Optimization of leucrose production by dextransucrase from Streptococcus mutans and its application as an adipogenesis regulator

Differentiated digestion resistance and physicochemical properties of linear and α-1,2/α-1,3 branched isomaltodextrins prepared by 4,6-α-glucanotransferase and branching sucrases

Isomaltodextrins (IMDs) are starch-based dietary fibers (DF) prepared enzymatically, which show great potential as a functional food ingredient. In this study, a series of novel IMDs with diverse structures were generated by 4,6-α-glucanotransferase GtfBΔN from Limosilactobacillus fermentum NCC 3057, combined with two α-1,2 and α-1,3 branching sucrases. Results indicated that α-1,2 and α-1,3 branching significantly improved the DF contents of α-1,6 linear products up to 60.9-62.8%. When altering the ratios of [sucrose]/[maltodextrin], IMDs containing 25.8-89.0% α-1,6 bonds, 0-59.6% α-1,2 bonds and 0-35.1% α-1,3 bonds and Mw ranged from 1967 to 4876 Da were obtained. Physicochemical property analysis showed that grafting with α-1,2 or α-1,3 single glycosyl branches can improve the solubility of the α-1,6 linear product, in which α-1,3 branched products were better. Moreover, α-1,2 or α-1,3 branching did no effect on the viscosity of the products but Mw did, the larger Mw the greater viscosity. In addition, α-1,6 linear and α-1,2 or α-1,3 branched IMDs all exhibited strong acid-heating stabilities, freeze-thaw stabilities, and good resistance to browning caused by the Maillard reaction. Branched IMDs showed excellent storage stabilities at room temperature for one year at a concentration of 60%, whereas 45% α-1,6 linear IMD precipitated quickly within 12 h. Most importantly, α-1,2 or α-1,3 branching remarkably increased the contents of resistant starch in the α-1,6 linear IMDs to 74.5-76.8%. These clear qualitative assessments demonstrated the outstanding processing and application properties of the branched IMDs and were expected to provide valuable perspectives toward the technological innovation of functional carbohydrates.

Effects of Natural Alternative Sweeteners on Metabolic Diseases

The rising prevalence of obesity and diabetes is a significant health concern both in globally and is now regarded as a worldwide epidemic. Added sugars like sucrose and high-fructose corn syrup (HFCS) are a major concern due to their link with an increased incidence of diet-induced obesity and diabetes. The purpose of this review is to provide insight into the effects of natural sweeteners as alternatives to sucrose and HFCS, which are known to have negative impacts on metabolic diseases and to promote further research on sugar consumption with a focus on improving metabolic health. The collective evidences suggest that natural alternative sweeteners have positive impacts on various markers associated with obesity and diabetes, including body weight gain, hepatic fat accumulation, abnormal blood glucose or lipid homeostasis, and insulin resistance. Taken together, natural alternative sweeteners can be useful substitutes to decrease the risk of obesity and diabetes compared with sucrose and HFCS.

Comprehensive utilization of sucrose resources via chemical and biotechnological processes: A review

Sucrose, one of the most widespread disaccharides in nature, has been available in daily human life for many centuries. As an abundant and cheap sweetener, sucrose plays an essential role in our diet and the food industry. However, it has been determined that many diseases, such as obesity, diabetes, hyperlipidemia, etc., directly relate to the overconsumption of sucrose. It arouses many explorations for the conversion of sucrose to high-value chemicals. Production of valuable substances from sucrose by chemical methods has been studied since a half-century ago. Compared to chemical processes, biotechnological conversion approaches of sucrose are more environmentally friendly. Many enzymes can use sucrose as the substrate to generate functional sugars, especially those from GH68, GH70, GH13, and GH32 families. In this review, enzymatic catalysis and whole-cell fermentation of sucrose for the production of valuable chemicals were reviewed. The multienzyme cascade catalysis and metabolic engineering strategies were addressed.

Neohesperidin Dihydrochalcone and Neohesperidin Dihydrochalcone-O-Glycoside Attenuate Subcutaneous Fat and Lipid Accumulation by Regulating PI3K/AKT/mTOR Pathway In Vivo and In Vitro

Neohesperidin dihydrochalcone (NHDC), a semi-natural compound from bitter orange, is an intense sweetener. The anti-obesity effects of NHDC and its glycosidic compound, NHDC-O-glycoside (GNHDC), were investigated. C57BLKS/J db/db mice were supplemented with NHDC or GNHDC (100 mg/kg b.w.) for 4 weeks. Body weight gain, subcutaneous tissues, and total adipose tissues (sum of perirenal, visceral, epididymal, and subcutaneous adipose tissue) were decreased in the NHDC and GNHDC groups. Fatty acid uptake, lipogenesis, and adipogenesis-related genes were decreased, whereas β-oxidation and fat browning-related genes were up-regulated in the sweetener groups. Furthermore, both sweeteners suppressed the level of triacylglycerol accumulation, lipogenesis, adipogenesis, and proinflammatory cytokines in the 3T3-L1 cells. The PI3K/AKT/mTOR pathway was also down-regulated, and AMP-acttvated protein kinase (AMPK) was phosphorylated in the treatment groups. These results suggest that NHDC and GNHDC inhibited subcutaneous fat and lipid accumulation by regulating the PI3K/AKT/mTOR pathway and AMPK-related lipogenesis and fat browning.

