Valorization of the major agrifood industrial by-products and waste from Central Macedonia (Greece) for the recovery of compounds for food applications

Exploring the Bioactive Content of Liquid Waste and Byproducts Produced by Two-Phase Olive Mills in Laconia (Greece): Is There a Prospect for Added-Value Applications?

The use of a two-phase decanter (TwPD) for olive-oil extraction produces wastes and byproducts (a small volume of water from oil washing, olive leaves from the defoliator, and a high moisture pomace which can be destoned) that contain valuable bioactive compounds, such as phenolics and/or triterpenic acids. So far, there is no (water) or limited information (leaves and the destoned pomace fraction) on their content of bioactives, especially triterpenic acids. To contribute to the characterization of such streams from cultivars of international interest, in the present study, samples obtained from five mills from the region of Laconia (from one or two harvests) in Greece, where Koroneiki cv dominates, were screened for phenols and/or triterpenic acids. The leaves and pomace were dried at two temperatures (70 °C and/or 140 °C), and the pomace was also destoned before analysis. The liquid wastes contained low amounts of total (TPC) phenols (<140 mg gallic acid/L), hydroxytyrosol (<44 mg/L), and tyrosol (<33 mg/L). The olive leaves varied widely in TPC (12.8-57.4 mg gallic acid/g dry leaf) and oleuropein (0.4-56.8 mg/g dry leaf) but contained an appreciable amount of triterpenic acids, mainly oleanolic acid (~12.5-31 mg/g dry leaf, respectively). A higher drying temperature (140 vs. 70 °C) affected rather positively the TPC/oleuropein content, whereas triterpenic acids were unaffected. The destoned pomace TPC was 15.5-22.0 mg gallic acid/g dw, hydroxytyrosol 3.9-5.6 mg/g dw, and maslinic 5.5-19.3 mg/g dw. Drying at 140 °C preserved better its bioactive phenols, whereas triterpenic acids were not influenced. The present findings indicate that TwPD streams may have a prospect as a source of bioactives for added-value applications. Material handling, including drying conditions, may be critical but only for phenols.

Proximate Composition and Fatty Acid Profile of Gilthead Seabream (Sparus aurata) Fed with Pelvetia canaliculata-Supplemented Diets: An Insight towards the Valorization of Seaweed Biomass

Seaweeds are a sustainable source of protein and lipids that may be used to replace fish by-products in aquaculture feed. This study aimed at using the macroalgae Pelvetia canaliculata as an ingredient in gilthead seabream (Sparus aurata) feed, either as freeze-dried powder or as algae residue (waste) that was obtained after the supplementation of sunflower oil. The formulated diets and the fish muscle were analyzed concerning the proximate composition and the fatty acid profile. The health lipid indices hypocholesterolemic/hypercholesterolemic (h/H), atherogenic (AI), thrombogenic (TI), as well as n-3/n-6 and polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) ratios were calculated. Additionally, the peroxidizability index (PI) was determined. No differences were observed in the proximate composition of fish muscle regardless of the diet used. Fish fed a diet supplemented with 10% of algae waste (W10) stand out for the highest content in oleic acid (C18:1 n-9), and the lowest in both linoleic (C18:2 n-6) and palmitic (C16:0) fatty acids. All fish samples showed values of health lipid indices within the limits recommend for a nutritional balanced diet. These results highlight that fish fed diets supplemented with P. canaliculata are sources of healthy lipids that might be consumed on a regular basis to prevent cardiovascular diseases.

Grape By-Products as Feedstuff for Pig and Poultry Production

Grape by-products are exceptional options for replacement of conventional and unsustainable feed sources, since large amounts are generated every year from the winery industry. However, the majority is wasted with severe environmental and economic consequences. The present review aimed to evaluate the effects of grape by-products on pig and poultry growth performance. The most recent literature was reviewed using ScienceDirect and PubMed databases and the results of a total of 16 and 38 papers for pigs and poultry, respectively, were assessed. Fewer studies are documented for pig, but the incorporation of grape by-products up to 9% feed led to an improvement in growth performance with an increase in average daily gain. Conversely, lower levels (<3% feed) are needed to achieve these results in poultry. The beneficial effects of grape by-products on animal performance are mainly due to their antioxidant, antimicrobial, and gut morphology modulator properties, but their high level of cell wall lignification and content of polyphenolic compounds (e.g., tannin) limits nutrient digestion and absorption by monogastric animals. The use of exogenous enzymes or mechanical/chemical processes can provide additional nutritional value to these products by improving nutrient bioavailability. Overall, the valorization of grape by-products is imperative to use them as feed alternatives and intestinal health promoters, thereby contributing to boost circular agricultural economy.

