Starch Innovations for Sustainability and Health

As a vital energy reserve in green plants, starch has quietly shaped human civilization—nourishing the body, powering societies, and steering the course of history. In contemporary history, scientists have acquired an in-depth understanding of starch biosynthesis in major starchy crops and leveraged this knowledge to enhance the versatility, affordability, functionality, and nutritional quality of starch through targeted breeding efforts. To further expand its range of applications, chemical, physical, enzymatic, and biological methods have been developed and employed to modify this hydrocolloid over the past century. The implications of global climate change, rising demand for high-quality foods, and increasing consumer awareness of health and well-being have driven recent innovations in starch production, modification, and application.

New Commercial Starch Sources

In the last few decades, targeted breeding programs have been established in the private sector, publicly funded research institutions, and universities to develop new crop varieties with unique starch functional properties. For instance, waxy varieties have been identified or developed in different starchy crops, including maize, cassava, potato, rice, wheat, barley, and sorghum. With exceptionally low amylose content (< 8%), the obtained native waxy starches are valued for their high viscosity upon cooking, clear paste formation, and excellent cold-storage stability (Hsieh et al. 2019). Conversely, high-amylose varieties have been explored or bred in maize, wheat, barley, rice, potato, and pea. These starches, characterized by a high amylose content (exceeding 50%), are known for their substantial resistant starch content and dietary fiber benefits, as well as their requirement for elevated cooking temperatures (> 100°C) to fully manifest functional potential (Li et al. 2019, Liu et al. 2019). High-amylose starches also exhibit excellent film-forming properties, positioning them as a promising, sustainable alternative to petroleum-based plastics.

More recently, the agrifood sector has significantly expanded production of plant-based proteins to meet growing consumer demand. After proteins are extracted from widely used crops such as pulses and oats, their residual starches have emerged as abundant coproducts, presenting new opportunities for further characterization and utilization. To ensure sustainable protein supply chains, effective valorization of these starch coproducts is essential. Additionally, the unpredictability of climate change poses a major threat to the sustainability of starch supply chains. In response, the agrifood industry is increasingly exploring crops with greater resistance and resilience to climate stress, such as sorghum, millet, teff, quinoa, and amaranth, which typically outperform modern, highly bred crops under challenging environmental conditions.

Starch Modification

As a widely available and important hydrocolloid, starch is commonly modified to overcome its inherent limitations, such as high susceptibility to breakdown under shear, heat, and acidic conditions during processing and strong tendency to retrograde during cold storage that causes syneresis. In the industry, the improvement can be achieved through chemical, physical, enzymatic, and biological approaches. Traditional starch modifications have largely relied on chemical methods. Over the decades, various methods have been developed to improve starch functionality for diverse applications, including acid thinning, oxidation, cross-linking, chemical substitution, and grafting with copolymers, each designed to enhance specific performance characteristics.

In recent years, growing concerns over the environmental and health impacts of traditional chemical methods have fostered the development of greener processes, which prioritize the use of more efficient catalysts and nonhazardous chemicals, as well as the reduction of hazardous waste. Aligned with this trend, physical, enzymatic, and biological methods have gained prominence as more sustainable alternatives to conventional chemical modifications of starch. Physical methods employ various physical techniques to alter the structural features and functional attributes of starch, including hydrothermal treatments (e.g., heat-moisture treatment and annealing), extrusion, thermal inhibition, high-pressure processing, ultrasonication, and pulverization (e.g., ball milling and cryogenic milling).

In contrast, enzymatic methods employ specific enzymes to modify starch at both the granular and molecular levels, enabling precise control over its techno-functional properties. Common starch-acting enzymes used for this purpose include α-amylases, β-amylases, debranching enzymes (e.g., pullulanases and isoamylases), branching enzymes, and amylosucrases. Nevertheless, the industry needs to address the persistent challenge of high enzyme costs in starch modification, which remains a key barrier to broader adoption.

Fermentation has been used to convert starch, an abundant and cost-effective feedstock, into higher-value products such as alcohols, rare sugars, sugar alcohols, organic acids, amino acids, and biopolymer monomers [e.g., lactic acid for polylactic acid (PLA), hydroxyalkanoates for polyhydroxyalkanoates (PHAs), and succinic acid for polybutylene succinate (PBS)]. Furthermore, starch can be broken down into its monomer—D-glucose, a vital energy source in pharmaceutical cell culture systems used to produce monoclonal antibodies, vaccines, recombinant proteins, and other biologics. Biological processes also hold significant potential for modifying the granular and molecular structures of starch to achieve desired functional properties.

With rising demand for clean label ingredients that are perceived as natural, simple, minimally processed, and free from chemical additives, the aforementioned physical, enzymatic, and biological methods of starch modification are generally considered acceptable within this framework, despite the term clean label lacking official definition in regulations by agencies such as the U.S. Food and Drug Administration (FDA), the European Food Safety Authority (EFSA), or Codex Alimentarius.

