Abstract
The aim of this work was to investigate the effect of pulsed electric fields (PEF) on the growth and acidification kinetics of Lactobacillus delbrueckii subsp. bulgaricus CFL1 during fermentation. The PEF treatments were applied during the fermentation process using a recirculation pump and a PEF treatment chamber coupled with a PEF generator. The medium flow rate through the chamber was first optimized to obtain the same growth and acidification kinetics than the control fermentation without medium recirculation. Different PEF intensities (60–428 V cm−1) were then applied to the culture medium to study the impact of PEF on the cells’ behavior. The growth and acidification kinetics were recorded during the fermentation and the specific growth rates µ, pH, and acidification rate (dpH/dt) were assessed. The results obtained showed a biphasic growth by applying high PEF intensities (beyond 285 V cm−1) with the presence of two maximal specific growth rates and a decrease in the acidification activities. It was demonstrated that the cells were stressed during the PEF treatment, but presented an accelerated growth after stopping it, leading thereby to similar absorbance and pH at the end of the fermentation. These results show the great potential of PEF technology to be applied to generate low acidified products by performing PEF-assisted fermentations.
Highlights
Lactic acid bacteria (LAB) have extensive industrial applications as producers of lactic acid, as probiotics, as biocontrol agents, and as bio preservatives [1]
The impact of medium circulation through the treatment chamber without pulsed electric fields (PEF) application was studied on the growth and acidification kinetics of L. delbrueckii subsp. bulgaricus CFL1 at the flow rates of 25 ± 2 mL min−1 and 50 ± 5 mL min−1
It could be concluded from the results obtained that PEF treatment stressed the cells, which was shown by a biphasic growth and a reduced acidification activity
Summary
Lactic acid bacteria (LAB) have extensive industrial applications as producers of lactic acid, as probiotics, as biocontrol agents, and as bio preservatives [1]. The main application of LAB is as starter cultures in the food industry with a wide variety of fermented dairy products, meat, fish, fruit, vegetable, and cereal products [2]. Bulgaricus is a representative lactic acid bacterium that is extensively used for the production of the most popular types of fermented milk [7,8]. It can convert carbohydrates, such as glucose and lactose, to lactic acid [9], which may contribute to the texture and aroma of different food products [10]. The strain Lactobacillus delbrueckii subsp. bulgaricus is a representative lactic acid bacterium that is extensively used for the production of the most popular types of fermented milk [7,8].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
