Potato peels waste as a sustainable source for biotechnological production of biofuels: Process optimization.

Potato peel waste (PPW) is a starchy by-product generated in great amounts during the industrial processing of potatoes. It can be used as a low cost alternative, and renewable feedstock for the production of second generation bioethanol. In order to intensify this process, Saccharomyces cerevisiae Ethanol Red®, a robust and thermotolerant yeast strain, was selected and two experimental designs and response surfaces assessment were conducted to enable very high gravity fermentations (VHGF) using PPW as feedstock. The first one focused on the optimization of the liquefaction and enzymatic hydrolysis stages, enabling a maximum ethanol concentration of 116.5 g/L and a yield of 80.4 % at 72 h of fermentation; whereas, the second one, focus on the optimization of the pre-saccharification and fermentation stages, which further increased process productivity, leading to a maximum ethanol concentration of 108.8 g/L and a yield of 75.1 % after 54 h of fermentation. These results allowed the definition of an intensified pre-saccharification and simultaneous saccharification and fermentation (PSSF) process for ethanol production from PPW, resorting to short liquefaction and pre-saccharification times, 2 h and 10 h respectively, at an enzyme loading of 80 U/g PPW of Viscozyme and 5 UE/g PPW of SAN Super and a higher fermentation temperature of 34 °C due to the use of a thermotolerant yeast. Overall, with these conditions and solely from PPW without any supplementation, the outlined PSSF process allowed reaching a high ethanol concentration and yield (104.1 g/L and 71.9 %, respectively) standing at high productivities with only 54 h of fermentation.

Recent advances in the production of oligogalacturonides and their biological properties.

The human population is becoming old and ageing, which is related to a variety of health issues, such as Alzheimers disease, obesity, diabetes, hypercholesterolemia, and some types of cancers like colorectal cancer. Furthermore, diet is a determining factor in the appearance of some of these diseases due to its direct effect at the systemic level (for instance, increase in glucose and LDL-cholesterol levels in the serum) and its influence on the composition and activity of the gut microbiota. In this context, the use of functional ingredients can be a useful strategy to prevent or even treat (in combination with drugs) some of the above-mentioned pathologies. Among the variety of functional ingredients, prebiotics have received significant attention by the scientific community. Although the already commercialized FOS are the most studied prebiotics, some efforts have been devoted to the search and evaluation of new prebiotic candidates with additional properties. In particular, in the last decade, a variety of in vitro and in vivo assays have been carried out using well isolated and characterized oligogalacturonides, demonstrating that some of them have interesting biological properties, including anticancer, antioxidant, antilipidemic, anti-obesity and anti-inflammatory activities besides prebiotic effects. This work reviews the scientific literature published recently on the production of oligogalacturonides with a special focus on their biological properties.

Recovery of High Value-Added Compounds from Food By-Product.

The agri-food industry generates large quantities of by-products, both of animal and vegetable origin, which are currently discarded or destined to low-value-added applications [...].

Identification and Recovery of Valuable Bioactive Compounds from Potato Peels: A Comprehensive Review.

Nowadays, the potato is one of the most cultivated and consumed food crops in the world and, in recent years, its production has experienced a sharp increase. Its industrial processing generates several by-products that are wasted and cause economic and environmental problems. Among them, potato peel stands out, representing up to 10% of the total potato residues obtained in the processing. On the other hand, these wastes, in addition to presenting antioxidant compounds, are rich in interesting chemical compounds of great value in a biorefinery model. This review summarizes the main compounds present in potato skins as well as the most used and innovative extraction methods employed for their isolation, with special emphasis on the fractions with biological activities. In addition, a sustainable biorefinery proposal focused on obtaining high added-value products with potential applications in the pharmaceutical, food, nutraceutical, or cosmetic industries is included.

Exploiting the Potential of Bioactive Molecules Extracted by Ultrasounds from Avocado Peels-Food and Nutraceutical Applications.

