Developments in the isolation, composition, and physicochemical properties of legume starches

Enzymatic Debranching of Starch: Techniques for Improving Drug Delivery and Industrial Applications

Starch is a biomacromolecule comprising glucose units linked together and is one of the most widely sourced biomacromolecules from plants because of its easy availability and versatility. However, high water solubility and rapid degradation restrict the application of starch in some areas, such as drug delivery. This review describes an enzymatic debranching methodology for enhancing the properties of starch and for improving its performance in both drug delivery applications and various industrial uses. Enzymatic debranching, with enzymes such as pullulanase and isoamylase, targets the branching points in starch chain parts. The enzymes cleave the internal covalent bonds within amylopectin branches. The final product of the reaction is a linear short‐chain glucan. As a result of the enzymatic debranching reaction, large changes in digestibility and molecular weight are observed; the degree of branching decreases; the solubility is modified; viscosity characteristics are affected; and gelatinization is also affected. These changes make debranched starch suitable for use in various types of drug delivery systems, such as sustained release formulations and targeted delivery systems. By properly controlling both the debranching time and the treatment conditions, the desired properties of modified starch can be achieved. Enzymatically debranched starch is used in the food industry for enhanced textural and stabilizing properties and in the paper and textile industries to increase strength and viscosity. In addition, debranched starch can be used as a biodegradable packaging material and as a renewable source in biofuels. This review discusses recent developments concerning the enzymatic debranching of starch, describes the enzymes and techniques applied, their effects on the structure and properties of the starch obtained, and the value chain applications tested. This study provides a clear overview of how enzymatically debranched starch can play a role in the innovation of drug delivery systems and various industrial processes.

Formation and crystalline structure of spherulites from pea and high amylose maize starches

Starch spherulite is a unique form of resistant starch characterized by a spherical structure with crystalline lamellae that are radially oriented and may find applications in delivery of nutrients and bioactives to the lower gastrointestinal tract. Formation of starch spherulites generally requires heating to a high temperature followed by quenching and long crystallization time. The objectives of this study were to gain a deeper understanding of the factors influencing spherulite formation from pea starch (PS) and high-amylose maize starch (HAMS) and investigate if spherulites could be formed by a slow cooling rate and determine the crystalline structure and morphology of the spherulites formed. Remarkably, spherulite was observed immediately after PS and HAMS (25 % solids) were heated to 180 °C and cooled to 10 °C at a cooling rate of 10 °C/min in a differential scanning calorimeter (DSC) pan. Increasing heating temperature degraded starches more but improved the morphological quality of spherulites. Spherulite was better formed at 25 % solids content than 40 %. Both PS and HAMS formed spherulites with a predominant B-type crystalline pattern with 13-17 % crystallinity at ca. 10 % moisture content. PS displayed a single exothermic peak on cooling due to spherulite formation (recrystallization), whereas HAMS exhibited an extra peak due to the amylose-lipid complex formation. Spherulite production from HAMS and PS was successfully scaled up using a pressure reactor. This study provides a simplified approach for spherulite production, new potential utilization of PS and HAMS, and valuable insights for optimizing formation of starch spherulites.

High temperature and humidity storage alter starch properties of faba (Vicia faba) and adzuki beans (Vigna angularis) associated with hard-to-cook quality

Hard-to-cook (HTC) beans are characterised by extended cooking times. Although the changes in cell walls limiting hydration in HTC beans are widely investigated, the role of macro-molecules (starch and protein, which constitute >80 % of beans) are almost overlooked. This study investigates the structural changes in starch associated with the HTC quality in faba and adzuki beans stored at contrasting temperature and humidity regimes. Beans were stored at 4 °C (control) and 40 °C with relative humidity (RH) levels of 60 % and 80 %. Significant changes in starch properties were observed, particularly in beans stored at 40 °C and 80 % RH, with swelling power decreasing by 7 % and 12 % for faba and adzuki beans, respectively. Additionally, gelatinisation behaviour was negatively affected, with peak temperatures increasing for adzuki beans (from 66.64 °C to 68.46 °C) and enthalpy rising for faba beans (from 9.25 J/g to 10.64 J/g) along with an increase in relative crystallinity. Overall findings indicate that storage at elevated temperature (40 °C) under both moderate and high humidity conditions (60 % and 80 %) primarily or partially leads to developing HTC beans due to molecular rearrangement of starch at helical and crystalline levels.

