Fructan Content Research Articles

Breads fortified with wholegrain cereals and seeds as source of antioxidant dietary fibre and other bioactive compounds

Antioxidant dietary fibre (DF) and bioactive compounds are considered important factors for nutritional and health-promoting properties of cereal products. Breads fortified with wholegrain cereals and seeds are increasingly demanded, making it necessary to investigate the influence of these ingredients on nutritional value of breads. The aim of this study was to assess the impact of wheat flour fortification on the composition in antioxidant DF, non-glycemic oligosaccharides, polyphenols (PC), and antioxidant activity (AA) of the final bread products. Breadmaking affected bioactive compounds in different way depending on flour composition. Although wholegrain flour was the most sensitive to breadmaking process, both multigrain and wholegrain breads stood out for their level in DF, PC and AA, whereas white bread showed higher fructan content. Results showed that replacing of refined flour with other cereals (rye, oat), fibre (wheat bran, wheat fibre) and seeds (flaxseeds, sunflower, sesame) would improve the potential health benefits of breads.

Quality aspects in open-pollinated onion varieties from Western Europe

Commercial onion breeders limit their selection criteria by focusing almost exclusively on conventional farming. This raises the demand for certain well known varieties, but lowers the general diversity available on the mainstream market. A way to maintain biodiversity is to preserve old open-pollinated varieties. Through their distinct aroma and flavor, these plants are again drawing the interest of farmers and consumers alike, making them a viable alternative to commercial varieties. To assess yield and quality aspects of West-European open-pollinated onions, we have evaluated nine varieties and compared them against two of their commercial, well-established counterparts. The study included onion production on the field in South-West Germany, evaluation of the quality and flavor parameters, as well as a trained sensory taste panel. Results showed high diversity in yield and chemical properties of the studied onion varieties, where two varieties in particular, stood out significantly. Compared to the control, the variety “Birnformige” performed best and demonstrated high concentrations of fructan and pyruvic acid, both known to have curative and medicinal properties. On the other end of the spectrum, the variety “Jaune des Cevennes” demonstrated low dry matter content, low concentration of enzymatically-produced pyruvic acid and a high bolting percentage. The study also confirmed the link between individual quality components in onion bulbs, including the significantly negative correlation between minerals (such as calcium and magnesium) and fructan.

Effect of maltodextrin reduction and native agave fructans addition on the physicochemical properties of spray-dried mango and pineapple juices.

The effects of the partial replacement of maltodextrin by native agave fructans on the characteristics of spray-dried pineapple and mango powder were evaluated in this study. An experimental 33 design, three concentrations of maltodextrin (5, 7, and 10%), three concentrations of native agave fructans (0, 2, and 4%), and three feed temperatures (110, 115, and 120 ℃) were used. The results using the treatment in which only maltodextrin was used as a reference indicated that an increment in the inlet temperature decreases the moisture content, aw, and solubility. Likewise, an increase (more than 2%) in fructans concentration generates products with increased aw, moisture, hygroscopicity, wettability, and greater solubility. Additionally, no modification of storage stability was observed. Mango and pineapple powder color were affected mainly by the inlet temperature, causing an increase in luminosity (L*) and a decrease in parameter ( a*). A scanning electron microscopy showed spherical powder particles with certain contractions; powder stability in treatments with native agave fructans was not modified in the treatment at 2%. Finally, the addition of 2% agave fructans as carrier material was able to reduce the maltodextrin concentration of the spray drying process.

The influence of agave fructans on thermal properties of low-fat, and low-fat and sugar ice cream

The thermal properties of low fat, and low fat and sugar ice cream formulations, in which agave fructans were used as a sugar and fat, were evaluated by Modulated Differential Scanning Calorimetry. Approximately 3.0 g/100 mL of agave fructans promoted a positive effect on thermal properties for both types of formulation, showing a significantly lower (P < 0.05) fraction of frozen water. The highest concentration of agave fructans resulted in the highest percentage of non-frozen water (P < 0.05). The addition of agave fructans led to a significantly higher (P < 0.05) glass transition temperature. Glass transition incited a change in heat capacity as moisture and agave fructans increased. Agave fructans had the ability to reduce the number and formation of ice crystals, and hence the melting temperature of ice cream. The samples with longer melting time resulted in a reduction of energy, showing low enthalpy values. The quantity of agave fructans used as fat and sugar replacer affected the infrared spectroscopy spectra, and led to an increase in the magnitude of the bands, especially in the O-H group that corresponds to polymeric hydrogen bonding between agave fructans and water.

