Hot air drying is conventionally applied for the production of dried fruit; however, hardening and browning of the fruit pulp surface often occurs during processing. We demonstrated that microwave irradiation of Japanese pear pulp or grape, followed by hot air drying, produced high quality semi-dried fruit. Dried Japanese pear produced using this method showed uniform softness and a vivid yellow-orange color. In the case of dried grape products, microwave irradiation pretreatment improved the retention of both skin color (yellow-green and red) and original flavor (such as muscat and foxy). In addition, microwave pretreatment shortened the subsequent hot air drying period by approximately 30% for Japanese pear and 60% for grape. This method could be applied to other fruits such as apple, pear and peach. Dissemination of the method has resulted in commercialization of some dried fruit and confectionary products. However, a system capable of mass production, resulting in reduced production costs, is needed to promote the practical use of this method.
POP/OPOから成る分子間化合物(MC)の結晶化に及ぼすショ糖脂肪酸エステル(SE)とモノパルミチン(MP)の添加効果を検証した.2種類の乳化剤の添加により,MCの形成は阻害されずに安定なβ型のMC結晶が成長した.この際,MPは不均一核形成によりMCの結晶化を促進するが,SEはMCの結晶核形成を抑制することが明らかとなった.さらに,SE添加では得られるMC結晶が微細化する傾向が認められた.本研究によって,乳化剤の脂肪酸組成,親水基を含む立体構造,親水/疎水バランス,添加濃度,冷却速度,油脂組成(液油量)および油脂への溶解度という多様な要因が,冷却過程におけるMCの結晶化の促進あるいは抑制の効果や,結晶形態に影響を及ぼすことが示された.
茹で調理における放射性セシウムの茹で湯への移行と麺の硬さとの関連性を検討するために,麺の硬さが異なる,グルテン含有率5%,10%,20%の米粉麺を用いて,放射性セシウム(137Cs)および無機元素類の加工係数Pfと残存割合Frを算出した.加工係数Pfと残存割合Frともに,グルテン含有率と変形率80%における荷重値のそれぞれとの間に正の相関が確認され,麺が硬くなるほど茹で湯への放射性セシウムの移行が抑制される傾向にあった.グルテン自体への放射性セシウムの吸着は確認されなかった.茹で麺の含水比の増加割合は,加工係数Pf,残存割合Fr,および変形率80%における荷重値と,それぞれに負の相関が確認された.これらのことから,米粉を原料とする麺において,同じ形状の麺で同じ茹で調理を行う場合,麺が硬いほど麺から茹で湯への137Csの移行が抑制される傾向が示され,この現象には茹で調理での茹で麺の含水比の変化割合の違いが影響を及ぼしている可能性が示唆された.米粉麺の茹で調理における放射性セシウムの動態と類似していた無機元素は,カリウムとナトリウムであった.
官能評価(試験1,2)により,刺激的な香味が軽減された液状ウィンターセイボリーエキス(WSL)の用量(0.25g ; カルバクロール(CAR)含有量 : 0.075mg,チモール(THY)含有量 : 0.015mg)とWSLの濃度(0.25% ; CAR濃度 : 0.75ppm,THY濃度 : 0.15ppm)を決定した.次いで,試験1,2で定めた用量と濃度のWSL含有飲料(DK1) 100mLの摂取試験を行なった(試験3).その結果,上肢(手首,手指),下肢(足首,足指)の体表温低下が有意に抑制され,首の体表温が有意に上昇した.さらに,口腔·咽頭内での刺激が体温変化に関与しているかどうか明らかにするため,ウィンターセイボリーエキス粉末(WSP)(80mg ; CAR含有量 : 0.075mg,THY含有量 : 0.015mg)のカプセル(CP)摂取試験を行なった結果,上肢のみに有意な体表温低下抑制効果がみられた(試験4).次いで,口腔内刺激の強弱を決定する因子となるCAR,THY濃度が重要であるのか明らかにするため,試験3と同用量のWSLを含有し,希釈媒体量を100mLから20mLに低減することでCAR,THY濃度をDK1の5倍に高めたWSL含有飲料(DK2)の摂取試験を行った(試験5).その結果,DK2摂取群(上肢,下肢に有意な体表温低下抑制 ; 額,首に有意な体表温上昇 ; 鼓膜温(深部温)の有意な上昇)は,DK1摂取群(上肢,下肢に有意な体表温低下抑制 ; 首に有意な体表温上昇)に比べ体温に影響がみられる部位が増加した.DK1摂取群とCP摂取群の比較,DK1摂取群とDK2摂取群の比較から,体温変化に,CAR,THYによる口腔·咽頭内の神経刺激が関与していることが示唆された.本結果から,ウィンターセイボリーが手軽に飲用し得る冷え抑制効果素材として有用なことが分かった.さらに,体温変化をもたらす同様な成分についても,口腔·咽頭内刺激を利用することにより,効果が増強される可能性があると考えられる.
