Amylolytic enzymes and products derived from starch: a review

Enzyme-Mediated Exponential Glucose Release: A Model-Based Strategy for Continuous Defined Fed-Batch in Small-Scale Cultivations

Miniaturized cultivation systems offer the potential to enhance experimental throughput in bioprocess development. However, they usually lack the miniaturized pumps necessary for fed-batch mode, which is commonly employed in industrial bioprocesses. An alternative are enzyme-mediated glucose release systems from starch-derived polymers, facilitating continuous glucose supply. Nevertheless, while the glucose release, and thus the feed rate, is controlled by the enzyme concentration, it also strongly depends on the type of starch derivative, and the culture conditions as well as pH and temperature. So far it was not possible to implement controlled feeding strategies (e.g., exponential feeding). In this context, we propose a model-based approach to achieve precise control over enzyme-mediated glucose release in cultivations. To this aim, an existing mathematical model was integrated into a computational framework to calculate setpoints for enzyme additions. We demonstrate the ability of the tool to maintain different pre-defined exponential growth rates during Escherichia coli cultivations in parallel mini-bioreactors integrated into a robotic facility. Although in this case study, the intermittent additions of enzyme and dextrin were performed by a liquid handler, the approach is adaptable to manual applications. Thus, we present a straightforward and robust approach for implementing defined continuous fed-batch processes in small-scale systems, where continuous feeding was only possible with low accuracy or high technical efforts until now.

Nutritional epigenetics education improves diet and attitude of parents of children with autism or attention deficit/hyperactivity disorder

BACKGROUND

Unhealthy maternal diet leads to heavy metal exposures from the consumption of ultra-processed foods that may impact gene behavior across generations, creating conditions for the neurodevelopmental disorders known as autism and attention deficit/hyperactivity disorder (ADHD). Children with these disorders have difficulty metabolizing and excreting heavy metals from their bloodstream, and the severity of their symptoms correlates with the heavy metal levels measured in their blood. Psychiatrists may play a key role in helping parents reduce their ultra-processed food and dietary heavy metal intake by providing access to effective nutritional epigenetics education.

AIM

To test the efficacy of nutritional epigenetics instruction in reducing parental ultra-processed food intake.

METHODS

The study utilized a semi-randomized test and control group pretest-posttest pilot study design with participants recruited from parents having a learning-disabled child with autism or ADHD. Twenty-two parents who met the inclusion criteria were randomly selected to serve in the test (n = 11) or control (n = 11) group. The test group participated in the six-week online nutritional epigenetics tutorial, while the control group did not. The efficacy of the nutritional epigenetics instruction was determined by measuring changes in parent diet and attitude using data derived from an online diet survey administered to the participants during the pre and post intervention periods. Diet intake scores were derived for both ultra-processed and whole/organic foods. Paired sample t-tests were conducted to determine any differences in mean diet scores within each group.

RESULTS

There was a significant difference in the diet scores of the test group between the pre- and post-intervention periods. The parents in the test group significantly reduced their intake of ultra-processed foods with a pre-intervention diet score of 70 (mean = 5.385, SD = 2.534) and a post-intervention diet score of 113 (mean = 8.692, SD = 1.750) and the paired t-test analysis showing a significance of P < 0.001. The test group also significantly increased their consumption of whole and/or organic foods with a pre-intervention diet score of 100 (mean = 5.882, SD = 2.472) and post-intervention diet score of 121 (mean = 7.118, SD = 2.390) and the paired t-test analysis showing a significance of P < 0.05.

CONCLUSION

Here we show nutritional epigenetics education can be used to reduce ultra-processed food intake and improve attitude among parents having learning-disabled children with autism or ADHD.

Recent advances in the synthesis and medicinal perspective of pyrazole-based α-amylase inhibitors as antidiabetic agents

Diabetes is a serious health threat across the globe, claiming millions of lives worldwide. Among the various strategies employed, inhibition of α-amylase is a therapeutic protocol for the management of Type 2 diabetes mellitus. α-Amylase is a crucial enzyme involved in the breakdown of dietary starch into simpler units. However, the clinically used α-amylase inhibitors have various drawbacks. Therefore, design and development of novel α-amylase inhibitors have gained significant attention. The pyrazole motif has been identified as a versatile scaffold in medicinal chemistry, and recent studies have led to the identification of various pyrazole-based α-amylase inhibitors. This review compiles therapeutic implications of pyrazole-appended α-amylase inhibitors; their synthesis, biological activities, structure-activity relationships and molecular docking studies are discussed.