Effect of soil salinity on fructan content and polymerization degree in the sprouting tubers of Jerusalem artichoke (Helianthus tuberosus L.)

In addition to their role as reserve carbohydrates, fructans have been recognized as compounds that are protective against adverse environments. The aim of this study was to identify changes in the content and the degree of polymerization (DP) of fructan in sprouting tubers of Jerusalem artichoke under salt stress. Fructan was extracted from tubers at 1, 3, 5, and 7 days after planting in sandy loam soil irrigated with NaCl solution. Fructan accumulation and polymerization and the expression of genes encoding enzymes for fructan synthesis and degradation were evaluated. No significant differences between the control and treatment groups were observed until 5 days after sowing. The highest level of salinity (250 mM) not only inhibited sprouting and root growth but also decreased the level of fructan in the tubers. The proportion of fructan at DP 2–5 rapidly increased one day after sowing and then decreased over time. Under various NaCl treatments, at 7 days after sowing, all fructans except fructan at DP 6–10 were present in proportions less than or equal to the control. The variation in the DP of fructan was related to the transcription level of fructan metabolism genes. Fructan may support sprouting or resistance to salt stress by changing the DP of fructan molecules through hydrolysis without changing the total amount of fructan. The low-molecular-weight oligosaccharides (DP < 5) may be the major carbohydrates that support tuber sprouting or that are involved in protection from salt stress.

Molecular breeding of transgenic perennial ryegrass (Lolium perenne L.) with altered fructan biosynthesis through the expression of fructosyltransferases

Perennial ryegrass is the most important forage grass used in temperate agriculture. Transgenic perennial ryegrass events with altered fructan biosynthesis have the potential not only to increase animal production by improving digestibility of the grasses, but also to increase pasture intake by the animal due to lower neutral detergent fibre (NDF) concentrations. Transgenic perennial ryegrass plants were shown to have increased (P < 0.05) in fructan concentrations of leaf blades in transgenic T0 events and have thus an increase in water-soluble carbohydrate and in vivo dry matter digestibility concentrations as well as a decrease in the NDF concentration within the plant in spring and summer. These changes in nutritive value have led to an increase in metabolisable energy of up to 1.7 MJ ME·kg DM−1 in selected T0 events compared to FLp418-20 during spring and summer, with no differences in autumn or winter. The field evaluation of these events and the further development of these events using molecular breeding technologies are described in this paper.

Wheat preharvest herbicide application, whole‐grain flour properties, yeast activity and the degradation of glyphosate in bread

SummaryThe aim of this study was to determine the effects of wheat preharvest application of a glyphosate‐based herbicide (Roundup WeatherMax® with Transorb® 2 Technology) on whole‐grain flour composition and properties, including yeast activity. The effect of dough fermentation on the degradation of herbicide residues was also estimated. Grain samples from two hard red spring wheat varieties exceeded the maximum residue limits (5 mg kg−1) in Canada. Glyphosate had minor effects on wheat kernels composition and properties, including fructans content and yeast gassing power. No degradation of Roundup® or pure glyphosate was seen after dough fermentation for up to 4 h and baking. These results call for more scientific studies on glyphosate residues in wheat.

Optimization of the enzyme-assisted extraction of fructans from the wild sotol plant ( Dasylirion wheeleri )

Abstract Enzymatic liquefaction conditions were evaluated to obtain fructan from wild sotol plant (Dasylirion wheeleri) using the commercial preparation Pectinex Ultra SP-L. Ground sotol head was subjected to enzymatic extraction at various enzyme activities (0.0–175.73 U/mL) and fresh sotol concentrations (4.47–28.52 g/100 mL) at 30 °C for 8 h, using the response surface methodology to optimize the fructan extraction. Reducing sugars (RS), total carbohydrates (TC), fructan content (FRU), fructan profile, and the average degree of polymerization (DPn) were evaluated. Additionally, RS release kinetics and the enzyme rate constant (V0) were calculated. Enzyme concentration and substrate significantly affected (P 87.87 U/mL enzyme, and fructan extraction was maximal (39.08 g/100 g d.m.) at 83.04 U/mL enzyme and 6.70 g/100 mL substrate. V0 and RS content exhibited similar trends. DPn increased as substrate concentration decreased. Optimal enzymatic liquefaction conditions were 11.6–45.6 U/mL enzyme and 9.15–12.6 g/100 mL sotol, yielding elevated fructan (38.58 g/100 g d.m.), DPn of 8–10, and low fructose (1.8 g/100 g d.m.) and glucose (2.2 g/100 g d.m.) contents. These results demonstrate the feasibility of enzymatic liquefaction for extracting fructans from sotol heads without modifying the molecular structure.

