Unraveling the potential nutritional benefits of fermented date syrup waste: Untargeted metabolomics and carbohydrate metabolites of in vitro digested fraction

Valorization of fruit by-products is a crucial area of research for the development of innovative bio-based products. This study investigated the physicochemical properties and health-promoting benefits of date syrup waste, both fermented by Pichia cecembensis or Pichia kudriavzevii (FDSW), and unfermented (CDSW). Metabolomics profiles of these samples were identified post in vitro digestion. FDSW exhibited 42 volatile compounds, including 9 new ones, and contained (-)-epicatechin, tyrosol, and gallic acid. Bioaccessible fractions of FDSW demonstrated substantial α-amylase inhibition, with percentages of 40.7 % and 53.9 %, respectively. FDSW displayed superior cytotoxicity against Caco2 and MCF-7 cancer cell lines, with an average of ∼75 % and 56 %, respectively. Untargeted metabolomics analysis revealed an increase in secondary metabolites, totaling 27 metabolites. LC-QTOF analysis of bioaccessible carbohydrate metabolites in FDSW identified two phytochemical groups, alkaloids, and terpenoids. This study underscores the potential of FDSW for producing value-added bio-based products with desirable characteristics and health benefits.

Blend of Baru (Dipteryx alata Vog.) By-Products as Nutritive and Healthy Food Ingredients: Chemical Composition, Functional Properties and Application in Plant-Based Burger

The chemical composition, antioxidant capacity and functional properties of mixtures of baru by-products, named baru food ingredients (BFI), were investigated and applied in a plant-based burger formulation. BFI were prepared from wasted baru by-products - partially defatted baru nut cake and baru pulp plus peel. A plant-based burger was developed and its chemical composition, antioxidant capacity, cooking and texture parameters were determined. BFI1 (50% partially defatted baru nut cake + 50% baru pulp plus peel) had the highest content of carbohydrate (31.9%), and dietary fibre (28.3%). BFI2 (75% partially defatted baru nut cake + 25% baru pulp plus peel) and BFI3 (90% partially defatted baru nut cake + 10% baru pulp plus peel) showed high concentration of protein and dietary fibre, and BFI3 had the highest protein content (29.5%). All BFI showed high concentration of total phenolics (402-443 mg GAE/100 g). Replacing textured pea protein of control burger (PPB) with 35% of BFI3 in the formulation of baru protein burger (BPB) resulted in a low-fat product (2.9%), with protein content (19.2%) comparable to the PPB (15.9%) and the commercial burger (mixed plant proteins - 16.3%). The BPB also showed a higher concentration of dietary fibre (4.9%) and phenolic compounds (128 mg GAE/100 g) than the control burger. BPB's cooking yield was the highest among the tested burgers. BPB had a softer texture when compared to other burgers. Baru food ingredients can be used as nutritive ingredients of health-promoting foods, especially in plant-based products, such as burger and meat analogues, or in hybrid meat products. BPB showed a healthy and nutritious profile.

Valorization and Repurposing of Citrus limetta Fruit Waste for Fabrication of Multifunctional AgNPs and Their Diverse Nanomedicinal Applications

Herein we propose an ecofriendly process for the biofabrication of AgNPs by applying fruit waste of Citrus limetta. The aqueous extracts from the peels of the fruit were used as green chelating and stabilizing agents. Structural, optical, vibrational, morphological, and magnetic properties were established using UV-Vis (ultraviolet visible spectroscopy), XRD (X-rays diffraction), FTIR (Fourier transformed infrared spectroscopy), EDS (energy dispersive spectroscopy), SEM (scanning electron microscopy), ESR (electron spin resonance), and PPMS (physical property management system), while the thermal properties were established using TGA/DTG (thermal gravimetric analysis/derivative thermogravimetry). XRD pattern revealed intense peaks with single-phase purity, while the Debye-Scherrer approximation revealed an average crystallite size of 33.18 nm. The W-H plot revealed the size of 55.2 nm and strain 2.68 × 10-4. FTIR spectra revealed the involvement of different functional groups and major IR vibrations were observed at 2329 cm-1, 2092 cm-1, 1794 cm-1, 1268 cm-1, and 754 cm-1. TGA/DTG revealed major weight loss events at 240 °C and 360 °C. SEM revealed spherical or quasi-spherical morphology, while EDS confirmed the presence of elemental silver. The M-H behavior for all measurement temperature shows diamagnetic behavior. Electron spin resonance (ESR) revealed a high proportion of free electrons. Furthermore, the pharmacognostic and nanomedicinal potential CL-AgNPs was established using multiple in vitro and in vivo bioassays. The in vivo wound healing assays in mice revealed excellent healing potential which were similar to positive control. The percent wound healing is reported to be 93% on the 14th day of incision after application of CL-AgNPs. Bioassays were performed to assess enzyme inhibition potential of the CL-AgNPs for Alzheimer disease and antidiabetic applications. The AChE and BChE potential of the CL-AgNPs was highest at 1000 µg mL-1, i.e., 92% and 56%, respectively. The α-glucosidase inhibition potential for the CL-AgNPs was higher as compared to the α-glucosidase, while the DPPH free radical scavenging was reported to be 70% to 11% at varying concentrations between 1000 and 62.5 µg mL-1. Overall, our results indicate that the waste fruit peels can be a sustainable and eco-friendly resource of synthesis of the multifunctional nanoparticles.

Bioconversion of citrus waste into mucic acid by xylose-fermenting Saccharomyces cerevisiae

Mucic acid holds promise as a platform chemical for bio-based nylon synthesis; however, its biological production encounters challenges including low yield and productivity. In this study, an efficient and high-yield method for mucic acid production was developed by employing genetically engineered Saccharomyces cerevisiae expressing the NAD+-dependent uronate dehydrogenase (udh) gene. To overcome the NAD+ dependency for the conversion of pectin to mucic acid, xylose was utilized as a co-substrate. Through optimization of the udh expression system, the engineered strain achieved a notable output, producing 20 g/L mucic acid with a highest reported productivity of 0.83 g/L-h and a theoretical yield of 0.18 g/g when processing pectin-containing citrus peel waste. These results suggest promising industrial applications for the biological production of mucic acid. Additionally, there is potential to establish a viable bioprocess by harnessing pectin-rich fruit waste alongside xylose-rich cellulosic biomass as raw materials.

