Multivariate optimization results in an edible extract from Ilex paraguariensis unexplored residues with a high amount of phenolic compounds.

Ilex paraguariensis A. St. Hil. plants are used for the preparation of food and drinks which are widely consumed worldwide. During the harvest season of these plants, 2-5 ton hec-1 of agricultural residue is generated, which remains underutilized. Therefore, this study aimed to obtain an edible extract with high content of bioactive compounds and antimicrobial properties from the agricultural residue of I. paraguariensis for industrial use in food applications. The extraction conditions were optimized through a multivariate experimental design using ethanol:water. The extracted compounds were characterized by HPLC-ESY-QTOF-MS. In the optimal extraction conditions, 55 compounds were extracted, including 8 compounds that were not previously reported in I. paraguariensis. The method proved to be simple, fast, economical and environmentally friendly, with the use of green solvents. This optimization allowed for the extraction of 15.07 g of phenolic compounds per 100 g of residue. The extract showed high antioxidant activity and the capacity to inhibit Staphylococcus aureus. Results indicate that it is possible to obtain an edible extract with a high content of bioactive compounds, particularly phenolic compounds, from the I. paraguariensis residue, which has high prospects for the valorization of unexplored natural resources.

In Vitro Probiotic and Antioxidant Potential of Lactococcus lactis subsp. cremoris LL95 and Its Effect in Mice Behaviour.

The composition of intestinal microbiota is widely believed to not only affect gut health but also influence behaviour. This study aimed to evaluate the probiotic characteristics, antioxidant activity, and antidepressant- and anxiolytic-like activities of Lactococcus lactis subsp. cremoris LL95. This strain showed probiotic properties such as resistance in a simulated gastric tract model and survival at different concentrations of NaCl and bile salts. Moreover, antioxidant activity of LL95 was demonstrated through DPPH radical scavenging activity, scavenging of ABTS•+ radical and ferric ion reducing antioxidant power (FRAP) assays. Female C57BL/6 mice received LL95 orally at a dose of 109 UFC/day for 28 days. LL95 improved depressive- and anxiety-like behaviour, demonstrated by decreased immobility time in the tail suspension test and forced swim test and increased per cent of time spent in the open arms on the elevated plus maze. These findings indicate the potential antioxidant activity of LL95 and its role in behaviour, suggesting that probiotic may have therapeutic applications.

Attached and planktonic Listeria monocytogenes global proteomic responses and associated influence of strain genetics and temperature.

Contamination of industrial and domestic food usage environments by the attachement of bacterial food-borne pathogen Listeria monocytogenes has public health and economic implications. Comprehensive proteomics experiments using label-free liquid chromatography/tandem mass spectrometry were used to compare the proteomes of two different L. monocytogenes strains (Siliken_1/2c and F2365_4b), which show very different capacities to attach to surfaces. Growth temperature and strain type were highly influential on the proteomes in both attached and planktonic cells. On the basis of the proteomic data, it is highly unlikely that specific surface proteins play a direct role in adherence to inanimate surfaces. Instead, strain-dependent responses related to cell envelope polymer biosynthesis and stress response regulation likely contribute to a different ability to attach and also to survive external stressors. Collectively, the divergent proteome-level responses observed define strain- and growth-temperature-dependent differences relevant to attachment efficacy, highlight relevant proteins involved in stress protection in attached cells, and suggest that strain differences and growth conditions are important in relation to environmental persistence.

Highly specific fiber optic immunosensor coupled with immunomagnetic separation for detection of low levels of Listeria monocytogenes and L. ivanovii.

BACKGROUND: Immunomagnetic separation (IMS) and immunoassays are widely used for pathogen detection. However, novel technology platforms with highly selective antibodies are essential to improve detection sensitivity, specificity and performance. In this study, monoclonal antibodies (MAbs) against Internalin A (InlA) and p30 were generated and used on paramagnetic beads of varying diameters for concentration, as well as on fiber-optic sensor for detection. RESULTS: Anti-InlA MAb-2D12 (IgG2a subclass) was specific for Listeria monocytogenes and L. ivanovii, and p30-specific MAb-3F8 (IgM) was specific for the genus Listeria. At all bacterial concentrations (10³-108 CFU/mL) tested in the IMS assay; the 1-µm diameter MyOne beads had significantly higher capture efficiency (P < 0.05) than the 2.8-µm diameter M-280 beads with both antibodies. The highest capture efficiency for MyOne-2D12 (49.2% for 105 CFU/mL) was significantly higher (P < 0.05) than that of MyOne-3F8 (16.6 %) and Dynabeads anti-Listeria antibody (9 %). Furthermore, capture efficiency for MyOne-2D12 was highly specific for L. monocytogenes and L. ivanovii. Subsequently, we captured L. monocytogenes by MyOne-2D12 and MyOne-3F8 from hotdogs inoculated with mono- or co-cultures of L. monocytogenes and L. innocua (10-40 CFU/g), enriched for 18 h and detected by fiber-optic sensor and confirmed by plating, light-scattering, and qPCR assays. The detection limit for L. monocytogenes and L. ivanovii by the fiber-optic immunosensor was 3 × 10² CFU/mL using MAb-2D12 as capture and reporter antibody. Selective media plating, light-scattering, and qPCR assays confirmed the IMS and fiber-optic results. CONCLUSIONS: IMS coupled with a fiber-optic sensor using anti-InlA MAb is highly specific for L. monocytogenes and L. ivanovii and enabled detection of these pathogens at low levels from buffer or food.