Rice Industry By-Products as Adsorbent Materials for Removing Fluoride and Arsenic from Drinking Water—A Review

In drinking water, high concentrations of fluoride and arsenic can have adverse effects on human health. Waste deriving from the rice industry (rice husk, rice straw, rice bran) can be promising adsorbent materials, because they are (i) produced in large quantities in many parts of the world, (ii) recoverable in a circular economy perspective, (iii) at low cost if compared to expensive conventional activated carbon, and (iv) easily manageable even in developing countries. For the removal of fluoride, rice husk and rice straw allowed to obtain adsorption capacities in the range of 7.9–15.2 mg/g. Using rice husk for arsenic adsorption, excellent results were achieved with adsorption capacities above 19 mg/g. The best results both for fluorides and arsenic (>50 mg/g) were found with metal- or chemical-modified rice straw and rice husk. Identifying the next steps of future research to ensure the upscaling of biochar from recovered by-products, it is fundamental to perform: (i) tests on real waters for multicomponent adsorption; (ii) experiments with pilot plants in continuous operation; (iii) cost analysis/real applicability of modification treatments such as metal coupling or chemical synthesis; (iv) more studies on the biochar stability and on its regeneration or recovery after use.

Valorization of Tomato Waste as a Source of Carotenoids

Fast-accumulating scientific evidence from many studies has revealed that fruits and vegetables are the main source of bioactive compounds; in most cases, wastes and byproducts generated by the food processing industry present similar or a higher content of antioxidant compounds. In recent years, the ever-growing amount of agricultural and food wastes has raised serious concerns from an environmental point of view. Therefore, there is an increasing interest in finding new ways for their processing toward safely upgrading these wastes for recovering high-value-added products with a sustainable approach. Among food waste, the abundance of bioactive compounds in byproducts derived from tomato suggests possibility of utilizing them as a low-cost source of antioxidants as functional ingredients. This contribution gives an overview of latest studies on the extraction methods of carotenoids from tomato waste, along with an evaluation of their antioxidant activity, as well as their industrial applications.

Analysis of Promotion Policies for the Valorization of Food Waste from Industrial Sources in Taiwan

Growing concern about circular bioeconomy and sustainable development goals (SDGs) for the valorization of food waste has raised public awareness since 2015. Therefore, the present study focused on the promotion policies and regulatory measures for the valorization of mandatory recyclable food waste from industrial sources in Taiwan, including the animal/plant production farms and food-processing plants. According to the official data on the annual statistics during the period of 2015–2019, it showed that the food waste from alcoholic beverage manufacturers (i.e., lees, dregs, or alcohol mash) and oyster farms (i.e., waste oyster shell) accounted for about half (about 250,000 metric ton) of industrial food waste generation in Taiwan. In order to effectively reduce the burdens on incinerators/landfills and their environmental impacts, the central governing agencies jointly promulgated some regulatory measures for promoting the production of biobased products from the industrial food waste valorization like animal feed, soil fertilizer, and bioenergy. These relevant acts include the Waste Management Act, the Fertilizer Management Act, the Feed Management Act, and the Renewable Energy Development Act. In addition, an official plan for building the food waste bioenergy plants at local governments via anaerobic digestion process, which was estimated to be completed by 2024, was addressed as a case study to discuss their environmental and economic benefits.

Circular Economy Models in Agro-Food Systems: A Review

Around the world, interest is growing in the circular economy in response to the current unsustainable model of production and consumption based on increased use and depletion of resources. This paper provides a review of the academic literature on the circular economy in agri-food systems, with the aims of understanding its main characteristics and perspectives, and summarizing and discussing the literature in this field. This review provides a deeper understanding of the opportunities provided by the circular economy as a solution to the current need to reduce the environmental impacts of business-as-usual economic systems and the state of the art of the circular economy in the academic debate. The results are discussed based on the chosen topic-core investigated in this review: business model and organization management, food loss and waste along the supply chain, analytical tools for the circular economy, stakeholder acceptance of the circular economy, and mitigation strategies and political approach. The findings show the need for the implementation of cleaner production models and consequent increases in stakeholder responsibilities and awareness, from both producers and consumers, as well as the need for the implementation of suitable policies and tools.