Garbage to Gains: The role of biochar in sustainable soil quality improvement, arsenic remediation, and crop yield enhancement

Threats of soil quality deterioration and metal pollution have inflicted several parts of the world, apart from the need for surplus crop production. The investigation used biochar prepared from waste biomasses such as wheat and rice straw, kitchen waste, leaf litter, Lantana camara, orange peel, and walnut shell to improve soil quality, reduce As pollution, and enhance plant growth. Biochars were amended at doses of 0%, 2.5%, 5%, and 7.5% and conditioned for 3 months. At a 7.5% dose, the maximum improvements in cation exchange capacity (a 62% increase), anion exchange capacity (a two-fold increase), bulk density (a 31% decrease), porosity (a 32% increase), water holding capacity (an 86% increase), soil respiration (a 32% increase), total carbon (a two-and-a-half-fold increase), total nitrogen (an eleven-fold increase), total phosphorus (3 times rise), total potassium (a two-and-a-half-fold increase), mobile As (a 38% decrease), leachable As (a 53% decrease), and bio-available As (a 56% decrease) were observed. Further, pot experiments revealed augmented biomass growth (61% and 177%), increased length (71% and 209%), and decreased As accumulation (56% and 55%) in the above-ground parts of Bengal gram and coriander plants, respectively. Therefore, the application of biochar was found to enhance the physico-chemical properties of soil, reduce As contamination levels, and improve crop growth. The study recommends using waste biomasses to prepare eco-friendly biochars, which could contribute to advancing sustainable agriculture and the circular economy.

The potential of industrial sludge and textile solid wastes for biomass briquettes with avocado peels as a binder

Producing biomass briquettes from industrial solid wastes is a more environmentally friendly way to provide alternative energy and is essential for Ethiopia to satisfy its growing energy needs while also ensuring efficient waste management in the expansion of industrial parks. The main objective of this study is to produce biomass briquettes from a mixture of textile sludge and cotton residue using avocado peels as a binder. Textile solid waste, avocado peels, and sludge were dried, carbonized, and turned into powder to make briquettes. Briquettes made from the mixture of industrial sludge and cotton residue were combined in various ratios: 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50 with the same amount of the binder. Briquettes were then made using a hand press mold followed by sun-drying for two weeks. The moisture content, calorific value, briquette density, and burning rate of biomass briquettes ranged from 5.03 to 8.04%, 11.19 to 17.2 MJ/kg, 0.21 to 0.41 g/cm3, and 2.92 to 8.75 g/min, respectively. The results revealed that the briquette produced from a 50:50 ratio of industrial sludge to cotton residue was the most efficient. The inclusion of avocado peels as a binder enhanced the briquette's binding and heating properties. Thus, the findings suggested that mixing various industrial solid wastes with fruit wastes could be an effective means of making sustainable biomass briquettes for domestic purposes. Additionally, it can also promote proper waste management and provide young people with employment prospects.

Enhanced production of acetic acid through bioprocess optimization employing response surface methodology and artificial neural network

In this study, acetic acid bacteria (AAB) are isolated from fruit waste and cow dung on the basis of acetic acid production potential. The AAB were identified based on halo-zones produced in the Glucose-Yeast extract-Calcium carbonate (GYC media) agar plates. In the current study, maximum acetic acid yield is reported to be 4.88 g/100 ml from the bacterial strain isolated from apple waste. With the help of RSM (Response surface methodology) tool, glucose and ethanol concentration and incubation period, as independent variable showed the significant effect of glucose concentration and incubation period and their interaction on the AA yield. A hypothetical model of artificial neural network (ANN) was also used to compare the predicted value from RSM. Acetic acid production through the biological route can be the sustainable and clean approach to utilizing food waste in circular economy approach.

A comparison of reactor configuration using a fruit waste fed two-stage anaerobic up-flow leachate reactor microbial fuel cell and a single-stage microbial fuel cell

Food waste generation and its consequent environmental impacts are increasing due to rapid urbanization, the global population, and associated food demand. Microbial fuel cells (MFCs) are a sustainable technology through which this food waste can be treated and used to produce bioelectricity. This study used two MFC configurations, a two-stage anaerobic up-flow leachate reactor MFC and a single-stage MFC, comparing the potential to treat solid fruit waste and fruit waste leachate. The two-stage MFC showed a higher potential to remove substrate at a shorter time compared to single-stage MFC. In 30 days, the two-stage anaerobic up-flow leachate reactor had a power density of 221 mW/m². It was able to remove more total solids (by 95 %), volatile solids (by 70 %), total chemical oxygen demand (by 83 %), soluble chemical oxygen demand (by 87 %), and carbohydrates (by 33 %) compared to the single-stage MFC. However, the single-stage MFC showed higher coulombic efficiency (by 86.7 %) compared to the two-stage MFC. The efficiency of single-stage MFC improved by adding buffer and maintaining a neutral pH level of the substrate. The results of this study emphasize the importance of reactor design and demonstrate that MFC can be a viable technology to generate bioenergy from food waste.

DIVERISTY and enzymatic potential of indigenous bacteria from unexplored contaminted soils in Faisalabad

Bacteria residing in contaminated waste soil degrade and utilize organic and inorganic material as a source of nutrients as well as reduce environmental contamination through their enzymatic machinery. This enzymatic potential of indigenous bacteria can be exploited at industrial level through detailed screening, characterization, optimization and purification. In present study, diversity and enzymatic potential of indigenous bacteria was investigated through qualitative and quantitative screening methods from unexplored contaminated soil waste sites in Faisalabad. Shannon diversity (H') index revealed that twenty-eight soil samples from four contaminated sites were highly diverse of amylase, protease and lipase producing bacteria. Maximum protease producing bacteria were detected in fruit waste (1.929 × 10⁷), whereas amylase and lipase producing bacteria were found in industrial (1.475 × 10⁷) and (5.38 × 10⁶), in household waste soil samples. Most of the indigenous bacterial isolates showed potential for multiple enzymes. An isolate OC5 exhibited capability for amylase production and optimization at a wider range of cultural conditions; pH (6-8), temperature (25 °C, 37 °C, 45 °C), incubation time (24-72 h), and NaCl concentrations 0.5-13%, using (1%) starch and lactose as substrates. An isolate OC5 was identified by molecular identification and phylogenetic analysis showed 99% sequence similarity with Bacillus spp. ANOVA was used to analyzed all data statistically. This study enhances the importance of initial screening and reporting of industrially potent indigenous bacteria from unexplored contaminated waste soils. In future, indigenous bacteria in contaminated wastes may be good candidates to solve various environmental pollution problems.

Enhancement in functional stability of microbial endoglanases produced using paddy straw via treatment with manganese oxide based porous nanocomposite synthesized from mixed fruit waste

Microbial cellulases are the enzymes used in numerous industrial biotechnological applications. Efficiency of celluloytic cocktails plays a key role in the conversion of biomass into biofuels, but limited production, high cost and low efficiency are the main obstacles to sustainable biorefining. The current work aims to establish a feasible approach for boosting the production of fungal endoglucanse (EG) and its functional stability utilizing nanocomposite materials based on manganese oxide. Herein, aqueous extract from mixed fruit waste was used to synthesize the nanocomposite sample, which was subsequently subjected to several characterization techniques for analysis. Following the solid-state fermentation of paddy straw, and by employing 75 mg nanocomposite, 192 IU/gds EG was produced under the optimal conditions, while 19 IU/gds FP and 98 IU/gds BGL production were recorded. The crude EG enzyme treated with nanocomposite also shows complete stability at pH 5.0 for 3.5 h while retaining thermal activity at 70 °C for 4 h.

