Cacao in the Circular Economy: A Review on Innovations from Its By-Products

Abstract

Cacao is a food of global interest. Currently, the industry primarily utilizes the seed, which represents between 21% and 23% of the total fruit weight. In 2023, global production reached 5.6 million tons of fermented dry cacao beans, while approximately 25.45 million tons corresponded to cacao residues. The objective of this review was to compile and analyze alternatives for the utilization of cacao by-products. The methodology involved technological surveillance conducted in specialized databases between 2015 and 2025. Metadata were analyzed using VOSviewer software version 1.6.20. Priority was given to the most recent publications in high-impact indexed journals. Additionally, 284 patent documents were identified, from which 15 were selected for in-depth analysis. The reviewed articles and patents revealed a wide range of industrial applications for cacao by-products. Technologies including ultrasonic and microwave-assisted extraction, phenolic microencapsulation, cellulose nanocrystal isolation and targeted microbial fermentations maximize the recovery of polyphenols and antioxidants, optimize the production of high-value bioproducts such as citric acid and ethanol, and yield biodegradable precursors for packaging and bioplastics. The valorization of lignocellulosic by-products reduces pollutant discharge and waste management costs, enhances economic viability across the cacao value chain, and broadens functional applications in the food industry. Moreover, these integrated processes underpin circular economy frameworks by converting residues into feedstocks, thereby promoting sustainable development in producer communities and mitigating environmental impact. Collectively, they constitute a robust platform for the comprehensive utilization of cacao residues, fully aligned with bioeconomy objectives and responsible resource stewardship.

1. Introduction

The inadequate management of agro-industrial waste represents a significant global environmental challenge due to its potential to cause pollution and deplete essential natural resources [1]. In the case of cacao, by-products such as the pod husk, mucilage, and bean shell comprise approximately 76% of the total fruit mass. The improper handling of these residues contributes to ecosystem degradation, the loss of biodiversity, and the disruption of livelihoods in rural communities that depend on cacao production [2]. In producing regions such as Colombia, the empirical use of cacao pod husks (CPHs) as organic fertilizer is widespread. However, excessive accumulation of these residues in the soil can disrupt agroecosystem balance and promote phytosanitary issues, including the proliferation of pests such as the cacao pod borer (CPB) [3]. Furthermore, inadequate disposal practices (such as open dumping or incineration) intensify the environmental pollution of soil, water, and air, thereby exacerbating the impacts of climate change [4].

Although several technological pathways have been proposed for the valorization of cacao by-products, the implementation of these strategies remains limited by barriers such as lack of technical knowledge, insufficient training, and restricted access to appropriate infrastructure in cacao-producing communities. These challenges are further compounded by social, economic, technological, and environmental constraints, often in the absence of robust institutional support [5]. In response, emerging technologies present promising avenues for the efficient and sustainable conversion of cacao lignocellulosic biomass. Methods such as ultrasound-assisted extraction, microwave processing, ionic liquids, deep eutectic solvents, enzymatic hydrolysis, hydrothermal treatment, high-voltage electrical discharge, and pyrolysis have demonstrated efficacy in recovering bioactive compounds and reducing inorganic contaminants, such as cadmium [6].

The integration of conventional techniques (acid-base extraction and fermentation) with emerging technologies has been shown to optimize yields, enhance the quality of extracted bio-compounds, and expand the range of industrial applications across the food, pharmaceutical, energy, agricultural, and materials sectors [7]. Addressing the issue of cacao waste management within a circular economy framework reduces the environmental footprint of cacao production while simultaneously creating opportunities for value-added product development, capacity building, rural entrepreneurship, and the advancement of more resilient and sustainable production systems.

The majority of waste generated along the cacao production chain originates at the farm level. However, the processing industry also contributes significantly, particularly through the generation of cacao bean shell as a by-product. According to FAOSTAT [8], global cacao processing in 2023 yielded approximately 5.6 million tonnes of dry, fermented beans. This figure represents only the marketable portion of the fruit, which accounts for approximately 23.2% of its total weight [9]. Based on these data, the estimated total production of whole cacao fruit reaches around 24.13 million tonnes. From this biomass, only the nibs are destined primarily for chocolate manufacturing, whereas the remaining fractions are classified as agro-industrial residues: cacao pod husk (67% of the fruit’s weight, equivalent to ~16.37 million tonnes), mucilage (9%, ~2.20 million tonnes), and cacao bean shell (2%, ~0.48 million tonnes) [10] (Figure 1). The valorization of these by-products presents a significant opportunity to reduce the environmental burden of the cacao industry and to support the development of high value-added products with functional and economic potential.

This review aims to provide a comprehensive analysis of emerging technologies and strategies for the valorization of cacao by-products. It outlines their chemical composition, recent advances in extraction and transformation processes, current industrial applications, and the key challenges hindering their effective implementation.

Cacao fruit is composed of approximately 67% pod husk (CPH), 9% mucilage, 23–25% beans (including nibs and shells), and a small proportion of placenta [11,12]. The outer husk is particularly rich in cellulose, hemicellulose, lignin, and phenolic compounds; the mucilage contains sugars, organic acids, and polyphenols, while the cacao bean shell (CBS) is a valuable source of dietary fiber, proteins, and minerals [13].

Recent studies have focused on unlocking the potential of these co-products through various valorization pathways. For example, Valadez-Carmona et al. demonstrated that microwave and freeze-drying methods effectively preserve the structural integrity, phenolic content, and antioxidant activity of cacao pod husk [14]. Efforts by Neto et al., along with the commercial initiatives KOA Pure^® and Oabika^®, have highlighted the feasibility of transforming cacao mucilage into functional beverages through pasteurization, emphasizing its potential as a health-promoting ingredient [15]. Additionally, Campos-Vega et al. investigated the incorporation of cacao bean shell into fiber-enriched food formulations [9].