In parallel with the advancements in starch modification methods, analytical techniques for evaluating their effects are also evolving. A notable example is the application of the Rapid Visco Analyser 4800—a viscometer capable of heating starch suspensions up to 140°C—to determine starch pasting and gelation properties under high-temperature, high-pressure cooking conditions as well as to reveal starch molecular interactions after modifications (Cheng et al. 2024, Cheng et al. 2025).

Interestingly, molecular entanglement induced by hydrothermal modifications has been demonstrated to influence the pasting and gelling properties of starch while also reducing its digestibility in humans (Cheng et al. 2025).

Specialized Nutrition

Starch, a major dietary energy source, is hydrolyzed into D-glucose by amylolytic enzymes in the gastrointestinal tract following ingestion. The resulting D-glucose is then absorbed via active transport, providing a critical energy supply for the human body. However, excessive intake of high-glycemic foods in modern diets can lead to significant postprandial glycemic spikes, which are associated with increased risks of type 2 diabetes, obesity, cardiovascular diseases, certain cancers, and other metabolic disorders (Blaak et al. 2012).

Consequently, it is imperative to develop dietary starch with reduced digestibility, which can help mitigate excessive glycemic responses and improve long-term metabolic health. Certain starch ingredients, due to their unique structural characteristics and functional properties, are rich in resistant starch—a starch fraction that escapes digestion in the small intestine and instead reaches the large intestine, where it is (partially) fermented by the gut microflora. Two important examples are high-amylose starch (type 2 resistant starch, RS2) and distarch phosphate (RS4), both of which demonstrate multiple promising physiological benefits in humans and are thus accepted as dietary fiber under the updated FDA definition.

Similarly, starch can be transformed into resistant dextrins through a dextrinization process. Resistant dextrins not only offer various health benefits, but they also possess functional attributes distinctly different from those of resistant starch and soluble dietary fibers (Lefranc-Millot et al. 2009). Resistant dextrins generally exhibit higher water solubility and greater acid and heat resistance than resistant starch, which renders the former particularly well-suited for beverages, dairy products, confectionery, salad dressings, and baked goods.

For specialized nutrition, novel slowly digestible starches, maltodextrins, and oligosaccharides have garnered significant interest because they provide a more consistent and sustained energy release, potentially supporting metabolic health. Nevertheless, incorporating resistant starch and slowly digestible carbohydrates into food systems faces challenges, including inter-individual variability in human metabolism and discrepancies between in vitro and in vivo digestion models (Hasjim et al. 2010, Lin et al. 2012). Furthermore, food processing can notably alter starch digestibility, making it essential to determine the starch digestibility of the final food products.

Nonfood Applications

Due to their abundant supply, exceptional versatility, biocompatibility, and ease of functional modification, starch and its derivatives find broad applications across the pharmaceutical, cosmetic, and other industrial (e.g., bioplastic, paper and board, construction, and textile) sectors. In the pharmaceutical industry, native and modified starches are widely used as excipients, disintegrants, diluents, binders, and coatings. Current research focuses on the design of advanced starch-based systems, including porous starch, microparticles, nanoparticles, and hydro-/cryo-/aerogels for targeted delivery and controlled release of drugs. Starch is being explored as a sustainable biomaterial alternative to synthetic polymers in various biomedical and pharmaceutical applications, including bioscaffolds, capsule shells, enteric coatings, and oral drug delivery systems. Moreover, starch has been used to replace animal-derived gelatin for producing plant-based soft gels and hard capsules, catering to certain religious groups and dietary preferences (e.g., vegetarians and vegans).

Starch and its derivatives are widely used in cosmetic products, including skin care, hair care, oral care, color cosmetics, and fragrances. Native and modified starches can function as effective thickeners, film formers, gelling agents, absorbents, and stabilizers. Sodium starch octenyl succinate with small granule sizes (e.g., from quinoa and amaranth) is a potent emulsifier for Pickering emulsions, commonly used in topical lotions and creams. Moreover, aluminum starch octenyl succinate is an effective anti-caking agent and a suitable alternative to mineral-based powders and talc.

Traditionally, starch has played important roles in several industrial sectors. For example, starch and its derivatives are commonly used as sizing agents, coating agents, adhesives, and binders in the paper and board, textile, and construction industries. With its natural abundance, low cost, biorenewability, biodegradability, and biocompatibility, starch stands out as a promising candidate to replace petroleum-based and synthetic chemicals in performance materials.

As a natural biopolymer, starch can be processed similarly to synthetic polymers to produce thermoplastics. To improve the mechanical properties and water resistance, starch is often blended with other biopolymers, such as PHAs, PLA, and PBS, to develop packaging materials, agricultural mulch, films, disposable cutlery, and other similar products. Starch microparticles and nanoparticles have also been incorporated into conventional plastics as fillers. The incorporation of starch into conventional plastics and bioplastic composites not only reduces production costs, but it also enhances their functionality and overall biodegradability.ft