Sustainable approaches on industrial food wastes to value-added products - A review on extraction methods, characterizations, and its biomedical applications

The concept of zero waste discharge has been gaining importance in recent years towards attaining a sustainable environment. Fruit processing industries generate millions of tons of byproducts like fruit peels and seeds, and their disposal poses an environmental threat. The concept of extracting value-added bioactive compounds from bio-waste is an excellent opportunity to mitigate environmental issues. To date, significant research has been carried out on the extraction of essential biomolecules, particularly polysaccharides from waste generated by fruit processing industries. In this review article, we aim to summarize the different extraction methodologies, characterization methods, and biomedical applications of polysaccharides extracted from seeds and peels of different fruit sources. The review also focuses on the general scheme of extraction of polysaccharides from fruit waste with special emphasis on various methods used in extraction. Also, the various types of polysaccharides obtained from fruit processing industrial wastes are explained in consonance with the important techniques related to the structural elucidation of polysaccharides obtained from seed and peel waste. The use of seed polysaccharides as pharmaceutical excipients and the application of peel polysaccharides possessing biological activities are also elaborated.

Does the presence of heavy metal and catechol contaminants in organic waste challenge the physiological performance of the bioconverter Hermetia illucens?

The increased human activities and the worldwide population growth are constantly increasing the production of solid wastes. Over the years, waste management has thus become a prominent issue for several companies and municipalities, and several engineering techniques have been developed over the years in order to convert wastes into other solid materials or fuels. Yet, several techniques are important contributors to environmental pollution, and biological-based solutions have thus become progressively very popular. In particular, insect-based conversion of organic wastes represent eco-friendly tools, and the growth and development of insect species such as the black soldier fly have been tested and improved for a large diversity of organic wastes. However, organic wastes, including food wastes, may contain several pollutants such as heavy metals and catechol which could affect the bioconversion efficiency by incurring physiological costs that would be undetectable at the organismal level, i.e. have null to little effects on the life cycle of Hermetia illucens. In this context, assessments of antioxidant capacities can provide a rapid and low-cost evaluation of the capability of insects to handle exposure to heavy metals and catechol. Here, we aimed at measuring the physiological responses of the black soldier fly H. illucens grown on food wastes (kitchen, fruit or vegetable wastes) contaminated by cadmium, iron, lead or catechol. Biomarkers of oxidative stress (concentrations of hydrogen peroxide and protein carbonyls), non-enzymatic total antioxidant capacity (ascorbic acid amounts) and activity of enzymatic antioxidants (activities of superoxide dismutase and polyphenoloxidase) were measured from the gut of the larvae. We found no evidence of deleterious impacts of food waste contamination by catechol or heavy metals on H. illucens. In most experimental treatments, the array of physiological endpoints we measured for evaluating the degree of oxidative stress experienced by the larvae remained similar to controls. Possible physiological effects were reported for cadmium and catechol only, which tended to increase the oxidation of proteins and hydrogen peroxide in the larvae. Finally, our results suggested that the nature of the food waste could equally affect the physiological responses of the insect.

Technoeconomic and life cycle analysis of soluble dietary fiber concentrate production from waste orange peels

This research aims to optimize the environmentally sustainable and economically feasible process for soluble dietary fiber concentrate (SDFC) production from waste citrus peel by different physical methods, including micronization, autoclave, autoclave followed by micronization, extrusion, and ultrasonication. The study is mainly divided into two sections. The first section deals with a detailed life cycle assessment (LCA) of the size 40 kg SDFC/batch process and investigates the influence of various renewable energy sources, including biomass, solar, and wind electricity, on the environmental impact and compares it with mixed grid electricity. It was observed that the use of solar and wind electricity reduces CO₂ emissions by 95.93 % and 99.07 %, respectively. In the second section, technoeconomic analysis (TEA) was performed of all processes for the same capability as LCA, with sensitivity analysis to investigate the influence of batch size by varying batch size from 10 kg to 250 kg to investigate the impact of scale-up from pilot to industrial scale. Moreover, study the impact of energy sources from mixed-grid to renewable energy on total plant economics. TEA shows that extrusion performs the best among all, with an internal rate of return of 43.77 %. Whereas by using solar-based electricity, the overall utility cost is reduced by 58 % compared to the mix grid electricity.

Incorporating dietary fiber from fruit and vegetable waste in meat products: a systematic approach for sustainable meat processing and improving the functional, nutritional and health attributes

Background

Every year, the food business produces a sizeable amount of waste, including the portions of fruits and vegetables that are inedible, and those that have reached a stage where they are no longer suitable for human consumption. These by-products comprise of components such as natural antioxidants (polyphenols, carotenoid etc.), dietary fiber, and other trace elements, which can provide functionality to food. Due to changing lifestyles, there is an increased demand for ready-to-eat products like sausages, salami, and meat patties. In this line, meat products like buffalo meat sausages and patties are also gaining the interest of consumers because of their rich taste. Meat, however, has a high percentage of fat and is totally deprived of dietary fiber, which poses severe health problems like cardiovascular (CV) and gastrointestinal diseases. The health-conscious consumer is becoming increasingly aware of the importance of balancing flavor and nutrition. Therefore, to overcome this problem, several fruit and vegetable wastes from their respective industries can be successfully incorporated into meat products that provide dietary fiber and play the role of natural antioxidants; this will slow down lipid oxidation and increase the shelf-life of meat products.

Methodology

Extensive literature searches have been performed using various scientific search engines. We collected relevant and informative data from subject-specific and recent literature on sustainable food processing of wasted food products. We also looked into the various applications of waste fruit and vegetable products, including cereals, when they are incorporated into meat and meat products. All relevant searches meeting the criteria were included in this review, and exclusion criteria were also set.

Results

The pomace and peels of fruits like grapes, pomegranates, cauliflower, sweet lime, and other citrus are some of the most commonly used fruit and vegetable by-products. These vegetable by-products help inhibit oxidation (of both lipids and proteins) and the growth of pathogenic and spoilage bacteria, all without altering the consumer's acceptability of the product on a sensory level. When included in meat products, these by-products have the potential to improve the overall product quality and lengthen its shelf-life under certain circumstances.

Conclusion

Cost-effective and easily accessible by-products from the fruit and vegetable processing industries can be used in meat products to enhance their quality features (physicochemical, microbial, sensory, and textural aspects) and health benefits. Additionally, this will provides environmental food sustainability by lowering waste disposal and improving the food's functional efficacy.

