Multiobjective response and chemometric approaches to enhance the phytochemicals and biological activities of beetroot leaves: an unexploited organic waste.

Research on medicinal plants is developing each day due to inborn phytochemicals, which can encourage the progress of novel drugs. Most plant-based phytochemicals have valuable effects on well-being. Among them, beetroot leaves (BL) are known for their therapeutic properties. Here, three solvents, namely, acetonitrile, ethanol, and water, and their combinations were developed for BL extraction and simultaneous assessment of phytochemical compounds and antioxidant and antifoodborne pathogen bacteria activities. By using the augmented simplex-centroid mixture design, 40.40% acetonitrile diluted in water at 38.74% and ethanol at 20.86% favored the recovery of 49.28 mg GAE/mL (total phenolic content (TPC)) and 0.314 mg QE/mL (total flavonoid content (TFC)), respectively. Acetonitrile diluted in water at 50% guarantees the best antioxidant activity, whereas the optimal predicted mixture for the highest antibacterial activity matches 24.58, 50.17, and 25.25% of acetonitrile, ethanol, and water, respectively. These extraction conditions ensured inhibition of Staphylococcus aureus, Salmonella enterica, and Escherichia coli, respectively, at 0.402, 0.497, and 0.207 mg/mL. Under optimized conditions, at three concentrations of BL, minimal inhibitory concentration (MIC), 2 × MIC, and 4 × MIC, a linear model was employed to investigate the inhibition behavior against the three tested bacteria. The early logarithmic growth phase of these bacteria illustrated the bactericidal effect of optimized extracted BL with a logarithmic growth phase inferior to 6 h. Therefore, BL extract at 4 × MIC, which corresponds to 1.608, 1.988, and 0.828 mg/mL, was more efficient against S. aureus, S. enterica, and E. coli.

Bioactive Compounds and Pharmacological Potential of Pomegranate (Punica granatum) Seeds - A Review.

The use of complementary medicine has recently increased in an attempt to find effective alternative therapies that reduce the adverse effects of drugs. Pomegranate (Punica granatum L.) by-products, such as seeds, is a rich source of phytochemicals with a high antioxidant activity, thus possessing health benefits. For the identification and quantification of the pomegranate seeds chemical compounds, particular attention has been drawn to the latest developments in the HPLC coupling with electrospray ionization (ESI) MS/MS detection. In fact, a wide range of phytochemicals including phenolic acid, anthocyanins, flavonoids, hydrolysable tannins and other polyphenols were characterized. Furthermore, an exhaustive review of the scientific literature on pomegranate seeds on biomedicine and pharmacotherapy was carried out. Indeed, both in vitro and in vivo studies have demonstrated how pomegranate seeds possess antioxidant, anti- cardiovascular diseases, anti-osteoporosis, antidiabetic, anti-inflammatory and anticancer activities. The present review describes a recent tendency in research focusing on the chemical and biomedical features of the pomegranate seeds to value them as natural additives or active compounds for first-order diseases.

Pomegranate peel as phenolic compounds source: Advanced analytical strategies and practical use in meat products.

The growing demand for natural food preservatives has promoted investigations on their application for preserving perishable foods. Consequently, the meat market is demanding natural antioxidants, free of synthetic additives and able to diminish the oxidation processes in high-fat meat and meat products. In this context, the present review discuss the development of healthier and shelf stable meat products by the successful use of pomegranate peel extracts containing phenolics as natural preservative agent in meat and meat products. This paper carries out an exhaustive review of the scientific literature on the main active phenolic compounds of pomegranate peel identified and quantified by advances in the separation sciences and spectrometry, and its biological activities evaluation. Moreover, the impact of pomegranate peel use on the quality and oxidative stability of meat products is also evaluated. As natural preservative, pomegranate peel phenolics could improve stored meat products quality, namely instrumental color retaining, limitaion of microflora growth, retardation of lipid and protein oxidation.

A novel thermostable and efficient Class II glucose isomerase from the thermophilic Caldicoprobacter algeriensis: Biochemical characterization, molecular investigation, and application in High Fructose Syrup production.

