Starch granules as active guest molecules or microorganism delivery systems

Starch-guest complexes interactions: Molecular mechanisms, effects on starch and functionality

Starch is a natural, abundant, renewable and biodegradable plant-based polymer that exhibits a variety of functional properties, including the ability to thicken or gel solutions, form films and coatings, and act as encapsulation and delivery vehicles. In this review, we first describe the structure of starch molecules and discuss the mechanisms of their interactions with guest molecules. Then, the effects of starch-guest complexes on gelatinization, retrogradation, rheology and digestion of starch are discussed. Finally, the potential applications of starch-guest complexes in the food industry are highlighted. Starch-guest complexes are formed due to physical forces, especially hydrophobic interactions between non-polar guest molecules and the hydrophobic interiors of amylose helices, as well as hydrogen bonds between some guest molecules and starch. Gelatinization, retrogradation, rheology and digestion of starch-based materials are influenced by complex formation, which has important implications for the utilization of starch as a functional and nutritional ingredient in food products. Controlling these interactions can be used to create novel starch-based food materials with specific functions, such as texture modifiers, delivery systems, edible coatings and films, fat substitutes and blood glucose modulators.

Formation, influencing factors, and applications of internal channels in starch: A review

Starch, a natural polymer, has a complex internal structure. Some starches, such as corn and wheat starches, have well-developed surface pores and internal channels. These channel structures are considered crucial in connecting surface stomata and internal cavities and have adequate space for loading guest molecules. After processing or modification, the starch-containing channel structures can be used for food and drug encapsulation and delivery. This article reviews the formation and determination of starch internal channels, and the influence of different factors (such as starch species and processing conditions) on the channel structure. It also discusses relevant starch preparation methods (physical, chemical, enzymatic, and synergistic), and the encapsulation effect of starch containing internal channels on different substances. In addition, the role of internal channels in regulating the starch digestion rate and other aspects is also discussed here. This review highlights the significant multifunctional applications of starch with a channel structure.

Comparison of in vitro starch digestibility and structure of matcha-fortified starch vermicelli from different botanical sources

BACKGROUND

In a study to explore the utilization of polyphenols in complex digestive systems, starch-based vermicelli was employed as the carrier and matcha (MT) was used as the source of polyphenols. Four percent MT was extruded with A-, B-, and C-type starch of rice, sweet potato, and mung bean to prepared starch vermicelli rice starch vermicelli (RSV), sweet potato starch vermicelli (SPSV), and mung bean starch vermicelli (MBSV), respectively. The multi-scale structure of starch, the digestive kinetics of starch, and the bioaccessibility of polyphenols during in vitro digestion were monitored.

RESULTS

Matcha did not change the crystal configuration of vermicelli, but increased the relative crystallinity of RSV. Vermicelli with MT possessed a more uniform structure, and the polydispersity index decreased from 3.85-4.89 to 2.56-3.69. However, these structural changes made only a limited contribution to delaying digestion. The detection of polyphenols during digestion revealed that the release of most polyphenols was accomplished in the first 20 min of digestion. The release amount was in the order RSV + MT > MBSV + MT > SPSV + MT, and reached 4.81-5.45 mg GAE g-1 . Correspondingly, the activity of digestive enzyme decreased in the order RSV + MT < MBSV + MT < SPSV + MT. Consequently, MT significantly (P < 0.05) reduced the digestive rate of vermicelli, and the rapidly digested starch and predicted glycemic index of RSV + MT decreased from 71.28% to 56.31% and from 74.68 to 62.86, respectively. The released polyphenols were also the main source of the strong antioxidant capacity of vermicelli with MT.

CONCLUSIONS

These results provided a theoretical basis for using polyphenols to pursue healthy starch-based food. © 2023 Society of Chemical Industry.

Exploring the roles of starch for microbial encapsulation through a systematic mapping review

Microorganism encapsulation protects them from stressful conditions and assists in maintaining their viability, being especially beneficial when the carrier material is a renewable and biodegradable biopolymer, such as starch. Here, a systematic mapping was performed to provide a current overview on the use of starch-based systems for microbial encapsulation. Following well-established guidelines, a systematic mapping was conducted and the following could be drawn: 1) there was a significant increase in publications on microbial encapsulation using starch over the past decade, showing interest from the scientific community, 2) ionotropic gelation, emulsification and spray drying are the most commonly used techniques for starch-based microbial encapsulation, and 3) starch play important functions in the encapsulation matrix such as assisting in the survival of the microorganisms. The information gathered in this systematic mapping can be useful to guide researchers and industrial sectors on the development of innovative starch-based systems for microbial encapsulation.

Starches in the encapsulation of plant active ingredients: state of the art and research trends

As a natural polymer, starches and their derivatives have received widespread attention in the cosmetic and pharmaceutical industries, particularly for their use as a coating material. In this sense, as an encapsulating agent, starches stand out, considering the number of compounds that they can trap. Additionally, they provide a nutritional contribution and may improve acceptance by patients. As such, this type of material may serve as an alternative to overcome gaps such as loss of activity of the active principles, low assimilation, or deterioration under environmental and physiological conditions. In this paper, we aim to present the state of the art and research trends on the use of starch as a wall material for the encapsulation of active principles of plant origin. It was found that the most-encapsulated active principles are essential oils and polyphenols; native or modified starches are typically used, either as the sole wall material or in combination with other polymers; and the most widely used methodology is spray drying. The reviewed studies indicate the potential of starches for their use in active ingredient encapsulation processes, improving their viability and expanding their range of applications in different industries, as well as showing a clearly increasing publication trend over the last 10 years.