Emerging technologies have also contributed significantly to this field. Ramos-Escudero et al. optimized ultrasound-assisted extraction for recovering bioactive compounds from CPH, achieving high yields of polyphenols and antioxidants under controlled conditions [16]. Nguyen et al. advanced the encapsulation of CPH extracts using maltodextrin, gum arabic, and chitosan matrices to enhance their stability in functional food systems [17]. Dewan et al. reported the successful production of cellulose nanocrystals from cacao husk, with promising applications in biodegradable packaging and advanced biomaterials [12].

Industrial applications have further expanded to include citric acid production through cacao husk fermentation [18], and fungal protein generation using Pleurotus salmoneostramineus cultivated on fermented husk [19]. Chochkov et al. demonstrated that combining cacao husk and Rosa damascena extracts could prolong the shelf life of baked goods [20]. Moreover, Nguyen et al. developed polyphenol-enriched jams by partially substituting mango pulp with cacao husk pulp [21].

Despite these advancements, several barriers remain to be addressed. These include the lack of standardized raw material specifications, the high implementation costs of advanced technologies, compositional variability related to the genetic and geographical origin of cacao, and regulatory constraints such as cadmium content limits [13]. Promoting the integral valorization of cacao by-products has the potential to reduce environmental burdens and diversify industrial value chains. Furthermore, it could foster innovation and the growth of local enterprises, offering new economic opportunities for small-scale cacao producers and contributing to the social and economic development of cacao-growing regions.

2. Methodology

A systematic literature review was conducted to identify, select, and analyze scientific and technological developments related to the valorization of cacao by-products, with a particular emphasis on their applications in the food industry. The review process was carried out manually by the research team and followed the PRISMA methodological framework (Figure 2) [22]. The initial search covered the period from 2015 to 2025 and included peer-reviewed articles, white papers, technical reports, news sources, and patents. The search strategy employed relevant keywords (“cacao waste,” “food,” “shell,” “mucilage,” “cacao,” “residues,” and “cob”) in combination with Boolean operators across specialized databases including ScienceDirect, Scielo, ProQuest, TradeMap, FAOstats, DialNet, Google Patents, and Derwent Innovation.

All retrieved records were screened using a set of predefined inclusion criteria: an explicit focus on the recovery, reuse, or transformation of cacao residues; publication within the defined time frame; and compliance with established standards of scientific rigor. Preference was given to recent publications in high-impact indexed journals, as well as those demonstrating strong bibliometric performance (citation frequency within scientific databases). No automated tools were used during the initial screening phase. The selected literature was organized and managed using Mendeley (version 2.132.2) reference manager, resulting in the inclusion of 90 scientific publications deemed relevant to the study.

To identify conceptual patterns and emerging thematic clusters, metadata from the selected records were filtered based on a minimum threshold of 10 keyword co-occurrences. These were then used to generate co-occurrence networks, which were visualized and analyzed using VOSviewer software (version 1.6.20). This approach facilitated the identification of high-frequency terms and interrelationships within the literature, enhancing the understanding of research priorities and technological focuses within the field.

In parallel, patent analysis was conducted using Derwent Innovation and Google Patents, yielding 284 patent documents. These were reviewed individually to assess their relevance, novelty, and technological alignment with cacao by-product valorization, particularly in the food sector. Following this critical evaluation, 15 patents were selected for detailed analysis.

3. Results and Discussion

The cacao fruit. Cacao is a tropical fruit from an evergreen tree native to the subtropical regions of the American continent. Cacao production is a fundamental economic activity for many farming families. Among the most significant cacao fruit residues is the cacao husk, which accounts for between 67% and 76% of the total waste generated (Figure 3). Other by-products include mucilage and kernel husk, which constitute approximately 8.7–9.9% and 2.1–2.3% of the weight of a fresh pod, respectively [23]. Under traditional processing conditions, mucilage is separated as an exudate before fermentation, while the remainder remains attached to the beans [24]. Mucilage, cacao bean husk, and pod husk all have promising applications, particularly in the extraction of polyphenols with antioxidant properties [25,26].

However, the management of cacao by-products is challenging. In countries like Colombia, producers discard cacao pod husks in the field, where they decompose and serve as organic fertilizer for the same crop. This practice poses a phytosanitary risk, promoting the spread of crop diseases. Additionality, a large portion of this by-product is discarded directly into the environment, contributing to pollution and the waste of a resource with potential applications in the food and biotechnology industries. On the other hand, the mucilage released during fermentation is collected to produce sweets, food for household consumption, or animal feed. Figure 4 illustrates the cacao-processing methods used by small-scale producers in the department of Córdoba, Colombia.

At the industrial level, most of the waste generated in the cacao industry originates in the field. A significant amount of waste is also produced during processing, although in smaller proportions, as in the case of grain husks. Although only the seed is economically utilized (representing between 21% and 23% of the fruit’s weight) [9], the valorization of these by-products could reduce environmental impact and promote the development of high-value-added products with functional benefits. For example, some countries have shown interest in importing cacao residues, classified under tariff heading 180200, which includes cacao husks and other by-products for transformation into ingredients for the food industry and other sectors. In 2023, these imports reached 71.2 thousand tons, valued at 27.9 million dollars. The main importers were France (22%), Belgium (15%), the Netherlands (14%), Brazil (11%), and China (8%), highlighting the growing interest in the reuse and revaluation of this waste within the circular economy model [27].

Use of cacao residues. The analysis of the metadata enabled the visualization of a bibliometric network, illustrating how, since 2023, the circular economy has been consolidated as a central axis of research on cacao utilization [28]. This concept is closely linked to the study of bioactive compounds, bioeconomy, sustainable development, antioxidants, agro-industrial waste, lignocellulosic biomass, and biofuels [29] (Figure 5).

