Cerrado and Pantanal fruit flours affect gut microbiota composition in healthy and post-COVID-19 individuals: an in vitro pilot fermentation study.

Cerrado and Pantanal plants can provide fruits with high nutritional value and antioxidants. This study aims to evaluate four fruit flours (from jatobá pulp, cumbaru almond, bocaiuva pulp and bocaiuva almond) and their effects on the gut microbiota in healthy (HD) and post-COVID-19 individuals (PC). An in vitro batch system was carried out, the microbiota was analysed by 16S rRNA amplicon sequencing and the short-chain fatty acids ratio was determined. Furthermore, the effect of jatobá pulp flour oil (JAO) on cell viability, oxidative stress and DNA damage was investigated in a myelo-monocytic cell line. Beyond confirming a microbiota imbalance in PC, we identified flour-specific effects: (i) reduction of Veillonellaceae with jatobá extract in PC samples; (ii) decrease in Akkermansia with jatoba and cumbaru flours; (iii) decreasing trend of Faecalibacterium and Ruminococcus with all flours tested, with the exception of the bocaiuva almond in HD samples for Ruminococcus and (iv) increase in Lactobacillus and Bifidobacterium in PC samples with bocaiuva almond flour. JAO displayed antioxidant properties protecting cells from daunorubicin-induced cytotoxicity, oxidative stress and DNA damage. The promising microbiota-modulating abilities of some flours and the chemopreventive effects of JAO deserve to be further explored in human intervention studies.

Characterization of a fermented coconut milk product with and without strawberry pulp.

The development of plant-based milks for use as functional foods is relatively new and challenging. The objective of this work was to develop and characterize two coconut milk products fermented by Lactobacillus reuteri LR 92. The best proportion of gums to promote greater viscosity and absence of syneresis of the beverage was 0.15% xanthan gum (w/v) and 0.05% guar gum (w/v). Two products were formulated: fermented coconut milk (FC) and fermented coconut milk with strawberry pulp (FCS). After gastrointestinal simulation, a high survival rate of L. reuteri was found for the products, with 81.63 ± 0.58% for FC and 74.17 ± 1.65% for FCS. In the hedonic acceptance sensory test (total 9 points), the products obtained global scores above 7.5. In the attitude scale test (total 7 points), 5.10 ± 1.28 for FC and 5.48 ± 1.30 for FCS. Among the fatty acids detected, the products had a higher percentage of lauric acid, with values ranging from 37.89 ± 0.89% to 44.45 ± 3.16%. The FC and FCS products showed promising results, indicating that fermented coconut milk beverages are suitable for the development of new functional products with high acceptability by the consumer. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05303-1.

Statistical optimization of exopolysaccharide production by Leuconostoc pseudomesenteroides JF17 from native Atlantic Forest juçara fruit.

Leuconostoc pseudomesenteroides belongs to a group of lactic acid bacteria normally isolated from fruits, which has the capacity to produce exopolysaccharides (EPS). The present study aimed to optimize the EPS production of L. pseudomesenteroides JF17, isolated from juçara fruits (palm trees threatened with extinction in the Atlantic Forest), using the response surface methodology (RSM), besides evaluating the fermentation kinetics. The maximum production of EPS 53.77 mg/mL was obtained under ideal conditions of MRS broth supplemented with sucrose at 18%, w/v, fermentation temperature of 20 °C and initial pH of 7.30. The Luedeking-Piret model suggested that the production of EPS by the JF17 strain appeared to be associated with the cell growth of the microorganism, in addition to having high efficiency in the production of the polysaccharide from the substrate (Yp/s = 17.85 ± 0.74 mg EPS/log CFU ). Thus, the ideal optimization conditions and kinetic parameters can be useful for increasing the scale up of the fermentation process in the industrial production of EPS by L. pseudomesenteroides JF17.

Coconut milk beverage fermented by Lactobacillus reuteri: optimization process and stability during refrigerated storage.

This study aimed to establish the optimal conditions of temperature (31-43 °C) and coconut pulp concentration in water 1:3-1:9 (w/v) for the growth of Lactobacillus reuteri LR 92 or DSM 17938 in coconut milk beverage, using a central composite face centered design. The optimized conditions were used for analysis of the viability during the fermentation process, pH, production of sugars and organic acids by High Performance Liquid Chromatography (HPLC) and reuterin production. Coconut milk provided adequate substrate for L. reuteri growth without supplementation. The optimal parameters for L. reuteri viability were: concentration 1:3 (w/v) and 37 °C for LR 92 and concentration 1:3 (w/v) and 34 °C for DSM 17938. Chemical analysis showed that the naturally occurring sucrose in the matrix (ca. 4.4 g/L) was used for cell multiplication and the strains differed in the production and content of organic acids. After fermentation until pH 4.5 ± 0.1, the samples were stored at 4 °C for 30 days and the final cell viability in coconut milk was 7.55 ± 0.07 log CFU/mL for L. reuteri LR 92 and 8.57 ± 0.09 log CFU/mL for DSM 17938. It was detected 0.15 ± 0.03 mM and 0.14 ± 0.04 mM of reuterin produced by DSM 17938 and LR 92, respectively. L. reuteri DSM 17938 presented a great decrease of pH and post acidification after storage. The LR 92 strain showed low post acidification. These results showed that coconut milk provides adequate matrix for the development of new fermented functional beverages.