Natural bioactive compounds from food waste have fomented interest in food and pharmaceutical industries for the past decade. In this work, it purposed the recovery of bioactive avocado peel extract using an environmentally friendly technique: the ultrasound assisted extraction. The response surface methodology was applied in order to optimize the conditions of the extraction, ethanol-water mixtures and time. The optimized extracts (ethanol 38.46%, 44.06 min, and 50 °C) were chemically characterized by HPLC-ESI-MS and FTIR. Its antioxidant ability, as well as, its effect on cell metabolic activity of normal (L929) and cancer (Caco-2, A549 and HeLa) cell lines were assessed. Aqueous ethanol extracts presented a high content in bioactive compounds with high antioxidant potential. The most representative class of the phenolic compounds found in the avocado peel extract were phenolic acids, such as hydroxybenzoic and hydroxycinnamic acids. Another important chemical group detected were the flavonoids, such as flavanols, flavanonols, flavones, flavanones and chalcone, phenylethanoids and lignans. In terms of its influence on the metabolic activity of normal and cancer cell lines, the extract does not significantly affect normal cells. On the other hand, it can negatively affect cancer cells, particularly HeLa cells. These results clearly demonstrated that ultrasound is a sustainable extraction technique, resulting in extracts with low toxicity in normal cells and with potential application in food, pharmaceutical or nutraceutical sectors.

Environmentally Friendly Hydrothermal Processing of Melon by-Products for the Recovery of Bioactive Pectic-Oligosaccharides.

Melon by-products, that currently lack high value-added applications, could be a sustainable source of bioactive compounds such as polysaccharides and antioxidants. In this work, melon peels were extracted with water to remove free sugars, and the water-insoluble solids (WISs) were subjected to hydrothermal processing. The effect of temperature on the composition of the obtained liquors and their total phenolic content was evaluated. The selected liquors were also characterized by matrix assisted laser desorption/ionization-time of flight mass spectroscopy (MALDI-TOF MS), fourier transform infrared spectroscopy (FTIR) and high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), and its phenolic compounds were identified and quantified by high-performance liquid chromatography-diode array detector-tandem mass spectrometry (HPLC-DAD-MS/MS). In addition, the spent solids from the hydrothermal treatment were characterized and their potential use was assessed. At the optimal conditions of 140 °C (severity 2.03), the total oligosaccharide yield accounted for 15.24 g/100 g WIS, of which 10.07 g/100 g WIS were oligogalacturonides. The structural characterization confirmed the presence of partially methyl esterified oligogalacturonides with a wide range of polymerization degrees. After precipitation, 16.59 g/100 g WIS of pectin were recovered, with a galacturonic acid content of 55.41% and high linearity.

Recovery of high value-added compounds from pineapple, melon, watermelon and pumpkin processing by-products: An overview.

Nowadays, fruit and vegetable industries generate huge amounts of under-utilized by-products with a great economic potential. The processing by-products account from 25 up to 60% of the weight of the fruit and would be mainly made of skin and lower percentages of pulp and seeds. All their fractions present an interesting chemical composition and therefore, they could be considered as raw materials for the development of integrated biorefinery approaches. Since, several functional molecules and platform chemicals could be produced by sequential environmentally friendly processes with novel applications in the food, pharmaceutical and cosmetic industries. This review describes the current status of the research dealing with pineapple, melon, watermelon and pumpkin processing by-products, including aspects related to the technologies employed to obtain and isolate high added-value compounds from these by-products. Furthermore, a suitable biorefinery approach for their integral valorisation based on obtaining valuable multi-products is also proposed.

Evaluating environmental parameters for minimum ammonium losses during composting of trimming residues.

A neural fuzzy system was used to investigate the influence of environmental variables (time, aeration, moisture, and particle size) on composting parameters (pH, organic matter [OM], nitrogen [N], ammonium nitrogen [NH4(+)-N] and nitrate nitrogen [NO3(-)-N]). This was to determine the best composting conditions to ensure the maximum quality on the composts obtained with the minimum ammonium losses. A central composite experimental design was used to obtain the neural fuzzy model for each dependent variable. These models, consisting of the four independent process variables, were found to accurately describe the composting process (the differences between the experimental values and those estimated by using the equations never exceeded 5-10% of the former). Results of the modeling showed that creating a product with acceptable chemical properties (pH, NH4(+)-N and NO3(-)-N) entails operating at medium moisture content (55%) and medium to high particle size (3-5 cm). Moderate to low aeration (0.2 L air/min m kg) would be the best compromise to compost this residue because of the scant statistical influence of this independent variable.

SSF production of lactic acid from cellulosic biosludges.