The advances of the circular economy in the cacao chain reflects current research efforts to minimize the loss of products with industrial potential. This approach addresses the growing concern over global environmental issues, positioning itself as a priority on the world’s scientific and political agenda [30]. The need to transform traditional production models has driven the search for strategies that maximize resource utilization throughout the production matrix [31]. Although the waste-generation figures may be alarming, cacao by-products such as the pod, husk, and mucilage contain compounds that make them viable for technological applications and alternative uses [32,33,34,35].

Studies on cacao by-products have shown that they are rich in lignin, pectin, cellulose, hemicellulose, protein, and natural fiber [36]. These components can be utilized as substrates for fermentation processes [37] or for the extraction of stabilizing compounds [38]. Additionally, cacao holds global significance due to its multiple health benefits. It is a natural source of antioxidants and bioactive compounds with high pharmaceutical relevance [39]. Among its diverse phenolic compounds, the most notable are theobromine, catechin, and epicatechin, which have been studied for their potential effects on colon cancer [40], skin cancer, and anemia [41].

Cob from cacao fruit. The cacao fruit pod (CPH) is the largest component of the fruit, accounting for approximately 67–76% of its total weight [42]. Typically, the cacao pod is considered a non-usable agro-industrial waste. However, it contains bioactive compounds of interest, making its valorization a relevant research area [37]. The cacao pod is rich in fibrous materials, including 19.7–26.1% cellulose, 8.7–12.8% hemicellulose, 14–28% lignin, and 6.0–12.6% pectin. The epicarp is enriched with lignin, while the mesocarp consists mainly of cellulose (~50%), and the endocarp is rich in pectic substances [43]. These characteristics have driven the food industry to explore the potential applications of these compounds, which possess functional properties that can enhance the quality and sustainability of food products [44].

Pectin is widely used in the food industry as a gelling, thickening, and stabilizing agent [45]. It is commonly employed in the production of jams, jellies, gummies, and dairy products due to its ability to form gels in the presence of acid and sugar. Several studies have explored the extraction of pectin from agricultural by-products such as CPH. The pectin obtained from these residues exhibits antioxidant properties. According to a study conducted by Anoraga et al., pectin extracted from CPH has been identified as low-methoxyl pectin, with a degree of esterification of approximately 26.8% [33]. In addition, CPH pectin exhibits relevant functional properties for pharmaceutical and nutraceutical applications due to its pseudoplastic behavior, high swelling capacity, and antibacterial activity. Pectin has demonstrated effectiveness against both Gram-positive and Gram-negative bacteria, particularly Escherichia coli. These bioactive characteristics position CPH pectin as a versatile pharmaceutical excipient and a promising natural antimicrobial agent for the development of new food and medicinal products [33].

Lignin is a complex polymer found in plant cell walls and has traditionally been considered an undesirable by-product in the pulp and paper industry. However, recent research has explored its potential applications in the food industry due to its antioxidant, antimicrobial, and antibacterial properties [46]. Studies suggest that lignin could function as a natural preservative in food products. Additionally, lignin-based biodegradable packaging materials could contribute to reducing the use of conventional plastics [47]. Advances in lignin extraction and processing, particularly from CPH, have transformed this substance into a valuable resource for producing functional foods and enhancing the sustainability of the food industry [48].

Hemicellulose is a polysaccharide that contributes to plant structure and rigidity [49]. In the food industry, it is primarily used as a source of dietary fiber. Incorporating hemicellulose into baked goods, such as bread and cookies, improves water retention, thereby enhancing product texture [50]. Recent studies have shown that hemicellulose extracted from agricultural residues exhibits techno-functional properties that enhance both the quality and nutritional value of food products. However, its recovery typically requires advanced extraction techniques (such as thermal hydrolysis or solid-state fermentation) which are associated with high costs, operational complexity, and difficulties related to the heterogeneous nature of biomass waste. Despite these challenges, the implementation of sustainable and efficient technological solutions remains essential for transforming these by-products into value-added ingredients for the agri-food industry [51].

Finally, cellulose is the most abundant natural polymer in plants and has multiple applications in the food industry. Its primary uses include serving as a bulking agent and stabilizer, as well as being incorporated into dietary fiber formulations, particularly in weight-loss products and foods designed to support digestive health [52]. Cellulose extracted from cacao by-products can be integrated into processed food products to provide additional functional benefits, such as enhancing satiety and regulating intestinal transit. Moreover, recent research suggests that cellulose can be used to create edible films that extend the shelf life of food, offering a sustainable alternative to traditional plastic packaging [53].

In the food sector, the use of cacao pod husk (CPH) enriched with soluble dietary fiber (SDF) has demonstrated nutritional benefits, including enhanced fiber intake, increased satiety, and reduced glucose absorption. Trials incorporating CPH into baked goods such as bread and muffins have shown that it can partially replace fats, improving moisture retention and texture. Nevertheless, sensory challenges such as bitterness, stickiness, and reduced loaf volume persist [43]. Additionally, CPH has emerged as a promising raw material for the extraction of cellulose nanocrystals (CNCs), typically obtained through acid hydrolysis and bleaching treatments. CNCs exhibit significant application potential across the pharmaceutical, paper, photonics, and composite materials industries, owing to their outstanding mechanical, thermal, and barrier properties [11]. Nevertheless, large-scale industrial implementation still faces challenges, including high processing costs and the need to improve the functional properties of the resulting packaging materials, underscoring the necessity for further research to optimize these applications [12].

Another emerging trend in the use of CPH is the extraction of phenolic compounds with antioxidant properties for application in food products [54,55]. To achieve this, these compounds must be extracted using organic solvents diluted in water, employing techniques such as ultrasound, microwaves, or supercritical fluids. These methods facilitate the rupture of plant cell walls within the matrix, allowing for the release of bioactive compounds [55].

