Designing a Specific Pretreatment on Corn Starch to Facilitate Enzymatic Rearrangement of Glycosidic Bonds for Efficiently Reducing Starch Digestibility.

Bacterial 1,4-α-glucan branching enzymes (GBEs) provide a viable strategy for glycosidic bond rearrangement in starch and regulation of its digestion rate. However, the exponential increase in paste viscosity during starch gelatinization has a detrimental effect on the catalytic action of GBEs, thereby limiting productivity and product performance. Here, we designed an enzymatic treatment on corn starch granules by the GBE from Rhodothermus obamensis STB05 (Ro-GBE) prior to the glycosidic bond rearrangement of gelatinized starch catalyzed using the GBE from Geobacillus thermoglucosidans STB02 (Gt-GBE). Specifically, a moderate amount of Ro-GBE was required for the pretreatment stage. The dual GBE modification process enabled the treatment of more concentrated starch slurry (up to 20%, w/w) and effectively reduced starch digestibility. The resulting product contained a rapidly digestible starch fraction of 66.0%, which was 11.4% lower than that observed in the single Gt-GBE-modified product. The mechanistic investigation showed that the Ro-GBE treatment promoted swelling and gelatinization of starch granules, reduced starch paste viscosity, and increased the mobility of water molecules in the starch paste. It also created a preferable substrate for Gt-GBE. These changes improved the transglycosylation efficiency of Gt-GBE. These findings provide useful guidance for designing an efficient process to regulate starch digestibility.

Mental health literacy questionnaire-short version for adults (MHLq-SVa): validation study in China, India, Indonesia, Portugal, Thailand, and the United States.

BACKGROUND: Mental Health Literacy (MHL) has become a focus of research in recent decades, as a prerequisite for early identification and intervention for mental health problems. Although several instruments have been developed for assessing MHL, there is a need for brief and psychometrically sound measures to capture important aspects of MHL in large and diverse adult samples. The present study aimed to: (1) provide a revised and shorter version of a previously validated questionnaire for assessing MHL; and (2) examine the psychometric properties of the MHLq-SVa in student samples from six different countries (China, India, Indonesia, Portugal, Thailand, and United States). METHODS: The study involved 2180 senior school and undergraduate students, aged between 17 and 25 years old, from China, India, Indonesia, Portugal, Thailand, and the United States. Participants responded to the Mental Health Literacy Questionnaire for young adults (MHLq-ya), in their native language, following its translation and adaptation for each culture. The MHLq-ya comprises 29 items, organized into four dimensions: Knowledge of mental health problems; Erroneous beliefs/stereotypes; First-aid skills and help-seeking behavior; Self-help strategies. Confirmatory factor analyses and internal consistency analyses were performed on the combined data. RESULTS: Data from the different countries supported a shorter version of the questionnaire (MHLq-SVa), composed of 16 items that fit with previously defined dimensions. Internal consistency and between-factor correlations further supported the adequacy of the instrument's psychometric properties. CONCLUSION: The study provided preliminary support for the construct validity and reliability of the MHLq-SVa as a measure for assessing MHL in young adults from six different countries and languages. Future studies are needed to further validate the measure and undertake multicultural comparisons of MHL in diverse samples from around the globe.

Short-Clustered Maltodextrin Activates Ileal Glucose-Sensing and Induces Glucagon-like Peptide 1 Secretion to Ameliorate Glucose Homeostasis in Type 2 Diabetic Mice.

Reconstructing molecular structure is an effective approach to attenuating glycemic response to starch. Previously, we rearranged α-1,4 and α-1,6-glycosidic bonds in starch molecules to produce short-clustered maltodextrin (SCMD). The present study revealed that SCMD slowly released glucose until the distal ileum. The activated ileal glucose-sensing enabled SCMD to be a potent inducer for glucagon-like peptide-1 (GLP-1). Furthermore, SCMD was found feasible to serve as the dominant dietary carbohydrate to rescue mice from diabetes. Interestingly, a mixture of normal maltodextrin and resistant dextrin (MD+RD), although it caused an attenuated glycemic response similar to that of SCMD, failed to ameliorate glucose homeostasis because it hardly induced GLP-1 secretion. The serum GLP-1 levels seen in MD+RD-fed mice (5.25 ± 1.51 pmol/L) were significantly lower than those seen in SCMD-fed mice (8.25 ± 2.01 pmol/L, p < 0.05). Further investigation revealed that the beneficial effects of SCMD could be abolished by a GLP-1 receptor (GLP-1R) antagonist. These results identify GLP-1R signaling as a critical contributor to SCMD-exerted health benefits and highlight the role of ileal glucose-sensing in designing dietary carbohydrates.

