Ultrafiltration to Increase the Consistency of Fruit Pulps: The Role of Permeate Flux

Ultrafiltration is a well-known operation, widely used in food processing, especially to concentrate selectively liquid compounds. However, so far, it has been mainly used to change concentration and/or clarify liquids with low viscosity. Ultrafiltration has seldomly been applied to viscous fluids. In this study, it was used to increase the consistency of fruit pulps, without changing their taste and organoleptic properties. This paper reports the findings achieved in experimental runs carried out on a pilot plant, equipped with four ultrafiltration tubular membranes (total surface area = 0.8 m2). Raw fruit pulps, namely, apple, apricot, and pear, were used to study the influence of the operative parameters on the permeate flux and organoleptic properties of the final products (retentate and permeate). The flow rate was in the range of 3.0–5.1 m3/h, at 50 °C. The influence of temperature on the permeate flux was checked, with one run with apple pulp at 20 °C. As expected, the findings show that high flow rate and temperature improve the permeate flux. Membranes show different performance in permeate flux for the tested pulps. This is probably due to their different chemical and physical composition, which could be responsible for different fouling of the membrane and, as a consequence, a different resistance to the permeate flow. The final products have the same taste as the raw ones, and each of them can be used as it is or as an ingredient. These results have a technological relevance, and, besides, the study shows a methodology for future applications of ultrafiltration

Performance of a Freeze Concentration Pilot Plant during the Start-Up Phase

In this paper are presented the findings obtained during the start-up of a freeze concentration pilot plant, that operated with suspension crystallisation and with simulated fruit juices. Solutions with different initial concentrations were tested, with and without acidification, to simulate fruit characteristics and behaviour. The experimental runs demonstrated that solution acidity has negligible effects on the process performance, whereas the results showed that the initial solution concentration influences the start-up duration. During this time, the solution concentration grows by about 10 °Brix, and the maximum quantity of ice content inside the crystalliser is always lower than 40% by weight. These findings can help to predict the performance of a freeze concentration plant and may facilitate achieving target concentrations in a more efficient mode. Taken together, the data suggest that the initial concentration of the processed juice influences start-up duration and the achievable final concentration

Valorization of Cocoa Husks: Pectin Recovery

industries like the pharmaceutical or the food ones. In this frame, the husks of roasted cocoa beans, that are a by-product of the cocoa processing industry, can constitute a source of pectin. The recovery process has been already defined at laboratory scale with boiling acid extraction (pH 2.5). This process is suitable to recover a quantity of pectin, expressed as anhydro-galacturonic acid (AGA), around 8 g AGA/100 g dry husks; this pectin is characterized by low degree of methylation (%DM around 31) and acetylation degree lower than 2%. In this paper the effects of some operative conditions on pectin quantity and quality were studied, in order to optimize the parameters that can make the process economically competitive: the in-excess quantities of solvents and operation time were reduced, without altering yield and pectin characteristics. In particular, the extract was concentrated by 13.3%, the ethanol for pectin precipitation was reduced (ratio extract to ethanol equal to 1:4), and it was also demonstrated that a single washing with 40% ethanol is sufficient to obtain a purified product

Bioremediation of Agricultural Soils Polluted with Pesticides: A Review

Pesticides are chemical compounds used to eliminate pests; among them, herbicides are compounds particularly toxic to weeds, and this property is exploited to protect the crops from unwanted plants. Pesticides are used to protect and maximize the yield and quality of crops. The excessive use of these chemicals and their persistence in the environment have generated serious problems, namely pollution of soil, water, and, to a lower extent, air, causing harmful effects to the ecosystem and along the food chain. About soil pollution, the residual concentration of pesticides is often over the limits allowed by the regulations. Where this occurs, the challenge is to reduce the amount of these chemicals and obtain agricultural soils suitable for growing ecofriendly crops. The microbial metabolism of indigenous microorganisms can be exploited for degradation since bioremediation is an ecofriendly, cost-effective, rather efficient method compared to the physical and chemical ones. Several biodegradation techniques are available, based on bacterial, fungal, or enzymatic degradation. The removal efficiencies of these processes depend on the type of pollutant and the chemical and physical conditions of the soil. The regulation on the use of pesticides is strictly connected to their environmental impacts. Nowadays, every country can adopt regulations to restrict the consumption of pesticides, prohibit the most harmful ones, and define the admissible concentrations in the soil. However, this variability implies that each country has a different perception of the toxicology of these compounds, inducing different market values of the grown crops. This review aims to give a picture of the bioremediation of soils polluted with commercial pesticides, considering the features that characterize the main and most used ones, namely their classification and their toxicity, together with some elements of legislation into force around the world