The use of cellulosic biosludges generated in a Kraft pulp mill was investigated as substrate for lactic acid production by simultaneous saccharification and fermentation (SSF). The effect of the operation mode (batch or fedbatch), the initial liquid to solid ratio (12 or 30 g/g) and the nutrient supplementation (MRS components or none) on several parameters including lactic acid concentration, volumetric productivity and product yields, were evaluated. When the operation was carried out in fedbatch mode with nutrient supplementation and using a LSR(0)=12 g/g, a broth containing 42 g/L was obtained after 48 h with a volumetric productivity of 0.87 g/L h and a product yield of 37.8 g lactic acid/100 g biosludges. In a similar experiment carried out without nutrient supplementation, a lactic acid concentration of 39.4 g/L was obtained after 48 h with a volumetric productivity of 0.82 g/L h and a product yield of 35.5 g L-lactic acid/100 g biosludges.

L-lactic acid production from apple pomace by sequential hydrolysis and fermentation.

The potential of apple pomace (a solid waste from cider and apple juice making factories) as a source of sugars and other compounds for fermentation was evaluated. The effect of the cellulase-to-solid ratio (CSR) and the liquor-to-solid ratio (LSR) on the kinetics of glucose and total monosaccharide generation was studied. Mathematical models suitable for reproducing and predicting the hydrolyzate composition were developed. When samples of apple pomace were subjected to enzymatic hydrolysis, the glucose and fructose present in the raw material as free monosaccharides were extracted at the beginning of the process. Using low cellulase and cellobiase charges (8.5 FPU/g-solid and 8.5 IU/g-solid, respectively), 79% of total glucan was saccharified after 12 h, leading to solutions containing up to 43.8 g monosaccharides/L (glucose, 22.8 g/L; fructose, 14.8 g/L; xylose+mannose+galactose, 2.5 g/L; arabinose+rhamnose, 2.8g/L). These results correspond to a monosaccharide/cellulase ratio of 0.06 g/FPU and to a volumetric productivity of 3.65 g of monosaccharides/L h. Liquors obtained under these conditions were used for fermentative lactic acid production with Lactobacillus rhamnosus CECT-288, leading to media containing up to 32.5 g/L of L-lactic acid after 6 h (volumetric productivity=5.41 g/L h, product yield=0.88 g/g).

Valorization of peanut shells: Manufacture of bioactive oligosaccharides.

Peanut shells were subjected to non-isothermal aqueous treatments to cause the partial breakdown of hemicelluloses into soluble oligosaccharides and lignin-derived compounds with high antioxidant activity. The effects of temperature on the chemical composition of the substrate and soluble reaction products were assessed. Under selected conditions (210°C, severity=4.09), the overall amount of poly- and oligo- saccharides present in the liquid phase reached 9.8g/L. This solution was refined by consecutive stages of discontinuous diafiltration, yielding a refined product containing about 72.4wt% of oligomers at a global yield of 8.5kg/100kg oven-dry PS. The purified products were characterized by HPLC, MALDI-TOF-MS and FTIR, confirming the major reaction products were saccharides made up of xylose with degrees of polymerization up to 17, substituted with acetyl and methylglucuronosyl groups, for which a number of pharmaceutical and food applications have been proposed. Solubilization of hemicelluloses in the treatments resulted in the production of solids enriched in cellulose and lignin suitable for further applications.

Modelling the isothermal degradation kinetics of metrafenone and mepanipyrim in a grape juice analog.

Five photodegradation products of metrafenone (MTF) and six of mepanipyrim (MEP) were identified in synthetic grape juice at 25 °C and the structures of the main reaction products established. The degradation of MTF and MEP was modelled by using three different strategies involving monitoring (a) the disappearance of the parent compound, (b) the conversion of the parent compound into its main structurally related reaction products and (c) the degradation of the parent compound to all intermediates and degradation end-products. The kinetic coefficients of degradation for these fungicides were determined and the corresponding half-lives found to be 20.8 h for MFT and 10.1 h for MEP. The proposed models afford reasonably accurate interpretation of the experimental data. Based on the results, modelling the kinetics of disappearance of the parent compound by itself does not ensure the best fit of the degradation behaviour of the fungicides.

Use of safety devices and the prevention of percutaneous injuries among healthcare workers.