Graphical abstract

Applications of Biopolymers for Drugs and Probiotics Delivery

Research regarding the use of biopolymers has been of great interest to scientists, the medical community, and the industry especially in recent years. Initially used for food applications, the special properties extended their use to the pharmaceutical and medical industries. The practical applications of natural drug encapsulation materials have emerged as a result of the benefits of the use of biopolymers as edible coatings and films in the food industry. This review highlights the use of polysaccharides in the pharmaceutical industries and as encapsulation materials for controlled drug delivery systems including probiotics, focusing on their development, various applications, and benefits. The paper provides evidence in support of research studying the use of biopolymers in the development of new drug delivery systems, explores the challenges and limitations in integrating polymer-derived materials with product delivery optimization, and examines the host biological/metabolic parameters that can be used in the development of new applications.

Starch-based materials encapsulating food ingredients: Recent advances in fabrication methods and applications

Encapsulation systems have gained significant interest in designing innovative foods, as they allow for the protection and delivery of food ingredients that have health benefits but are unstable during processing, storage and in the upper gastrointestinal tract. Starch is widely available, cheap, biodegradable, edible, and easy to be modified, thus highly suitable for the development of encapsulants. Much efforts have been made to fabricate various types of porous starch and starch particles using different techniques (e.g. enzymatic hydrolysis, aggregation, emulsification, electrohydrodynamic process, supercritical fluid process, and post-processing drying). Such starch-based systems can load, protect, and deliver various food ingredients (e.g. fatty acids, phenolic compounds, carotenoids, flavors, essential oils, irons, vitamins, probiotics, bacteriocins, co-enzymes, and caffeine), exhibiting great potentials in developing foods with tailored flavor, nutrition, sensory properties, and shelf-life. This review surveys recent advances in different aspects of starch-based encapsulation systems including their forms, manufacturing techniques, and applications in foods.

Fabrication of nanostructured mesoporous starch encapsulating soy-derived phytoestrogen (genistein) by well-tuned solvent exchange method

The present research was concerned with preparation of mesoporous starch (MPS) as a carrier for genistein, a model of poorly water-soluble phytoestrogen isoflavone; and exploration of the impact of different fabrication parameters on structural and loading properties. MPS is considered as a highly porous biomaterial which typically possesses nanometer-sized porous microstructure and low density, providing a large effective specific surface area (SSA) and hydrophilic surface to improve solubility, stability and bioavailability of poorly water-soluble active agents. To fabricate MPS, various concentrations (8-14% w/v) of starch from different sources (corn, potato and tapioca) was used for gel formation and the successive solvent exchange process was performed with use of various ethanol concentrations (40-70% v/v), which were then dried by different techniques (rotary vacuum evaporation, microwave and freeze drying). MPS quality attributes such as SSA, total porous volume, BJH pore diameter and swelling ratio were determined and effects of the fabrication parameters were investigated using L9-Taguchi orthogonal array design. The results indicate that second order polynomial regression models were well fitted for all response variables. Interestingly, the starch components greatly influenced physical properties of MPS. Also, the drying type and ethanol concentration altered significantly the model equations. The overall best fabrication condition (14% corn starch, 100% ethanol concentration in aging step and rotary vacuum drying) resulted in favorable MPS preparation with mean size of 105.4 nm and unimodal distribution. In the next step, genistein was encapsulated in MPS microstructure at different ratios, resulting in high loading capacity and efficiency (44.71% and 79.9%, respectively) at 1:1 weight ratio. Equilibrium adsorption isotherm of genistein was evaluated also by four different kinetics models including Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms. The experimental data were found to be fitted well to the Langmuir model (R2 = 0.989). According to the electron microscopy and XRD analysis, the degree of genistein crystallinity lowered remarkably after the impregnation in to MPS, indicating improved solubility. In-vitro release profile of genistein from MPS in the simulated gastrointestinal buffer solutions (pH 1.2 and 6.8) demonstrated that incorporating genistein into the MPS enhanced the dissolution rate compared with genistein powder. Release kinetic data were fitted to the Higuchi model (R2 = 0.98), indicating diffusion-controlled release mechanism. Altogether, well-tuned MPS fabrication method can be utilized for an efficient encapsulation and dissolution enhancement of poorly soluble phytochemicals, such as genistein.

Potential prebiotics and their transmission mechanisms: Recent approaches

Prebiotics are non-digestible carbohydrates which can be used as prime source of energy for gut microflora. These can be naturally occurring in fruit and vegetables or can be made synthetically by enzymatic digestions. New versatile sources of prebiotics had been found nowadays for economic commercialization. This review will decipher on highlighting the importance of prebiotics in immunomodulation and nutrient absorption abilities of gut, as it is important for the anti-effective capacity of the organism especially in the neonatal period. Moreover, new prebiotics transmission strategies with higher penetrating capacity such as microencapsulation and immobilization have been discussed. In addition to this, literature had shown the modulation of gut microflora by the continuous use of prebiotics in many disorders so here, the role of prebiotics in health-related issues such as diabetes and inflammatory bowel disease (IBS) have been explained.