Valorization Of By-products Research Articles

Design Optimization of a Tray Bioreactor for Solid-State Fermentation: Study of Process Parameters through Protein Modification of By-Products

This study investigated the design of a tray bioreactor for solid-state fermentation, applying Rhizopus oryzae to oilseed meals as the substrate. Two process variables were continuously monitored in the bioreactor to ensure precise control of the environmental conditions: temperature and relative humidity (RH). The comprehensive analysis covered the effects of different fermentation conditions on the protein content, technological properties, and molecular distribution of the samples. The study revealed that the configuration factors suffered a stratification within the three trays of the bioreactor. Notably, the upper tray registered the largest dispersion, with a range of 1.5 °C. When analyzing the differences between sensors within each tray, the largest difference was found in the lower tray (10.9%). Furthermore, higher EAI (Emulsifying Activity Index) values were observed in the upper tray (T3) for rapeseed. As for ESI (Emulsion Stability Index) values, no differences were observed between the trays or fermentation periods. Using the changes induced by Rhizopus oryzae fungal enzymes, the study quantitatively examined the changes in the by-product valorization. While the bioreactor factors did not affect the protein quantity itself, they had significant impacts on specific changes within the molecular weight protein fraction. The findings of this study offer significant insights into the complex dynamics of solid-state fermentation processes. The outcomes of this study not only advance understanding of solid-state fermentation but also offer practical guidance for the design and operation of fermenters in industrial applications.

Recent Trends in Valorization of Food Industry Waste and By-Products: Encapsulation and In Vitro Release of Bioactive Compounds.

Food by-products and waste are a boundless source of bioactives, nutraceuticals, and naturally occurring substances that are good for human health. In fact, a lot of by-products and wastes are generated by several food businesses. Therefore, waste management and by-product utilization are the most important aspects of the food sector. According to various studies, many bioactive compounds such as phenolics, carotenoids, and proteins can be recovered as feed stock from various industries' by-products and wastes using potential technologies. As a result, current trends are shifting attention to the sustainable valorisation of food sector waste management and by-products utilization. Thus, the circular economy principles have been applied to the field of food science. The aim of the circular economy is to ensure environmental protection and promote economic development while minimizing the environmental impact of food production. All of these aspects of the circular economy, at present, have become a challenging area of research for by-product valorisation as well. Hence, this review aims to highlight the emerging trends in the efficient utilization of food industry waste and by-products by focusing on innovative encapsulation techniques and controlled release mechanisms of bioactive compounds extracted from food industry waste and by-products. This review also aims to suggest future research directions, and addresses regulatory and toxicity considerations, by fostering knowledge dissemination and encouraging eco-friendly approaches within the food industry. This review reveals the role of encapsulation strategies for the effective utilization of bioactive compounds extracted from food industry waste and by-products. However, further research is needed to address regulatory and toxicity considerations of encapsulated bioactive compounds and health-related concerns.

Thermodynamic modelling of cements clinkering process as a tool for optimising the proportioning of raw meals containing alternative materials

The valorisation of waste or by-products in Portland clinker production is a promising alternative for developing sustainable cements. The complexity of the chemical reactions during clinkering demands an adequate dosing method that considers the effect of feedstock impurities to maximise the potential substitution of natural resources by waste or by-products, while guaranteeing the clinker reactivity requirements. This study proposes a raw meal proportioning methodology for optimising co-processing of natural feedstocks with alternative raw materials in clinker production, intending to reduce the content of natural raw materials needed, while promoting an optimal clinker reactivity. A thermodynamic modelling sequence was developed considering the variability of raw materials composition and heating temperatures. The model was then validated by comparing simulation outcomes with results reported in previous studies. An experimental case study was conducted for validation of the proposed method using a spent fluid catalytic cracking catalyst (SFCC), a by-product from the oil industry as an alternative alumina source during clinkering. The modelling simulations indicated that substitution of natural feedstocks by 15 wt% SFCC promotes the formation of reactive clinkers with more than 54% tricalcium silicate (C3S). Mixes with the potential to form the highest C3S were then produced, and heating microscopy fusibility testing was applied for evaluating the clinkers’ stability. The main factors governing the reactivity and stability of the clinker phases were the melt phase content, alumina modulus, and formation of C3S and dicalcium silicate (C2S). The self-pulverisation of clinker during cooling was observed in selected mixes, and it is potentially associated with high viscosity and low Fe content in the melt phase. The proposed framework enables optimisation of the dosing of raw meals containing alternative alumina-rich feedstocks for clinker production and allows a deeper interpretation of limited sets of empirical data.