Application of Starch, Cellulose, and Their Derivatives in the Development of Microparticle Drug-Delivery Systems

Micro- and nanotechnologies have been intensively studied in recent years as novel platforms for targeting and controlling the delivery of various pharmaceutical substances. Microparticulate drug delivery systems for oral, parenteral, or topical administration are multiple unit formulations, considered as powerful therapeutic tools for the treatment of various diseases, providing sustained drug release, enhanced drug stability, and precise dosing and directing the active substance to specific sites in the organism. The properties of these pharmaceutical formulations are highly dependent on the characteristics of the polymers used as drug carriers for their preparation. Starch and cellulose are among the most preferred biomaterials for biomedical applications due to their biocompatibility, biodegradability, and lack of toxicity. These polysaccharides and their derivatives, like dextrins (maltodextrin, cyclodextrins), ethylcellulose, methylcellulose, hydroxypropyl methylcellulose, carboxy methylcellulose, etc., have been widely used in pharmaceutical technology as excipients for the preparation of solid, semi-solid, and liquid dosage forms. Due to their accessibility and relatively easy particle-forming properties, starch and cellulose are promising materials for designing drug-loaded microparticles for various therapeutic applications. This study aims to summarize some of the basic characteristics of starch and cellulose derivatives related to their potential utilization as microparticulate drug carriers in the pharmaceutical field.

Synthesis, spectroscopic findings, SEM/EDX, DFT, and single-crystal structure of Hg/Pb/Cu-SCN complexes: In silico ADME/T profiling and promising antibacterial activities

This work contemplates synthesizing M-SCN crystal compounds (M = Hg/Pb/Cu) in the presence of respective metal salts and exogenous ancillary SCN^- ion by slowly evaporating the mixed solvent (CH₃OH + ACN). The complexes were characterized by spectroscopy, SEM/EDX, and X-ray crystallography. The Hg-Complex, Pb-Complex, and Cu-Complex crystallize in the monoclinic space group (Z = 2/4). The crystal packing fascinatingly consists of weak covalent bonding and Pb⋯S contacts of tetrel type bond. Here are the incredible supramolecular topographies delineated by the Hirshfeld surface and 2D fingerprint plot. The B3LYP/6-311++G (d, p) level calculations in the gas phase optimized the compound's geometry. The energy difference (Δ) between HOMO-LUMO and global reactivity parameters investigates the complex's energetic activity. MESP highlights the electrophilic/nucleophilic sites and H-bonding interactions. Molecular docking was conceded with the Gram- + ve bacterium Bacillus Subtilis (PDB ID: 6UF6) and the Gram-ve bacterium Proteus Vulgaris (PDB ID: 5HXW) to authenticate the bactericidal activity. ADME/T explains the various pharmacological properties. In addition, we studied the antibacterial activity with MIC (μg/mL) values and time-kill kinetics against Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (ATCC 6635) as Gram-positive, Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922) as Gram-negative bacteria.

A practical approach to producing the single-arm linear dextrin, a chimeric glucosaccharide containing an (α-1 → 4) linked portion at the nonreducing end of an (α-1 → 6) glucochain

How to improve the solubility of linear dextrins (LD) and retain their characteristic helix amphiphilic cavities with flexible embedding capability, is a question worth exploring without adding new chemical groups. The strategy presented in this study is to attach a highly flexible (α-1 → 6) glucochain at the reducing end of LD by preparing a new type of dextrin, referred to as single-arm linear dextrin (SLD). In the actual synthesis, an (α-1 → 6) linked oligosaccharide of DP¯ 10.7 (PDI = 1.28) was formed by extension of glucose units onto sucrose (2 M) by using L940W mutant of the glucansucrase GTF180-ΔN firstly. Next using γ-CD as glucosylation donor γ-CGTase extended this (α-1 → 6) glucochain with (α-1 → 4) bonds. SLD is a chimeric glucosaccharide comprising an (α-1 → 4) linked part (DP¯ 10.5) attached to the nonreducing end of an (α-1 → 6) glucochain as verified by enzyme fingerprinting and ¹H NMR. Furthermore, SLD was validated to show greatly improved solubility and dispersibility of resveratrol in water, as indicated by a 3.12-fold enhancement over the solubility in the presence of 0.014 M SLD. This study provided a new strategy for solving the solubility problem of LD and opens possibilities for new design of the fine structure of starch-like materials.

Higher rates of autism and attention deficit/hyperactivity disorder in American children: Are food quality issues impacting epigenetic inheritance?

In the United States, schools offer special education services to children who are diagnosed with a learning or neurodevelopmental disorder and have difficulty meeting their learning goals. Pediatricians may play a key role in helping children access special education services. The number of children ages 6-21 in the United States receiving special education services increased 10.4% from 2006 to 2021. Children receiving special education services under the autism category increased 242% during the same period. The demand for special education services for children under the developmental delay and other health impaired categories increased by 184% and 83% respectively. Although student enrollment in American schools has remained stable since 2006, the percentage distribution of children receiving special education services nearly tripled for the autism category and quadrupled for the developmental delay category by 2021. Allowable heavy metal residues remain persistent in the American food supply due to food ingredient manufacturing processes. Numerous clinical trial data indicate heavy metal exposures and poor diet are the primary epigenetic factors responsible for the autism and attention deficit hyperactivity disorder epidemics. Dietary heavy metal exposures, especially inorganic mercury and lead may impact gene behavior across generations. In 2021, the United States Congress found heavy metal residues problematic in the American food supply but took no legislative action. Mandatory health warning labels on select foods may be the only way to reduce dietary heavy metal exposures and improve child learning across generations.