Effects of Sampling Time, Cultivar, and Methodology on Water- and Ethanol-Soluble Carbohydrate Profiles of Three Cool-Season Grasses in Central Kentucky

Cool-season grasses (CSGs) accumulate variable amounts of water-soluble carbohydrates (WSCs, monosaccharides and disaccharides, and fructans), depending on climate, time of day and year, and genotype. Fructan concentrations in CSG are sometimes estimated as the difference between concentrations of WSC and ethanol-soluble carbohydrates (ESCs, monosaccharides and disaccharides, and variable amounts of fructan). Characterizing both WSC and ESC may improve understanding of soluble carbohydrate profiles in pastures and inform grazing management decisions, particularly for horses at risk for laminitis. Three CSG cultivars from Kentucky pastures were collected in the morning and afternoon on two springtime dates. Water-soluble carbohydrates and ESC were extracted with water or 80% ethanol, respectively, and analyzed by high-performance liquid chromatography (HPLC) and a colorimetric assay. Method of analysis (HPLC or colorimetry), and extraction solvent, affected the composition of WSC or ESC determined in CSG samples, demonstrating the need to consider methodology when interpreting results. Total soluble carbohydrate (mean of WSC and ESC) concentrations across cultivars and harvests were generally higher in the afternoon than in the morning, based on both HPLC (P = .0023) and colorimetric (P < .0001) analysis. The diurnal variation was mainly due to sucrose (P < .0001). Among cultivars, monosaccharides and disaccharides constituted the majority of the averaged WSC and ESC concentrations. The proportions of water- and ethanol-soluble fructan (P = .0101), and fructan chain lengths detected in water and ethanol extracts (P < .0001), differed among CSG cultivars. In choosing CSG cultivars for pastures, both soluble carbohydrate composition and concentrations should be considered.

Effects of baking on dietary fibre, with emphasis on β-glucan and resistant starch, in barley breads

In this study, 50% sifted barley flour from six different varieties and 50% refined wheat flour was used to bake bread. The flour mixture and the bread crumb and crust were analysed for content and composition of total dietary fibre, arabinoxylan, fructan, β-glucan, starch and resistant starch. Total dietary fibre content and extractability were not changed significantly by bread making. The extractability of mixed-linkage (1 → 3), (1 → 4)- β-D-glucan (β-glucan) increased with baking, while the average molecular weight of β-glucan decreased. However in one variety, SLU 7, higher average molecular weight was maintained and a different pattern was apparent in the molecular weight distribution. SLU 7 is thereby promising for inclusion in bread where a higher molecular weight of β-glucan is preferred, especially since the content of β-glucan in SLU 7 is high. The resistant starch formed positively correlated with amylose content. The high amylose variety yielded 2.9% resistant starch in the bread crumb, making an important contribution to total dietary fibre.

Carbohydrates Components of Some Italian Local Landraces: Garlic (Allium sativum L.)

Garlic is one of the most widespread and ancient medicinal plants. Its health benefits are due to its chemical components, and among these is carbohydrate, whose characteristics have been so far little investigated. The aim of this study is to typify the various components of carbohydrate (starch, individual sugars, fructans, and total dietary fibre) in four commonly consumed “Italian local landraces”: Bianco Piacentino, Rosso di Castelliri, Rosso di Sulmona, Rosso di Proceno, which are grown in two different geographical areas—Viterbo and Alvito—under the same agronomic conditions. This study will also evaluate how genotype and the cultivation area can affect the profile of the carbohydrate components of these landrace strains. Regarding unavailable carbohydrates, all of the varieties showed appreciable contents of fructans, the most representative component, which ranged from 45.8 to 54.4 g/100 g d.w. In contrast, total dietary fibre values varied from 9.1 to 13.1 g/100 g d.w. in Rosso di Castelliri and Bianco Piacentino, respectively, which are both grown in Viterbo. As for starch, only some traces were found, while the amount of total sugars ranged between 2.12 and 3.27 g/100 g d.w., with higher levels of sucrose. Our findings could provide important information that may be adopted to enhance and promote the quality of some local Italian garlic landraces through highlighting the influence that the cultivar and the environmental conditions can have on carbohydrates components.

