Application of response surface methodology to laser-induced breakdown spectroscopy : influences of hardware configuration

Response Surface Methodology (RSM) was employed to optimise LIBS analysis of single crystal silicon at atmospheric pressure and under vacuum conditions (pressure ~10-6mbar). Multivariate analysis software (StatGraphics 5.1) was used to design and analyse several multi-level, full factorial RSM experiments. A Quality Factor (QF) was conceived as the response parameter for the experiments, representing the quality of the LIBS spectrum captured for a given hardware configuration. The QF enabled the hardware configuration to be adjusted so that a best compromise between resolution, signal intensity and signal noise could be achieved. The effect on the QF of simultaneously adjusting spectrometer gain, gate delay, gate width, lens position and spectrometer slit width was investigated, and the conditions yielding the best QF determined

Antioxidant Properties of the Methanol Extract of the Wood and Pericarp of Caesalpinia decapetala

The antioxidant activities of the methanol extracts from the wood and pericarp of Caesalpinia decapetala (Roth) Alston (Caesalpiniaceae) were assessed in efforts to validate the herb. The antioxidant activity of the plant has been studied using its ability to scavenger DPPH, superoxide radicals, and nitric oxide radical along with its ability to inhibit lipid peroxidation. The antioxidant activity and phenolic content of the pericarp as determined by the DPPH, superoxide radical, nitric oxide radical, total phenols, the flavonoids, and total flavonols were higher than that of the wood. Analysis of plant extracts revealed a high amount of polyphenols and flavonoids suggesting a possible role of these phytoconstituents in the antioxidant property. Moreover, the results were observed in a concentration and dose dependent manner. Studies clearly indicate that the C. decapetala has significant antioxidant activity

Response surface optimisation for the extraction of phenolics and flavonoids from a pink guava puree industrial by-product

Pink guava puree industry produces huge amount of by-products that have potential as sources for polyphenols. Response surface methodology was implemented to optimise the extraction conditions for phenolics (Y1) and flavonoids (Y2) from a by-product of the guava industry. A three-factor inscribed central composite design was employed to determine the effects of three independent variables, namely pH (X1: 2-6), temperature (X2: 40-60 °C) and time (X3: 1-5 h), on the response variables. The corresponding predicted values for phenolics and flavonoids were 336.30 and 427.35 mg 100 g-1, respectively. Predicted values for extraction rates of phenolics agreed well with experiment values; R2 of 0.902. However, the model derived for flavonoids extraction was less reliable; R2 of 0.983. Increase in time and temperature was found significant in increasing the extraction rate. The optimum conditions for extracting phenolics by ethanolic solvent occurred at a pH of 2 and 60 °C for a 5-h extraction

Bio-augmentation of antioxidants and phenolic content of Lablab purpureus by solid state fermentation with GRAS filamentous fungi

The present study was conducted to find out the effect of solid state fermentation on release of phenolics and subsequently on improvement of antioxidant activity of fermented seed and flour of Lablab purpureus (seim), using GRAS filamentous fungi i.e. Aspergillus awamori and Aspergillus oryzae. Significant increase in TPC level was observed on 5th day of fermentation of seed and flour with A. awamori and A. oryzae as compared to non-fermented ones. In DPPH and ABTS antioxidant assay, maximum activity was noticed in fermented ethanolic extract of seim seed with A. awamori and A. oryzae on 3rd and 4th day of incubation, respectively. The findings showed higher antioxidant activity formation in fermented seim seed than flour. Significant increase in enzyme activity of α-amylase was also contributed by SSF. This study demonstrated that fermented seed and flour of seim are better source of phytochemicals compared to the non-fermented ones

Optimization of extraction conditions and enhancement of phenolic content and antioxidant activity of pearl millet fermented with Aspergillus awamori MTCC-548

AbstractThe present study envisaged two stage optimization of conditions using RSM for extraction of total phenolic compounds from pearl millet koji prepared with Aspergillus awamori. Antioxidant activity was determined by employing DPPH and radical cation of ABTS. In phase-1, fermentation time (5–8 days), extraction temperature (40–60 °C), extraction time (45–60 min.) and solvent (ethanol, 50%; 0.5 ml HCL + 99.5 ml methanol) were tested for maximizing extraction process. The optimum conditions of phenolic recovery were achieved at 8 days fermentation time, 40 °C extraction temperature, 45 min. extraction time with 50% ethanol as solvent, with values of 169.19 mg GAE/g for TPC, 262.7 VCEAC µmol/g for DPPH and 281.86 VCEAC µmol/g for ABTS. TPC were found to be positively correlated (p < 0.05) with DPPH and ABTS under these conditions. In phase-2, a central composite design was applied for design of experiments and model building using extraction time and extraction temperature as process variables for further maximizing the extraction of TPC. The optimized conditions using RSM for maximizing the extraction of total phenolic compounds were: ethanol concentration, 50%; extraction temperature, 44.5 °C and extraction time, 23.8 mins. Under these conditions, 176.82 mg GAE/g of total phenolic compounds were extracted which was very close to the predicted value of 173.2 mg GAE/g. The model was validated at these optimal points

Bio-enrichment of phenolics and antioxidant activity of combination of Oryza sativa and Lablab purpureus fermented with GRAS filamentous fungi