Difference of microbial community and gene composition with saccharification function between Chinese nongxiangxing daqu and jiangxiangxing daqu

BACKGROUND

The saccharification function of daqu is usually characterized by two indicators: saccharification power and liquefaction power. Daqu provides diverse microbial saccharifying enzymes for hydrolyzing carbohydrate in Baijiu fermenting grain. Obviously, the composition of microbial communities and enzymatic genes in different types of daqu cultured at varied temperatures is different. However, these differences in saccharification function are not fully understood.

RESULTS

The findings suggested that the saccharification power and liquefaction power of jiangxiangxing daqu were lower than those of nongxiangxing daqu throughout the production process. We employed metagenomics to find evidence that a mode of multiple saccharifying enzymes involving amylase, cellulase and hemicellulase originating from various microbes exists in daqu. Moreover, a totality of 541 related differential genes were obtained, some of which, annotated to genera of Aspergillus, Lactobacillus and Weissella, were significantly enriched (P < 0.05) in nongxiangxing daqu, while others, annotated to thermophilic genera of Virgibacillus, Bacillus, Kroppenstedtia and Saccharopolyspora, showed a higher relative abundance in jiangxiangxing daqu (P < 0.05).

CONCLUSION

Various microbial communities of daqu showed diverse saccharification capacity during cultivation of different parameters. These findings are helpful in comprehending the saccharification functional genes of daqu. © 2022 Society of Chemical Industry.

Optimization of a Simultaneous Enzymatic Hydrolysis to Obtain a High-Glucose Slurry from Bread Waste

Bread and bakery products are among the most discarded food products in the world. This work aims to investigate the potential use of wasted bread to obtain a high-glucose slurry. Simultaneous hydrolysis of wasted bread using α-amylase and glucoamylase was carried out performing liquefaction and saccharification at the same time. This process was compared with a traditional sequential hydrolysis. Temperature and pH conditions were optimized using a response surface design determining viscosity, reducing sugars and glucose concentration during the enzymatic processes. The optimal conditions of pH and temperature in the saccharification stage and the simultaneous hydrolysis were pretty similar. Results show that the slurry produced with simultaneous process had a similar glucose yield at 2 h, and at 4 h a yield higher than that obtained by the sequential method of 4 h and could reduce time and energy.

Chemical remediation and advanced oxidation process of polychlorinated biphenyls in contaminated soils: a review

Polychlorinated biphenyls (PCBs) are synthetic organic compounds ubiquitously distributed worldwide due to their persistence, long-range atmospheric transport, and bioaccumulation. Owing to teratogenic properties, PCBs are a global environmental problem. Different physical, biological, and chemical techniques are utilized for the remediation of PCBs. This review paper discusses the recent development in photocatalytic and chemical techniques for the remediation of PCBs in contaminated soils. In particular, the photocatalytic degradation of PCBs combined with soil washing, Fe-based reductive dichlorination, and advanced oxidation process (Fenton advance oxidation and persulfate oxidation) is discussed and reviewed in detail. The review suggested that advanced oxidation is an efficient remediation technique with 77-99% of removal efficiency of PCBs. Persulfate oxidation is the most suitable technique which could work at normal environmental conditions (such as pH, temperature, soil organic matter (SOM), etc.). Different environmental factors such as pH, temperature, and SOM affect the Fe-based reductive dechlorination and Fenton advance oxidation techniques. The surfactants and organic solvents used in soil washing combined with photocatalytic degradation affect the degradation capability of these techniques. This review will contribute to PCBs degradation by the detailed discussion of development in chemical technique future perspective and research needs.

Molecular brewing: The molecular structural effects of starch adjuncts on barley malt brewing performances

In this study, the effects of starch adjuncts with different fine molecular structures obtained by size-exclusion chromatography on the mashing and fermentation efficiencies of barley malts were investigated. Following fermentation, violate compounds of freshly-fermented beer samples were determined by headspace-solid-phase microextraction coupled with gas chromatography-mass spectrometry analysis (HS-SMPE-GC-MS). High performance liquid chromatography results showed that depending on their molecular structures, starch adjuncts addition significantly increased wort maltose and maltotriose content, whereas reducing the glucose content and thus both the ratios of glucose and maltotriose to that of the maltose. The whole fermentation by dry beer yeast was finished within the first 48 h and reached to equilibrium for the rest 72 h, represented by the stable soluble protein content. Results also showed that the addition of starch adjuncts resulted into increased alcohol content, which was mainly attributed to the altered glucose/maltose ratio. The HS-SPME-GC-MS results showed that whether or not with starch adjuncts addition, the composition of violate compounds were not significantly influenced, their content, on the contrary, were altered, represented by different peak heights. This study provides important information concerning the molecular effects of starch adjuncts on brewing performances of barley malts, and also provides a new pathway for choosing suitable types of adjuncts for making beer with better quality.

