Pub Date : 1998-05-25DOI: 10.3136/FSTI9596T9798.4.130
K. Hayakawa, Jing He
Charts were prepared for estimating local maxima or minima of dimensionless, principal stresses of axial, radial, and tangential orientations formed in an elastic, cylindrical food during a drying or hydrating process. For this, analytical solutions derived previously were used. These charts showed that tangential stresses were the most critical for stress cracking during drying processes and radial stresses for hydrating processes. Sample applications of the charts were presented for adjusting process conditions to prevent stress cracking.
{"title":"Maximum Hygrostress Response Charts for Drying or Hydrating Elastic, Cylindrical Food with Infinite Biot Number.","authors":"K. Hayakawa, Jing He","doi":"10.3136/FSTI9596T9798.4.130","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.130","url":null,"abstract":"Charts were prepared for estimating local maxima or minima of dimensionless, principal stresses of axial, radial, and tangential orientations formed in an elastic, cylindrical food during a drying or hydrating process. For this, analytical solutions derived previously were used. These charts showed that tangential stresses were the most critical for stress cracking during drying processes and radial stresses for hydrating processes. Sample applications of the charts were presented for adjusting process conditions to prevent stress cracking.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"168 1","pages":"130-135"},"PeriodicalIF":0.0,"publicationDate":"1998-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76761886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-05-25DOI: 10.3136/FSTI9596T9798.4.121
Youichi Yoshii, Masami Arisaka, T. Joh, T. Hayakawa
This study was conducted to determine the reason why dried rice cakes for non-glutinous rice crackers (Senbei) often break in the production process. Breakage after drying at 40°C for 12 h was found to be due to milling and storage conditions of the rice flour. Gel permeation chromatography revealed that the molecular weight of starch decreased as the extent of breakage increased. Damage to rice flour starch differed according to the milling methods. When press roller milled rice flour was stored at 5-25°C, the activity of α-amylase increased as the temperature became higher. The total water-soluble carbohydrate content of dried rice cake may be a good criterion to judge the extent of breakage. Reduction of the molecular sizes of starch, due to milling and action of α-amylase, is considered to cause the breakage of dried rice cake.
{"title":"Effect of Starch Properties on the Extent of Breakage of Non-Glutinous Dried Rice Cake","authors":"Youichi Yoshii, Masami Arisaka, T. Joh, T. Hayakawa","doi":"10.3136/FSTI9596T9798.4.121","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.121","url":null,"abstract":"This study was conducted to determine the reason why dried rice cakes for non-glutinous rice crackers (Senbei) often break in the production process. Breakage after drying at 40°C for 12 h was found to be due to milling and storage conditions of the rice flour. Gel permeation chromatography revealed that the molecular weight of starch decreased as the extent of breakage increased. Damage to rice flour starch differed according to the milling methods. When press roller milled rice flour was stored at 5-25°C, the activity of α-amylase increased as the temperature became higher. The total water-soluble carbohydrate content of dried rice cake may be a good criterion to judge the extent of breakage. Reduction of the molecular sizes of starch, due to milling and action of α-amylase, is considered to cause the breakage of dried rice cake.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"55 1","pages":"121-124"},"PeriodicalIF":0.0,"publicationDate":"1998-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84732858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-05-25DOI: 10.3136/FSTI9596T9798.4.125
Makoto Ito, M. Roy, K. Kurihara, Yasuo Watanabe, Y. Kuwabara, Seiichiro Nagai, Y. Tamai
{"title":"Effects of Bovine Milk Fermented by Culturing with Lactic Acid Bacteria and a Yeast on the Proliferation Activity of Human Carcinoma Cells.","authors":"Makoto Ito, M. Roy, K. Kurihara, Yasuo Watanabe, Y. Kuwabara, Seiichiro Nagai, Y. Tamai","doi":"10.3136/FSTI9596T9798.4.125","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.125","url":null,"abstract":"","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"386 1","pages":"125-129"},"PeriodicalIF":0.0,"publicationDate":"1998-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76594722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-05-25DOI: 10.3136/FSTI9596T9798.4.143
K. Miyamoto, Miyuki Kawauchi, Toshitaka Fukuda
On-line measurement of sugar content in satsuma mandarins was already achieved using NIR transmittance spectroscopy. The feasibility of simultaneous measurement of citric acid content was investigated. The citric acid content determined by titration with NaOH and the second derivative absorption values autoscaled in the 710-930 nm region were analyzed by PLS1 using Unscrambler software. The spectra of peeled fruits measured by an NIR Systems Model 6250 were analyzed, and the model composed of 12 factors indicated the highest accuracy; R was 0.93, the mean residual (Bias) was -0.013% and the standard error of prediction (SEP) was 0.146%. The citric acid content in intact satsuma mandarins was regressed by the same method using an on-line instrument. The model composed of 5 factors calibrated from 689 samples showed the highest accuracy; R=0.83, Bias=0.024% and SEP=0.147% as a prediction result from 548 samples. It was possible to classify nondestructively the high acid fruits using near infrared (NIR) transmittance spectroscopy at about 20% error rate.
