Farage H. Al-Ghazzewi

Effects of konjac glucomannan hydrolysates on the gut microflora of mice

Purpose – The aim of this study is to determine the effects of depolymerised mannans and specifically konjac glucomannan hydrolysates (GMH) on the colonic microflora of mice. Blood glucose and cholesterol were also measured.Design/methodology/approach – Two groups (n = 20) of 12‐week old Wister mice were used for a period of 14 weeks. One group (treatment group) were fed diets containing 5 per cent konjac GMH dissolved in drinking water in addition to the control (group) standard diet. Faecal microflora, feed consumption, body weight, blood glucose and cholesterol were determined.Findings – The GMH promoted the growth of anaerobes and lactobacilli in the treatment group where this was statistically, highly significant (P < 0.001). Also, the hydrolysate was able to reduce highly significantly (P < 0.001) faecal Clostridium perfringens and Escherichia coli counts. A significant increase in average daily feed consumption (P < 0.05) and weekly body weight (P < 0.001) was found for the treatment group. The mea...

Efficacy of cellulase and mannanase hydrolysates of konjac glucomannan to promote the growth of lactic acid bacteria.

BACKGROUND Glucomannan polysaccharides may be hydrolysed to lower molecular weight molecules using acids or enzymes, specifically mannanases or cellulases. Mannanases (β-mannanases) hydrolyse β-(1-4)-linked mannose residues randomly in mannans whilst cellulases (β-glucanase) hydrolyse β-(1-4)-linked glucose residues. The molecular weight of the hydrolysate is clearly dependent on the amount of hydrolysis. One use of such hydrolysates has been towards their capacity to function as prebiotics. The relative efficacy of cellulase and/or mannanase hydrolysates of konjac glucomannan to promote the growth of lactic acid bacteria (LAB) has been evaluated. RESULTS The LAB growth profiles (expressed in colony forming units, as a function of time) in UHT milk containing konjac glucomannan hydrolysed with cellulase were significantly greater than those containing glucose (control) or konjac glucomannan mannanase hydrolysates. An equivalent mixture (1:1) of cellulase-mannanase hydrolysates added to the UHT milk also showed significant improvement on the LAB growth profiles (compared to the glucose or mannanase alone hydrolysates). Different LAB strains showed some variation in growth profiles on the hydrolysates although this was not significant as a function of carbon source. CONCLUSIONS Glucomannan hydrolysates produced with either mannanase or cellulase enzymes were effective growth promoters (carbon sources) of LAB. However, cellulase hydrolysates were most effective.

Beneficial health characteristics of native and hydrolysed konjac (Amorphophallus konjac) glucomannan

The impact of ingesting glucomannans on health is not limited to colonic-focused fermentation into short-chain fatty acids (SCFAs), which might have some local health benefits; it also helps in treating disease states and enhancing the bodys immune system, both within the gut and in/on other parts of the body. The local and systemic roles of hydrolysed glucomannans, especially konjac glucomannans, in the mouth, oesophagus, stomach, small intestine, large intestine, gut-associated lymphoid tissue (GALT), skin and vagina, are highlighted. Therapeutic applications are discussed.

Glucomannan hydrolysate (GMH) inhibition of Candida albicans growth in the presence of Lactobacillus and Lactococcus species

Konjac glucomannan hydrolysate (GMH) was compared with inulin and glucose for its capacity to support the growth of probiotic bacteria but inhibit the growth of Candida albicans in vitro. The growth of lactic acid bacteria (LAB) was studied under aerobic, anaerobic and 5% CO2 conditions where the GMH progressively supported the growth of LAB as a function of concentration (0.1, 0.5, 1.0 and 2.0% w/v). In mixed cultures, GMH promoted the growth of LAB (even at concentrations as low as 0.1%) and consequently increased inhibition of C. albicans under anaerobic conditions, 5% CO2 or aerobic conditions. Inhibition of C. albicans growth was generally higher than that with glucose or inulin and, of the LAB strains, Lactobacillus jensenii exhibited most inhibition of the pathogen. The stimulatory effects of low concentrations of GMH on LAB and inhibition of C. albicans make these prebiotic and probiotic combinations a potential prophylactic or therapeutic agent for vaginal episodes.