An Overview on Sustainability in the Wine Production Chain

Despite the great relevance of sustainable development, the absence of a shared approach to sustainable vitiviniculture is evident. This review aimed to investigate sustainability along the entire wine chain, from primary production to the finished wine, with specific attention to three key dimensions of sustainability (environmental, social, and economic) and relating measures. Therefore, it was decided to: investigate the ways in which sustainability is applied in the various stages of the production chain (wine growing, wineries, distribution chain, and waste management); analyse the regulations in force throughout the world and the main labelling systems; provide numerical information on sustainable grapes and wines; study the objective quality of sustainable wines and that perceived by consumers, considering that it affects their willingness to pay. The research highlighted that rules and regulations on organic production of grapes and wines are flanked by several certification schemes and labelling systems. Although sustainable wines represent a niche in the market, in recent years, there has been an increase in vineyards conducted with sustainable (mainly organic and biodynamic) methods, and a consequent increase in the production of sustainable wines both in traditional and emerging producing countries. Although (or perhaps precisely for this reason) no significant differences in quality are found among sustainable and conventional wines, consumers are willing to pay a premium for sustainably produced wines. This finding should encourage wineries to both put in place environmental activities and intensify their communication.

Deriving valorization of phenolic compounds from olive oil by-products for food applications through microencapsulation approaches: a comprehensive review

Nowadays, olive oil consumption is correlated to many health benefits, essentially due to the presence of antioxidants, especially phenolic compounds, which fostered its intensive production worldwide. During olive oil extraction, through continuous or discontinuous processes, many olive oil by-products are generated. These by-products constitute an environmental problem regarding its management and disposal. They are phytotoxic and biotoxic due to their high content of phenolic compounds, presenting contrastingly relevant health benefits due to their potent radical scavenging activities. In the framework of the disposal and management of olive oil by-products, treatment, and valorization approaches are found. As currently, the majority of the valorization techniques applied have a null market value, alternative strategies for the obtainment of innovative products as fortified foods are being investigated. The recovery and valorization strategies of olive oil by-products may comprise extraction and further encapsulation of bioactive compounds, as an innovative valorization blueprint of phenolic compounds present in these by-products. The majority of phenolic compounds present in olive oil by-products possess limited application on the food industry since they are promptly amended by environmental factors like temperature, pH, and light. Consequently, they must be protected previously ending in the final formulation. Prior to foods fortification with phenolic-rich extracts obtained from olive oil by-products, they should be protected through microencapsulation approaches, allowing a sustained release of phenolic compounds in the fortified foods, without losing their physicochemical properties. The combined strategies of extraction and microencapsulation will contribute to promoting the sustainability of the olive oil sector and aid the food industry to obtain reinvented added-value products.

Valorization of byproducts from tropical fruits: Extraction methodologies, applications, environmental, and economic assessment: A review (Part 1: General overview of the byproducts, traditional biorefinery practices, and possible applications)

Tropical fruits represent one of the most important crops in the world. The continuously growing global market for the main tropical fruits is currently estimated at 84 million tons, of which approximately half is lost or wasted throughout the whole processing chain. Developing novel processes for the conversion of these byproducts into value-added products could provide a viable way to manage this waste problem, aiming at the same time to create a sustainable economic growth within a bio-economy perspective. Given the ever-increasing concern about sustainability, complete valorization through a bio-refinery approach, that is, zero waste concept, as well as the use of green techniques is therefore of utmost importance. This paper aims to report the status on the valorization of tropical fruit byproducts within a bio-refinery frame, via the application of traditional methodologies, and with specific attention to the extraction of phenolics and carotenoids as bioactive compounds. The different types of byproducts, and their content of bioactives is reviewed, with a special emphasis on the lesser-known tropical fruits. Moreover, the bioactivity of the different types of extracts and their possible application as a resource for different sectors (food, pharmaceutical, and environmental sciences) is discussed. Consequently, this review presents the concepts of tropical fruit biorefineries, and the potential applications of the isolated fractions.