Anaerobic co-digestion of marine macroalgae waste and fruit waste: Effect of mixture ratio on biogas production

Marine macroalgae waste (MMW) was used at different mixing ratios with fruit waste (FW) to evaluate the potential of co-digestion in enhancing methane yield. The process was conducted at mesophilic conditions (37 °C) with a fixed amount of biomass (10 g, 3.5% TS) and inoculum (150 mL; digested sewage sludge) and using MMW:FW ratios from 40:60 to 70:30. The results showed inhibition of the process for most of the studied substrate ratios, and in the mono-digestion of both substrates, possibly due to the accumulation of volatile fatty acids. A maximum biogas yield of 295 mL/g VS with 72% of methane was however obtained for the 60MMW:40FW ratio, corresponding to an estimated maximum methane yield of 213 mL/g VS and around 46% of the theoretical maximum methane production (49% of organic matter removal). The results show that the co-digestion of MMW with FW enhances the methane yield of both independent substrates.

Valorization of fruit wastes for circular bioeconomy: Current advances, challenges, and opportunities

The demands for fruits and processed products have significantly increased following the surging human population growth and rising health awareness. However, an enormous amount of fruit waste is generated during their production life-cycle due to the inedible portion and perishable nature, which become a considerable burden to the environment. Embracing the concept of "circular economy", these fruit wastes represent sustainable and renewable resources and can be integrated into biorefinery platforms for valorization into a wide range of high-value products. To fully realize the potential of fruit waste in circular bioeconomy and provide insights on future commercial-scale applications, this review presented the recycling and utilization of fruit wastes in various applications, particularly focusing on pollutant bioremediation, renewable energy and biofuel production, biosynthesis of bioactive compounds and low-cost microbial growth media. Furthermore, the challenges of efficient valorization of fruit wastes were discussed and future prospects were proposed.

New insights into the interactions between Pb(II) and fruit waste biosorbent

Fruit waste is a sustainable biosorbent for heavy metal removal from wastewater. Elucidation of adsorption mechanism is imperative for the process control and development of effective adsorbents. In this study, watermelon rind (WR) exhibited selective and efficient Pb(II) adsorption with a maximum uptake of 230.5 mg/g at pH 5.0. The WR-packed bed column showed high Pb(II) uptake and robust durability over 10 adsorption-desorption cycles with long breakthrough time of 8-13 h (89-144 bed volume), and 95% of sequestered Pb(II) was rapidly desorbed in 1-2 h by 0.05 M HCl. Spectroscopic characterization by FTIR and XPS identified hydroxyl, carboxyl, amine, and ether groups as the binding sites for Pb(II) via the binding force of complexation. Physicochemical analysis showed that ion exchange with Mg²⁺ and Ca²⁺ accounted for 19% of Pb(II) adsorption by WR; electrostatic attraction and microprecipitation jointly contributed. Quantum chemistry simulation verified the interactions between Pb(II) and binding sites and revealed carboxyl was the preferential functional group. The findings corroborate the applicability of WR in scale-up Pb(II) removal/recovery from wastewater and elaborate the mechanisms of Pb(II) adsorption by the WR biosorbent. This also provides insights into the behavior of heavy metals in other liquid/solid interfaces.

Bottom ash from smouldered digestate and coconut coir as an alkalinity supplement for the anaerobic digestion of fruit waste

Anaerobic digestion (AD) of readily hydrolysed substrates such as fruit waste requires the addition of a pH buffering agent. This study evaluated the use of bottom ash from the combustion of spent coconut coir and the digestate produced from rejected berry fruit and plant waste as a buffering agent. The performance of the ash was compared with using an equivalent amount of NaHCO₃ as a buffering agent. Digestions of berry fruit waste were performed in 160 mL serum vials using anaerobic wastewater sludge as an inoculum. The methane yield at the optimum levels of buffering with NaHCO₃ as the buffering agent was 233 ± 12 NmL CH₄/g VS. The methane yield at an equivalent addition of alkalinity as ash was significantly less, (124 ± 3 NmL CH₄/g VS), but still beneficial compared to the methane yield obtained from experiments with no added alkalinity (40 ± 1 NmL CH₄/g VS). Further dosages of ash in systems containing optimal level of NaHCO₃ buffer also revealed a decrease in the methane yield proportionally to the added ash concentration, which is suggested to be caused by soluble concentrations of Fe in the ash supplemented systems that are higher than reported inhibitory levels.

Enrichment of hydrogen production from fruit waste biomass using ozonation assisted with citric acid

In this study, the impact of ozonation abetted with the citric acid pretreatment (OZCAP) method on fruit waste was investigated for ameliorating hydrogen production. Initially, the ozonation pretreatment (OZP) method was performed by varying ozone (O₃) dosage and disintegration time. At optimized conditions (O₃ dosage (0.04 g/g suspended solid; SS) and disintegration time (40 minutes)), 17.6% of liquefied organics emancipate rate (LER) and 13.5% of SS reduction were perceived. Further augmenting LER of fruit waste, OZCAP method was proceeded by varying citric acid dosage and disintegration time at an optimized OZP dosage (0.04 g/g SS). A higher LER (24.4%) and SS reduction (19%) were described at an optimal citric acid dosage (0.03 g/g SS) and disintegration time (20 minutes). Then, the hydrogen production potential of OZCAP, OZP and raw fruit waste were evaluated in which OZCAP method exhibited a higher cumulative hydrogen production (30 mL/g volatile solids). Energy valuation reveals that OZCAP method exhibited a net energy of 3.7 kWh/kg of fruit waste.

Production of volatile fatty acid from fruit waste by anaerobic digestion at high organic loading rates: Performance and microbial community characteristics

This study examined the performance and microbial community dynamics of an anaerobic volatile fatty acid (VFA) production reactor for treating fruit waste by stepwise increasing organic loading rates (OLRs) from 8 to 24 g volatile total solids (VTS)/(L·d). Results showed that higher VFA concentrations of 52.25-61.90 g chemical oxygen demand (COD)/L can be maintained at each OLR, thereby resulting to a production of 0.70-0.76 g chemical oxygen demand (COD)_VFA/g VTS. Notably, an increase in OLR from 8 to 14 g VTS/(L·d) was beneficial for achieving higher VFA concentrations and yields. Moreover, an increase in OLR affected the VFA distribution significantly; acetate and butyrate became dominant in the fermentation liquid at OLRs ≥ 14 g VTS/(L·d). Microbial community dynamics analysis revealed that phyla Firmicutes and Actinobacteriota were predominant at each OLR, and the genera Lactobacillus, Clostridium_sensu_stricto_12, and Caproiciproducens were closely related to anaerobic VFA production.

Overview of pretreatment technologies on vegetable, fruit and flower market wastes disintegration and bioenergy potential: Indian scenario

Disposal of segregated organic fractions of centralized wholesale market wastes (i.e. vegetable, fruit and flower markets waste) in dumpsites/landfills are not only a serious issue but also underutilizes the huge potency of these organic wastes. Anaerobic digestion (AD) is a promising technology for converting organic wastes into methane, as a carbon-neutral alternative to conventional fuels. The major challenges related to the AD process are poor biodegradation of wastes and buffering capacity within the anaerobic digester that lowers the biogas yield. To accelerate biodegradation and to enhance the process efficacy of anaerobic digestion, several pretreatment technologies (mechanical, thermal, biological, chemical and combined pre-treatments) for organic wastes prior to the AD process were developed. This review article presents a comprehensive analysis of research updates in pretreatment techniques for vegetable, fruit and flower markets wastes for enhancing biogas yields during the AD process. The technological aspects of the pretreatment process are described and their efficiency comparison with the resultant process yields and environmental benefits are also discussed. The challenges and technical issues associated with each pretreatment and future research directions for overcoming the field implementation issues are also proposed.