Biodegradation of agave Comiteco bagasse by Pleurotus spp.: a source of cellulases useful in hydrolytic treatment to produce reducing sugars.

This study aimed to determine the production parameters of five strains of Pleurotus spp. during their cultivation on agave Comiteco bagasse, as well as the feasibility of using cellulolytic extracts to produce reducing sugars in the same bagasse. After cultivation, the basidiome production parameters varied between 41.2 and 65.7% (biological efficiency), 0.17 and 0.30 (yield), 0.60 and 0.90% (production rate), 16.4 and 41.1% (Bioconversion) and 9.4 and 21.3g (mean mushroom weight). At day 15 of growth, P. djamor showed the highest β-glucosidase activity (43.95 ± 4.5IU/g); on day 33. The same strain had the highest endoglucanase activity (21.12 ± 0.5IU/ml). Both extracts were partially purified, and the kinetic parameters Vmax and Km were estimated (20.83µmole/ml sec and 232.01 µmole/ml for β-glucosidase and 685.01 µmole/ml sec and 1,240.34µmole/ml for endoglucanase). In the enzymatic hydrolysis assay, the highest concentration of reducing sugars (43.13 ± 1.09g/L; 0.21g/g bagasse) was obtained by a mixture of the two partially purified extracts acting synergistically after 48h and with a pH adjustment. The results suggest that the use of agave Comiteco bagasse for cultivating edible mushrooms while obtaining cellulolytic extracts is an alternative treatment for waste reduction and valorization of agro-industrial by-products.

Agrofood Waste and By-Product Valorization, Extraction, and Characterization of Pectin from the Waste Biomass Fruit Peel of Aframomum angustifolium Using Response Surface Methodology as Alternative Sources of a Functional Pectin

Applications of pectin in the food industry are strongly influenced by their source, structures, and extraction methods, which affect their functionalities. This research aims to extract and assess pectin’s physicochemical and functional properties from waste biomass peels of Aframomum angustifolium as an alternate source using acid (AAE) and microwave extraction (MAE) methods. Pectin extracted from A. angustifolium was compared based on yield, color, moisture, equivalent weight, methoxyl content (MC), and degree of esterification (DegE). Response surface experimental design was used to study the effect of the extraction process pectin such as the yield and the DegE. MAE had a significantly higher % yield of 4.74 ± 0.1% and a lower equivalent weight of 852.49 ± 16.59 mg/ml than AAE with 3.09 ± 0.03% and 882.1 ± 9.04 mg/ml, respectively, with light brown color. The lower moisture contents of 6.5%, MC of 33.06%, and DegE of 67.96% were obtained by MAE compared to 6.9%, 31.85%, and 66.61%, respectively, for AAE. The time and temperature had a positive significant effect ( p < 0.05) on % pectin yield for MAE and AAE, while time and pH squared had a negative. Temperature squared had a negative significance on % DE, and pH had a positive significance using AAE and MAE. Optimal conditions for MAE obtained were the power of 555.18W, pH of 2.79, and time of 40.69 min with optimum desirability of 0.829, while for acid extraction, the temperature of 72.95°C, pH of 2.31, and time of 142.55 min with the desirability of 0.88. A highly functionalized pectin can be extracted from the peels of A. angustifolium as an alternate source.

