Miki Yoshimura

For the purpose of promoting the utilization of venison as a functional food, we investigated the carnitine content in cooked venison. The present work aimed to quantitate free carnitine and acylcarnitine in cooked venison using liquid chromatography-tandem mass spectrometry [LC-MS/MS]. As a result of heat treatment, hydrophilic L-carnitine showed a tendency to decrease, and hydrophobic acylcarnitine showed a tendency to increase, except under frying. However, only the acetylcarnitine showed a tendency to decrease because it is a low molecular weight compound that is connected to a two-carbon fatty acid. We propose that steaming is the most effective of the heat treatment methods tested in the present work for promoting the utilization of venison as a functional food.

We examined the physical properties of Japanese white salted noodles consisting of 0, 6, 10 and 15% esterified tapioca starch and boiled for 13 mm, as well as their palatability and mastication properties in both the young (22.5 +/- 3.0 years) and the elderly (77.1 +/- 7.5 years). Noodles consisting of 6, 10, and 15% esterified tapioca starch had higher moisture content, as well as softer and less elastic texture than the 0% sample. Specifically, the 10% sample was perceived as softer, easier to eat, and smoother than the 0% sample by both the young and the elderly. This was likely due to the large voids among starch particles, high starch particle water absorption, and ease of gelatinization in the dried noodles. However, the sample properties did not vary the masticatory function of the masseter and suprahyoid muscles. A comparison between the young and the elderly regarding food palatability and mastication revealed that the weak masticatory strength in the elderly limited the preference for hardness in foods. Furthermore, decreased swallowing was observed in the elderly as a result of the weakened suprahyoid musculature.

For the purpose of promoting the utilization of venison as a functional food, we investigated the carnitine content and physical properties of venison subjected to different sous-vide (cooking by steam heating under vacuum) processing temperatures. The present work aimed to quantify free carnitine and acylcamitine using liquid chromatography-tandem mass spectrometry. Compared to meat samples heated at 100 degrees C, those heated at 80 degrees C showed a slow temperature increase and a low rate of weight loss. Moreover, heating at 80 degrees C resulted in greater hydrophilic L-carnitine and low molecular weight acetylcarnitine than heating at 100 degrees C. On the other hand, levels of hydrophobic hexanoylcarnitine, myristoylcarnitine, and palmitoylcarnitine were greater at 100 degrees C. Determinations of physical properties showed that samples heated at 80 degrees C were significantly tenderer than those heated at 100 degrees C. Furthermore, sensory evaluation results showed that samples heated at 80 degrees C scored highly in the following three attributes : toughness (palatability); umami; and overall palatability. Based on these results, we propose that heating at 80 degrees C is more desirable with respect to functionality and palatability for promoting the utilization of venison as a functional food.

食物繊維の物理的性状は、固体状、水に溶けて粘性を示すもの、ゲル状などさまざまであり、その咀嚼・嚥下は、ライフステージごとに異なっている。新生児期は乳汁などの液体中心であるが、乳児期は離乳食を通し、液体から徐々に穀類、芋類などを軟らかくした固形物を摂取できるようになり、食物繊維を摂取するようになる。幼児期および学童期になると、食物繊維を多く含む硬い食品をしっかり噛んで食べることによって、咀嚼機能が向上する。成人期は、食物繊維をしっかり咀嚼することによる健康への効果が多く見られる。高齢期は、咀嚼・嚥下機能が低下し、硬い食品が食べにくくなるので、調理・加工の工夫により食物繊維を軟らかくし摂取していく必要がある。また、嚥下困難になると、水溶性食物繊維がもつ粘性を利用して、飲み込みやすくするなどの工夫が不可欠となる。このようにヒトのライフステージごとの咀嚼・嚥下に、食物繊維のもつ物理的性状の幅広さは多様な影響を与えている。(著者抄録)

