Functional Clean‐Label Starch: Sustainable Production Technologies and Food Applications

Abstract

Non-conventional and underutilized starch sources: identification, selection, extraction, and characterization. Characteristics and functional properties of starch treated with physical, enzymatic, and other modification methods. Micro/nanoencapsulation properties of starch. Starch for biodegradable films, nanoparticle-based composite films, and their food applications. Nano-sized starch, starch-protein/starch-lipid complexes, and applications. Starch in development of plant-based alternatives and consumer acceptability. For this special issue, global experts were invited to contribute to the afore-mentioned specialized topics on clean-label starch. After a thorough single-blind peer-review process, 27 (21 research + 6 review) articles were selected for final publication. This editorial seeks to highlight key insights and contributions from the collection of 27 articles that investigated diverse aspects of clean-label starch. The exploration of nonconventional and underutilized starch sources presents a significant opportunity to diversify starch availability while promoting sustainability in food production. A study by Flores-Garcia et al.[4] investigated the impact of amylose content on the physicochemical properties of red and white sorghum starches. They observed amylose content ranging from 24.51% to 34.34%, with larger granules having lower amylose. Red sorghum starches exhibited higher gelatinization enthalpy and water absorption due to phenolic complexes. Starches with higher amylose content showed lower viscosity and greater thermal stability, suggesting potential applications. Likewise, another study by Roy and Kumar[5] isolated starch from mankanda tubers using base and acidic methods and evaluated their physicochemical, structural, thermal, rheological, and release profiles. Base-extracted starch yielded 8.14%, and acidic-extracted starch yielded 7.28%, with neutral pH, high water holding capacity, and irregular granules of 1.34–16.12 µm. They displayed type A and B crystal structures, good thermal stability, shear thinning behavior, and potential for colon-targeted sustained release formulations. Another study by Banerjee and Kumar[6] assessed elephant foot yam starch's impact on potato starch in drug delivery applications. Pregelatinization increased amylose content and improved flow properties, disrupting the starch granular structure. Tablets formulated with pregelatinized starches exhibited slower drug release, enhanced by adding potato starch for sustained release profiles. Overall, these studies explored the importance of unconventional starch sources for their functional properties and potential contributions to sustainable food and pharmaceutical industries. Characteristics and functional properties of starch, modified through physical, enzymatic, and other methods, enhance its versatility in food applications. For example, Dorantes-Campuzano et al.[7] explored starch-pectin blends processed via extrusion, highlighting pectin's protective role on starch granules, and altered thermal and pasting properties. Similarly, Singh et al.[8] compared wet milling extraction methods for barnyard millet starch, finding the alkaline method yielded high starch content (64.76%) with good amylose (34.52%) and enhanced functional properties, such as water and oil binding capacities, whiteness, thermal stability (91.62 °C), texture (74.70 g), and reduced particle size (19.44 µm). Using the same physical approach, Phi et al.[9] studied the investigated heat–moisture treatment (HMT) of mung bean flour, showing reduced viscosities and increased resistant starch levels, beneficial for low-carbohydrate foods. A study by Phothisoot et al.[10] applied superheated steam drying to unripe banana flour to enhance resistant starch content and physico-functional properties. Another study by Shivaswamy et al.[11] utilized physical and chemical modifications to mango kernel starch, altering water binding capacity, thermal stability, and retrogradation behavior, enhancing its suitability for food applications. Rathee et al.[12] developed high-fiber bread using whole pearl millet flour (WPMF), whole wheat flour (WWF), and gluten powder (GP). Increasing WPMF levels enhanced firmness, gumminess, chewiness, and color but reduced crumb cohesiveness, resilience, and overall acceptability. The optimized blends of 63.17 g WPMF, 50 g WWF, and 3.92 g GP produced clean label bread with 8.67% fiber and a low glycemic index (33). Collectively these findings demonstrated the versatility and potential of modified starches to meet diverse technological and nutritional demands in the food industry. Micro/nanoencapsulation properties of starch refer to its ability to encapsulate bioactive compounds or ingredients at a micro or nano scale, enhancing stability, controlled release, and bioavailability. Starch, due to its biocompatibility and biodegradability, is used to encapsulate various substances like vitamins, flavors, bioactive compounds, and pharmaceuticals using spray drying, coacervation, and emulsion methods for targeted delivery and sustained release.