Polysaccharides from fruit and vegetable wastes and their food applications: A review.

Fruit and vegetables are a great source of nutrients and have numerous health benefits. The fruit and vegetable industry produces enormous amounts of waste such as peels, seeds, and stems. The amount of this waste production has increased, causing economic and environmental problems. Fruit and vegetable wastes (FVWs) have the potential to be recovered and used to produce high-value goods. Furthermore, FVWs have a large variety and quantity of polysaccharides, which makes them interesting to study for potential industrial use. Currently, the investigations on extracting polysaccharides from FVWs and examining how they affect human health are increasing. The present review focuses on polysaccharides from FVWs such as starch, pectin, cellulose, and inulin, and their various biological activities such as anti-inflammatory, anti-tumor, anti-diabetic, antioxidant, and antimicrobial. Additionally, applications as packaging material, gelling agent, emulsifier, prebiotic, and fat replacer of polysaccharides from FVWs in the food industry have been viewed in detail. As a result, FVWs can be reused as the source of polysaccharides, reducing environmental pollution and enabling sustainable green development. Further investigation of the biological activities of polysaccharides from FVWs on human health is of great importance for using these polysaccharides in food applications.

Nutritive evaluation of dried cabbage (Brassica oleracea var. capitata) waste meal as feed for grower-finisher pigs.

This research investigated the nutritive value of dried cabbage waste meal (CWM) as feed for grower-finisher pigs. One hundred crossbred (Large white X Landrace; 86.10 ± 0.15 kg BW) clinically certified grower-finisher pigs of equal sexes were randomly allocated to five dietary treatments with five replicates per treatment in a completely randomized design. The control diet (T0 Diet) contained 1000 g kg-1DM concentrate without CWM, while diets T50, T100, T150 and T200 had 50, 100, 150 and 200 g kg-1 DM levels of inclusion of CWM, respectively, replacing parts of the total mixed ration (TMR). Data were collected on growth performance, carcass indices, blood biochemical profiles, and economics characteristics of pigs. The study lasted for 8 weeks. Feed and water were available ad libitum. Feed intake (2336.74-2651.01 g/d) increased (p < 0.05) while weight gain (913.04-877.53 g/d) and feed conversion ratio (2.56-3.02) were better (p < 0.05) among pigs fed T0, T50 and T100 diets. Carcass parameters followed the same trend as growth indices (p < 0.05). Red blood cell counts (6.04-8.57 × 1012/L), haemoglobin (15.10-18.35 g/dl) and neutrophils (21.28-25.88%) concentrations increased (p < 0.05) among pigs fed cabbage waste meal. Aspartate aminotransferase concentrations (33.25-40.23 U/L) increased (p < 0.05) significantly among pigs fed T100, T150 and T200 diets. Total cost of feeding (61.19-56.27 $) reduced (p < 0.05) with similar gross benefits (48.97-52.30 $) across the treatment groups. The results suggest that up to 100 g kg-1 CWM could be incorporated into pig diets to improve their growth performance and support profitable pig production.

Dried cabbage (Brassica oleracea var. capitata) waste meal decreases blood cholesterol but does not alter growth performance, and physiological indices of weaned pigs.

The study investigated the potentials of dried cabbage waste meal (DCWM) on growth performance, blood biochemical characteristics, physiological indices, and economics of production of weaned pigs. Ninety crossbred (Large white X Landrace; 8.01 ± 0.18 kg body weight) clinically certified weaned pigs of equal sexes were randomly allocated to five dietary treatments containing DCWM. Each treatment consisted of 18 pigs replicated thrice in a completely randomized design. Diet 1 (control diet) contained no DCWM whereas diets 2, 3, 4 and 5 had 50, 100, 150 and 200 g/kg levels of inclusion of DCWM, respectively, replacing parts of the feed. The study lasted for 8-weeks. Feed and water were available ad-libitum. Average daily feed intake (715.76-780.03 g/d) increased (p < 0.05) while average daily weight (294.17-301.74 g/d) and feed conversion ratio (2.39-2.65) were similar (p > 0.05). White blood cell (12.11-14.62 × 109/L), lymphocytes (62.93-70.30%), Uric acid (7.74-9.99 mmol/L), HDL (0.89-1.27 mmol/L) and K (130.90-145.72 mmol/L) concentrations increased (p < 0.05) whereas cholesterol (2.30-5.06 mmol/L) and triglyceride (0.33-0.87 mmol/L) concentrations decreased (p < 0.05) in response to increased DCWM in the diets. Total cost of feeding ($17.96-20.89) reduced (p < 0.05) while gross benefits ($48.97-52.30) were significantly better (p < 0.05) for pigs fed 100, 150 and 200 g/kg DCWM compared to those fed 0 and 50 g/kg diets. DCWM in pig diets up to 200 g/kg had positive influence on blood cholesterol and economics of production.