{"title":"Classification of High Acid Satsuma Mandarins by Near Infrared Transmittance Spectroscopy","authors":"K. Miyamoto, Miyuki Kawauchi, Toshitaka Fukuda","doi":"10.3136/FSTI9596T9798.4.143","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.143","url":null,"abstract":"On-line measurement of sugar content in satsuma mandarins was already achieved using NIR transmittance spectroscopy. The feasibility of simultaneous measurement of citric acid content was investigated. The citric acid content determined by titration with NaOH and the second derivative absorption values autoscaled in the 710-930 nm region were analyzed by PLS1 using Unscrambler software. The spectra of peeled fruits measured by an NIR Systems Model 6250 were analyzed, and the model composed of 12 factors indicated the highest accuracy; R was 0.93, the mean residual (Bias) was -0.013% and the standard error of prediction (SEP) was 0.146%. The citric acid content in intact satsuma mandarins was regressed by the same method using an on-line instrument. The model composed of 5 factors calibrated from 689 samples showed the highest accuracy; R=0.83, Bias=0.024% and SEP=0.147% as a prediction result from 548 samples. It was possible to classify nondestructively the high acid fruits using near infrared (NIR) transmittance spectroscopy at about 20% error rate.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"35 1","pages":"143-148"},"PeriodicalIF":0.0,"publicationDate":"1998-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77540252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-05-25DOI: 10.3136/FSTI9596T9798.4.159
K. Iwashita, M. Kobori, H. Shinmoto, T. Tsushida
Eggplant extract markedly inhibited melanogenesis in B16 mouse melanoma 4A5 cells (B16 cells). To clarify the characteristics of the melanogenesis inhibitor in eggplant, the effective fraction, P1, was separated from the eggplant extract by ammonium sulfate fractionation and Sephadex G-100 column chromatography. The P1 fraction from the eggplant contained 63% protein, 20% neutral sugar and 11% uronic acid. P1 was stable during heating at 60°C for 30 min, and the inhibitory effect remained stable after protease digestion. P1 weakly inhibited tyrosinase activity in crude B16 cell extract in vitro, and tyrosinase activity in B16 cells cultured with P1 was reduced. The regulation of tyrosinase activity in B16 cells was equal to melanogenesis suppression in B16 cells. These results show that the eggplant extract suppresses melanogenesis in B16 cells by regulation of tyrosinase.
{"title":"Eggplant Extract Inhibits Melanogenesis in B16 Melanoma Cells","authors":"K. Iwashita, M. Kobori, H. Shinmoto, T. Tsushida","doi":"10.3136/FSTI9596T9798.4.159","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.159","url":null,"abstract":"Eggplant extract markedly inhibited melanogenesis in B16 mouse melanoma 4A5 cells (B16 cells). To clarify the characteristics of the melanogenesis inhibitor in eggplant, the effective fraction, P1, was separated from the eggplant extract by ammonium sulfate fractionation and Sephadex G-100 column chromatography. The P1 fraction from the eggplant contained 63% protein, 20% neutral sugar and 11% uronic acid. P1 was stable during heating at 60°C for 30 min, and the inhibitory effect remained stable after protease digestion. P1 weakly inhibited tyrosinase activity in crude B16 cell extract in vitro, and tyrosinase activity in B16 cells cultured with P1 was reduced. The regulation of tyrosinase activity in B16 cells was equal to melanogenesis suppression in B16 cells. These results show that the eggplant extract suppresses melanogenesis in B16 cells by regulation of tyrosinase.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"43 1","pages":"159-163"},"PeriodicalIF":0.0,"publicationDate":"1998-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77716931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-05-25DOI: 10.3136/FSTI9596T9798.4.114
Toru Hayashi
Electrons with energies of 300 keV or lower (soft-electrons) reduced microbial loads of grains, pulses, spices, dehydrated vegetables and seeds to levels lower than 10 CFU/g. The viscosity of gelatinized grain powder suspension (parameter for starch degradation) showed no significant difference between untreated grains and soft-electron treated ones, which indicated that soft-electrons did not significantly degrade the starch molecules of grains. Electrons with a higher energy with a higher penetration capacity resulted in a higher thiobarbituric acid value (TBA, parameter for lipid oxidation) of brown rice. Milling rice at a yield of 90% or 88% after electron treatment made the TBA of rice treated with electrons at 65 keV almost the same as that of untreated rice. The results indicated that the milling process removed the portion of brown rice exposed to soft-electrons. Seeds which were exposed to soft-electrons showed the same sprouting capacity as untreated seeds. Soft-electrons could eradicate microorganisms on the surface of dry food ingredients and seeds with little adverse effects on quality and sprouting capacity.
