Agro-industrial By-products Research Articles

Production of high-calorific hybrid biofuel pellets from urban plastic waste and agro-industrial by-products

Advances in waste-to-energy technology and sustainable fuel production drive significant changes in the energy industry. These innovative solutions not only address waste management challenges but also contribute to broadening the energy source matrix and reducing dependence on traditional fossil fuels. This study evaluates the incorporation of polyethylene and polypropylene urban plastic waste in various agro-industrial by-product blends, which combine beet pulp, radiata pine, and eucalyptus bark wastes. The generation of the hybrid biofuel from agro-industrial waste and domestic solid waste in pellet form is investigated to determine the optimal blends in terms of durability, ash generation and calorific value. Both urban plastics incorporated in the mixtures not only significantly increase the calorific energy value but also promote the binding of the solid biofuel components. The polypropylene-based urban plastic pellet exhibited superior binding capacity and lower ash generation, even in complex hydroxyl functional groups. It also displayed suitable properties for solid biofuels, such as low fine content, high durability, and dimensional stability. The highest resulting calorific value of 22.6 MJ/kg was determined for the mass ratio of the blend with 99% durability, 0.23% fines content, and 5.1% combustion ash generation. This new hybrid biofuel is presented as a sustainable option and a significant contribution in the field of waste-to-energy technology and renewable energy production. The production cost of the hybrid biofuel is competitive with wood-based biofuels, with only a 6.25% increase observed for pellets made from 50% wood and 20% beet pulp compared to traditional 100% wood pellets. However, significant cost reductions were achieved through specific configurations, resulting in savings of 14.8%. The novel hybrid biofuel requires only 9.2 MJ/kg to produce 22.6 MJ/kg, demonstrating significant energy impact and viability as a sustainable energy source in waste-to-energy technology and renewable energy production.

Biochemical and microbial characterization of a forest litter-based bio-fertilizer produced in batch culture by fermentation under different initial oxygen concentrations.

This work focused on the physico-chemical, biochemical and microbiological characterization of a new organic fertilizer based on fermented forest litter (FFL) mixed with agro-industrial by-products, on the culture realized in airtight glass bottle. Under strict anaerobiosis (0% initial oxygen concentration (IOC)), after a 16-day batch culture, the bottle-headspace analysis showed that the specific CO2 production rate was low (0.014 mL/h.g dry matter) compared to those reached under aerobic conditions (e.g. 0.464 mL/h.g dm at 21% IOC). Moreover, the culture displayed a slight fermented fruity odour, mainly due to ethanol and ethyl acetate detected in the headspace (335 µL and 58.6 µL accumulated, respectively). The FFL organic matter degradation followed by infrared spectroscopy and catabolic potential and diversity characterized by BIOLOG® EcoPlates were poor and pH dropped to 4.54. The microbiome's metabolism was oriented toward lactic fermentation with medium acidification, enrichment in lactic acid bacteria (LAB), depletion in fungi and absence of pathogens. By increasing IOC from 0 to 21%, the respirometric activity, and the catabolic potential and diversity increased. However, some enterobacteria were detected above 5% IOC. Ethanol and ethyl acetate decreased strongly with IOC, and aromatics and proteins contained in the solid matrix remained in the culture. This study showed the importance of oxygen on the final product. A 2% IOC was found to ensure an optimal balance between LAB development, preservation of functional catabolic diversity and bio-product free of microbial pathogens.

Prickly pear (Opuntia ficus-indica) dehydrated envelopes and seed cakes in Coturnix coturnix feed: effects on growth performance, carcass characteristics, meat quality and blood biochemical profiles.