Physicochemical, Technological and Functional Properties of Upcycled Vegetable Waste Ingredients as Affected by Processing and Storage.

Vegetable wastes are generated during harvesting, processing, and distribution, which implies a wastage of nutrients and evidence inefficiencies in present food systems. Vegetable residues are rich in bioactive compounds, for which their valorisation and reintroduction into the food chain are crucial towards circular economy and food systems sustainability. In this work, upcycled powdered ingredients were obtained from vegetables wastes (carrot, white cabbage, celery, and leek) through a disruption, dehydration and milling process. Disruption pre-treatment at different intensities was followed by freeze-drying or hot-air drying (60 and 70 °C), and final milling to produce fine powders. Powdered products were characterized in terms of physicochemical, antioxidant and technological properties (water and oil interaction), after processing and during four months of storage. Antioxidant properties were generally favoured by hot-air drying, particularly at 70 °C, attributed to new compounds formation combined to less exposure time to drying conditions. The powders showed good water interaction properties, especially freeze-dried ones. Storage had a negative impact on the quality of powders: moisture increased, antioxidant compounds generally diminished, and colour changes were evidenced. Upcycled vegetable waste powders are proposed as ingredients to fortify foods, both processing and storage conditions having an impact on their properties.

Current Technologies and Uses for Fruit and Vegetable Wastes in a Sustainable System: A Review.

The fruit and vegetable industry produces millions of tons of residues, which can cause large economic losses. Fruit and vegetable wastes and by-products contain a large number of bioactive substances with functional ingredients that have antioxidant, antibacterial, and other properties. Current technologies can utilize fruit and vegetable waste and by-products as ingredients, food bioactive compounds, and biofuels. Traditional and commercial utilization in the food industry includes such technologies as microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), ultrasonic-assisted extraction (UAE), and high hydrostatic pressure technique (HHP). Biorefinery methods for converting fruit and vegetable wastes into biofuels, such as anaerobic digestion (AD), fermentation, incineration, pyrolysis and gasification, and hydrothermal carbonization, are described. This study provides strategies for the processing of fruit and vegetable wastes using eco-friendly technologies and lays a foundation for the utilization of fruit and vegetable loss/waste and by-products in a sustainable system.

Towards food circular economy: hydrothermal treatment of mixed vegetable and fruit wastes to obtain fermentable sugars and bioactive compounds.

Due to processing activity, fruits and vegetables generate notable amounts of wastes at the processing, retail, and consumption level. Following the European goals for reducing food wastes and achieving a circular economy of resources, these biowastes should be valorized. In this work, hydrothermal hydrolysis at different conditions (temperatures, times, waste/water ratio, pH values) were tested to treat for first time; biowastes composed of mixed overripe fruits or vegetables to maximize the extraction of fermentable sugars that can be used as substrates in bioprocesses. Experimental data were fitted by a model based on irreversible first-order reactions, and kinetic constants were obtained. When hydrolysis of fruit wastes was carried out at 135 °C and pH 5 during 40 min, more than 40 g of reducing sugars per 100 g of waste (dry weight) could be obtained (represents an extraction of 97% of total carbohydrates). Concentrations of inhibitor compounds (HMF, furfural, acetic acid) in the hydrolysates were very low and, as example, a fermentation to obtain bioethanol was successfully carried out with an efficiency above 95%. Additionally, the production by hydrothermal treatment of bioactive compounds was investigated and the best results obtained were 92% DPPH inhibition and 12 mg GAE/g (dry weight) for antioxidant activity and phenolic compounds, respectively. These values are similar or even higher than those reported in literature using specific parts of fruits and vegetables.

Target and Enhance Ethanol and Butyrate Production from Anaerobic Fermentation via the pH and Organic Loading Rate Combined Strategy.

