Food Science and Technology Research
Online ISSN : 1881-3984
Print ISSN : 1344-6606
ISSN-L : 1344-6606
Volume 21 , Issue 3
Showing 1-28 articles out of 28 articles from the selected issue
Food Technology and Engineering
Original papers
  • Daiki Murayama, Tomone Kimura, Kazumasa Tsuboi, Daiju Yamada, Dennis M ...
    2015 Volume 21 Issue 3 Pages 285-290
    Published: 2015
    Released: September 10, 2015
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    Five different potato flours were prepared from the table potato variety, May Queen, by drying potato slices without boiling or refrigeration (D), with boiling for 10 or 30 min (10B, 30B) and with boiling for 10 or 30 min, followed by refrigeration (10BR, 30BR), and their applicability to bread making was evaluated. When 10% potato flour was added to strong wheat flour (S), B and BR increased the water absorption of dough and lowered the gas retention of dough (GRD) and specific loaf volume (SLV). However, the highest GRD and SLV were observed in a combination of S with 10BR among the tested flour blends. Furthermore, GRD and SLV were improved by replacing S with extra-strong wheat flour (ES). The bread made from ES and 10BR maintained significantly higher softness of crumb compared to control during 3 days of storage at 20°C (p < 0.05).
  • Yuta Umeno, Fumihiko Tanaka, Junichi Otsuji, Hideo Shidara, Toshitaka ...
    2015 Volume 21 Issue 3 Pages 291-295
    Published: 2015
    Released: September 10, 2015
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    Steam infusion is a pasteurization method used for liquid food such as milk. As the first step in the optimization of the flow rate of milk in the steam infusion chamber, two computational fluid dynamics (CFD) simulations predicted droplet generation from injection water into air and an experiment was carried out. Model 1 only consisted of a nozzle and a region of air. Model 2 consisted of a nozzle, a stainless steel pipe and a region of air. These results were evaluated by the breakup length and projected area. The breakup lengths in the experiment, Model 1 and Model 2 were 94.0 mm, 254.6 mm and 92.1 mm, respectively. The breakup length in Model 1 differed from the experimental data. The projected area in the experiment and Model 2 was 524.5 mm2 and 536.6 mm2, respectively. Both results for Model 2 agreed with the experimental results. Model 2 successfully expressed droplet generation.
  • Noriyuki Kitamoto, Natsuko Ono, Shoko Yoshino-Yasuda
    2015 Volume 21 Issue 3 Pages 297-307
    Published: 2015
    Released: September 10, 2015
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    We constructed a quintuple protease (alp, npII, pepE, npI, pepA) and double amylase (taaG3, taaG1) gene deletant, KO4, for the development of a heterologous gene expression system for an industrial shoyu koji mold, Aspergillus oryzae KBN616. Multiple gene deletion was performed using the Latour system, a simple and effective chromosome modification method developed in Schizosaccharomyces pombe. Gene deletion was confirmed by Southern blot analysis for protease genes and PCR amplification for amylase genes. Deletion of the five protease genes reduced the extracellular protease activity to approximately 1.0% of the level of the parent strain. Double deletion of the amylase genes completely eliminated all detectable α-amylase activity. These results indicate the construction of a host strain applicable to the efficient production and purification of heterologous proteins.