Cereal and legumes meet a considerable requirement of protein and carbohydrate of the local population. Most of the foods are cereal based but some cereal/legume or legume based foods are also common in many countries of Asia and Africa. In present study, the effect of fermentation on total phenolics, antioxidant activity and α-amylase enzyme activity of ethanolic extracts of each of seeds and flours combination (1:1) of Oryza sativa (rice) and Lablab purpureus (seim) was determined. The percentage inhibition of free radicals formation by DPPH and ABTS assays was found maximum i.e. 80.66 ± 0.21, 97.67 ± 0.35 on 4th day of incubation of combined sample of rice and seim seeds fermented with Aspergillus oryzae and Aspergillus awamori, respectively. The increased percentage inhibition of free radical formation of fermented samples was found greater than the non-fermented samples (65.88 ± 0.15, 42.00 ± 0.63). The TPC of substrate i.e. rice:seim seeds (1:1) was also found maximum i.e. 47.53 ± 0.20 on 5th day of fermentation with A. awamori. α-amylase activity of fermented samples was also found higher than that of non fermented samples. Almost similar results were obtained in combined flour extract of both the substrates. Increase in level of α-amylase enzyme during SSF indicates that enzymes produced by microorganisms were responsible for release of bound phenolics which may be responsible for increase in antoxidant activity of extracts of fermented seeds and flour combination a cereal and a legume

Application of headspace solid-phase microextraction and gas chromatography for the analysis of furfural in crude palm oil

Processing of vegetative material containing pentoses has been shown to result in the formation of furfural. Furfural exhibits a spectrophotometric absorption peak at 518 nm when complexed with aniline acetate. Headspace solid-phase microextraction (HS-SPME) method has been successfully used to confirm the presence of furfural in crude palm oil (CPO). Solid phase microextraction (SPME) fiber composed of divinylbenzene/Carboxen/polydimethylsiloxane (DVB/PDMS/CAR) was used to absorb the volatiles in the headspace of the oil. The isolated compounds from the fiber was desorbed and separated on a capillary polar column of a gas chromatograph. Response surface methodology (RSM) was used to optimize the SPME fiber condition for maximum absorption of furfural from CPO. The optimized temperature and time for furfural extraction onto the SPME fiber are 70 °C for 40 min. Oils obtained from the mill were found to contain between 2 and 13% furfural

Polyphenolic compounds and anthocyanin content of Prosopis nigra and Prosopis alba pods flour and their antioxidant and anti-inflammatory capacities

The aim of this study was to determine the content of total free and bound phenolic, free and bound flavonoid, anthocyanin, alkaloid and the profiles of polyphenols of the edible ripe pods of Prosopis alba and Prosopis nigra. P. alba flour showed significantly higher total (sum of Free- and Bound) phenolic content and total flavonoid compounds than P. nigra (P < 0.05) while P. nigra had higher concentrations of anthocyanins than P. alba (P < 0.05). The P. nigra flour shows a pattern characterized by the occurrence of anthocyanins (principally cyanidin-3-glucoside) as well as 14 flavonoid glycosides, with higher chemical diversity than P. alba, who shows 8 flavonoid glycosides as relevant constituents. The main compounds were quercetin O-glycosides and apigenin-based C-glycosides. The phenolic composition of two South American algarrobo pod flour is presented for the first time. The colour of the algarrobo pods is related to the content of anthocyanins. P. nigra pods having higher content of anthocyanins are darker (purple) than those of P. alba (light brown). Furthermore, the free sugar polyphenolic extracts of P. nigra and P. alba (phenolic-enriched Amberlite-retained fraction) as well as anthocyanins enriched extracts from P. nigra showed free radical scavenging activity. The P. nigra polyphenolic extracts showed activity against a pro-inflammatory enzyme (cyclooxygenase). In conclusion, algarrobo pods meal differing in colour contained biologicall active polyphenols, with possible positive impact in human health.Fil: Perez, Maria Jorgelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Cuello, Ana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Zampini, Iris Catiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Ordóñez, Roxana Mabel. Universidad Nacional de Tucuman. Facultad de Cs.naturales E Instituto Miguel Lillo. Catedra de Quimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; ArgentinaFil: Alberto, Maria Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Quispe, Cristina. Universidad de Talca; ChileFil: Schmeda Hirschmann, Guillermo. Universidad de Talca; ChileFil: Isla, Maria Ines. Universidad Nacional de Tucuman. Facultad de Cs.naturales E Instituto Miguel Lillo. Catedra de Quimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentin

Properties of Bread Dough with Added Fiber Polysaccharides and Phenolic Antioxidants: A Review

During breadmaking, different ingredients are used to ensure the development of a continuous protein network that is essential for bread quality. Interests in incorporating bioactive ingredients such as dietary fiber (DF) and phenolic antioxidants into popular foods such as bread have grown rapidly, due to the increased consumer health awareness. The added bioactive ingredients may or may not promote the protein cross-links. Appropriate cross-links among wheat proteins, fiber polysaccharides, and phenolic antioxidants could be the most critical factor for bread dough enhanced with DF and phenolic antioxidants. Such cross-links may influence the structure and properties of a bread system during baking. This article presents a brief overview of our current knowledge of the fate of the key components (wheat proteins, fibers, and phenolic antioxidants) and how they might interact during bread dough development and baking