Potato Resistant Starch Type 1 Promotes Obesity Linked with Modified Gut Microbiota in High-Fat Diet-Fed Mice.

Obesity has become a major disease that endangers human health. Studies have shown that dietary interventions can reduce the prevalence of obesity and diabetes. Resistant starch (RS) exerts anti-obesity effects, alleviates metabolic syndrome, and maintains intestinal health. However, different RS types have different physical and chemical properties. Current research on RS has focused mainly on RS types 2, 3, and 4, with few studies on RS1. Therefore, this study aimed to investigate the effect of RS1 on obesity and gut microbiota structure in mice. In this study, we investigated the effect of potato RS type 1 (PRS1) on obesity and inflammation. Mouse weights, as well as their food intake, blood glucose, and lipid indexes, were assessed, and inflammatory factors were measured in the blood and tissues of the mice. We also analyzed the expression levels of related genes using PCR, with 16S rRNA sequencing used to study intestinal microbiota changes in the mice. Finally, the level of short-chain fatty acids was determined. The results indicated that PRS1 promoted host obesity and weight gain and increased blood glucose and inflammatory cytokine levels by altering the gut microbiota structure.

Effect of Pullulanase Debranching Time Combined with Autoclaving on the Structural, Physicochemical Properties, and In Vitro Digestibility of Purple Sweet Potato Starch.

The effects of pullulanase debranching combined with autoclaving (PDA) at various debranching times (0 h, 5 h, 10 h, 15 h, 20 h, and 25 h) and 121 °C/20 min of autoclave treatment on the structural and physicochemical characteristics of purple sweet potato (Jinshu No.17) starch were investigated. The results indicated that the native starch (NS) was polygonal, round, and bell-shaped with smooth surfaces. After debranching treatment, the surface of the starch samples became rough and irregular. The molecular weight became smaller after treatments. X-ray diffraction C-type pattern was transformed into a B-type structure in treated samples with increased relative crystallinity. 13C NMR indicated an increased propensity for double helix formation and new shift at C1, 3, 5 region compared to NS. The apparent amylose content was 21.53% in the NS. As the swelling power decreased, the percentage of soluble solids increased and different thermal properties were observed. A higher yield of the resistant starch (RS) was observed in all treated starch except PDA 25 h. The findings of our study reveal that a combination of pullulanase debranching time (15 h) and autoclaving (121 °C for 20 min) is a great technique that can be used to produce a higher amount of resistant starch in the Jinshu No.17 starch.

Potato resistant starch inhibits diet-induced obesity by modifying the composition of intestinal microbiota and their metabolites in obese mice.

Potato resistant starch type 3 (PRS) is helpful for weight-loss. To investigate the regulatory effects of PRS on high-fat diet (HFD)-induced obesity, different doses of PRS (5%, 15% and 25%) were fed to mice for 12 weeks. Metabolic syndrome related to obesity, intestinal microbiota composition and its metabolites as well as the relationship among them were studied. Results showed that PRS could regulate HFD-induced metabolic syndrome in a dose dependent manner; promote the proliferation of intestinal cells and expression of tight junction proteins, such as Occludin and zonula occludens (ZO)-1; reduce the Firmicutes/Bacteroidetes (F/B) rate; regulate the relative abundance of intestinal microbiota, such as Bifidobacterium, Ruminococcus, Bacteroides and Coprococcus; and promote the production of microbial metabolites, such as propionic acid and acetic acid. Besides, the alteration in the intestinal microbiota composition and metabolites were significantly correlated. It could be concluded that propionic acid and acetic acid were the two dominant metabolites of Bifidobacterium, Ruminococcus, Bacteroides, and Coprococcus, which contributed to the anti-obesity potential of PRS, metabolic syndrome alleviation, and intestinal barrier dysfunction.

Insights into the structure and conformation of potato resistant starch (type 2) using asymmetrical flow field-flow fractionation coupled with multiple detectors.

Insight into the structure and conformation characteristics of starch that influence its enzyme susceptibility is import for its potential application. In this study, the capacity of asymmetrical flow field-flow fractionation (AF4) coupled online with multi-angle light scatting (MALS) and differential refractive index (dRI) detectors (AF4-MALS-dRI) for monitoring of change in structure and conformation of potato starch during enzymatic hydrolysis was evaluated. The dissolution behavior of potato resistant starch (type 2) (PRS) was investigated. The effect of incubation time and amyloglucosidase concentration on the structure and conformation of potato starch was studied. The apparent density and the ratio of Rg (radius of gyration) to Rh (hydrodynamic radius) obtained from AF4-MALS-dRI were proven to be important parameters as they offer an insight into conformation of PRS at molecular level. Results suggested that gelatinization process made potato amylose molecules have a loose and random coil conformation which could contribute to an acceleration of enzymatic hydrolysis of potato starch. Furthermore, an intermediate with an elongated branched conformation was found between amylose and amylopectin populations, which may play a role in digestion property of potato starch. The results demonstrated that AF4-MALS-dRI is a powerful tool for better understanding of conformation of PRS.

Comparative Assessment of the Bioremedial Potentials of Potato Resistant Starch-Based Microencapsulated and Non-encapsulated Lactobacillus plantarum to Alleviate the Effects of Chronic Lead Toxicity.

Lead (Pb) is a well-recognized and potent heavy metal with non-biodegradable nature and can induce the oxidative stress, degenerative damages in tissues, and neural disorders. Certain lactic acid bacterial strains retain the potential to mitigate the lethal effects of Pb. The present work was carried out to assess the Pb bio-sorption and tolerance capabilities of Lactobacillus plantarum spp. Furthermore, potato resistant starch (PRS)-based microencapsulated and non-encapsulated L. plantarum KLDS 1.0344 was utilized for bioremediation against induced chronic Pb toxicity in mice. The experimental mice were divided into two main groups (Pb exposed and non-Pb exposed) and, each group was subsequently divided into three sub groups. The Pb exposed group was exposed to 100 mg/L Pb(NO3)2 via drinking water, and non-Pb exposed group was supplied with plain drinking water during 7 weeks prolonged in vivo study. The accumulation of Pb in blood, feces, renal, and hepatic tissues and its pathological damages were analyzed. The effect of Pb toxicity on the antioxidant enzyme capabilities in blood, serum, as well as, on levels of essential elements in tissues was also calculated. Moreover, KLDS 1.0344 displayed remarkable Pb binding capacity 72.34% and Pb tolerance (680 mg/L). Oral administration of both non- and PRS- encapsulated KLDS 1.0344 significantly provided protection against induced chronic Pb toxicity by increasing fecal Pb levels (445.65 ± 22.28 µg/g) and decreasing Pb in the blood up to 137.63 ± 2.43 µg/L, respectively. KLDS 1.0344 microencapsulated with PRS also relieved the renal and hepatic pathological damages and improved the antioxidant index by inhibiting changes in concentrations of glutathione peroxidase, glutathione, superoxide dismutase, malondialdehyde, and activated oxygen species, which were affected by the Pb exposure. Overall, our results suggested that L. plantarum KLDS 1.0344 either in free or encapsulated forms hold the potentiality to deliver a dietetic stratagem against Pb lethality.