野生シカ肉の有効活用を目的として、オスジカ、メスジカの肉重量および栄養成分の差異について検討した。試料は、兵庫県丹波地域において2010年9月、11月、12月に捕獲したニホンジカを使用した。オスジカの平均体重は46.4kg、肉重量は16.7kg、歩留率は35.6%、栄養成分は100gあたりタンパク質21.2g、脂質0.4gを示した。メスジカの平均体重は36.3kg、肉重量は13.1kg、歩留率は35.7%、タンパク質20.5g、脂質0.7gを示した。メスジカは、オスジカより小さいが、肉の歩留率は同等で、脂質量は増加傾向にあった。オスジカ、メスジカとも捕獲月による肉重量および栄養成分値の差異は小さかった。肉の部位別では、オスジカ、メスジカともモモとスネの重量割合が高く、肉の部位間での栄養的特徴の違いは小さかった。(著者抄録)

Nine kinds of glutinous rice flour were prepared by wet disk milling under various clearances (20, 40, 60 mu m) and rotational speeds (400, 600, 800 rpm). The glutinous rice flour samples showed a mean volume diameter of 4.8-12.1, span ([d90-d10]/d50) of 1.5-3.5, and various particle forms, while macronutrients and damaged starch were almost identical. The most suitable clearance and rotational speed were empirically chosen for controlling the viscoelasticity of the dispersion paste. Under these empirical conditions, starch particle size distribution was narrow, particles were dispersed, and dynamic viscoelasticity of the dispersion paste decreased with decreasing starch concentration. The relationship between the quantity of glutinous rice flour used and the viscoelasticity of the dispersion paste indicated that glutinous rice flour prepared empirically was the most suitable method for controlling viscoelasticity.

The genome sequencing of Aspergillus oryzae completed in 2005 predicted eight genes of glutamate decarboxylase (GAD) isoforms. A detailed amino acid-sequence analysis of those GAD isoforms and gene expression study were performed. The homology of eight A. oryzae GAD isoforms was compared with those of other species. The isoforms could be divided into four groups based on identities of their amino acid sequences. Two of the isoforms had 31% homology with human GAD 65; two of the isoforms had 55 and 58% homology with rice GAD 1, respectively; two of the isoforms had 45 and 48% homology with yeast (Pichia stipites), respectively; two of the isoforms were unidentified. RT-PCR analysis showed that eight GAD genes were expressed in A. oryzae cultured in the rice solid medium, while four GAD genes were expressed in A. oryzae cultured in the yeast liquid medium. The presence of the eight genes for GAD isoforms in A. oryzae suggests that GADs must be utilized for specific purposes, which should be explored in future studies.

シカの食品としての有効活用のため、タンパク質分解酵素を有する多穀麹(雑穀に麹菌で発酵させた素材)を添加調理したシカ肉加工品の物性と嗜好性について検討した。熟成前と熟成後のシカ肉に、多穀麹を0〜5%添加し10℃で2日間保蔵後、加熱調理し試料とし、肉汁量測定、破断測定、アミノ酸分析から検討した。多穀麹添加により、シカ肉加工品の肉汁放出量は減少し、軟らかく、総アミノ酸含量が増した。また、官能評価により、軟らかく、うま味があり、飲み込みやすいと判断された。シカ肉は鉄分を多く含み、多穀麹で熟成させたハムなどの加工食品にすることで、若年者の鉄欠乏性貧血予防や高齢者の低栄養予防の食品としての可能性が見出された。(著者抄録)

The effects of the concentration and molecular weight (M-w) of collagen-peptide (CP) from tilapia scales on the rheological and thermal properties of agar gel (AG) were examined by gel permeation chromatography, dynamic viscoelasticity, rupture properties, syneresis and differential scanning calorimetry. Three kinds of CP from tilapia scales (CP1000, CP5000 and CP10000) with M-w = 7.4 x 10(2), 4.5 x 10(3) and 1.0 x 10(4), respectively, were investigated. The results showed that CP1000 had the highest rupture stress, Young's modulus and syneresis of the AGs tested. For CP5000 and CP10000, rupture stress and Young's modulus were lower, syneresis was repressed and enthalpy was decreased. Therefore, it was suggested that higher molecular weight CP hindered cross-linking formation in AGs. Also, a comparison of CP from porcine skin and tilapia scales suggested that viscosity and enthalpy of CP solutions and gel strength were influenced by molecular weight and amino acids composition.

