In vitro evaluation of fermentation characteristics of type 3 resistant starch

Type 3 resistant starch from Canna edulis reduce lipid levels in patients with mild hyperlipidemia through altering gut microbiome: A double- blind randomized controlled trial

Type 3 resistant starch from Canna edulis (Ce-RS3) is an insoluble dietary fiber which could improve blood lipids in animals, but clinically robust evidence is still lacking. We performed a double-blind randomized controlled trial to assess the effects of Ce-RS3 on lipids in mild hyperlipidemia. One hundred and fifteen patients were included followed the recruitment criteria, and were randomly allocated to receive Ce-RS3 or placebo (native starch from Canna edulis) for 12 weeks (20 g/day). In addition to serum lipids, complete blood counts, serum inflammatory factors, antioxidant indexes, and dietary survey, 16 S rRNA sequencing technique was utilized to analyze the gut microbiota alterations. Targeted quantitative metabolomics (TQM) was used to detect metabolite changes. Compared with the placebo, Ce- RS3 significantly decreased levels of total cholesterol, lowdensity lipoprotein cholesterol, and non-high-density lipoprotein cholesterol, and increased the glutathione peroxidase. Based on the 16 S rRNA sequencing, TQM, the correlation analysis, as well as the Kyoto Encyclopedia of Genes (KEGG) and Genomes and Human Metabolome Database (HMDB) analysis, we found that Ce-RS3 could increase the abundances of genera Faecalibacterium and Agathobacter, while reduce the abundances of genera norank_f_Ruminococcaceae and Christensenellaceae_R-7_ group to regulate phenylalanine metabolism, which could reduce the fatty acid biosynthesis and fatty acid elongation in the mitochondria to lower blood lipids. Conclusively, we firstly confirmed the feasibility of Ce-RS3 for clinical application, which presents a novel, effective therapy for the mild hyperlipidemia. (Chictr. org. cn. Clinical study on anti-mild hyperlipidemia of Canna edulis RS3 resistant starch, ID Number: ChiCTR2200062871).

Advancements in enhancing resistant starch type 3 (RS3) content in starchy food and its impact on gut microbiota: A review

Resistant starch type 3 (RS3), often found in cooked starchy food, has various health benefits due to its indigestible properties and physiological functions such as promoting the abundance of gut beneficial microbial flora and inhibiting the growth of intestinal pathogenic bacteria. However, it is challenging to develop starchy food with high RS3 content. This review aims to provide a detailed overview of current advancements to enhance RS3 content in starchy food and its effects of RS3 on gut microbiota. These approaches include breeding high-amylose cereals through gene editing techniques, processing, enzyme treatments, storage, formation of RS3 nanoparticles, and the incorporation of bioactive compounds. The mechanisms, specific conditions, advantages, and disadvantages associated with each approach and the potential effects of RS3 prepared by different methods on gut microbiota are summarized. In conclusion, this review contains important information that aims to provide guidelines for developing an efficient RS3 preparation process and promote the consumption of RS3-enriched starchy foods to improve overall health outcomes.

Structure properties of Canna edulis RS3 (double enzyme hydrolysis) and RS4 (OS-starch and cross-linked starch): Influence on fermentation products and human gut microbiota

This study investigated the in vitro fermentation characteristics of different structural types of Canna edulis resistant starch (RS). RS3 was prepared through a double enzyme hydrolysis method, and RS4 (OS-starch and cross-linked starch) was prepared using octenyl succinic anhydride and sodium trimetaphosphate/sodium tripolyphosphate, respectively. The RS3 and RS4 samples were structurally analyzed using scanning electron microscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction analysis. This was followed by in vitro fermentation experiments. The results revealed microstructure differences in the two groups of starch samples. Compared to native starch, RS3 and RS4 exhibited a lower degree of order and endothermic energy, with lower crystallinity (RS3: 29.59 ± 1.11 %; RS4 [OS-starch]: 28.01 ± 1.32 %; RS4 [cross-linked starch]: 30.44 ± 1.73 %) than that in native starch (36.29 ± 0.89 %). The RS content was higher in RS3 (63.40 ± 2.85 %) and RS4 (OS-starch: 71.21 ± 1.28 %; cross-linked starch: 74.33 ± 0.643 %) than in native starch (57.71 ± 2.95 %). RS3 and RS4 exhibited slow fermentation rates, promoting the production of short-chain fatty acids. RS3 and cross-linked starch significantly increased the production of acetate and butyrate. Moreover, RS3 significantly promoted the abundance of Lactobacillus, while OS-starch and cross-linked starch significantly enhanced the abundance of Dorea and Coprococcus, respectively. Hence, the morphological structure and RS content of the samples greatly influenced the fermentation rate. Moreover, the different varieties of RS induced specific gut microbial regulation. Hence, they show potential applications in functional foods for tailored gut microbiota management.

