Mango processing can leave behind peel, seed kernel, and pomace amounting to a large share of the fruit. This review asks whether that discarded material could become a sophisticated prebiotic ingredient rather than waste. Mango is one of the most widely produced and processed tropical fruits, with global production exceeding fifty-five million tonnes annually.

Processing mango into juices, purees, concentrates, and dried products generates peel, seed kernel, and pomace as by-products. These residues may represent approximately thirty-five to sixty percent of the total fruit mass, and they are commonly discarded despite containing dietary fiber and bioactive compounds.

That disposal creates environmental and economic burdens, while the residues’ rich composition points toward valorization within a circular bioeconomy framework. The opportunity is not straightforward because cultivar, maturity stage, geographical origin, and processing conditions can change the composition, structure, and fermentability of mango by-products.

Much of the evidence on microbiota modulation still comes from in vitro fermentation models and animal studies, while human clinical investigations remain limited. Although some studies report increases in beneficial microbial populations and short chain fatty acid production, the translation into clinically validated health outcomes is not fully established.

Comparisons with established prebiotics such as inulin and fructooligosaccharides are also relatively scarce, supporting the need for standardized characterization and well-designed human studies. The review brings together compositional characteristics, processing strategies, and mechanisms of gut microbiota modulation to evaluate mango by-products as prebiotic ingredients.

It focuses on structure-function relationships, processing effects on fermentability and bioactivity, and interactions among dietary fiber, polyphenols, and gut microbiota. It also discusses limitations, research gaps, future perspectives, functional application, and clinical validation.

The intended framework is to transform mango by-products from low-value agro-industrial residues into high-value functional ingredients for gut health applications. The prebiotic potential of mango by-products is governed by compositional diversity and structural complexity, which determine resistance to gastrointestinal digestion, fermentability, and subsequent modulation of gut microbiota.

Peel, seed kernel, and pomace have distinct compositional profiles, so they contribute differently to functional performance. Mango peel is particularly rich in dietary fiber and pectin, at approximately five to eleven percent, along with substantial polyphenolic compounds.

The seed kernel is characterized by higher starch content, including resistant starch fractions. Pomace is a heterogeneous matrix influenced by processing conditions such as juice extraction and drying. These compositional attributes vary across cultivars, maturity stages, and processing methods, contributing to variability in functional efficacy.

Dietary fiber structure plays a central role in determining fermentability. Soluble fibers, particularly pectin, are readily fermented by colonic microbiota, whereas insoluble fibers mainly contribute to bulking effects.

Degree of esterification, molecular weight, and branching influence microbial accessibility and fermentation kinetics, linking molecular configuration with microbiota response. Variability in these parameters can lead to inconsistent prebiotic performance.

Processing strategies alter structural properties and, consequently, the functional performance of mango-derived ingredients. Drying, milling, and extraction are used mainly to stabilize raw materials and concentrate bioactive components. Hot-air and freeze-drying affect moisture removal and fiber integrity, while excessive thermal exposure may degrade pectin and associated bioactives.

Milling increases surface area and substrate accessibility, while extraction conditions determine pectin yield, degree of esterification, and molecular structure. However, conventional methods offer limited control over molecular characteristics and often do not optimize fermentability.

The relationship between processing and prebiotic functionality is governed by structural modifications, particularly changes in molecular weight and polymer configuration. Controlled depolymerization enhances fermentability, but excessive degradation can compromise functional stability and reduce sustained substrate availability in the colon.

This creates a trade-off between maximizing microbial accessibility and preserving structural integrity. Enzymatic approaches provide greater specificity and functional control, while physical methods offer advantages in scalability and cost-efficiency.

Integrated processing that combines controlled extraction with targeted enzymatic modification is presented as a promising pathway for consistent, high-performance prebiotic ingredients. Mango-derived substrates undergo coordinated microbial fermentation and polyphenol biotransformation within the colon, producing multifaceted mechanisms of gut microbiota modulation.

