Justin Carlson

Prebiotic Effects and Fermentation Kinetics of Wheat Dextrin and Partially Hydrolyzed Guar Gum in an In Vitro Batch Fermentation System

Scientific research demonstrates that two indigenous gut bacteria, Lactobacillus and Bifidobacterium can contribute to human health. Although these bacteria can be consumed as probiotics, they can also be produced in the gut by bacteria, and are then called prebiotics. The primary objective of this in vitro study was to quantitatively analyze at the genus level how two dietary fibers, wheat dextrin (WD) and partially hydrolyzed guar gum (PHGG) changed the levels of these two gut bacteria at 12 and 24 h, via real time qualitative polymerase chain reaction (qPCR). Secondary objectives were changes in fecal pH, short chain fatty acids (SCFAs) and total gas volume produced. At 12 h WD was more bifidogenic (9.50 CFU log10/mL) than PHGG (9.30 CFU log10/mL) (p = 0.052), and also at 24 h WD (9.41 CFU log10/mL) compared with PHGG (9.27 CFU log10/mL) (p = 0.043). WD produced less total SCFAs at both 12 and 24 h than PHGG, and produced significantly lower amounts of gas at 12 and 24 h (p < 0.001). Both PHGG and WD also promoted growth of Lactobacilli when measured at 12 and 24 h compared with the 0 h analysis, indicating that both fibers are lactogenic. These results demonstrate the prebiotic effect of WD and PHGG. Based on fermentation kinetics, PHGG is more rapidly fermented than WD, and both fibers show prebiotic effects as early as 12 h.

In vitro analysis of partially hydrolyzed guar gum fermentation differences between six individuals

Partially hydrolyzed guar gum (PHGG) is a fermentable, soluble, non-gelling fiber consumed as both a supplement and ingredient. PHGG supports bifidogenic and lactogenic growth, and increases the concentration of short chain fatty acids (SCFAs) in the distal intestine due to its fermentability. Changes in SCFA development due to the fermentation of dietary fibers in the colon have been widely studied, but there are limited studies analyzing the differences in SCFA development across multiple individuals (ages 23-68) exposed to the same dietary fiber (PHGG). With the six donors analyzed in this study, gas production varied from 59-80 mL/0.5 g fiber at 12 h and 85-93 mL/0.5 g fiber at 24 h between the six donors. At 12 h butyrate concentrations varied from 6.99 μmol mL(-1) to 23.84 μmol mL(-1) and from 8.78 μmol mL(-1) to 22.84 μmol mL(-1) at 24 h. Total SCFA concentration at 24 h ranged from 42.85 μmol mL(-1) to 91.17 μmol mL(-1). The overall average SCFA ratio for the six fecal donors was 30 : 45 : 25 (acetate : propionate : butyrate), which is similar to other fermentable fibers analyzed using in vitro systems. SCFA development in the distal intestine increases the amount of metabolizable energy from the diet, but varies greatly among people based primarily on the composition and changes of their gut microflora. With over a 2-fold difference in SCFA production, significant differences were found among healthy individuals fecal microflora when exposed to PHGG. Donor 6 SCFA concentrations decreased at 24 h, indicating a quicker fermentation process than the other five donors. All SCFAs measured fluctuated greatly among the six individuals within 24 h of analysis. Results of in vitro fermentation analyses are limited by the wide variation found with fecal donor.

Health benefits of fibre, prebiotics and probiotics: a review of intestinal health and related health claims

Gastrointestinal health in regard to the gut microbiome is a rapidly emerging field and has many key components driving its emergence. Fibre, prebiotics and probiotics are all dietary components that can play a critical role in maintaining a healthy gut microflora. Fibre has long been appreciated for its influential role in cardiovascular disease, glycaemic control and weight management through various physiological mechanisms. Prebiotics have been shown to play an influential role in irritable bowel symptoms/disease, colon cancer, cardiovascular disease and overall digestive health. Together, various types of fibres and prebiotics have been targeted and synthesised to influence the gut microbiome, specifically Lactobacillus and Bifidobacterium populations. Lactobacillus spp. and Bifidobacterium spp. are common markers for gut health because they have been shown to down-regulate inflammation in the gastrointestinal tract, alleviate irritable bowel syndrome symptoms, stimulate immune functions, aid in mine...

Prebiotic Dietary Fiber and Gut Health: Comparing the in Vitro Fermentations of Beta-Glucan, Inulin and Xylooligosaccharide

Prebiotic dietary fiber supplements are commonly consumed to help meet fiber recommendations and improve gastrointestinal health by stimulating beneficial bacteria and the production of short-chain fatty acids (SCFAs), molecules beneficial to host health. The objective of this research project was to compare potential prebiotic effects and fermentability of five commonly consumed fibers using an in vitro fermentation system measuring changes in fecal microbiota, total gas production and formation of common SCFAs. Fecal donations were collected from three healthy volunteers. Materials analyzed included: pure beta-glucan, Oatwell (commercially available oat-bran containing 22% oat β-glucan), xylooligosaccharides (XOS), WholeFiber (dried chicory root containing inulin, pectin, and hemi/celluloses), and pure inulin. Oatwell had the highest production of propionate at 12 h (4.76 μmol/mL) compared to inulin, WholeFiber and XOS samples (p < 0.03). Oatwell’s effect was similar to those of the pure beta-glucan samples, both samples promoted the highest mean propionate production at 24 h. XOS resulted in a significant increase in the genus Bifidobacterium after 24 h of fermentation (0 h:0.67 OTUs (operational taxonomic unit); 24 h:5.22 OTUs; p = 0.038). Inulin and WholeFiber increased the beneficial genus Collinsella, consistent with findings in clinical studies. All analyzed compounds were fermentable and promoted the formation of beneficial SCFAs.