Sludge retention time impacts on polyhydroxyalkanoate productivity in uncoupled storage/growth processes

The process involving mixed microbial cultures (MMCs) and waste-based substrates emerged as an alternative solution to reduce the market price of polyhydroxyalkanoates (PHAs). The selection of an efficient MMC that displays a significant PHA accumulation potential and a high growth rate is considered a key factor for the MMC PHA production feasibility. This study used a pilot plant to investigate the dynamics of growth vs storage in a mixed culture fed with fermented fruit waste under uncoupled carbon and nitrogen feeding. Varying sludge retention times (SRTs) (2 and 4 d) and organic loading rates (OLRs) (from 2.6 to 14.5 gCOD.L^-1.d^-1) were imposed for this purpose. Results showed that, regardless of the OLR imposed, cultures selected at lower SRT grew faster and more efficiently using stored PHA. However, they had inferior specific storage rates and accumulation capacity, resulting in lower PHA productivity. Additionally, the polymer storage yield was independent of the SRT, and was directly linked with the abundance of putative PHA-storers in the MMC. The high PHA productivity (4.6 ± 0.3 g.L^-1.d^-1) obtained for the culture selected at 4 d of SRT was 80% above that obtained for the lower SRT tested, underlining the importance of achieving a good balance between culture growth and accumulation capacity to increase the viability of the PHA-producing process from wastes.

Technological advances for improving fungal cellulase production from fruit wastes for bioenergy application: A review

Fruit wastes can be imperative to elevate economical biomass to biofuels production process at pilot scale. Because of the renewable features, huge availability, having low lignin content organic nature and low cost; these wastes can be of much interest for cellulase enzyme production. This review provides recent advances on the fungal cellulase production using fruit wastes as a potential substrate. Also, the availability of fruit wastes, generation and processing data and their potential applications for cellulase enzyme production have been discussed. Several aspects, including cellulase and its function, solid-state fermentation, process parameters, microbial source, and the application of enzyme in biofuels industries have also been discussed. Further, emphasis has been made on various bottlenecks and feasible approaches such as use of nanomaterials, co-culture, molecular techniques, genetic engineering, and cost economy analysis to develop a low-cost based comprehensive technology for viable production of cellulase and its application in biofuels production technology.

Harnessing fruit waste for poly-3-hydroxybutyrate production: A review

Poly-3-hydroxybutyrate is a biopolymer which has shown tremendous potential for replacing conventional petroleum-based plastics for plummeting the plastic pollution problem. However, the production cost of PHB is high which makes it less attractive for commercial use. To tackle this challenge, various researchers suggest the search for low-cost substrates and energy efficient technologies for PHB production. In this regard, the waste generated from fruit processing industries or fruit wastes could be pre-processed and fermented for effectively generating PHB. Therefore, the aim of this review was to focus on the methods of fruit waste pre-processing and the effect of fermentation variables on PHB production using fruit waste as a substrate. The relevant research findings on the use of different microorganisms, PHB production conditions and fruit waste-based substrates are also covered. Analysis of various studies revealed that pineapple and mixed fruit waste are effective for PHB production.

Facile green synthesis of silver nanoparticles using Mangifera indica seed aqueous extract and its antimicrobial, antioxidant and cytotoxic potential (3-in-1 system)

A novel approach for the utilisation of fruit waste is attempted in the present investigation. Mangifera indica seed aqueous extract was utilised for green synthesis of silver nanoparticles (AgNPs). The phytoconstituents in the seed acted as reducing and stabilising agent for AgNP formation. UV-Vis, Zeta potential, FT-IR, XRD, TEM, SAED, EDX analysis were used to characterise the green synthesised AgNPs. UV-vis spectra showed characteristic spectra at 450 nm; XRD and SAED confirmed the crystalline nature while TEM revealed the shape to be round and average size was 26.85 nm. FT-IR revealed functional groups like alcohol or phenols, carboxylic acids, ketones, amines, aromatic amines, aliphatic amines, alkyl halides and alkynes which were responsible for AgNP formation. The nanoparticles showed more antibacterial activity than antifungal activity and antibacterial activity towards Gram-negative bacteria was more than Gram-positive bacteria. Dose dependent antioxidant activity (DPPH, SO and ABTS) and dose dependent cytotoxic effect against HeLa, MCF-7 and normal fibroblast cell lines was envisaged. The green synthesised AgNPs exhibited three different bioactivities (3-in-1 system) i.e. dose dependent antimicrobial, antioxidant and cytotoxic activity. Fruit waste can be successfully utilised for silver nanoparticles formation which can be therapeutically useful and effective.[Figure: see text]HighlightsSilver nanoparticles were synthesised from M. indica fruit waste i.e. seedCharacterisation by spectroscopic techniques: UV-Vis, Zeta, FTIR, XRD, SAED, EDX and TEM analysis.Silver nanoparticles were 26.85 nm in size and round in shapeAntimicrobial activity against 14 microorganismsAntioxidant activity in terms of DPPH, SO and ABTSCytotoxic activity against HeLa, MCF-7 and Fibroblast normal cell lines.

Utilization of over-ripened fruit (waste fruit) for the eco-friendly production of ethanol

This research was carried out to produce ethanol for use as a sanitizer in today’s COVID-19 pandemic situation, via cost-effective and eco-friendly techniques. The waste of seasonal fruit, i.e. apple, grape and Indian blueberry, was used in the study. Saccharomyces cerevisiae (baker’s yeast) was used with KMnO₄ (5%), sucrose (47 g) and urea (1.5 g) for the fermentation process. All the selected overripe fruits were analyzed for variations in parameters including specific gravity, pH, temperature and concentration during complete fermentation for ethanol production. After complete fermentation, it was clear that the use of Indian blueberry at a temperature of 33 °C, specific gravity of 0.875 and pH value of 5.2 yielded the highest ethanol concentration of 6.5%. The concentration of ethanol obtained from grape samples was 5.23% at 30 °C with specific gravity of 0.839 and pH 4.3. Lastly, the ethanol concentration obtained from apple waste was about 4.52% at 32 °C with specific gravity of 0.880 and pH of 4.7 pH. The FTIR curve of each sample shows an absorbance peak in a wave number range of 3000 cm⁻¹ to 3500 cm⁻¹, which indicates the absence of alcohol in the samples after fermentation.