  • Naomi Morimoto, Aya Tabara, Masaharu Seguchi
    2015 Volume 21 Issue 3 Pages 309-316
    Published: 2015
    Released: September 10, 2015
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    Wheat flour was preliminarily mixed with 5% polysaccharides (locust bean gum, guar gum, xanthan gum, tamarind seed gum, native gellan gum, dextrin, LM pectin, fermented cellulose CMC, konjac glucomannan, HM pectin, κ-carrageenan, ι-carrageenan, and λ-carrageenan), and then mixed with water, salt, sugar, and yeast, followed by proofing. Next, the proofed bread dough was divided into two, frozen at −20°C for 6 d, and then thawed at 4°C for 16 h. One part of the dough was baked at 210°C for 30 min, and the other was subjected to determination of the extruded liquid from the thawed dough upon centrifugation. As the results, frozen/thawed control (wheat flour) dough presented a lower bread height (mm), lower specific volume (cm3/g), and a higher volume of exuded liquid than unfrozen dough. When polysaccharides such as guar gum, xanthan gum, and tamarind seed gum were mixed with the flour prior to making the bread dough, similar or greater bread height and specific volume than those of bread baked with unfrozen control dough were obtained. The greatest increases in bread height and specific volume on supplementation of polysaccharides were observed when xanthan gum was used. In order to clarify why xanthan gum markedly improved the breadmaking properties, oven-spring tests were conducted for 10, 15, 20, and 30 min in a 210°C oven. The breadmaking properties (bread height) of baking with frozen/thawed control dough increased until 10 min in the 210°C oven and then stopped. However, for the bread with xanthan gum, these variables did not stop increasing.
Technical paper
Notes
  • Savitree Ratanasumawong, Tomoaki Hagiwara, Takaharu Sakiyama
    2015 Volume 21 Issue 3 Pages 327-331
    Published: 2015
    Released: September 10, 2015
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    Cross-contamination of protein deposits to other food products can cause serious issues in food plants, where several products might be processed using the same equipment. The key to preventing cross-contamination of foods is the thorough cleaning of work surfaces. To establish an optimum cleaning process for such equipment, understanding of the adhesion behavior of proteins on food-contact surfaces is important. This work aims to examine the effect of sodium chloride (NaCl) on the adsorption of shrimp proteins onto stainless steel surfaces. The presence of NaCl during extraction slightly increased the ratio of adsorbed total protein, while that of the protein tropomyosin, a major shrimp allergen, decreased. The addition of NaCl to the shrimp protein extract post-extraction had no effect on the ratios of adsorbed total protein and tropomyosin. The addition of NaCl during extraction affected both the protein composition of the extract and the major type of protein adsorbed onto stainless steel surfaces.
  • Manami Monobe, Sachiko Nomura, Kaori Ema, Akiko Matsunaga, Atsushi Nes ...
    2015 Volume 21 Issue 3 Pages 333-340
    Published: 2015
    Released: September 10, 2015
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    In an effort to identify tea cultivars with high flavonol content, we measured flavonol glycoside levels in the tea infusions of cultivars in the collection of the National Institute of Vegetable and Tea Science. The cultivars ‘Saemidori’, ‘Sofu’, ‘Surugawase’, ‘Fukumidori’, and ‘Asatsuyu’ among others could be effective sources of quercetin compared to other tea cultivars. Quercetin glycosides in “Saemidori” and “Sofu” remained at a relatively high level (110 – 170 µg/mL aglycone equivalent). These cultivars are indicated as effective sources of dietary quercetin, and are potential sources of quercetin-rich drinks.
  • Tomoaki Hagiwara, Madoka Suzuki, Yuki Hasegawa, Saki Isago, Hisahiko W ...
    2015 Volume 21 Issue 3 Pages 341-345
    Published: 2015
    Released: September 10, 2015
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    To improve the cleaning efficiency of food production equipment, it is crucial to understand the formation of protein deposits. This study examined the adsorption behavior of shrimp (pink shrimp, Pandalus eous) proteins onto a stainless steel surface at temperatures of 30 – 95°C, using a shrimp extract solution as a model shrimp food. At temperatures above 60°C, the total amount of adsorbed proteins increased rapidly. However, the adsorption ratio of tropomyosin, a major shrimp allergen, tended to decrease. Results of FT-IR analysis of heated shrimp extract solutions suggested that the intermolecular aggregation, occurring by thermal denaturation of proteins in the extract above 60°C, affected the adsorption behavior of proteins. SDS-PAGE of the extract solutions before and after the adsorption procedure showed that the type of adsorbed proteins onto the stainless steel surface changed markedly at temperatures above 60°C.
  • Ittetsu Yamaga, Testuya Takahashi, Kanako Ishii, Mitsuhiro Kato, Yasus ...