A novel glucose isomerase gene from the thermophilic Caldicoprobacter algeriensis, encoding a polypeptide of 438 residues, was identified, cloned and successfully expressed in E. coli. The purified enzyme (GICA) was a homotetramer of about 200 kDa displaying the highest activity at pH 7.0 and 90 °C and retaining 97% of its maximum activity at pH 6.5. The enzyme showed an excellent thermostability with a half-life of 6 min at 100 °C. Interestingly, GICA had a very high affinity of 40 mM and catalytic efficiency of 194 min-1 mM-1 toward d-glucose at 90 °C. A maximum of 54.7% d-glucose to d-fructose conversion was achieved by GICA at 85 °C making it an attractive candidate for HFCS-55 production. The primary sequence inspection and molecular modeling studies revealed that the thermal stability of GICA could be attributed to the presence of extra charged residues at the surface like E108 and Q408 increasing surface charge interactions. Moreover, a serine at position 56 near to P58 could establish hydrogen bond strengthening the dimer attachment. The high catalytic efficiency and affinity of GICA could be ascribed to the presence of amino acid like E108 and K62 that created more charges around the catalytic site entry.

Geographical Discrimination of Virgin Olive Oils from the Tunisian Coasts by Combining Fatty Acids and Phenolic Acids Profiles within a Multivariate Analysis.

Virgin olive oils extracted from three principal Tunisian olive cultivars (Chemlali, Chetoui and Zarrazi) and coming from four different regions (Sfax, Beja, Gabes and Medenine) along the Tunisian costs were analysed. The quality indices as well as fatty acids and phenolic acids content of oil samples were examined using univariate and multivariate statistical analysis. The finding demonstrated that significant differences (p < 0.05) were found in quality indices between the different cultivars and that fatty acid content is the most informative in discriminating olive oils from production sites that are different by geographical and climatic parameters. In fact, southern cultivars (Zarrazi Gabes and Zarrazi Medenine) have the best fatty acid combination according to their oxidative effect. Besides, phenolic acids content was not useful in discriminating olive oil samples and could depend not only on geographic location but also on olive variety and agronomic practices. Nevertheless, Principal Component Analysis allowed us to highlight the Chemlali Beja olive oil for its interesting oxidative stability, fatty acid composition and its richness in phenolic acids content.

Identification and characterization of single nucleotide polymorphism markers in FADS2 gene associated with olive oil fatty acids composition.

BACKGROUND: Genotyping of the FAD2.1 and FAD2.3 polymorphisms in the fatty acid desaturase 2 gene (FADS2) shows that they are associated with the fatty acids composition of olive oil samples. However, these associations require further confirmation in the Tunisian olive oil cultivars, and little is known about the effect of polymorphisms in fatty acid-related genes on olive oil mono- and poly- unsaturated fatty acids distribution. METHODS: A set of olive oils from 12 Tunisian cultivars was chosen. The fatty acid composition of each olive oil sample was determined by gas chromatography. Statistical and modeling Bayesian analyses were used to assess whether the FAD2.1 and FAD2.3 genotypes were associated with fatty acids composition. RESULTS: The TT-FAD2.1 and the GG-FAD2.3 genotypes were found to be associated with a lower proportion of oleic acid (C18:1) (r = -0.778, p = 0.003; r = -0.781, p= 0.003) as well as higher proportion of linoleic (C18:2) (r = 0.693, p = 0.012; r = -0.759, p= 0.004) and palmitic acids (C16:0) (r = 0.643, p = 0.024; r = -0.503, p= 0.095), making varieties with this haplotype (i.e. Chemlali Sfax and Meski) producing more saturated (C16: 0) and polyunsaturated acids than oleic acid. The latter plays a major role in preventing several diseases. CONCLUSION: The two associations FADS2 FAD2.1 and FADS2 FAD2.3 with the fatty acid compositions of olive oil samples were identified among the studied olive cultivars. These associations differed between studied cultivars, which might explain variability in lipidic composition among them and consequently reflecting genetic diversity through differences in gene expression and biochemical pathways. FADS2 locus would constitute thus a good marker for detecting interesting lipidic chemotypes among commercial olive oils.