Effect of Feed Supplemented with Selenium-Enriched Olive Leaves on Plasma Oxidative Status, Mineral Profile, and Leukocyte DNA Damage in Growing Rabbits

Simple Summary

Olive trees (Olea europaea L., Oleaceae) are among the most extensively cultivated crops in the Mediterranean countries (98% of the world’s olive production) and are used for oil extraction or table olives, whereas the residues from pruning (olive leaves and wood) and extraction process (olive pomace) are considered waste or by-products. Furthermore, many agronomic practices, such as foliar spray administration of selenium used to reduce the water stress damage of olive trees, could further improve the nutritional value of these “wastes”. The use of by-products as part of the rabbit diet can be a very effective example of recovery of healthy molecules while at the same time a way of developing a more sustainable production system. Accordingly, the idea of the present research is to administer the by-product “olive leaves” to growing rabbits to improve their health status and partially solve the problem of waste disposal of olive trees.

Abstract

This study investigated the effect of a dietary combination of selenium and olive leaves on rabbit health status in order to evaluate the potential use of these combinations as functional ingredients in feed and food. Sixty weaning rabbits were fed with three diets: control feed (C), control feed + 10% normal olive leaves (OL), or olive leaves enriched in Se (2.17 mg Se/kg d.m.; SeOL). The plasma mineral profile, antioxidant status, and leukocyte DNA damage were determined. Inorganic Se was the most abundant form in the OL diet, while the organic one was higher in SeOL than C and OL. A similar trend was found in the plasma. Protein oxidation showed higher values in both supplemented groups; in addition, dietary Se led to a significant improvement (+40%) in ferric reducing ability of plasma (FRAP). A marked reduction in DNA damage (9-fold) was observed in the SeOL group compared to C. The combination of selenium and olive leaves in the diet of growing rabbits increased plasma SeMet and FRAP and reduced leukocyte DNA damage.

Finding solutions for agricultural wastes: antioxidant and antitumor properties of pomegranate Akko peel extracts and β-glucan recovery

Pomegranate peels are the major by-products of the processing of pomegranate juice. Scientific research studies have shown that pomegranate peels are an extraordinary source of bioactive compounds, most of which can be converted into value added products. From this point of view, the present study was carried out with the aim of providing a solid basis for the use of whole pomegranate peels (Akko variety) as a source of nutraceutical compounds, such as β-glucans. Moreover, acetone (S1) and methanolic (S2) extracts, obtained in the preliminary stage of the β-glucan isolation procedure, have been tested for their antioxidant and antitumor activities. The total phenolic content and phenolic profile of S1 and S2 were determined. S1 and S2 exhibited a significant DPPH scavenging activity, with an IC50 value for S1 1.5-fold lower than that for the standard Trolox. Both S1 and S2 extracts possess in vitro ROS scavenging activity toward 3T3-L1 murine fibroblasts and Hek-293 human embryonic kidney epithelial cells and antiproliferative activity towards human breast MCF-7 and uterine HeLa cancer cells.

Ultrasound as a Rapid and Low-Cost Extraction Procedure to Obtain Anthocyanin-Based Colorants from Prunus spinosa L. Fruit Epicarp: Comparative Study with Conventional Heat-Based Extraction

An ultrasound rapid and low-cost procedure for anthocyanin-based colorants from Prunus spinosa L. fruit epicarp was developed, and the advantages were compared with conventional heat-based extraction. To obtain the conditions that maximize anthocyanins' extraction, a response surface methodology was applied using the variables of time, temperature, and ethanol content, in the case of heat extraction, whereas for ultrasound assisted extraction, temperature was replaced by ultrasound power. Two anthocyanin compounds were identified by HPLC-DAD-ESI/MS-namely, cyanidin 3-rutinoside and peonidin 3-rutinoside. The responses used were the extraction yield and the content of the identified anthocyanins. Ultrasound extraction was the most effective method at 5.00 ± 0.15 min, 400.00 ± 32.00 W, and 47.98% ± 2.88% of ethanol obtaining 68.60% ± 2.06% of extracted residue, with an anthocyanin content of 18.17 mg/g (extract-basis) and 11.76 mg/g (epicarp-basis). Overall, a viable green process was achieved that could be used to support pilot-scale studies for industrial production of anthocyanin-based colorants from P. spinosa fruit epicarp.

