The potential of resistant starch as a prebiotic

Resistant starch is defined as the total amount of starch and the products of starch degradation that resists digestion in the small intestine. Starches that were able to resist the digestion will arrive at the colon where they will be fermented by the gut microbiota, producing a variety of products which include short chain fatty acids that can provide a range of physiological benefits. There are several factors that could affect the resistant starch content of a carbohydrate which includes the starch granule morphology, the amylose–amylopectin ratio and its association with other food component. One of the current interests on resistant starch is their potential to be used as a prebiotic, which is a non-digestible food ingredient that benefits the host by stimulating the growth or activity of one or a limited number of beneficial bacteria in the colon. A resistant starch must fulfill three criterions to be classified as a prebiotic; resistance to the upper gastrointestinal environment, fermentation by the intestinal microbiota and selective stimulation of the growth and/or activity of the beneficial bacteria. The market of prebiotic is expected to reach USD 198 million in 2014 led by the export of oligosaccharides. Realizing this, novel carbohydrates such as resistant starch from various starch sources can contribute to the advancement of the prebiotic industry

Identification of Acacia Gum Fermenting Bacteria from Pooled Human Feces using Anaerobic Enrichment Culture

Commercial acacia gum (AG) used in this study is a premium-grade freeflowing powder. It is a gummy exudate composed of arabinogalactan branched polysaccharide, a biopolymer of arabinose and galactose. Also known as food additive, acacia gum (E414), which is presently marketed as a functional dietary fiber to improve overall human gut health. The health effects may be related to the luminal pH regulation from the short-chain fatty acids (SCFA) production. Studies suggested that amylolytic and butyrogenic pathways are the major factors determining the SCFA outcome of AG in the lower gut. However, the primary bacteria involved in the fermentation have not been studied. This study aimed to investigate the putative primary degraders of acacia gum in the gut ecosystem. Isolation and identification of gum-fermenting bacteria were performed through enrichment culture fermentation. The experiment was conducted in an anaerobic chamber for 144  h in three stages. The study was conducted in triplicate using an anaerobic chamber system. This culture system allows specific responses to support only bacteria that are responsible for gum fermentation among the gut microbiota. Five bacterial strains were isolated and found to be gum-fermenting bacteria. Based on the 16s RNA sequence, the isolates matched to butyrateproducing Escherichia fergusonii, ATCC 35469

Mineral content of five indigenous leafy vegetable from Bintulu market, Sarawak Malaysia

Indigenous leafy vegetables commonly consumed by local people in Bintulu, Sarawak, Malaysia. Most people consumed this group of vegetable without knowing the nutrient contents and its importance to the health. Five indigenous leafy vegetables, Scorodocarpus borneensis, Pangium edule, Gnetum gnemon, Dracaena gracilis, and Helminthostachys zeylanica were selected and analysed to determine their mineral contents. The vegetables were bought from Bintulu native market and mineral elements were analysed using standard method of AOAC. The result showed that S. borneensis and D. gracilis contains high concentration of P, .P. edule contains high Ca, Cu and Mg, H. zeylanica had highest Zn, Fe, K and Na and G. gnemon showed high Mn. The PCA result performed three distinct groups with respect to the nutrient elements. Group A: G. gnemon and H. zeylanica which contains K, Na, Fe, Mn and Zn. Group B: S. borneensis and D. gracilis with high P content and Group C: P. edulewith high Ca, Cu and Mg. The study of mineral contents of the indigenous leafy vegetables can help to improve the efficiency of nutrient intake by local people and further information is required to enable the vegetables to be introduced as new crops

Production of resistant starch type III from native sago starch as a potential prebiotic

Resistant starch (RS) is the sum of starch that escape upper gastrointestinal digestion and can be fermented by colonic microorganisms to produce beneficial metabolites such as short chain fatty acids (SCFA). Resistant starch can be a potential prebiotic, a non-digestible food ingredient that selectively stimulate the growth and/or activity of gut microorganisms, thus promoting the host health. The main focus of this study is to produce resistant starch type III from native sago starch. The resistant starch was produced via retrogradation process and with the aid of pullulanase enzyme. The quantification of total resistant starch content was determined based on the method approved by AOAC 2002.02 and AACC 38-40.01. From this study, it showed that there are no significant different between the resistant starch content of native and modified sago starches (RS type III)

Potential of novel dextran oligosaccharides as prebiotics for obesity management through in vitro experimentation

The energy-salvaging capacity of the gut microbiota from dietary ingredients has been proposed as a contributing factor for the development of obesity. This knowledge generated interest in the use of non-digestible dietary ingredients such as prebiotics to manipulate host energy homeostasis. In the present study, the in vitro response of obese human faecal microbiota to novel oligosaccharides was investigated. Dextrans of various molecular weights and degrees of branching were fermented with the faecal microbiota of healthy obese adults in pH-controlled batch cultures. Changes in bacterial populations were monitored using fluorescent in situ hybridisation and SCFA concentrations were analysed by HPLC. The rate of gas production and total volume of gas produced were also determined. In general, the novel dextrans and inulin increased the counts of bifidobacteria. Some of the dextrans were able to alter the composition of the obese human microbiota by increasing the counts of Bacteroides–Prevotella and decreasing those of Faecalibacterium prausnitzii and Ruminococcus bromii/R. flavefaciens. Considerable increases in SCFA concentrations were observed in response to all substrates. Gas production rates were similar during the fermentation of all dextrans, but significantly lower than those during the fermentation of inulin. Lower total gas production and shorter time to attain maximal gas production were observed during the fermentation of the linear 1 kDa dextran than during the fermentation of the other dextrans. The efficacy of bifidobacteria to ferment dextrans relied on the molecular weight and not on the degree of branching. In conclusion, there are no differences in the profiles between the obese and lean human faecal fermentations of dextrans