Biocatalysts: application and engineering for industrial purposes.

Enzymes are widely applied in various industrial applications and processes, including the food and beverage, animal feed, textile, detergent and medical industries. Enzymes screened from natural origins are often engineered before entering the market place because their native forms do not meet the requirements for industrial application. Protein engineering is concerned with the design and construction of novel enzymes with tailored functional properties, including stability, catalytic activity, reaction product inhibition and substrate specificity. Two broad approaches have been used for enzyme engineering, namely, rational design and directed evolution. The powerful and revolutionary techniques so far developed for protein engineering provide excellent opportunities for the design of industrial enzymes with specific properties and production of high-value products at lower production costs. The present review seeks to highlight the major fields of enzyme application and to provide an updated overview on previous protein engineering studies wherein natural enzymes were modified to meet the operational conditions required for industrial application.

Expression of A. niger US368 xylanase in E. coli: purification, characterization and copper activation.

The XAn11 cDNA was cloned in pET-28a(+) and the recombinant plasmid was transformed in Escherichia coli. The His-tagged r-XAn11 was purified using Ni-NTA affinity and anion exchange chromatography. The enzyme showed a specific activity of 415.1 U mg(-1) and a molecular mass of 25 kDa. It had an optimal activity at pH 5 and 50°C. It was stable in a wide range of pH and in the presence of some detergents and organic solvents. In the presence of 3mM Cu2+, the relative activity of the His-tagged r-XAn11 was enhanced by 54%. This is the first work reporting that copper is a strong activator for xylanase activity making this enzyme very attractive for future industrial applications. Molecular modeling suggests that the contact region between the catalytic site and the N-terminal His-tag fusion peptide could be responsible for the different behavior of the native and recombinant enzyme toward copper.

Effects of parabens and isothiazolinone on the microbiological quality of baby shampoo: the challenge test.

An in vitro microbial challenge test has been developed to predict the likelihood of consumer contamination of baby shampoo. Four preservatives were tested in our study: the parbens Medcide D, Medcide PB, Sepicide HB. and isothiazolinone Methylisothiazolinone/Chloromethylisothiazolinone [MI/MCI]. These preservatives were tested separately and in combination. The challenge test involved inoculating the product with Micrococcus luteus, Staphylococcus aureus, Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Aspergillus brasiliensis and Candida albicans. Inhibition growth of these microorganisms at each preservative concentration was followed over a 28 d period. The test was used to classify products as poorly preserved, marginally preserved, or well-preserved. Interestingly, it was the combination (0.1% Isothiazolinone [MI/MCI] and 0.1% Sepicide HB) which inhibited most the microbial growth of microorganims while preserving the physicochemical properties of the product. As a result, the challenge test described can be accurately used to predict the risk of consumer contamination of cosmetic products.

Engineered glucose isomerase from Streptomyces sp. SK is resistant to Ca²âº inhibition and Co²âº independent.

The role of two amino acid residues linked to the two catalytic histidines His54 and His220 in kinetics and physicochemical properties of the Streptomyces sp. SK glucose isomerase (SKGI) was investigated by site-directed mutagenesis and molecular modeling. Two single mutations, F53L and G219D, and a double mutation F53L/G219D was introduced into the xylA SKGI gene. The F53L mutation increases the thermostability and the catalytic efficiency and also slightly shifts the optimum pH from 6.5 to 7, but displays a profile being similar to that of the wild-type enzyme concerning the effect of various metal ions. The G219D mutant is resistant to calcium inhibition retaining about 80% of its residual activity in 10 mM Ca²âº instead of 10% for the wild-type. This variant is activated by Mn²âº ions, but not Co²âº, as seen for the wild-type enzyme. It does not require the latter for its thermostability, but has its half-life time displaced from 50 to 20 min at 85°C. The double mutation F53L/G219D restores the thermostability as seen for the wild-type enzyme while maintaining the resistance to the calcium inhibition. Molecular modeling suggests that the increase in thermostability is due to new hydrophobic interactions stabilizing α2 helix and that the resistance to calcium inhibition is a result of narrowing the binding site of catalytic ion.