Abstract
Streptococcus infantarius ssp. infantarius 25124 (Sii-25124) is a lactic acid bacterium (LAB) isolated from pozol, a refreshing beverage prepared by suspending fermented nixtamal (a thermal and alkali-treated maize dough) in water. Although Lactobacillus are the predominant strains in fermented doughs, such as sourdoughs, and non-nixtamalized fermented maize foods, the pozol microbiota is markedly different. This may be the result of the nixtamalization process, which could act as a selective force of some strains. Sii-25124 has been reported as the main amylolytic LAB in pozol; starch is the primary carbon source on nixtamal since monosaccharides and disaccharides are lost during nixtamalization; however, non-amylolytic LAB counts are higher than amylolytic LAB in pozol after 24-h fermentation suggesting that another carbon source is being used by the former bacteria. Hemicellulose (arabinoxylan in maize) becomes available via nixtamalization and is subsequently metabolized by LAB. The aim of this work was to determine whether this bacterium is able to use arabinoxylan as the only carbon source in a defined medium containing arabinoxylan extracted from either nejayote (wash water produced during nixtamal preparation), or beechwood xylan. Xylanase activity in the presence of nejayote arabinoxylan (135.8 ± 48.7 IU/mg protein) was higher than that of beechwood (62.5 ± 19.8 IU/mg protein). Other enzymatic activities, such as arabinofuranosidase and acetyl esterase, were also detected, suggesting the adaptation of the bacterium studied to nixtamal dough. It was concluded that Streptococcus infantarius 25124 isolated from pozol was able to use arabinoxylans, which are present in nixtamal dough, so fermentation does not depend exclusively on free sugars and starch.
Highlights
Pozol is one of the most important traditional pre-Columbian non-alcoholic beverages in southeastern Mexico, where it is consumed as part of the daily diet
Kaindi et al (2018) isolated bacteria of the same subspecies from African dairy products, which were clearly different from the human strain Streptococcus infantarius ssp. infantarius
The purpose of this work was to determine whether Streptococcus infantarius ssp. infantarius 25124 (Sii-25124) is able to use either maize arabinoxylan or beechwood xylan as carbon source, and whether it possesses the functional enzymes needed to hydrolyze both polysaccharides
Summary
Pozol is one of the most important traditional pre-Columbian non-alcoholic beverages in southeastern Mexico, where it is consumed as part of the daily diet It is made of fermented nixtamal (heat- and alkali-treated maize dough). A complex microbiota is found in the fermenting dough; the microbial ecology of pozol has been studied by Ampe et al (1999), Ben Omar and Ampe (2000), Escalante et al (2001), and Díaz-Ruiz et al (2003) They found a variable diversity of species, which after 24 h of fermentation are reduced to strains belonging mainly to the genera Streptococcus, Weissella, Enterococcus, and Lactococcus. Infantarius strains have been isolated from traditional fermented dairy products for example maasai fermented milk and Fènè (fermented cow milk) (Jans et al, 2017).
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.