{"title":"Decontamination of Dry Food Ingredients and Seeds with “Soft-Electrons” (Low-Energy Electrons)","authors":"Toru Hayashi","doi":"10.3136/FSTI9596T9798.4.114","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.114","url":null,"abstract":"Electrons with energies of 300 keV or lower (soft-electrons) reduced microbial loads of grains, pulses, spices, dehydrated vegetables and seeds to levels lower than 10 CFU/g. The viscosity of gelatinized grain powder suspension (parameter for starch degradation) showed no significant difference between untreated grains and soft-electron treated ones, which indicated that soft-electrons did not significantly degrade the starch molecules of grains. Electrons with a higher energy with a higher penetration capacity resulted in a higher thiobarbituric acid value (TBA, parameter for lipid oxidation) of brown rice. Milling rice at a yield of 90% or 88% after electron treatment made the TBA of rice treated with electrons at 65 keV almost the same as that of untreated rice. The results indicated that the milling process removed the portion of brown rice exposed to soft-electrons. Seeds which were exposed to soft-electrons showed the same sprouting capacity as untreated seeds. Soft-electrons could eradicate microorganisms on the surface of dry food ingredients and seeds with little adverse effects on quality and sprouting capacity.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"4 1","pages":"114-120"},"PeriodicalIF":0.0,"publicationDate":"1998-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83518411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-05-25DOI: 10.3136/FSTI9596T9798.4.136
P. Owuor, M. Obanda
Enriching the atmosphere of fermenting “dhool” (macerated leaf) with oxygen led to faster production of some black tea volatile flavor compounds (VFC). There was a general rise in the total amounts of the VFC with long fermentation duration irrespective of whether it was done under enriched oxygen atmosphere or ambient air. The rise was, however faster under enriched oxygen atmosphere than under ambient air. The rise was also faster in the group I VFC than the group II VFC leading to a general decline in the Flavor Index with long fermentation durations. For every fermentation duration, the sum of group I VFC was higher under enriched oxygen atmosphere than under ambient air fermentation. Such variations were only marginal in the group II VFC. As a result, fermentation under enriched oxygen atmosphere reduced the aroma quality of black tea despite increasing the total amounts of VFC. Generally, the VFC which are oxidative products of amino acids and unsaturated fatty acids degradation increased with fermentation durations, while the major terpene alcohols declined under both ambient air and enriched oxygen atmosphere fermentation conditions.
{"title":"Effects of Fermentation under Enriched Oxygen Atmosphere on Clonal Black Tea Aroma Complex","authors":"P. Owuor, M. Obanda","doi":"10.3136/FSTI9596T9798.4.136","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.136","url":null,"abstract":"Enriching the atmosphere of fermenting “dhool” (macerated leaf) with oxygen led to faster production of some black tea volatile flavor compounds (VFC). There was a general rise in the total amounts of the VFC with long fermentation duration irrespective of whether it was done under enriched oxygen atmosphere or ambient air. The rise was, however faster under enriched oxygen atmosphere than under ambient air. The rise was also faster in the group I VFC than the group II VFC leading to a general decline in the Flavor Index with long fermentation durations. For every fermentation duration, the sum of group I VFC was higher under enriched oxygen atmosphere than under ambient air fermentation. Such variations were only marginal in the group II VFC. As a result, fermentation under enriched oxygen atmosphere reduced the aroma quality of black tea despite increasing the total amounts of VFC. Generally, the VFC which are oxidative products of amino acids and unsaturated fatty acids degradation increased with fermentation durations, while the major terpene alcohols declined under both ambient air and enriched oxygen atmosphere fermentation conditions.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"2 1","pages":"136-139"},"PeriodicalIF":0.0,"publicationDate":"1998-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90057096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-25DOI: 10.3136/FSTI9596T9798.4.6
M. Yasuda, Maki Sakaguchi
Degradation of soybean protein by Monascus-proteinase was investigated in order to reveal the role of the enzyme in the process of tofuyo ripening. The ratio of trichloroacetic acid-insoluble nitrogen of soybean protein to the total nitrogen in the reaction mixture decreased with increasing enzymatic reaction time. It was found that the digestion of soybean protein by this enzyme progressed as follows: initially, α'-, α-, and β-subunits in β-conglycinin, and then, the acidic subunit in glycinin were degraded. However, the basic subunit of glycinin still remained, and some polypeptide bands (around 10 kDa) were formed during the enzyme reaction. The degradation rate of soybean protein by this enzyme was affected by the ethyl alcohol concentration in the reaction mixtures.