    2015 Volume 21 Issue 3 Pages 347-351
    Published: 2015
    Released: September 10, 2015
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    Blue mold (Penicillium italicum) is a major postharvest pathogen of citrus. Here, we investigated the mitigating effect of blue light-emitting diode (LED) irradiation on blue mold in satsuma mandarin (Citrus unshiu Marc.) fruit after harvesting. We examined the growth and development of blue mold subjected to blue LED irradiation of two different intensities in vitro. High-intensity blue LED with an emission peak of 465 nm and fluency of 80 µmol·m−2·s−1, and low-intensity blue LED with an emission peak of 465 nm and fluency of 8 µmol·m−2·s−1 significantly reduced the growth of P. italicum. In addition, wounded fruits inoculated with P. italicum were irradiated with high- and low-intensity blue LED for 6 days and changes in blue mold symptoms were monitored. The results indicate that not only high-intensity, but also low-intensity blue LED treatment significantly reduced blue mold symptoms in fruit; the most pronounced inhibitory effect was exerted on P. italicum sporulation. These results show that treatment with low-intensity blue LED irradiation is sufficient to reduce blue mold symptom development and is a promising safe approach to control postharvest spoilage in mandarin fruit.
  • Takayuki Miura, Kaori Tokumaru, Ryozo Akuzawa
    2015 Volume 21 Issue 3 Pages 353-357
    Published: 2015
    Released: September 10, 2015
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    The application of cooking water abundant in phenolic compounds, obtained from cooking three types of beans (black soybean, yellow soybean and adzuki bean) and chestnut inner shell, to functional cheese product manufacturing was evaluated. Total phenolics in the cooking water were estimated by the Folin-Ciocalteu colorimetric method and showed a wide range, from 24.4 to 761 µg/mL. The antioxidant activity of extracts was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging and oxygen radical antioxidant activity (ORAC) assays. Results of both antioxidant assays showed similar trends in total phenolic content; DPPH values ranged from 24.6 to 309.3 µmol TE/mL, while ORAC values ranged from 30.6 to 325 µmol TE/mL.High estimated residual phenolic values were observed for cheese curd made with chestnut inner shell, yellow soybean, adzuki bean and black soybean extracts; 96, 87.2, 84.9 and 82.3%, respectively.
Food Science and Chemistry
Original papers
  • Toshihiro Ito, Mitsutoshi Nakajima, Seiichiro Isobe
    2015 Volume 21 Issue 3 Pages 359-364
    Published: 2015
    Released: September 10, 2015
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    Cornstarch was extruded using various feed moistures and screw speeds with and without soybean oil. We investigated the effects of each variable and interactions between variables on extrudate characteristics. In starch, the positive linear effect of screw speed and the negative effect of the interaction between moisture and screw speed were significant factors in the degree of gelatinization (DG). The positive linear effect of feed moisture and screw speed and their negative interaction were significant factors in the oil-added extrudates. The water absorption index (WAI) of both extrudates was determined by the linear and quadratic effect of feed moisture and the negative interaction between the two variables. In starch, the positive quadratic effect of moisture and screw speed and their negative interaction affected the water solubility index (WSI). In the oil-added extrudates, the negative effect of feed moisture and the negative interaction of screw speed and feed moisture influenced WSI.
  • Vipavee Trivittayasil, Kohei Nashiro, Fumihiko Tanaka, Daisuke Hamanak ...
    2015 Volume 21 Issue 3 Pages 365-370
    Published: 2015
    Released: September 10, 2015
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    Inactivation characteristics by UV-C radiation of Cladosporium cladosporioides and Penicillium digitatum, known as decay-inducing molds on fruits, were investigated. The survival curve of C. cladosporioides with irradiation dose was found to be biphasic in nature; the inactivation rate was initially high and slowed with increasing irradiation dose. In contrast, the survival curve of P. digitatum was approximately linear. A shoulder on the survival curves of both species was observed at low dose, indicating their resistance to low-dose UV-C. The mathematical model representing the inactivation of C. cladosporioides was the biphasic linear model, whereas the first-order kinetics model was applicable to P. digitatum.
