Search results for "Chemical Engineering"

Enzyme inactivation and evaluation of physicochemical properties, sugar and phenolic profile changes in cloudy apple juices after high pressure proce…

2019

The effect of high pressure processing (HPP) (200–600 MPa/5–45°C/1–15 min) on the enzyme activity and some quality parameters of cloudy apple juice during subsequent storage (4°C for 12 weeks) was investigated. Statistical analysis showed that pressure, temperature, and time had a significant effect (p < 0.05) on tissue enzyme activity, decreasing the activity of polyphenol oxidases (PPO) and peroxidases (POD). No significant changes in physicochemical parameters (pH, total soluble solids, sugars, and vitamin C) were observed after HPP treatments. The main polyphenols detected in apple juice were dichydrochalcones, being phloridzin the predominant (48.8 mg/L), and flavanols, with the highes…

Evaluation of microbiological and physico‐chemical parameters of retail ready‐to‐eat mono‐varietal salads

2019

An integrated microbiological and physico-chemical approach was applied to evaluate the decay of mono-varietal ready-to-eat escarole (Cichorium endivia var. latifolium) and red chicory (Cichorium intybus L. var. foliosum Hegi) during refrigeration. Total mesophilic microorganisms, including pseudomonads, and total psychrotrophic microorganisms were detected at high numbers in all samples just after packaging and at the expiry date. The dominant microbial populations analyzed by classical culture-dependent methods belonged to Pseudomonas and yeasts. Illumina sequencing identified Janthinobacterium lividum and Pseudomonas veronii as main species. Regarding the physico-chemical quality between…

Interaction of Oily Water with Floating Porous Ceramic and Immobilized Microorganisms

2018

Oily water was treated with porous ceramic granules and immobilized microorganisms. Floating granules with bulk density of 0.63-0.66 g cm-3were used. The sorption of motor oil was investigated for dry and wetted granules. Respiration experiments showed that microorganisms immobilized on floating ceramic carrier and treated with oily water were influenced by agitation of liquid. The treatment of oily water with low salinity (1-9 g L-1) showed that oil removal efficiency decreased after increasing water salinity. Likewise, oil removal efficiency decreased from 12 to 9% per gram of ceramic carrier after increasing the spill of oil from 9 to 35 g per square meter. Porous granules with immobiliz…

Evaluating the impact of vegetal and microalgae protein sources on proximate composition, amino acid profile, and physicochemical properties of ferme…

2018

Influence of pulsed electric field processing on the quality of fruit juice beverages sweetened with Stevia rebaudiana

2017

Abstract A fruit juice-stevia beverage was processed using pulsed electric fields (PEF), a non-thermal preservation technology, with the purpose of investigating the feasibility of PEF for bioactive compounds and steviol glycosides enhancement and its impact on physicochemical properties. Variable ranges of response surface methodology were 20–40 kV/cm (electric field strength), 100–360 μs (treatment time) and 0–2.5% (w/v) stevia. After PEF, ascorbic acid was retained by more than 74%. Some of the analyzed PEF treatments resulted in an enhancement of total anthocyanins and carotenoids. The best results for rebaudioside A/stevioside ratio were obtained when PEF was applied at 30 kV/cm for 23…

Effect of Enzyme Amounts Used in Gastrointestinal Digestion Upon Solubility and Caco-2 Cell Uptake Assays of Minerals from Infant Formulas

2005

The effect of enzyme amounts used in gastrointestinal in vitro digestion upon the solubility and Caco-2 cell uptake of calcium, iron and zinc from infant formulas (IFs) was studied. Different amounts of enzymes (g enzyme/g IF), pepsin (0.002 and 0.048), pancreatin (0.0005, 0.002 and 0.01) and bile extract (0.003, 0.125 and 0.0625) were assayed. Mineral soluble contents and mineral uptakes by Caco-2 cells were affected by the enzyme amounts used in digestion. Although the highest mineral solubility (Ca 98.6 vs 46.2%; Fe 98.1 vs 83.9%; Zn 98.4 vs 83%) was obtained when the lowest enzyme (pepsin 0.002 vs 0.048; pancreatin 0.0005 vs 0.01g/g IF) and bile extract (0.003 vs 0.0625g/g IF) amounts …

Improvement of Analytical Conditions of Mineral Caco-2 Cell Uptake Assays

2004

Caco-2 cell mineral uptake assays are used to estimate the bioavailability of minerals from foods. The uptake of minerals by Caco-2 cells can be affected by several factors – particularly the conditions of the in vitro digestion process and the growth conditions of the cell culture. Therefore, a standardisation of the assays conditions is required to obtain reproducible results. This work determined the effect of enzyme demineralisation, the inactivation of the proteolytic activity of the digest and the replacement of distilled-deionised water by cell culture degree water. Treatment with Chelex-100 resin was applied to remove calcium, iron and zinc from pepsin and pancreatin-bile salts. Th…

Antifungal activity and shelf life extension of loaf bread produced with sourdough fermented by Lactobacillus strains

2019

The objective of this study was to evaluate a water‐soluble extract from sourdoughs fermented with the lactic acid bacteria (LAB) for antifungal reflect on loaf bread. The extracts produced by Lactobacillus plantarum CECT 749 and L. bulgaricus CECT 4005 were effective against strains of Fusarium spp., Penicillium spp., and Aspergillus spp., with minimum inhibitory concentration ranging from 1.6 to 200 mg/ml and minimum fungicidal concentration from 1.6 to 400 mg/ml. LC‐ESI‐MS‐TOF was used to analyze the antimicrobial compounds. Several antimicrobial phenolic acids were found. Fermented sourdoughs used for the production of loaf bread produced a reduction of fungal growth in relation on the …

Modelling binary mixtures of herbicides in populations resistant to one of the components: evaluation for resistance management

2008

BACKGROUND: Herbicide mixtures are commonly proposed to delay the selection of herbicide resistance in susceptible populations (called the SM strategy). However, in practice, herbicide mixtures are often used when resistance to one of the two active ingredients has already been detected in the targeted population (called the RM strategy). It is doubtful whether such a practice can select against resistance, as the corresponding selection pressure is still exerted. As a consequence, the effect of mixtures on the evolution of an already detected resistance to one of the herbicides in the combination remains largely unexplored. In the present work, a simple model was developed to explore furth…

Antiviral and antioxidant properties of active alginate edible films containing phenolic extracts

2018

In this work, novel active edible films having antiviral activity were developed through the solvent casting method. Emulsified edible films were prepared by adding lipids into alginate films in order to improve their water vapour permeability. In addition, two natural extracts rich in phenolic compounds, specifically a green tea extract (GTE) and a grape seed extract (GSE) were used as active agents. Interestingly, incorporating GTE or GSE within the biopolymer matrix, the films exhibited significant antiviral activity against murine norovirus (MNV) and hepatitis A virus (HAV) since ∼2 log reduction were recorded for the 0.75 g extract/g alginate in the film, being GTE more efficient than …