Recent Advances in Natural Polyphenol Research.

Polyphenols are secondary metabolites produced by plants, which contribute to the plant's defense against abiotic stress conditions (e.g., UV radiation and precipitation), the aggression of herbivores, and plant pathogens. Epidemiological studies suggest that long-term consumption of plant polyphenols protects against cardiovascular disease, cancer, osteoporosis, diabetes, and neurodegenerative diseases. Their structural diversity has fascinated and confronted analytical chemists on how to carry out unambiguous identification, exhaustive recovery from plants and organic waste, and define their nutritional and biological potential. The food, cosmetic, and pharmaceutical industries employ polyphenols from fruits and vegetables to produce additives, additional foods, and supplements. In some cases, nanocarriers have been used to protect polyphenols during food processing, to solve the issues related to low water solubility, to transport them to the site of action, and improve their bioavailability. This review summarizes the structure-bioactivity relationships, processing parameters that impact polyphenol stability and bioavailability, the research progress in nanocarrier delivery, and the most innovative methodologies for the exhaustive recovery of polyphenols from plant and agri-waste materials.

Sustainable bioconversion of potato peel wastes into ethanol and biogas using organosolv pretreatment.

Potato processing industries generate considerable amounts of residues, i.e., potato peel wastes (PPW). Valorization of PPW for bioethanol and biogas production via a biorefining process was investigated in this study. Organosolv pretreatment was performed on the PPW using 50-75% (v/v) ethanol solution at 120-180 °C with/without the presence of 1% (w/w) H2SO4 (as a catalyst). After the pretreatment, the solvent, i.e., ethanol, was recovered by distillation. Catalyzed organosolv pretreatment using 50% (v/v) ethanol at 120 °C followed by enzymatic hydrolysis resulted in a high hydrolysate yield of 539.8 g glucose/kg dry PPW that was successfully fermented to 224.2 g ethanol/kg dry PPW. To recover more energy, the liquid fraction of the pretreatment remained after solvent recovery and the unhydrolyzed solids that remained from the enzymatic hydrolysis were anaerobically digested. From each kg of dry PPW, the anaerobic digestion produced 57.9 L biomethane. Thus, the biorefinery comprising ethanolic organosolv pretreatment, solvent recovery, enzymatic hydrolysis, ethanolic fermentation, and anaerobic digestion of residues was produced 8112 kJ energy per kg of dry PPW.

Valorization of Agri-Food Wastes as Sustainable Eco-Materials for Wastewater Treatment: Current State and New Perspectives.

The paper addresses environmental protection by valorizing an important agri-food waste category, namely fruit and vegetables with focusing on the main characteristics regarding consumption, waste quantities, and ways for valorizing these materials. Thus, vast research was undertaken in order to emphasize the main commodities and their potential application as adsorbents for organic and inorganic pollutants. The main methods or treatment techniques applied for the valorization of eco-materials as adsorbents were presented and the principal efficiency results were indicated. The advantages and disadvantages of using these eco-materials as adsorbents in wastewater treatment were revealed and future recommendations were established. According to the international statistics, the most purchased and consumed five commodities were studied regarding waste generations as potential conversion into eco-materials with an adsorbent role for water pollutants. Thus, the performances for adsorbents based on fruit wastes (such as citrus, banana, apples, grapes, mango) and vegetable wastes (such as potatoes, tomatoes, cabbage, carrots, cauliflower, and/or broccoli) were studied and highlighted in this research.

Nanotechnologies: An Innovative Tool to Release Natural Extracts with Antimicrobial Properties.

Site-Specific release of active molecules with antimicrobial activity spurred the interest in the development of innovative polymeric nanocarriers. In the preparation of polymeric devices, nanotechnologies usually overcome the inconvenience frequently related to other synthetic strategies. High performing nanocarriers were synthesized using a wide range of starting polymer structures, with tailored features and great chemical versatility. Over the last decade, many antimicrobial substances originating from plants, herbs, and agro-food waste by-products were deeply investigated, significantly catching the interest of the scientific community. In this review, the most innovative strategies to synthesize nanodevices able to release antimicrobial natural extracts were discussed. In this regard, the properties and structure of the starting polymers, either synthetic or natural, as well as the antimicrobial activity of the biomolecules were deeply investigated, outlining the right combination able to inhibit pathogens in specific biological compartments.

