This study investigated the effects of fermentable dietary fiber derived from high-amylose wheat (HAW) flour on the intestinal environment using an in vitro fecal fermentation assay and a randomized, double-blind, parallel-group clinical trial. Digested HAW flour was fractionated into total dietary fiber (TDF), resistant starch (RS), and non-RS dietary fiber (DF-RS) fractions. Fecal culture tests were used to quantify short-chain fatty acid (SCFA) production and microbiota composition after cultivation. In the randomized, double-blind, parallel-group trial, 76 healthy adults consumed HAW-containing food (dietary fiber: 5.5 g/day, RS: 2.9 g/day) or control food (dietary fiber: 0.7 g/day, RS: n.d.) for 2 weeks. Both RS and DF-RS increased SCFA production, with TDF having even stronger effects, suggesting enhanced fermentability in the presence of multiple types of fermentable dietary fibers. In the human trial, HAW-containing food intake did not significantly alter bowel movement frequency compared with the control. However, HAW-containing food consumption significantly reduced the levels of p-cresol, a representative gut-derived proteolytic metabolite linked to intestinal dysbiosis. No significant differences were observed in other secondary endpoints. Intake of HAW-derived foods appears to promote SCFA production and improve the intestinal environment by reducing p-cresol accumulation. Overall, these results highlight HAW flour as a practical prebiotic ingredient that helps support gut health.

This study aimed to evaluate the gut-regulating effects of wheat-derived resistant starch. A randomized, double-blind, placebo-controlled crossover study was conducted with 46 healthy Japanese adults. They were divided into 2 groups, consuming 3.26 g/day of wheat-derived resistant starch and a control food for 4 weeks each, separated by a 4-week washout period. There were no significant differences observed in the primary endpoint of defecation frequency. However, subgroup analysis showed significant improvements in bowel movements for participants who felt a strong sensation of incomplete evacuation. No gut-regulating effects were noted in other subgroups and secondary endpoints. The intake of 3.26 g/day of resistant starch was safe with no overall efficacy observed. Increased stool frequency was observed in participants with less frequent bowel movements and a strong feeling of incomplete evacuation, but no effects were confirmed in other subgroup analyses. No significant changes were observed at secondary endpoints (UMIN ID: UMIN000052543).

Background: PCR-based genetic testing of agricultural products and foods is widely used for detecting various analytical targets such as genetically modified organisms and food allergens. However, it is difficult to obtain accurate genetic testing results from processed foods because DNA is fragmented by heat and pressure during food processing. Thus, we previously developed an analytical method to quantitatively evaluate the degree of DNA fragmentation for the purpose of QC of genetic testing for processed foods. Objective: Our previous analytical method requires four PCR primer sets, resulting in high reagent costs and heavy analytical workloads. Therefore, we attempted to develop an easy-to-use test kit for quantifying the degree of DNA fragmentation and to evaluate its analytical performance. Methods: To simplify the analysis procedure, we used only two primer sets. In addition, no-fragmentation control templates were prepared to obtain stable measurement results. The precision of the simplified analysis was evaluated through blind tests between laboratories. Results: It was confirmed that plant species and extracted DNA concentrations had little effect on analysis with the newly developed test kit. In addition, the analytical values indicating the degree of DNA fragmentation exhibited small variability between laboratories. Conclusion: We confirmed the high practicality of the developed test kit. Because DNA fragmentation in cells is a universal phenomenon, we anticipate that the test kit will be used not only for QC of genetic testing but also for food testing, medical diagnostics, and other applications in a range of fields. Highlights: The newly developed test kit enables quantitative evaluation of the degree of DNA fragmentation in a simple manner.

Background: A wide range of foods containing genetically modified organisms (GMOs) are commercially available. To verify the accuracy of GMO labeling, real-time PCR is used to quantify GMO content in raw materials. However, DNA fragmentation during food processing can introduce analytical bias, making it difficult to accurately assess GMO content in processed foods. Objective: This study aimed to establish a method to accurately evaluate food labeling suitability by inferring the GMO content at the raw material stage from the measurement results of processed foods. Methods: Model processed foods (heat-treated soybeans) containing GM events were prepared and analyzed using a GMO quantification method incorporating taxon-specific real-time PCR with longer amplicons. Results: We observed that the calculated GMO content increased with the length of the amplicon used in the taxon-specific PCR assay. This finding indicates that GMO content can be artificially influenced by modifying the amplicon size. When a longer amplicon was deliberately employed, the GMO content calculated for the processed food always exceeded that of the raw material. Conclusions: The use of longer amplicons in taxon-specific PCR can lead to an overestimation of GMO content at the raw material stage based on the measurements from processed foods. If the overestimated value remains below the labeling threshold, the appropriateness of GMO labeling can still be confirmed. The proposed method offers a simplified and practical approach for use in routine inspections. Highlights: The developed method enables direct analysis of processed foods to assess GMO labeling appropriateness. It eliminates the need to obtain raw materials or conduct multiple analyses. The approach simplifies GMO quantification in inspection laboratories by reducing procedural complexity.