The large capacity production and low utilization rate increase the difficulty of fruit and vegetable wastes (FVW) treatment. Efficient and targeted recovery strategies can solve these problems. This study investigated and proposed combined strategies via pH and organic loading rate (OLR) to target and enhance ethanol- and butyrate-dominant acidogenic production in the FVW mixed culture fermentation. Under pH 4.0, OLR 18 gCOD/(L∙d), and mesophilic (35 °C), ethanol-dominant fermentation was formed. The long-term operation (168 days) showed that the highest ethanol yield was 0.33 g/gCOD which was greater than that in other studies. Also, the hydrolysis rate of ethanol-type fermentation reached 74.5%. Besides, butyrate-type fermentation was stable at yield 0.39 g/gCOD following conditions: pH 6.0, OLR 28 gCOD/(L∙d), and 35 °C, of which hydrolysis and acidogenic rate were 78.0% and 62.0%, respectively. The high relative abundance of Lactobacillus, Olsenella, and Bifidobacterium played positive role in achieving ethanol, butyrate, and lactate production among various metabolic pathways. The results revealed the pH value together with OLR was the valid parameter to affect product formation and composition during FVW fermentation.

Compositional components and methane production potential of typical vegetable wastes.

With the development of agriculture, a huge amount of vegetable waste (VW) is produced every year, posing a large considerable environmental problem that cannot be ignored. Anaerobic digestion (AD), as an eco-friendly, efficient, and sustainable biomass conversion technology, may be used to address the pollution caused by VW. The compositional components of various VWs are different, which will affect their biomethane potential and directly determine whether they are suitable substrates for AD. Thus, this study involved a systematic analysis of the composition and biomethane potential of 20 typical VWs. The results showed that the methane yields of the VWs were different (207.5-346.3 mL/g VS) owing to the differences in composition. More importantly, a correlation between the contents of organic components and methane production was established, and then used to predict methane production by VW rapidly. In addition, first-order model, modified Gompertz, and Cone models were used to describe the biochemical methanogenesis mechanism of these VWs. The results of this study can provide a reference for fundamental research on the AD of VW as well as serve a convenient and precise method to predict methane production by different VWs through analyzing compositional components, which will be beneficial for pollution prevention and the comprehensive utilization of VW in the future.

Quercetin: A Bioactive Compound Imparting Cardiovascular and Neuroprotective Benefits: Scope for Exploring Fresh Produce, Their Wastes, and By-Products.

Quercetin, a bioactive secondary metabolite, holds incredible importance in terms of bioactivities, which has been proved by in vivo and in vitro studies. The treatment of cardiovascular and neurological diseases by quercetin has been extensively investigated over the past decade. Quercetin is present naturally in appreciable amounts in fresh produce (fruits and vegetables). However, today, corresponding to the growing population and global demand for fresh fruits and vegetables, a paradigm shift and focus is laid towards exploring industrial food wastes and/or byproducts as a new resource to obtain bioactive compounds such as quercetin. Based on the available research reports over the last decade, quercetin has been suggested as a reliable therapeutic candidate for either treating or alleviating health issues, mainly those of cardiovascular and neurological diseases. In the present review, we have summarized some of the critical findings and hypotheses of quercetin from the available databases foreseeing its future use as a potential therapeutic agent to treat cardiovascular and neurological diseases. It is anticipated that this review will be a potential reference material for future research activities to be undertaken on quercetin obtained from fresh produce as well as their respective processing wastes/byproducts that rely on the circular concept.

Potential Hydrothermal-Humification of Vegetable Wastes by Steam Explosion and Structural Characteristics of Humified Fractions.

In this work, steam explosion (SE) was exploited as a potential hydrothermal-humification process of vegetable wastes to deconstruct their structure and accelerate their decomposition to prepare humified substances. Results indicated that the SE process led to the removal of hemicellulose, re-condensation of lignin, degradation of the cellulosic amorphous region, and the enhancement of thermal stability of broccoli wastes, which provided transformable substrates and a thermal-acidic reaction environment for humification. After SE treatment, total humic substances (HS), humic acids (HAs), and fulvic acids (FAs) contents of broccoli samples accounted for up to 198.3 g/kg, 42.3 g/kg, and 166.6 g/kg, and their purification were also facilitated. With the increment of SE severity, structural characteristics of HAs presented the loss of aliphatic compounds, carbohydrates, and carboxylic acids and the enrichment of aromatic structures and N-containing groups. Lignin substructures were proved to be the predominant aromatic structures and gluconoxylans were the main carbohydrates associated with lignin in HAs, both of their signals were enhanced by SE. Above results suggested that SE could promote the decomposition of easily biodegradable matters and further polycondensation, aromatization, and nitrogen-fixation reactions during humification, which were conducive to the formation of HAs.