The valorization of agro-industrial byproducts in domestic animal feed has the potential to reduce the cost of animal production. This trial was conducted to determine the effect of incorporating prickly pear byproducts (envelopes and cakes) as a partial substitute for corn and soybean meal in the diet of wheat quails (Coturnix coturnix) during their rearing period. Six hundred-day-old Coturnix coturnix quails of equal sex ratio (1:1), weighing on average 7 ± 0.5g, were randomly distributed into four groups, one control group and three experimental groups, according to the rates of incorporation of prickly pear cakes and envelopes, in sequential or nonsequential mode, in the different rearing phases. Each batch (150 subjects) was subdivided into five packs of 30 animals and randomly distributed according to the rate of incorporation (0%, 10%, 20% and 30%) of prickly pear envelopes and cakes. The live weight at 45 days and average daily gain (ADG1 - 45d) increased significantly with the introduction of byproducts in all rearing phases (SFCEPP). The carcass yield increased significantly (p < 0.05) with the introduction of byproducts in the finishing phase (FCEPP) and in all rearing phases (SFCEPP). The mineral content decreased significantly (p < 0.05) in all the experimental groups. The protein content increased significantly by 2 points on average when the two prickly pear byproducts were introduced in all rearing phases. The blood biochemical profile of each experimental batch was not influenced by the incorporated prickly pear byproducts. Prickly pear envelopes and cakes in wheat quail feed improve growth performance and meat quality, particularly when they are introduced in the finishing phase and in all rearing phases.

Copper nanoparticles biosynthesis by Priestia megaterium and its application as antibacterial and antitumor agents

The growth of material science and technology places high importance on creating better processes for synthesizing copper nanoparticles. Thus, an easy, ecological, and benign process for producing copper nanoparticles (CuNPs) has been developed using Priestia sp. bacteria utilizing a variety of low-cost agro-industrial wastes and byproducts. The biosynthesis of CuNPs was conducted using glucose medium and copper ions salt solution, then it was replaced by utilizing low-cost agro-industrial wastes. UV–visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), High-resolution transmission electron microscope (HR-TEM), Attenuated Total Reflectance and Fourier transform infrared (ATR-FTIR), and zeta potential were used to characterize the biosynthesized CuNPs. The cytotoxicity of CuNPs using Vero -CCL-81 cell lines, and antibacterial and antitumor properties using human colon epithelial colorectal adenocarcinoma Caco-2-HTB-37 cell lines were assessed. The UV–visible and DLS studies revealed CuNPs formation, with a maximum concentration of 6.19 ppm after 48 h, as indicated by a 0.58 Surface plasmon resonance (SPR) within 450 nm and 57.73 nm particle size. The 16S rRNA gene analysis revealed that Priestia sp. isolate is closely related to Priestia megaterium and has been deposited in the NCBI GenBank with accession number AMD 2024. The biosynthesis with various agro-industrial wastes indicated blackstrap sugar cane molasses being the most effective for reducing CuNPs size to 3.12 nm owing to various reducing and stabilizing active compounds. The CuNPs were free of contaminants, with a sphere-shaped structure and a cytotoxicity assessment with an IC50 of 367.27 μg/mL. The antibacterial activity exhibited by the most susceptible bacteria were Bacillus cereus ATCC 11788 and Staphylococcus aureus ATCC 6538 with inhibition zones of 26.0 mm and 28.0 mm, respectively. The antitumor effect showed an IC50 dose of 175.36 μg/mL. Based on the findings, the current work sought to lower product costs and provide a practical solution to the environmental contamination issues brought on by the buildup of agricultural wastes. In addition, the obtained CuNPs could be applied in many fields such as pharmaceuticals, water purification, and agricultural applications as future aspects.

Domestication of wild-growing Turkey tail mushroom (Trametes versicolor) from Ethiopian forests on augmented agro-industrial byproducts