Pork organs as a potential source of flavour-related substances

The increase in world population has generated a higher demand for quality proteins, increasing the production in meat industry but also the generation of thousands of tons of by-products, with a negative economic and environmental impact. The valorisation of slaughterhouse by-products by giving by-products a new use as food ingredient is one of the best strategies to add value while reducing environmental damage. Flavour is one of the most influential parameters in the purchasing decision of consumers, and in meat products it is mostly influenced by the content in free amino acids and nucleotides. In this study, the potential of 4 pork organs (liver, kidney, lung, and brain) as a source of flavour-related substances was investigated. Liver proved to be the organ showing the highest content of free and total amino acids related to taste, while kidney was the organ with the highest content of umami nucleotides. The results of the Taste Activity Value indicated that umami, sweet, and bittersweet amino acids are main responsible for the taste of the organs. On the other hand, the synergy between amino acids and nucleotides in relation with umami taste was determined, showing liver and kidney the best values in Equivalent Umami Content. In addition, the antioxidant activity of the organs was determined, and liver and kidney showed the highest antioxidant activity in all assays (p < 0.05). In conclusion, pork organs, especially liver and kidney, may be good candidates to be used as raw materials to produce functional flavouring ingredients.

Energy and environmental performance assessment of reused PET bottles panels for building thermal insulation solutions

The construction industry is responsible for several environmental impacts, such as high consumption of raw materials and energy, significant contributions to global CO2 emissions, and waste production. Furthermore, concerns regarding waste and by-products valorization have been growing recently, particularly for plastic waste, whose integration into building materials components is under investigation. Different applications of polyethylene terephthalate (PET) have emerged, particularly for nonstructural purposes, with potential benefits as thermal insulation solutions, showing that further studies should be conducted for a more detailed analysis and characterization of this type of building solutions. In this context, the current study contributes to the thermal and environmental performance characterization of alternative materials composed of PET bottle panels filled with soil, water, and air. An experimental evaluation of the thermal performance and a Life Cycle Assessment (LCA) were conducted considering the horizontal and vertical positions of the bottle panels. The lowest values of the thermal transmission coefficient were observed for the PET bottles filled with soil, achieving 0.46 W/m2°C for the vertical position. Regarding LCA, the panel with empty bottles showed the best environmental performance, which was justified by the fact that no filling process was considered. Considering that filling bottles with air or soil results in similar environmental impacts, it can be concluded that PET bottles filled with soil provide the best thermal and environmental alternative.

Trash to Treasure: An Up-to-Date Understanding of the Valorization of Seafood By-Products, Targeting the Major Bioactive Compounds.

Fishery production is exponentially growing, and its by-products negatively impact industries' economic and environmental status. The large amount of bioactive micro- and macromolecules in fishery by-products, including lipids, proteins, peptides, amino acids, vitamins, carotenoids, enzymes, collagen, gelatin, chitin, chitosan, and fucoidan, need to be utilized through effective strategies and proper management. Due to the bioactive and healthy compounds in fishery discards, these components can be used as functional food ingredients. Fishery discards have inorganic or organic value to add to or implement in various sectors (such as the agriculture, medical, and pharmaceutical industries). However, the best use of these postharvest raw materials for human welfare remains unelucidated in the scientific community. This review article describes the most useful techniques and methods, such as obtaining proteins and peptides, fatty acids, enzymes, minerals, and carotenoids, as well as collagen, gelatin, and polysaccharides such as chitin-chitosan and fucoidan, to ensure the best use of fishery discards. Marine-derived bioactive compounds have biological activities, such as antioxidant, anticancer, antidiabetic, anti-inflammatory, and antimicrobial activities. These high-value compounds are used in various industrial sectors, such as the food and cosmetic industries, owing to their unique functional and characteristic structures. This study aimed to determine the gap between misused fishery discards and their effects on the environment and create awareness for the complete valorization of fishery discards, targeting a sustainable world.

Actividad antifúngica in vitro de extractos de ramas/hojas de arándano y semilla de palta contra Botrytis sp.

