Composición de la fibra alimentaria en el orujo de aceituna. Aminoácidos asociados a la fibra insoluble, soluble y total

Soluble sugars and dietary fibre were determined and the main components of the insoluble, soluble and total dietary fibre were analyzed. Aminoacids in both olive cake and fibre fractions were also studied. The results showed that olive cake fractions were also studied. The results showed that olive cake consists mainly of an alcohol insoluble residue that accounts for 77% of the dry matter (Klason lignin 37%, non-cellulosic polysaccharides 24%, cellulose 19% and protein 10%). Free sugars constitute 10% of the dry matter. Nearly 80% of all the amino acids in olive cake is associated with the insoluble dietary fibre fraction of these hydroxyproline and lysine are completely undigestible and methionine is the most available.Se determinó el contenido en azúcares solubles y fibra alimentaria del orujo de aceituna, analizándose los principales componentes de las fracciones de fibra insoluble, soluble y total. Asimismo, se realizó un análisis detallado de los aminoácidos no asociados a la fibra y de los presentes en cada fracción de la misma. Los resultados muestran que dicho subproducto está constituido fundamentalmente por un residuo insoluble en alcohol (77%) que contiene principalmente lignina Klason (37%), polisacáridos no celulósicos (24%), celulosa (19%), y proteína (9%). Los azúcares libres constituyen el 10% en peso, de los cuales el 60% es sacarosa. Aproximadamente el 80% del total de aminoácidos del orujo están asociados a la fibra insoluble, encontrándose que algunos de ellos, como hidroxiprolina y Usina, estaban no disponibles en su totalidad, mientras que metionina era el más ampliamente solubilizado

In vitro fermentability of differently digested resistant starch preparations

The in vitro fermentability of two resistant starch preparations type 2 (RS2) and type 3 (RS3) was investigated using human colonic microbiota. Prior to the fermentation experiments, samples were digested using two in vitro models, a batch (ba) and a dynamic (dy), as well as an in vivo method (il) for RS3. Digestion residues were fermented in vitro using a simple batch model lasting 24 h and a more sophisticated dynamic model enduring 72 h. During batch fermentation, metabolite productions and starch degradation rates were similar for RS2 and RS3 but higher for dy- compared to ba-digested samples. RS3il led to the lowest fermentability. Furthermore, increased butyrate ratios were observed for all preparations. The varying RS preparations behaved similarly in the dynamic fermentation but showed high SDs. Moreover, the fermentability was slow during the first 24 h, indicating that the microbiota needed an adaptation period to ferment RS. Propionate ratios increased at the expense of butyrate with exception for RS2dy showing an increase in acetate only. Differences in fermentability observed between the dynamic model, allowing a closer simulation of the in vivo behavior, and the batch model, recommended for screening purposes, could be due to the varying microbiota used. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA

Fermentation of resistant starches: influence of in vitro models on colon carcinogenesis

Resistant starch type 2 (RS2) and type 3 (RS3) containing preparations were digested using a batch (a) and a dynamic in vitro model (b). Furthermore, in vivo obtained indigestible fractions from ileostomy patients were used (c). Subsequently these samples were fermented with human feces with a batch and a dynamic in vitro method. The fermentation supernatants were used to treat CAC02 cells. Cytotoxicity, anti-genotoxicity against hydrogen peroxide (comet assay) and the effect on barrier function measured by trans-epithelial electrical resistance were determine. Dynamically fermented samples led to high cytotoxic activity, probably due to additional compounds added during in vitro fermentation. As a consequence only batch fermented samples were investigated further. Batch fermentation of RS resulted in an anti-genotoxic activity ranging from 9-30% decrease in DNA damage for all the samples, except for RS2-b. It is assumed that the changes in RS2 structures due to dynamic digestion resulted in a different fermentation profile not leading to any anti-genotoxic effect. Additionally, in vitro batch fermentation of RS caused an improvement in integrity across the intestinal barrier by approximately 22% for all the samples. We have demonstrated that batch in vitro fermentation of RS2 and RS3 preparations differently pre-digested are capable of inhibiting the initiation and promotion stage in colon carcinogenesis in vitro

Physiological and metabolic properties of a digestion-resistant maltodextrin, classified as type 3 retrograded resistant starch

There is a growing interest in highly fermentable dietary fibers having the potential to reduce risks of disease through the production of short-chain fatty acids (SCFA). Recently a digestion-resistant retrograded maltodextrin (RRM), classified as type 3 resistant starch was developed. Systematic work to determine its molecular and physiological properties was carried out to determine (1) the fraction resistant to digestion in vitro and in vivo, (2) its postconsumption effect on blood glucose in healthy volunteers, and (3) its in vitro fermentation pattern, at different ages, by use of pooled fresh human fecal inoculum. RESULTS: The digestion resistant fraction obtained in vivo from ileostomy patients (59.4%) is similar to that obtained by the AOAC method for measuring retrograded resistant starch (59.7%). The relative glycemic response after consumption of 50 g of RRM was 58.5% compared to glucose set as 100%. When exposed to colonic microbiota, in vitro obtained indigestible fractions behave similarly to those obtained in vivo in ileostomy patients. Fermentation of RRM and production of butyric acid is negligible during the first months of life but develops subsequently during weaning. In adults, RRM fermentation results in a high yield of SCFA, with butyrate representing 21-31 mol % of total SCFA. The high yield of SCFA during colonic fermentation, observed from weaning age on, as well as the potential to help reduce glycemic load may be of benefit to a number of health-related functions in the host. Further study on clear clinical end points is warrante