FODMAP Content Like-by-like Comparison in Spanish Gluten-free and Gluten-containing Cereal-based Products.

Gluten-free foods (GF) availability on supermarket shelves is growing and it is expected to continue expanding in the years ahead. These foods have been linked to a lower content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), molecules that trigger gastrointestinal symptoms in sensitive persons. In this study, the FODMAP content of 25 cereal-based GF foods in Spain (breakfast cereals, pasta, bread, biscuits, bakery products, and dough and puff pastry) and 25 gluten-containing equivalents (GC) available in the same supermarket were analysed and compared. Lactose, fructose, glucose, sorbitol, mannitol, raffinose, stachyose and fructans were quantified. In a like-by-like analysis, GF foods were found to generally contain fewer FODMAPs than their GC counterparts. The ingredients used in the manufacture of GF cereal-based foods may contribute to this fact. When the individually wrapped size was considered, the proportion of samples classified as high-FODMAPs in GC and GF foods showed a trend towards fewer samples in the GF. However, not all the GF samples were low-FODMAP. Altogether, our findings provide essential information for FODMAP content databases of GF products in Spain.

Optimization and Validation of an HPAEC-PAD Method for the Quantification of FODMAPs in Cereals and Cereal-Based Products.

This study presents an analytical method for the quantification of fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) in cereals and cereal-based products, considering diverse ingredients, such as different cereals in addition to wheat, pulses, or pseudocereals. All carbohydrates have been separated, identified, and quantified with a high-performance anion-exchange chromatographic system coupled with a pulsed amperometric detection (HPAEC-PAD). The total fructan content and the average degree of polymerization (DPav) have been determined after enzymatic hydrolysis to the monomers glucose and fructose, on the basis of the principle of the official method for fructan quantification in food products, AOAC 997.08. The methods for extraction, separation, and detection as well as fructan determination are based on several other studies and were modified in order to minimize interferences in the analysis. The method has been validated with regard to the limits of detection and quantification, the linearity, the repeatability, and the accuracy as well as the DPav of the fructans.

Hydration shells of carbohydrate polymers studied by calorimetry and terahertz spectroscopy.

We present a study of the hydration shells of some carbohydrate polymers of commercial and biological importance, namely, agave fructans, inulin, and maltodextrin, employing terahertz time-domain spectroscopy and differential scanning calorimetry. We observe that the hydration numbers calculated using terahertz spectroscopy are marginally higher than those of the calorimetric values. We attribute this discrepancy to the definition of hydration number, which in a way correlates with the physical process used to quantify it. The aqueous solutions show a non-proportional increase in the absorption coefficient and the hydration number, with a decrease in the carbohydrate concentration. We demonstrate that this behavior is consistent with the "chaotropic" or "structure breaking" model of the hydration shell around the carbohydrates. In addition, the study reveals that agave fructans and inulin have good hydration ability. Given the high glass transition temperature and good hydration ability, these carbohydrates may behave as good bio-protectants and hydrating additives for food and beverages.

Fructan and free fructose content of common Australian vegetables and fruit.

Fructans are not digested in the small intestines of humans. While many health benefits have been attributed to these carbohydrates, they can cause gastrointestinal symptoms in some individuals. We measured the total fructans in 60 vegetables and 43 fruits using the Megazyme fructan assay. Vegetables with the highest quantity of fructans included garlic, artichoke, shallots, leek bulb, and onions (range, 1.2-17.4 g/100 g fw). Fruits with low, but detectable, fructans included longon, white peach, persimmon, and melon (range, 0.21-0.46 g/100 g fw). The fructan assay was modified to provide an estimate of the average chain length (degree of polymerization) for high fructan vegetables. d-Fructose can also be malabsorbed in the small intestine of humans, so the d-fructose content in some foods was measured to supplement the current food tables. Research in this area will be facilitated through the availability of more comprehensive food composition data.