Efficacy of Ciprofloxacin and Amoxicillin Removal and the Effect on the Biochemical Composition of Chlorella vulgaris

Antibiotics are frequently detected in the aquatic environment due to their excessive usage and low-efficiency removal in wastewater treatment plants. This can provide the origin to the development of antibiotic-resistant genes in the microbial community, with considerable ecotoxicity to the environment. Among the antibiotics, the occurrence of ciprofloxacin (CIP) and amoxicillin (AMX) has been detected in various water matrices at different concentrations around the Earth. They are designated as emerging contaminants (ECs). Microalga Chlorella vulgaris (C. vulgaris) has been extensively employed in phycoremediation studies for its acclimatization property, non-target organisms for antibiotics, and the production of value-added bioproducts utilizing the nutrients from the wastewater. In this study, C. vulgaris medium was spiked with 5 mg/L of CIP and AMX, and investigated for its growth-stimulating effects, antibiotic removal capabilities, and its effects on the biochemical composition of algal cells compared to the control medium for 7 days. The results demonstrated that C. vulgaris adapted the antibiotic spiked medium and removed CIP (37 +/- 2%) and AMX (25 +/- 3%), respectively. The operating mechanisms were bioadsorption, followed by bioaccumulation, and biodegradation, with an increase in cell density up to 46 +/- 3% (CIP) and 36 +/- 4% (AMX), compared to the control medium. Further investigations revealed that, in the CIP stress-induced algal medium, an increase in major photosynthetic pigment chlorophyll-a (30%) and biochemical composition (lipids (50%), carbohydrates (32%), and proteins (65%)) was observed, respectively, compared to the control medium. In the AMX stress-induced algal medium, increases in chlorophyll-a (22%), lipids (46%), carbohydrates (45%), and proteins (49%) production were observed compared to the control medium. Comparing the two different stress conditions and considering that CIP is more toxic than AMX, this study provided insights on the photosynthetic activity and biochemical composition of C. vulgaris during the stress conditions and the response of algae towards the specific antibiotic stress. The current study confirmed the ability of C. vulgaris to adapt, bioadsorb, bioaccumulate, and biodegrade emerging contaminants. Moreover, the results showed that C. vulgaris is not only able to remove CIP and AMX from the medium but also can increase the production of valuable biomass usable in the production of various bioproducts

Remediation of Metal/Metalloid-Polluted Soils: A Short Review

The contamination of soil by heavy metals and metalloids is a worldwide problem due to the accumulation of these compounds in the environment, endangering human health, plants, and animals. Heavy metals and metalloids are normally present in nature, but the rise of industrialization has led to concentrations higher than the admissible ones. They are non-biodegradable and toxic, even at very low concentrations. Residues accumulate in living beings and become dangerous every time they are assimilated and stored faster than they are metabolized. Thus, the potentially harmful effects are due to persistence in the environment, bioaccumulation in the organisms, and toxicity. The severity of the effect depends on the type of heavy metal or metalloid. Indeed, some heavy metals (e.g., Mn, Fe, Co, Ni) at very low concentrations are essential for living organisms, while others (e.g., Cd, Pb, and Hg) are nonessential and are toxic even in trace amounts. It is important to monitor the concentration of heavy metals and metalloids in the environment and adopt methods to remove them. For this purpose, various techniques have been developed over the years: physical remediation (e.g., washing, thermal desorption, solidification), chemical remediation (e.g., adsorption, catalysis, precipitation/solubilization, electrokinetic methods), biological remediation (e.g., biodegradation, phytoremediation, bioventing), and combined remediation (e.g., electrokinetic-microbial remediation; washing–microbial degradation). Some of these are well known and used on a large scale, while others are still at the research level. The main evaluation factors for the choice are contaminated site geology, contamination characteristics, cost, feasibility, and sustainability of the applied process, as well as the technology readiness level. This review aims to give a picture of the main techniques of heavy metal removal, also giving elements to assess their potential hazardousness due to their concentrations