Effects of Clonostachys rosea f. catenula Inoculum on the Composting of Cabbage Wastes and the Endophytic Activities of the Composted Material on Tomatoes and Red Spider Mite Infestation.

Globally, fungal inocula are being explored as agents for the optimization of composting processes. This research primarily evaluates the effects of inoculating organic vegetable heaps with the entomopathogenic fungus Clonostachys rosea f. catenula (Hypocreales) on the biophysicochemical properties of the end-product of composting. Six heaps of fresh cabbage (Brassica oleracea var. capitata) waste were inoculated with C. rosea f. catenula conidia and another six were not exposed to the fungus. The composted materials from the fungus- and control-treated heaps were subsequently used as a medium to cultivate tomatoes (Solanum lycopersicum). The biophysicochemical characteristics of the composted materials were also assessed after composting. In addition, the protective effect of the fungal inoculum against red spider mite (Tetranychus urticae) infestations in the tomatoes was evaluated through the determination of conidial colonization of the plant tissue and the number of plants infested by the insect. Furthermore, phytotoxicity tests were carried out post experiment. There were few significant variations (p < 0.05) in heap temperature or moisture level between treatments based on the weekly data. We found no significant differences in the levels of compost macronutrient and micronutrient constituents. Remarkably, the composted materials, when incorporated into a growth medium from fungus-treated heaps, induced a 100% endophytic tissue colonization in cultivated tomato plants. While fewer red spider mite infestations were observed in tomato plants grown in composted materials from fungus-treated heaps, the difference was not significant (χ2 = 0.96 and p = 0.32). The fungal treatment yielded composted materials that significantly (p < 0.05) enhanced tomato seed germination, and based on the phytotoxicity test, the composted samples from the heaps exposed to the C. rosea f. catenula inoculum were not toxic to tomato seeds and seedlings. In conclusion, this study showed that C. rosea f. catenula improved the quality of composted materials in terms of fungal endophytism and seed germination.

Short- and long-term probiotic effects of Enterococcus hirae isolated from fermented vegetable wastes on the growth, immune responses, and disease resistance of hybrid catfish (Clarias gariepinus × Clarias macrocephalus).

This study evaluated the short- and long-term effects of dietary supplementation with Enterococcus hirae strain UPM02 on the growth performance, immunity, and disease resistance of hybrid catfish (Clarias gariepinus × Clarias macrocephalus) against Aeromonas hydrophila infection. In the long-term trial, fingerling fish were fed diets containing 0 (control), 2 × 105, or 2 × 107 CFU/g E. hirae UPM02 for 120 days. Administration of E. hirae UPM02 had significant effects on the specific growth rate (SGR), feed utilization efficiency, body indices (P < 0.05), and gut villus physiology of the catfish. E. hirae UPM02 application also significantly increased the complete blood cell counts, phagocytic activity, respiratory burst, lysozyme activity, and alternative complement pathway hemolytic (ACH50) activity in tested catfish throughout the experimental periods (P < 0.05). Dietary E. hirae UPM02 at both concentrations significantly increased the expression levels of the alpha-2-macroglobulin (α2M), CC chemokines, CXC chemokines, lysozyme c (LYZC), myeloperoxidase (MYE), NF-kappa-B1 p105 subunit (NF-K), and bactericidal permeability-increasing protein (BPIP) genes in the head kidney, liver, and spleen (P < 0.05) at days 80, 100 and 120 after application. However, heat shock protein 70 (HSP70) gene expression was slightly downregulated in these organs. Interestingly, fish fed the diets containing 2 × 105 and 2 × 107 CFU/g E. hirae UPM02 exhibited a significantly lower (P < 0.05) postchallenge mortality rates (32% and 30%, respectively) after 14 days of A. hydrophila challenge than the control fish (58%). In short-term (28 days) application to juvenile catfish, the two concentrations of E. hirae did not affect all growth parameters. Nevertheless, these concentrations markedly elevated all tested immune parameters, similarly to long-term application. Immune-related gene expression was significantly upregulated at day 28 in the head kidney, at day 14 in the liver, and at day 7 in the spleen in fish treated with the two concentrations of the probiotics (P < 0.05). Mortality at 14 days after challenge with A. hydrophila in the groups receiving the two concentrations of the probiotic was significantly lower than that in the control group, at 28, 24, and 48%, respectively (P < 0.05). These results collectively suggest that dietary supplementation with E. hirae UPM02 at 2 × 105 and 2 × 107 CFU/g effectively influenced immune responses, enhanced disease protection, and stimulated immunity-related gene expression in hybrid catfish under both short- and long-term application. However, growth enhancement was significantly evidenced with long-term application only.