Rational reformation of Corynebacterium glutamicum for producing L-lysine by one-step fermentation from raw corn starch

This article focuses on engineering Corynebacterium glutamicum to produce L-lysine efficiently from starch using combined method of "classical breeding" and "genome breeding." Firstly, a thermo-tolerable L-lysine-producing C. glutamicum strain KT_45-6 was obtained after multi-round of acclimatization at high temperature. Then, amylolytic enzymes were introduced into strain KT_45-6, and the resultant strains could use starch for cell growth and L-lysine production except the strain with expression of isoamylase. In addition, co-expression of amylolytic enzymes showed a good performance in starch degradation, cell growth and L-lysine production, especially co-expression of α-amylase (AA) and glucoamylase (GA). Moreover, L-lysine yield was increased by introducing AA-GA fusion protein (i.e., strain KT_45-6S-5), and finally reached to 23.9 ± 2.3 g/L in CgXII^IPM-medium. It is the first report of an engineered L-lysine-producing strain with maximum starch utilization that may be used as workhorse for producing amino acid using starch as the main feedstock. KEY POINTS: • Thermo-tolerable C. glutamicum was obtained by temperature-induced adaptive evolution. • The fusion order between AA and GA affects the utilization efficiency of starch. • C. glutamicum with starch utilization was constructed by optimizing amylases expression.

Connecting inorganic mercury and lead measurements in blood to dietary sources of exposure that may impact child development

Pre-natal and post-natal chemical exposures and co-exposures from a variety of sources including contaminated air, water, soil, and food are common and associated with poorer birth and child health outcomes. Poor diet is a contributing factor in the development of child behavioral disorders. Child behavior and learning can be adversely impacted when gene expression is altered by dietary transcription factors such as zinc insufficiency or deficiency or by exposure to toxic substances permitted in our food supply such as mercury, lead, or organophosphate pesticide residue. Children with autism spectrum disorder and attention deficit hyperactivity disorders exhibit decreased or impaired PON1 gene activity which is needed by the body to metabolize and excrete neurotoxic organophosphate pesticides. In this current review we present an updated macroepigenetic model that explains how dietary inorganic mercury and lead exposures from unhealthy diet may lead to elevated blood mercury and/or lead levels and the development of symptoms associated with the autism and attention deficit-hyperactivity disorders. PON1 gene activity may be suppressed by inadequate dietary calcium, selenium, and fatty acid intake or exposures to lead or mercury. The model may assist clinicians in diagnosing and treating the symptoms associated with these childhood neurodevelopmental disorders. Recommendations for future research are provided based on the updated model and review of recently published literature.

Amylases: Biofilm Inducer or Biofilm Inhibitor?

Biofilm is a syntrophic association of sessile groups of microbial cells that adhere to biotic and abiotic surfaces with the help of pili and extracellular polymeric substances (EPS). EPSs also prevent penetration of antimicrobials/antibiotics into the sessile groups of cells. Hence, methods and agents to avoid or remove biofilms are urgently needed. Enzymes play important roles in the removal of biofilm in natural environments and may be promising agents for this purpose. As the major component of the EPS is polysaccharide, amylase has inhibited EPS by preventing the adherence of the microbial cells, thus making amylase a suitable antimicrobial agent. On the other hand, salivary amylase binds to amylase-binding protein of plaque-forming Streptococci and initiates the formation of biofilm. This review investigates the contradictory actions and microbe-associated genes of amylases, with emphasis on their structural and functional characteristics.

Comparison of physicochemical and mechanical properties of edible films made from navy bean and corn starches

BACKGROUND

Recently, there has been a great interest in developing new applications of edible dry beans (Phaseolus vulgaris L.). The utilization of starch, comprising the major component of dry bean seeds, for the preparation of edible films has just emerged.

RESULTS

In the present study, we chose navy bean as a model dry bean source, isolated its starch component, prepared edible films with different formulations (35 and 40 g L^-1 ), and compared these with the films made using isolated and commercial corn starches. Sunflower oil at 10 g L^-1 was dispersed into film-forming solution to design composite films. The water vapor barrier property, mechanical properties and microstructure of starch films from navy bean and corn were studied to evaluate their potential for use in food packaging. All of the films had smooth and uniform surface and were transparent.