Despite being extensively studied as a white-rot fungus, there have been no efforts to explore and cultivate the high-yielding wild Trametes versicolor strains in Ethiopia. Thus, this study was initiated to assess the growth performance of T. versicolor on various growth media. Accordingly, ten substrates (S1–S10) were formulated by a combination of agro-industrial by-products that mainly constituted sugarcane wastes and animal manures. The effect of substrates on yields, biological efficiencies, and nutritional compositions was examined. The mushroom developed a white mycelium on the growth media. T. versicolor cultivated on the S5 blend, comprising 80% sugarcane bagasse, 12% horse manure, and 8% poultry manure, exhibited the most substantial fruiting body yield (158.33 g/500 g bag) and the highest biological efficiency (31.5%), with an optimal C:N ratio of 31:1. It has shown good mycelial growth, short colonization, and short pinhead formation time compared to other substrates. S7, lacking nitrogen supplementation, yielded low biological efficiency and fruiting bodies at 11.50% and 57.67%, respectively. The crude protein, fiber, low fat, and carbohydrate content ranged from 7.46 to 14.65%, 12.89 to 18.38%, 0.42 to 0.53%, and 48.75 to 66.75%, respectively. Notably, the highest nutritional values, excluding carbohydrates, were obtained from S5, while the sugarcane bagasse had the highest carbohydrate content among substrates. Consequently, S5 emerged as a suitable medium for cultivating wild T. versicolor mushrooms, particularly in regions abundant in poultry, horse manures, and sugarcane bagasse. Therefore, S5 represents an optimal substrate for T. versicolor cultivation, offering improved productivity and nutritional quality at reduced costs.

VALORIZATION OF BANANA FLOWER RESIDUES: POTENTIAL THERAPEUTIC AND ANTIOXIDANT APPLICATIONS

Various parts of the banana tree (Musa spp.), such as leaves, fruits, inflorescences, roots, peels and stems are used in traditional medicine, in several cultures around the world, for the treatment of diarrhea, ulcers, pain, inflammation, and diabetes mellitus. The inflorescence, in turn, stands out as a promising by-product of the banana agroindustry, since it is rich in micronutrients and bioactive compounds relevant to the human health, such as β-sitosterol, flavonoids, saponins, and phenolics like catechin and isoquercetin. Studies reveal that the consumption of banana inflorescences can provide various health benefits, including improved intestinal function, weight management and reduced risk of cardiovascular diseases. For this work, a bibliographic narrative review was carried out with a focus on the valorization of banana flower residues, exploring its therapeutic and antioxidant potential. The research was developed through the analysis of scientific articles and relevant studies, highlighting the bioactive properties of these by-products and their potential applications in the pharmaceutical and food industries. This review showed that banana inflorescences are rich in phenolic compounds, flavonoids and terpenoids, which have antioxidant, antidiabetic, anti-inflammatory and antimicrobial properties. Therefore, these by-products can be used by the pharmaceutical and food industries and can contribute to the circular economy and sustainable management of agricultural resources.

Pilot scale production of high-content mycoprotein using Rhizopus microsporus var. oligosporus by submerged fermentation and agro-industrial by-products

While mycoprotein has gained traction as a human food source, its potential as a nutrient for animals remains largely unexplored. The mycoprotein-producing Rhizopus microsporus var. oligosporus, a fungus traditionally used for human food in Indonesia, is promising. It could revolutionise animal nutrition once it is Generally Recognized as Safe (GRAS) and is a biosafety level 1 (BSL1) organism. To enhance sustainably, we propose using sugar cane molasses (SM) and corn steep liquor (CSL) as nutrient sources. Also, we investigated the growth of R. microsporus var. oligosporus in five 14 L external-loop airlift bioreactors using CSL as the sole nutrient source. After 96 h of fermentation, at 25 °C and 0.5 vvm, the mycelium produced had an average biomass yield of 38.34 g L−1, with 70.18 % (m v−1) crude protein (mycoprotein). This bioprocess, which is scalable and economically viable, produces high amounts of mycoprotein for animal feed using CSL, a cost-effective agro-industrial by-product, providing a practical solution to the growing demand for animal protein.

