Surface modifications of starch provide benefits in various applications for food and medical products as a carrier material due to their high adsorption ability. The effect of enzymatic and acid ...modification of starch surfaces on the morphology and characteristics of granular tapioca starch is investigated. Tapioca starch slurry is prepared and treated with α‐amylase (αA), amyloglucosidase (AM), the combination of these two enzymes (αA+AM), and 2.2 m HCl (AS) at various hydrolysis times. Starch granular surface of αA, AM, and αA+AM‐treated samples show voids and cavities. The AS sample induced more surface roughness in the granules as compared to the enzyme‐treated samples and some parts of the granules are smaller or fused together into a larger size. The highest relative crystallinity is obtained from the AS samples (48.43%). All modified samples exhibit an increase in their specific surface area, volume of pores, and average diameter. The AM sample shows the highest specific surface area (1.66 m2 g−1) which corresponds to the largest pore volume (0.38 cm3 g−1) while the AS sample shows the highest average diameter (21.87 nm). Overall, a modified granular starch surface with various characteristics can be provided by using hydrolysis enzymes and acid.
Starch surface modifications provide benefits in various applications as a carrier material. Tapioca starch slurry is prepared and treated with amylolytic enzymes and acid at various hydrolysis times. The amyloglucosidase‐treated samples show the highest specific surface area that corresponds to the largest pore volume. The data demonstrate that amyloglucosidase catalysis provides a strategy to generate potential carrier material from starch.
This study is conducted to elucidate the effect of differently engineered resistant maltodextrin (RMD) and resistant starch (RS) on human intestinal microbiotal fermentation. Different types of RMD ...and RS are used as the sole carbon sources for bacteria in feces from healthy volunteers. The cultured samples are analyzed for changes in microbial groups from which the prebiotic index (PI) is calculated. The metabolic activity of the microbiotal communities is monitored by efficiency of carbon utilization and short chain fatty acid (SCFA) profiling. Bifidobacteria and lactobacilli are found to be increased whereas clostridia (histolyticum subgroup) and bacteroides are decreased. RMD is more efficiently utilized than RS showing up to 78% of carbon source consumption. Utilization of RS provides the highest content of propionic and butyric acid while RMD shows a higher content of acetic and lactic acid. RMD and RS show a superior PI compared to that of glucose. Different types of molecular stearic hindrances, configurational hindrance for RMD, and conformational/aggregational hindrance for RS, prevent their hydrolytic utilization, directly influencing the human gut microbiotal composition and/or fermentation capability in different manners. RMD demonstrates the highest acetic acid content while RS3 and RS4 provide the highest butyric acid content.
The comparative effects of different types of resistant maltodextrin (RMD) and resistant starch (RS) on human colonic bacteria fermentation are investigated. Bacteria from human faeces are counted using standard plate count and fluorescent in situ hybridization (FISH). All RMD and RS can stimulate growth of bifidobacterial and lactobacilli result in an increase in PI value.
Escalating diabetes, obesity, cardiovascular disease, and bowel syndrome have increased consumer awareness of nutrition and energy values of starch products. Slowly digestible starch (SDS), slowly ...digestible maltooligosaccharides (SDM), and highly branched maltooligosaccharides, so called isomaltooligosaccharides (IMOs), generated by enzyme modification of starch, provide a new concept to meet consumer demands and solve urgent health‐associated problems. The combination of starch‐active enzymes in the glucanotransferase and glucanohydrolase families to produce slowly digestible‐ and non‐digestible α‐glucans has been widely studied, mainly focusing on the activities of branching enzyme (BE), amylomaltase (AM), and α‐transglucosidase (TGase). Products obtained from the action of these enzymes have resulted in completely novel types of maltooligosaccharides that are slowly degraded and therefore digested in the small intestine to maintain regulated blood glucose levels and suppressed glycemic‐index response. Some IMOs can even escape the small intestine and become fermented by micro‐organisms in the large intestine to produce health‐promoting short‐chain fatty acids such as butyric acid. Such slowly digested α‐glucans can regulate and trigger health‐promoting gut hormone release. Different novel production strategies of health‐promoting α‐glucans, their structures and nutritional effects are discussed here.
Enzyme technology, utilizing combinations of hydrolases and transferases, can be used to produce slowly digestible α‐glucans including slowly digestible starch (SDS), slowly digestible maltooligosaccharides (SDMs), and isomaltooligosaccharides (IMOs). Upon consumption, these can suppress the glycemic‐index response but also be fermented by gut microbiota generating health‐promoting short‐chain fatty acids.