Regarding the extraction of antioxidant compounds, Dewi et al. evaluated the effect of solvent type and particle size on the phenolic extraction of cacao pod shells [56]. Microwave-assisted extraction demonstrated a higher potential for obtaining bioactive compounds due to its volumetric and selective heating capabilities. The authors also analyzed other extraction parameters, such as time, temperature, and ethanol concentration, which significantly influenced phenolic compound yields and functionality. The highest bioactive yields were recorded at 50 °C with a 5 min extraction time, obtaining anthocyanin levels of 0.37 ± 0.0 mg GE/g and an antioxidant capacity of 3.36 ± 0.02 mg TE/g [56].

Campos-Verga et al. analyzed various extraction processes to valorize CPH and optimize the production of bio-composites [9]. Their study evaluated multiple extraction methods, highlighting the significant influence of CPH powder concentration and extraction time on process efficiency. Metabolic analysis identified 124 compounds, including tartaric acid, gluconic acid, and various bioactive agents with antioxidant properties, leading to a high total phenolic content of 3.88 ± 0.06 mg/g. Additionally, pectin extracted through alkaline and enzymatic methods exhibited comparable performance to commercial pectin and superior antioxidant capacity [9].

Recent investigations have highlighted the substantial potential of cacao pod husk (CPH) as a source of bioactive compounds and as a raw material for the development of innovative industrial applications. Valadez-Carmona et al. systematically evaluated the impact of different drying methodologies (microwave, hot air, and freeze drying) on the preservation of phenolic compounds, antioxidant capacity, enzymatic activity, and structural integrity of CPH. Their findings demonstrated that microwave and freeze-drying techniques more effectively retained matrix integrity and functional bioactivity, suggesting that the choice of post-harvest processing method is critical for maximizing the functional value of CPH-derived ingredients [14].

Ramos-Escudero et al. employed ultrasound-assisted extraction coupled with response surface methodology (Box–Behnken design) to optimize the recovery of bioactive constituents from CPH. Extracts obtained under optimized conditions exhibited notably high levels of total phenolic content (48 mg GAE/g), TEAC (0.30 mmol TE/g), FRAP (0.35 mmol FeSO₄/g), and ORAC (0.43 mmol TE/g). Moreover, LC-ESI-qTOF-MS analysis enabled the identification of 40 distinct bioactive compounds, further substantiating the efficacy of sonoextraction as a rapid and robust strategy for high-value compound recovery from CPH and cacao bean shells (CBS) [16].

Concurrently, emerging valorization approaches such as the microencapsulation of bioactive extracts have garnered increasing attention. As Mehta et al. observed, microencapsulation not only enhances the stability and protection of sensitive bioactives but also enables controlled release profiles during digestion, thereby broadening their applicability in functional food systems [57]. In line with this, Nguyen et al. successfully developed alkaloid-rich microencapsulated powders from CPH, utilizing encapsulating agents such as maltodextrin, gum arabic, and chitosan, highlighting the potential for these technologies to integrate cacao-derived bioactives into next-generation functional food formulations [17].

Emerging applications also include the production of citric acid through solid-state fermentation using cacao pod husk (CPH) as a substrate. de Oliveira et al. confirmed the value of cacao pods as an alternative source for industrial bioconversion processes, emphasizing their viability as an economical and sustainable substrate [18]. Similarly, Chochkov et al. investigated the combined use of Rosa damascena by-products and cacao husks as natural preservatives in muffins [20]. The addition of extracts obtained via supercritical CO₂ extraction extended the shelf life of baked goods up to 20 days, attributed to their antioxidant and antimicrobial properties.

In another study, Bickel Haase et al. employed Pleurotus salmoneo-stramineus to ferment cacao pod husk flour (CPHF) in order to obtain protein- and fiber-rich food ingredients. The results demonstrated that basidiomycete fungi could successfully grow on CPHF, producing high-quality protein with an improved amino acid profile when cacao husk was used as the primary substrate. Nonetheless, process optimization remains necessary for industrial-scale application [19].

Furthermore, Nguyen et al. explored the valorization of CPH as a substitute for mango pulp in jam production. Two replacement levels (25% and 50%), with and without commercial pectin addition, were evaluated. The results showed that jams enriched with cacao pulp exhibited a 3- to 3.9-fold increase in phenolic content and a 1.5-fold improvement in DPPH antioxidant activity. Moreover, CPH-enriched formulations demonstrated better retention of phenolic compounds during storage, although minor changes in texture and flavor were noted by sensory panels [21].

Collectively, these studies highlight the significant potential of cacao residues as raw materials for the development of food, pharmaceutical, and sustainable packaging products. Beyond offering agricultural valorization pathways, cacao waste streams are also driving technological innovation in extraction, encapsulation, and bioconversion processes, contributing to the advancement of a more circular and responsible industry model [58].

These approaches for quantifying functional compounds have been complemented by technologies for developing food additives (powders or encapsulates) that can be incorporated into food matrices. Microencapsulation is considered one of the most effective strategies for utilizing functional compounds, as it enhances the protection and controlled release of bioactive compounds during digestion [57].

Patent analysis reveals that countries such as the United States, Canada, India, Australia, China, Brazil, and Japan have developed innovations related to the production of CPH-derived powder products. These inventions (WO2022031596-A1; US2022039446-A1; CA3179012-A1; IN202347005327-A; AU2021320634-A1; CN115802906-A; BR112023001518-A2; EP4192269-A1; JP2023533287-W) focus on applications in food products such as confectionery, baked goods, fillings, spreads, and beverages. The manufacturing process involves wet grinding followed by drying at temperatures above 80 °C, ensuring a moisture content of ≤12.5% w/w and water activity ≤ 0.4 to minimize microbial growth risk. The final product is notable for its high insoluble dietary fiber content (≥55% w/w) and total dietary fiber (≥68% w/w), with low levels of ash (≤6% w/w) and total sugars (≤8% w/w). Additionally, it has a reduced fat (≤2% w/w) and protein (≤10% w/w) content, expanding its applicability in various food formulations [59].

