Yoshimasa Yamano

EFFECT OF DROPLET SIZE ON OXIDATION OF DOCOSAHEXAENOIC ACID IN EMULSION SYSTEM

Abstract We investigated the effect of oil droplet size on the oxidation rate of DHA monodispersed emulsion with xanthan. Xanthan-free emulsions creamed rapidly but no creaming was observed in the emulsions containing xanthan over 8 weeks. While the peroxide value (POV) of the xanthan-free emulsion reached 10meq/ kg at 20 days, that of both emulsion systems containing xanthan changed little during the first 20 days. The POV for the emulsion with small droplet was higher than that for the emulsion with large droplet.

EFFECT OF SOME POLYSACCHAR1DES ON OXIDATIVE STABILITY OF METHYL LINOLEATE IN EMULSION

ABSTRACT In a model emulsion system consisting of 10% w/w of methyl linoleate and 0.5% w/v of Tween 20 as an emulsifier in a 0.05 M sodium acetate buffer (pH 4.0) with polysaccharide, locust bean gum, xanthan and glucomannan considerably inhibited oxidation, as proved by the change in peroxide value. Carrageenan and chitosan had no or only a small effect on oxidation. There was no evidence of organic radical scavenging activity as shown by ESR, but oxidation inhibiting polysaccharides manifested an iron binding activity.

ASYMMETRY IN LIPOSOME

ABSTRACT Asymmetry of phospholipid distribution along the vertical axis of the bimoiecular membrane in a liposome prepared with soybean phospholipids, PC and PE, was studied by using on ESR technique. From the difference in the values of the order parameter of doxylstearic acid radicals between the sample solutions into which the radicals were added before and after preparation of the liposome, it was concluded that PE is incorporated only in the inner layer of the liposome in the range of 0-30% of PE in mixed PC/PE systems and PE is incorporated in both layers of the liposome over about 30% of PE in the mixture.

Relationship Between Macroscopic and Microscopic Viscosities in Starch Gels

Abstract We investigated the relationship between the macroscopic viscosity lpar;ηN ), determined by creep measurement, and the microscopic viscosity, estimated by rotational correlation time (τc) of spin label determined by ESR method, for wheat and potato starch gels. Both ηNand τc. Of wheat starch gel increased linearly with an increase of starch concentration. Both ηN and τc of potato starch gel increased exponentially with an increase of starch concentration. The τc of wheat starch gel related linearly to the ηN of the gel at 30, 40 and 50°C. For potato starch gels, the τc.also related significantly to the ηN at 30, 40 and 50°C. The τc of free BrAcTEMPO was much smaller than that of spin-labeled AcTEMPO in wheat starch gel. It is concluded that the change in microscopic viscosity of starch gels agrees with their change in macroscopic viscosity.

Rheological properties and microstructure of monodispersed O/W emulsion agar gel

Publisher Summary This chapter describes the effect of oil droplet on the rheological properties and microstructure of monodispersed OAV emulsion agar gel prepared by membrane emulsification technique is investigated by mechanical measurements and SEM observation. An emulsion gel containing oil droplets is a good food model. Oil droplet size and oil volume fraction have important effects on the texture and rheological properties of the emulsion gel. This chapter investigates the effects of oil droplet size and volume fraction on the rheological properties and to observe microstructure of emulsion agar gel by mechanical measurements and SEM observation. Agar powder (1%) is dispersed in the emulsions containing 0.1,0.2 and 0.3 volume fractions of oil, after which these agar emulsion dispersions were stirred gently for 60 min at 20°C, heated for 30 min at 70°C and then heated again for 30 min at 9 0°C during swelling. After being degassed, these sols are poured into cylindrical glass containers (inside diameter 24 mm, height 38 mm). These glass containers are held for one hour at room temperature and then held in a water bath for 24 hours at 25°C before measurements. In each gel, the uniformity of dispersibility of emulsion droplets is confirmed by determining droplet number and diameter at top, center and bottom of emulsion gel. The compressive gel strength of emulsion gel decreases with an increase in oil droplet size, while that of emulsion gel determined by puncture test shows almost no change. It also includes Cryo-SEM observation reveals that oil droplets aggregated in the emulsion gel and that the gel had some void spaces between gel network and the oil droplet aggregate.

Effects of Preparing Conditions on the Physical Properties of Noodle during Drying Process.

めんの乾燥中の力学的性質の変化および茹めんの物理的性質の変化に及ぼす調製条件の影響ついて検討し,次の結果を得た.(1) 乾燥中のめんの水分含量に対する曲げ強度と曲げヤング率の対数値は乾燥初期に急激に増加し,漸次緩慢に,上に凸の形で増加した.しかし,生地を酸化あるいは生地pHを7よりアルカリ側にしためんでは,曲げ強度および曲げヤング率は凹状に増加した.(2) 乾めんの曲げ強度および曲げヤング率は食塩や乳化油脂を添加すると減少した.生地の加水量42.5-45.0%で乾めんの曲げ強度は高い値を示したが,曲げヤング率に対する加水量の影響は小さかった.生地の熟成および生地の酸化あるいは還元が乾めんの力学的強度に対する影響は小さかった.生地のタンパク質含量が増加すると力学的強度は増加した.(3) 茹めんの切断強度は乾燥の進行とともに水分含量25%付近まで低下し,さらに乾燥すると再び増加した.食塩添加量が増加すると,茹めんの切断強度が最低値を示す乾燥中のめんの水分含量が低下した.生地の熟成は乾燥中のめんの水分含量25%以下で効果がみられ,茹めんの切断強度は増加した.生地の酸化と還元が乾燥中のめんの茹めんの切断強度に対する影響は小さかった.乳化油脂を添加すると茹めんの切断強度は減少した.生地pHがグルテンの等電点の7付近からアルカリ側の生地から調製した乾燥工程中のめんの茹めんの力学的強度は,より低いpHの生地からのめんよりも高い値を示した.

Computerized Image Analysis of Gas Cell Distribution in Several Foods

Computerized image analysis was very practical for determining both the gas cell distribution in bread and sponge cake and the hole distribution in kori tofu because of its rapid, convenient measuring procedure. Both the number and the area ratio of gas cells correlate to the specific volume in both bread and sponge cake. Both the diameter and the area of holes decreased with swelling by water uptake in kori tofu.

Structure Observation of Sesame (Sesamum indicum) Seed by Scanning Electron Microscope

ゴマ種子を生のもの,焙煎したもの,水に浸漬し乾燥したもの,浸漬した後焙煎したものの四点につき組織の変化を走査型電子顕微鏡で観察した. 焙煎によって,細胞壁と細胞内の油滴をつなぐ構造体が収縮した.また,水浸漬によって細胞壁及び油滴周辺の組織が膨潤し,その結果細胞の形が不定形になった.これを焙煎すると細胞壁は破壊され,細胞内の油滴も形を失った.