  • Zuobing Xiao, Xin Dai, Jiancai Zhu, Haiyan Yu
    2015 Volume 21 Issue 3 Pages 371-380
    Published: 2015
    Released: September 10, 2015
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    The feasibility of the discrimination of Chinese rice wines with respect to their geographic origin and wine age using volatile profiles and chemometric methods was investigated. Stir bar sorptive extraction with thermal desorption and gas chromatography-mass spectrometry (SBSE-TD-GC-MS) was used for the determination of volatile compounds. A total of 63 volatile compounds were identified, including 30 esters, 9 alcohols, 9 aldehydes, 7 acids, 4 ketones, 3 volatile phenols and 1 miscellaneous compound. The major compounds in Chinese rice wine were ethanol, isoamyl formate, ethyl acetate, diethyl succinate, phenylethyl alcohol, benzaldehyde, ethyl lactate, 2-butanol and ethyl butyrate. Principal component analysis (PCA) and cluster analysis (CA) were used to characterize the different Chinese rice wine samples by geographic origin and wine age. The PCA results showed that the characterization of Chinese rice wine by SBSE-TD-GC-MS was highly related to geographic origin and wine age. The CA results indicated that geographic origin had more of an effect than wine age on the character of Chinese rice wine, and that 5-year old wines had a transition of flavor. The results showed that SBSE-TD-GC-MS together with chemometric methods could provide a practical reference for the characterization of Chinese rice wines.
  • Yoshinobu Katoh, Miyuki Katoh, Masashi Omori
    2015 Volume 21 Issue 3 Pages 381-389
    Published: 2015
    Released: September 10, 2015
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    Nucleotide sequences of the ribulose 1,5-bisphosphate carboxylase large-subunit (rbcL) in chloroplast (cp) DNA and 18S ribosomal RNA encoded in nuclear DNA (nuclear-encoded 18S-rRNA) were determined to clarify genetic diversity among cultivated teas. The nucleotide sequence alignment of rbcL in cpDNA enabled the taxonomic distinction of the section Thea. On the basis of these data, the rbcL nucleotide sequences of 195 cultivated teas in the Asian region were classified. The cultivated teas are separated into five groups: CSs type (var. sinensis), CSa type (var. assamica), type CSaa (like var. assamica), CIt type of C. irrawadiensis, and CTa type of C. taliensis. All the cultivated teas from the East Asia (China, Korea, and Japan) region were of the CSs type, whereas the cultivated teas from Bangladesh, Laos, Sri Lanka and Thailand were CSa type. The cultivated teas from India were separated into CSs and CSa types. The rbcL nucleotide sequences of the teas currently cultivated in Yunnan, China were CSa and CIt types, and the teas of Vietnam were CSa, CSs and CIt types. On the other hand, the teas cultivated in Myanmar included all types of CSs, CSa, CSaa, CIt and CTa. In addition, differences in nucleotide sequences were observed at three positions in 870 nuclear-encoded 18S-rRNA nucleotide sequences. The different nucleotide sequences of nuclear-encoded 18S-rRNA distinguished C. sinensis (var. sinensis and var. assamica) from wild tea species. Similarly, almost all cultivars tested were divided into the Cs type of C. sinensis (var. sinensis and var. assamica) and Cw type of wild tea species by alignment of nuclear-encoded 18S-rRNA nucleotide sequences, with an interspecific hybrid between C. sinensis and C. taliensis identified in a region of Myanmar. Analysis of genetic relationships indicated that many teas cultivated in the Myanmar region differ from the tea groups of East and South Asia. Our data indicated that the endemically cultivated teas in parts of Myanmar are conservationally important as new sources of desirable teas for future breeding programs and improvement of tea products.