Fermentability of Novel Type-4 Resistant Starches in In Vitro System

Resistant starches are non-digestible starches that are fermented in the colon by microbiota. These carbohydrates are prebiotic and can be beneficial to consumer health. Many types of resistant starch exist with varying physical properties that may result in differences in fermentability. The objective of this research project was to compare potential prebiotic effects and fermentability of four novel resistant starches using an in vitro fermentation system and measuring changes in total gas production, pH, and formation of SCFAs (short chain fatty acids). Fecal donations were collected from seven healthy volunteers. Four novel resistant starches, modified potato starch (MPS), modified tapioca starch (MTS), and modified maize starches (MMS-1 and MMS-2), were analyzed and compared to polydextrose and short chain fructooligosaccharides (FOS) as controls. After twenty-four hours of fermentation, MPS and MTS responded similarly in gas production (74 mL; 70.6 mL respectively), pH (5.93; 5.93 respectively), and SCFA production (Acetate: 115; 124, Propionate: 21; 26, Butyrate: 29; 31 μmol/mL respectively). While MMS-1 had similar gas production and individual SCFA production, the pH was significantly higher (6.06). The fermentation of MMS-2 produced the least amount of gas (22 mL), with a higher pH (6.34), and lower acetate production (78.4 μmol/mL). All analyzed compounds were fermentable and promoted the formation of beneficial SCFAs.

Health Effects and Sources of Prebiotic Dietary Fiber

Abstract Prebiotic dietary fibers act as carbon sources for primary and secondary fermentation pathways in the colon, and support digestive health in many ways. Fructooligosaccharides, inulin, and galactooligosaccharides are universally agreed-upon prebiotics. The objective of this paper is to summarize the 8 most prominent health benefits of prebiotic dietary fibers that are due to their fermentability by colonic microbiota, as well as summarize the 8 categories of prebiotic dietary fibers that support these health benefits. Although not all categories exhibit similar effects in human studies, all of these categories promote digestive health due to their fermentability. Scientific and regulatory definitions of prebiotics differ greatly, although health benefits of these compounds are uniformly agreed upon to be due to their fermentability by gut microbiota. Scientific evidence suggests that 8 categories of compounds all exhibit health benefits related to their metabolism by colonic taxa.

Differential Accumulation and Degradation Of Anthocyanins In Red Norland Periderm is Dependent On Soil Type And Tuber Storage Duration

To determine how soil type, 2,4-dichlorophenoxyacetic acid (2,4-D) treatment, and storage affects color and anthocyanin accumulation of Red Norland potatoes, tubers were grown in sand or peat, with or without 2,4-D treatment, and measured at vine kill, harvest or after storage. Tubers grown in sand were less red and accumulated fewer anthocyanins than tubers grown in peat. 2,4-D treatment increased redness regardless of soil type. Redness loss varied greatly among tubers with storage. Tubers that lost color with storage had a two-fold reduction in anthocyanins, and a two-fold increase in benzoic and cinnamic acids compared to harvest, indicating chemical degradation of anthocyanidins via B-ring cleavage and autoxidation. Sand-grown potatoes did not exhibit greater cinnamic acids compared to peat-grown potatoes, suggesting that their color differences were due more to differences in biosynthesis than degradation during skin set. To improve Red Norland tuber color, research should focus on increasing biosynthesis of anthocyanins.ResumenPara determinar la influencia del tipo de suelo, el tratamiento con el ácido 2,4-diclorofenoxiacético (2,4-D) y el almacenamiento, sobre el color y acumulación de antocianinas en papa Red Norland, se sembraron tubérculos en arena o turba, con o sin tratamiento con 2,4-D, con mediciones al secado del follaje, a la cosecha, o después del almacenamiento. Los tubérculos que crecieron en la arena eran menos rojos y acumularon menos antocianinas que los cultivados en turba. El tratamiento con 2,4-D aumentó lo rojizo independientemente del tipo de suelo. La pérdida de la pigmentación roja varió grandemente entre los tubérculos con almacenamiento. Los tubérculos que perdieron el color en el almacén tuvieron el doble de reducción en antocianinas y un aumento al doble en ácidos benzoico y cinámico comparados a la cosecha, indicando degradación química de antocianidinas por vía del rompimiento del anillo B y por autooxidación. Las papas cultivadas en la arena no exhibieron mayores ácidos cinámicos en comparación con las cultivadas en la turba, lo que sugiere que sus diferencias en color se debieron más a diferencias en la biosíntesis que a la degradación durante el embarnecimiento de la piel. Para mejorar el color del tubérculo en Red Norland, la investigación debería enfocarse en el aumento de la biosíntesis de antocianinas.