Effects of Electron Beam Radiation on the Phenolic Composition and Bioactive Properties of Olive Pomace Extracts.

Olive pomace is an agro-industrial waste product generated from the olive oil industry and constituted by bioactive compounds with potential applications in several industrial sectors. The purpose of this work was to evaluate the effects of electron beam (e-beam) radiation on olive pomace, specifically on phenolic compounds (by HPLC-DAD-ESI/MS) and the bioactive properties (antioxidant, antiproliferative, and antimicrobial activities) of crude olive pomace (COP) and extracted olive pomace (EOP) extracts. The amount of total flavonoid content and the reducing power of COP extracts were higher than those obtained for EOP extracts. The results suggested that e-beam radiation at 6 kGy increased both total phenolic and total flavonoid contents as well as the reducing power of COP extracts, due to the higher extractability (>2.5-fold) of phenolic compounds from these samples, while decreasing the scavenging activity of extracts. The extracts of both olive pomaces showed antibacterial potential, and COP extracts at 400 µg/mL also presented antiproliferative activity against A549, Caco-2, 293T, and RAW264.7 cell lines, with both properties preserved with the e-beam treatment. All in all, e-beam radiation at 6 kGy appears to be a promising technology to valorize the pollutant wastes of the olive oil industry through enhancing phenolic extractability and bioactive properties, and, furthermore, to contribute to the environmental and economical sustainability of the olive oil industry.

Microbiota Assessment of Fresh-Cut Apples Packaged in Two Different Films.

The aim of this work was to assess the natural microbiota of packed fresh-cut apples during refrigerated storage. Two different films were tested for the package, a biodegradable (PLA) film and a conventional and commercial one (OPP). Two antioxidant additives were applied, a natural olive pomace extract and the commercial ascorbic acid used by the industries. The results revealed lower bacteria counts in samples with olive pomace extract and PLA films than in those with ascorbic acid and OPP films after 5 and 12 days of storage. These findings suggest that the use of such natural extracts as additives in fruits could delay the growth of mesophilic bacteria. The characterization and identification of the bacterial isolates from fresh-cut apple samples showed that the most prevalent species were Citrobacter freundii, Staphylococcus warneri, Pseudomonas oryzihabitans, Alcalinogenes faecalis, Corynebacterium jeikeium, Micrococcus spp., Pantoea aglomerans and Bacillus spp. Furthermore, an increase in the microbial diversity during the storage time at refrigerated temperatures was observed, except for the sample treated with olive pomace extract and packaged in OPP film. The highest microbial diversity was found for samples with ascorbic acid as an additive. This could indicate a negative effect of ascorbic acid on the microbial inhibition of apple slices. The natural olive pomace extract demonstrated potential as an antimicrobial additive for fresh-cut apples.

Effect of Olive Pomace Extract Application and Packaging Material on the Preservation of Fresh-Cut Royal Gala Apples.

The efficiency of natural olive pomace extracts for enhancing the quality of fresh-cut apples was compared with commercial ascorbic acid and two different packaging films (biodegradable polylactic acid (PLA) and oriented polypropylene (OPP)) were tested. The composition of atmosphere inside the packages, the physicochemical parameters (firmness, weight loss and color), the microbial load, total phenolic content and antioxidant activity of fresh-cut apples were evaluated throughout 12 days of storage at 4 °C. After 12 days of refrigerated storage, a significant decrease in O2 was promoted in PLA films, and the weight loss of the whole packaging was higher in PLA films (5.4%) than in OPP films (0.2%). Natural olive pomace extracts reduced the load of mesophilic bacteria (3.4 ± 0.1 log CFU/g and 2.4 ± 0.1 log CFU/g for OPP and PLA films, respectively) and filamentous fungi (3.3 ± 0.1 log CFU/g and 2.44 ± 0.05 log CFU/g for OPP and PLA films, respectively) growth in fresh-cut apples after five days of storage at 4 °C, and no detection of coliforms was verified throughout the 12 days of storage. In general, the olive pomace extract preserved or improved the total phenolic index and antioxidant potential of the fruit, without significant changes in their firmness. Moreover, this extract seemed to be more effective when combined with the biodegradable PLA film packaging. This work can contribute to the availability of effective natural food additives, the sustainability of the olive oil industries and the reduction of environmental impact. It can also be useful in meeting the food industries requirements to develop new functional food products.

Ultrasound-assisted extraction of hydroxytyrosol and tyrosol from olive pomace treated by gamma radiation: process optimization and bioactivity assessment.