Increasing the dietary fiber contents in isomaltooligosaccharides by dextransucrase reaction with sucrose as a glucosyl donor

Isomaltooligosaccharides (IMOs) have been widely used as alternative sweeteners owing to their stabilities, low calorigenic, and prebiotic properties. The aim of this research was to improve the functionality of conventionally produced IMOs by increasing dietary fiber (DF) content with newly synthesized α-(1,6)-linkages through the dextransucrase reaction. To optimize the reaction conditions, various combinations of IMO and sucrose concentrations were applied as acceptor and donor molecules, respectively. Soluble DF content in the enzymatically-modified IMOs increased significantly with the initial substrate mixture of 10 % sucrose and 20 % IMOs; both DF and IMO contents increased to 35 % and 54 %, respectively. It was clearly suggested a simple dextransucrase-involved bioprocess could be applied to increase the DF content to the IMOs produced via a conventional process without scarifying the original IMO contents. Thus, it will be expected that the DF-enhanced IMO products are potentially applicable as functional ingredients as sugar substitutes in the food industry.

Versatile biotechnological applications of amylosucrase, a novel glucosyltransferase

Amylosucrase (AS; EC 2.4.1.4) is an enzyme that has great potential in the biotechnology and food industries, due to its multifunctional enzyme activities. It can synthesize α-1,4-glucans, like amylose, from sucrose as a sole substrate, but importantly, it can also utilize various other molecules as acceptors. In addition, AS produces sucrose isomers such as turanose and trehalulose. It also efficiently synthesizes modified starch with increased ratios of slow digestive starch and resistant starch, and glucosylated functional compounds with increased water solubility and stability. Furthermore, AS produces turnaose more efficiently than other carbohydrate-active enzymes. Amylose synthesized by AS forms microparticles and these can be utilized as biocompatible materials with various bio-applications, including drug delivery, chromatography, and bioanalytical sciences. This review not only compares the gene and enzyme characteristics of microbial AS, studied to date, but also focuses on the applications of AS in the biotechnology and food industries.

Sucrose isomers as alternative sweeteners: properties, production, and applications

In the daily diet, sweeteners play an indispensable role. Among them, sucrose, a widely occurring disaccharide in nature, is a commonly used sweetener. However, the intake of sucrose can cause a rapid increase in blood glucose, which leads to a number of health problems. Therefore, there is an urgent need for possible alternatives to sucrose. Currently, four naturally occurring sucrose isomers, trehalulose, turanose, leucrose, and isomaltulose are considered to be possible alternatives to sucrose due to their suitable sweetness, potential physiological benefits, and feasible production processes. This review covers the properties of these alternative sweeteners, including their structure, sweetness, hydrolysis rate, toxicology, and cariogenicity, and exhibits their potential applications in chronic diseases management, anti-inflammatory supplement, prebiotic dietary supplement, and stabilizing agent. The biosynthesis of these sucrose isomers using carbohydrate-active enzymes and their industrial production processes are also systematically summarized.

Leucrose, a Sucrose Isomer, Suppresses Hepatic Fat Accumulation by Regulating Hepatic Lipogenesis and Fat Oxidation in High-fat Diet-induced Obese Mice

Obesity is currently one of the most serious public health problems and it can lead to numerous metabolic diseases. Leucrose, d-glucopyranosyl-α-(1-5)-d-fructopyranose, is an isoform of sucrose and it is naturally found in pollen and honey. The aim of this study was to investigate the effect of leucrose on metabolic changes induced by a high-fat diet (HFD) that lead to obesity. C57BL/6 mice were fed a 60% HFD or a HFD with 25% (L25) or 50% (L50) of its total sucrose content replaced with leucrose for 12 weeks. Leucrose supplementation improved fasting blood glucose levels and hepatic triglyceride content. In addition, leucrose supplementation reduced mRNA levels of lipogenesis-related genes, including peroxisome proliferator-activated receptor γ, sterol regulatory element binding protein 1C, and fatty acid synthase in HFD mice. Conversely, mRNA levels of β oxidation-related genes, such as carnitine palmitoyltransferase 1A and acyl CoA oxidase, returned to control levels with leucrose supplementation. Taken together, these results demonstrated the therapeutic potential of leucrose to prevent metabolic abnormalities by mediating regulation of plasma glucose level and hepatic triglyceride accumulation.