A review of the effects of physical processing techniques on the characteristics of legume starches and their application in low-glycemic index foods

Physical processing techniques significantly influence the characteristics of legume starch, consequently affecting the potential applications of legume-based products. This review comprehensively examines the impact of various physical processing techniques on legume starch properties, including structure, granule morphology, gelatinization, pasting properties, solubility, and in vitro digestibility. Furthermore, it evaluates the implications of these processing methods for utilizing legumes in developing low-glycemic index (GI) foods. Notably, certain physical processing methods, such as heat-moisture treatment, ultrahigh-pressure processing, dry heat treatment, and gamma irradiation, under specific conditions, enhance the resistant starch or slowly digestible starch fractions in legume starches. This enhancement is particularly advantageous for producing low-GI foods. Conversely, techniques like annealing, extrusion, ultrasound, and germination increase starch digestibility, which is less favorable for low-GI food applications. This review also provides an up-to-date overview of the use of diverse preprocessed legume products in low-GI food production. The novelty of this review lies in its detailed comparative analysis of physical processing methods and their specific effects on legume starch digestibility, which has not been extensively covered in existing literature. The comprehensive insights presented herein will benefit the legume industry by informing effective strategies for converting legume starch into valuable low-GI products.

The Physicochemical Properties and Structure of Mung Bean Starch Fermented by Lactobacillus plantarum

Understanding the relationship between gel formation and the hierarchical structure of mung bean starch fermented by Lactobacillus plantarum has potential value for its green modification and quality improvement. The variations in characteristics, including gelation characteristics, starch chain, and the molecular order degree of mung bean starch fermented by different L. plantarum, were compared. The results show that in the gelation process, starch began to disintegrate at 65 °C, indicating a critical temperature for structural changes. Compared with the control group, although the effects of different L. plantarum sources on mung bean starch varied, notable improvements were observed in water absorption across all groups of fermented starch, along with reduced free water-soluble substances and enhanced anti-expansion ability. This led to the easier formation of gels with higher viscosity, primarily attributed to decreased crystallinity, increased short-chain amylopectin tendency, an elevated amylose content, and enhanced short-range order when microorganisms acted on the crystallization zone. In conclusion, although L. plantarum came from different sources, its action mode on mung bean starch was similar, which could enhance the gel structure.

Optimisation of dry heat treatment conditions for modification of faba bean (Vicia faba L.) starch

Faba bean is a protein-rich starchy grain that is underutilised in the UK. The starch of faba bean can be modified using environmentally friendly methods like dry heat treatment (DHT) to enhance functional and its physicochemical properties. This study investigated the impact of dry heat temperature and time on the structure, functional and physicochemical properties of faba bean starch (FBS) using a two-factor central composite rotatable design. Factors (DHT temperature:100-150 °C and DHT time:0.5-5 h) with their respective α mid-point values led to 13 experimental runs. Selected pasting and functional properties were measured as response variables. Corn starch was included as a reference and compared with the FBS modified using the optimized conditions. DHT increased peak (approx. 2205-2267 cP), final (approx. 3525-3642 cP) and setback (approx. 1887-1993 cP) viscosities but decreased the amylose content of FBS. Colour, as measured by lightness value, morphology and crystalline type were not altered but the starches showed a loss of order and an increase in crystallinity after DHT. FBS appeared resilient to DHT but showed higher swelling power and pasting properties compared to the corn starch control. The optimum DHT conditions to produce starch with desirable properties are a temperature of 100 °C for 0.1716 h, with a desirability factor of 66 %.

Unlocking the Nutraceutical Potential of Legumes and Their By-Products: Paving the Way for the Circular Economy in the Agri-Food Industry

Legumes, including beans, peas, chickpeas, and lentils, are cultivated worldwide and serve as important components of a balanced and nutritious diet. Each legume variety contains unique levels of protein, starch, fiber, lipids, minerals, and vitamins, with potential applications in various industries. By-products such as hulls, rich in bioactive compounds, offer promise for value-added utilization and health-focused product development. Various extraction methods are employed to enhance protein extraction rates from legume by-products, finding applications in various foods such as meat analogs, breads, and desserts. Moreover, essential fatty acids, carotenoids, tocols, and polyphenols are abundant in several residual fractions from legumes. These bioactive classes are linked to reduced incidence of cardiovascular diseases, chronic inflammation, some cancers, obesity, and type 2 diabetes, among other relevant health conditions. The present contribution provides a comprehensive review of the nutritional and bioactive composition of major legumes and their by-products. Additionally, the bioaccessibility and bioavailability aspects of legume consumption, as well as in vitro and in vivo evidence of their health effects are addressed.