Saccharomyces cerevisiae and Kluyveromyces marxianus Cocultures Allow Reduction of Fermentable Oligo-, Di-, and Monosaccharides and Polyols Levels in Whole Wheat Bread.

Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are small molecules that are poorly absorbed in the small intestine and rapidly fermented in the large intestine. There is evidence that a diet low in FODMAPs reduces abdominal symptoms in approximately 70% of the patients suffering from irritable bowel syndrome. Wheat contains relatively high fructan levels and is therefore a major source of FODMAPs in our diet. In this study, a yeast-based strategy was developed to reduce FODMAP levels in (whole wheat) bread. Fermentation of dough with an inulinase-secreting Kluyveromyces marxianus strain allowed to reduce fructan levels in the final product by more than 90%, while only 56%  reduction was achieved when a control Saccharomyces cerevisiae strain was used. To ensure sufficient CO2 production, cocultures of S. cerevisiae and K. marxianus were prepared. Bread prepared with a coculture of K. marxianus and S. cerevisiae had fructan levels ≤0.2% dm, and a loaf volume comparable with that of control bread. Therefore, this approach is suitable to effectively reduce FODMAP levels in bread.

Raisin dietary fiber composition and in vitro bile acid binding.

Raisins are dried grapes that are popular shelf-stable snacks. Three commercially important types of raisins were studied: sun-dried (natural), artificially dried (dipped), and sulfur dioxide-treated (golden) raisins. Dietary fiber composition was analyzed by AACC method 32-25. Polysaccharides were hydrolyzed, and the resulting sugars were analyzed by colorimetric and gas chomatographic methods. Fructans were measured with a colorimetric kit assay. Total dietary fiber values agreed with published values, with pectins and neutral polysaccharides of mannose and glucose residues predominating. Dipped raisins had over 8% fructans. No fructans were found in fresh grapes. Raisin types varied in their ability to bind bile acids in vitro. Coarsely chopped raisins bound more bile than did finely chopped or whole raisins.

Characterisation of dietary fibre components in cereals and legumes used in Serbian diet.

The typical Serbian diet is characterised by high intake of cereal products and also legumes are often used. The content of total fibre as well as certain fibre fractions was determined in cereals, cereal products, and cooked legumes. The content of total fibre in cooked cereals and cereal products ranged from 2.5 to 20.8 g/100 g, and in cooked legumes from 14.0 to 24.5 g/100 g (on dry matter basis). Distribution of analysed fibre fractions and their quantities differed significantly depending on food groups. Fructans and arabinoxylans were the most significant fibre fractions in rye flakes, and ß-glucan in oat flakes, cellulose and resistant starch were present in significant amounts in peas and kidney beans. When the size of regular food portions was taken into consideration, the best sources of total dietary fibre were peas and kidney beans (more than 11 g/serving). The same foods were the best sources of cellulose (4.98 and 3.56 g/serving) and resistant starch (3.90 and 2.83 g/serving). High intake of arabinoxylans and fructans could be accomplished with cooked wheat (3.20 g and 1.60 g/serving, respectively). Oat (1.39 g/serving) and barley flakes (1.30 g/serving) can be recommended as the best sources of ß-glucan.

A simple and accurate method for determining wheat grain fructan content and average degree of polymerization.

An improved method for the measurement of fructans in wheat grains is presented. A mild acid treatment is used for fructan hydrolysis, followed by analysis of the released glucose and fructose with high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Not only the amount of fructose set free from fructans but also the released glucose can be quantified accurately, allowing determination of the average degree of polymerization of fructans (DP(av)). Application of the mild acid treatment to different grain samples demonstrated that a correction should be made for the presence of sucrose and raffinose, but not for stachyose or higher raffinose oligosaccharides. The fructan content and DP(av) of spelt flour, wheat flour, and whole wheat flour were 0.6%, 1.2%, and 1.8% of the total weight and 4, 5, and 6, respectively. Validation experiments demonstrate that the proposed quantification method is accurate and repeatable and that also the DP(av) determination is precise.