[13] For example, Marinopoulou et al.[14] utilized a pilot-scale spray dryer to produce starch systems incorporating different starch sources and natural antioxidants. The study exhibited the presence of molecular interactions between starch and antioxidants, endothermic peaks (91–112.1 °C), and uniform distribution of antioxidants within the starch matrix. The powders exhibited low moisture content (<10%), high lightness (L = 90), and yellow color. The study showed the potential of starch-based systems in food and pharmaceutical applications, particularly in enhancing antioxidant stability and functionality. Similarly, two independent studies by Sharma et al.[15] and Sharma et al.[16] investigated loquat seed and faba bean starches in nanoemulsion formulations, respectively. The first study achieved a loquat seed starch yield of 30.04%, developing a stable nanoemulsion with 160.40 nm particle size and −16.20 mV zeta potential, effectively enhancing strawberry preservation by reducing weight loss and altering acidity and soluble solids. The latter study obtained faba bean starch with a yield of 31.20 g 100 g−1, producing an optimized nanoemulsion with 108.62 nm droplet size and −27.74 mV surface charge. Both studies highlighted seed starches’ ability to form stable nanoemulsions, offering the potential for improving food preservation and quality. Recently, starch has received significant interest in the development of biodegradable films and nanoparticle-based composite films due to its renewable and biocompatible nature.[17] Biodegradable starch films offer a sustainable alternative to traditional plastics, enhanced with plasticizers and additives to improve flexibility, strength, and barrier properties against moisture and gases. Nanoparticle-based composite films find applications in food packaging where they can extend shelf-life, maintain food quality, and reduce food waste by protecting against microbial growth and oxidation.[18] Starch-based films and nanoparticle composites contribute to sustainable packaging solutions while meeting regulatory requirements for food contact materials. Independent reviews by Sarma et al.,[19] Naveen and Loganathan,[20] and Paul et al.[21] emphasized fruit and vegetable waste-based starches and starch-PHA blends as sustainable alternatives for biodegradable films, supporting a circular economy by reducing waste. Using potato, cassava, bean, and maize starches, Costa et al.[22] developed water-absorbent aerogels and assessed their properties. Aerogels exhibited low density, high porosity, and good elasticity, with water absorption capacities ranging from 685% to 1714%. Potato and bean starch aerogels maintained stable water retention over 12 uses, while maize starch aerogels effectively absorbed chicken breast exudate. Likewise, Gautam et al.[23] examined the effects of dry heat treatment (DHT) on finger millet starch (FMS) to enhance its suitability for thin films. DHT reduces amylose content, swelling, ash, and moisture, improving FMS solubility. Films made from DHT-treated FMS showed enhanced homogeneity, mechanical strength, water solubility, and vapor permeability. Another study by Kumar et al.[24] investigated the effects of orange peel essential oil and ultrasonic treatment on corn starch-based edible coatings for citrus fruits (Kinnow). Ultrasonication reduces particle size, enhancing stability and antimicrobial properties. The coating formulation improves tensile strength and solubility and extends Kinnow shelf life by reducing weight loss and microbial load and maintaining acidity, soluble solids, and antioxidant activity, highlighting its potential in food preservation. Nazrul et al.