The effect of heat moisture treatment times on physicochemical and digestibility properties of adzuki bean, pea, and white kidney bean flours and starches

The effects of heat moisture treatment (HMT) times on the physicochemical properties of three bean flours and their starch were analyzed. The colors of L*, b* and ΔE values increased significantly with time. The adzuki bean and pea flours showed better WAI and SP, and better gelation of starch at 2 h. The rheological properties of mixed HMT dough (3:7) exhibited the typical solid-like weak gel behavior. HMT had a significantly decreased on the pasting viscosity of bean flour starch with treated time. HMT caused the starch granules damage, but did not radically change the crystal type. FTIR results showed more proteins attached to the surface of starch granules, and the short-range molecular order decreased the DO at 2 h. In vitro digestibility inferred that RDS converted into SDS and RS. These results indicated that HMT significantly affected the digestibility and physicochemical properties of bean flours.

Starch from Unripe Apples (Malus domestica Borkh) as an Alternative for Application in the Food Industry

This study investigated the properties of starch isolated from the unripe fruit of two apple cultivars (Malus domestica Borkh) grown in southern Poland (Central Europe). The chemical composition of both starches, molecular mass, their granulation, thermal characteristics, swelling characteristics, and rheological characteristics were studied. The starches differed significantly in ash, phosphorus, and protein content. The water-binding capacity at temperatures of 25-65 °C was similar, while differences of 20% appeared at higher temperatures. In contrast, a significant difference was found in the solubility of the two starches in the temperature range of 25-75 °C. The study showed that apple starches have a relatively low tendency to retrograde, with the enthalpy of gelatinization for starch from the Oliwka variety being 40% higher than that from the Pyros variety. However, the starches differed in the hardness of the gels formed, i.e., one variety formed soft gels with an internal structure resistant to external forces, while the other formed hard gels.

The Iodine/Iodide/Starch Supramolecular Complex

The nature of the blue color in the iodine-starch reaction (or, in most cases, iodine-iodide-starch reaction, i.e., I2 as well as I- are typically present) has for decades elicited debate. The intensity of the color suggests a clear charge-transfer nature of the band at ~600 nm, and there is consensus regarding the fact that the hydrophobic interior of the amylose helix is the location where iodine binds. Three types of possible sources of charge transfer have been proposed: (1) chains of neutral I2 molecules, (2) chains of poly-iodine anions (complicated by the complex speciation of the I2-I- mixture), or (3) mixtures of I2 molecules and iodide or polyiodide anions. An extended literature review of the topic is provided here. According to the most recent data, the best candidate for the "blue complex" is an I2-I5--I2 unit, which is expected to occur in a repetitive manner inside the amylose helix.

A Comprehensive Review of Pea (Pisum sativum L.): Chemical Composition, Processing, Health Benefits, and Food Applications

Pisum sativum L., commonly referred to as dry, green, or field pea, is one of the most common legumes that is popular and economically important. Due to its richness in a variety of nutritional and bioactive ingredients, the consumption of pea has been suggested to be associated with a wide range of health benefits, and there has been increasing focus on its potential as a functional food. However, there have been limited literature reviews concerning the bioactive compounds, health-promoting effects, and potential applications of pea up to now. This review, therefore, summarizes the literature from the last ten years regarding the chemical composition, physicochemical properties, processing, health benefits, and potential applications of pea. Whole peas are rich in macronutrients, including proteins, starches, dietary fiber, and non-starch polysaccharides. In addition, polyphenols, especially flavonoids and phenolic acids, are important bioactive ingredients that are mainly distributed in the pea coats. Anti-nutritional factors, such as phytic acid, lectin, and trypsin inhibitors, may hinder nutrient absorption. Whole pea seeds can be processed by different techniques such as drying, milling, soaking, and cooking to improve their functional properties. In addition, physicochemical and functional properties of pea starches and pea proteins can be improved by chemical, physical, enzymatic, and combined modification methods. Owing to the multiple bioactive ingredients in peas, the pea and its products exhibit various health benefits, such as antioxidant, anti-inflammatory, antimicrobial, anti-renal fibrosis, and regulation of metabolic syndrome effects. Peas have been processed into various products such as pea beverages, germinated pea products, pea flour-incorporated products, pea-based meat alternatives, and encapsulation and packing materials. Furthermore, recommendations are also provided on how to better utilize peas to promote their development as a sustainable and functional grain. Pea and its components can be further developed into more valuable and nutritious products.

