activity in the peel, but flesh parts in organic fruits had a greater DPPH than the conventional fruits. Phenol and flavonoid compounds in the peel and flesh were positively related to the DPPH radical-scavenging activity. There were no significant differences for the nitrite scavenging activity in the peel and flesh parts between the treatments.