Perspectives on evaluating health effects of starch: Beyond postprandial glycemic response.

Starch is an important dietary carbohydrate in the human diet and is greatly associated with human health. The health effects of starch are classically evaluated by postprandial glycemic response. However, glycemic response is the test result of blood glucose level and sometimes fails to perfectly describe the health effects exerted by starch. Therefore, other factors, besides glycemic response, merit consideration. Herein, we endeavor to provide some insights into the description of health effects exerted by starch. For this purpose, we summarize advances in recent studies to support the crucial roles of glucose kinetics, insulin response, and gut hormones release. A moderate postprandial insulin response and an enhanced release of several specific gut hormones are critical characteristics of a healthier starch, such as those slowly digested till the distal ileum. It is also hoped that further studies can develop feasible methods to produce tailor-made starches with individualized health effects.

Two 1,4-α-glucan branching enzymes successively rearrange glycosidic bonds: A novel synergistic approach for reducing starch digestibility.

Enzymatically rearranging α-1,4 and α-1,6 glycosidic bonds in starch is a green approach to regulating its digestibility. A two-step modification process successively catalyzed by 1,4-α-glucan branching enzymes (GBEs) from Rhodothermus obamensi STB05 (Ro-GBE) and Geobacillus thermoglucosidans STB02 (Gt-GBE) was investigated as a strategy to reduce the digestibility of corn starch. This dual GBE modification process caused a reduction of 25.8 % in rapidly digestible starch fraction in corn starch, which were more effective than single GBE-catalyzed modification with the same duration. Structural analysis indicated that the dual GBE modified product contained higher branching density, more abundant short branches, and shorter external chains than those in single GBE-modified product. These results demonstrated that a moderate Ro-GBE treatment prior to starch gelatinization caused several suitable alterations in starch molecules, which promoted the transglycosylation efficiency of the following Gt-GBE treatment. This dual GBE-catalyzed modification process offered an efficient strategy for regulating starch digestibility.

An Innovative Short-Clustered Maltodextrin as Starch Substitute for Ameliorating Postprandial Glucose Homeostasis.

Dietary starch is usually associated with elevated postprandial glycemic response. This is a potential risk factor of type 2 diabetes. Here, a 1,4-α-glucan branching enzyme (GBE) was employed to reassemble α-1,4 and α-1,6 glycosidic bonds in starch molecules. Structural characterization showed that GBE-catalyzed molecular reassembly created an innovative short-clustered maltodextrin (SCMD), which showed a dense internal framework along with shortened external chains. Such short-clustered molecules obstructed digestive enzymes attack and displayed dramatically reduced digestibility. Therefore, SCMD was served as a dietary starch substitute to improve postprandial glucose homeostasis. A 22.3% decrease in glycemic peak was therefore detected in ICR mice following SCMD intake (10.7 mmol/L), compared with that in the control (13.8 mmol/L). Moreover, an attenuated insulin response (40.5% lower than that in control) to SCMD intake was regarded suitable for diabetes management. These novel discoveries demonstrate that enzymatically rebuilding starch molecules may be a meaningful strategy for diabetes management.

Novel Short-Clustered Maltodextrin as a Dietary Starch Substitute Attenuates Metabolic Dysregulation and Restructures Gut Microbiota in db/db Mice.

Molecular structure of starch in daily diet is closely associated with diabetes management. By enzymatically reassembling α-1,4 and α-1,6 glycosidic bonds in starch molecules, we have synthesized an innovative short-clustered maltodextrin (SCMD) which slowly releases glucose during digestion. Here, we investigated the potential benefits of the SCMD-containing diet using diabetic db/db mice. As compared to a diet with normal starch, this dietary style greatly attenuated hyperglycemia and repaired symptoms associated with diabetes. Additionally, in comparison with acarbose (an α-glucosidase inhibitor) administration, the SCMD-containing diet more effectively accelerated brown adipose activation and improved energy metabolism of db/db mice. Furthermore, the SCMD-containing diet was a more suitable approach to improving the intestinal microflora than acarbose administration, especially the proliferation of Mucispirillum, Akkermansia, and Bifidobacterium. These results reveal a novel strategy for diabetes management based on enzymatically rebuilding starch molecules in the daily diet.