We examined whether Japanese white salted noodles mixed with 6% esterified tapioca starch would be a suitable food for the elderly. Samples studied were noodles prepared with wheat flour which had been boiled for 10 min (MG10), and noodles with wheat flour that was partly mixed with tapioca starch and boiled for 10 or 13 min (CA10 and CA13, respectively). Physical properties of the food were assessed by moisture content, shape change. and penetration tests. Mastication was evaluated by electromyography while young (age, 23.3 +/- 2.7 years) and elderly (age, 75.8 +/- 7.3 years) subjects ate the same samples, and palatability was assessed by sensory evaluation. Results revealed the following: 1) CA10 and CA13 were found to have a smoother, softer, and more elastic texture than MG10, and were considered by all subjects to be easier to eat and more palatable. 2) CA13 had a higher moisture content than CA 10. It was softer, less elastic, and easier to chew in the early stage of mastication, and was considered to be the easiest to eat. 3) Mastication and palatability differed between young and elderly subjects. Elderly subjects chewed samples for a longer period of time and considered CA13 to be the easiest to eat with the best palatability. The young subjects also considered CA13 to be the easiest to eat, but found CA10 to be the most palatable and very chewy due to its dense firmness. 4) CA13 was considered by the elderly subjects to be the easiest to eat, despite its chewy consistency. Therefore, CA13 is likely useful in preventing masticatory hypofunction as it is a suitable food for the elderly. (Received Dec. 14, 2011 : Accepted Mar. 3, 2012)

Carnitines exist as either free carnitine or acylcarnitine bound to a fatty acid. However, most of the acylated forms are found only in minuscule amounts, and thus not easy to separate, detect and quantify. Therefore, the purpose of the present study was to determine the quantity of free carnitine and acylcarnitine in venison (round primal cut) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Free carnitine and four acylcarnitines (acetylcarnitine, hexanoylcarnitine, myristoylcarnitine and palmitoylcarnitine) were detected. These results suggest that venison contains more free carnitine and acylcarnitines than beef, pork and chicken. (Received Jul. 2, 2012; Accepted Sep. 11, 2012)

The physical properties, sensory characteristics and power consumption were evaluated to elucidate the effect of steaming time on the thermal energy saving and palatability of noodles supplemented with cassava starch. Noodles supplemented with 6% cassava starch and noodles prepared w ith wheat flour were used.<br>Shortening the boiling time from 10 minutes to 3 minutes and then holding reduced the electrical energy consumption by 32% without any deterioration of palatability. Noodles supplemented with cassava starch that had been boiled for 3 minutes and then steamed for 6 minutes were evaluated as the best in respect of the gumminess. The steaming time more strongly affected the palatability of the noodles than the supplementation with cassava starch when comparing with the noodles prepared from wheat flour. The noodles supplemented with cassava starch became softer with increasing steaming time, whereas there was no further softening of the noodles prepared from wheat after halfway through the steaming period. The results show that steaming the noodles supplemented with cassava starch reduced the thermal energy required and that the texture depended on the steaming time.