Production of arachidonic acid by Mortierella alpina using wastes from potato chips industry.

AIMS: This research aimed to determine the potential use of wastes from the potato chips industry as a carbon source to develop an economical culture medium for the production of biomass, lipids and arachidonic acid (ARA) by Mortierella alpina. METHODS AND RESULTS: A synthetic culture medium was optimized using a Plackett-Burman and central composite rotatable design, and used as a base to evaluate and characterize the potential use of wastes from the potato chips industry as carbon sources for the production of biomass, lipids and ARA by M. alpina. The waste was selected among other solid and liquid hydrolysed residues/by-products, and local low-cost alternatives for nitrogen sources were also evaluated. After 6 days of fermentation, the biomass concentration reached 20 g l-1 with 40% of total lipids, and a 35% ARA content in the lipids fraction. Savings in production were calculated using a sensitivity analysis for the alternative culture medium in different scenarios. CONCLUSIONS: This study showed a 7% savings in culture media expenses in the production of ARA-enriched biomass of M. alpina, compared to the conventional synthetic culture medium, when waste from the potato chips industry was used as an alternative source of carbon and macro/microelements, supplemented with a low-cost yeast extract alternative. SIGNIFICANCE AND IMPACT OF THE STUDY: The demonstration of the use of potato chips wastes as a low-cost carbon source for the biomass, lipids and ARA production, suggesting an eco-friendly alternative for the use of agri-food wastes for valuable metabolites production.

Comparative growth potential of thermophilic amylolytic Bacillus sp. on unconventional media food wastes and its industrial application.

Amylases take part with vital role in industries such as food, fermentation; starch processing, textile and paper etc. Increasing amylases demand, high nutrient expenditure and environmental pollution have forced to utilize agro-industrial residues as a low-cost feedstock for enzyme production. In present study, three soil samples were collected from agro-industrial waste dumping areas in District Faisalabad. Ten thermophilic bacterial isolates were separated at 55 °C on the basis of colonial morphology, three isolates (F6, F11, F17) showed prominent zone of clearance applying iodine test on starch agar plates. Bacterial isolate F-11 showed highest amylase activity with DNS method and molecularly identified through 16S RNA sequencing as Bacillus sp. with Accession number MH917294. Four unconventional food wastes (banana, lemon, mango and potato) pretreated with 0.8% sulphuric acid concentrations taking 1000 g/L weight released the highest sugars contents and phenolic components. Maximum amylase activity i.e. 29.23 mg/ml was achieved in mango waste at, 40 °C, with pH 6.0 and 0.17% nitrogenous source adding 8% inoculum size (2 days old) using Response Surface Methodology (RSM) for optimization. Crude amylase confirmed its efficiency in starch hydrolysis that suggested it as potential candidate for application in starch industries.

Comparative Assessment of Antioxidant, Anti-Diabetic and Cytotoxic Effects of Three Peel/Shell Food Waste Extract-Mediated Silver Nanoparticles.

BACKGROUND: The natural food waste peels/shells discarded as waste materials are ample sources of natural bioactive compounds. The natural food waste mediated silver (Ag) nanoparticle (NPs) synthesis will be advantageous over chemical synthesis. MATERIALS AND METHODS: Using the various phytochemical-rich ripe P. americana peel (PAP), fresh Beta vulgaris peel (BVP), and rawArachis hypogaea shell (AHS) extracts, the bio-synthesis of PAP-AgNPs, BVP-AgNPs, and AHS-AgNPs, respectively, were carried out and its characterization was completed by standard procedures. The three biosynthesized AgNP's multiple biological effects were accomplished by evaluating their cytotoxicity, antidiabetic, and antioxidant effects. RESULTS: The biosynthesis of the three generated Ag nanoparticles was confirmed through UV-vis spectrum analysis while the X-ray diffraction outlines revealed the generated AgNPs nature. The morphological structure and elemental information of the three AgNPs were obtained through SEM (scanning electron microscopy) and EDX (energy-dispersive X-ray) study. Multiple biological assays exhibited that the three generated AgNPs have significant cytotoxic, antidiabetic, and moderate antioxidant activity. In a comparative analysis, the PAP-AgNPs displayed higher anticancer potential than BVP and AHS-AgNPs, whereas AHS-AgNPs exhibited a higher antidiabetic effect with the lowest IC50 value (1.68 µg/mL) than PAP and BVP AgNPs. All three generated AgNPs displayed moderate antioxidant effects, among them BVP-AgNPs were more effective than PAP and AHS AgNPs. More than two effects of the three biosynthesized AgNPs specifies that they have ample perspective in therapeutic applications in pharmaceutical and other related industries in controlling cancer and diabetes.

