Evaluation of heat-treated frying oils (Part V) : Animal study in relation to analytical values of heat-treated soybean oils

[Author abstract]The objective of the study is to substantiate the meaning of P/AP values proposed previously by showing correlations between the values and the observations made by animal feeding study. Soybean oil was heated at 180°C by frying 2, 4 and 6 kg each of potatoes, chicken meat balls and sliced mackerel meat in 10,20 and 30 hr, respectively; the oil samples are designated, respectively, as P-10, P-20, P-30, C-10, C-20, C-30, M-10, M-20 and M-30. A fairly good correlation was obtained between the amounts of the polar fraction formed by heating (determined by adsorption chromatography on a silica gel column) and P/AP values, r=0.79 at 233 nm and r=0.72 at 280 nm. Male Sprague-Dauley rats, 7 animals/group, were fed each of the heated oils at a level of 10% for 35 - 50 days. The animals fed P-10 - P-20 and C-10 - C-30 showed a similar trend of growth retardation, whereas those fed M-10 and M-20 no retardation in an early stage of feeding and only those fed M-30 some retardation after 20 or more days of feeding. All the groups, except those fed M-10 and M-20, showed a significant difference (p<0.05) in body weight gains from the control group after 35 days. The P/AP values of P-10 - P-30 correlated well with the decreases in body weight gains of the animals fed the same oils, r=-0.75 at 233 nm and r=-0.72 at 280 nm. A significant difference (P<0.05) in liver weight/body weight was observed between the control group and the groups fed P-30, C-20 and M-30. The UV absorbance of the polar fraction of liver lipids (separated by TLC) from animals fed 20 hr and 30 hr heated oils, disregarding effects of food items used, was found to give significant differences of p<0.05 and <0.001 respectively, from that of the control group. Discussions are given on deterioration of fats and oils in relation to yields of polar fractions and to P/AP values and also on comparison between the proposed method and those methods (GPC, LC and CC) recently examined by Billek et al. [著者抄録]本実験の目的は,先に提唱したP/AP値の意義を動物実験の知見との関連を示すことにより証明することである.大豆油はポテト,鶏肉ダンゴ,鯖肉片を各々につき,2kg,4kg,6kgを10,20, 30時間,180°Cでフライしながら加熱した.:試料地は,P- 10,P- 20,P-30,C-10,C-20,C-30,M-10,M-20,M-30とする.加熱により生成した極性部量(シリカゲル力ラムの吸着クロマトグラフィーにより測定)とP/AP値の間にはかなり良好な相関関係r=0.79(233 nm),r=0.72(280nm)が得られた.S.D.系ラット(7匹/群)を10%レベルの各試料油で35～50日間飼育した.P-10～P-30とC-10～C-30で飼育したものは同様な成長遅延の傾向がみられた.一方,M-10,M-20で飼育したものは飼育の初期段階ではなく,M-30で飼育したもののみ,20日以上の飼育で多少の遅延があった. M-10, M-20を除くすべての飼育群は35日後,体重増加について対照群と有意差(P<0.05)を示した.P-10～P-30のP/AP値は同じ試料油で飼育したラットの体重増加の減少との間にかなりよい相関を示した.r=-0.75(233 nm ),r=-0.72(280nm).肝臓重量/体重については対照群とP- 30,C- 20,M- 30との間に有意差(P<0.05)があった.種物のの影響を無視して,20 hr, 30hr加熱の試料油で飼育したラットの肝脂質の極性部の紫外吸収は対照群との間に,各々P<0.05,P