Currently, the search for eco-friendly products has become more intensive, guiding the agro-industry towards more sustainable practices. Obtaining bioactive compounds with antifungal activity represents a viable source of fungicides for postharvest use, since up to now there is still a high demand for chemical fungicides in the industry. The effect of two aqueous extracts of acetone origin obtained from blueberry branches and leaves (mixture) and avocado seed was evaluated. This plant material is part of agro-industrial waste from the production process of the company Camposol S.A. To determine the concentration of polyphenols, the Folin Ciocalteu method was used and for the antioxidant capacity, the DPPH radical method. The tentative identification of compounds present in each extract was performed using UHPLC-DAD-ESI/MS. The acetone extracts were dried and re-suspended in water. Three concentrations (5, 25 and 50 mg/mL) were used on the inhibition of spore germination and mycelial growth of Botrytis sp. 55% inhibition of spores was obtained after 24 h of incubation and 19% inhibition in growth mycelial at 7 days of incubation. This research contributes to the valorization of by-products, giving them added value, encouraging the development and implementation of new products based on plant material with important bioactive potential for the emerging sector of Agro-industry.

Valorization of apple pomace by-products from the juice processing industry using pressurized liquid technology

Bagasse is a by-product of the juice processing industry with a high water content, high acidity, and rapid deterioration. Considering apple pomace, approximately 21 million tons are produced annually, rich in dietary fiber, vitamins, reducing sugars, and phenolic compounds. In this sense, conventional extraction (CE) and pressurized liquid extraction (PLE) were compared in terms of pectin yield, total phenolic compounds, and Ferric ion Reducing Antioxidant Power (FRAP) using a Box-Behnken factorial design considering the variables temperature, pressure, and Solvent/Feed (S/F) ratio. CE occurred with citric acid solution 6.5% (w/v) under stirring for 2 h. PLE occurred continuously with a flow rate of 5 mL min−1 with citric acid solution 6.5% (w/v) for 40 min. The highest pectin yield was 20.05% at 110 °C, 20 MPa, and S/F 10. Further optimized conditions led to a total phenolic compounds yield of 16.3 ± 0.3 mg GAE g−1 and FRAP of 137 ± 5 µmol TE g−1. Although pectin yield was higher for EC (25.27 ± 1.78%), total phenolic compounds content and FRAP were higher for PLE. High contents of glucose and fructose were found in all extracts. However, only high temperatures facilitated the hydrolysis and release of ellagic acid. Furthermore, a kinetic study demonstrated that 91.94% of total pectin was extracted with 11.30 min by PLE. Statistical analysis indicated that the effect of the linear and quadratic terms of the variable S/F ratio was significant for all responses evaluated. Therefore, the design approach efficiently obtained high pectin yields, providing information that allows expansion to pilot and industrial scales.

Valorization of Olive Mill Byproducts: Recovery of Biophenol Compounds and Application in Animal Feed.

This study aimed to recover the phenols from olive oil mill wastewater, a major pollutant of the oil industry, by using spray-drying technology to produce a new feed with a nutraceutical value for animal feed supplementation and to evaluate its effect on the productivity and nutritional quality of ewe milk. Forty-five Sarda ewes in late lactation (150 ± 2 d) and with homogeneous live weight (52 ± 1.5 kg) were randomly allotted into three groups and fed with three dietary treatments containing increasing levels of polyphenols: 0% (C), 0.1% (T0.1), and 0.2% (T0.2) of dry matter. No effect of the dietary treatments was found on the milk yield and composition. Interestingly, milk urea content (p < 0.0001) and somatic cell counts (p < 0.001) decreased as the level of polyphenols inclusion in the diet increased. The inclusion of phenols (0.2% of dry matter) in the diet of sheep was effective in increasing the vaccenic (C18:1 trans-11) and rumenic acid (C18: cis-9 trans-11) levels, which are beneficial for human health. Finally, the recovery of polyphenols via spray-drying technology and their incorporation into a new fortified feed can be a valid strategy for naturally improving the nutritional value of milk while valorizing an oil industry byproduct, reducing environmental impact, and promoting waste reuse that is in line with circular economy principles.

Cold Plasma Technology for Tomato Processing By-Product Valorization: The Case of Tomato Peeling and Peel Drying

The tomato processing industry is focused on product yield maximization, keeping energy costs and waste effluents to a minimum while maintaining high product quality. In our study, cold atmospheric plasma (CAP) pretreatment enhanced tomato processing to facilitate peelability, a specific peeling process, and enhance peel drying. Peeling force analysis determined that CAP pretreatment of whole tomatoes improved peelability under the conditions used. The specific peeling force after CAP treatment decreased by more than three times. It was observed that cold atmospheric plasma pretreatment reduced the duration of infrared drying of tomato peels by 18.2%. Along with that, a positive effect on the reduction of the specific energy consumption of peel drying was shown for CAP-pretreated tomato peels. The obtained data show that the technology of cold atmospheric plasma pretreatment, in particular, when processing whole tomatoes and tomato peels, has a promising application in industry, as it can significantly reduce the specific energy consumption for peeling and drying procedures.