Starches were isolated from five improved rice varieties developed by West African Rice Development Agency (WARDA) namely FARO 32, FARO 51, FARO 52, FARO 54 and NERICA. Starch yield and amylose content varied between 73.77-70.02% and 22.88-24.48% respectively. Starches were polyhedral in appearances and within the size range 1.5-6.1 mu m. The X-ray diffraction patterns of the starches show a peak centered on 2 theta = 5.1 degrees, a doublet on 17.1 degrees and 18.1 degrees, and another single peak at 23.12 degrees. However, NERICA shows no doublet but a single peak at 2 theta = 17.1 degrees with a small shoulder. The peak viscosity of the starches ranged between 147.48 and 209.17 RVA corresponding to FARO 52 and NERICA respectively. A neat distinction is observed between the marked shear thinning of FARO 52 and the apparently plastic behavior of the other samples. Important differences appear in the low shear region where the viscosity increases in the following order: FARO 52 < FARO 54 < FARO 51 < FARO 32 < NERICA. The mechanical spectra exhibit similar profiles as the storage modulus (G') prevails over the viscous component (G '') and is weakly dependent on the frequency. However, the storage modulus increases in the same order observed for low shear viscosity. The percentage retrogradation was between 61.9 and 86.6% and NERICA starch showed the least retrogradation indication. NERICA starch exhibited highest swelling and solubility, while the least was observed in FARO 52. Rheology and functional properties are dependent of amylose composition. This study provides knowledge for the utilization of starches isolated from improved rice varieties that would be relevant for both domestic and industrial applications. (C) 2011 Elsevier Ltd. All rights reserved.

Hydrogels were prepared by the cross-linking reactions of carboxymethyl cellulose with di- or polyfunctional glycidyl ether to investigate the effects of different cross-linker's chain length and the number of epoxy groups on the properties of the gels. Fourier transform infrared spectra showed a new peak at nu=1,740 cm(-1) assigned to the absorption of carbonyl groups in the new ester structure formed by the cross-linking of -COONa with the epoxy compounds. The interior morphology data indicated microporous network structures which correlated with the swelling of hydrogels. The swelling data in water, urea, sucrose, urine and aspartame showed increases in swelling with an increase in chain length of the cross-linker but decreased with the number of epoxy groups on the cross-linker. Collectively, the gels were ionic strength sensitive. The rheology experiments showed that gel point (t(gel)) increased with the chain length of the cross-linker but reduced with increase in number of epoxy groups on the cross-linker. Dynamic oscillatory measurements indicated stronger material functions in gels prepared with polyfunctional epoxy cross-linkers. The hydrogels prepared with difunctional epoxy groups had higher loading capacity and faster release of bovine serum albumin compared with hydrogels based on polyfunctional epoxy group cross-linkers.

The effect of the stereoregularity and molecular weight of poly(vinyl alcohol) (PVA) on the mechanical properties of hydrogel was investigated. Compressive strength, creep behavior, and dynamic viscoelasticity were measured on hydrogels of syndiotacticity-rich PVA derived from poly(vinyl pivalate) (D-p = 1690 diad-syndiotacticity = 61%, D-p = 8020 diad-syndiotacticity 62%) and atactic PVA (D-p = 1750 diad-syndiotacticity 54%, D-p = 7780 diad-syndiotacticity = 54%). Increasing the molecular weight of molecular chains constituting the gel improved the compressive strength of atactic PVA hydrogel. The stereoregularity of PVA had a greater effect than molecular weight on the strength of the hydrogel. Gel prepared from 8.8 g/dL syndiotacticity-rich PVA had a high compressive modulus of 10 kPa, and the compressive modulus of the gel prepared from 3.3 g/dL was comparable with that of atactic PVA hydrogel prepared with more than 6 g/dL. The dynamic storage modulus of the gel derived from syndiotacticity-rich PVA was remarkably higher than that of the atactic PVA gel and remained constant up to 60 degrees C. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 573-578, 2011