The quality control of frying oil and the management of cooking processes are critical to the taste of fried foods, and to the safety and economic efficiency of the commercial production of fried foods. The authors conducted research to assess the degradation of frying oil by studying its electrical properties and observed peculiar behavior of the dielectric constant believed to be caused by water present in the frying oil. An analysis of the dielectric constant suggested that water remains in high-temperature frying oil for a relatively long period of time. It is generally thought that water promptly reaches its boiling point of 100°C when added to high-temperature frying oil and is immediately discharged from the oil and into the atmosphere as steam. Verification that water indeed remains in frying oil at elevated temperature for long periods of time would indicate that there is a mechanism that hinders the discharge of water from high-temperature oil. Accordingly, in this paper we reproduce the conditions in which water remains in the frying oil and consider the factors causing this retention. We also discuss methods for extending the life of frying oils by controlling and managing the degradation of oil caused by hydrolysis when used frying oil is stored.
大豆を磨砕し水に分散させた豆乳は最近,いわゆる “豆乳” とは違った加工素材としての利用が発展している.2015年大会の研究小集会大豆部会では,豆乳ベースの素材開発の背景となる大豆成分の分離技術の原理とその応用を扱った.長年,豆腐凝固過程の解明に取り組まれてきた小野先生には,豆腐用と飲用では豆乳の加熱処理条件が異なり,豆乳コロイド分散系の凝集に関わるタンパク質,オイルボディや共存する凝固剤や各種成分の働きに相違が生じる現象を解説して頂いた.次いで,食品工学的な観点から豆乳を解明し,脂質·油滴に着目されている藤井先生には,豆乳コロイド分散系の構造と凝集過程の挙動の解説,さらに豆乳中の安定なオイルボディをプロテアーゼと加熱処理によって変性させるとクリーム様素材となる実例を示して頂いた.
Soymilk specific for tofu is not used in drinks because of its bean-like flavor. Conversely, soymilk destined for drinks is not used for tofu production because it forms a soft curd. The difference in these soymilks is due to the milling temperature; room temperature is used for tofu, while high temperatures are used to inhibit the activity of oxidative enzymes in soymilk for drinks. The composition of these soymilks was discussed from the viewpoint of the previously described formation mechanism of soymilk and tofu, new data about the components, and recent soymilk composition data for drinks. The results showed that the composition of oil bodies was the same for both tofu and drinks, but the protein fraction for drinks contained a greater level of small particles compared to that for tofu. Thus, precise temperature regulation is important for soymilk processing.
In this paper, the effects of oil bodies, coagulant, pH and enzyme treatment on the aggregation behavior of soymilk were reviewed from the viewpoint of a colloidal dispersion system. The applicability of Einstein's and Krieger-Dougherty's theories of viscosity was examined using soymilk samples. The oil bodies in the soymilk behaved as suspended substances, and it was possible to predict the relative viscosity from the volume fraction of the oil bodies. The coagulation of soymilk with magnesium chloride was also investigated, and the validity of the novel viscous model with the effect of cross-linkage was discussed. The viscosity during coagulation could be predicted by the model, based on particle size as a property of the dispersion system. From the results of the effect of pH on the stability of soymilk using the centrifugal method, the state of soymilk components changed in three steps as a function of decreasing pH. The aggregation of high-fat soymilk digested by papain required heat pretreatment. It was suggested that oleosin, which stabilized the oil body emulsion, was digested by papain and the aggregation was promoted by heat pretreatment.