Half of the fruits and vegetables grown around the world never reach a human mouth. According to a systematic review published in Green Technology, Resilience, and Sustainability, roughly 61 percent of the global fruit harvest and nearly 40 percent of vegetable crops are wasted or lost, drawing on production figures of 883.42 million metric tons of fruit and 588.25 million metric tons of vegetables. Those discarded peels, seeds, pomace, and pulp are not merely an environmental liability, the review argues, but an untapped reservoir of fiber, micronutrients, and bioactive compounds that could be converted into functional ingredients for the food industry.
The review, authored by Desta Dugassa Fufa and Dessalegn Legese Negewo and published on 23 September 2026, was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. The authors searched Scopus, PubMed, Web of Science, Google Scholar, Science Direct, and CAB Abstracts, and their initial search retrieved 1,272 articles. After screening abstracts, removing duplicates, and excluding unrelated studies such as policy documents, 1,051 articles were eliminated. The full texts of 146 articles were then reviewed, and 42 were excluded because of incomplete or inconsistent outcomes or differences in objectives, leaving 126 articles in the final narrative synthesis. Publications considered in the review spanned the years 2000 to 2022.
The scale of the waste problem the authors document is striking. Each year, approximately 1.3 billion tons of food are wasted or lost, about one-third of all food produced, generating economic losses of 940 billion US dollars globally and 310 billion dollars in poor countries annually. In developing countries, waste including roots and tubers represents 40 to 50 percent of total waste. At the household level, the global food waste index shows the household sector generating the largest share at 52 percent, followed by food service at 25 percent and food retail at 23 percent.
The waste streams themselves are chemically rich. Fruit and vegetable processing waste makes up 40 to 60 percent of the total mass handled by processing companies, composed of seeds, pulp, peels, and pomace that account for 10 to 35 percent of raw material mass. These residues contain phenolic compounds, carotenoids, total dietary fiber in the form of cellulose, hemicellulose, lignin, and pectin, macronutrients such as carbohydrates, proteins, and fats, micronutrients including vitamins and minerals, enzymes, sterols, and other low-molecular-weight chemicals. In a frequently cited comparison, the peels of avocados, grapes, and mangoes, along with lemon seeds and jackfruit seeds, were found to contain phenolic concentrations approximately 15 times higher than the corresponding fruit pulp. Waste fractions vary by crop: citrus production wastes 50 to 65 percent of the fruit, mango 15 to 60 percent, avocado 30 to 45 percent, and watermelon 20 to 48 percent, while pineapple processing yields 14 percent peels, 9 percent core, and 15 percent top as by-products.
The physical and chemical properties of these materials shape how they can be processed. Food waste typically has a high moisture content of 50 to 80 percent on a wet-basis weight, and bulk densities ranging from 120 to 480 kilograms per cubic meter, with higher density indicating lower porosity and greater compaction. The pH of fruit and vegetable waste generally falls between 3.9 and 7.5 depending on composition, an acidic character that influences microbial function during biological conversion. The review notes that optimal pH ranges differ by application, with hydrogen production favoring pH 5.0 to 5.5 and methane production pH 6.9 to 7.3. These parameters matter because they determine whether a given waste stream suits drying, fermentation, extraction, or other valorization routes.
Valorization, as the authors define it, is the alteration of waste and biomass into useful, valuable materials such as energy, fuels, and other value-added products with an emphasis on environmental indicators and sustainability goals. They identify four principal techniques: biofuel production, retrieval and isolation of beneficial components, manufacturing of bio-based absorbents for sewage purification, and fabrication of biocompatible materials. Yet the review is candid about the obstacles. Few strategies have been applied at wide scale, and cost effectiveness remains the central barrier, because the high expenses of transporting, collecting, and storing garbage can push the price of end products beyond competitiveness with conventional options. Technical limitations in converting extracted substances into value-added products and an insufficient legal framework for waste disposal add further friction.