Since collagen-peptide (CP) is composed of peptide chains and fragments with different molecular weights, the rheological and thermal properties of CP must depend on not only amino acid composition but also molecular weight (M-w). Therefore, in the present study, we investigated the effects of the molecular weight of added CP on agar gels using four kinds of CP from porcine skin with M-w = 1.1 X 10(3), 1.9 X 10(3), 5.4 X 10(3) and 1.0 X 10(4) (CP1000, CP2000, CP5000 and CP10000, respectively). Measurement methods included gel permeation chromatography [GPC], dynamic viscoelastic measurement, rupture properties, syneresis, liquid chromatography mass spectrometry [LC/MS] and differential scanning calorimetry [DSC]. Results showed that for CP1000, rupture stress and Young's modulus increased slightly, and syneresis was inhibited at high density. Since the results of CP2000 differed from CP1000 for rupture properties, it was suggested that ingredients with higher molecular weight influenced rheological and thermal properties of agar gels. On the other hand, it was suggested that ingredients with low molecular weight influenced syneresis, since the results of CP2000 were similar to CP1000. Because the results for CP5000 and CP10000 significantly differed from those for CP1000 and CP2000, it was suggested that ingredients with higher molecular weight influenced agar gels and their ingredients hindered the cross-linking formation. (Received Sep. 24, 2010; Accepted Dec. 19, 2010)

Grain koji was added to sika deer meat and the physical properties and the palatability of the cooked deer meat were examined for effective use of the venison. Japanese sika deer captured in Hyogo Prefecture were used. Grain koji is an enzyme-rich food that is produced by solid-state fermentation with AsPergillus oryzae and a mixture of six kinds of grain. The meat, before and after ripening, was minced, and grain koji was added at 0%, 1%, 2.5%, and 5%. For comparison, grain without koji was added to sika meat at 5% and mixed. The meat was formed into a column (1 cm h x 4 cm d) and then preserved for two days at 10 degrees C. It was vacuum packed, and steamed at 100 degrees C for 20 minutes. The sample volume increased with increasing grain koji, syneresis, rupture stress and rupture energy were markedly reduced, while the total free amino acid levels increased. The sensory panel judged that the sika deer product with grain koji was savory, soft, and easy to swallow. (Received Apr. 8,2011: Accepted Aug. 3. 2011)

Grain koji was added to sika deer meat and the physical properties and the palatability of the cooked deer meat were examined for effective use of the venison. Japanese sika deer captured in Hyogo Prefecture were used. Grain koji is an enzyme-rich food that is produced by solid-state fermentation with AsPergillus oryzae and a mixture of six kinds of grain. The meat, before and after ripening, was minced, and grain koji was added at 0%, 1%, 2.5%, and 5%. For comparison, grain without koji was added to sika meat at 5% and mixed. The meat was formed into a column (1 cm h x 4 cm d) and then preserved for two days at 10 degrees C. It was vacuum packed, and steamed at 100 degrees C for 20 minutes. The sample volume increased with increasing grain koji, syneresis, rupture stress and rupture energy were markedly reduced, while the total free amino acid levels increased. The sensory panel judged that the sika deer product with grain koji was savory, soft, and easy to swallow. (Received Apr. 8,2011: Accepted Aug. 3. 2011)

The effects of the concentration and heating temperature of collagen-peptide from pig skin (CP) on the mechanical and thermal properties of agar gel (AG) were studied by measuring the rupture properties, dynamic viscoelasticity, and differential scanning calorimetry (DSC). The frequency dependence of <i>G′</i> and <i>G″</i> of a 50 w/w% CP solution showed that it behaved as a liquid even when cooled to 10°C. The rupture strain, stress and storage modulus of the AG-CP gel decreased with increasing CP concentration >20 w/w%. AG (5 w/w%) showed an endothermic peak at 78.8°C by heating DSC, and an exothermic peak at 32.5°C by cooling DSC. A solution of CP (30 w/w%) showed an endothermic peak at 20.2°C and an exothermic peak at 10.0°C. Mixtures of AG (5 w/w%) and CP (10~40 w/w%) showed two endothermic peaks, while AG (5 w/w%) and CP (50 w/w%) showed one endothermic peak. It is suggested that CP inhibited the gelation of AG. The molecular weight of CP was unchanged by heating at 60°C and 90°C, although the storage modulus and rupture strain of the AG-CP gel at 90°C were a little larger than the values 60°C.

