Takahide Okayama

Effect of ascorbic acid and alpha-tocopherol on storage stability of beef steaks

Fresh beef loin steaks were dipped in solutions of (1) 70% ethyl alcohol (EtOH). (2) 70% EtOH containing 3% l-ascorbic acid (AsA), (3) 70% EtOH containing 0·08% dl-α-tocopherol (Toc) and (4) 70% EtOH containing 3% AsA plus 0·08% Toc for 20 s, then drained for 10 s. Control samples received no dip treatment. After 3, 6, 9 and 13 days of storage at 4°C, the samples were evaluated for MetMb formation, TBA number and viable bacterial count. The beef steaks given AsA treatment maintained an acceptable meat colour for 13 days of storage. The TBA numbers of samples dipped in EtOH containing AsA stored for 13 days were significantly lower than those of controls, and in samples dipped in solutions without AsA. At 9 and 13 days of storage, the AsA plus Toc-treated samples gave lower TBA numbers than the samples given AsA treatment only. Viable bacterial counts were not affected by AsA, Toc or AsA plus Toc treatment. Beef loin steaks dipped in EtOH solution maintained a viable bacterial count of 10(6) after 13 days of storage.

Effect of cooking temperature on the percentage colour formation, nitrite decomposition and sarcoplasmic protein denaturation in processed meat products.

The effect of cooking temperature and time on the percentage colour formation, nitrite decomposition and denaturation of sarcoplasmic proteins in processed meat products was investigated in detail. The colour forming percentage increased with a rise in temperature of heating, especially at 50-60°C (P < 0·05). The percentage nitrite decomposition was promoted by the retention time of cooking rather than by the cooking temperature (P < 0·05). The percentage of sarcoplasmic proteins denatured was enhanced by heating temperature in the range 50-80°C (especially at 50-60°C) (P < 0·05). The relationship between the percentage colour formation and the percentage of sarcoplasmic proteins denatured is discussed. The SDS-PAGE patterns of the heat-treated samples revealed the components of the sarcoplasmic proteins which had been denatured.

Changes in Low-Molecular Weight Components in Sarcoplasmic Fraction during Conditioning of Japanese Black Cattle

黒毛和種腿肉の熟成中における筋漿低分子量成分の変化を追究する目的で,筋漿画分の透析外液として得られた筋漿低分子量画分と筋肉ホモジネートの加熱処理で得られたスープ画分のペプチド含量の変化および低分子量用の市販ゲルを用いたSDS-ポリアクリルアミドゲル電気泳動(PAGE)像の変化を指標として調査した.屠殺後0,2,4,6,8,10,14,17,21日間熟成した筋漿低分子量画分とスープ画分のペプチド含量を測定した結果,筋漿低分子量画分は熟成2日と6日試料の値を除いて,熟成が進行するに伴い次第に増加した.スープ画分は熟成が進行するに伴いほぼ直線的に著しく増加した.筋漿画分のSDS-PAGE像の結果から,約4.6キロダルトン(kD)の成分は熟成0日では認められなかったが,熟成2日以後出現した.約3.0kDの成分は稀薄なバンドとして熟成4,6,8,10,14日試料にのみ認められた.スープ画分のSDS-PAGE像の結果から,約8.0kDと約3.6kDの成分は熟成0日と2日試料では少量であったが,熟成10日以降の試料ではかなり多量に認められ,特に約3.6kD成分は著しく増加した.

Effects of ribose, xylose and arabinose on colour formation in processed meat products

The effects of ribose, xylose and arabinose on colour formation of meat products processed by emulsion curing were investigated in an aqueous model system under anaerobic conditions. Ribose markedly enhanced the colour forming ability, nitrite decomposition and reducing ability, depending upon its initial concentration; and xylose and arabinose exhibited some promoting effects on them. The colour promoting effects of ribose, xylose and arabinose increased with a rise in pH, in agreement with the results for reducing ability. This suggested that the reducing ability of ribose, xylose and arabinose plays a key role in promoting colour formation of meat products in emulsion curing.

Effect of Sarcoplasm from Porcine Skeletal Muscle on the Formation of Cooked Cured Meat Color

豚の内転筋より調製した筋漿を,水に対する透析法によって高分子と低分子の2画分に分け,亜硝酸塩の分解および発色効果に及ぼすこれらの画分の影響を比較検討した.高分子画分も低分子画分も共に亜硝酸塩を分解する作用ならびに発色を促進する効果が大きかったが,いずらの作用効果も低分子画分のほうが高分子画分より顕著であった.筋漿低分子画分をSephadex G-50によるゲル濾過法で分析した結果,管数35～42(Kd=0.8～1.1)内に顕著な発色促進効果を示す成分が溶出さら,得られた画分の発色促進効果と亜硝酸塩分解作用および還元力はよく対応し,またSH基,ニンヒドリン陽性物質および糖類を多く含むことが認められた.また紫外吸収特性による検討により,248nmにおける吸光度が最大を示す管数40(Kd=1.0)の画分中にかなりの量のイノシンあるいはその誘導体の存在が推定された.