Functionalization Methods of Starch and Its Derivatives: From Old Limitations to New Possibilities

It has long been known that starch as a raw material is of strategic importance for meeting primarily the nutritional needs of people around the world. Year by year, the demand not only for traditional but also for functional food based on starch and its derivatives is growing. Problems with the availability of petrochemical raw materials, as well as environmental problems with the recycling of post-production waste, make non-food industries also increasingly interested in this biopolymer. Its supporters will point out countless advantages such as wide availability, renewability, and biodegradability. Opponents, in turn, will argue that they will not balance the problems with its processing and storage and poor functional properties. Hence, the race to find new methods to improve starch properties towards multifunctionality is still ongoing. For these reasons, in the presented review, referring to the structure and physicochemical properties of starch, attempts were made to highlight not only the current limitations in its processing but also new possibilities. Attention was paid to progress in the non-selective and selective functionalization of starch to obtain materials with the greatest application potential in the food (resistant starch, dextrins, and maltodextrins) and/or in the non-food industries (hydrophobic and oxidized starch).

Presence of digestible starch impacts in vitro fermentation of resistant starch

Starch is an important energy source for humans. Starch escaping digestion in the small intestine will transit to the colon to be fermented by gut microbes. Many gut microbes express α-amylases that can degrade soluble starch, but only a few are able to degrade intrinsic resistant starch (RS), which is insoluble and highly resistant to digestion (≥80% RS). We studied the in vitro fermentability of eight retrograded starches (RS-3 preparations) differing in rapidly digestible starch content (≥70%, 35-50%, ≤15%) by a pooled adult faecal inoculum and found that fermentability depends on the digestible starch fraction. Digestible starch was readily fermented yielding acetate and lactate, whereas resistant starch was fermented much slower generating acetate and butyrate. Primarily Bifidobacterium increased in relative abundance upon digestible starch fermentation, whereas resistant starch fermentation also increased relative abundance of Ruminococcus and Lachnospiraceae. The presence of small fractions of total digestible starch (±25%) within RS-3 preparations influenced the fermentation rate and microbiota composition, after which the resistant starch fraction was hardly fermented. By short-chain fatty acid quantification, we observed that six individual faecal inocula obtained from infants and adults were able to ferment digestible starch, whereas only one adult faecal inoculum was fermenting intrinsic RS-3. This suggests that, in contrast to digestible starch, intrinsic RS-3 is only fermentable when specific microbes are present. Our data illustrates that awareness is required for the presence of digestible starch during in vitro fermentation of resistant starch, since such digestible fraction might influence and overrule the evalution of the prebiotic potential of resistant starches.

Type of intrinsic resistant starch type 3 determines in vitro fermentation by pooled adult faecal inoculum

Resistant starch (RS) results in relatively high health-beneficial butyrate levels upon fermentation by gut microbiota. We studied how physico-chemical characteristics of RS-3 influenced butyrate production during fermentation. Six highly resistant RS-3 substrates (intrinsic RS-3, 80-95 % RS) differing in chain length (DPn 16-76), Mw distribution (PI) and crystal type (A/B) were fermented in vitro by pooled adult faecal inoculum. All intrinsic RS-3 substrates were fermented to relatively high butyrate levels (acetate/butyrate ≤ 2.5), and especially fermentation of A-type RS-3 prepared from polydisperse α-1,4 glucans resulted in the highest relative butyrate amount produced (acetate/butyrate: 1). Analysis of the microbiota composition after fermentation revealed that intrinsic RS-3 stimulated primarily Lachnospiraceae, Bifidobacterium and Ruminococcus, but the relative abundances of these taxa differed slightly depending on the RS-3 physico-chemical characteristics. Especially intrinsic RS-3 of narrow disperse Mw distribution stimulated relatively more Ruminococcus. Selected RS fractions (polydisperse Mw distribution) obtained after pre-digestion were fermented to acetate and butyrate (ratio ≤ 1.8) and stimulated Lachnospiraceae and Bifidobacterium. This study indicates that especially the α-1,4 glucan Mw distribution dependent microstructure of RS-3 influences butyrate production and microbiota composition during RS-3 fermentation.

Slow digestion-oriented dietary strategy to sustain the secretion of GLP-1 for improved glucose homeostasis

Dysregulated glucose metabolism is associated with many chronic diseases such as obesity and type 2 diabetes mellitus (T2DM), and strategies to restore and maintain glucose homeostasis are essential to health. The incretin hormone of glucagon-like peptide-1 (GLP-1) is known to play a critical role in regulating glucose homeostasis and dietary nutrients are the primary stimuli to the release of intestinal GLP-1. However, the GLP-1 producing enteroendocrine L-cells are mainly distributed in the distal region of the gastrointestinal tract where there are almost no nutrients to stimulate the secretion of GLP-1 under normal situations. Thus, a dietary strategy to sustain the release of GLP-1 was proposed, and the slow digestion property and dipeptidyl peptidase IV (DPP-IV) inhibitory activity of food components, approaches to reduce the rate of food digestion, and mechanisms to sustain the release of GLP-1 were reviewed. A slow digestion-oriented dietary approach through encapsulation of nutrients, incorporation of viscous dietary fibers, and enzyme inhibitors of phytochemicals in a designed whole food matrix will be implemented to efficiently reduce the digestion rate of food nutrients, potentiate their distal deposition and a sustained secretion of GLP-1, which will be beneficial to improved glucose homeostasis and health.