キサンタンガム(Xと表す)にジェランガム・ネイティブ型(Gと表す)を加えた0.6wt%トロミ剤(X:G=0.6:0.0、0.4:0.2、0.2:0.4、0.0:0.6)のレオロジー的特性について、流動特性、動的粘弾性およびテクスチャー特性により検討した。トロミ剤は、ずり流動化流動であり構造のある液体のような挙動を示した。ジェランガムの混合比率が高いほうが、弾性要素が高く、付着性が増した。ジェランガム単独系(X:G=0.0:0.6)では弾性的なゲルに近い挙動を示した。また、トロミ剤(X:G=0.6:0.0、0.4:0.2、0.2:0.4)を添加したきざみ食の咀嚼性について、若年者パネル(平均年齢20.9±1.1歳)と高齢者パネル(平均年齢73.3±8.7歳)により検討した。きざみ食の咀嚼回数と咀嚼時間は混合比率による有意差が認められなかった。若年者パネルによる官能評価より、X:G=0.6:0.0のトロミ剤を添加したきざみ食が、噛みやすく、飲み込みやすく、総合的に好ましいと評価された。また、若年者パネルではX:G=0.6:0.0の咀嚼周期が小さかった。高齢者パネルによる官能評価では、X:G=0.2:0.4のトロミ剤を添加したきざみ食が、まとまりが良く、噛みやすく、飲み込みやすく、総合的に好ましいと評価された。また、高齢者パネルではX:G=0.2:0.4の咀嚼周期が小さかった。これらの結果より、キサンタンガム・ジェランガム混合系トロミ剤のレオロジー特性が高齢者にとってきざみ食を飲み込みやすくすることが示唆された。また、高齢者パネルの歯の状態が、きざみ食の咀嚼回数・咀嚼時間に影響を及ぼした。(著者抄録)

分離大豆タンパク質(SPI)のパンクレアチンによる分解に及ぼす食物繊維キシログルカンの影響を検討した。キシログルカンはパンクレアチンの添加では分解されず、貯蔵剛性率G'と損失剛性率G''の変化はなかった。しかし、SPIはパンクレアチンの作用で分解され、時間と共にG'とG''の値は減少し、パンクレアチンの濃度が高くなるに連れて分解作用は速くなった。キシログルカンが存在する時、SPIのパンクレアチンによる分解速度はキシログルカンの濃度上昇と共に遅くなった。更に、パンクレアチン添加前に同じG'を示す条件下では、低分子キシログルカンとの混合溶液の方が高分子キシログルカンとの混合溶液より分解を遅延させた。SPIとキシログルカンの混合系でのパンクレアチンの分解作用は、混合されるキシログルカンの濃度、及び分子量が異なるサンプルの混合量に影響されることが示された。

The concentration effect of collagen-peptide (CP, 0-30% w/v) on the physical properties of agar gel (AG, 1% w/v) was studied by measuring the rupture properties, textual properties, dynamic viscoelasticity, syneresis and differential scanning calorimetry (DSC). The rupture stress, rupture energy and hardness of AG gel were increased by adding sugar. The rupture stress, rupture energy and hardness of agar and collagen-peptide (AG-CP) gel were increased up to a certain CP concentration and the decreased with increasing CP concentration. CP and sugar prevented the syneresis of AG gel. A CP solution showed liquid behavior in the temperature range studied (5-30℃) in respect of the frequency dependence of G′and G″. AG showed an endothermic peak with heating DSC, while CP did not show any exothermic or endothermic peak in the temperature range studied (5-90℃). The rheological and DSC changes imply that an increase in the effective concentration of AG from the immobilization of water molecules by adding a certain CP concentration promoted the hardness of AG-CP gel. However, this hardness of AG-CP gel began to decrease with increasing CP concentration, because CP retarded that gelation of AG.