Dietary fiber and oligosaccharide fractions, particularly pectic oligosaccharides, resist digestion in the upper gastrointestinal tract and reach the colon. In the colon, these fractions serve as substrates for microbial fermentation.

Selective fermentation shifts microbial ecology toward beneficial bacteria such as Bifidobacterium and Lactobacillus. Butyrate-producing bacteria such as Faecalibacterium and Roseburia contribute to short chain fatty acid production through cross-feeding interactions, supporting microbial diversity and metabolic activity.

These microorganisms have specialized enzymatic systems that degrade complex polysaccharides, enabling selective utilization of mango-derived substrates. The process produces short chain fatty acids, predominantly acetate, propionate, and butyrate, which support colonic health and regulate epithelial function.

Butyrate is considered especially important for colonic health because colonocytes use it to generate energy, it stabilizes hypoxia-inducible factor, and it maintains gut barrier integrity. These metabolites also support the intestinal barrier through modulation of mucus production and tight junction integrity.

Mango-derived substrates modulate gut microbiota through interconnected mechanisms involving carbohydrate fermentation, polyphenol transformation, pathogen inhibition, and microbial cross-feeding. These mechanisms are further illustrated in Fig.

2. Dietary fibers primarily act as classical prebiotic substrates through selective microbial utilization. Polyphenols contribute predominantly through microbial biotransformation, microbial interactions, and generation of bioactive postbiotic metabolites.

Reading across the table, the fiber pathway links pectin and POS to acetate and propionate, with acidification and host energy listed as outcomes. The starch row instead traces resistant starch through the R. bromii to Roseburia/E.

rectale axis to butyrate and an anti-inflammatory outcome, while the final row connects POS with reduced pathogens and infection control. Reading left to right, the figure organizes the mechanism into six numbered stages, from prebiotic components and colon arrival through fermentation, metabolite production, host responses, and barrier maintenance.

In the lower intestinal panel, arrows and symbols connect these stages to microbial colonization, pathogen blocking, antimicrobial substances, and strengthened epithelial junctions, making the proposed sequence visible rather than presenting a quantitative comparison. Short chain fatty acid production is frequently reported, but direct links to clinically relevant health outcomes remain insufficiently established, particularly in human studies.

Variability in substrate composition and processing conditions introduces inconsistencies in microbiota responses and complicates mechanistic interpretation. The evidence supports mango by-products as multifunctional prebiotic systems, but integrated understanding of microbiota dynamics, metabolite production, and host responses is still required.

Variability in raw materials, influenced by cultivar, maturity stage, and processing conditions, affects pectin, resistant starch, and polyphenol composition and structure, leading to inconsistent functional performance. Advanced processing methods such as enzymatic hydrolysis and purification can improve functional quality, but they often involve higher operational costs and technical complexity.

Regulatory considerations also complicate commercialization: pectin is generally recognized as safe, while emerging derivatives such as pectic oligosaccharides may require additional safety evaluation. More critically, robust human clinical evidence is lacking, because most reported microbiota modulation and short chain fatty acid benefits come from in vitro or animal models.

Dose-response relationships and mechanistic understanding, particularly for fiber-polyphenol interactions, remain incomplete, and increases in beneficial microbes can be overinterpreted without clinical validation. Mango by-products represent a sustainable and multifunctional source of prebiotic ingredients, driven by their combined dietary fiber and polyphenol composition.

Current evidence supports their ability to modulate gut microbiota through mechanisms extending beyond conventional prebiotics. Variability, limited standardization, and insufficient clinical validation constrain the practical application of mango by-products. Integrated advances in processing, mechanistic understanding, and clinical research are required to establish them as reliable next-generation prebiotic ingredients.

Mango by-products combine dietary fiber and polyphenols in a promising, multifunctional prebiotic system. But inconsistent composition, processing trade-offs, and limited human evidence mean the opportunity is promising—not yet proven.