Studies on methods for keeping quality of \u22Kamaboko\u22, a cooked fish paste III : Effectiveness of chemical and physical treatments on the shelf-life of \u22Kamaboko\u22.

In the previous papers, it was reported that the casing with cellophane, the irradiation by infrared and/or ultraviolet ray showed a marked prolongation of shelf-life of \u22 Kamaboko \u22. It was further noticed that when the preservatives were smeared on the surface, the combination of the preservatives and casing was rather inferior to the control group without casing. However, when the preservatives were mixed with the paste, the combination did not show any inferior effect to the control. The present paper deals with a comparison of the effectiveness between preservatives which were mixed with the paste and those which were applied on the surface, and further with the effectiveness of casing with cellophane, polyvinyl alcohol and polyvinyl acetate film and of infrared and/or ultraviolet ray irradiation all over the surface of \u22Kamaboko\u22. 1. When the preservatives were mixed with the paste, dehydroacetic acid and its sodium salt were effective in prolonging the storage life to six and four days, respectively, in contrast to two days in the control at 26℃. However, the preservatives which were smeared on the surface were not effective (See Tables 1 and 2). 2. Among the preservatives which were mixed with the \u22Kamaboko\u22, butyl p-hydroxybenzoate and o-hydroxybenzamide showed effectiveness to some extent on keeping quality (See Table 3). 3. The casing with polyvinyl alchol film gave rather an inferior result. The combination of the casing with polyvinyl alcohol film and the mixing with preservatives shortened the shelf-life compared to the control (See Table 4). 4. In the case of \u22 Kamaboko \u22 without the casing, irradiation by the infrared ray for short time prevented the growth of bacteria. However, irradiation by ultraviolet ray showed remarkable effect on inhibition of bacterial growth. Irradiation by ultraviolet ray twice daily was slightly more effective than that once daily. The combination of irradiation by ultraviolet ray twice daily and that by infrared ray every other day was effective in prolonging the storage life to five days in contrast to two days in the control without the irradiation (See Table 5, Figs. 1a, 1b and 1c). 5. Irradiation by ultraviolet ray over \u22 Kamaboko \u22 which was covered with cellophane or polyvinyl cetate was also effective. No difference was observed between the irradiation once daily and twice daily (See Table 6, Figs. 1a, 1b and 1c). 6. Daily irradiation by ultraviolet ray all over the surface of \u22Kamaboko\u22 which contained DHA at a 0.1 % level and covered with cellophane or polyvinyl acetate was able to prolong the storage life to 10 days in contrast to a storage life of two days in the control at 26℃ (See Tables 7 and 8).1. 無包装の板付無糖蒲鉾を用い,数種の防腐剤を塗布した場合と練り込んだ場合との効果を比較したところ, DHA及びDHA-NaはO.2%の濃度でいずれも蒲鉾の表面に塗布した場合は無効であつたが, 練り込んだ場合は鮮度保持に有効であった. 2. 数種の防腐剤を練り込んだ場合の効果を検討したところ, パラオキシ安息香酸ブチルェステル及びサリチル酸アミドが0.1或は0.2%の濃度で鮮度保持効果が認められた. またDHA或はDHA-Naとパラオキシ安息香酸ブチルエステル或は第四級アミンQA(BB)の相乗効果について検討したところ,殆んど認められなかつた. 3. ポリビニールアルコールで被覆すると無包装よりも悪く,また防腐剤の効果も一般に低下した. 4. 無包装の場合には, 短時間の赤外線照射はカビの発育を抑えるが, 細菌に対しては効果弱く, 逆に紫外線はカビに対して効果が弱いが, 細菌に対しては極めて有効であつた. また紫外線照射は1日1回よりも2回の方が多少有効であつた. 従つて30cm距離からの15W殺菌灯による15分間全面照射を2回毎日繰り返し, 之に隔日に赤外灯(500W,30cm距離)を5分間照射すると, 5日間鮮度が保持された. 5. セロファン或は醋酸ビニールで全面を覆うと, カビの二次的汚染が少いためか, 赤外線照射の効果は認められなかつたが, 紫外線照射は有効であつた. この場合には1日に1回照射した時と2回超射した時との間に殆んど差がなかつた. 6. DHAを1/1,000練り込み, セロファン或は醋酸ビニールで被覆し, 紫外線を毎日1回15分間全面照射すると, 少くとも26℃で10日間鮮度が保持された