[25] developed hybrid nanocomposite films by integrating a starch-co-poly(methyl methacrylate) (St-co-PMMA) copolymeric matrix with Mg-Al layered double hydroxides (LDH) and silver nanoparticles (AgNPs). The addition of LDH and AgNPs enhances oxygen barrier properties by eight-fold and improves chemical resistance. Increasing LDH concentration enhances antibacterial activity. These nanocomposite films demonstrate enhanced thermal stability, chemical resistance, barrier properties, and antibacterial efficacy. In summary, starch-based biodegradable films and nanoparticle composites provide sustainable packaging solutions that inhibit microbial growth and promote a circular economy. Innovations such as water-absorbent aerogels, dry heat-treated starch films, and improved coatings showcase their promise for eco-friendly packaging applications. Nano-sized starch and its complexes represent innovative solutions for enhancing product quality, nutritional value, and functional performance in various applications, reflecting ongoing advancements in starch-based materials science. In this regard, Pumacahua-Ramos et al.[26] explored the physical and thermal properties of Cañihua nano-starch from the Ramis variety. The nano-starch particles displayed a polyhedral shape, with 85% ranging between 712 and 955 nm. Surface-agglomerated nano-starches exhibited low roughness values. The nano-starch demonstrated type A crystallinity (28.52%) and a transmittance ratio of 1.33. Thermal stability reached 251 °C with decomposition peaks at 203, 354, and 512 °C. During pasting, it showed a temperature of 60.2 °C, minimal peak viscosity at 95 °C, and low viscosity breakdown, highlighting its thermal and functional attributes of nano-starch. With a similar approach, Chavan et al.[27] synthesized pearl millet starch nanoparticles using acid hydrolysis and studied their characteristics. The study found that the hydrolysis reduced amylose content, enhancing water and oil absorption capacities and swelling power. Pasting properties were altered, and particle size was reduced. Morphological analysis revealed distinct granule shapes and surfaces with an A-type crystalline structure. These studies highlighted the versatility and potential applications of nano-sized starch and its derivatives in improving food and pharmaceutical formulations. Two recent studies by Chao et al.[28] and Dik et al.[29] exclusively focused on the development of starch-based food products and enzyme immobilization for juice clarification, respectively. Chao et al.[28] explored the impact of starch–lipid complexes (type I and type II) on wheat noodle quality and starch digestibility. Type I complexes increased noodle lightness but raised cooking loss due to gluten disruption, while type II had a lesser effect on texture but improved resistance to amylolysis. In contrast, Dik et al.[29] investigated xylanase (Xyl) immobilization on starch nanoparticles (SNPs), achieving 91% efficiency. The immobilized Xyl@SNPs exhibited enhanced stability, maintaining 62% activity after seven reuses, with improved substrate affinity and successful application in clarifying orange juice, demonstrating a 76% increase in clarity within 2 h. Similarly, Patel, et al.[30] used casein-decorated silica-infused magnetite nanoparticles to immobilize α-amylase. Immobilization enhanced stability and allowed for 17 consecutive cycles with 52% residual activity. The immobilized amylase produced high maltose syrup using industrial wastewater, with dextrose equivalence values of 36% and 24% during cycles 1 and 2, respectively. Overall, the afore-mentioned studies emphasized the diverse applications of nano-sized starch and its derivatives in enhancing food and pharmaceutical formulations. Moreover, starch-based complexes and SNPs as promising tools for improving food quality and enhancing enzyme functionality in industrial applications. Starch plays a crucial role in the burgeoning market of plant-based alternatives by contributing to the sensory attributes and nutritional profiles of these products. As consumer interest in plant-based diets grows, starch serves as a versatile ingredient that aids in mimicking the textures and mouthfeel traditionally associated with animal-derived products like meat and dairy. Moreover, starch offers formulators flexibility in achieving desired textures, from creamy to firm, ensuring a wide range of sensory experiences. Its clean label appeal—being natural and minimally processed—aligns with consumer preferences for healthier, sustainable food choices. In this context, a review conducted by John and Raman[31] emphasized starch interactions with phytochemicals, enhancing the bioavailability and bioaccessibility of these compounds while reducing the glycemic index of plant-based foods. Additionally, Lagunes-Delgado, et al.,[32] highlighted that dual modifications significantly enhance starch functionality and modify its digestibility, critical for innovating products like 3D-printed materials and biodegradable packaging with superior mechanical properties. This strategy also facilitates the development of foods resistant to enzymatic hydrolysis, promising advancements in food technology and sustainable