Consumers' attitudes, perceptions and willingness to try hazelnut skins-fed beef

Consumers are raising concerns over the ethical and social acceptability of feeding regimes used in animal-based food productions. However, the use of agro-industrial by-products, such as hazelnut skins as a strategy to reduce the environmental impact of livestock production may be negatively perceived from the consumer's perspective. Here, we investigated the factors predicting consumers' intentions to try meat obtained from cattle fed hazelnut skins. Nine hundred Italian regular meat consumers were recruited via an online provider of market research panels. Three different framings were presented to consumers as meat products fed with food industry by-products vs possessing either feed quality or an environmental benefit. Consumers generally responded positively to the product when they were informed that it helps promote sustainable production, reduces food waste, or improves feed quality, with no significant difference between framings. Consumers who reported not to be very concerned about feeding methods and to have a low green self-identity tended to be more skeptical towards the use of alternative feeds. The level of neophobia significantly influenced the respondents' risk perceptions. Our findings suggest that product characteristics and risk and benefit perceptions will significantly influence the acceptance of hazelnut skins as feed ingredient. The factor “environmental benefits” was a key predictor of “willingness to try”, while concerns about the potential health effects were identified as a major barrier to accepting novel feed alternatives. This research confirms the great need to educate consumers in order to empower meat choices that are environmentally friendly at the production system level.

Protein Hydrolysates—Production, Effects on Plant Metabolism, and Use in Agriculture

Agriculture is facing challenges to produce more food in a climate scenario that works in the opposite direction. To amend this, agriculture has to invent new ways of making more with less. Interest in using by-products and finding new ways to utilize them has been increasing in recent years. The use of protein-rich sources for protein hydrolyzation and the use of these protein hydrolysates as biostimulants in plant production have been increasing. These mixtures are mainly produced by chemical and enzymatic hydrolysis from agro-industrial protein-rich by-products of animal, plant, and algal origins. The application of PHs has the potential to alleviate environmental stress; improve plant growth; and increase productivity, fruit yield, and abiotic-stress tolerance in agricultural crops. The use of these biostimulants offers a way to reduce the use of agrochemicals and agrees with the “do more with less” task in the future of agricultural production. This review gives an insight into the production of PHs, referring to sources of raw materials and methods of hydrolysis, the uptake and translocation of PHs, their effect on plant growth, the development and physiology, their role in alleviating stressful conditions, and their use in agriculture. The beneficial effects of PHs on different aspects of plant physiology, metabolism, and plant functioning under stressful conditions are evident. Inconveniently, crops, and sometimes even cultivars, are affected differently based on the way that PH is applied, the timing, and the concentration applied. Further research is needed to elucidate the mechanisms by which the components of PHs modify plant physiology and metabolism.

Experimental Design, Statistical Analysis, and Modeling of the Reduction in Methane Emissions from Dam Lake Treatment Using Agro-Industrial Biochar: A New Methane Capture Index

This study aimed to reduce the methane (CH4) emissions originating from dam lake treatment using malt dust-derived biochar, which is an agro-industrial byproduct of the brewery industry. Optimum operating and water quality parameters for CH4 reduction were determined using statistical analyses based on the Box–Behnken design method. Also, a Monte Carlo simulation was performed to determine the correlation between CH4 emissions and operating parameters. According to the simulation, dissolved oxygen (DO) and the oxidation–reduction potential (ORP) had the highest correlation with CH4 emissions, with values of 92.03% and 94.57%, respectively. According to the Box–Behnken design methodology, the optimum operating parameters were 4 mg/L of dissolved oxygen, −359 mV of ORP, and 7.5 pH for the minimum CH4 emissions. There was a reported reduction of up to 19.4% in CH4 emissions for the dam lake treatment using malt dust-derived biochar. Finally, a new methane capture index, based on the biochar application (MCI), was developed and validated. The largest methane capture capacity was related to the malt dust-derived biochar produced at the lowest temperature (M1).

Evaluation of Polyphenol Profile from Citrus Peel Obtained by Natural Deep Eutectic Solvent/Ultrasound Extraction