Selenium maintains Ca2+ homeostasis in sheep lymphocytes challenged by oxidative stress

Selenium (Se) is an essential element in human and animal diets, based upon a widespread range of beneficial effects that are primarily due to its antioxidant properties. While Se can be associated to anti-cancer and anti-diabetic activities, reproductive efficiency, and enhancement of the immune system, the mechanistic details of the corresponding biological processes are still largely elusive. To avoid deficiencies and increase bioavailability, Se it is generally supplied to livestock through Se-supplemented feeds or forage plants fertilized with inorganic Se. While the relationship between Ca²⁺ and ROS (reactive oxygen species) is well known, only a few studies have addressed the possible involvement of Se in the control of cytosolic Ca²⁺ in oxidative stress. The results on Ca²⁺ homeostasis were obtained adding exogenous Se in the form of SeO₄^2- to sheep lymphomonocytes cultured in vitro. In particular, Se strongly attenuated 1mM H₂O₂-induced alteration of intracellular [Ca²⁺]_C as well as the entry of extracellular Ca²⁺ into the cells with comparable EC50 values for sodium selenate accounting to 1.72 and 2.28 mM, respectively. In an ex vivo trial, it was observed that Ca²⁺ homeostasis can effectively be rescued in sheep lymphomonocytes exposed in vivo to a Se concentration of approximately 1.9 mM, that was achieved by feeding sheep with olive leaves previously sprayed with 500 mg/plant Na-selenate. Thus the results obtained suggest that the mode of action of selenium markedly influenced Ca²⁺-related signaling events. Furthermore, results clearly reveal that the protective effect of Se on Ca²⁺ homeostasis under oxidative challenge can be clearly and effectively achieved through an appropriate dietary regimen obtained also in a circular economy logic using pruning of olive trees treated to reduce tree drought stress.

Production of Nutritious Flour from Residue Custard Apple (Annona squamosa L.) for the Development of New Products

Currently, the fruit processing industry generates a high volume of waste in fruits that have not reached a quality standard for consumption or by-products generated throughout the production process. To reduce this waste, mitigating measures, such as reuse in food formulations, have been proposed. In this work the custard apple bagasse flour (Annona squamosa L.) (CAB) was produced and incorporated into cookie formulations in different proportions (5 to 50%) evaluating its acceptability. The CAB flour was characterized by physicochemical analysis, proximate composition, mineral analysis, determination of the phenolic content, and antioxidant capacity. The results of the physicochemical and proximate characterizations show that the processed flour presents values and specifications suitable for food formulations. The mineral composition of the CAB flour responds to more than 20% of the daily intake of nutrients, highlighting the Cu, Fe, Mn, Zn, Ca, and Mg. The composition of phenolic compounds for CAB flour and cookies formulations presented values ranging from 200 to 658 mg GAE/100 g, similar to flour and formulations prepared of residues tropical fruit, while DPPH• inhibition showed a variation of 9.68–10.75%. Cookies made from the CAB flour showed high acceptability making the flour promising in the nutritional incorporation in food formulations.

Reutilization of discarded biomass for preparing functional polymer materials

Biomass is abundant and recyclable on the earth, which has been assigned numerous roles to human beings. However, over the past decades, accompanying with the rapid expansion of man-made materials, such as alloy, plastic, synthetic rubber and fiber, a great number of natural materials had been neglected and abandoned, such as straw, which cause a waste of resource and environmental pollution. In this review, based on introducing sources of discarded biomass, the main composition and polymer chains in discarded biomass materials, the traditional treatment and novel approach for reutilization of discarded biomass were summarized. The discarded biomass mainly come from plant wastes generated in the process of agriculture and forestry production and manufacturing processes, animal wastes generated in the process of animal husbandry and fishery production as well as the residual wastes produced in the process of food processing and rural living garbage. Compared with the traditional treatment including burning, landfill, feeding and fertilizer, the novel approach for reutilization of discarded biomass principally allotted to energy, ecology and polymer materials. The prepared functional materials covered in composite materials, biopolymer based adsorbent and flocculant, carrier materials, energy materials, smart polymer materials for medical and other intelligent polymer materials, which can effectively serve the environmental management and human life, such as wastewater treatment, catalyst, new energy, tissue engineering, drug controlled release, and coating. To sum up, the renewable and biodegradable discarded biomass resources play a vital role in the sustainable development of human society, as well as will be put more emphases in the future.