CONCLUSION

Navy bean starch film showed physicochemical and mechanical properties comparable to corn starch films, and the addition of sunflower oil could further improve the water vapor barrier and mechanical properties of films. The findings obtained in the present study demonstrate the potential of using navy bean starch to prepare edible films. © 2020 Society of Chemical Industry.

Characterizing moisture uptake and plasticization effects of water on amorphous amylose starch models using molecular dynamics methods

Dynamics and thermophysical properties of amorphous starch were explored using molecular dynamics (MD) simulations. Using the OPLS3e force field, simulations of short amylose chains in water were performed to determine force field accuracy. Using well-tempered metadynamics, a free energy map of the two glycosidic angles of an amylose molecule was constructed and compared with other modern force fields. Good agreement of torsional sampling for both solvated and amorphous amylose starch models was observed. Using combined grand canonical Monte Carlo (GCMC)/MD simulations, a moisture sorption isotherm curve is predicted along with temperature dependence. Concentration-dependent activation energies for water transport agree quantitatively with previous experiments. Finally, the plasticization effect of moisture content on amorphous starch was investigated. Predicted glass transition temperature (T_g) depression as a function of moisture content is in line with experimental trends. Further, our calculations provide a value for the dry T_g for amorphous starch, a value which no experimental value is available.

In Vitro Prebiotic Effects of Malto-Oligosaccharides Containing Water-Soluble Dietary Fiber

This study measured the proliferative activity of malto-oligosaccharide (MOS) as a prebiotic against Bifidobacteria, resistance to digestion in vitro, and changes during in vitro fermentation by human fecal microorganisms. It consisted of 21.74%, 18.84%, and 11.76% of maltotriose, maltotetraose, and maltopentaose produced by amylase (HATT), respectively. When 1% of MOS was added to a modified PYF medium as the carbon source, proliferation of Bifidobacterium breve was increased significantly. During the in vitro digestion test, MOS was partially degraded by intestinal enzymes. Fermentation characteristics by human fecal microorganisms were evaluated by adding 1% galacto-oligosaccharide (GOS), as well as 1% and 2% MOS as carbon sources to the basal medium, respectively. In comparison with the addition of 1% of MOS and GOS, the total short chain fatty acid (SCFA) content increased over time when 2% of MOS was added. The species diversity and richness of intestinal microbiota increased significantly with 2% MOS compared to those with 1% GOS. In addition, the 2% addition of MOS reduced intestinal pathobiont microorganisms and increased commensal microorganisms including Bifidobacterium genus. Collectively, MOS produced by amylase increased the SCFA production and enhanced the growth of beneficial bacteria during in vitro fermentation by human fecal microbiota.

Enzyme Kinetics by Isothermal Titration Calorimetry: Allostery, Inhibition, and Dynamics

Isothermal titration calorimetry (ITC) involves accurately measuring the heat that is released or absorbed in real time when one solution is titrated into another. This technique is usually used to measure the thermodynamics of binding reactions. However, there is mounting interest in using it to measure reaction kinetics, particularly enzymatic catalysis. This application of ITC has been steadily growing for the past two decades, and the method is proving to be sensitive, generally applicable, and capable of providing information on enzyme activity that is difficult to obtain using traditional biochemical assays. This review aims to give a broad overview of the use of ITC to measure enzyme kinetics. It describes several different classes of ITC experiment, their strengths and weaknesses, and recent methodological advancements. A summary of applications in the literature is given and several examples where ITC has been used to investigate challenging aspects of enzyme behavior are presented in more detail. These include examples of allostery, where small-molecule binding outside the active site modulates activity. We describe the use of ITC to measure the strength, mode (i.e., competitive, uncompetitive, or mixed), and association and dissociation kinetics of enzyme inhibitors. Further, we provide examples of ITC applied to complex, heterogeneous mixtures, such as insoluble substrates and live cells. These studies exemplify the wide range of problems where ITC can provide answers, and illustrate the versatility of the technique and potential for future development and applications.

Amylase-Producing Maltooligosaccharide Provides Potential Relief in Rats with Loperamide-Induced Constipation

Constipation is a chronic disease caused by infrequent, inadequate, and difficult bowel movements. The present study aimed to evaluate the potential laxative effect of maltooligosaccharide (MOS) on loperamide-induced constipation in a rat model. In vitro experiments were conducted to evaluate the effect of MOS on the growth of lactic acid bacteria. Moreover, to examine the effect of MOS administration on Sprague-Dawley (SD) rats with loperamide-induced constipation, the drinking water for the rats was supplemented with 10% or 15% of MOS for 14 days, and, thereafter, the improvement in constipation was assessed. For this, the rats were divided into five groups: normal (Nor), loperamide-induced constipated (Con), positive control (15% of dual-oligosaccharide (DuO-15)), 10% MOS treated (MOS-10), and 15% MOS-treated (MOS-15). In an in vitro test, MOS treatment promoted the growth of lactic acid bacteria except Lactobacillus bulgaricus. Treatment with higher MOS dose relieved constipation in rats by improving the fecal pellet and water content. Furthermore, in the high MOS dose group, the cecal short-chain fatty acid levels significantly increased compared to those in the control group (P < 0.001). MOS treatment also improved the mucosal thickness as well as mucin secretion and increased the area of intestinal Cajal cells compared to that in the control group (P < 0.001). These findings suggest that MOS relieves constipation and has beneficial effect on the gastrointestinal tract, and, therefore, it can be used as an ingredient in functional foods for treating constipation or improving intestinal health.

