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Extraction and encapsulation of Bio-components from Tomato Waste for Food and Biomedical Applications
No full textTomato waste (TW), the solid residue left after the industrial processing of tomatoes, is considered as one of the most promising candidates to recovery the lycopene. It consists mainly of tomato peels and seeds making up about 3 % to 5 % of the total weight of processed tomatoes which depends on their specific production process. The World Processing Tomato Council (WPTC) estimates that the annual production of tomatoes in Italy is around 5.5 million tons and at a global more than 40 million tons, resulting in the overall production of large quantities of waste after industrial processing of the tomato. Discarding TW directly not only results in a huge loss of valuable materials, but also poses serious management problems from both the economic and environmental point of view. Considering its nutritional properties, however, it is a promising source of biocompounds according to previous studies. Tomato waste consists mainly of pericarp and seeds, of which fiber is the major compound accounting for 25.4 - 50.0 % of the dry matter. The other components are 15.4 - 23.7 % of total protein, 5.4 - 20.5 % of total fat, and 4.4 - 6.8 % of mineral. More importantly, this by-product contains valuable antioxidants which can be extracted by means of proper extraction methods. Effective utilization of food by-products/wastes as a secondary source for new products has been an emerging research topic in recent years. Tomato processing wastes have been the subject of significant research, especially the recovery of lycopene through efficient extraction methods. Unfortunately, lycopene is nonpolar and readily degradable, so lycopene extraction, processing, and analysis must be performed under controlled conditions to minimize oxidative degradation and isomer formation. Conventional methods of lycopene extraction have non-negligible drawbacks such as time-consuming, toxic chemicals and low efficiency. In recent years, a variety of high efficient extraction techniques have emerged, including microwave, ultrasonic, supercritical fluid and pressurized liquid extraction. These non-conventional techniques exhibit several advantages for the extraction of bioactive molecules, such as a shorter processing time, reduction in the use of organic solvents as well as mild operating parameters to avoid thermal degradation. Therefore, they are environmentally friendly and usually result in higher yields and high-quality final extracts.
In this thesis, a preliminary characterization of TW was carried out and different extraction techniques (solid-liquid extraction, ultrasound-assisted extraction, microwave-assisted extraction under pressure and solid-liquid multivariable extractor) were investigated with ethanol and water or their mixed solutions as green solvents. One of the objectives of this research project was to recover lycopene from TW using ethanol solutions as green solvents and to improve the extraction rate by modulating process variables. In this study, response surface modeling and kinetic studies were used as tools for processing optimization and the extracts were evaluated as total lycopene yield and antiradical power.
Since it is rapidly susceptible to degradation and isomerization upon exposure to heat, light or oxygen, lycopene can lose its activity and medical effects without proper protection. Accordingly, the second research objective of this thesis was to analyze and evaluate the protective effect on lycopene by using different methods (oil-in-water nanoemulsion, spray drying method and supercritical CO2). Among xxx, the oil-in-water nanoemulsion method was carried out with isopropyl myristate as oil phase and Pluronic F-127 as emulsifier. The stability of the nanoemulsion particles and the lycopene content in nanoemulsion were initially characterized at different temperatures. Further, TW extracts as well as oil-in-water nanoemulsions were directly microencapsulated by spray drying and supercritical CO2 using inulin and maltodextrin as wall materials. The encapsulation process was optimized by modulating different parameters (e.g., coating agent composition, inlet temperature, feed flow rate, feed flow rate of CO2 and feed flow rate of N2) and was analyzed using the Response Surface Methodology.