Effect of short term administration of konjac glucomannan hydrolysates on adult blood lipid parameters and glucose concentrations

Purpose – This paper aims to evaluate the effect of depolymerised glucomannan in regulating blood lipid and glucose concentrations. Design/methodology/approach – Twenty adult volunteers were recruited. Blood samples were taken at Day 0. The volunteers consumed drinks containing 3.0 g active glucomannan hydrolysates (AMH) for 14 days, after which time blood samples were retaken (Day 15). Blood samples were analysed to determine the blood lipid and glucose concentrations. Findings – The average fasting blood glucose at the start of the trial was 2.54 mmol/L but reduced slightly to 2.49 mmol/L after consumption of the glucomannan. The total average cholesterol at the start of the trial was higher (6.69 mmol/L) than desirable ( < 5.0 mmol/L). This was reduced after consuming the glucomannan to 6.44 mmol/L (3.74 per cent). The triglyceride content was also higher initially than recommended (2.88 mmol/L) but was reduced by 11.5 per cent. The high-density lipoprotein (HDL) was within the desirable range before a...

The synbiotic effects of konjac glucomannan hydrolysates (GMH) and lactobacilli on the growth of Staphylococcus aureus and Salmonella typhimurium

Purpose – The purpose of this paper is to investigate how synbiotic combinations of lactobacilli with konjac glucomannan hydrolysate (GMH) may be used to reduce Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium) growth in vitro.Design/methodology/approach – Growth of S. aureus and S. typhimurium was assessed individually and when mixed with L. acidophilus in modified media supplemented with two per cent GMH. The effect of the GMH and the Lactobacillus strain on S. aureus growth was also investigated using the well diffusion test on Muller‐Hinton agar medium.Findings – The results showed that L. acidophilus “out grew” the pathogens S. aureus and S. typhimurium in the presence of konjac glucomannan in the mixed cultures.Originality/value – The paper demonstrates that konjac glucomannan hydrolysates combined with probiotic bacteria, may be used to inhibit the growth of pathogenic bacteria such as S. aureus and S. typhimurium. These data support the development of an alternative app...

A preliminary study of the synbiotic effects of konjac glucomannan hydrolysates (GMH) and lactobacilli on the growth of the oral bacterium Streptococcus mutans

Purpose – The purpose of this paper is to determine the effect of synbiotic combination of lactobacilli with konjac glucomannan hydrolysate (GMH) to reduce Streptococcus mutans growth in vitro with the intention of characterising its efficacy as a new approach for oral hygiene.Design/methodology/approach – Strains of Lactobacillus acidophilus and S. mutans were grown individually or in combination in modified Columbia base broth supplemented with 2 per cent GMH. Following incubation, the samples were plated on De Man, Rogosa and Sharpe and Columbia blood agar and growth of both strains was assessed.Findings – The probiotic bacteria L. acidophilus was able to “out grow” S. mutans in the presence of konjac glucomannan in the mixed cultures.Originality/value – The results indicate that consumption of prebiotic and probiotic combinations may play a role as potential prophylactic or therapeutic agents for reducing the presence of organisms in the mouth associated with tooth decay. In order to confirm a benefic...

Intrinsic and extrinsic carbohydrates in the vagina: A short review on vaginal glycogen

The reasons for (i) the presence and (ii) mechanisms of utilisation of glycogen by the lactic acid bacteria in the human vaginal tract are not well understood. It is probable that the vaginal epithelia produce both glycogen and α-amylase where the enzyme depolymerises the polysaccharide within the vagina itself. Only these depolymerised residues are then utilised for growth by the lactic acid bacteria. The lactic acid bacteria cannot metabolise the glycogen directly due to their incapacity to produce the α-amylase enzyme. These bacteria may, however, metabolise exogenous carbohydrates (such as prebiotics) selectively for growth effectively. These carbohydrate utilisation issues within the vagina are considered in this short review.

Role of prebiotics and probiotics in oral health

Purpose This paper aims to focus on the utilisation of pre- and probiotics for oral care and the state of knowledge at this time. Design/methodology/approach Pre- and probiotics describe beneficial carbohydrates and microbiota, respectively, for optimal gut health. Carbohydrates provide energy selectively for the gut-friendly bacteria. The use of both carbohydrates and bacteria is, however, being expanded into other areas of the body – including the skin, vagina and oral cavity – for health-related applications. Findings There is increased interest in both pre- and probiotics for oral care products. The importance of oral microflora and their selective substrates is discussed against a background of contemporary oral care approaches. The issues and benefits are discussed in this review. Originality/value It is clear that consumption of prebiotics and probiotics may play a role as potential prophylactic or therapeutic agents for reducing the presence of organisms in the mouth associated with tooth decay. To confirm a beneficial effect of pre- and probiotics further in vivo studies involving healthy human volunteers should be considered.