Kinetic Ultrasound-Assisted Extraction as a Sustainable Approach for the Recovery of Phenolics Accumulated through UVA Treatment in Strawberry By-Products.

Ultrasound-assisted extraction (UAE) is an efficient and sustainable method for extracting bioactive compounds from agro-industrial by-products. Moreover, it has been reported that ultraviolet A (UVA) radiation can induce the biosynthesis and accumulation of bioactive phenolic compounds. This study optimized the efficiency of ultrasound-assisted extraction (UAE) for recovering ultraviolet A (UVA)-induced phenolic compounds in strawberry by-products (RF-N). The impact of three factors (solid-liquid ratio, ethanol concentration, and ultrasound power) on total phenolic compound (TPC) kinetics using Peleg's model was investigated. The developed model showed a suitable fit for both RF-N and strawberry by-products treated with UVA (RF-E). The optimal UAE conditions obtained were of a 1:30 ratio, 46% ethanol, and 100% ultrasound power, resulting in an average yield of 13 g total phenolics kg-1. The bioaccessibility of phenolic compounds during in-vitro digestion was 36.5%, with agrimoniin being the predominant compound. UAE combined with UVA treatment increased the bioactivity of RF extracts, displaying significant anti-proliferative effects on HT29 and Caco-2 cancer cell lines, as well as anti-inflammatory potential and cellular antioxidant activity. The ultrasound proved to be a sustainable and effective technique for extracting phenolic compounds from RF, contributing to the valorization of strawberry agro-industrial by-products, and maximizing their nutraceutical potential.

Application of Agri-Food By-Products in the Food Industry

Every year, the global food industry produces a significant number of wastes and by-products from a variety of sources. By-products from the food-processing sector are produced in large quantities, and because of their undesirable qualities, they are frequently wasted, losing important resources. In order to pursue a circular economy that refers to waste reduction and effective waste management, by-products valorization recently received increased interest. By-products are rich in bioactive compounds and can be used in various industrial applications for health promotion and nutritional benefits. A novel step in its sustainable application is the use of these inexpensive waste agri-food by-products to create the value-added products. The present review intended to summarize the different types of agro-industrial by-products and their properties and highlight their nutritional composition and potential health benefits. Applications of agri-food by-products in foods as well as the potential health and sustainability implications of by-products in food products were also covered. According to research, agri-food by-products can be added to a variety of food to increase their bioactive profile, fiber content, and antioxidant capacity while maintaining good sensory acceptability. Overall, the sustainability of the agri-food chain and consumer health can both benefit from the use of agri-food by-products in food formulation.

Novel dual-function GC/MS aided ultrasound-assisted hydrodistillation for the valorization of Citrus sinensis by-products: phytochemical analysis and anti-bacterial activities

A huge-amount of citrus by-products is being wasted every-year. There is a high-need to utilize these by-products with high-efficiency. This study focuses on the essential oil (EO) isolation from the zest of Citrus sinensis (CS) by-products, using a novel dual-function gas-chromatography mass-spectrometry optimized ultrasound-assisted hydrodistillation-prototype (DF-GC/MS-HUS). The CS-EO was GC-analyzed by MS-detector (GC/MS) and optimized by flame-ionization detector (GC/FID). Ultrasound-assisted hydrodistillation (HUS) had a dual-function in CS-EO isolation by utilizing an adequate-energy to break-open the oil-containing glands, and by functioning-as a dispersing-agent to emulsify the organic-phase. The most effective DF-GC/MS-HUS optimized-conditions were isolation under 38 °C and 10 min of 28.9 Hz sonication. The main-components of CS-EO were limonene, β-myrcene, and α-pinene (81.32%, 7.55%, and 4.20%) in prototype, compared to (60.23%, 5.33%, and 2.10%) in the conventional-method, respectively. The prototype CS-EO showed natural antibacterial-potentials, and inhibited the bio-film formation by Staphylococcus aureus, Listeria monocytogenes, and E. coli more-potent than the conventional-method. Compared to conventional-method, the prototype-method decreased the isolation-time by 83.3%, lowered energy-consumption, without carbon-dioxide production, by reducing isolation-temperatures by more-than half, which protected the thermolabile-components, and increased the quantity by 2514-folds, and improved the quality of CE-EO composition and its antibacterial-potentials. Therefore, the DF-GC/MS-HUS prototype method is considered a novel green-technique that minimized the energy-utilization with higher-efficiency.