Utilization of seawater and wastewater from shrimp production in the fermentation of papaya residues to ethanol

Seawater (SW) and wastewater from shrimp production (WSP) were used as a solvent for the fermentation of papaya residues (Carica papaya) by Wickerhamomyces sp. UFFS-CE-3.1.2 and Saccharomyces cerevisiae CAT-1. For comparative purposes and evaluation of the effect of salinity, ultrapure water (UW) was used as control. Fermentative parameters were evaluated in Plackett-Burman planning to assess ethanol production's significant variables. Urea supplementation was the only variable not significant for the proposed process, suggesting that papaya residues contain all the nutrients needed for fermentation. The experiments conducted with the different water sources resulted in similar concentrations of ethanol. Maximum ethanol concentration was obtained after nine h of fermentation usingWickerhamomycessp. UFFS-CE-3.1.2 (27.31 ± 1.40 g L^-1) and 12 h using S. cerevisiaeCAT-1 (24.53 ± 0.68 g L^-1). This study demonstrated that SW and WSP could replace freshwater without affecting ethanol production. Papaya residues from the fruit and vegetable sectors can be considered a promising substrate source for ethanol production.

As(III) and As(V) removal by using iron impregnated biosorbents derived from waste biomass of Citrus limmeta (peel and pulp) from the aqueous solution and ground water

Now a day's biosorbents with magnetic properties have been applied for water and wastewater treatment process, because of its magnetic nature it can be easily separated and can be reused more than one time. In the present study, two magnetic biosorbents were synthesized from waste biomass of Citrus limetta (peel and pulp) at 500 °C temperature represented as PAC-500 and PPAC-500. These biosorbents were effectively used for the removal of As(III) and As(V) from an aqueous solution and groundwater samples. The prepared biosorbents were characterized by using Brunauer Emmett Teller (BET), Zeta potential, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Disperssive X-ray (EDS), X-ray Diffraction (XRD) and Particle Size Analyzer (PSA). Isotherms, kinetics and thermodynamics were also applied to the obtained experimental data. The regeneration study revealed that the biosorbent can be recycled up to four cycles. The adsorbent capacity of PAC-500 and PPAC-500 for the sorption of As(III) was 714.28 μg/g and 526.31 μg/g, respectively, whereas the q_max value for As(V) sorption was 2000 μg/g for both the biosorbents (PAC-500 and PPAC-500). The effect of competitive ions was also studied that shows that the presence of H₂PO₄^- and CO₃² have negative effects on the sorption of As(III) and As(V). Arsenic is very toxic and it is a more important subject for consideration, therefore it is necessary to develop a low cost material that is very efficient in removing As from ground water contaminated with As water.

Bacillus sp. isolated from banana waste and analysis of metabolic pathways in acidogenic systems in hydrogen production

The autochthonous bacterial strain was isolated from banana waste (BW) for hydrogen production and organic acids from different pure substrates and BW. The potential production of H₂ and metabolic pathways were analyzed at pH 7.0 at 37 °C. Facultative anaerobic bacterium similar to Bacillus sp. was identified, with generation time (Tg) and growth rate (μ) of 0.43 h and 1.60 h^-1, respectively, from glucose. The hydrogen production (P) using pure substrates was observed between 10.81 mmol.L^-1 and 17.75 mmol.L^-1 from xylose and maltose, respectively. The biggest and smallest hydrogen P of 18.77 mmol.L^-1 and 1.72 mmol.L^-1, were obtained with 3.5 and 0.5 g.L^-1 of cellobiose, respectively. The highest hydrogen yield (126.93 mL.g^-1_{carbohydrates added}) was obtained with 2 g.L^-1 cellobiose. In the assay using banana waste (5 g.L^-1) the maximum P and yield (YH₂) of 31.7 mmol.L^-1 and 94.66 mL H₂ g^-1_{carbohydrates added}, was obtained respectively. The main metabolic pathway of hydrogen production by Bacillus sp. RM1 from banana waste was acetic-butyric acid of 487.69 g.L^-1 and 535.88 g.L^-1, respectively. The accessibility of various carbon sources by Bacillus sp. RM1 in fermentation can benefit the hydrogen production from complex organic substrates in the bioaugmentation process.

Fruit waste management by pigment production and utilization of residual as bioadsorbent

Dry powder of fruit wastes including pomegranate, grapes, lime, apple, and papaya was used to examine their pigment extraction capability. Solvent combination of hexane and acetone (1:1) produced the maximum extraction for lime waste with a yield of 1.65%. Gas Chromatography and Mass Spectrometry analysis of the crude pigment of lime exhibited the abundance of compounds like chlorogenic acid, caffeic acid, and coumaric acid. Three major bands were obtained in Thin Layer Chromatography. Column Chromatographic purification using ethyl acetate and hexane mixture as eluting phase showed a retention factor of 0.62 for the major band. Nuclear Magnetic Resonance revealed the final structure of the compound as chlorogenic acid. Slight inhibition was exhibited by the compound against Escherichia coli. Adsorption of arsenate by residual fruit waste revealed the highest adsorption in grapes with 92% efficiency. This study enlightens an alternative approach of fruit waste management with the production of value-added products and its utilization of residue as bioadsorbent.

Enhancing methane production using anaerobic co-digestion of waste activated sludge with combined fruit waste and cheese whey

BACKGROUND

Recently, it has been indicated that anaerobic co-digestion of waste activated sludge with other waste streams at wastewater treatment plants is a promising strategy for enhancing methane production and materials recovery. The enhanced methane production can be used as a renewable source of energy in wastewater treatment plants. It can also reduce the amount of greenhouse gas emission in landfilling of the waste streams.

RESULTS

According to the results obtained in this study, anaerobic co-digestion of waste activated sludge with mixed fruit waste and cheese whey improves methane production and the quality of digested sludge in comparison to the anaerobic digestion of waste activated sludge individually. It was indicated that carbon/nitrogen ratio (C/N) in the mixture of waste activated sludge, fruit waste and cheese whey improved considerably, leading to better anaerobic organisms' activity during digestion. With assessing the activity of protease and cellulase, as the main enzymes hydrolyzing organic matter in anaerobic digestion, it was indicated that co-digestion of waste activated sludge with mixed fruit waste and cheese whey enhances the activity of these enzymes by 22 and 9% respectively. At the end of digestion, the amount of cumulative methane production significantly increased by 31% in the reactor with 85% waste activated sludge and 15% mixed fruit waste and cheese whey, compared to the reactor with 100% waste activated sludge. In addition, chemical oxygen demand (COD) and volatile solid (VS) in digested sludge was improved respectively by 9 and 7% when mixed fruit waste and cheese whey was used.

CONCLUSIONS

This study revealed that mixed fruit waste and cheese whey is potentially applicable to anaerobic digestion of waste activated sludge, as fruit waste and cheese whey have high C/N ratio that enhance low C/N in waste activated sludge and provide a better diet for anaerobic organisms. This is of significant importance because not only could higher amount of renewable energy be generated from the enhanced methane production in wastewater treatment plants, but also capital costs of the companies whose waste streams are being transported to wastewater treatments plants could be reduced considerably.