From a functional perspective, this powder serves as a gelling, thickening, and bulking agent, and can also act as a substitute for egg solids in the food industry. Its low ash content facilitates its integration into a wide range of products without compromising taste or texture. Given its abundance and cost-effectiveness, large-scale production represents a sustainable alternative aligned with the principles of the circular economy, promoting the comprehensive utilization of cacao shells [59].

Meanwhile, the ID202105032-A1 patent focuses on the development of a functional beverage enriched with pectin and citric acid extracted from cacao pods. The production process involves chopping, drying, and grinding the cacao shell, followed by extraction with oxalic acid to obtain pectin. Additionally, cacao pod juice is fermented to generate citric acid. The functional components obtained are then combined to formulate a bioactive-rich beverage. The final composition of this beverage includes 500 mL of extracted pectin, 500 g of sweetened condensed milk, 85.6 g of sucrose, 100 g of palm fruit as a source of galactomannan oligosaccharides, 15 g of cacao powder, 15 g of caramel powder, 1 g of citric acid, 2–5 drops of chocolate flavoring, and 750–1000 mL of water. This innovation transforms cacao shell waste into a valuable source of functional ingredients for the development of nutritionally enhanced beverages.

Mucilage. Mucilage is another agro-industrial by-product generated during cacao processing, specifically during bean extraction prior to fermentation. This mucilage is the fleshy layer that surrounds the cacao bean and is rich in sugars, proteins, fiber, and phenolic compounds. It accounts for approximately 9% of the total cacao fruit and is separated before the fermentation process [42].

The physicochemical characteristics and composition of cacao mucilage, as described in the literature, indicate that it is particularly rich in carbohydrates and total sugars. It also contains essential minerals such as aluminum (Al), barium (Ba), calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), phosphorus (P), potassium (K), selenium (Se), sodium (Na), and zinc (Zn). Additionally, it has a low ash content (~0.2%) and a minimal fat profile (<3.54% lipids) [27].

The primary carbohydrates found in cacao mucilage include glucose (2.13–21.4%), fructose (1.06–4.42%), and sucrose (2.13–4.06%). These sugars are crucial for determining optimal processing conditions, such as temperature control during heat treatments and fermentation, as well as for ensuring product quality and detecting potential adulterations [27].

Guirlanda reported the detailed composition of cacao mucilage, highlighting its high moisture content (86.38 ± 0.09%), which significantly affects shelf life and necessitates immediate processing [27]. The nutritional analysis revealed a high carbohydrate concentration (19.50 ± 1.2%), with a soluble solids content of 17.00 ± 0.01 °Brix and total sugars of 18.00 ± 0.05%, giving it a naturally sweet taste suitable for use in natural sweetener formulations and fermented products. It also has a low protein content (0.62 ± 0.17%) and total fat (1.45 ± 0.2%), along with a moderate fiber concentration (0.80 ± 0.50%) and a low ash content (0.36 ± 0.05%), indicating a limited mineral presence. The high acidity (8.33 ± 0.60) and a pH of 3.50 ± 0.01 position it as a potential ingredient in functional drinks and controlled fermentations. Furthermore, the pectin content (0.51 ± 0.01%) highlights its applicability in the production of natural gelling agents and food stabilizers (

Table 1. Research on the use of cacao mucilage in products with industrial potential in the last 5 years.

Compound	Study	Conclusion	Reference
Obtaining alcohol by Pichia kudriavzevii	Fermentation of sugars using Pichia kudriavzevii to obtain ethanol (13.8 g/L)	Cacao mucilage can be an economical and viable source for ethanol.	[60]
Obtaining cacao honey powder by spray drying for use as a sweetener	An exploratory study of spray-drying technology to obtain cacao honey powder. Drying conditions were evaluated using the same temperature and flow parameters, with variation in maltodextrin, methocel, and whey protein in the formulations with cacao mucilage.	Several formulations were made with maltodextrin plus whey protein isolate. The 29:1 formulation of maldodextrin and whey protein showed better retention of antioxidant compounds relative to the other formulations. The application of non-thermal technologies and the production of cacao honey powder with added protein are shown as potential innovations for cacao cultivation and the food industry.	[27]
Obtaining bacterial cellulose from cacao mucilage	An evaluation of the potential of cacao mucilage (CME) as a carbon source for the production of bacterial cellulose (BC) in a static fermentation process using the bacterial strain Gluconacetobacter xylinus (ATCC®23768™).	High sugar content, low pH of cacao mucilage, and limited sources of nitrogen affect BC yields by hindering the growth of G. xylinus. Even so, this process becomes an alternative to take advantage of the waste in the production of bacterial cellulose (BC), taking into account that this agro-industrial waste is rich in nutrients.	[61]
Extraction and characterization of cacao mucilage and application in the production of food and biopolymers	Methods of extracting cacao mucilage, along with physical and chemical properties, such as its sugar content and phenolic compounds, were investigated. Applications in the food industry, such as sweetener and biopolymer production, were evaluated.	Cacao mucilage has the potential to be used in food and biodegradable packaging, contributing to sustainability and waste reduction.	[62]

).

Recent studies on the use of cacao mucilage have explored its application in the development of kombucha. Rodríguez-Castro et al. evaluated and harvested two cacao varieties, Cacao Nacional Fino de Aroma (NCFA) and Colección Castro Naranjal 51 (CCN-51) [63]. Using these raw materials, they developed a prototype of a fermented beverage with varying mucilage concentrations (40, 60, 80, and 100 g/L), simulating the traditional kombucha fermentation process.

Among cacao by-products, mucilage has the highest number of patents identified in this review. Most of these patents utilize mucilage for the production of syrups with a high solids content. The innovations analyzed primarily focus on its application in confectionery, beverages, ice creams, jams, and chocolate-based products (

Table 2. Patents on the use of cacao mucilage in products with industrial potential in the last 5 years.