The Importance of Lactose in the Human Diet: Outcomes of a Mexican Consensus Meeting

Lactose is a unique component of breast milk, many infant formulas and dairy products, and is widely used in pharmaceutical products. In spite of that, its role in human nutrition or lactose intolerance is generally not well-understood. For that reason, a 2-day-long lactose consensus meeting with health care professionals was organized in Mexico to come to a set of statements for which consensus could be gathered. Topics ranging from lactase expression to potential health benefits of lactose were introduced by experts, and that was followed by a discussion on concept statements. Interestingly, lactose does not seem to induce a neurological reward response when consumed. Although lactose digestion is optimal, it supplies galactose for liver glycogen synthesis. In infants, it cannot be ignored that lactose-derived galactose is needed for the synthesis of glycosylated macromolecules. At least beyond infancy, the low glycemic index of lactose might be metabolically beneficial. When lactase expression decreases, lactose maldigestion may lead to lactose intolerance symptoms. In infancy, the temporary replacing of lactose by other carbohydrates is only justified in case of severe intolerance symptoms. In those who show an (epi)genetic decrease or absence of lactase expression, a certain amount (for adults mostly up to 12 g per portion) of lactose can still be consumed. In these cases, lactose shows beneficial intestinal-microbiota-shaping effects. Avoiding lactose-containing products may imply a lower intake of other important nutrients, such as calcium and vitamin B12 from dairy products, as well as an increased intake of less beneficial carbohydrates.

Inhibitory Effects on NO Production and DPPH Radicals and NBT Superoxide Activities of Diarylheptanoid Isolated from Enzymatically Hydrolyzed Ehthanolic Extract of Alnus sibirica

Alnus sibirica (AS) is geographically distributed in Korea, Japan, Northeast China, and Russia. Various anti-oxidant, anti-inflammation, anti-atopic dermatitis and anti-cancer biological effects of AS have been reported. Enzymatic hydrolysis decomposes the sugar bond attached to glycoside into aglycone which, generally, has a superior biological activity, compared to glycoside. Enzymatic hydrolysis of the extract (EAS) from AS was processed and the isolated compounds were investigated—hirsutanonol (1), hirsutenone (2), rubranol (3), and muricarpon B (4). The structures of these compounds were elucidated, and the biological activities were assessed. The ability of EAS and the compounds (1–4) to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and Nitroblue tetrazolium (NBT) superoxide, and to inhibit NO production was evaluated in vitro. EAS showed more potent antioxidant and anti-inflammatory activity than AS. All investigated compounds showed excellent antioxidant and anti-inflammatory activities.

Synthesis of biopolymeric particles loaded with phosphorus and potassium: characterisation and release tests

The authors synthesised nanoparticles (NPs) loaded with P and K from KH2 PO4 using gelatin type‐A and type‐B, and sodium alginate as carriers. Using type‐A and type‐B gelatin, quasi‐spherical particles were obtained, with average sizes of 682 and 856 nm, respectively; with sodium alginate, the resulting NPs exhibited spherical shapes and 600 nm particle average size. The authors found an interaction between KH2 PO4 and alginate via the hydrogen bonds existent among the carboxylic groups of the carbohydrate and the OH‐groups of the H2 PO4 ‐; interactions among gelatin types with the OH‐groups and the H2 PO4 ‐ion were also observed. Adding trypsin to the distilled water solutions of the NPs coated with type‐A gelatin increased the concentration of P in the solution by threefold, while increasing that of K increased by 2.6‐fold. Conversely, adding α ‐amylase to the water solutions with sodium alginate increased the P and K concentrations in the solution by nearly 1.3‐ and 1.1‐fold, respectively. Thus, sodium alginate resulted in NPs with smaller sizes and better spherical formations, though with a high polydispersity index and lower release rate of P and K . This low release rate represents an advantage since plants demand nutrients for long periods, and conventional fertilisers display low use efficiency.