The structure-glycemic index relationship of Chinese yam (Dioscorea opposita Thunb.) starch

Yam (Dioscorea opposita Thunb.) is an important functional food in Asia. Yam starch usually has a low glycemic index. What is the structure requirement of starch to obtain a low glycemic index remains unknown. In order to understand the structure-glycemic index relationship, six yam starches from various regions with apparent structure difference were analyzed. Chinese yam starch (CYS) showed the lowest glycemic index. It presented as oval or round granules. Meanwhile, CYS showed a distinct A-type crystal structure while the others presented C-type crystal structure. The largest crystallinity, R_w, M_w/M_n, RS level, RS + SDS level, and the lowest peak viscosity, trough viscosity and C_∞ values were found for CYS. These data explained the lowest glycemic index of CYS. The above results suggested that CYS was a good neutraceutical candidate and could be used in the diet of diabetes population.

Salt Solubilization Coupled with Membrane Filtration-Impact on the Structure/Function of Chickpea Compared to Pea Protein

The demand for pulse proteins as alternatives to soy protein has been steeply increasing over the past decade. However, the relatively inferior functionality compared to soy protein is hindering the expanded use of pulse proteins, namely pea and chickpea protein, in various applications. Harsh extraction and processing conditions adversely impact the functional performance of pea and chickpea protein. Therefore, a mild protein extraction method involving salt extraction coupled with ultrafiltration (SE-UF) was evaluated for the production of chickpea protein isolate (ChPI). The produced ChPI was compared to pea protein isolate (PPI) produced following the same extraction method in terms of functionality and feasibility of scaling. Scaled-up (SU) ChPI and PPI were produced under industrially relevant settings and evaluated in comparison to commercial pea, soy, and chickpea protein ingredients. Controlled scaled-up production of the isolates resulted in mild changes in protein structural characteristics and comparable or improved functional properties. Partial denaturation, modest polymerization, and increased surface hydrophobicity were observed in SU ChPI and PPI compared to the benchtop counterparts. The unique structural characteristics of SU ChPI, including its ratio of surface hydrophobicity and charge, contributed to superior solubility at both a neutral and acidic pH compared to both commercial soy protein and pea protein isolates (cSPI and cPPI) and significantly outperformed cPPI in terms of gel strength. These findings demonstrated both the promising scalability of SE-UF and the potential of ChPI as a functional plant protein ingredient.

Non-conventional starches isolated from agronomic-improved beans (Phaseolus vulgaris L.): a study of their structure and physicochemical properties

BACKGROUND

Non-conventional starch sources are promising alternative food ingredients. Different bean varieties with agronomic improvements are constantly being developed and cultivated in the Northwestern Argentinean region (NOA) to increase yields and obtain high-quality seeds. However, the main attributes of their starches have not been studied. In this work, starches from four agronomic-improved bean cultivars were isolated and their structure and physicochemical properties were evaluated.

RESULTS

High-purity starches were obtained, as shown by their low protein and ash content. Starch granules presented smooth surfaces with spherical to oval shapes, with a marked 'Maltese cross' and heterogeneous sizes. Their amylose content revealed a mean value of 318 g kg^-1 and all presented resistant > slowly digestible > rapidly digestible starch fractions. Their Fourier transform infrared spectra were similar and X-ray diffraction analysis showed a C_A -type pattern in all cases despite their different sources. Among thermal properties, Escarlata starch showed the lowest gelatinization peak temperature (69.5 °C) and Anahí starch the highest (71.3 °C). Starch pasting temperature varied from 74.6 to 76.9 °C, whereas peak viscosity and final viscosity showed a similar tendency, with Leales B30 < Anahí < Escarlata < Cegro 99/11-2 and Leales B30 < Anahí = Escarlata < Cegro 99/11-2, respectively.

CONCLUSION

This study provides the basis for a better understanding of the characteristics of agronomic-improved NOA bean starches, enabling their use in product formulation as an alternative to starches from conventional sources. © 2023 Society of Chemical Industry.

Effect of Storage Time and Temperature on Digestibility, Thermal, and Rheological Properties of Retrograded Rice