{"title":"Degradation of Soybean Protein by an Acid Proteinase from Monascus anka","authors":"M. Yasuda, Maki Sakaguchi","doi":"10.3136/FSTI9596T9798.4.6","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.6","url":null,"abstract":"Degradation of soybean protein by Monascus-proteinase was investigated in order to reveal the role of the enzyme in the process of tofuyo ripening. The ratio of trichloroacetic acid-insoluble nitrogen of soybean protein to the total nitrogen in the reaction mixture decreased with increasing enzymatic reaction time. It was found that the digestion of soybean protein by this enzyme progressed as follows: initially, α'-, α-, and β-subunits in β-conglycinin, and then, the acidic subunit in glycinin were degraded. However, the basic subunit of glycinin still remained, and some polypeptide bands (around 10 kDa) were formed during the enzyme reaction. The degradation rate of soybean protein by this enzyme was affected by the ethyl alcohol concentration in the reaction mixtures.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"59 1","pages":"6-8"},"PeriodicalIF":0.0,"publicationDate":"1998-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77368126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-25DOI: 10.3136/FSTI9596T9798.4.29
Y. Miyake, Keiko Kuzuya, C. Ueno, N. Katayama, T. Hayakawa, H. Tsuge, T. Osawa
The effects of lemon juice and its crude flavonoids on blood pressure were examined using spontaneously hypertensive rats (SHR). The 5% diluted lemon juice was orally administered in the diet to SHR, and they tended to have a lower systolic blood pressure than the control rats after 90 days. The systolic blood pressure of SHR fed a diet containing crude flavonoids from the juice for 16 weeks was significantly lower than that of the control group (p<0.05). The systolic blood pressure with administration of fraction B, which was fractionated from the crude flavonoids, was significantly lower (p<0.05) after 4 weeks. The crude flavonoids and fraction B contained abundant flavonoid glycosides of eriocitrin, hesperidin, and 6,8-di-C-β-glucosyldiosmin as determined by high performance liquid chromatography (HPLC) analysis. The crude flavonoids and the flavonoid glycosides had an inhibitory effect on angiotensin I converting enzyme (ACE).