Preparation of Magnetic Cross-Linked Amyloglucosidase Aggregates: Solving Some Activity Problems

The preparation of Cross-Linked Enzyme Aggregates (CLEAs) is a simple and cost-effective technique capable of generating insoluble biocatalysts with high volumetric activity and improved stability. The standard CLEA preparation consists of the aggregation of the enzyme and its further crosslinking, usually with glutaraldehyde. However, some enzymes have too low a content of surface lysine groups to permit effective crosslinking with glutaraldehyde, requiring co-aggregation with feeders rich in amino groups to aid the formation of CLEAs. The co-aggregation with magnetic particles makes their handling easier. In this work, CLEAs of a commercial amyloglucosidase (AMG) produced by Aspergillus niger were prepared by co-aggregation in the presence of polyethyleneimine (PEI) or starch with aminated magnetic nanoparticles (MNPs) or bovine serum albumin (BSA). First, CLEAs were prepared only with MNPs at different glutaraldehyde concentrations, yielding a recovered activity of around 20%. The addition of starch during the precipitation and crosslinking steps nearly doubled the recovered activity. Similar recovered activity (around 40%) was achieved when changing starch by PEI. Moreover, under the same conditions, AMG co-aggregated with BSA was also synthesized, yielding CLEAs with very similar recovered activity. Both CLEAs (co-aggregated with MNPs or BSA) were four times more stable than the soluble enzyme. These CLEAs were evaluated in the hydrolysis of starch at typical industrial conditions, achieving more than 95% starch-to-glucose conversion, measured as Dextrose Equivalent (DE). Moreover, both CLEAS could be reused for five cycles, maintaining a DE of around 90%. Although both CLEAs had good properties, magnetic CLEAs could be more attractive for industrial purposes because of their easy separation by an external magnetic field, avoiding the formation of clusters during the filtration or centrifugation recovery methods usually used.

Production, purification and characterization of raw starch hydrolyzing thermostable acidic α-amylase from hot springs, India

Alpha-amylase is an important hydrolytic enzyme used for various industrial processes. In the present study, Geobacillus bacterium (K1C), producing a thermostable α-amylase was isolated from Manikaran hot springs, India. We have purified and characterized the biochemical properties of α-amylase. The optimum temperature and pH for α-amylase activity was 80 °C and pH 6.0 respectively. The far-UV CD spectra of the enzyme indicated the presence of random coil conformation and showed an intermediate phase during temperature-induced unfolding. In the presence of substrate, thermostability of the α-amylase was increased as 50% initial activity was retained at 70 °C for 6 h and at 80 °C for 2 h. Moreover, the enzyme also showed remarkable pH stability as 90% of the initial activity was retained even after 48 h of incubation at pH 5.0, 6.0 and 7.0. Interestingly, amylase activity of the purified enzyme was Ca²⁺independent, whereas the complete inhibition of activity was observed in the presence of Cu²⁺, Pb²⁺, and Hg²⁺. The purified α-amylase was stable in the presence of detergents, organic solvents and Proteinase K. Furthermore, it exhibited the ability to hydrolyze raw starches (e.g. rice, wheat, corn, potato) efficiently; thus this enzyme has the potential to be used for industrial applications.

The scientific basis for healthful carbohydrate profile

Dietary guidelines indicate that complex carbohydrates should provide around half of the calories in a balanced diet, while sugars (i.e., simple carbohydrates) should be limited to no more than 5-10% of total energy intake. To achieve this public health goal a collective effort from different entities including governments, food & beverage industries and consumers is required. Some food companies have committed to continually reduce sugars in their products. Different solutions can be used to replace sugars in food products but it is important to ensure that these solutions are more healthful than the sugars they replace. The objectives of this paper are, (1) to identify carbohydrates and carbohydrates sources to promote and those to limit for dietary intake and food product development, based on current knowledge about the impact of carbohydrates on the development of dental caries, obesity and cardio-metabolic disorders (2) to evaluate the impact of food processing on the quality of carbohydrates and (3) to highlight the challenges of developing healthier products due to the limitations and gaps in food regulations, science & technology and consumer education.

Biotechnological Processes in Microbial Amylase Production

Amylase is an important and indispensable enzyme that plays a pivotal role in the field of biotechnology. It is produced mainly from microbial sources and is used in many industries. Industrial sectors with top-down and bottom-up approaches are currently focusing on improving microbial amylase production levels by implementing bioengineering technologies. The further support of energy consumption studies, such as those on thermodynamics, pinch technology, and environment-friendly technologies, has hastened the large-scale production of the enzyme. Herein, the importance of microbial (bacteria and fungi) amylase is discussed along with its production methods from the laboratory to industrial scales.