packaging solutions. Overall, the development of starch-based food products using natural, familiar, understandable, and recognizable ingredients is likely to be embraced by consumers in the market. In conclusion, the special issue on clean-label starch has gathered significant insights in advancing starch sustainable production technologies and its diverse applications in the food industry. Through the contributions of global experts, this special issue has illuminated innovative approaches and insights that enhance the functionality, transparency, and eco-friendliness of starch-based ingredients. Moving forward, these advancements promise to reshape food formulations towards greater sustainability, meeting evolving consumer preferences and regulatory standards worldwide. The authors would like to extend their gratitude to all the authors and contributors who have shared their expertise and research findings in this special issue on functional clean-label starch: sustainable production technologies and food applications. This research received no external funding. The authors declare no conflict of interest. Conceptualization, K.S., B.S.I., and M.S.; data curation, K.S., B.S.I., and M.S.; formal analysis, K.S., B.S.I., and M.S.; funding acquisition, M.S. and B.S.I.; investigation, K.S., B.S.I., and M.S.; methodology, K.S. and M.S.; project administration, B.S.I. and M.S.; resources, M.S. and K.S.; software, M.S.; supervision, M.S. and B.S.I.; validation, B.S.I. and M.S.; visualization, B.S.I. and M.S.; writing — original draft preparation, K.S. and M.S.; writing — review and editing, K.S., B.S.I., and M.S.; all authors have read and agreed to the published version of the manuscript. Kandi Sridhar is an Adjunct Assistant Professor at the Department of Food Technology, Karpagam Academy of Higher Education (Deemed to be University), Coimbatore, India. His research focuses on microencapsulation of plant proteins and the development of novel food products. He earned his Ph.D. in Food Chemistry from National Pingtung University of Science and Technology, Taiwan in 2020. Recognized with an outstanding researcher award, his work centers on bioactive molecule identification from food waste, micro/nanoencapsulation, and functional food development. Dr. Sridhar has over 8 years of research experience, publishing extensively, and editing special issues in renowned international journals. Minaxi Sharma, currently an Assistant Professor in Smart Food at Research Center for Life Science and Healthcare, Nottingham Ningbo China Beacons of Excellence Research and Innovation (CBI), University of Nottingham Ningbo China, Ningbo, China, specializes in food processing technologies for functional proteins from plant sources and vegan-based smart foods. With a Ph.D. in Dairy Chemistry from NDRI Karnal, India, she has over 9 years of experience in academia and research. Her expertise includes food waste utilization, probiotics in dairy, and development of functional foods using micro/nano-colloidal delivery systems. She has published extensively, edited special issues in journals, and received the Young Scientist Award. Dr. Sharma is affiliated with international associations and serves as Visiting Assistant Professor at USTM Meghalaya, India and others. Baskaran Stephen Inbaraj is currently working as an Assistant Professor (Teaching) and Senior Researcher in the Department of Food Science, Fu Jen Catholic University, New Taipei City, Taiwan. He holds a Ph.D. in Chemistry from National Institute of Technology Tiruchirappalli, India, with nearly 20 years of research and 7 years of teaching experience in India and Taiwan. He has been rated as the World's Top 2% Scientists by Elsevier/Stanford University (USA) since 2022. His diverse research interests include Nanoscience & Nanotechnology, Nanotherapeutics, Sensors, Food Chemistry, Green & Sustainable Methods, Food/Agricultural/Environmental Waste Valorization, Green Extraction & Pretreatment Techniques, Food/Environmental Toxins–Analysis & Treatment, Chromatography–Method Development, Pharmacokinetics & Bioavailability and Adsorption Science & Technology. He has published over 130 articles in renowned journals, authored 15 book chapters, and delivered 20 conference presentations. Currently, he has an H-index of 40 and a total citation number on his publications of 6334. He holds editorial positions in 7 international journals and reviewer positions in 80 international journals and editing a handful of special issues in renowned journals. The data that support the findings of this study are available from the corresponding author upon reasonable request.

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