Experimental and feasibility study of spent coffee grounds upscaling via pyrolysis towards proposing an eco-social innovation circular economy solution.

There is a need for eco-social business models in the food waste sector that are more cascading and circular-based, while having economic, environmental and social benefits. The aim of this study is to bring insights and data of spent coffee grounds large-scale slow pyrolysis, to seize new opportunities for eco-innovative solutions in the circular economy, by identifying upcycling opportunities for resource recovery of this waste. First, an experimental study was conducted, and a set of pyrolysis experiments were carried out at a temperature range from 450 to 750 °C, with a heating rate of 50°/s, under helium atmosphere, to explore the products' yields and the best process' conditions. Second, an economic study was conducted for a standalone pyrolysis plant fueled with the spent coffee grounds streams from coffee shops of a city with 150,000 inhabitants, in central Greece, aiming at the cost and the profitability of the endeavor estimation. The calculations were based on the features of a slow pyrolysis rotary kiln technology designed at Aristotle University, and co-developed with an Irish company, under the funding of an EU LIFE+ project. For an estimated capacity of 2566 t/yr of SCG, the revenue of the endeavor was calculated at 47€/t of SCG. The economic indicators ROI and POT (ROI = 0.24, POT = 2.6), are very positive, suggesting pyrolysis of SCG as an efficient circular economy management solution, providing an eco-social innovation business in the coffee shop industry, engaging also consumers in the circular economy.

Study of chemical composition and nutritional values of vegetable wastes in Bangladesh.

The present study was conducted with the objectives of determining the chemical composition and nutritional value of vegetable waste (VW) of households and the marketplace for their suitability as ruminant feed. The crude protein, total digestible nutrients and extent of rumen degradability of dry matter (DM) of VW of households were 140.0 g kg-1, 0.668 and 0.855, respectively; while those of the marketplace were 169.0 g kg-1, 0.633 and 0.80, respectively. The levels of chromium and lead in each respectively, was 13.27 and 1.53 ng kg-1DM; and 31.01 and 5.71 ng kg-1DM. The total aflatoxins in VW of households was 3.08 µg kg-1DM, and undetectable in VW from the marketplace. Considering the chemical composition and safety parameters studied, VW could preliminary be considered as animal feed. The feeding of processed marketplace VW (VWP) at 275 g kg-1DM of a diet or 0.76% of live weight (LW) to growing bulls, replacing 50% of a concentrate mixture as supplement to a Napier silage diet for a period of 34 days reduced the total DM intake (0.0276 vs 0.0343 LW) without any significant (P > 0.05) changes in DM or protein digestibility. Blood urea levels (19.5 vs 23.67 mg dl-1), and serum creatinine levels (1.37 vs 1.08 mg dl-1) differed significantly (P > 0.05) between the two groups but were within normal physiological ranges. Therefore, it may be concluded that the level of incorporation of VWP would be less than 50% replacement of the concentrate in the diet. Further research is required to determine optimum inclusion levels in ruminant diets.

Analysis of glycosylated flavonoids extracted from sweet-cherry stems, as antibacterial agents against pathogenic Escherichia coli isolates.