采用自发性高血压大鼠(SHR)研究柠檬汁及其黄酮对血压的影响。在饮食中口服5%稀释的柠檬汁给SHR, 90天后，它们的收缩压往往比对照大鼠低。饲粮中添加黄酮类化合物16周后，SHR的收缩压显著低于对照组(p<0.05)。4周后，大鼠收缩压显著降低(p<0.05)。经高效液相色谱(HPLC)分析，粗黄酮和提取物B中含有丰富的eriocitrin、橙皮苷和6,8-di- c -β-glucosyldiosmin类黄酮苷。粗黄酮和黄酮类苷对血管紧张素I转换酶(ACE)有抑制作用。
{"title":"Suppressive Effect of Components in Lemon Juice on Blood Pressure in Spontaneously Hypertensive Rats","authors":"Y. Miyake, Keiko Kuzuya, C. Ueno, N. Katayama, T. Hayakawa, H. Tsuge, T. Osawa","doi":"10.3136/FSTI9596T9798.4.29","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.29","url":null,"abstract":"The effects of lemon juice and its crude flavonoids on blood pressure were examined using spontaneously hypertensive rats (SHR). The 5% diluted lemon juice was orally administered in the diet to SHR, and they tended to have a lower systolic blood pressure than the control rats after 90 days. The systolic blood pressure of SHR fed a diet containing crude flavonoids from the juice for 16 weeks was significantly lower than that of the control group (p<0.05). The systolic blood pressure with administration of fraction B, which was fractionated from the crude flavonoids, was significantly lower (p<0.05) after 4 weeks. The crude flavonoids and fraction B contained abundant flavonoid glycosides of eriocitrin, hesperidin, and 6,8-di-C-β-glucosyldiosmin as determined by high performance liquid chromatography (HPLC) analysis. The crude flavonoids and the flavonoid glycosides had an inhibitory effect on angiotensin I converting enzyme (ACE).","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"52 1","pages":"29-32"},"PeriodicalIF":0.0,"publicationDate":"1998-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85720504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-25DOI: 10.3136/FSTI9596T9798.4.66
K. Yoshikawa, P. Aryal, T. Terashita, Jiko Sishiyama, D. Shankel
Modifications of the standard Ames test and umu test were employed to study the “desmutagenic” response exerted by pheophytin b against the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). The mixture from which pheophytin b separated was activated with S9 mix and was assayed to determine the remaining mutagenicity of Trp-P-2. The decrease in the His+ revertant colonies of Salmonella typhimurium TA98 was dependent on the increase in pheophytin b concentrations. Binding of Trp-P-2 to DNA and the subsequent induction of the SOS response were investigated using the umu test employing Salmonella typhimurium NM 2009. Trp-P-2 induced induction of β-galactosidase was suppressed when pheophytin b was included in the test. In order to evaluate the mode of action of pheophytin b in the mixture of Trp-P-2, Trp-P-2 was analyzed using HPLC. Compared with a solution of Trp-P-2 alone, the absorbance peak of Trp-P-2 in the HPLC profile of the mixture of Trp-P-2 and pheophytin b was observed to be decreased. Also a new peak was not shown in the HPLC profile. To investigate the possible effect of pheophytin b on the S9 mix, the HPLC profile of a mixture containing Trp-P-2, S9 mix and pheophytin b was compared with a mixture containing only Trp-P-2 and S9 mix. The absorbance peak of the hydroxylated Trp-P-2 in the reaction mixture containing pheophytin b was observed to be smaller than the peak of the mixture without pheophytin b. From these results, it is suggested that pheophytin b limits the formation of hydroxylated Trp-P-2.
{"title":"Desmutagenic Effect of Pheophytin b against Trp-P-2 in the Salmonella Assay","authors":"K. Yoshikawa, P. Aryal, T. Terashita, Jiko Sishiyama, D. Shankel","doi":"10.3136/FSTI9596T9798.4.66","DOIUrl":"https://doi.org/10.3136/FSTI9596T9798.4.66","url":null,"abstract":"Modifications of the standard Ames test and umu test were employed to study the “desmutagenic” response exerted by pheophytin b against the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). The mixture from which pheophytin b separated was activated with S9 mix and was assayed to determine the remaining mutagenicity of Trp-P-2. The decrease in the His+ revertant colonies of Salmonella typhimurium TA98 was dependent on the increase in pheophytin b concentrations. Binding of Trp-P-2 to DNA and the subsequent induction of the SOS response were investigated using the umu test employing Salmonella typhimurium NM 2009. Trp-P-2 induced induction of β-galactosidase was suppressed when pheophytin b was included in the test. In order to evaluate the mode of action of pheophytin b in the mixture of Trp-P-2, Trp-P-2 was analyzed using HPLC. Compared with a solution of Trp-P-2 alone, the absorbance peak of Trp-P-2 in the HPLC profile of the mixture of Trp-P-2 and pheophytin b was observed to be decreased. Also a new peak was not shown in the HPLC profile. To investigate the possible effect of pheophytin b on the S9 mix, the HPLC profile of a mixture containing Trp-P-2, S9 mix and pheophytin b was compared with a mixture containing only Trp-P-2 and S9 mix. The absorbance peak of the hydroxylated Trp-P-2 in the reaction mixture containing pheophytin b was observed to be smaller than the peak of the mixture without pheophytin b. From these results, it is suggested that pheophytin b limits the formation of hydroxylated Trp-P-2.","PeriodicalId":12457,"journal":{"name":"Food Science and Technology International, Tokyo","volume":"1 1","pages":"66-70"},"PeriodicalIF":0.0,"publicationDate":"1998-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89687300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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