Ultrasound-assisted extraction (UAE) was used to recover hydroxytyrosol and tyrosol from olive pomace, a residue generated by the olive oil industry. The extraction process was optimized using response surface methodology (RSM), with processing time, ethanol concentration and ultrasonic power as the combined independent variables. The highest amounts of hydroxytyrosol (36 ± 2 mg g-1 of extract) and tyrosol (14 ± 1 mg g-1 of extract) were obtained after 28 min of sonication at 490 W using 7.3% ethanol as the solvent. Under these global conditions, an extraction yield of 30 ± 2% was achieved. The bioactivity of the extract obtained under optimized UAE was evaluated and compared with that of an extract obtained under optimal heat-assisted extraction (HAE) conditions in a previous work of the authors. Compared to HAE, UAE reduced the extraction time and the solvent consumption, and also led to higher extraction yields (HAE yield was 13.7%). Despite this, HAE extract presented higher antioxidant, antidiabetic, anti-inflammatory and antibacterial activities and no antifungal potential against C. albicans. Furthermore, HAE extract also showed higher cytotoxic effects against the breast adenocarcinoma (MCF-7) cell line. These findings provide useful information for the food and pharmaceutical industries in developing new bioactive ingredients, which may represent a sustainable alternative to synthetic preservatives and/or additives.

Inactivation mechanisms of human adenovirus by e-beam irradiation in water environments.

This study aims to study the kinetics and mechanisms of human adenovirus inactivation by electron beam. Human adenovirus type 5 (HAdV-5) was inoculated in two types of aqueous substrates (phosphate-buffered saline - PBS, domestic wastewater - WW) treated by electron beam at a dose range between 3 and 21 kGy. Samples were evaluated for virus infectivity, PCR amplification of fragments of HAdV-5 genome and abundance and antigenicity of the virion structural proteins. The maximum reduction in viral titre, in plaque-forming units (PFU) per millilitre, was about 7 and 5 log PFU/mL for e-beam irradiation at 20 kGy in PBS and 19 kGy in wastewater, respectively. Among the virion structural proteins detected, the hexon protein showed the higher radioresistance. Long (10.1 kbp) genomic DNA fragments were differently PCR amplified, denoting a substrate effect on HAdV-5 genome degradation by e-beam. The differences observed between the two substrates can be explained by the protective effect that the organic matter present in the substrate may have on viral irradiation. According to the obtained results, the decrease in viral viability/infectivity may be due to DNA damage and to protein alterations. In summary, electron beam irradiation at a dose of 13 kGy is capable of reducing HAdV-5 viral titres by more than 99.99% (4 log PFU/mL) in both substrates assayed, indicating that this type of technology is effective for viral wastewater disinfection and may be used as a tertiary treatment in water treatment plants. KEY POINTS: • The substrate in which the virus is suspended has an impact on its sensitivity to e-beam treatment. • E-beam irradiation at 13 kGy is capable of reducing by 4 Log PFU/mL the HAdV-5 viral titre. • The decrease in viral viability/infectivity may be due to DNA damage and to protein alterations.

Applications of bioactive compounds extracted from olive industry wastes: A review.

The wastes generated during the olive oil extraction process, even if presenting a negative impact for the environment, contain several bioactive compounds that have considerable health benefits. After suitable extraction and purification, these compounds can be used as food antioxidants or as active ingredients in nutraceutical and cosmetic products due to their interesting technological and pharmaceutical properties. The aim of this review, after presenting general applications of the different types of wastes generated from this industry, is to focus on the olive pomace produced by the two-phase system and to explore the challenging applications of the main individual compounds present in this waste. Hydroxytyrosol, tyrosol, oleuropein, oleuropein aglycone, and verbascoside are the most abundant bioactive compounds present in olive pomace. Besides their antioxidant activity, these compounds also demonstrated other biological properties such as antimicrobial, anticancer, or anti-inflammatory, thus being used in formulations to produce pharmaceutical and cosmetic products or in the fortification of food. Nevertheless, it is mandatory to involve both industries and researchers to create strategies to valorize these byproducts while maintaining environmental sustainability.

Ionizing Radiation Technologies to Increase the Extraction of Bioactive Compounds from Agro-Industrial Residues: A Review.

