Arroyo López F N, Durán Quintana M C, Garrido Fernández A
Department of Food Biotechnology, Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, Apartado 1078, 41012 Seville, Spain.
J Food Prot. 2007 Feb;70(2):456-65. doi: 10.4315/0362-028x-70.2.456.
A global logistic model was used to study the effects of both quantitative variables (NaCl, acid, and potassium sorbate concentrations) and dummy variables (laboratory medium or brine, and citric, lactic, or acetic acids) on growth of Saccharomyces cerevisiae IGAL01. The deduced equations, with the significant coefficients selected by a backward stepwise procedure, allowed estimations of the simultaneous comparison of behaviors of levels of the qualitative variables as a function of the quantitative variables and the development of the growth-no growth limits according to laboratory medium or brine and the different types of acidifying agents. The S. cerevisiae growth region in yeast malt glucose peptone broth was always wider than that in brine, in which this yeast was inhibited by 0.03% potassium sorbate and 6% NaCl, when the acid concentration (regardless of type) was 0.2 to 0.3%. These results demonstrate the applicability of such model designs to include qualitative variables in investigations related to the development of growth-no growth limits.
采用全局逻辑模型研究定量变量（氯化钠、酸和山梨酸钾浓度）以及虚拟变量（实验室培养基或盐水，以及柠檬酸、乳酸或乙酸）对酿酒酵母IGAL01生长的影响。通过向后逐步程序选择显著系数后推导得出的方程，能够估计定性变量水平行为随定量变量的同时比较情况，并根据实验室培养基或盐水以及不同类型的酸化剂确定生长-不生长界限。当酸浓度（无论类型）为0.2%至0.3%时，酿酒酵母在酵母麦芽葡萄糖蛋白胨肉汤中的生长区域始终比在盐水中的宽，在盐水中该酵母会受到0.03%山梨酸钾和6%氯化钠的抑制。这些结果证明了此类模型设计在与确定生长-不生长界限相关的研究中纳入定性变量的适用性。