The effect of the concentration of soybean powder (11-17% (w/w)) on soybean curds prepared from powdered soybean in the presence of glucono-delta-lactone (GDL) were studied by rheological measurement (compression test and dvnamic viscoelastic measurement), measurement of amount of syneresis, observation of the network structure by confocal laser scanning microscopy (CLSM) and sensory evaluation of physical properties. Results of rheological measurements of soybean curd, indicated that the rupture strain, rupture stress, rupture energy, storage modulus and loss modulus increased with increasing concentration of soybean powder. In the protein concentration range of 4.4-6.9% (w/w), the storage modulus was proportional to 2.3 tH power of protein concentration. The degree of syneresis of this soybean curd decreased with increasing concentration of soybean powders. CLSM data indicate that the network structure of the curd increased concurrently with the concentration of Soybean powder. The network structure of the curd was well correlated with the results obtained from rheological measurements. As sensory evaluation indicated that the soybean curd with a higher concentration of soybean powder (15% (w/ w) or 17% (w/w)) was observed to be harder, less moist and fuller bodied, it was judged preferable to the soybean curd with lower concentration (11% (w/w)).

固有粘度の異なる4種のキサンタンガムを濃度一定(0.6wt%)とし,調味料入りキサンタンガム溶液の物性ときざみ食の嗜好性を若年者パネルにより検討した.高齢者パネルにより歯の状態別に食品摂取可能度を検討し,若年者パネルにより嗜好性の高い評価を得たキサンタンガムを用いて,ニンジンのきざみ食の形状を変えた場合の咀嚼性へ及ぼす影響などについて検討した.キサンタンガムのレオロジー特性が,ニンジンのきざみ食を飲み込みやすくすることが示唆された.しかし,噛みやすさの項目では,有歯顎者および部分義歯装着者はキサンタンガムを添加したきざみ食が噛みやすいと評価したが,総義歯装着者では角切りが一番噛みやすく,ニンジンのきざみ食では小さすぎて噛みにくいと評価した.歯の状態によっては,噛みやすさは試料の大きさにより異なる影響を受けることが示唆された

Gelation kinetics of powdered soybean dispersion in the presence of glucono-partial derivative-lactone (GDL) was studied by dynamic viscoelastic measurements and differential scanning calorimetry (DSC). The gelation time became shorter and the rate constant of gelation increased with increasing concentration of soybean powder (11similar to17%) and GDL (0.2similar to0.5%) or heating temperature (40similar to90degreesC). Both storage and loss moduli increased with increasing concentration of soybean powder and GDL. The storage modulus as a function of heating temperature showed a maximum at 70degreesC for heated dispersion of powdered soybean. A non-heated dispersion of powdered soybean showed two endothermic peaks, while a heated dispersion of powdered soybean did not show any endothermic and exothermic peak in the temperature range studied by heating DSC (20similar to140degreesC). The peak temperature for a non-heated dispersion of powdered soybean shifted to higher temperatures with increasing GDL concentration. From the rheological properties it is suggested that a heated dispersion of powdered soybean formed a stronger gel with increasing concentration of soybean powder and GDL..

増粘剤(12%キサンタンガム,グアーガム,ローカストビーンガム)のレオロジー的性質と増粘剤を付与したきざみ食(ニンジン,魚)の嗜好特性について,粘度,動的粘弾性及び官能評価より検討した.増粘剤を付与したきざみ食の咀嚼回数・咀嚼時間は,増粘剤を付与しないきざみ食に比べ減少した.高齢者は若年者より,試料の咀嚼回数・咀嚼時間は増大した.若年者による官能評価では,キサンタンガム,グアーガムを付与したきざみ食は,ローカストビーンガムを付与したきざみ食に比べ,粘りがあり,残留感が少なく,飲み込み易いと評価された.高齢者では,いずれの官能評価項目においても3種の増粘剤の有意差はみられなかった