Citrus fruits are widely consumed worldwide; however, one of their primary uses is juice production, resulting in over 40 million tons of agro-industrial waste. Citrus peel is the main agro-industrial by-product in citrus production. In recent years, secondary metabolites of interest, mainly polyphenols such as hesperidin, have been identified in citrus peels. Currently, green alternatives like natural deep eutectic solvents (NADES) based on choline chloride and glucose (Glu), combined with ultrasound-assisted extraction, are studied to obtain polyphenol-rich extracts with potential health applications. This study aims to evaluate the effect of: (1) molar ratios (MR) of 1:0.5, 1:1 or 1:2 mol/mol of choline chloride (ChCl):glucose (Glu); (2) the percentage of added water (WA: 50, 60 or 70%) to NADES; and (3) different citrus peels of Citrus aurantium (bitter orange), Citrus sinensis (sweet orange), and Citrus limon (lemon) used for extraction, on polyphenol profiles, total polyphenol content (TPC), and antioxidant capacity (Ax) of the extracts. The extracts were analyzed using ultra-performance liquid chromatography (UPLC) and evaluated using the Folin–Ciocalteu method for TPC and DPPH assay for quantifying AC. A factorial experimental design 33 was implemented. The extract obtained with an MR of 1:1 (ChCl:Glu) from Citrus aurantium peel exhibited the highest concentration of hesperidin (2003.37 ± 10.91 mg/100 g dry mass), whereas an MR of 1:2 (ChCl:Glu) exhibited the highest concentration of neohesperidin (1045.94 ± 1.27 mg/100 g dry mass), both using 60% WA. This extract also showed the highest antioxidant capacity, achieving 100% inhibition. On the other hand, the highest concentration of total phenolic content (TPC) (96.23 ± 0.83 mg GAE/100 g dry mass) was obtained using C. aurantium peel with an MR of 1:0.5 (ChCl:Glu) and 60% WA. The extracts also presented high concentrations of rutin and catechin. These findings highlight the potential of revalorizing citrus peels, particularly Citrus aurantium, and their extracts obtained with NADES for possible health applications.

The effects of applying cellulase and laccase on fermentation quality and microbial community in mixed silage containing corn stover and wet brewer's grains.

The purpose of this experiment was to explore the effect of adding cellulase and laccase on fermentation quality and microbial community in mixed silage of corn stover and wet brewer's grains. Try to a new approach for the proper preservation and utilization of the agro-industrial by-products (corn stover and wet brewer's grains). The experiment was divided into four groups: CK (control), C (cellulase, 120 U/g fresh matter [FM]), L (laccase, 50 U/g FM), CL (cellulase 120 U/g FW and laccase 50 U/g FM), and the chemical composition, fermentation quality, microbial population and microbial community in mixed silage of corn stover and wet brewer's grains after 30 day's fermentation were determined. Compared to control, the addition of cellulase significantly increased crude protein (CP), water-soluble carbohydrate (WSC), lactic acid bacteria (LAB) counts, while significantly decreased the neutral detergent fiber (NDF), acid detergent fiber (ADF) content (P < 0.05). Adding laccase significantly decreased the acid detergent lignin (ADL) content (P < 0.05). Combined application of cellulase and laccase significantly increased the CP, WSC content and LAB counts, while significantly decreased pH value, NDF, ADF and ADL content (P < 0.05), thereby improving fermentation quality. In addition, the application of cellulase and laccase increased the abundance of Firmicutes and LAB genera, and decreased microbial diversity level of the sample. The combined application of cellulase and laccase further improved fermentation quality and microbial community in mixed silage of corn stover and wet brewer's grains.

Design of experiment approach to boost volatile production from kiwi byproducts

Design of Experiments (DoE), is a tool to explore relationships between factors and responses of a system. DoE and response surface methodology are increasingly used in different fields, but their application are limited in the valorization of residual biomass and agro-industrial by-products. Agro-industrial biomass residues can be eco-friendly converted into high-value compounds through bioprocesses. This approach identified key factors and predicted optimal conditions for enhancing microbial growth and the production of specific compounds or volatile classes. Lactiplantibacillus plantarum 4193 and Lacticaseibacillus paracasei 2243, were identified as the best starters while the production of methyl heptenone is influenced by fermentation time and pH. This out-turn in the generation of aromatically rich biomass, which can be utilised as a food ingredient or for the extraction of specific volatile compounds, and employed as flavouring agents. This study underlines the potential of fermentation in maximizing the value of unripe kiwi biomass.