Patent Number	Country/Institution	Patent Information	Reference
BE1027939-B1	Belgium	Production of cacao pulp used in confectionery products such as beverages, ice cream, jams, or chocolate products.	[64]
BE1027944-B1	Belgium	Production of pasteurized cacao fruit-juice concentrate used in confectionery products such as beverages, ice cream, jams, or chocolate products. It involves the pre-processing of cacao material by selecting cacao pods.	[64]
EP3777550-A1	European Patent Office	It describes an optimized method for obtaining a sugary substance from cacao mucilage and its application in the production of chocolate and confectionery products.	[65]
EP3824738-A1	European Patent Office	It presents an innovative method for the production of confectionery products from a composition derived from cacao pulp, using an enzymatic treatment with pectinase.	[66]
WO2021026089-A2; WO2021026089-A3; AU2020324404-A1; CN114206122-A; EP4007498-A2; BR112022002010-A2; US2022279807-A1; EP4007498-A4	European Patent Office; Austria; China; World Intellectual Property Organization (WIPO); Brazil; United States	The development of a new food ingredient based on dried cacao pulp, highlighting its application in products such as dark chocolate, chewing gum, fat-free candies, and ice cream.	[67]
BR102019025711-A2	European Patent Office	It describes an innovative method for obtaining cacao pulp powder by means of a drying process, with application in the food, cosmetic, and pharmaceutical industries.	[68]
EP3837989-A1	European Patent Office	It describes a method for the production of confectionery products, particularly chocolate, using cacao pulp with an enzymatic treatment, for the reduction of polysaccharide content.	[69]

).

Patents BE1027944-B1, BE1027939-B1, and EP3824738-A1 describe an optimized method for cacao pulp production through enzymatic treatment. This process reduces the amount of insoluble and water-soluble fiber, improving the fluidity and stability of the product. The pulp undergoes centrifugation to remove unwanted particles and is then concentrated by evaporation until it reaches a soluble solids content of 50–70 °Brix. To ensure consistency and quality, the concentrated product is cooled, packaged under aseptic conditions, and stored at controlled freezing temperatures between 0 and −30 °C, preserving its organoleptic and nutritional properties [64,66].

Patent EP3777550-A focuses on optimizing a sugary substance derived from cacao mucilage through the development of specialized mechanical equipment. This device efficiently collects leachate generated during the fermentation of cacao beans—capturing, filtering, and concentrating the exuded liquid. The system prevents the loss of sugary compounds, ensuring their utilization in the formulation of natural cacao sweeteners [65].

The process begins with the extraction of pulp-coated cacao beans, which are stacked under controlled conditions to initiate natural fermentation. The pressure exerted by the upper layers causes the release of a sugar- and bioactive compound-rich liquid. This leachate is captured by the machine and subjected to filtration and purification to remove suspended particles and undesirable acids. To prevent unwanted fermentation, the collected liquid is processed within six hours of extraction. It is then pasteurized and clarified to stabilize its composition and enhance its sensory profile. Finally, the leachate undergoes evaporation, reducing its water content to obtain a syrup with a total sugar concentration of 60–70% by weight [65].

Patents WO2021026089-A2, WO2021026089-A3, AU2020324404-A1, CN114206122-A, EP4007498-A2, BR112022002010-A2, US2022279807-A1, and EP4007498-A4 focus on the development of a new food ingredient. The method involves subjecting cacao pulp to a spray-drying process, where it is combined with cacao powder, cacao butter, or milk powder to enhance its stability and functionality. This technique enables the production of a natural ingredient free from added sugars, preserving the bioactive compounds of cacao pulp while improving the sensory and nutritional profile of confectionery products [67].

The spray-drying process is carried out at an inlet temperature of 120–180 °C and an outlet temperature of 60–100 °C inside a dryer with a polytetrafluoroethylene (PTFE) coating, ensuring the quality of the final product. The resulting dried cacao pulp can partially or fully replace added sugars in milk chocolates, white chocolates, and coatings. Additionally, it reduces the need for gelatin and starches in confectionery products. In specific applications, it is possible to formulate sweets with up to 70% dried cacao pulp [67].

On the other hand, the BR102019025711-A2 patent describes a method for obtaining cacao mucilage powder through a foam-layer drying process. This technique preserves the bioactive compounds of cacao pulp, extending its shelf life and facilitating its storage and transport [68]. Meanwhile, EP3837989-A1 presents an innovative approach for confectionery production, employing an enzymatic treatment of cacao pulp to reduce polysaccharide content. This process enhances the functionality of the pulp by increasing the concentration of monosaccharides, disaccharides, and oligosaccharides, optimizing its application in food formulations.

The ID202103014-U1 invention features a functional beverage formulation that combines cacao pulp extract, cinnamon extract, and a sugar solution, enhancing both its sensory profile and physiological benefits. The inclusion of fermented cacao pulp juice promotes the generation of bioactive compounds with antioxidant and prebiotic properties. Additionally, other inventions (MX414165-B) describe optimized methods for producing a distillate from cacao mucilage. The process involves material adaptation to ensure a sugar content of 12–23 °Brix, a pH between 3.5 and 5, and freezing at −18 °C. Fermentation begins with the addition of 0.5 g/L of Saccharomyces cerevisiae and occurs at temperatures between 12–28 °C under controlled aeration for 150–288 h. The process concludes with an aging period of 15–50 days to refine its aromatic profile. The resulting distillate has an alcohol content of 30–40% and exhibits a fruity sensory profile.

Cacao bean shell. The cacao bean shell (CBS) is another by-product generated during the chocolate-making process, obtained after the roasting of cacao beans. CBS is typically separated using particle-size sorting or pneumatic systems. According to Cinar et al., the cacao bean husk is rich in dietary fiber and exhibits anti-inflammatory, antioxidant, antiviral, and anti-obesity properties [70]. It also contains polyphenols, lignin, cellulose, and hemicellulose, making it a valuable raw material for various industrial applications [71].