寒天ゼリーの物性における惣菜添加の影響について,破断特性より検討した.惣菜の寒天寄せは寒天ゼリーより変形の少ない弱いゲルとなり,微小変形に対して抵抗のあるゲルとなった.若年者パネルの官能検査では,惣菜の寒天寄せは飲み込みやすく,飲み込んだ後も残留感が少ないとの結果を得た.しかし,見た目や風味が悪く,総合評価では良い評価を得ることができなかった.咀嚼が容易な高齢者パネルでは,「昆布豆の寒天寄せ」は「昆布豆」より軟らかいため飲み込みやすく,残留感も少ないが,その他の項目で有意差が認められなかった.一方,義歯や嚥下困難を含む咀嚼が困難な高齢者パネルでは,「昆布豆の寒天寄せ」は飲み込みやすく,残留感が少なく,総合評価でおいしいと評価された.咀嚼・嚥下困難な高齢者のための食事では食材を軟らかく煮て細かく刻み,ゲル化剤を使用してまとまりのある状態にすることによりおいしくなることが認められた

The Penetration depth of needles into potatoes heated under normal cooking conditions by which the gas supply was regulated to provide high heat, medium heat, and low heat by the control knob on a gas hob, was evaluate. A sensory evaluation of the cooked potatoes was also conducted. Measurements were taken of the heating time and gas consumption needed for the temperature of the water in an aluminium cooking pot (JIS standard) containing potatoes to rise from 20℃ to 100 ℃. Reproducibility of the heating rate, gas consumption and volume of residual water was confirmed. A dispersion analysis and Turkey's examination indicated a significant difference in penetration depth between high-heat cooking (10min.) and the other conditions. This result was confirmed by the sensory evaluation. We classified the parameters for the sensory evaluation into three categories by the time required for significant difference to become apparent.

The deacetylation and gelation of konjac glucomannan (KGM) following alkali addition was investigated by Fourier transform infrared, while the rheological properties of KGM with different molecular weights were studied by dynamic viscoelastic measurements in shear mode and penetration force tests. It was found that gelation occurred after significant deacetylation had taken place. Rheometrical studies revealed that KGM with different molecular weights exhibited different gelation characteristics in small amplitude oscillatory shear flow. For the samples of fractionated KGM with lower molecular weights, a decrease in both the storage shear modulus (G′) and loss shear modulus (G″) was observed during gelation at temperatures above 75°C. It is suggested that the decrease results from the wall slip between sample and measuring geometry owing to a rapid gelation process with syneresis and/or disentanglement of molecular chains adsorbed on the surface of parallel plates from those located in the bulk. Penetration force tests were employed to confirm the occurrence of slippage and thereby no decreases in rigidity of samples were observed during gelation. For the native KGM samples decreases in G′ and G″ during gelation were not observed, and it is suggested that this is due to the effect of the higher molecular weight and increased solution viscosity of these samples on the gelation kinetics. © 2001 John Wiley &amp Sons, Inc.

A molecular level description of the time course of the gelation of the polysaccharide konjac mannan (KM) is presented and the role of alkali addition is considered in detail. NMR relaxometry is utilized as a complementary methodology to mechanical spectroscopy in order to probe events occurring as a prelude to network formation, and high-resolution NMR is used to follow the deactetylation process. It is shown that the addition of alkali plays an important solubilizing role in addition to facilitating the deacetylation of the chain. Deacetylation is important both in reducing the inherent aqueous solubility of the polymer and in progressively negating the alkali-induced polyelectrolytic nature of the polysaccharide chain via reaction induced pH changes. It is proposed that observed induction periods following alkali addition (during which the elastic modulus does not rise) are not simply deacetylation delays but are related to the aggregation kinetics of the deacetylated material.