OBJECTIVE: To study the effectiveness of safety devices intended to prevent percutaneous injuries.Design. Quasi-experimental trial with before-and-after intervention evaluation. SETTING: A 350-bed general hospital that has had an ongoing educational program for the prevention of percutaneous injuries since January 2002. METHODS: In October 2005, we implemented a program for the use of engineered devices to prevent percutaneous injury in the emergency department and half of the hospital wards during the following procedures: intravascular catheterization, vacuum phlebotomy, blood-gas sampling, finger-stick blood sampling, and intramuscular and subcutaneous injections. The nurses in the wards that participated in the intervention received a 3-hour course on occupationally acquired bloodborne infections, and they had a 2-hour "hands-on" training session with the devices. We studied the percutaneous injury rate and the direct cost during the preintervention period (October 2004 through March 2005) and the intervention period (October 2005 through March 2006). RESULTS: We observed a 93% reduction in the relative risk of percutaneous injuries in areas where safety devices were used (14 vs 1 percutaneous injury). Specifically, rates decreased from 18.3 injuries (95% confidence interval [CI], 5.9-43.2 injuries) to 0 injuries per 100,000 patients in the emergency department (P=.002) and from 44.0 injuries (95% CI, 20.1-83.6 injuries) to 5.2 injuries (95% CI, 0.1-28.8 injuries) per 100,000 patient-days in hospital wards (P=.007). In the control wards of the hospital (ie, those where the intervention was not implemented), rates remained stable. The direct cost increase was 0.558 euros (US$0.753) per patient in the emergency department and 0.636 euros (US$0.858) per patient-day in the hospital wards. CONCLUSION: Proper use of engineered devices to prevent percutaneous injury is a highly effective measure to prevent these injuries among healthcare workers. However, education and training are the keys to achieving the greatest preventative effect.

Manufacture and Properties of Glucomannans and Glucomannooligosaccharides Derived from Konjac and Other Sources.

Glucomannans (GM) are polymers that can be found in natural resources, such as tubers, bulbs, roots, and both hard- and softwoods. In fact, mannan-based polysaccharides represent the largest hemicellulose fraction in softwoods. In addition to their structural functions and their role as energy reserve, they have been assessed for their healthy applications, including their role as new source of prebiotics. This paper summarizes the scientific literature regarding the manufacture and functional properties of GM and their hydrolysis products with a special focus on their prebiotic activity.

Assessment of the prebiotic effect of quinoa and amaranth in the human intestinal ecosystem.

Quinoa and amaranth belong to the group of the so called "superfoods" and have a nutritional composition that confers multiple benefits. In this work, we explored the possibility of these foods exhibiting a prebiotic effect. These pseudocereals were subjected to an in vitro digestion and used as carbon sources in batch cultures with faecal human inocula. The effects on the microbiota composition and their metabolic products were determined by assessment of variations in pH, short-chain fatty acid (SCFA) production and changes in the dynamic bacterial populations by fluorescence in situ hybridization (FISH). After 48 h of incubation, the total SCFAs were 106.5 mM for quinoa and 108.83 mM for amaranth, in line with the decrease in pH. Considerable differences (p < 0.05) were found in certain microbial groups, including Bifidobacterium spp., Lactobacillus-Enterococcus, Atopobium, Bacteroides-Prevotella, Clostridium coccoides-Eubacterium rectale, Faecalibacterium prausnitzii and Roseburia intestinalis. Our research suggests that these pseudocereals can have the prebiotic potential and that their intake may improve dysbiosis or maintain the gastrointestinal health through a balanced intestinal microbiota, although additional studies are necessary.

Kinetic modelling of mancozeb hydrolysis and photolysis to ethylenethiourea and other by-products in water.

The aim of this study was to propose kinetic models suitable for reproducing and predicting mancozeb (Mz) conversion to by-products as a function of the operational conditions. The main factors (pH, temperature and light) potentially affecting the mancozeb degradation in aqueous models were studied by a multifactorial screening design. In addition, the response surface methodology (RSM) was applied to evaluate the interactive effects of these factors on ethylenethiourea (ETU) formation. The response surface revealed that the best degradation conditions to minimize mancozeb conversion to ETU were low pH (2), low temperature (25 °C) and darkness. Under these conditions, the percentage of mancozeb remained in the solution at 72 h was approximately 10% of the initial concentration and the percentage of ETU conversion was 5.4%. However, according to the model, in surface waters under typical environmental conditions (pH 8, 25 °C and light) the percentage of mancozeb conversion to ETU would be about 17.5%. The proposed model provides a satisfactory interpretation of the experimental data obtained during the hydrolysis of mancozeb.