The aim of this study was to evaluate the bioactivity of flavonoids extracted from sweet-cherry stems which are often used by a traditional system of medicine to treat gastro-intestinal and urinary tract infections but lacking any consistent scientific evidence; moreover the information about the class of phenolics, their content and the potential bioactivity of such material is very scarce. Thus, in this context, we have set a research study in which we evaluated the profile and content of phenolics extracted from sweet-cherry stems through a conventional (70ºC and 20 min) and ultrasound assisted extraction (40 kHz, room temperature and 20 min). The extracts were phytochemically characterized by using an HPLC-DAD-UV/VIS system and assayed by an in vitro minimum inhibitory concentration (MIC) bioassay against Escherichia coli isolates. Simultaneously, the total antioxidant activities were measured using the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS•+) radical cation assay. Our results indicate that sweet-cherry stems have a high content of sakuranetin, ferulic acid, p-coumaric acid, p-coumaroylquinic acid, chlorogenic acid and its isomer neochlorogenic acid. Their average levels were highly affected by the extraction method used (p<0.001). The same trend was observed for total antioxidant activity and MIC values. The extracts produced with ultrasounds presented both, a higher total antioxidant activity and a lower minimum inhibitory concentration. Statistical analyses of our results showed a significant correlation (p<0.01) of total antioxidant activity and minimum inhibitory concentration with phenolics present in the extracts studied. Thus, we can conclude that cherry stems can be further exploited to purify compounds and produce coproducts with enhanced biologically added value for pharmaceutical industry.

Molecular and enzymatic characterization of alkaline lipase from Bacillus amyloliquefaciens E1PA isolated from lipid-rich food waste.

Bacillus amyloliquefaciens E1PA is a lipase-producing strain that was originally isolated from lipid-rich food waste, and the production of its lipase was found to be induced by vegetable oils. The E1PA lipase was successfully expressed and secreted in a heterologous Escherichia coli host and was ultimately purified. The conserved pentapeptide motif Ala-His-Ser-Met-Gly was observed at positions 108-112. The purified recombinant lipase was stable over a pH range of 4.0-11.0 at 40 °C and exhibited maximal activity at pH 10. The recombinant E1PA lipase hydrolyzed a wide range of acyl esters (C4-C18). However, the highest activity (3.5 units mg(-1)) was observed when the p-nitrophenyl ester of myristate (C14) was used as a substrate. Compared to the lipases produced by Bacillus spp., the E1PA lipase displayed a structural molecular mass excluding the leader sequence (19.22 kDa) and a pI (9.82) that were similar to those reported for B. amyloliquefaciens lipases and lipase subfamily I.4 but that were quite distinct from those of lipase subfamily I.5 (approximately 43 kDa, pI 6). These results suggested that Bacillus lipases are closely related. Although the recombinant E1PA lipase digested only certain oils, the wild-type E1PA lipase degraded a variety of oils, including blended and re-used cooking oils. The recombinant and wild-type forms of the E1PA lipase were able to digest heterogeneous lipid-rich food waste at similar levels; this result suggests that this lipase can function even when it solely consists of its structural enzyme component. The enzyme exhibited lipid hydrolysis ability as either an intracellular domain of the recombinant protein or an extracellular domain secreted by the E1PA strain. However, the recombinant lipase showed higher activity than the wild-type E1PA lipase, indicating that the recombinant protein from E. coli possessed effective lipase activity. Thus, the inducible alkaline E1PA lipase exhibited the ability to act on a broad spectrum of substrates, and the effective form produced in the heterogeneous host can be further developed for several applications, such as biodiesel production and lipase production.

Characterization of typical household food wastes from disposers: fractionation of constituents and implications for resource recovery at wastewater treatment.

Food wastes with typical US food composition were analyzed to characterize different constituents in both particulate and soluble phases i.e., solids, chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD), nitrogen (N), phosphorus (P). Relationships between various pollutants were also investigated using 50 samples. One gram of dry food waste generated 1.21 g COD, 0.58 g BOD5, 0.36 g Total SS, 0.025 g Total N, and 0.013 g Total P. Distribution of constituents between particulate and aqueous phases indicated that 40% of COD and 30% of nitrogen were present in soluble form. Relative mass ratios of COD and nitrogen to solids were three to five times higher in particulates than in aqueous phase. However, COD/N ratios were higher in aqueous form than particulates at 63:1 versus 42:1. Detailed relationships between parameters showed that COD, nitrogen, and phosphorus in particulates are 200%, 3.6%, and 3.5% of the volatile suspended solids.