Selective Removal of Diesel Oil Hydrocarbons in Aerobic Bioremediation

In soil bioremediation, the main target is the removal of pollutants to the maximum extent. Careful monitoring of pollution concentration provides information about the process efficacy and removal efficiency. Moreover, a detailed analysis of residual pollution composition provides a detailed picture of single compound removal or presence, especially of interest when pollution is constituted by a mixture of chemical species. This paper shows the first results of a study on the speciation of diesel oil compound removal from soils by aerobic remediation. The experimental study was carried out in a microcosm using indigenous microorganisms and adopting the biostimulation strategy with a mineral salt medium for bacteria. The microcosm contained 200 g of dry soil and 14 g of diesel oil with a carbon to nitrogen ratio (C/N) equal to 180 and water content (u%) equal to 12% by mass. The residual pollution concentration in soil was monitored for 138 days to evaluate both the overall removal efficiency and that for the main groups of hydrocarbons. The results showed that the pollution composition changed during the test because of the different rate of metabolization for the single compounds: the overall removal efficiency was about 65%, and that of different hydrocarbon clusters was between 53% and 88%. The monitoring data also allowed the kinetic study of the degradation process, which was better modeled by a second-order kinetic model than by a first-order one. These findings were confirmed by analyzing other microcosms with different operative conditions (C/N = 120, 180 and u% = 8%, 12%, 15% by mass). The proposed methodology may be useful for the evaluation of compliance to concentration limits imposed by law

Remediation of Lead and Nickel Contaminated Soil Using Nanoscale Zero-Valent Iron (nZVI) Particles Synthesized Using Green Leaves: First Results

4siNanoscale zero-valent iron (nZVI) particles have proved to be effective in the remediation of chlorinated compounds and heavy metals from contaminated soil. The present study aimed to analyze the performance of nanoparticles synthesized from low-cost biomass (green leaves) as chemical precursors, namely Azadirachta indica (neem) and Mentha longifolia (mint) leaves. These leaves were chosen because huge amounts of them are present in the region of Vellore. These nanoparticles were used to remove lead and nickel from contaminated soil. Characterization of nZVI particles was conducted using the Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Brunauer–Emmett–Teller isotherm (BET) techniques. Remediation was performed on two different soil samples, polluted with lead or nickel at an initial metal concentration around 250 mg/kg of soil. The results revealed that after 30 days, the lead removal efficiency with 0.1 g of nZVI particles/kg of soil was 26.9% by particles synthesized using neem leaves and 62.3% by particles synthesized using mint leaves. Similarly, nickel removal efficiency with 0.1 g of particles/kg of soil was 33.2% and 50.6%, respectively, by particles using neem and mint leaves. When the nanoparticle concentration was doubled, Pb and Ni removal improved, with similar trends obtained at a lower dosage (0.1 g of particles/kg of soil). These first results evidenced that: (1) the nZVI particles synthesized using green leaves had the potential to remove Pb and Ni from contaminated soil; (2) the neem-derived particles gave better Pb removal efficiency than Ni one; (3) the mint-derived particles showed better Ni removal efficiency than Pb one; (4) the highest removal efficiency for both metals was achieved with the mint-derived particles; (5) double higher dosage did not greatly improve the results.openopenFrancy, Nimita; Shanthakumar, Subramanian; Chiampo, Fulvia; Sekhar, Yendaluru RajaFrancy, Nimita; Shanthakumar, Subramanian; Chiampo, Fulvia; Sekhar, Yendaluru Raj

Integrated use of chemical and geophysical monitoring to study the diesel oil biodegradation in microcosms with different operative conditions

This study aimed to monitor the aerobic bioremediation of diesel oil-contaminated soil by measuring: a) the CO2 production; 2) the fluorescein production; 3) the residual diesel oil concentration.Moreover, the complex dielectric permittivity was monitored through an open-ended coaxial cable. Several microcosms were prepared, changing the water content (u%= 8–15% by weight), the carbon to nitrogen ratio (C/N = 20–450), and the soil amount (200 and 800 g of dry soil). The cumulative CO2 and fluorescein production showed similar trends, but different values since these two parameters reflect different features of the biological process occurring within each microcosm. The diesel oil removal efficiency depended on the microcosm characteristics. After 84 days, in the microcosms with 200 g of dry soil, the highest removal efficiency was achieved with a water content of 8% by weight and C/N = 120, while in themicrocosms with 800 g of dry soil the best result was achieved with the water content equal to 12%by weight and C/N = 100. In the tested soil, the bioremediation process is efficient if the water content is in the range 8–12% by weight, and C/N is in the range 100–180; under these operative conditions, the diesel oil removal efficiency was about 65–70¯ter 84 days. The dielectric permittivity wasmonitored in microcosms with 200 g of dry soil. The open-ended coaxial cable detected significant variations of both the real and the imaginary component of the dielectric permittivity during the bioremediation process, due to the physical and chemical changes that occurred within the microcosms