In the food industry, CBS is incorporated into products such as breads, biscuits, and energy bars, while antioxidant extracts derived from CBS are utilized in beverages and nutritional supplements. In the pharmaceutical and cosmetic industries, the phenolic compounds extracted from CBS are valued for their antioxidant and anti-inflammatory properties, allowing for their inclusion in creams and skincare formulations [72].

Studies on CBS have highlighted its high dietary fiber content (18.3–59% of dry matter) and rich phenolic composition [73,74]. According to the Codex Alimentarius, dietary fiber consists of carbohydrate polymers that are indigestible in the human intestine, traditionally classified as soluble and insoluble fractions. However, recent research has emphasized the distinction between fermentable and non-fermentable fibers, given their differential effects on gut microbiota. In this context, CBSs stand out for their ability to modulate microbial communities, particularly by promoting the production of short-chain fatty acids (SCFAs), which play a crucial role in intestinal health [74].

Disca et al. conducted a study aimed at improving the fermentation of CBS through enzyme treatments, assessing their impact on both the proximal and distal regions of the colon [74]. The CBSs were treated with enzyme mixtures, particularly cellulases, to enhance the proportion of fermentable fiber. The results revealed significant SCFA production in both colon regions, demonstrating that enzymatic treatment optimizes the prebiotic potential of CBSs, supporting gut health.

Beyond the food and health sectors, CBSs are also being explored for biofuel and biodegradable material production, leveraging their lignin and cellulose content. These properties contribute to the development of bioplastics and bioethanol. Additionally, CBSs are utilized in animal feed and composting, demonstrating their potential to be converted into valuable resources that drive industrial innovation and environmental sustainability [75].

Table 3. Research on the use of cacao bean husks in products with industrial potential in the last 5 years.

Compound	Study	Conclusion	Reference
CBS flour as an input in the production of bakery products	An evaluation of the use of CBS flour in the production of biscuits as a source of dietary fiber and antioxidant phenolic compounds.	CBS is an alternative for the addition of antioxidant and fiber compounds. In addition, cacao bean husk flour represents a good source of protein and can be used in food-processing processes.	[76]
Phenolic compounds of an antioxidant nature	Microwave-assisted extraction and bromatological characterization of phenolic compounds of antioxidant character in the CBS.	CBS represents a good source of antioxidant compounds and alternates proteins.	[77]
Phenolic compounds of antioxidant character in and microencapsulation	The extraction of phenolic compounds and microencapsulation, using maltodextrin/dextrose. The final product was added in dark chocolate bars.	The microencapsulated product from CBS added to dark chocolate bars enhanced the functional value.	[78]
CBS flour as a substitute for conventional bakery flour	The use of CBS flour as a substitute for conventional baker’s flour. Positive results were obtained in terms of sensory acceptance in mixtures with up to 75% CBS in the total mixture for the production of chocolate cakes.	CBS flour as a component of replacement of common flour and use of nutritional intake. It also provides phenolic compounds of an antioxidant nature.	[36]

summarizes recent research on the industrial applications of CBS over the last five years.

Recent research by Straka et al. explored the use of cacao bean shell (CBS) in beer production [79]. In this study, different concentrations of CBS powder (2%, 4%, 6%, 8%, 10%, and 20%) were incorporated into ground malt for wort preparation. Additionally, a control variant without CBS was included for comparison. Throughout the process, key parameters such as color, density, viscosity, antioxidant activity, total polyphenol content, and nitrogen/protein concentration of the wort were analyzed. The results demonstrated that the addition of CBS significantly increased antioxidant activity and total polyphenol content without notably affecting protein concentration. However, negative effects on density and viscosity were observed, which could influence its applicability in the production of fermented beverages.

The patents analyzed on CBS utilization in the food industry highlight key innovations in various technological and sustainable applications.

Table 4. Patents on the use of CBS in products with industrial potential in the last 5 years.

Patent Number	Countries	Patent Description	Reference
BR102020003432-A2	Brazil	The development of a process for obtaining nanocellulose without chemical or enzymatic pretreatments, in which bioactive compounds are preserved.	[80]
BE1027918-B1	Belgium	The development of a gelled pasta intended as a filling or topping in pastry products.	[81]
PL441732-A1	Poland	It describes a product designed as a combustible material.	[82]
ES2985020-A1	Spain	It describes a method for the production of functional beverages, probiotic beverages, and condiments from CBS.	[83]

provides a summary of patents related to the industrial applications of CBS over the past five years.

One of the patents consulted has high potential in the manufacture of biodegradable packaging, based on the development of nanofibrils derived from cacao bean shell (CBS) (BR102020003432-A2). These nanofibrils can also be used as a polymeric matrix in construction, agriculture, pharmaceuticals, and the paper industry, contributing to the sustainability of industrial materials [80].

Other patents focus on the formulation of gelled pastes for use as fillings or coatings in pastry and confectionery products (BE1027918-B1). This invention incorporates CBS as a functional ingredient, combined with sugars (5.0–70.0% w/w), pectin (0.10–4.0% w/w), texturizers (0.10–7.0% w/w), citrate ions (0.030–3.0% w/w), calcium ions (0.0010–0.50% w/w), preservatives (0.0–2.0% w/w), and water to reach 100% w/w. The composition is highly stable, with a Brix of 45–75 and a pH of 2.8–4.5, ensuring its integration into food products without compromising texture. The high fiber and natural antioxidant content enhances the nutritional profile of the final product. The manufacturing process involves the controlled mixing of ingredients to achieve optimal gelation, ensuring the structural integrity and functionality of the product [81].

In addition, the development of biofuels from CBS represents a significant advancement in renewable energy generation (PL441732-A1). The production process involves mixing cacao shells (30–90% by weight) with a hydrophobic binder (10–70%) and a natural solid flammable substance (up to 50%), followed by prolonged pressing, which enhances stability and energy efficiency. This biofuel offers an eco-friendly alternative to traditional fuels, promoting the reuse of agro-industrial waste and its conversion into sustainable energy sources [82].

