Department of Food Science, New York State Agricultural Experiment Station, Cornell University, 630 West North Street, Geneva, New York 14456, USA.
Department of Food Science, New York State Agricultural Experiment Station, Cornell University, 630 West North Street, Geneva, New York 14456, USA
J Food Prot. 2014 May;77(5):788-95. doi: 10.4315/0362-028X.JFP-13-362.
U.S. federal regulations require that acidified foods must reach a pH of 4.6 or lower within 24 h of packaging or be kept refrigerated until then. Processes and formulations should be designed to satisfy this requirement, unless proper studies demonstrate the safety of other conditions. Our objective was to determine the effect of brine acetic acid concentration and packing conditions on the acidification rate of hard-boiled eggs. Eggs were acidified (60/40 egg-to-brine ratio) at various conditions of brine temperature, heat treatment to filled jars, and postpacking temperature: (i) 25 °C/none/25 °C (cold fill), (ii) 25 °C/none/2 °C (cold fill/refrigerated), (iii) 85 °C/none/25 °C (hot fill), and (iv) 25 °C/100 °C for 16 min/25 °C (water bath). Three brine concentrations were evaluated (7.5, 4.9, and 2.5% acetic acid) and egg pH values (whole, yolk, four points within egg) were measured from 4 to 144 h, with eggs equilibrating at pH 3.8, 4.0, and 4.3, respectively. Experiments were conducted in triplicate, and effects were considered significant when P < 0.05. Multiple linear regression analysis was conducted to evaluate the effect on pH values at the center of the yolk. Regression analysis showed that brine concentration of 2.5% decreased the acidification rate, while packing conditions of the hot fill trial increased it. Inverse prediction was used to determine the time for the center of the yolk and the total yolk to reach a pH value of 4.6. These results demonstrate the importance of conducting acidification studies with proper pH measurements to determine safe conditions to manufacture commercially stable pickled eggs.
美国联邦法规要求酸化食品在包装后 24 小时内 pH 值必须达到 4.6 或更低，或者在此之前冷藏。除非进行适当的研究证明其他条件是安全的，否则应设计工艺和配方以满足这一要求。我们的目的是确定盐水醋酸浓度和包装条件对煮硬蛋酸化速率的影响。鸡蛋在不同的盐水温度、灌装后热处理和包装后温度条件下进行酸化（60/40 蛋与盐水的比例）：（i）25°C/无/25°C（冷灌装），（ii）25°C/无/2°C（冷灌装/冷藏），（iii）85°C/无/25°C（热灌装）和（iv）25°C/100°C 16 分钟/25°C（水浴）。评估了三种盐水浓度（7.5%、4.9%和 2.5%醋酸），并从 4 到 144 小时测量了鸡蛋的 pH 值（整个鸡蛋、蛋黄、鸡蛋内的四个点），鸡蛋分别在 pH3.8、4.0 和 4.3 下平衡。实验重复进行了三次，当 P<0.05 时，认为有影响。进行了多元线性回归分析，以评估对蛋黄中心 pH 值的影响。回归分析表明，2.5%的盐水浓度降低了酸化速率，而热灌装试验的包装条件增加了酸化速率。利用逆预测法确定蛋黄中心和整个蛋黄达到 pH 值 4.6 的时间。这些结果表明，进行适当的 pH 值测量的酸化研究对于确定商业稳定腌制蛋的安全条件非常重要。
