過氧化氫對豆乾保存性之影響   全文下載

Effects of the Application of Hydrogen Peroxide on the Preservation of Firm Tofu

本研究之主要目的為探討過氧化氫用於豆乾保存之使用量。豆乾為高水分含量、高水活性、低酸性食品，貯藏並不容易，而過氧化氫對於此類產品有很好的保存效果。過氧化氫之分析方法中，過氧化?法所得到之迴歸曲線為Y=0.314X-0.0845 （R2=0.998），而Merck RQflex Reflectometer法所得到之迴歸曲線為Y=1.03X-0.438 （R2=0.977），兩者均為很精確的分析方法，Merck RQflex Reflectometer法則較為簡單、方便。未經過氧化氫處理之豆乾在室溫下只有1天的保存期限，要在室溫下貯藏2天，則需含有95 ppm的過氧化氫，貯藏3天，則需含395 ppm；若以冷藏的方式貯藏，未經過氧化氫處理之樣品可貯藏1～4天，但須控制樣品之初始菌數在103 cfu／g以下。豆乾以過氧化氫處理可以使Hunter L值增高，但對a值及b值則無顯著影響。酒精對此類產品之保存效果並不顯著。水煮及油炒過程能使過氧化氫含量降低，但在高濃度時，並不容易經由烹調過程而完全分解。 In this study, hydrogen peroxide concentrations for treatment of firm tofu was investigated. Because firm tofu has high moisture content, high water activity, and is a low-acid food, it is difficult to preserve. Hydrogen peroxide treatment could possibly be a good preservative. The analytical methods for hydrogen peroxide, obtained regression equations by the peroxidase method and Merck RQflex. Reflectometer methods were Y=0.314X-0.0845 (R2=0.998) and Y=1.03X-0.438 (R2=0.977), respectively. These were accurate methods for hydrogen peroxide analysis, with the Merck RQflex Reflectometer method being the more convenient method. The shelf-life at room temperature of firm tofu is 1 day without hydrogen peroxide treatment. The shelf-life at room temperature of firm tofu was extended to 2 and 3 days when the hydrogen peroxide contents were 95 and 395 ppm, respectively. If the initial count is less than 103 cfu/g, the products can be stored at 4°C for 1 to 4 days without hydrogen peroxide treatment. Hydrogen peroxide treatment significantly increased the Hunter L value, but had no significant effect on the Hunter a value and the Hunter b value of the products. Alcohol treatment was not an effective method for preserving firm tofu. Cooking foods containing hydrogen peroxide reduced the amount of residual hydrogen peroxide, however it was not easy to remove all residual hydrogen peroxide by cooking when the hydrogen peroxide concentration was high."

In this study, hydrogen peroxide concentrations for treatment of firm tofu was investigated. Because firm tofu has high moisture content, high water activity, and is a low-acid food, it is difficult to preserve. Hydrogen peroxide treatment could possibly be a good preservative. The analytical methods for hydrogen peroxide, obtained regression equations by the peroxidase method and Merck RQflex. Reflectometer methods were Y=0.314X-0.0845 (R2=0.998) and Y=1.03X-0.438 (R2=0.977), respectively. These were accurate methods for hydrogen peroxide analysis, with the Merck RQflex Reflectometer method being the more convenient method. The shelf-life at room temperature of firm tofu is 1 day without hydrogen peroxide treatment. The shelf-life at room temperature of firm tofu was extended to 2 and 3 days when the hydrogen peroxide contents were 95 and 395 ppm, respectively. If the initial count is less than 103 cfu/g, the products can be stored at 4°C for 1 to 4 days without hydrogen peroxide treatment. Hydrogen peroxide treatment significantly increased the Hunter L value, but had no significant effect on the Hunter a value and the Hunter b value of the products. Alcohol treatment was not an effective method for preserving firm tofu. Cooking foods containing hydrogen peroxide reduced the amount of residual hydrogen peroxide, however it was not easy to remove all residual hydrogen peroxide by cooking when the hydrogen peroxide concentration was high.