Stimulating circular economy in the food industry: a comparative analysis of the governance strategies in Greece and Armenia

The success of transformation to a circular economic model mainly depends on effective government interventions. The objective of this paper is to reveal the implementation schemes, actors in charge, and funding mechanisms of the circular economy action plan in Greece. Additionally, a comparison has been made concerning the waste management governance practices in Armenia given a few distinct political, social, economic and behavioral characteristics common to both countries. Special emphasis was put on the food industry, since it generates a large amount of waste annually with limited by-product valorization and recycling rate. A comprehensive document analysis has been conducted with deductive or concept-driven approach using the software Atlas.ti. Research results highlighted several deficiencies existing within the policy papers and a set of recommendations covering critical success factors such as education, finance, cooperation, market development, monitoring, and evaluation related to the system change were offered. By addressing these deficiencies, policymakers may ensure an environment conducive to circularity practices and facilitate the transition to a more sustainable and resource-efficient economy.

Diverse uses of valuable seafood processing industry waste for sustainability: a review.

Seafoods are rich in untapped bioactive compounds that have the potential to provide novel ingredients for the development of commercial functional foods and pharmaceuticals. Unfortunately, a large portion of waste or discards is generated in commercial processing setups (50-80%), which is wasted or underutilized. These by-products are a rich source of novel and valuable biomolecules, including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, vitamins, carotenoids, chitin, chitosan and biopolymers. These fish components may be used in the food, cosmetic, pharmaceutical, environmental, biomedical and other industries. Furthermore, they provide a viable source for the production of biofuels. As a result, the current review emphasizes the importance of effective by-product and discard reduction techniques that can provide practical and profitable solutions. Recognizing this, many initiatives have been initiated to effectively use them and generate income for the long-term sustainability of the environment and economic framework of the processing industry. This comprehensive review summarizes the current state of the art in the sustainable valorisation of seafood by-products for human consumption. The review can generate a better understanding of the techniques for seafood waste valorisation to accelerate the sector while providing significant benefits.

Development and Characterization of N/S-Carbon Quantum Dots by Valorizing Greek Crayfish Food Waste

The valorization of food industry byproducts has become a significant issue worldwide because of the drive towards a circular economy. The “zero waste target” in human activities seems to be a dominant objective in the design of future products by enterprises. In this work, food waste from the crayfish processing industry was converted into useful products (quantum dots), as nowadays, biowaste-derived materials tend to be more attractive than conventionally produced materials with a similar structure due to their lower production costs and environmentally friendly development processes. More specifically, shell waste from the crayfish industry was treated hydrothermally and, after a freeze-drying process, was transformed to useful quantum dots. Instrumental and chemical techniques, such as XRD, SEM-EDS, AFM, XPS, elemental analysis, fluorescence spectroscopy, TG, Microtox bioassay, and DPPH antioxidant activity, were employed to characterize the final product. The results indicated the existence of thermally stable spherical particles, with a diameter of 5–8 nm, which were mainly composed of carbon, oxygen, nitrogen, calcium, and sulfur. Their external surface was rough and rich with various functional groups that further contributed to their overall optical properties. The final product presented low ecotoxicity, as studied by the Microtox assay. The superior antioxidant activity of this product compared to other similar materials reported elsewhere renders it a potential material for, e.g., food packaging applications. In addition, for the first time, N/S-Carbon QDs were applied as an antioxidant/antibacterial agent for strawberry preservation, showing promising results as the coated strawberries maintained their color and weight for three consecutive days with no mold growth observed on their surface.