Another notable application involves the production of functional beverages and condiments from CBS (ES2985020-A1). The extraction process enables the recovery of antioxidant compounds, particularly polyphenols, using an efficient and scalable method without the need for organic solvents. The technique consists of mixing CBS with water at a weight–volume ratio of 12–20, under temperatures of 20–150 °C, pH between 2 and 10, and a pressure of 0–50 atm for 1–30 min. These controlled conditions facilitate hydrolysis and the release of bioactive compounds, yielding a polyphenol-rich supernatant (1–10 g/L). The resulting functional beverage provides a healthier alternative, while the process also enables the production of vinegars and other condiments, aligning with the circular economy model and expanding applications in the food and pharmaceutical industries [83].

Commercial applications of cacao by-products. Currently, a variety of cacao residue-derived products are commercially available in international markets, particularly in industrialized countries. Figure 6 illustrates examples such as Oabika cacao juice concentrate from Valrhona, derived from cacao mucilage and characterized by a fruity and acidic aromatic profile, recommended for high-end gastronomic applications.

Koa Pure cacao juice, a pasteurized, additive-free product sourced from smallholder farms in Ghana, is marketed at approximately EUR 12.4 per kilogram. Kumasi, a sparkling beverage produced from cacao pulp, is sold at around EUR 13.6 per liter, contributing to a 30% increase in income for participating farmers. Additionally, MÜCILAGE freeze-dried cacao mucilage is available at a premium price of EUR 204.6 per kilogram, attributed to its high concentration and quality. Lastly, fresh cacao bean shells are marketed for use in foods and beverages, with prices ranging from EUR 31.2 to EUR 57 per kilogram, recognized for their nutritional value and applications in baking, infusions, and food decoration [84,85,86,87,88,89,90].

These products reflect the added value that cacao residues can achieve, highlighting both the growing interest of companies and the increasing consumer demand for sustainable, functional, and high-quality products. The international market thus represents a strategic opportunity to stimulate investment in the valorization of cacao by-products, promoting the development of new ventures and industries grounded in the principles of the circular economy.

In countries such as Colombia, where cacao is a strategic agro-industrial commodity, large-scale initiatives for cacao residue transformation remain limited. However, the emergence of projects such as Nextcoa demonstrates the potential to develop new products within cacao value chains, enhancing farmers’ incomes and boosting the food, cosmetic, pharmaceutical, and biodegradable materials sectors [40]. The valorization of cacao residues not only contributes to environmental sustainability but also represents a powerful driver of technological, social, and economic innovation, aligning with the Sustainable Development Goals (SDGs) and global trends in bioeconomy and the comprehensive utilization of natural resources.

Constraints to cacao by-product utilization. A critical challenge for the integral valorization of cacao residues lies in overcoming existing limitations. In Colombia, producer associations have pointed out the need to strengthen knowledge regarding legal and administrative regulations, as well as to enhance organizational and financial management capacities. Moreover, cacao producers often lack the necessary skills for the development and commercialization of value-added products. The absence of strong social organization and clearly defined marketing strategies significantly limits these communities’ access to profitable markets.

In this context, institutions must design and implement educational, technical, and commercial strategies tailored to local realities in order to strengthen the organizational and productive capacities of smallholder farmers. Adopting a comprehensive and context-specific approach could facilitate an effective transition toward inclusive circular economy models, thereby promoting sustainable economic development and increasing the resilience of rural communities. It is crucial for farmers to understand the procedures required to ensure the quality and safety of by-products, particularly through the proper handling of sugar-rich mucilage and antioxidant-rich cacao husks, in order to guarantee their suitability for industrial applications. Furthermore, a comprehensive assessment of local advantages and limitations is necessary to support the sustainable development of these initiatives.

Additionally, regulations concerning the presence of contaminants such as cadmium (Cd) must be carefully considered when valorizing cacao residues. Currently, frameworks such as Regulation (EU) No 488/2014 establish maximum permissible levels of Cd in cacao-derived products: 0.10 mg/kg for chocolate with less than 30% cacao solids, 0.30 mg/kg for chocolate with less than 50%, 0.80 mg/kg for chocolate with 50% or more cacao solids, and 0.60 mg/kg for cacao powder sold directly to consumers [91].

However, in the studies reviewed, the authors did not consider cadmium (Cd) limits for cacao by-products such as mucilage, bean shell, or pod husk. In light of recent biotechnological advances, governmental institutions should incorporate detection limits for Cd in cacao fruit into regulatory frameworks. This necessity arises mainly from the bioaccumulation of Cd in cacao beans, pods, mucilage, and shells, as the metal is absorbed from the soil and accumulates across all plant tissues. Nevertheless, various studies have demonstrated that Cd concentration in cacao varies depending on the cultivation region, agricultural practices, and processing methods employed.

4. Conclusions

This review provides an updated overview of strategies for the valorization of cacao by-products, encompassing their composition, emerging industrial applications, and technological advancements. The articles and patents reviewed highlight the wide range of industrial applications for cacao by-products. Cacao residue valorization has progressed substantially through the development of innovative processes (fermentation for ethanol and functional beverages; the spray drying and microencapsulation of mucilage; and the extraction of pectin, cellulose, lignin, and hemicellulose) yielding natural sweeteners, high-value biopolymers, antioxidant compounds, and bioplastics for the food and pharmaceutical industries. The demand for these by-products, especially in Europe, underscores their economic and strategic potential to improve profitability and the socio-economic conditions of smallholder producers. However, technical and regulatory challenges remain, including the lack of raw-material standardization, the absence of legal frameworks, and the high costs associated with the extraction, stabilization, and purification of bioactive compounds. Consequently, further optimization and adoption of sustainable technologies, comprehensive toxicological evaluations, and detailed economic analyses are required. Such efforts could facilitate the uptake of cacao by-products, strengthen the competitiveness of the cacao sector, and promote environmentally friendly strategies.