The Use of Pomace as Animal Feed: A Review of Grape and Tomato Pomace

Pomace is generated in large quantities yearly; high water content and bulkiness make it difficult to be easily disposed of thereby contributing to environmental pollution and providing breeding space for flies which can transmit diseases. Incorporating the pomace generated from grape and tomato fruits in animal nutrition will improve sustainable agriculture; the animals will also benefit from the polyphenols in the pomace which can improve their antioxidant status thereby improving animal health and welfare. Pomace consists of unfermentable sugars, tannins, anthocyanins, lycopene, and cellulose which have natural antioxidants, anti-inflammatory and antimicrobial properties. This review focused on the utilization of grape and tomato pomace as feedstuff for animals, the knowledge gap in the use of pomace in animal nutrition was also outlined. Supplementation of pomace generated from grape and tomato was evaluated on animal growth and reproductive performance, health, oxidative stress, animal products and gut health. In conclusion, incorporating agro-industrial byproducts into animal diet can be beneficial to farm animals by improving their health, welfare, performance as well as the environment, thereby leading to a more sustainable agricultural practice.

Innovative sustainable bioreactor-in-a-granule formulation of Trichoderma asperelloides

The advancement of fungal biocontrol agents depends on replacing cereal grains with low-cost agro-industrial byproducts for their economical mass production and development of stable formulations. We propose an innovative approach to develop a rice flour-based formulation of the beneficial biocontrol agent Trichoderma asperelloides CMAA1584 designed to simulate a micro-bioreactor within the concept of full biorefinery process, affording in situ conidiation, extended shelf-life, and effective control of Sclerotinia sclerotiorum, a devastating pathogen of several dicot agricultural crops worldwide. Rice flour is an inexpensive and underexplored byproduct derived from broken rice after milling, capable of sustaining high yields of conidial production through our optimized fermentation-formulation route. Conidial yield was mainly influenced by nitrogen content (0.1% w/w) added to the rice meal coupled with the fermentor type. Hydrolyzed yeast was the best nitrogen source yielding 2.6 × 109 colony-forming units (CFU)/g within 14 days. Subsequently, GControl, GLecithin, GBreak-Thru, GBentonite, and GOrganic compost+Break-Thru formulations were obtained by extrusion followed by air-drying and further assessed for their potential to induce secondary sporulation in situ, storage stability, and efficacy against Sclerotinia. GControl, GBreak-Thru, GBentonite, and GOrganic compost+Break-Thru stood out with the highest number of CFU after sporulation upon re-hydration on water-agar medium. Shelf-life of formulations GControl and GBentonite remained consistent for > 3 months at ambient temperature, while in GBentonite and GOrganic compost+Break-Thru formulations remained viable for 24 months during refrigerated storage. Formulations exhibited similar efficacy in suppressing the myceliogenic germination of Sclerotinia irrespective of their concentration tested (5 × 104 to 5 × 106 CFU/g of soil), resulting in 79.2 to 93.7% relative inhibition. Noteworthily, all 24-month-old formulations kept under cold storage successfully suppressed sclerotia. This work provides an environmentally friendly bioprocess method using rice flour as the main feedstock to develop waste-free granular formulations of Trichoderma conidia that are effective in suppressing Sclerotinia while also improving biopesticide shelf-life.Key points• Innovative “bioreactor-in-a-granule” system for T. asperelloides is devised.• Dry granules of aerial conidia remain highly viable for 24 months at 4 °C.• Effective control of white-mold sclerotia via soil application of Trichoderma-based granules.

Bioactive compounds from agroindustrial byproducts and their applications: From traditional methods to green technologies

The use of agroindustrial byproducts (solids and liquids) with bioactive compounds has developed and grown remarkably. Existing methodologies and some new approaches developed through various research efforts have demonstrated their viability. The bioactive compounds commonly studied in research are phenolic compounds and carotenoids because of their potential as antioxidants and natural additives that can prolong the shelf life of certain foods. Meanwhile, conventional extraction methods are being replaced with green technologies, which offer reduced extraction time and are more environmentally friendly, among other advantages. In addition, protecting and preserving bioactive compounds from environmental conditions by applying microencapsulation and nanoencapsulation methods is crucial. These studies have shown that combining methods yields better results than using them individually. Therefore, it is recommended that unconventional methods and green technologies be integrated into future research. This approach will help determine whether acquiring them is profitable and feasible for the agroindustrial companies responsible for this waste. This review demonstrates the potential use of agricultural byproducts to obtain bioactive compounds (through combined extraction methods for improved efficiency) and incorporate them in different industries, such as food, cosmetics, and aquaculture, thereby creating a favorable socio-environmental impact by reducing soil and water pollution.