Green recovery optimization of phenolic compounds from “Spinoso sardo” globe artichoke by-products using response surface methodology

The reuse and valorization of agri-food by-products is a pivotal activity in the pursuit of a circular model that can improve sustainability and efficiency of agri-food production. During artichoke processing, 60–80% of the biomass produced by the plant consists of inedible fractions, which nevertheless represent a natural source of high value-added compounds, such as phenolics. In this study, response surface methodology was applied to investigate and optimize the amount of ethanol and the reduction of extraction time to achieve the maximum yield of polyphenols and flavonoids from artichoke stems, leaves, and bracts, by using two extraction methods, namely maceration and ultrasound-assisted extraction. Overall, phenolic compounds were most concentrated in extracts obtained from the stems, followed by those derived from the bracts and leaves, with the percentage of ethanol being the most influential factor. After applying the optimization criteria, the best factor setting to achieve maximum extraction yields and strong antioxidant capacities was: 53% ethanol for stems, 45% for leaves, and 50% for bracts and 60 min for all by-products in the case of maceration; 10 min for stems and leaves with 42 and 20% of ethanol, respectively, and 41 min and 64% ethanol for bracts in the case of ultrasound-assisted extraction. Comparison between the two techniques evidenced that maceration was significantly more efficient, but similar recoveries were obtained with ultrasound-assisted extraction in shorter extraction time and lower ethanol consumption. Therefore, using this unconventional method to convert Spinoso Sardo artichoke by-products into bioactive ingredients with interesting industrial applications could be a viable strategy to reduce food losses and mitigate related environmental impacts.

Sustainable valorization of co-products from asparagus cultivation by obtaining bioactive compounds.

Asparagus cultivation generates every year a significant amount of by-products that consist of root and frond. Leaving these residues on the fields after harvesting negatively affects the following asparagus crops, since they release autotoxic (allelopathic) substances into the soil, whose accumulation causes that asparagus yields gradually decrease over the years, becoming an unprofitable crop in a period of about 10 to 15 years. This phenomenon is known as decay and forces the entire asparagus plantation to be lifted (abandoned). On the other hand, once a certain plantation has been lifted, it is not profitable to immediately re-plant new asparagus plants, since the yields that are achieved are never more than half of normal ones. It is necessary to wait an average of 4 or 5 years before replanting asparagus in these lands. This phenomenon is known as the replanting problem, and causes the need to continually search for new land for growing asparagus. Another added problem for farmers is that the elimination of those plant residues from asparagus cultivation entails significant economic costs. For all these reasons, it is essential to seek alternatives for the management of that waste that improve the sustainability of the crop within the scope of the circular economy. In this context, this work proposes the valorization of asparagus by-products by obtaining bioactive compounds. Main objectives of the present work include: i) phytochemical analyses of asparagus fronds and roots; ii) obtaining bioactive extracts, with distinct technological and nutritional functionalities, by using an environmentally sustainable extraction process, easy to implement in the practice of a food industry and with methods compatible with food use. Characterization of asparagus by-products shown that fronds had an average flavonoid content of 2.637 ± 0.014 g/Kg fresh weight, which is up to 5-6 times higher than that of the spears; and roots contained up to 10 times more saponins (2.25 g/Kg fresh weight), which were accompanied by lower quantities of phenolic acids (368 mg/Kg fresh weight). Statistical analysis revealed that those phytochemical contents were mainly determined by location and phase of the vegetative cycle, whereas genetic factors did not significantly influence them. Based on the results of the present work, the proposal for the recovery and valorization of asparagus by-products is based on obtaining two bioactive extracts, the first being an antioxidant extract enriched in flavonoids, with an average yield of 10.7 g/Kg fresh frond and a flavonoid richness of 17%; and the second, a saponins extract with an average yield of 10.3 g/Kg fresh root and a richness of 51%. These natural extracts have great techno-functional potential in the agri-food industry and some of them are already being tested as additives in the preparation of soups, breads and meat products.