  • Fatemeh Aboulfazli, Ahmad Salihin Baba
    2015 Volume 21 Issue 3 Pages 391-397
    Published: 2015
    Released: September 10, 2015
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    The effect of the type of milk on in vitro gastrointestinal survival of probiotics (Bifidobacterium animalis subsp. lactis Bb-12 and Lactobacillus acidophilus La-05) and organoleptic properties of ice creams were evaluated using ice creams made with cow, soy, coconut, and composite (cow or coconut with soy) milks. Soy milk was found to significantly improve the acid and bile tolerance of the probiotics but it decreased the total acceptability of ice cream. The probiotics in ice creams containing composite milk with cow's milk had higher total acceptability and were more protected against gastrointestinal conditions than ice creams containing coconut milk. The survival of Bb-12 was also better than La-05 in these conditions. In general, the presence of soy milk in ice creams resulted in a substantial improvement in probiotic tolerance to gastrointestinal conditions.
  • Shiro Takeda, Masahiko Takeshita, Tastuya Matsusaki, Yukiharu Kikuchi, ...
    2015 Volume 21 Issue 3 Pages 399-406
    Published: 2015
    Released: September 10, 2015
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    Helicobacter (H.) pylori is known to be a bacterial risk factor for gastric cancer. In this study, 16 strains of lactic acid bacteria (LAB) isolated from Mongolian dairy products were screened for potential probiotic activity against H. pylori strain no. 130 in vitro. Lactobacillus (L.) paracasei 06TCa19 and L. plantarum 07MR044 were identified as LAB strains with anti-H. pylori activities. Compared to strain 07MR044, strain 06TCa19 was more potent in reducing H. pylori counts in co-culture. The ability of strain 06TCa19 to inhibit the growth of H. pylori was attributable to its rapid and excessive generation of lactic acid. Moreover, oral administration of strain 06TCa19 was found to significantly reduce the number of colonizing H. pylori in the stomach of H. pylori strain no. 130-infected mice. Thus, strain 06TCa19 is potentially effective against H. pylori infection.
  • Hideki Masuda, So Hironaka, Yoko Matsui, Saori Hirooka, Mami Hirai, Yu ...
    2015 Volume 21 Issue 3 Pages 407-418
    Published: 2015
    Released: September 10, 2015
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    The purpose of this study was to compare the antioxidative activity of 68 culinary herbs and spices, and to evaluate the hepatoprotective effects of highly antioxidative plants (selected after an in vitro study) on carbon tetrachloride-induced oxidative stress in rats. Six Lamiaceae plants (oregano, common thyme, peppermint, lemon balm, sweet marjoram and rosemary) were found to be among the top 10 plants showing high total oxygen radical absorbance capacity (T-ORAC: sum of hydrophilic and lipophilic ORAC (H- and L-ORAC)). Their T-ORACs were composed of > 90% H-ORACs. Next, we prepared hydrophilic fractions of three selected Lamiaceae plants (peppermint, lemon balm and rosemary), in which bitterness and lipophilic odorants were reduced. Oral administration of these fractions in rats decreased aspartate aminotransferase and alanine aminotransferase activities in serum, inhibited lipid peroxidation, and restored superoxide dismutase and glutathione S-transferase activities in carbon tetrachloride-treated rats. Antioxidants in plants could exert a hepatoprotective effect by scavenging free radicals.