A review on the effects of prebiotics on cell toxicity and integrity

Prebiotics are known as the ‘food’ for beneficial gut microbiota that are capable of promoting host health. Their effects depend on the product of gut fermentation or metabolites. This paper discusses the role of prebiotics on cytotoxicity, genotoxicity, and cell integrity. Metabolites produced from the fermentation of prebiotics can be used to understand gut diseases such as colorectal cancer. Fecal water from in vivo or in vitro studies can be used to understand the relationship between prebiotics and gut diseases because of its close contact with colon epithelium. Besides, fecal water has compounds that are capable of modifying colonocytes

Resistant starch evaluation and in vitro fermentation of lemantak (native sago starch), for prebiotic assessment

Resistant starch is the non-digestible portion of starch that reaches the colon and act as a prebiotic to stimulate the activity and growth of beneficial gut microbiota. In the present study, resistant starch content of native (lemantak), commercialized and retrograded sago and starch was analysed, and the in vitro fermentability with known probiotics were investigated. Retrograded starch was produced through two cycles of autoclaving and cooling steps. The resistant starch content of each modified starch were measured based on the method approved by AOAC 2002.02. The in vitro batch fermentation was carried out with inoculation of Lactobacillus acidophilus and Bifidobacterium animalis at 37°C for 24 hours in anaerobic condition. Total bacteria was enumerated at 0, 6, 12 and 24 hours. Highest resistant starch content was shown in lemantak (native sago starch) at 62.61%. Lemantak was also shown to be the most preferred fermentation substrate with the highest number of total bacterial count at all sampling hours. These findings suggest the potential of lemantak as a prebiotic

Diversity, utilization and proximate composition of indigenous leafy vegetables consumed in Malaysia

The availability of indigenous leafy vegetables abundantly available in rural communities’ surroundings plays important role in its sustainability. A study was conducted at three native markets in Bintulu Division of Malaysia: Bintulu (N 3º10’29.5″ E 113º02’27.8″)Tatau (N 2º52’34.4″ E 112º51’09.6″) and Sebauh(N 3º06’38.6″ E 112º16’05.7″) to determine the plant species frequently used as leafy vegetables by the locals. The structured questionnaire was distributed to identify the species consumed and gather the information on species used for food consumption, vernacular name and utilization methods. Twenty species from 18 different families were identified with Euphorbiaceae dominated by three species. The locals used the indigenous leafy vegetables (ILV) in the preparation of fried vegetables, eaten raw, fermented and seasoning. The proximate composition conducted on 13 species of ILV revealed that these vegetables contains significantly high moisture (63.83 – 88.08%), fiber (9.20 – 27.39%) and carbohydrate (33.33 – 61.32%) contents whereas the fat (0.09 – 1.09%), proteins (0.25 – 1.65%) and energy (128.89 – 277.53 Kcal/100g) are low. The consumption of the ILV are recommended due to its potential to supply adequate intake of essential nutrients. Further study on the nutritional values of the ILV should be conducted to reveal many information on its nutritional values

The prebiotic effect of α-1,2 branched, low molecular weight dextran in the batch and continuous faecal fermentation system

The aim of this study was to establish the effect of smaller molecular weight (0.5 and 1.0 kDa) on prebiotic efficacy and its putative sustainability in the human gut. The prebiotic effect of α-1,2 branched, 0.5 and 1 kDa dextrans were evaluated in faecal batch fermentations as compared with inulin. Both dextrans induce similar selectivity towards Bifidobacterium sp., Lactobacillus/Enterococcus and Bacteroides/Prevotella, and producing similar concentrations of short chain fatty acids. However, the 0.5 kDa dextran was fermented faster than the 1 kDa dextran, where both produced lower amount of gas than inulin. The fermentation of 1 kDa dextran was further investigated in continuous gut models. The dextran increased Bifidobacterium and Roseburia sp. populations in the final vessel, while decreasing Clostridium histolyticum and Faecalibacterium prausnitzii. Overall, the α-1,2 branched, 1 kDa dextran induced selective effect on the gut microbiota and stimulated short chain fatty acids, indicating prebiotic sustainability in distal regions of the gut

Physicochemical properties of microwave heated sago (Metroxylon sagu) starch

Sago starch is an underutilized starch due to its low functionality in food formulation. Modification is effective in improving starch functional properties. In this study, the starch were modified to enhance its functional properties. The starch was microwave-heated with different treatment durations of 5, 10, 15, or 20 min, separately, yielding microwave-heated starches (MHT1, MHT2,MHT3, and MHT4). The modified starches have irregular shaped granules and fissures while maintaining their mean diameters. The degree of double helix had increased, indicating more double helix structure of amylose formed. The modified starches’ moisture content, solubility, and paste clarity were significantly decreased. The MHT4 had its swelling power and syneresis increase. In conclusion, the treatment duration influenced the physicochemical properties of the sago starch, which is related to the formation of amylose double helix structure. Further study should focus on the formation of double helix structure in starch and its impact towards food structure