On the food application side, the review catalogs a growing repertoire of uses. Dietary fiber concentrates derived from food waste can serve as bulking ingredients while also acting as sources of antioxidants and prebiotics. Pomace, the press residue from fruit processing, can be incorporated into cereal-based extrudates to boost nutritional value, and bakery trials illustrate the potential: biscuits made with white grape pomace blended into wheat flour at 10, 20, and 30 percent levels and baked at 205 degrees Celsius for 11 minutes showed a significant difference from control wheat flour products, with the 10 percent pomace blends improving nutritional quality and remaining well accepted by tasters. Fruit and vegetable by-products can also be formulated into antimicrobial active packaging, where natural biopolymers such as starch, cellulose, pectin, and agar, or food industry by-products like gelatin, whey protein, and chitosan, form edible films and coatings that protect against moisture loss, act as gas barriers, and improve microbial quality. Even laboratory microbiology stands to benefit, as orange peel, cauliflower stalk, fenugreek stem, and potato peel have been formulated as cheap alternatives to standard bacterial culture media, supporting the growth of Pseudomonas species, Escherichia coli, and Serratia species.
Extraction technology occupies a central place in the review. Conventional methods, including solid-liquid extraction, Soxhlet extraction, and liquid-liquid extraction, draw criticism for high solvent consumption, toxic chemical effluents, non-compliance with green technology principles, heavy energy use, risks of thermal damage to heat-labile components, and long extraction durations. The emerging alternatives surveyed include supercritical fluid extraction, microwave-assisted extraction, ultrasound-assisted extraction, pressurized liquid extraction, pulsed electric field extraction, enzyme-assisted extraction, and ionic liquid extraction. The authors specify criteria that green extraction technology should meet: reliance on renewable and sustainable resources, use of non-harmful solvents, energy efficiency, co-product recovery, minimization of unit operations, effective recovery of functional ingredients, and non-hazardous waste emissions. Enzyme-assisted extraction and supercritical fluid extraction are highlighted as particularly suitable for heat-sensitive bioactive compounds. Pre-extraction preparation also matters, with particle sizes finer than 0.5 millimeters generally enhancing extraction, and one study reporting that nanoparticle powder of Centella asiatica produced by planetary ball mill yielded 82.09 percent more than micro powder obtained by maceration in 90 percent methanol over three days.
The review’s conclusions are measured rather than triumphant. Most current intervention strategies, the authors write, remain in early-stage development, leaving a critical need for technological refinement and scale-up, and applying emerging extraction methods to by-products is itself identified as a limited research gap. The limitations section is equally forthright: the study could not perform a meta-analysis because of heterogeneous reporting across studies, and it relies on laboratory-scale data that overlooks real-world challenges such as the supply chain logistics of collecting and stabilizing perishable, seasonal waste streams. Extracting a compound and adding it to food does not guarantee the body absorbs it, and evaluating whether green-extracted ingredients retain their bioactivity after food processing and digestion remains critical. Gaps in industrial scale-up, process economics, life cycle assessment, regulatory frameworks, and consumer sensory acceptance are all flagged as unresolved.
What the review ultimately offers is a map of a field in formation. Fruit and vegetable by-products are positioned as sources of bioactive compounds, biopolymers, and natural antioxidants that should be valorized rather than landfilled, with potential payoffs spanning human nutrition, environmental sustainability, and economic growth within a resilient circular bioeconomy. The authors call for cross-sectoral research and industry partnerships, energy-efficient stabilization technologies such as solar dryers and biorefining, robust supply chains potentially supported by waste brokers, and future research focused on food matrix interactions, optimal dosing, and human bioavailability.
Subject of Research: Valorization of fruit and vegetable waste into sustainable food ingredients using green extraction methods
Article Title: Valorizations, green extraction methods, and application of fruits and vegetables waste for sustainable food ingredients in the food industry: implications of the circular economy
Article References: Fufa, D. D., & Negewo, D. L. (2026). Valorizations, green extraction methods, and application of fruits and vegetables waste for sustainable food ingredients in the food industry: implications of the circular economy. Green Technology, Resilience, and Sustainability, 6(1), Article 14. https://doi.org/10.1007/s44173-026-00039-7
Image Credits: AI Generated
DOI: 10.1007/s44173-026-00039-7
Keywords: food waste, fruit and vegetable by-products, circular economy, green extraction, systematic review, bioactive compounds, dietary fiber, supercritical fluid extraction, active packaging, food industry, sustainability, valorization
News Source: Sloane Callahan. (October 28, 2026). Turning Fruit and Vegetable Waste into Sustainable Food Ingredients. Scienmag.
