• Food Science and Preservation
• /
• v.16 no.1
• /
• pp.82-86
• /
• 2009

By analysis of pyruvic acid and sugar levels in bulbs, leaf sheaths, and leaves, and with regard to phyllotaxis, it was shown that the lower portion of each plant component had the greatest pyruvic acid content, the upper portion less, and the middle portion the lowest. When bulb scales were examined, pyruvic acid content was lowest in the second bulb scale from the papery scale. Pyruvic acid level increased toward the inner portion of the bulb. Pyruvic acid levels in leaf sheaths and leaves were greater than those in the bulb during the early stages of bulb growth. However, at harvest, the pyruvic acid content of bulbs increased slightly, whereas those of leaf sheaths and leaves decreased markedly. Tissue sugar contents were similar at the beginning of bulb growth. However, bulb sugar content increased greatly as the bulb grew, and sugar contents of leaf sheaths and leaves decreased. With respect to phyllotaxis, outer older leaves had the lowest total sugar and pyruvic acid contents. Young leaves showed a tendency to have less pyruvic acid and sugar compared with mature leaves.

• Korean Journal of Food Science and Technology
• /
• v.29 no.6
• /
• pp.1151-1157
• /
• 1997

The chemical identities of purified polysaccharide, methylan, were analyzed by various chemical methods. The polysaccharide contained 79%(w/w) sugar, 6% protein, and 16% organic acids such as uronic acid, pyruvic acid, and acetic acid. With proceeding fermentation, the acids content in methylan increased from 10% at 34 hr to 17% at 72 hr, and the viscosity of methylan in the same concentration also increased. The correlation between viscosity and acid content in methylan was studied using chemically or biologically modified methylan. Methylan with a high content of pyruvic acid exhibited a high apparent and an intrinsic ·viscosity. When the pyruvic acid content of methylan with the same content of uronic acid was increased 1%, apparent viscosity and intrinsic viscosity increased 290 cp and 6 dL/g, respectively. Methylan with a high content of uronic acid exhibited a high apparent and an intrinsic viscosity. When the uronic acid content of methylan with the same content of pyruvic acid was increased 1%, apparent viscosity and intrinsic viscosity increased 85 cp and 1.5 dL/g, respectively. It was found that the increased viscosity of methylan resulted from the increased content of organic acids in methylan, and pyruvic acid was more an important factor contributed to the increase of methylan viscosity than uronic acid.

• Journal of Bio-Environment Control
• /
• v.17 no.4
• /
• pp.266-272
• /
• 2008

The aim of this study was to investigate the effect of supplemental lighting with different lighting intensity during growth on the sugar and pyruvic acid content of onion bulbs. As the result of comparison with growth, the content of pyruvic acid and sugar at harvest, supplemental lightening condition showed better growth, lower pyruvic acid content and higher sugar content than control. As to the growth at harvest according to lightening condition, 'Josaeng-ssundeobol' showed better growth as the lightening increased and 'Damrojunggab' had no difference above $12{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PAR. 'Josaeng-ssundeobol' contained much more content of pyruvic acid and sugar than 'Damrojunggab'. 'Josaeng-ssundeobol' had the lowest pyruvic acid content in $24{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PAR and 'Damrojunggab' had no difference above the $12{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PAR. The sugar content of 'Josaeng-ssundeobol' had no big difference above $18{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PAR and that of 'Damrojunggab' had no big difference above $12{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PAR. Desirable indicator to select individuals for the onion breeding is to select individuals that has low pyruvic acid content and high sweetness. Therefore, it will be possible to produce sweet onion conditioned on light supplement over $18{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PAR in 'Josaeng-ssundeobol' and over $12{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PAR in 'Damrojunggab'.

• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.377-381
• /
• 2010

This study was carried out to access the stauts of pyruvic acid and sugars in onion bulbs during storage at room temperature. Pyruvic acid content remained in a steady state until 3 months of storage. However the pyruvic acid content gradually increased as the onions started to root, and rapidly increased after sprouting. There was no difference in dry matter contents during storage.e. Sucrose content increased as storage duration extended, and then gradually decreased right after the onions started to sprout. Fructose content gradually decreased after 45 days of storage, and remained in a steady state after sprouting. Glucose content had a tendency to increase as storage duration extended. Pyruvic acid/total sugar (PA/TS) ratio decreased after 1 month of storage, and then increased after 135 days, and was 83% higher at 150 days of storage than at harvest. Sweetness gradually decreased until 1 month of storage, but thereafter remained steady. Therefore it is desirable that pyruvic acid analysis for sweet onion selection should be conducted before breaking the dormancy.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.3
• /
• pp.234-238
• /
• 1990

The effects of salt concentration immersion time in a salt solution prior to air dehydration and heating of air temperature during dehydration upon the browning reaction and pyruvic acid content of air dried garlics to a 6.5% moisture content(wet basis) were analyzed by a response surface methodology(RSM), Those values were also predicted by using a second degree polynomial regression model. Heating of air temperature was the most significant factor affecting the both browning reaction and pyruvic acid content. Salt concentration had more influence to browning reaction than immersion time whereas immersion time was more impor-tant factor than salt concentration on a retention of pyruvic acid sugested different processing conditions. While the processing conditions to minimize the browning reaction(O.D=0.009) were 0.3% of salt solution 9 min of immersion time and 5$0^{\circ}C$ of air temperature compared to control(O.D=0.022) of air dehydration at 5$0^{\circ}C$ Pyruvic acid contents were maximized(174 $\mu$mole/g garlic solid) at the 0.1% of salt solution 3 min of immersion time and 5$0^{\circ}C$ of air temperature compared to control(147 $\mu$mole/g garlic solid) of air dehydration at 5$0^{\circ}C$