Retrogradation is defined as the recrystallization or realignment of amylose and amylopectin chains upon cooling of gelatinization starch gels. The storage conditions such as the storage time and temperature are crucial factors that influence and govern the degree of retrogradation and in turn, affect the formation of resistant starch and alteration of thermal and rheological properties. This article investigates the effect of storage time and temperature on the properties of retrograded rice starch. Rice kernels of five different indigenous varieties, namely Diasang lahi, Khaju lahi, Dhusuri bao, Omkar, and Bili rajamudi were cooked by boiling in water and stored at 4 °C and -20 °C for 6 and 12 h, respectively. Differential scanning calorimetry (DSC) studies revealed in raw form that Bili rajamudi exhibited the highest peak gelatinization temperature (T_p, °C) at 79.05 °C whereas Diasang lahi showed the least T_p at 56.12 °C. Further, it was indicated that the T_p and degree of retrogradation (DR%) also increase with increasing time and decreasing temperature of storage. All samples stored at -20 °C for 12 h exhibited the highest degree of retrogradation DR%. Amongst all five varieties stored at -20 °C for 12 h, Omkar exhibited the highest %DR, followed by Bili rajamudi, Khaju lahi, Dhusuri bao, and Diasang lahi. A negative correlation was also established between T_p and resistant starch content (RS%). It was also observed that the resistant starch (RS%) content increased with the increasing time and decreasing temperature of storage. A strong negative correlation was observed between RS% and non-resistant starch (NRS%). Further, rheological studies indicated that retrogradation also affects the viscosity and dynamic rheological properties of starch. In this study, it was evident that extending storage duration from 6 to 12 h and lowering temperature from 4 to -20 °C impact retrogradation of rice starch, which in turn affects the starch's gelatinization, digestibility, and rheology. Rice starch retrograded at lower temperatures for a longer period could prove to be extremely beneficial for development of food products with better textural properties and high RS content or low glycemic index.

Optimization of Concentration-Time, Agar, and Sugar Concentration for Sweet Gelatinized Adzuki-Bean Jelly Cake (Yokan) by Response Surface Methodology

Samples of sweet gelatinized adzuki-bean jelly cake were successfully prepared and systematically analyzed to investigate the factors that affect the production, quality, and gelatin properties of yokan (gelatinized adzuki bean cake). The purpose of this study was to investigate the properties of gelatinized adzuki-bean cake gelatin and identify the optimal production conditions using response surface methodology with three factors: agar concentration, sugar concentration, and concentration time. Findings show that the optimum processing conditions are 1.2-1.5% agar concentration and 34-40% sugar concentration, with 30-40 min concentration time. These conditions produced a gelatinized adzuki-bean cake favored by the majority of the sensory evaluators. Overall, the relationships between different gelatinized adzuki-bean cake processing conditions and gelatin properties were preliminarily clarified. The findings not only provide a promising avenue for gelatinized adzuki-bean cake production but also promote the potential application of various processing conditions in quality improvement.

Vegan Egg: A Future-Proof Food Ingredient?

Vegan eggs are designed with the aim to provide a healthier and more sustainable alternative to regular eggs. The major drivers of this industry are the increasing prevalence of egg allergies, awareness towards environmental sustainability, and the shift to vegan diets. This study intends to discuss, for the first time, the vegan egg market, including their formulation, nutritional aspects, and some applications (i.e., mayonnaise and bakery products). Recreating the complete functionality of eggs using plant-based ingredients is very challenging due to the complexity of eggs. Current, but scarce, research in this field is focused on making mixtures of plant-based ingredients to fit specific food formulations. Nutritionally, providing vegan eggs with similar or higher nutritional value to that of eggs can be of relevance to attract health-conscious consumers. Claims such as clean labels, natural, vegan, animal-free, gluten-free, and/or cholesterol-free can further boost the position of vegan eggs in the market in the coming year. At present, this market is still in its infancy stages, and clear regulations of labeling, safety, and risk assessment are deemed mandatory to organize the sector, and protect consumers.

Extraction and characterization of starch from Yard-long bean (Vigna unguiculata (L.) Walp. ssp. unguiculata cv.-gr. sesquipedalis)

Vigna unguiculata subsp. sesquipedalis is an important derivative cultivar of cowpea planted widely in China, and popularly known as "Yard-long bean". There is lack of research about the structural characterization and physicochemical aspects of carbohydrate content in Yard-long bean seeds. Thus, the present study aimed to evaluate structures, thermal and technological properties of Yard-long bean seeds starch (YSS). The starch contains little of ash, protein and total fiber meanwhile amylose content of 37.52%. The shapes of the starch granules obtained from field emission scanning electron microscopy (FESEM) were oval to semi-elliptical with little granules occurring in agglomerated structures clusters, and volume median diameter of granules ranged from 10.5 μm to 12.5 μm. The initial gelatinization temperature of YSS was 73.86 °C, peak temperature was 80.59 °C and final 88.53 °C. Solubility index (SI, 3.43% at 90 °C) and swelling power (SP, 6.62 g/g at 90 °C) were observed with low volume, which corroborated with the C-type structure shown by X-ray diffraction (XRD) and high crystallinity degree. The extraction of YSS can be feasible, and it has suitable properties for use in the food industry.