  • Ji Wang, Zhe Zheng, Xiao Zhao, Yawei Yang, Zhennai Yang
    2015 Volume 21 Issue 3 Pages 419-430
    Published: 2015
    Released: September 10, 2015
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    Three batches of yak milk cheese were made using lactococcal culture (L culture) (Batch L), sour yak milk culture (S culture) (Batch S), as well as the mixed L and S cultures (1:1) (LS culture) (Batch LS). The effects of these starter cultures on cheese ripening (90 d) properties, including proteolysis, texture, and volatile production, as well as the sensory characteristics of cheese were evaluated. The results showed that cheese composition was not significantly affected by the different cultures. Batch S and LS cheeses had higher proteolytic activity with a softer and less chewy structure than Batch L cheese. More volatile compounds were detected in Batch LS cheese than in the other two batches and the former was the only one to contain decanoic acid, 2-ethyl-1-hexanol, ethylbenzene, and styrene. However, 4-methylphenol with cowy aroma, which was observed in Batches L and S cheeses, was not detected in Batch LS cheese. Bacterial identification of S culture revealed a complex microbial composition, including 22 different strains from seven lactic acid bacterial species. The presence of several proteolytic and autolytic strains (Enterococcus durans etc.) in S culture might be important in the proteolytic activity, formation of texture, and characteristic volatiles of yak milk cheeses. In the sensory evaluation, Batch LS cheese was the most acceptable with the highest scores among the three batches. The results of this study suggested that a combination of commonly used lactococcal culture with traditional sour yak milk culture may be suitable for producing yak milk cheese with good acceptability.
  • Motokazu Nakayama, Daisuke Tomiyama, Keisuke Ikeda, Mao Katsuki, Ai No ...
    2015 Volume 21 Issue 3 Pages 431-437
    Published: 2015
    Released: September 10, 2015
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    Fatty acid esters are food additives with strong antibacterial activity against spore-forming bacteria. The antibacterial activity of monoglycerol fatty acid esters (MGs) and sucrose fatty acid esters (SEs) with various fatty acid chain lengths was systematically investigated on four typical Bacillus species: B. cereus, B. subtilis, B. megaterium, and B. coagulans. Monoglycerol monolaurate (MG12) and monoglycerol monomyristate (MG14) showed relatively strong bactericidal effects on vegetative cells of these species among the MGs tested at both pH 6.0 and pH 8.0. Different SEs showed bactericidal effects on different species at pH 6.0, while the SEs had antibacterial effects only on B. coagulans at pH 8.0. SEs showed antibacterial effects on vegetative cells of these species, as was the case with MGs. In addition, it was found that MGs and SEs showed strong antibacterial effects on both B. cereus and B. subtilis in the logarithmic phase of growth, while the antibacterial activities of MGs persisted longer than those of SEs.
  • Makoto Shimoyamada, Yuki Itabashi, Izumi Sugimoto, Makoto Kanauchi, Mi ...
    2015 Volume 21 Issue 3 Pages 439-444
    Published: 2015
    Released: September 10, 2015
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    Soymilk was prepared by ohmic heating. Heating time decreased as the applied voltage was increased. Precipitation, viscosity and surface hydrophobicity of protein in the soymilk were increased with the decrease in voltage applied. Voltages of 50 and 100 V resulted in a higher heating rate and consequent formation of a larger amount of protein particles (soluble aggregates), ranging from 40 to 120 nm in size, than the other conditions. Furthermore, soymilk prepared by ohmic heating at 50 or 100 V was converted into firmer tofu curd than that at 30 V. Ohmic heating at 30 V was thought to form larger protein particles than that at 50 and 100 V, and the resultant larger sized aggregates are considered to result in inferior tofu curd texture.
  • Ryosuke Miyabe, Yuto Takahashi, Hiroshi Matsufuji, Jun Ogihara, Kentar ...
    2015 Volume 21 Issue 3 Pages 445-451
    Published: 2015
    Released: September 10, 2015
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    An X-prolyl-dipeptidyl aminopeptidase has been purified from Lactobacillus gasseri by lysozyme treatment and seven chromatographic steps. The yield was 1.4% and the specific activity increased 265-fold over the crude enzyme extract. SDS-PAGE provided a single band with a MW of approximately 82 kDa. Gel filtration chromatography showed that the native enzyme was approximately 173 kDa, suggesting that the protein is a dimer. The amino acid sequences of the peptide fragments obtained after tryptic treatment of the purified enzyme were determined and found to be consistent with that of an X-prolyl-dipeptidyl aminopeptidase from L. gasseri ATCC 33323 (LGAS_0712, coverage: 31.74%). Optimal activity was observed at pH 7.0 and 55°C. The activity was inhibited by diisopropylfluorophosphate and phenylmethylsulfonylfluoride, and by divalent cations (Cu2+, Hg2+, and Zn2+). From these inhibition characteristics, the enzyme is likely a serine proteinase. Beta-casomorphin 7 (BCM-7, Tyr-Pro-Phe-Pro-Gly-Pro-Ile) was hydrolyzed into X-proline fragments from the N-terminus of the peptide. The characteristics of the enzyme are very similar to those of the enzyme from Lactobacillus sakei. However, as free amino acids were detected among the degradation products of BCM-7, some aspects of substrate specificity require further clarification.
