Biochemical perspectives of xylitol extracted from indigenous agricultural by-product mung bean (Vigna radiata) hulls in a rat model.

BACKGROUND: The production of xylitol from lignocellulosic material is of great interest around the world. It can be used as bulk sweetener and its possible lower energy value has increased acceptance for discerning consumers. Xylitol was produced from indigenous agricultural by-product (mung bean hulls) through Candida tropicalis fermentation. Further, xylitol incorporation at different concentrations (0, 100 and 200 g kg⁻¹) was carried out with the purpose of appraising the suitability and claimed health benefits of this dietetic ingredient in food products. Asserted biochemical perspectives of the xylitol intake were evaluated through biological studies for normal and streptozotocin-induced diabetic rats. RESULTS: The addition of xylitol significantly affected feed intake, weight gain, liver and cecum weight in both normal and diabetic rats. The biochemical profile of serum was improved with xylitol incorporation in the diet. Serum glucose, cholesterol and triglycerides levels were decreased depending on xylitol intake level. CONCLUSION: The results of the present study demonstrated that mung bean hulls have high potential as a new feedstock for xylitol production. In addressing the current concerns of obesity and diabetes, xylitol extracted from such agricultural waste should be considered in diet-based therapies for weight loss programmes.

Xylitol as a prophylaxis for acute otitis media: systematic review.

A systematic review was conducted to evaluate evidence regarding xylitol, a sugar alcohol, as a prophylaxis for acute otitis media (AOM) in children. The authors searched PubMed and other databases to identify evidence. Criteria for included studies were: appear in English-language, peer-reviewed journals; at least quasi-experimental designs; use xylitol; and present outcome data. The authors completed evaluation forms for the included studies at all phases of the review. The authors reviewed 1479 titles and excluded 1435. Abstracts and full texts were reviewed for the remaining 44; four randomized controlled trials met inclusion criteria. Xylitol was a generally well accepted prophylaxis for AOM with few side effects when administered via chewing gum or syrup at 10 g/day given five times daily. Meta-analysis revealed significant treatment effects (Risk ratio = 0.68; 95% confidence interval = 0.57 to 0.83). Xylitol can be a prophylaxis for AOM, but warrants further study, especially of vehicles other than chewing gum for young children, and information is needed regarding cost, duration of administration required, and expected long-term effects.

Improving downstream processes to recover tartaric acid, tartrate and nutrients from vinasses and formulation of inexpensive fermentative broths for xylitol production.

BACKGROUND: Vinasses, the main liquid wastes from the distillation process of grape marc and wine lees, are acidic effluents with high organic content, including acids, carbohydrates, phenols, and unsaturated compounds with high chemical oxygen demand, biological oxygen demand and solid concentrations. These wastes can be revalued to provide additional benefits when they are employed as feedstock of some compounds including tartaric acid, calcium tartrate and economic nutrients for the elaboration of fermentable broths. RESULT: This study attempts to recover tartaric acid and calcium tartrate from vinasses. All the tartaric acid initially solubilised was recovered in both processes. The residual streams can be successfully employed as economic nutrients for the xylose to xylitol bioconversion, achieving higher global volumetric productivities (Q(P, xylitol) = 0.232 g L(-1) h(-1)) and products yields (Y(xylitol/S) = 0.57 g g(-1)) than fermentations carried out using commercial nutrients (Q(P, xylitol) = 0.193 g L(-1) h(-1) and Y(xylitol/S) = 0.55 g g(-1) respectively). CONCLUSION: Tartaric acid can be recovered from vinasses in the form of tartaric acid crystals and calcium tartrate. The residual streams generated in the process can be used as economic nutrients for the production of xylitol by D. hansenii.

Sealants and xylitol chewing gum are equal in caries prevention.

Sealants and xylitol have been demonstrated to prevent dental decay, but their effect has never been compared in the same study. Regular use of xylitol chewing gum during 2 or 3 school years was compared with application of occlusal sealants in a randomized study. The reliability of the clinical observations was controlled by examining the presence of dental decay in the same teeth from bitewing radiographs in a blind study. After 5 years, no statistically significant differences between the sealant and xylitol groups were found. The results were in line with the results from separate studies with sealants or xylitol. There were no great differences between the costs of the measures. The selection between the compared preventive measures has to be made on the basis of practical aspects such as caries occurrence, availability of personnel and other resources, opportunity costs, cooperation with schools, and other local conditions.

Improvement of xylitol production by Candida guilliermondii FTI 20037 previously adapted to rice straw hemicellulosic hydrolysate.

AIMS: To evaluate a simple and economical technique to improve xylitol production using concentrated xylose solutions prepared from rice straw hemicellulosic hydrolysate. METHODS AND RESULTS: Experiments were carried out with rice straw hemicellulosic hydrolysate containing 90 g l-1 xylose, with and without the addition of nutrients, using the yeast Candida guilliermondii previously grown on the hydrolysate (adapted cells) or on semi-defined medium (unadapted cells). By this method, the yield of xylitol increased from 17 g l-1 to 50 g l-1, and xylose consumption increased from 52% to 83%, after 120 h of fermentation. The xylitol production rates were very close to that (0.42 g l-1 h-1) attained in a medium simulating hydrolysate sugars. CONCLUSION: Yeast strain adaptation to the hydrolysate showed to be a suitable method to alleviate the inhibitory effects of the toxic compounds. Adapted cells of Candida guilliermondii can efficiently produce xylitol from hydrolysate with high xylose concentrations. SIGNIFICANCE AND IMPACT OF THE STUDY: Yeast adaptation helps the bioconversion process in hydrolysate made from lignocellulosic materials. This low-cost technique provides an alternative to the detoxification methods used for removal of inhibitory compounds. In addition, the use of adapted inocula makes it possible to schedule a series of batch cultures so that the whole plant can be operated almost continuously with a concomitant reduction in the overall operation time.

Timing of first restorations before, during, and after a preventive xylitol trial.

An independent longitudinal retrospective analysis of the timing, number, and cost of tooth restorations was conducted for all subjects (n = 313) in the age cohort of a municipal health center, in which two consecutive field trials of up to 3 years on the caries-preventive effect of the use of xylitol chewing gum were conducted (Ylivieska study, 1982-85). A computer program calculated the post-eruptive timing of the first restorations on each permanent tooth surface, and survival analysis methods were applied before, during, and after the trials. The cost of restorations was then calculated. The total number of new restored surfaces was 4.0 per child in the xylitol group and 9.3 in the controls during the decade after onset of the trial. The number of restorations on the occlusal surfaces of the first molars leveled off at 40-50% in the xylitol group and at about 60-70% in the control group. Plateaus for the second molars were at 30-40% and 60-70%, respectively. The time lag for the first restorations was longer in the xylitol group for the proximal and other smooth surfaces. A marked difference in favor of the xylitol group was observed in the proximal surfaces of the upper incisors (for example, the mesial surface of the upper mesial incisor for girls: log-rank chi-square = 11.1, p < 0.001). The preventive effect was most pronounced in teeth that had erupted during the trial. This analysis indicated that participation of subjects in the xylitol chewing gum trials resulted in a significant reduction in the number of first restorations and hence in costs during the decade after the onset of gum use.