• Korean Journal of Food Science and Technology
• /
• v.22 no.5
• /
• pp.539-542
• /
• 1990

The effects of immersion temperature $(20,\;40\;and\;60^{\circ}C)$ and immersion times (6. 12 and 18 min) in a distilled water prior to air dehydration upon the browning reaction and pyruvic acid content of air dried onions to a 4.071 moisture content (wet basis) were analyzed by a response surface methodology (RSM). Those values were also predicted by using a second degree polynomial regression model. Immersion temperature had more influence to browning reaction and pyruvic acid content than immersion time in these experimental ranges. The processing conditions to minimize the browning reaction of dried onions at $50^{\circ}C$ of air temperature (O.D.=0.071) were $60^{\circ}C$ of immersion temperature and 18 min of immersion time compared to control (O.D.=0.168) of air dehydration at $50^{\circ}C$ Pyruvic acid contents of dried onions at $50^{\circ}C$ of air temperature were maximized $(39.85{\mu}mole/g\;onion\;solid)$ at $60^{\circ}C$ of immersion temperature and 12 min of immersion time compared to control $(24.08{\mu}mole/g\;onion\;solid)$ of air dehydration at $50^{\circ}C$.

• Food Science and Preservation
• /
• v.5 no.2
• /
• pp.111-117
• /
• 1998

Biochemical property changes of garlic during various storages and marketing after storage were investigated. Content of enzymatic pyruvic acid increased by room and low temperature storage but decreased by CA and MA storage. Fructan contents decreased rapidly by low temperature storage, but restrained decrement by CA and MA storage. Free sugar increased during storage, but did slowly by room temperature storage. Green pigment development was observed when garlics stored for 90days at low temperature were processed into crushed form. This discoloration was small for garlics stored in CA and MA, and never occurred for room temperature stored garlics. When marketed after storage, content of enzymatic pyruvic acid decreased in garlic stored in room and low temperature storage, but increased in garlics which decreased during CA and MA storage. Fructan contents deceased but free sugar contents continuously increased with marketing period. Green pigment development decreased in crushed garlic after 30days at room temperature marketing, but increased in low temperature marketing with marketing time progress.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 2005.10a
• /
• pp.114-117
• /
• 2005

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.22 no.1
• /
• pp.78-84
• /
• 1993

This study was conducted to investigate the effect of various polyethylene (PE) film packaging on the quality of strawberry during storage at low temperature. Gas composition in film was changed rapidly at early stage of storage and then kept at the level of 5~10% $CO_2$and 1~3% $O_2$. Weight loss and decay rate were low at 0.08mm PE film packed strawberries. Titratable acidity, pH and soluble solids were changed slightly during storage but its large difference according to film thickness was not observed. Decrease of flesh firm-ness and a value was restrained by PE film packaging. Free sugar of strawberry was composed of glucose and fructose in similar content and it was decreased a little during storage but the difference according to film thickness was not observed. The organic acids in strawberry were citric acid, malic acid, succinic acid, ascorbir acid, oxalic acid, tartaric acid and pyruvic acid and the major organic acid was citric acid. The contents of citric acid, malic acid, succinir acid and ascorbic acid were decreased and oxalic acid and tartaric arid were not changed during storage but pyruvic acid was increased in early stage and then decreased. These changes of organic acid were slight in packaged with 0.08mm PE film strawberry.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.6
• /
• pp.578-584
• /
• 2000

Three kinds of the mashes of 15%, 20% and 25% of boiled wax gourd containing 20% of sugar were fermented by yeast at 5~1$0^{\circ}C$ for 100 days. After fermentation, total sugar content of the 15% mash was 8.0%, 20% mash 8.6%, and 25% mash 8.3%, respectively. Also, it revealed that in reducing sugar content, 15% mash was 7.4%, 20% mash 7.6%, and 25% mash 7.4%, respectively, In protein content, 15% mash was 10.3mg/ml, 20% mash 9.8mg/ml, and 25% mash 11.3mg/ml, and in amino acid content, 15% mash was 0.13 $\mu$mo1/ml, 20% mash 0.03 $\mu$mo1/ml, and 25% mash 0.03 $\mu$mo1/ml, each. In case of pH, 15% mash was 3.88, 20% mash 3.99, and 25% mash 3.97, respectively. In acidity, 15% mash was 0.37, 20% mash 0.44. and 25% mash 0.43, respectively. In the number of yeast cell, 15% mash was 8.33 logCFU/ml, 20% mash 8.56 logCFU/ml, and 25% mash 8.57 logCFU/ml. respectively. In ethanol content, 15% mash was 13.4%, 20% mash 14.9%, and 25% mash 15.5%, respectively. In organic acid content, acetic acid, pyruvic acid, citric acid, and lactic acid were produced, and succinic acid content ranges from 1,407~1,800 mg/l. Five-grade scoring test of sensory evaluation showed that in its taste degree, 15% mash was 3.93, 20% mash 3.66 and 25% mash 3.40, respectively.