The Gastrointestinal Tract as a Key Target Organ for the Health-Promoting Effects of Dietary Proanthocyanidins

Proanthocyanidins (PACs) are polymers of flavan-3-ols abundant in many vegetable foods and beverages widely consumed in the human diet. There is increasing evidence supporting the beneficial impact of dietary PACs in the prevention and nutritional management of non-communicable chronic diseases. It is considered that PACs with a degree of polymerization >3 remain unabsorbed in the gastrointestinal (GI) tract and accumulate in the colonic lumen. Accordingly, the GI tract may be considered as a key organ for the healthy-promoting effects of dietary PACs. PACs form non-specific complexes with salivary proteins in mouth, originating the sensation of astringency, and with dietary proteins, pancreatic enzymes, and nutrient transporters in the intestinal lumen, decreasing the digestion and absorption of carbohydrates, proteins, and lipids. They also exert antimicrobial activities, interfering with cariogenic or ulcerogenic pathogens in the mouth (Streptococcus mutans) and stomach (Helicobacter pylori), respectively. Through their antioxidant and antiinflammatory properties, PACs decrease inflammatory processes in animal model of gastric and colonic inflammation. Interestingly, they exert prebiotic activities, stimulating the growth of Lactobacillus spp. and Bifidobacterium spp. as well as some butyrate-producing bacteria in the colon. Finally, PACs are also metabolized by the gut microbiota, producing metabolites, mainly aromatic acids and valerolactones, which accumulate in the colon and/or are absorbed into the bloodstream. Accordingly, these compounds could display biological activities on the colonic epithelium or in extra-intestinal tissues and, therefore, contribute to part of the beneficial effects of dietary PACs.

Anatomy and Physiology of the Small Bowel

Comprehension of small intestine physiology and function provides a framework for the understanding of several important disease pathways of the gastrointestinal system. This article reviews the development, anatomy and histology of the small bowel in addition to physiology and digestion of key nutrients.

Marine Microbiological Enzymes: Studies with Multiple Strategies and Prospects

Marine microorganisms produce a series of promising enzymes that have been widely used or are potentially valuable for our daily life. Both classic and newly developed biochemistry technologies have been broadly used to study marine and terrestrial microbiological enzymes. In this brief review, we provide a research update and prospects regarding regulatory mechanisms and related strategies of acyl-homoserine lactones (AHL) lactonase, which is an important but largely unexplored enzyme. We also detail the status and catalytic mechanism of the main types of polysaccharide-degrading enzymes that broadly exist among marine microorganisms but have been poorly explored. In order to facilitate understanding, the regulatory and synthetic biology strategies of terrestrial microorganisms are also mentioned in comparison. We anticipate that this review will provide an outline of multiple strategies for promising marine microbial enzymes and open new avenues for the exploration, engineering and application of various enzymes.

Bacterial and Archaeal α-Amylases: Diversity and Amelioration of the Desirable Characteristics for Industrial Applications

Industrial enzyme market has been projected to reach US$ 6.2 billion by 2020. Major reasons for continuous rise in the global sales of microbial enzymes are because of increase in the demand for consumer goods and biofuels. Among major industrial enzymes that find applications in baking, alcohol, detergent, and textile industries are α-amylases. These are produced by a variety of microbes, which randomly cleave α-1,4-glycosidic linkages in starch leading to the formation of limit dextrins. α-Amylases from different microbial sources vary in their properties, thus, suit specific applications. This review focuses on the native and recombinant α-amylases from bacteria and archaea, their production and the advancements in the molecular biology, protein engineering and structural studies, which aid in ameliorating their properties to suit the targeted industrial applications.

Activities of amylase, proteinase, and lipase enzymes from Lactococcus chungangensis and its application in dairy products

Several enzymes are involved in the process of converting milk to lactic acid and coagulated milk to curd and, therefore, are important in dairy fermented products. Amylase, proteinase, and lipase are enzymes that play an important role in degrading milk into monomeric molecules such as oligosaccharides, amino acids, and fatty acids, which are the main molecules responsible for flavors in cheese. In the current study, we determined the amylase, proteinase, and lipase activities of Lactococcus chungangensis CAU 28(T), a bacterial strain of nondairy origin, and compared them with those of the reference strain, Lactococcus lactis ssp. lactis KCTC 3769(T), which is commonly used in the dairy industry. Lactococcus chungangensis CAU 28(T) and L. lactis ssp. lactis KCTC 3769(T) were both found to have amylase, proteinase, and lipase activities in broth culture, cream cheese, and yogurt. Notably, the proteinase and lipase activities of L. chungangensis CAU 28(T) were higher than those of L. lactis ssp. lactis KCTC 3769(T), with proteinase activity of 10.50 U/mL in tryptic soy broth and 8.64 U/mL in cream cheese, and lipase activity of 100 U/mL of tryptic soy broth, and 100 U/mL of cream cheese. In contrast, the amylase activity was low, with 5.28 U/mL in tryptic soy broth and 8.86 U/mL in cream cheese. These enzyme activities in L. chungangensis CAU 28(T) suggest that this strain has potential to be used for manufacturing dairy fermented products, even though the strain is of nondairy origin.