The results about the characterization of TW showed on initial moisture content, approximately 84.3 ± 0.83 %. After the drying process, a final moisture of approximately 6 % of residual moisture. Particularly, after the drying process, the TW exhibited a water activity of 0.101 ± 0.042, resulting as suitable for long-term storage in water-proof containers and in the dark for extraction experiments. After crushing, the average diameter of the particles is smaller (732 ± 67 μm), making it possible to directly use TW for extraction. The biomass showed an ash content of 4.1 ± 0.8 %. SLE using hexane as solvent was carried out for the quantification of lycopene as reference. The total lycopene content was 1438.24 ± 44.3 μg/g (dry solid), measured via HPLC. SLE using sunflower seed oil as solvent was carried out for a general traditional extraction. The results showed that the optimal conditions were T = 45 °C, L/S = 20/3 mL/g, stirring speed = 900 rpm, t = 45 min. The total lycopene content was 1237.32 ± 4.80 μg lycopene equivalent/g (dry solid) measured by UV-vis spectrophotometer. UAE extraction using ethanol as solvent as advanced extraction method was carried out. Response Surface Methodology was used to investigate the effect of the ultrasound-assisted extraction parameters on the extract bioactive content. The optimal conditions found by the desirability method (T = 65 °C, t = 20 min, L/S = 72 mL/g, A = 65 %, on/off = 33/30 s/s, V = 90 mL) were experimentally verified and the total lycopene content was 1536 ± 53 μg/g (dry solid), measured via HPLC. It was also found that the frequency of ultrasonic vibration studied (40kHz, 80kHz, 120kHz) did not significantly improve the lycopene extraction yield. SoLVE extraction using ethanol as solvent as the focus of this chapter was carried out. The optimal conditions also found by the desirability method (CCD) (T = 65 °C, t = 41 min, L/S = 27 mL/g, A = 39 %, on/off = 32/30 s/s) were experimentally verified. Under optimal conditions, the trans-lycopene yield was of 546.7 μg/g and the total lycopene yield was 1193.0 μg lycopene equivalents/g. In addition, the extraction kinetic model was found to be consistent with the Peleg’s model through the study of the extraction kinetics during the extraction process. Finally, microwave-assisted subcritical extraction method was used to study and compare the extraction of lycopene with the extraction conditions of UAE and SoLVE. The optimal conditions were T = 100 °C, L/S = 72 mL/g, V = 30 mL, t = 15 min. The maximum total lycopene content was 962.97 ± 42.87 μg/g (dry solid), the trans-lycopene yield was of 662.84 ± 24.55 μg/g (dry solid), measured via HPLC. Due to the instability of lycopene, it is easily degraded under the influence of external factors (temperature, light, oxygen, pH). Therefore, further research on the protection of lycopene is necessary. This study used different technologies to encapsulate and protect lycopene through solid and liquid formulations. In the part of encapsulation, nanoemulsions were found stable for up to three months at the optimal storage temperature (4 °C) as no significant agglomeration was observed. The addition of extracted solution was found to significantly reduce the droplet size and increase the stability of nanoemulsions. The spray drying technology was found efficient for transferring the nanoemulsion to solid powder. The operating conditions at which spray drying reached the highest recovery were the input temperature 170 °C, the gas flow rate 35 m3/h, the flow rate of the nanoemulsion 6 mL/min and the coating agent (maltodextrin) at 40 % w/w. Under the optimal conditions, the recovery of the product reached 80.3 %. Furthermore, as a comparison, a feasibility evaluation of the encapsulation of the obtained extract by spray drying was carried out, investigating the possibility to add inulin in the composition of the wall material. The best results were obtained at the lowest percentage of inulin (21.7 % inulin and 78.3 % of maltodextrins). Finally, a SAA laboratory apparatus was adopted to dry the nanoemulsions, and different coating agents, CO2 flow rate, temperature, feed flow rate, and production recovery were evaluated
Double emulsion with improved stability for Lactobacillus acidophilus encapsulation in a liquid formulation
No full textNowadays, probiotics cover a fundamental role in the sector of functional food. Despite the several benefits on human health related to the probiotic consumption, their delivery is still a challenge due to their high sensitivity to environmental stresses. Encapsulation can improve their vitality and stability, allowing survival during storage and consumption. Double emulsions are selected as potential encapsulating systems due to their unique multi-compartmentalizing structure. The objective of this work was to stabilize Lactobacillus acidophilus in a double emulsion to have directly a liquid formulation. The double emulsion was produced using a rotor-stator emulsifier and the selected emulsion compounds have been chosen to be suitable for food applications. A feasibility study on operating conditions was carried out to identify the best production conditions. The loaded emulsions were characterized in terms of morphology, microorganism vitality, encapsulation efficiency, stability over time, and survival to in vitro digestion. As main results, the operating conditions allowed the desired size of about 5 μm, they did not affect the microbial vitality allowing an encapsulation efficiency of 95–99%. Moreover, the physical and microbial stability were ensured over a period of 45 days of storage at 4 °C. In particular, the sunflower oil as carrier agent guaranteed a survival rate of 85% after one month. Finally, the encapsulated strain was able to survive during digestion in comparison with the non-encapsulated one, ensuring a microbial survival of about 62%. Double emulsions emerge as a promising encapsulation system for obtaining a liquid formulation with enhanced long-term stability for food applications