Fate of Residual Pesticides in Fruit and Vegetable Waste (FVW) Processing.

Plants need to be protected against pests and diseases, so as to assure an adequate production, and therefore to contribute to food security. However, some of the used pesticides are harmful compounds, and thus the right balance between the need to increase food production with the need to ensure the safety of people, food and the environment must be struck. In particular, when dealing with fruit and vegetable wastes, their content in agrochemicals should be monitored, especially in peel and skins, and eventually minimized before or during further processing to separate or concentrate bioactive compounds from it. The general objective of this review is to investigate initial levels of pesticide residues and their potential reduction through further processing for some of the most contaminated fruit and vegetable wastes. Focus will be placed on extraction and drying processes being amid the main processing steps used in the recuperation of bioactive compounds from fruit and vegetable wastes.

Hyperthermophilic hydrogen production in a simplified reaction medium containing onion wastes as a source of carbon and sulfur.

In this study, the hyperthermophilic dark fermentation of onion wastes (OW) for hydrogen production was investigated. OW were used at different proportions in mixed fruit and vegetable wastes (FVW) to evaluate their effect on hydrogen production by Thermotoga maritima. Fermentations were performed in a pH-controlled batch stirred tank reactor (BSTR) using seawater as a simplified reaction medium. Results showed that increasing OW proportions in total fruit and vegetable wastes (tFVW) improved H2 production. Therefore, increasing the OW to tFVW ratio from 0 to 0.8 increased the cumulative H2 production from 109 to 223.6 mmol/L. The H2 productivity was also improved from 7.3 to 28.82 mmol/h.L. In fact, OW contain carbohydrates, sulfur compounds, and other nutrients, which were used as a carbon source and energetic substrate for H2 production by the halophilic bacterium T. maritima in seawater without additional chemical compounds. Then, a H2 yield of 3.36 mol H2/mol hexose was achieved using 200 mL of OW, containing 55 mmol/L of carbohydrates. A concept of H2 production from FVW at high proportions of OW in a simplified reaction medium was proposed. It allowed a H2 yield of 209 LH2/kg volatile solids which could be an interesting future alternative to the current fossil fuel.

Feeding of processed vegetable wastes to bulls and its potential environmental benefit.

The study was conducted with the objectives to quantify year round availability of different vegetables waste (VW) in a wholesale market and to determine the inclusion level of a processed VW (VWP) in the diets of bulls. The daily VW biomass availability at Kawran bazaar, Dhaka, Bangladesh was quantified by weighing the vegetable supply and their wastes by visiting 2 days in a week. Concurrently, VW of cucumber, bitter gourd, spotted gourd, brinjal, pumpkin, potato, tomato, ladies finger, and snake gourd representing 0.21, 0.18, 0.17, 0.16, 0.09, 0.07, 0.06, 0.03, and 0.02 as fresh fractions, respectively were blended, dried and stored while adding rice polish and common salt at 200 and 20 g/kg DM, respectively; it was tested in bulls as an ingredient of concentrate mixture. Four dietary groups, each of 6 bulls, with initial average live weight (LW) of 85.47 ± 17 kg, were fed fresh German grass (Echinochloa polystachya) ad libitum supplemented with 4 different concentrates containing 0, 10%, 20% and 30% VWP at the rate of 1% of LW for 89 days. The availability of VW biomass of the market was 42.51 t/d and recycling of them as feed, instead of using landfills, might reduce annual methane emission by 0.43 Gg. The inclusion of VWP in the diet up to 9.7% of DM, or 0.30% of LW of bulls showed no significant effect on the DM intake, digestibility, growth performance and health status of bulls. The dietary DM intake represented 3.10%, 3.09%, 3.20% and 3.14% of LW resulting in daily gain of 302, 300, 312 and 344 g, respectively. The digestibility of DM of diets was 56.9%, 62.8%, 62.8% and 63.4%, respectively. It was concluded that VWP may be included at a level of 9.7% of the diet (DM basis) or 0.30% of LW of bulls.