Relationship of Macronutrients and Nonstructural Carbohydrate Concentration in Clippings of Creeping Bentgrass Putting Greens in Japan

Creeping bentgrass (Agrostis stolonifera L.) is the predominant cool‐season turfgrass of putting greens in Japan. Most areas of Japan are in the transition zone, and its hot and humid summer translates to many turf management challenges. Nonstructural carbohydrates are used by plants to sustain growth during periods of stress when photosynthesis is compromised and have been widely used as a physiological measure of stress tolerance. In our previous study, we demonstrated that the fructan concentration of leaf clippings can be used as an index for total nonstructural carbohydrates in creeping bentgrass. In this study, we examined the relationships between fructan concentration and macronutrient (N, P, or K) concentration in clippings from creeping bentgrass putting greens across &gt;200 golf courses in Japan over an 8‐yr period. The leaf fructan concentration tended to be high in December to February and low in August to September, before some increase in October. The leaf N concentration was less affected by season than fructan concentration, with a small increase seen from June to October and a small decrease in December. The leaf P concentration tended to be high in July and August and low in January and February. The leaf K concentration showed smaller seasonal change. The leaf N concentration was negatively correlated with fructan concentration in each month. The relationship between P and fructan concentration varied with season. The relationship between K and fructan was similar to that of P and fructan, but the correlation was much weaker.

Effect of Rhizome Fragmentation, Clover Competition, Shoot-Cutting Frequency, and Cutting Height on Quackgrass (Elymus repens)

Quackgrass is a problematic agricultural weed in the temperate zones of the world and is difficult to control without herbicides or intensive tillage. However, it may be possible to control quackgrass with less environmental impact by combining multiple low-intensity control methods. A pot experiment was conducted in July to October 2012 and repeated in June to September 2013 to investigate the effect of rhizome fragmentation, competition from white clover, shoot-cutting frequency, and cutting height on quackgrass. Rhizome fragmentation was expected to result in more, but weaker, quackgrass shoots that would be more vulnerable to shoot cutting and competition. However, by 20 d past planting, rhizome fragmentation did not change the total number of quackgrass shoots per pot, because an increase in main shoots was offset by a decrease in tiller numbers. Rhizome fragmentation did not reduce quackgrass biomass acquisition during the experimental period. Although rhizome fragmentation did reduce total fructan content, it did not enhance the effect of clover competition, shoot-cutting frequency, or shoot-cutting height. Clover competition by itself reduced quackgrass shoot numbers by 72%, rhizome biomass by 81%, and belowground fructan concentration by 10 percentage points, compared with no competition. The more frequently quackgrass shoots were cut, the less biomass quackgrass acquired, and a high shoot-cutting frequency (each time quackgrass reached 2 leaves) resulted in a lower belowground fructan concentration than a low shoot-cutting frequency (at 8 leaves). However, in pots without competition, a higher shoot-cutting frequency resulted in more quackgrass shoots. A lower shoot-cutting height (25 mm) had more impact when shoot cutting was more frequent. In conclusion, rhizome fragmentation did not reduce the number of quackgrass shoots or rhizome biomass, but competition from white clover, a high shoot-cutting frequency, and a low shoot-cutting height strongly suppressed quackgrass biomass and fructan acquisition.

Effects of levan-type fructan on growth performance, nutrient digestibility, diarrhoea scores, faecal shedding of total lactic acid bacteria and coliform bacteria, and faecal gas emission in weaning pigs.

The use of antibiotics as growth promoters in feed has been fully or partially banned in several countries. The objective of this study was to evaluate effects of levan-type fructan on growth performance, nutrient digestibility, faecal shedding of lactic acid bacteria and coliform bacteria, diarrhoea scores, and faecal gas emission in weaning pigs. A total of 144 weaning pigs [(Yorkshire × Landrace) × Duroc] were randomly allocated to four diets: corn-soybean meal-based diets supplemented with 0, 0.1, 0.5, or 1.0 g kg-1 levan-type fructan during this 42-day experiment. During days 0 to 21 and 0 to 42, average daily gain and average daily feed intake were linearly increased (P < 0.01) with increasing dietary levan-type fructan inclusion. The apparent total tract digestibility of dry matter, crude protein, and gross energy were linearly increased (P < 0.001) with increasing dietary levan-type fructan content. With increasing levels of levan-type fructan, faecal lactic acid bacteria counts were linearly increased (P = 0.001). The results indicate that dietary supplementation with increasing levan-type fructan enhanced growth performance, improved nutrient digestibility, and increased faecal lactic acid bacteria counts in weaning pigs linearly. © 2017 Society of Chemical Industry.