Oil-in-water nanoemulsions loaded with lycopene extracts encapsulated by spray drying: Formulation, characterization and optimization
No full textLycopene is very susceptible to degradation once released from the protective chromoplast environment. In this study, oil-in-water (O/W) nanoemulsions coupled with spray drying technology were applied for the encapsulation and stabilization of lycopene extracted from tomato waste. Tomato extract was obtained by ultrasound-assisted extraction. Nanoemulsions were prepared by a high-speed rotor stator using isopropyl myristate as the oil phase and Pluronic F-127 as the emulsifier for the aqueous external phase. The effect of emulsification process parameters was investigated. Spray drying of the produced emulsions was attempted to obtain a stabilized dry powder after the addition of a coating agent. The effect of different coating agents (maltodextrin, inulin, gum arabic, pectin, whey and polyvinylpyrrolidone), drying temperature (120–170 °C), and feed flow rate (3–9 ml·min−1) on the obtained particles was evaluated. Results revealed that the emulsion formulation of 20/80 (O/W) with 1.5% (mass fraction) of Pluronic F-127 as stabilizer in the aqueous phase resulted in a stable nanoemulsion with droplet sizes in the range of 259–276 nm with a unimodal and sharp size distribution. The extract in the nanoemulsion was well protected at room temperature with a degradation rate of lycopene of about 50% during a month of storage time. The most stable emulsions were then processed by spray drying to obtain a dry powder. Spray drying was particularly successful when using maltodextrin as a coating agent, obtaining dried spherical particles with mean diameters of 4.87±0.17 μm with a smooth surface. The possibility of dissolving the spray dried powder in order to repristinate. The original emulsion was also successfully verified
Valorisation of tomato peel waste for lycopene encapsulation: Optimization and comparison of two green techniques
No full textLycopene, a lipid-soluble carotenoid with potent antioxidant properties, is typically found in tomato peels, which are often discarded as by-products in the food industry. This study focused on extracting lycopene using solvent extraction and encapsulating it in polycaprolactone (PCL), a biodegradable polymer, using two different methods: solvent evaporation and supercritical emulsion extraction (SEE). Both methods were used to produce microparticles for nutraceutical applications. An optimization study based on Box-Behnken design and response surface modelling was conducted to assess the effects of emulsification stirring speed, emulsification time, and polymer amount on encapsulation efficiency and particle size. Particle sizes, measured by laser diffraction, ranged between 1.77 ± 0.10 and 2.82 ± 0.17 μm for solvent evaporation, and between 1.12 ± 0.03 and 2.72 ± 0.15 μm for SEE. Encapsulation efficiencies, measured by UV–vis spectroscopy, ranged between 28.45 ± 0.28 % and 89.94 ± 1.70 % for solvent evaporation, and between 66.52 ± 0.64 % and 89.45 ± 1.31 % for SEE. Results show that SEE yields more consistent encapsulation efficiencies compared to solvent evaporation. Additionally, the design of experiments (DoE) approach helped identify optimal conditions that minimize waste and maximize productivity. This work offers a sustainable method for converting agro-industrial waste into valuable nutraceutical products
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
High-Pressure Technologies for the Recovery of Bioactive Molecules from Agro-Industrial Waste
No full textLarge amounts of food waste are produced each year. These residues require appropriate management to reduce their environmental impact and, at the same time, economic loss. However, this waste is still rich in compounds (e.g., colorants, antioxidants, polyphenols, fatty acids, vitamins, and proteins) that can find potential applications in food, pharmaceutical, and cosmetic industries. Conventional extraction techniques suffer some drawbacks when applied to the exploitation of food residues, including large amounts of polluting solvents, increased time of extraction, possible degradation of the active molecules during extraction, low yields, and reduced extraction selectivity. For these reasons, advanced extraction techniques have emerged in order to obtain efficient residue exploitation using more sustainable processes. In particular, performing extraction under high-pressure conditions, such as supercritical fluids and pressurized liquid extraction, offers several advantages for the extraction of bioactive molecules. These include the reduced use of toxic solvents, reduced extraction time, high selectivity, and the possibility of being applied in combination in a cascade of progressive extractions. In this review, an overview of high-pressure extraction techniques related to the recovery of high added value compounds from waste generated in food industries is presented and a critical discussion of the advantages and disadvantages of each process is reported. Furthermore, the possibility of combined multi-stage extractions, as well as economic and environmental aspects, are discussed in order to provide a complete overview of the topic
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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