Due to the growing demand in society for healthier foods, scientific communities are searching and developing new ingredients. In this context, agro-industrial residues, which can have a negative impact on the environment, represent a natural source for bioactive compounds and their recovery can contribute to economic and environmental sustainability. Ionizing radiation is a clean and eco-friendly technology that can be used to improve the extraction of bioactive compounds. The aim of this review, after presenting general aspects about bioactive compounds in agro-industrial residues and radiation technologies, is to focus on the effects of ionizing radiation on the extraction of bioactive compounds from these residues and related bioactive properties. Irradiated residues were demonstrated to have enhanced bioactive characteristics that turn the prepared extracts suitable for applications in food industry, resulting in high-added-value products as well as reducing adverse impacts on the environment.

The use of gamma radiation for extractability improvement of bioactive compounds in olive oil wastes.

Olive pomace is an environmentally detrimental waste from olive oil industry, containing large amounts of bioactive compounds that might be used by the food industry. In this work, the effects of gamma radiation on phenolic compounds and bioactive properties (antioxidant, antimicrobial activities and hepatotoxicity) of Crude Olive Pomace (COP) and Extracted Olive Pomace (EOP) extracts were evaluated. Hydroxytyrosol was the main phenolic compound identified in both olive pomace extracts (24-25 mg/g). The gamma radiation treatment of olive pomace improved at least 2-fold the extractability of phenolic compounds. Moreover, results suggested that gamma radiation at 5 kGy increased the antioxidant activity in EOP, while keeping the ability to protect erythrocytes against oxidation-induced haemolysis. Gamma radiation at 5 kGy could be a suitable technology for olive oil pomaces waste valorization, contributing to enhance extraction of phenolic compounds and bioactive properties, especially when applied on extracted material.

Virucidal activity of gamma radiation on strawberries and raspberries.

The environmental stability of enteric viruses and resistance to conventional treatments and common disinfectants, leads to their persistence in waters and food, causing serious implications on public health. Among non-thermal treatment methods, ionizing radiation is recognized as a useful and effective mean of disinfection. The objective of this study was to estimate the inactivation of enteric virus by gamma radiation in raw berry fruits, in order to evaluate the potential of this technology to be applied as a disinfection treatment. Fresh strawberries and raspberries were inoculated either individually with murine norovirus type 1 (MuNoV; as a human norovirus surrogate) and human adenovirus type 5 (HAdV) or with a viral pool of both viruses, and irradiated in a Co-60 equipment at doses of 1 kGy up to 11 kGy. The infectivity of viral particles of MuNoV and HAdV was assessed by plaque assay using Raw 264.7 and A549 cells, respectively. A 2 log PFU/g reduction on MuNoV and HAdV titers was obtained after treatment with a dose of 4 kGy for both fruits. However, non-linear inactivation survival curves were obtained for MuNoV and HAdV in fresh fruits, leading to the detection of infective viral particles at a dose of 11 kGy. The irradiation process indicated virucidal potential, although the estimated gamma radiation dose to attain food safety (> 7 kGy) would compromise the preservation of food quality. Nevertheless, the irradiation technology could be an effective virus mitigation tool to treat polluted waters, which are a major vehicle of contamination for fresh produce.

Recovery of phenolic compounds from multi-component solution by a synthesized activated carbon using resorcinol and formaldehyde.

The adsorption of four phenolic compounds (gallic acid, protocatechuic acid, vanillic acid and syringic acid) is investigated using a synthesized mesoporous carbon on both single and multi-component synthetic solutions. Some correlation of the adsorption capacity of the carbon and the nature of adsorbate could be made, except for gallic acid whose concentration decrease seems to be not exclusively due to adsorption but also to polymerization reaction. In the multi-component mixture, negative effects in the adsorption capacity are observed probably due to competition for the active centers of the adsorbent surface. In desorption studies, ethanol presents better performance than water and acetonitrile. Vanillic acid is the compound with the higher adsorption and interestingly it is then possible to desorb a relatively high amount of it from the adsorbent, which may represent a possibility for a selective recovery of vanillic acid. These results present a potential way to treat the wastewater from the cork industry.

Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation.

In this work, we study degradation of clofibric acid (CFA) in aqueous solution using either ionizing radiation from a60Co source or a non-thermal plasma produced by discharges in the air above the solution. The results obtained with the two technologies are compared in terms of effectiveness of CFA degradation and its by-products. In both cases the CFA degradation follows a quasi-exponential decay in time well modelled by a kinetic scheme which considers the competition between CFA and all reaction intermediates for the reactive species generated in solution as well as the amount of the end product formed. A new degradation law is deduced to explain the results. Although the end-product CO2 was detected and the CFA conversion found to be very high under the studied conditions, HPLC analysis reveals several degradation intermediates still bearing the aromatic ring with the chlorine substituent. The extent of mineralization is rather limited. The energy yield is found to be higher in the gamma radiation experiments.