Rambutan fruit peel powder and dietary protein level influencing on fermentation characteristics, nutrient digestibility, ruminal microorganisms and gas production using in vitro fermentation techniques

The objective of this study was to evaluate the effect of rambutan (Nephelium lappaceum) fruit peel powder (RP) on fermentation characteristics, rumen microorganisms, and in vitro gas production. Three levels of crude protein (CP) in the concentrate (14%, 16%, and 18% CP) and supplementation of rambutan peel powder (0, 2, 4, and 6% of the total dietary substrate) were designed for treatments according to 3 × 4 factorial arrangement in a completely randomized design (CRD). The rumen fluid samples were collected from two-fistulated dairy bulls which had been fed on rice straw with concentrate to adjust the rumen environment. The ratio of roughage (R) and concentrate (C) at 60:40 was used, and all ingredients were added according to the mentioned ratio, respectively. Under this study, supplementation of CP at different levels in the concentrate diet significantly altered (P < 0.05) rumen NH₃-N at 6 and after 12 h of incubation, whereas the rumen pH was not significantly changed with CP and RP supplementation levels at any times of incubation. The rumen pH was declined at 18% CP at 6 h of incubation time, as compared to 14 and 16% CP with 0% RP supplementation. The CP and RP supplementation could enhance and maintain the rumen pH during incubation to the optimum condition. The RP supplementation significantly doubled bacterial population while reduced protozoal population; however, fungal zoospores were not altered with CP and RP supplementation. The ruminal propionate (C₃) production was remarkably higher (P < 0.05) by the RP and CP supplementation. The ratio of acetate to propionate (C₂:C₃) was decreased (P < 0.05) with RP supplementation. Meanwhile, rumen methane (CH₄) production was significantly reduced by the RP supplementation. In addition, high level of RP supplementation (6% of total substrate) also significantly decreased the cumulative gas production and the in vitro true digestibility (%IVTDMD). Level of CP had no effect on rumen fermentation while interactive effects of CP level and RP supplementation were not found. This current study indicated that RP supplementation could suppress protozoal population, mitigate methane production, and improve rumen fermentation.

Performance of semi-continuous anaerobic co-digestion of poultry manure with fruit and vegetable waste and analysis of digestate quality: A bench scale study

Poultry manure (PM) can contain ammonium and ammonia nitrogen, which may inhibit the anaerobic process. The aim of this work was to evaluate the performance of anaerobic digestion of PM co-digested with fruit and vegetable waste. Two semi-continuous bench scale (19L) stirred tank reactors were used. The operating conditions were: 34.5 °C, 2 gVS/L.d (organic load rate), 28 d of hydraulic retention time and 100 revolutions per m (1 h × 3 times by day) for the agitation. The reactors were fed PM and a mixture of PM and fruit and vegetable waste (FVW) at equal proportions (based on wet weight). The performance of the anaerobic process was assessed through biogas and methane yields, reduction of organic matter, release of nitrogen compounds and the monitoring of stability indicators (pH, volatile fatty acids (VFA), total (TA) and partial (PA) alkalinity). Moreover, the digestate quality was evaluated to determine potential risk and benefits from its application as biofertilizer. Toxicity was assessed using Daphnia magna immobilization tests. Results showed that biogas and methane yields from PM-FVW were 31% and 32% higher than PM alone, respectively. Values of organic matter, pH, alpha (PA/TA) and VFA revealed that stability was approached in PM and PM-FVW. The co-digestion of PM with FVW led to the highest methane and biogas yields, lower FAN and TAN concentrations, and a better digestate quality compared to mono-digestion of this manure.

Experimental and feasibility assessment of biogas production by anaerobic digestion of fruit and vegetable waste from Joburg Market

Substrate-induced instability of anaerobic digestion from fruit and vegetable waste (FVW) results in low biogas yield. In this study, substrate management through fruit to vegetable mix ratio in a two-stage semi-continuous digester was investigated as a pathway for optimality of yield. The experiment conducted over 105 days with 62.52 kg of FVWs sourced from Joburg Market, South Africa showed that a stable process was achieved at a fruit to vegetable waste mix ratio of 2.2:2.8. At this ratio, optimal organic loading rate ranged between 2.68 and 2.97 kg VS/m³-d which resulted in a specific biogas yield of 0.87 Nm³/kg VS with 57.58% methane on average. The results of the experimental study were used as a feasibility assessment for a full-scale 45 tonnes/d plant for Joburg Market considering three energy pathways. The plant will produce 1,605,455 Nm³/y of biogas with the potential for offsetting 15.2% of the Joburg Market energy demand. Conversion of all biogas to biomethane was the most economically attractive energy pathway with a net present value of $2,428,021, an internal rate of return of 16.90% and a simple payback period of 6.17 years. This route avoided the greenhouse gas emission of 12,393 tonnes CO₂, eq. The study shows that the anaerobic digestion of FVWs as sole substrate is possible with financial and environmental attractiveness.

Processing of wet Kinnow mandarin (Citrus reticulata) fruit waste into novel Brønsted acidic ionic liquids and their application in hydrolysis of sucrose

In citrus processing industries, where up to 60% of the whole fruit is discarded, generates citrus waste (peel, seeds, membrane, and pulp) on a massive scale. The waste does not currently have high-value applications, instead the majority is disposed of or pelletized for animal feed. Therefore, a concise and efficacious protocol for processing of Kinnow mandarin (Citrus reticulata) fruit waste to numerous novel Brønsted acidic ionic liquids (3a-k) have been developed. BAILs were characterized using spectroscopic techniques (FT-IR and NMR). Water immiscibility of ILs 3a, 3g and 3h, a property never observed with sulfonic acid ILs, allowed the catalytic application of BAIL 3a in hydrolysis of sucrose/table sugar, giving a mixture of d-glucose and d-fructose in excellent yields. The ionic liquid could be recycled for >3 times without significant loss of activity.

The seasonal evolution of fruit, vegetable and yard wastes by mono, co and tri-digestion at Hyderabad, Sindh Pakistan

The contribution of biowastes in municipal solid waste (MSW) is increasing day by day and being dumped in open atmosphere along with other wastes in every city of Pakistan. This study was formulated to evaluate the feasibility of biowastes such as fruit, vegetable and yard wastes of different seasons individual and mixing at different ratios to optimize methane production at Hyderabad Sindh, Pakistan. Batch digestion of selected samples was conducted for 40 days under mesophilic condition. Methane yield of individual fruit, vegetable and yard wastes (FrVYW) of summer and winter season was obtained in the range of 0.36-0.40 L/g VS and 0.39-0.44 L/g VS added respectively. The results of co-digestion of FrVYW of summer and winter season were observed in the range of 0.42-0.45 L/g VS added and 0.46 to 0.54 L/g VS added respectively. The results of tri-digestion of FrVYW of summer and winter season were achieved in the range of 0.46-0.53 L/g VS added and 0.56-0.62 L/g VS added respectively. Findings of study showed that methane production potential of tri-digestions were highest than all of others and that of co-digestion were higher than mono-digestion of FrVYW. Overall results of study concluded that tri-digestion of FrVYW at the equal blending ratio reported highest methane potential. Therefore, the study recommended that tri-digestion of FrVYW at equal mixing ratio is an optimal ratio for anaerobic digestion process to yield maximum methane production from FrVYW.