Peanut (Arachis hypogaea L.) flour and oilcake flour: Exploring the influence of roasting and varietal differences on proximal composition, elemental profiling, antimicrobial and antioxidant properties

Peanuts are highly valued for their abundance of essential nutrients and health-promoting phenolic compounds. Peanut press cake, an inexpensive and underutilized agro-industrial by-product of oil production, is typically discarded or used as animal feed. This study investigated the influence of thermal processing and varietal disparities on the nutritional composition, phenolic content, and biological properties of peanut flour and oilcake flour, aiming to enhance their value as food ingredients. The findings showed that roasting significantly increased the oil (9.98 ± 0.11–44.13 ± 0.10 %), ash (1.28 ± 0.01–5.45 ± 0.05 %), carbohydrate contents (0.90 ± 0.01–28.09 ± 0.28 %), and energy value (406.69 ± 0.09–609.13 ± 1.08 kcal/100 g), along with the total polyphenol content (28.64 ± 0.19–62.79 ± 1.18 mg GAE/g), total flavonoid content (4.20 ± 0.07–18.35 ± 0.06 mg QE/g) and antioxidant activity in both peanut flour and its oilcake. Conversely, it led to a reduction in the moisture (1.48 ± 0.09–6.25 ± 0.15 %) and protein content (49.50 ± 0.05–54.24 ± 0.01 %). Notable variations were found between the two peanut varieties in terms of these nutritional parameters. Elemental analysis unveiled significant discrepancies among peanut varieties and with roasting, with potassium (12,237.56 ± 101.36–14,513.34 ± 168.62 mg/kg) emerging as the predominant macro-element followed by phosphorus (6156.86 ± 36.19–8815.22 ± 130.70 mg/kg) and magnesium (3037.92 ± 13.87–4096.44 ± 8.54 mg/kg), while zinc (53.98 ± 0.61–81.77 ± 0.44 mg/kg) predominated among the microelements. Moreover, peanut and oilcake flours demonstrated antibacterial activity against several bacteria. It can be inferred that roasted peanut and oilcake flours offer substantial nutritional value, making them promising candidates for addressing protein-energy malnutrition and serving as valuable ingredients in developing new food products.

Evaluating the dynamic effects of complex probiotics as cellulase replacements during fermentation of apple pomace

Apple pomace, an abundant agricultural by-product with low utilization rates, often leads to environmental pollution if not properly managed. This study aimed to enhance the nutritional value of apple pomace by comparing the effects of solid-state fermentation using complex probiotics and cellulase preparation. Additionally, the study investigated the dynamic changes in various components throughout the fermentation process with complex probiotics. The results of single-strain solid-state fermentation tests indicated that Lactiplantibacillus plantarum DPH, Saccharomyces cerevisiae SC9, and Bacillus subtilis C9 were the optimal strains for fermenting the most effective substrate combination, comprising 73 % apple pomace and 20 % millet bran. The strains (complex probiotics) and a cellulase preparation were used for the solid-state fermentation of the apple pomace mixture for nine days, respectively. The contents of acid detergent fiber, neutral detergent fiber, hemicellulose, and insoluble dietary fiber decreased by up to 9.99 %, 9.59 %, 23.21 %, and 14.34 %, respectively. In contrast, the content of soluble dietary fiber significantly increased by up to 29.74 %. Both methods reduced cellulose crystallinity and modified the substrate's surface structure, resulting in a looser arrangement. Fermentation with complex probiotics for three or six days increased the abundance of lactic acid bacteria, which comprised >87 % of the total microbial population. Concurrently, the abundance of detrimental bacteria, such as Salmonella, Acetobacter, Escherichia, and Pantoea, significantly decreased. Furthermore, fermentation with complex probiotics for six or nine days enhanced antioxidant properties, leading to a significant increase in beneficial metabolites, including amino acids, organic acids, gamma-aminobutyric acid, serotonin. In conclusion, complex probiotics can effectively substitute for cellulase preparation in the solid-state fermentation of apple pomace, with a six-day fermentation period yielding optimal results. This study provides valuable insights into enhancing the value of apple pomace in the feed industry and the effective application of agro-industrial by-products.

