Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil.
Food Processing and Quality, Innovative Food System Unit, Natural Resources Institute Finland (Luke), FI-02150, Espoo, Finland.
Appl Microbiol Biotechnol. 2020 May;104(9):4071-4080. doi: 10.1007/s00253-020-10534-x. Epub 2020 Mar 16.
This study aimed to model the inactivation of Lactobacillus brevis DSM 6235 while retaining the viability of yeasts during washing brewer's yeast with phosphoric acid and chlorine dioxide. The independent variables in the acid washing were pH (1-3) and temperature (1-9 °C), whereas in the washing with chlorine dioxide, concentration (10-90 mg/L) and temperature (5-25 °C) were assessed. The predictive models obtained for the four response variables γ, γ (decimal reduction of L. brevis DSM 6235), V/V0, and V/V0 (brewer's yeast viability ratio) were found to have R > 0.80 and values of F > F. Then, the models were considered predictive and statistically significant (p < 0.10). Our results indicated that phosphoric acid and chlorine dioxide washing resulted in up to 7 and 6.4 (log CFU/mL) decimal reductions of L. brevis DSM 6235, respectively. On the other hand, the viability of the brewer's yeast ranged from 22.3 to 99.4%. L. brevis DSM 6235 inactivation was significantly influenced by parameters pH(Q) and T°C(Q) when phosphoric acid was applied, and by parameters mg/L(L), mg/L(Q), T°C(Q), and mg/L × T°C when ClO was applied. The validation of the models resulted in bias (γ, 0.93/V/V, 0.99 - γ, 1.0/V/V, 0.99) and accuracy values (γ, 1.12/Vf/V, 1.01 - γ, 1.08/V/V, 1.03). The results of this study indicate that it might be possible to decontaminate brewer's yeast through acid and chlorine dioxide washing while keeping its viability. This procedure will result in the reduction of costs and the lower generation of brewer's waste.
本研究旨在模拟酿酒酵母洗涤过程中,使用磷酸和二氧化氯处理时,短乳杆菌 DSM 6235 的失活,同时保持酵母的活力。酸洗过程的自变量为 pH 值(1-3)和温度(1-9°C),而二氧化氯洗涤过程的变量为浓度(10-90mg/L)和温度(5-25°C)。对四个响应变量γ、γ(短乳杆菌 DSM 6235 的十进制减少数)、V/V0 和 V/V0(酿酒酵母活力比)进行预测建模,结果发现 R 值均大于 0.80,F 值均大于 F 值。然后,这些模型被认为是具有预测性和统计学意义的(p<0.10)。我们的研究结果表明,磷酸和二氧化氯洗涤分别导致短乳杆菌 DSM 6235 的数量减少了 7 倍和 6.4 倍(log CFU/mL)。另一方面,酿酒酵母的活力范围为 22.3%至 99.4%。当使用磷酸时,L. brevis DSM 6235 的失活受到 pH(Q) 和 T°C(Q) 参数的显著影响,而当使用 ClO 时,失活受到 mg/L(L)、mg/L(Q)、T°C(Q) 和 mg/L×T°C 参数的显著影响。模型验证结果产生了偏差(γ,0.93/V/V,0.99-γ,1.0/V/V,0.99)和准确性值(γ,1.12/Vf/V,1.01-γ,1.08/V/V,1.03)。本研究结果表明,通过酸和二氧化氯洗涤来去除酿酒酵母中的污染物,同时保持其活力是可行的。该方法将降低成本并减少酿酒废弃物的产生。