Effects of gamma radiation on cork wastewater: Antioxidant activity and toxicity.

A comprehensive assessment of the toxicity and antioxidant activity of cork boiling wastewater and the effects of gamma radiation on these parameters was performed. Antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of ß-carotene bleaching. The results have shown that gamma radiation can induce an increase on the antioxidant activity of cork boiling wastewater. Toxicity tests were performed to access the potential added value of the irradiated wastewaters and/or minimization of the impact for discharge in the environment. Two different methods for toxicity evaluation were followed, bacterial growth inhibition test and cytotoxicity assay, in order to predict the behavior of different cells (prokaryotic and eukaryotic) in the presence of cork wastewater. Non-treated cork boiling wastewater seemed to be non-toxic for prokaryotic cells (Pseudomonas fluorescens and Bacillus subtilis) but toxic for eukaryotic cells (A549 human cells and RAW264.7 mouse cells). The gamma radiation treatment at doses of 100 kGy appeared to increase the toxicity of cork compounds for all tested cells, which could be related to a toxic effect of radiolytic products of cork compounds in the wastewaters.

Tracking Human Adenovirus Inactivation by Gamma Radiation under Different Environmental Conditions.

UNLABELLED: Adenovirus is the most prevalent enteric virus in waters worldwide due to its environmental stability, which leads to public health concerns. Mitigation strategies are therefore required. The aim of this study was to assess the inactivation of human adenovirus type 5 (HAdV-5) by gamma radiation in aqueous environments. Various substrates with different organic loads, including domestic wastewater, were inoculated with HAdV-5 either individually or in a viral pool (with murine norovirus type 1 [MNV-1]) and were irradiated in a Cobalt-60 irradiator at several gamma radiation doses (0.9 to 10.8 kGy). The infectivity of viral particles, before and after irradiation, was tested by plaque assay using A549 cells. D10 values (dose required to inactivate 90% of a population or the dose of irradiation needed to produce a 1 log10 reduction in the population) were estimated for each substrate based on virus infectivity inactivation exponential kinetics. The capability of two detection methods, nested PCR and enzyme-linked immunosorbent assay (ELISA), to track inactivated viral particles was also assessed. After irradiation at 3.5 kGy, a reduction of the HAdV-5 titer of 4 log PFU/ml on substrates with lower organic loads was obtained, but in highly organic matrixes, the virus titer reduction was only 1 log PFU/ml. The D10 values of HAdV-5 in high organic substrates were significantly higher than in water suspensions. The obtained results point out some discrepancies between nested PCR, ELISA, and plaque assay on the assessments of HAdV-5 inactivation. These results suggest that the inactivation of HAdV-5 by gamma radiation, in aqueous environments, is significantly affected by substrate composition. This study highlights the virucidal potential of gamma radiation that may be used as a disinfection treatment for sustainable water supplies. IMPORTANCE: Human adenovirus (HAdV) is the most prevalent of the enteric viruses in environmental waters worldwide. The purposes of this study are to provide new insights on the inactivation of enteric virus by gamma irradiation and to introduce new concepts and reinforce the benefits and utility of radiation technologies as disinfection processes. This may be an effective tool to guarantee the reduction of viral pathogens and to contribute to public health and sustainable water supplies.

Evaluating structural and microstructural changes of PDMS-SiO2 hybrid materials after sterilization by gamma irradiation.

PDMS-SiO2 hybrid materials obtained by sol-gel process have been extensively studied over the past years due to its promising biomedical applications namely as bone substitutes, catheters, and drug delivery devices. Regardless of the intended biomedical application, all these materials should go through a sterilization process before interfacing with a living structure. However, it is unclear whether they undergo structural and microstructural changes when subjected to sterilization by gamma irradiation. This paper addresses this issue by showing that a sol-gel processed biomaterial based on the PDMS-CaO-SiO2 hybrid system suffers only small structural changes when submitted to a radiation dose of 25kGy, the dose usually recommended to achieve a Sterility Assurance Level of 10(-6) when the natural contamination level and microorganism types cannot be calculated. The characterization was assessed by FT-IR, (29)Si-{(1)H} CP-MAS, thermal analysis (DTG), and SEM.