Recovery of Phenolic Compounds by Deep Eutectic Solvents in Orange By-Products and Spent Coffee Grounds

Orange and coffee grounds by-products, rich in phenolic bioactive compounds, can be used in the food industry as antioxidants, colorants, flavorings and additives, mainly because they are solvents that are easy to prepare, have a lower cost, are thermally stable, biodegradable, renewable, and are considered GRAS (Generally Recognized as Safe). Deep eutectic solvents, which are sustainable and have lower melting points, are effective for extracting these compounds. This study aimed to evaluate the use of deep eutectic solvents (DES) in extracting Total Phenolic Compounds (TPC), from orange by-products and spent coffee grounds. DES formed by citric acid: mannitol (CM-DES), and lactic acid: glucose (LG-DES), were evaluated by varying the following parameters: water content (10–50%), solid–liquid ratio (1:5–1:50 w/w) and temperature (40–50 °C). DES citric acid: mannitol presented the best efficiency in the extraction of TPC under the conditions of 10% water, 80 °C, and solid–liquid ratio 1:10 (w/w) for the orange by-products (1782.92 ± 4.50 mg GAE/L) and 1:15 (w/w) for spent coffee grounds (1620.71 ± 3.72 mg GAE/L). The highest antioxidant activity was observed in the extraction with CM-DES for both by-products in the three methods evaluated: Ferric Reducing Antioxidant Power (FRAP) (1.087 ± 0.004 and 1.071 ± 0.006 mol ascorbic acid/L), DPPH radical scavenging activity (2,2-difenil-1-picrilhidrazil—DPPH) (0.233 ± 0.003 and 0.234 ± 0.001 mol Trolox equivalent/L), and radical cation scavenging activity ABTS (2,2-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid—ABTS) (0.284 ± 7.16 and 0.319 ± 0.002 mol Trolox equivalent/L). Therefore, DES with citric acid: mannitol is a promising alternative to conventional solvents to recover phenolic compounds in agro-industrial by-products, such as orange by-products and SCG.

Influence of InVitro Digestion on Dipeptidyl Peptidase-IV (DPP-IV) Inhibitory Activity of Plant-Protein Hydrolysates Obtained from Agro-Industrial By-Products.

This study investigates the production of protein hydrolysates with dipeptidyl peptidase-IV (DPP-IV) inhibitory activity from agro-industrial by-products, namely olive seed, sunflower seed, rapeseed, and lupin meals, as well as from two plant protein isolates such as pea and potato. Furthermore, the effect of simulated gastrointestinal digestion on the DPP-IV inhibitory activity of all the hydrolysates was evaluated. Overall, the lowest values of IC50 (1.02 ± 0.09 - 1.24 ± 0.19 mg protein/mL) were observed for the hydrolysates with a high proportion of short-chain [< 1 kDa] peptides (i.e., olive seed, sunflower seed, and lupin) or high content of proline (i.e., rapeseed). Contrarily, the IC50 of the pea and potato hydrolysates was significantly higher (1.50 ± 0.13 - 1.93 ± 0.13 mg protein/mL). In vitro digestion led to an increase in peptides <1 kDa for almost all hydrolysates (except olive and sunflower seed meals), which was noticeable for rapeseed, pea, and potato hydrolysates. Digestion did not significantly modify the DPP-IV inhibitory activity of olive, sunflower, rapeseed, and potato hydrolysates, whereas a significant decrease in IC50 value was obtained for pea hydrolysate and a significant increase in IC50 was obtained for lupin hydrolysate. Thus, this work shows the potential of agro-industrial by-products for the production of protein hydrolysates exhibiting DPP-IV inhibition.