Supercritical Fluid Extraction of Carotenoids from Vegetable Waste Matrices.

The aim of this work was to evaluate a previously-developed model on supercritical fluid extraction (SFE) for carotenoid recovery from carrot peels on various carotenoid-rich fruit and vegetable wastes. To this end, 15 matrices, including flesh and peels of sweet potato, tomato, apricot, pumpkin and peach, as well as flesh and wastes of green, yellow and red peppers, were submitted to SFE under optimised conditions (59 °C, 350 bar, 15 g/min CO2, 15.5% (v/v) ethanol as co-solvent, 30 min of extraction time). The obtained extracts were characterised for their total carotenoid content, antioxidant activity and total carotenoid recovery (TCR). TCR values were greater than 90% w/w for most samples, with ß-carotene being the most successfully extracted compound (TCRs 88⁻100% w/w). More polar carotenoids, such as lutein and lycopene, exhibited lower TCRs. A comparison with literature data suggested that carotenoid extraction is partially dependent on the composition of vegetable matrices, specifically on polysaccharide and moisture content. The results indicated that the optimised SFE conditions can be used as a general model for carotenoid extraction from various fruit and vegetable matrices and as a viable method for adding value to these waste streams by generating carotenoid-rich extracts.

Co-utilization of Crude Glycerol and Biowastes for Producing Polyhydroxyalkanoates.

Polyhydroxyalkanoate (PHA) production by Bacillus thuringiensis EGU45 and defined mixed culture of Bacillus spp. were studied by using crude glycerol (CG) and hydrolyzed biowastes as feed material. Hydrolysates from onion peels (OP), potato peels, pea-shells (PS), apple pomace 2% total solids obtained with defined mixed hydrolytic cultures (MHC2) were inoculated with B. thuringiensis EGU45 and defined mixed bacterial cultures (5MC1), which produced PHA at the rate of 40-350 and 65-450 mg/L, respectively. Addition of CG (1%, v/v) to these hydrolysates resulted in 1.8-fold and 4.5-fold enhancement in PHA production from OP by B. thuringiensis EGU45 and 5MC1, respectively. Co-utilization of OP and PS (in 2:1 ratio) supplemented with CG (1%, v/v) by B. thuringiensis EGU45 resulted in 2-fold increase in PHA production in comparison to OP + CG. This co-metabolism of OP and PS also enabled PHA co-polymer production (1300 mg/L), having an enhanced HV content of 21.2% (w/w).

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.

Succinic acid production from fruit and vegetable wastes hydrolyzed by on-site enzyme mixtures through solid state fermentation.

In this study, a novel biorefinery concept of succinic acid (SA) production from fruit and vegetable wastes (FVWs) hydrolyzed by crude enzyme mixtures through solid state fermentation was designed. Enzyme complex solid mashes from various types of FVWs were on-site produced through solid-state fermentation by Aspergillus niger and Rhizopus oryzae. This solid was then added to FVW suspensions and undergo hydrolysis reaction to generate fermentable sugars and other essential nutrients for bacterial growth and product formation. The subsequent fungal hydrolysis produced 12.00g/L glucose and 13.83g/L fructose using 10% mass ratio (w/v) of FVW. Actinobacillus succinogenes used this FVW hydrolysate as the sole feedstock and produced 27.03g/L of succinic acid with high yield and productivity of 1.18gSA/g sugar and 1.28gL-1h-1, respectively. This work demonstrated that FVWs can be biotransformed to value added products which have considerable potential economics and environmental meaning.

Biohydrogen production from hyperthermophilic anaerobic digestion of fruit and vegetable wastes in seawater: Simplification of the culture medium of Thermotoga maritima.

Biohydrogen production by the hyperthermophilic and halophilic bacterium T. maritima, using fruit and vegetable wastes as the carbon and energy sources was studied. Batch fermentation cultures showed that the use of a culture medium containing natural seawater and fruit and vegetable wastes can replace certain components (CaCl2, MgCl2, Balch's oligo-elements, yeast extract, KH2PO4 and K2HPO4) present in basal medium. However, a source of nitrogen and sulfur remained necessary for biohydrogen production. When fruit and vegetable waste collected from a wholesale market landfill was used, no decreases in total H2 production (139 mmol L-1) or H2 yield (3.46 mol mol-1) was observed.