  • Jin Kawamura, Emi Miura, Ken Kawakishi, Tsutomu Kitamura, Yae Morinaga ...
    2015 Volume 21 Issue 3 Pages 453-462
    Published: 2015
    Released: September 10, 2015
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    In order to utilize Apios americana flower as a functional food material, its safety and antihyperglycemic effects were investigated in mice. Normal mice fed dried A. americana flower or its methanolic extract (AFE) for 4 weeks did not show abnormalities in growth or plasma biochemistry profiles. However, ingestion of AFE lowered plasma glucose levels in ICR and diabetic KK-Ay mice. AFS60, fractionated from AFE by Sephadex LH-20 column chromatography, inhibited maltase; and suppressed the elevation of plasma glucose levels by 15% compared with control after oral administration of maltose in KK-Ay mice. Caffeoyl β-d-glucopyranoside was identified as the strongest maltase inhibitor in AFS60. While further toxicological studies are required, these results suggest that A. americana flower has maltase inhibitory activity and antihyperglycemic effects, and is a safe and useful novel food material for the prevention of diabetes.
  • Fei Peng, Caihong Cheng, Ying Xie, Yuedong Yang
    2015 Volume 21 Issue 3 Pages 463-471
    Published: 2015
    Released: September 10, 2015
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    Response surface methodology was used to optimize the microwave-assisted extraction process of phenolic compounds from Anli pear. Under the optimized conditions, antioxidant activities of phenolics from Anli pear were evaluated in vitro by scavenging capabilities of DPPH radical and the composition of phenolic compounds was performed by LC-MS. The optimal microwave-assisted extraction processing parameters were extraction time 124 s, microwave power 408 W, ethanol concentration 56% (v/v), and solvent/solid ratio 45:1, with an extraction yield of 9.801 mgGAE/gdm. The total phenolics have significant antioxidant activities, which can be used as a source of potential antioxidant. LC-MS analysis revealed that the phenolic compounds in the extract of Anli pear were mainly catechin, chlorogenic acid, quercetin glycosides, and isorhamnetin glycosides.
  • Tasuku Ogita, Jun Watanabe, Manabu Wakagi, Kouji Nakamichi, Seiichi Ko ...
    2015 Volume 21 Issue 3 Pages 473-477
    Published: 2015
    Released: September 10, 2015
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    Soy isoflavones are generally analyzed in accordance with the official method of AOAC International (OMA) 2001.10 and OMA 2008.03. However, this method is time-consuming and requires a large amount of sample. Therefore, the development of a better analytical method for soy isoflavones is required. In this study, OMA 2001.10 and OMA 2008.03 were improved to develop a quantification method for soy isoflavones. As a result, we shortened the analysis time using HPLC. The isoflavone content of a soybean sample was measured according to the improved method in triplicate, and the measurements were repeated on three different days. Both the repeatability and intermediate precision (within laboratory) for the quantification of the isoflavone content (aglycone) of the soy sample were good. The recovery of isoflavones spiked into a soy sample at two different concentrations ranged from 94% to 105%. The multilaboratory validation study with 7 participating laboratories showed satisfactory interlaboratory precision; all HorRat values were < 2.