White rice is considered a high glycemic index (GI) food and extruded reformed rice offers the opportunity to design a lower GI product. This study tested the effect of added soy protein isolate ...(SPI) or dietary fibers corn bran (CB), resistant maltodextrin (RMD) to delay
in vitro
digestion, and on human gastric emptying rate and satiety scoring. Starch digestion using a human simulated system showed a single-phase kinetic pattern for regular reformed rice and two-phase kinetic patterns for 20% supplemented extruded rice, which lowered the estimated glycemic index (eGI). For 20% SPI extruded rice (20SPI-ER), the first-phase rate constant (
k
1
) of cooked extruded rice was higher than its second-phase (
k
2
). Conversely, for 20% corn bran extruded rice (20CB-ER), a low value of
k
1
and high for
k
2
and
C
∞2
were found. The 20% RMD extruded rice (20RMD-ER) and the control exhibited a single-phase kinetic digestion with similar
k
values. The end-point of the second-phase digestion (
C
∞2
) and the eGI of cooked 20SPI-ER were lower than for fiber addition. These differences were speculated to be due to the heterogeneous matrices of the SPI and CB incorporated kernels, opposed to the homogeneous matrices of the RMD and control. Thus, extruded rice compositions were found that resulted in different starch digestion kinetics single phase and two-phase (
k
1
/
k
2
) high/low, low/high and were medium eGI with added protein or fiber. Compared to the control, only 20RMD-ER had lower gastric half-emptying time and 20CB-ER had higher subject satisfaction.
Extruded rice with added 20% soy protein isolate or corn bran showed two-phase (
k
1
/
k
2
) high/low, low/high kinetic patterns.
Mung bean starch is distinguished by its exceptional high amylose content and regulation of starch biosynthesis in leaves and storage tissues, such as seeds, share considerable similarities. Genetic ...engineering of starch composition and content, requires detailed knowledge of starch biosynthetic gene expression and enzymatic regulation. In this study we applied detailed transcriptomic analyses to unravel the global differential gene expression patterns in mung bean leaves and in seeds during various stages of development. The objective was to identify candidate genes and regulatory mechanisms that may enable generation of desirable seed qualities through the use of genetic engineering. Notable differences in gene expression, in particular low expression of the Protein Targeting to Starch (PTST), starch synthase (SS) 3, and starch branching enzyme1 (SBE1) encoding genes in developing seeds as compared to leaves were evident. These differences were related to starch molecular structures and granule morphologies. Specifically, the starch molecular size distribution at different stages of seed development correlated with the starch biosynthesis gene expression of the SBE1, SS1, granule-bound starch synthases (GBSS) and isoamylase 1 (ISA1) encoding genes. Furthermore, putative hormonal and redox controlled regulation were observed, which may be explained by abscisic acid (ABA) and indole-3-acetic acid (IAA) induced signal transduction, and redox regulation of ferredoxins and thioredoxins, respectively. The morphology of starch granules in leaves and developing seeds were clearly distinguishable and could be correlated to differential expression of SS1. Here, we present a first comprehensive transcriptomic dataset of developing mung bean seeds, and combined these findings may enable generation of genetic engineering strategies of for example starch biosynthetic genes for increasing starch levels in seeds and constitute a valuable toolkit for improving mung bean seed quality.
•Post-hydrothermal treatment improved the degree of crystal perfection.•Treatment sequences influenced on both thermal stability and enzyme digestibility.•The large lateral crystal size decreases the ...enzyme digestibility.•The higher amount of ordered structure decreases the enzyme digestibility.•Cooking stability depends on the initial RS content and crystal perfection.
Structural transformation of crystallized debranched cassava starch prepared by temperature cycling (TC) treatment and then subjected to annealing (ANN), heat-moisture treatment (HMT) and dual hydrothermal treatments of ANN and HMT was investigated. The relative crystallinity, lateral crystal size, melting temperature and resistant starch (RS) content increased for all hydrothermally treated samples, but the slowly digestible starch (SDS) content decreased. The RS content followed the order: HMT → ANN > HMT > ANN → HMT > ANN > TC, respectively. The HMT → ANN sample showed a larger lateral crystal size with more homogeneity, whereas the ANN → HMT sample had a smaller lateral crystal size with a higher melting temperature. After cooking at 50% moisture, the increased RS content of samples was observed, particularly for the ANN → HMT sample. These results suggest that structural changes of crystallized debranched starch during hydrothermal treatments depend on initial crystalline characteristics and treatment sequences, influencing thermal stability, enzyme digestibility, and cooking stability.
