Figure 4 - uploaded by Gennaro Salvatore Ponticelli
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Bacterial growth curves on a semi-logarithmic scale (a) without pH control and (b) under pH control; lactic acid production during the rice flour fermentation (c) without pH control and (d) under pH control.
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Modelling and predicting of the kinetics of microbial growth and metabolite production during the fermentation process for functional probiotics foods development play a key role in advancing and making such biotechnological processes suitable for large-scale production. Several mathematical models have been proposed to predict the bacterial growth...
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... investigation, statistical analysis, and bacterial growth modelling were performed according to the flowchart reported in Figure 1; the main results are reported and discussed in the following sections. Figure 4 shows the results obtained in terms of bacterial growth and lactic acid fermentation without and under pH control. In particular, the curves are represented on a semilogarithmic scale for a more appropriate interpretation of the results. ...
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... rice flour fermentation of LpCBAL74 was characterized by a starting bacterial load at "zero" time of about 2.64·10 6 ± 1.50·10 6 CFU/mL in non-controlled pH conditions, and of about 2.51·10 6 ± 6.96·10 5 CFU/mL with pH control. From Figure 4a,b it can be observed that during the first 4 h of fermentation the bacterial load is almost constant, regardless of the pH conditions. In fact, during this first part of the fermentation process, the pH remains almost constant, with a very small fluctuation, even in the control absence. ...
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... same can be seen for the final part of the fermentation process, after 18 h, for which the bacterial growth in both scenarios has reached the stationary condition at an average microbial concentration of 2.66·10 8 ± 5.23·10 7 CFU/mL and 2.49·10 8 ± 1.72·10 7 CFU/mL for the controlled and uncontrolled process, respectively, up to the final 24 h concentration of 2.26·10 8 ± 9.35·10 7 CFU/mL and 3.43·10 8 ± 3.26·10 7 CFU/mL, respectively. From Figure 4a,b the different phases of microbial growth for both conditions (under and without pH control) can be clearly identified: the lag, the exponential and the stationary phases lasted, respectively, from 0 h to 4 h, from 4 h to 14 h and from 14 h to 24 h without the pH control; while, in the other scenario, these phases lasted, respectively, from 0 h to 6/8 h, from 6/8 h to 18 h and from 18 h to 24 h. It is worth noting that due to the variability of the results, highlighted by the error bars, the exponential phase cannot be properly identified between 6 and 8 h. ...
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... Error! Reference source not found.a,b the different phases of microbial growth for both conditions (under and without pH control) can be clearly identified: the lag, the exponential and the stationary phases lasted, respectively, from 0 h to 4 h, from 4 To further monitor the fermentation process, also the production of lactic acid was evaluated (Figure 4c,d). Lactic acid was produced during fermentation in both tested conditions between 8 h and 14 h and up to 24 h at the end of the fermentation process. ...
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... this end, the influence of the pH control was evaluated for each sampling time, i.e., at 0, 2, 4,6,8,14,16,18,20,22,24 h, for a total of 11 analyses, the results of which are shown in Table 1. It is worth noting that for the lactic acid production only the values starting from 14 h of fermentation are reported since there is no production before (Figure 4). Moreover, only the contributions considered statistically significant are shown, i.e., with the F-value greater than the corresponding tabulated one, called the critical F-value (in this case equal to 6.61), with the p-value less than 0.05, and a Π% greater than 40%. ...
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... fact, once the exponential growth is established, it indistinctly continues until the stationary phase is reached, beyond 16 h, at which the fermentation process is again influenced by the presence or absence of the pH control. About the lactic acid production, the process is significantly influenced during each step, underlining how the use of pH control favourably promotes the production of lactic acid, as shown in Figure 4d. ...
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... 13, x FOR PEER REVIEW 11 of 18 sence of the pH control. About the lactic acid production, the process is significantly influenced during each step, underlining how the use of pH control favourably promotes the production of lactic acid, as shown in Figure 4Error! Reference source not found.d. ...