  • Shiori Idogawa, Tomoyuki Fujii
    2015 Volume 21 Issue 3 Pages 479-487
    Published: 2015
    Released: September 10, 2015
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    The applicability of Einstein's and Krieger-Dougherty's theories of viscosity was examined using soymilk. Under dilute conditions, the relative viscosity of the emulsion with suspended oil bodies was proportional to the volume fraction of oil bodies, and the slope increased to greater than 2.5. Under concentrated conditions, the oil body suspension showed a Krieger-Dougherty-like dependency on volume fraction. The oil bodies in soymilk behaved as suspended substances and it was possible for us to predict the relative viscosity from the volume fraction of oil bodies. We also focused on the coagulation of soymilk by magnesium chloride and examined the validity of the novel viscous model, combining the extended Einstein equation and the Krieger-Dougherty equation, on the effect of cross-linkers. At 10°C and 25°C, the equation could be applied to various soymilk samples. In addition, the viscosity during coagulation could be predicted when the parameter hc of the dispersion system was utilized.
  • Tomoya Nagano, Kaori Hayashibara, Manabu Ueda-Wakagi, Yoko Yamashita, ...
    2015 Volume 21 Issue 3 Pages 489-494
    Published: 2015
    Released: September 10, 2015
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    We previously reported that the intake of black tea promotes translocation of the insulin-sensitive glucose transporter (GLUT) 4 in skeletal muscle. In this study, we investigated whether black tea polyphenols (BTP) promote GLUT4 translocation in L6 myotubes. BTP promoted glucose uptake accompanied by GLUT4 translocation in L6 myotubes. As the molecular mechanism, BTP induced the phosphorylation of insulin receptor substrate-1, atypical protein kinase C, Akt Thr308, Akt substrate 160, and AMP-activated protein kinase (AMPK), but did not affect that of Akt Ser473. BTP increased glycogen accumulation through inactivation of glycogen synthase kinase 3β (GSK-3β). Theaflavin, one of the major components in black tea, also promoted the glucose uptake accompanied by GLUT4 translocation observed with BTP in L6 myotubes. These results indicate that BTP activates both PI3K- and AMPK-dependent pathways to promote GLUT4 translocation and glycogen accumulation in skeletal muscle cells. Moreover, theaflavin is one of the active components in BTP.
Notes
  • Tomonori Unno
    2015 Volume 21 Issue 3 Pages 495-498
    Published: 2015
    Released: September 10, 2015
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    Maple syrups are prepared by thermally concentrating maple sap. Based on their clarity, density and characteristic taste, they are divided into 5 grades: extralight, light, medium, amber and dark. This study aimed to evaluate differences in antioxidant activities among grades by the hydrophilic oxygen radical absorbance capacity (H-ORAC) method. The results demonstrated that H-ORAC values varied widely depending on the degree of brown coloration; darker-colored maple syrups showed stronger antioxidant activity. The darker-colored grades of maple syrup also contained more reducing sugars (fructose and glucose) than the lighter-colored ones; however, the grade had little impact on the content of free amino nitrogen in the syrup samples. The present study suggests that the brown pigments (melanoidins) produced by condensation of amines and reducing groups may contribute significantly to the antioxidant activity of maple syrups.
  • Takahisa Shiraki, Takashi Kometani, Kayo Yoshitani, Hiroki Takata, Tak ...
    2015 Volume 21 Issue 3 Pages 499-502
    Published: 2015
    Released: September 10, 2015
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    Highly branched cyclic dextrin (HBCD) is a novel type of maltodextrin with a narrow molecular weight distribution that is produced from starch. In this study, we investigated the effects of HBCD administration on endurance performance. Seven elite swimmers participated in three trials, conducted in random order. In each trial, the subjects received either HBCD, glucose (1.5 g carbohydrate/kg body weight) or water (as a control), and immediately carried out 10 cycles of intermittent swimming consisting of 5 min of swimming at 75% followed by 3 min of rest, and subsequent swimming at 90% to exhaustion. The time to fatigue was about 70% longer in the HBCD trial than that in the glucose and control trials, a significant difference. Plasma glucose in the HBCD group was maintained at higher levels during pre-swimming cycles than that in the glucose or water group. These results suggest that HBCD administration enhances endurance performance.
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