Native cassava flour can be modified to be instant flour by heating the cassava flour in ethanol solution. The impact of heating temperatures of 60, 80, and 100 °C (coded as ICF-60, ICF-80, and ...ICF-100) on the properties of instant cassava flour (ICF), including colour, morphological, and thermal properties, water absorption, and solubility indexes and pasting behaviour, were investigated. Results showed that ICF produced at higher temperatures exhibited lower lightness, higher redness, and yellowness values. ICF-60 and ICF-80 still displayed the granular forms and birefringence properties of native starches, while granules of ICF-100 were broken and partially lost their birefringence properties. Results of X-ray diffraction (XRD) technique and differential scanning calorimetry (DSC) analysis suggested that the amylopectin double helixes of crystalline regions within the structure of ICF orientated to more perfect conformation before they were disrupted at the highest heating temperature (100 °C). During hydration, the starch granules of ICF-60 and ICF-80 absorbed water into their granules; meanwhile, ICF-100 entrapped water within the matrix formed by the entanglements of ICF-100 particles. Results of pasting behaviour analysis indicated that ICF-60 and ICF-80 showed better thermal stability while ICF-100 exhibited the highest cold viscosity.
The production of functional food ingredients has been promoted in recent years in response to the consumer attention on personal health and well-being demand. Isomalto-oligosaccharides (IMOs) are ...derived from starch and are a mixture of oligosaccharides with degree of polymerization (DP) ranging 2–10. IMOs exhibit low glycemic index and are classified as prebiotics. Increasing consumer demand for low glycemic foods has recently advanced both academic research industrial developments in the IMOs area. An increasing number of scientific studies highlight enzymatic modification of starch, digestibility and prebiotics fermentability. Additionally, recent studies point at IMOs versatile functionality as food ingredient, pharmaceutical- and cosmetic precursor, all of which are effects of their small molecular size resulting in high solubility and low viscosity. As a result, the numbers of IMOs-related patent classifications for food, foodstuff, ingredient, medical and veterinary purposes, as listed by the Cooperative Patent Classification (CPC) and International Patent Classification (IPC), have steadily increased over the past 26 years. Interestingly, IMOs have been commercially available for decades in Japan but only recently, IMOs products were launched for the US, European and Canadian markets. The IMOs selling rate is now strongly growing with significant revenues taking off in 2017. In this review, we will give a brief overview and identify some main challenges for IMOs product development from both academic and commercial points of view focusing on their wide variation in chemical and physical properties, functionality in foods, production technology, digestibility, prebiotics fermentability and health-associated functions. Finally, we will project from the current IMOs market situation and discuss potentials for an emerging multi-niche IMOs market as directed by consumer trends and intellectual property right (IPR) situations. This short review is widely intended for scientists, traders and the general public who have interest in prospects of IMOs.
•IMOs exhibit low glycemic index and are classified as prebiotics.•Increasing consumer demand has recently advanced academic research and industrial developments in the IMO area.•The numbers of IMO-related patent have steadily increased over the past 26 years.•The IMO selling rate is now strongly growing with significant revenues taking off in 2017.
•Porous rice starch was obtained following treatment with amyloglucosidase (AMG) or maltogenic α-amylase (MA).•The range of pore diameters of MA treatment was narrower than that of AMG.•MA treatment ...increased short amylopectin chains of rice starch and changed thermal and pasting properties.•MA provides a novel alternative enzyme for producing porous starch.
Porous starch is attractive by providing high surface area for many applications. In this study amyloglucosidase (AMG) and maltogenic α-amylase (MA) were investigated in direct comparison to elucidate potential effects in producing porous starch using high amylose rice starch as a substrate. Both enzymes generated pores at the surface as illustrated by Scanning Electron Microscopy (SEM). The enzyme-treated granules had higher relative crystallinity as deduced from Wide Angle X-ray Scattering (WAXS). MA treatment increased the number of short amylopectin chains and decreased the molecular weight with extended incubation time. The MA-treated starch had higher solubility whereas swelling capacity, amylose content, peak viscosity, final viscosity, breakdown and setback of both treatments were decreased compared to the control. Enzymatic treatments produced starch with delayed gelatinization temperature and increased the enthalpy. The results demonstrate that porous rice starch can provide different functionalities depending on the enzyme mechanisms, extending the range of applications.
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