A biorefinery approach based on fractionation with a cheap industrial by-product for getting value from an invasive woody species.

Acacia dealbata wood (an invasive species) was subjected to fractionation with glycerol (a cheap industrial by-product), and the resulting solid phase was used as a substrate for enzymatic hydrolysis. Glycerol fractionation allowed an extensive delignification while preserving cellulose in solid phase. The solids from the fractionation stage showed high susceptibility to enzymatic hydrolysis. Solids obtained under selected fractionation conditions (glycerol content of media, 80 wt%; duration, 1h; liquid to solid ratio, 6 g/g; alkaline and neutral washing stages) were subjected to enzymatic saccharification to achieve glucose concentrations up to 85.40 g/L, with almost complete cellulose conversion into glucose. The results confirmed the potential of glycerol as a fractionation agent for biorefineries.

Pectic oligosacharides from lemon peel wastes: production, purification, and chemical characterization.

Lemon peel wastes were extracted with water to remove free sugars and other soluble compounds, and the insoluble solid was employed as a substrate for the manufacture of pectin-derived oligosaccharides by processing with hot, compressed water. When water-extracted lemon peel wastes were treated with water at 160 °C, the oligomer concentration reached the maximum value (31 g/L). Autohydrolysis liquors were subjected to two membrane filtration stages (diafiltration followed by concentration), yielding a refined product containing about 98 wt % of oligomers at a global yield of 14 kg/100 kg oven-dry lemon peel. The concentrate contained oligogalacturonides (with DP in the range of 2-18) and arabinooligosaccharides (with DP in the range of 2-8).

Valorisation of a leguminous species, Sesbania grandiflora, by means of hydrothermal fractionation.

For the purpose of hydrolysing hemicelluloses to oligomers and monomers, Sesbania grandiflora samples were subjected to isothermal autohydrolysis in the temperatures ranging from 145 degrees C to 190 degrees C, using a solid to liquid ratio of 8 and reaction times up to 7.5 h. Kinetic models based on sequential pseudo-homogeneous first order Kinetics with Arrhenius type temperature dependence were employed for describing the time course of the main hemicelluloses compounds and their degradation products. The hydrothermal treatment results show that Sesbania grandiflora can be employed as an alternative raw material for the production of XOS leading to high concentrations of XOS (14.1 g/L in the experiment carried out at 190 degrees C and 0.1 h) and xylan to XOS conversion (62.6% in the experiment carried out at 190 degrees C and 6 min). The model proposed provides a satisfactory interpretation of the experimental data obtained in the hydrothermal treatments of this study.

Direct enzymatic production of oligosaccharide mixtures from sugar beet pulp: experimental evaluation and mathematical modeling.

The potential of sugar beet pulp as raw material for neutral and acidic oligosaccharide production by direct enzymatic treatment was evaluated. The effect of the polygalacturonase to solid ratio (PGaseSR), cellulase activity to polygalacturonase activity ratio (CPGaseR), and reaction time (t) on several dependent variables (selected to quantify the mass of recovered liquors, the conversion of each polysaccharide into monosaccharides, and the conversion of each polysaccharide into oligomers) was studied. Mathematical models suitable for reproducing and predicting the experimental results were also developed. Operational conditions leading to a maximum oligomer production were calculated from models being PGaseSR = 10 U/g, CPGaseR = 0.725 filter paper units/U, and t = 12.82 h. Under these conditions, the models predicted that 906 kg of liquors containing 26.7 kg of oligosaccharides can be obtained from 100 kg of SBP, the distribution being as follows: 5.9 kg of glucooligosaccharides, 2.4 kg of galactooligosaccharides, 9.7 kg of arabinooligosaccharides, and 8.7 kg of oligogalacturonides. Therefore, this study demonstrated that pectic oligomers (for which prebiotic properties have been reported) can be obtained from SBP at high yield by direct enzymatic hydrolysis using mixtures of cellulases and pectinases.