Effects of size and thermophilic pre-hydrolysis of banana peel during anaerobic digestion, and biomethanation potential of key tropical fruit wastes

Methane production potential of tropical fruit wastes, namely lady-finger banana peel, rambutan waste and longan waste were compared using BMP assay and stoichiometric modified Buswell and Mueller equation. Methane yields based on volatile solid (VS) were in the order of ground banana peel, chopped banana peel, chopped longan waste, and chopped rambutan waste (330.6, 268.3, 234.6 and 193.2 mLCH₄/gVS) that corresponded to their calculated biodegradability. In continuous operations of banana peel digestion at feed concentrations based on total solid (TS) 1-2%, mesophilic single stage digester run at 20-day hydraulic retention time (20-day HRT) failed at 2%TS, but successfully recovered at 1.5%TS. Pre-hydrolysis thermophilic reactor (4-d HRT) was placed as pre-treatment to mesophilic reactor (20-d HRT). Higher biogas (with an evolution of H₂) and energy yields were obtained and greater system stability was achieved over the single stage digestion, particularly at higher solid feedstock. The best performance of two stage digestion was 68.5% VS destruction and energy yield of 2510.9kJ/kgVS added at a feed concentration of 2%TS.

Current technologies and new insights for the recovery of high valuable compounds from fruits by-products

The recovery of high valuable compounds from food waste is becoming a tighten issue in food processing. The large amount of non-edible residues produced by food industries causes pollution, difficulties in the management, and economic loss. The waste produced during the transformation of fruits includes a huge amount of materials such as peels, seeds, and bagasse, whose disposal usually represents a problem. Research over the past 20 years revealed that many food wastes could serve as a source of potentially valuable bioactive compounds, such as antioxidants and vitamins with increasing scientific interest thanks to their beneficial effects on human health. The challenge for the recovery of these compounds is to find the most appropriate and environment friendly extraction technique able to achieve the maximum extraction yield without compromising the stability of the extracted products. Based on this scenario, the aim of the current review is twofold. The first is to give a brief overview of the most important bioactive compounds occurring in fruit wastes. The second is to describe the pro and cons of the most up-to-dated innovative and environment friendly extraction technologies that can be an alternative to the classical solvent extraction procedures for the recovery of valuable compounds from fruit processing. Furthermore, a final section will take into account published findings on the combination of some of these technologies to increase the extracts yields of bioactives.

Feasibility study of biodiesel production using lipids of Hermetia illucens larva fed with organic waste

Hermetia illucens larvae by nature are a decomposer which fed on organic wastes. This study explores the potential of producing biodiesel using lipids from H. illucens larvae. Three types of organic wastes (sewage sludge, fruit waste and palm decanter cake from oil palm mill) were selected based on considerable generation and disposal concern in the area of study as well as lack of investigations as feed for Hermetia illucens larvae in current literatures. Growth rate of the larvae was determined with studying the changes in the biomass per day. H. illucens larvae fed with fruit waste and palm decanter cake have shown growth rates of 0.52±0.02 and 0.23±0.09 g d(-1), respectively. No positive sign of growth were observed in the larvae fed with treated sewage sludge (-0.04±0.01 g d(-1)). Biodiesel as fatty acid methyl ester (FAME) was synthesized by transesterification of the larvae lipid using sulphuric acid as catalyst in methanol. FAME produced was ascertained using ATR-FTIR spectroscopy and GC-MS. The main compositions of fatty acid were found to be C12:0, C16:0 and C18:1n9c. Fatty acid composition of C12:0 fed with fruit waste, sewage sludge and palm decanter was found to be most abundant in the larvae lipid. The amount of C12:0 obtained was 76.13%, 58.31% and 48.06%, respectively. In addition, fatty acid of C16:0 was attained at 16.48% and 25.48% fed with sewage sludge and palm decanter, respectively. Based on the findings, FAME derived from larvae lipids is feasible to be used for biodiesel production.

Utilization of plant-based natural coagulants as future alternatives towards sustainable water clarification

Rapid industrial developments coupled with surging population growth have complicated issues dealing with water scarcity as the quest for clean and sanitized water intensifies globally. Existing fresh water supplies could be contaminated with organic, inorganic and biological matters that have potential harm to the society. Turbidity in general is a measure of water cloudiness induced by such colloidal and suspended matters and is also one of the major criteria in raw water monitoring to meet the stipulated water quality guidelines. Turbidity reduction is often accomplished using chemical coagulants such as alum. The use of alum is widely associated with potential development of health issues and generation of voluminous sludge. Natural coagulants that are available in abundance can certainly be considered in addressing the drawbacks associated with the use of chemical coagulants. Twenty one types of plant-based natural coagulants categorized as fruit waste and others are identified and presented collectively with their research summary in this review. The barriers and prospects of commercialization of natural coagulants in near future are also discussed.

Anaerobic co-digestion of dairy cattle manure and pear waste

Anaerobic co-digestion of pre-treated dairy cattle manure (LCM) with pear waste after a storage period (PLF) was tested at four inclusion levels: 0%, 25%, 75% and 100%. Inclusion levels consisted in the replacement of the volatile solids (VS) from the LCM with the VS from PLF keeping the organic loading rate around 1.1 ± 0.4 g SVL(-1)d(-1). The introduction of the co-substrate clearly enhanced methane production rate (MPR) in comparison to single substrate (phase I) as phases II and III, respectively, achieving values 1.3 and 2.8 times higher than phase I. The overall performance was optimized for the mixture 25:75 (LCM:PLF; v:v). Moreover, storage of pear waste did not compromise its use in AD. This fact is important once it can improve waste management from pear production through its valorisation as co-substrate in AD process.

Inhibitory effects of fruit flavors on methane production during anaerobic digestion

In order to improve biogas production from fruit wastes, the inhibitory effects of fruit flavors on anaerobic digestion were investigated. Batch anaerobic digestion was performed for 30 days using synthetic medium and thermophilic sludge. Three groups of flavor compounds i.e. aldehydes (hexanal, nonanal, and E-2-hexenal), terpenes (car-3-ene, α-pinene, and myrcene), and alcohol (octanol) at concentration of 0.005%, 0.05%, and 0.5% were examined. All the flavor compounds showed inhibitory effect on methane production. The highest methane reduction was obtained at addition of 0.5% of flavor compounds. For terpenoids, the presence of 0.5% of car-3-ene, myrcene, and α-pinene reduced 95%, 75%, and 77% of methane production, respectively. For aldehydes, addition of 0.5% concentration resulted in more than 99% methane reduction for hexanal and E-2-hexenal, and 84% methane reduction for nonanal. For alcohol, the presence of 0.5% octanol decreased 99% methane production.