An analysis of the changes on intermediate products during the thermal processing of black garlic

The thermal processing of black garlic was simulated. Fresh garlic was incubated at 55°C with 80% humidity and sampled every 5 or 10days. The changes in relevant products were as follows: the fructan content was decreased by 84.79%, and the fructose content was increased by 508.11%. The contents of Maillard reaction intermediate products were first increased and then decreased. The colour of garlic gradually became dark and the pH decreased from 6.13 to 4.00. By analyzing these changes, the mechanism of black garlic formation and the changes on the Maillard reaction were revealed. The sweetness of black garlic resulted mainly from the fructose that was produced, and the black colour was largely due to the Maillard reaction between fructose/glucose and amino acids. An understanding of this process is useful to explain the formation mechanism of black garlic and could lead to better control of the quality of black garlic.

Ultrasound-assisted extraction of fructans from agave (Agave tequilana Weber var. azul) at different ultrasound powers and solid-liquid ratios

The effects of ultrasound-assisted extraction (UAE) at different ultrasound power densities (UPDs; 40, 80, and 120 mW/mL) and solid:liquid (S:L) ratio (1:2, 1:3, and 1:6) on the extraction of carbohydrates from Agave tequilana plant of different ages were evaluated. Extracts obtained (6- and 7-year-old plant) were analyzed in the yield of carbohydrates (YC), fructan (FRU) content, simple sugars, fructan profile and the average degree of polymerization (DPn). UPD, S:L ratio, and plant age all affected YC, FRU, and DPn. Maximum YC and FRU were obtained from the older agave with UPD and S:L ratio of 120 mW/mL and 1:6, respectively; while glucose, fructose, and sucrose were highly released from the younger plant. Agave of 7-year-old presented the highest DPn. Fructan degradation occurred at high UPD, increasing the simple sugars and decreasing the DPn. Thermal-traditional extraction without sonication caused more fructan degradation; and overall, ultrasound enhanced fructan extraction and minimized fructan damage, representing a technological alternative for fructan extraction from agave.

Stem carbohydrate dynamics and expression of genes involved in fructan accumulation and remobilization during grain growth in wheat (Triticum aestivum L.) genotypes with contrasting tolerance to water stress.

The genetic and physiological mechanisms underlying the relationship between water-soluble carbohydrates (WSC) and water stress tolerance are scarcely known. This study aimed to evaluate the main WSC in stems, and the expression of genes involved in fructan metabolism in wheat genotypes growing in a glasshouse with water stress (WS; 50% field capacity from heading) and full irrigation (FI; 100% field capacity). Eight wheat genotypes (five tolerant and three susceptible to water stress) were evaluated initially (experiment 1) and the two most contrasting genotypes in terms of WSC accumulation were evaluated in a subsequent experiment (experiment 2). Maximum accumulation of WSC occurred 10–20 days after anthesis. Under WS, the stress-tolerant genotype exhibited higher concentrations of WSC, glucose, fructose and fructan in the stems, compared to FI. In addition, the stress-tolerant genotype exhibited higher up-regulation of the fructan 1-fructosyltransferase B (1-FFTB) and fructan 1-exohydrolase w2 (1-FEHw2) genes, whereas the susceptible cultivar presented an up-regulation of the fructan 6-fructosyltransferase (6-SFT) and fructan 1-exohydrolase w3 (1-FEHw3) genes. Our results indicated clear differences in the pattern of WSC accumulation and the expression of genes regulating fructan metabolism between the tolerant and susceptible genotypes under WS.

Fructan reduction by downregulation of 1-SST in guayule

The natural rubber producing plant guayule (Parthenium argentatum Gray) stores carbohydrates mainly in the form of fructans, synthesized and stored in the same tissues at the same time as the rubber polymer, and a potential source of carbon for rubber biosynthesis. The first committed step to fructan synthesis is catalyzed by sucrose:sucrose-1-fructosyltransferase (1-SST), which was downregulated to test whether reduction of carbohydrate synthesis would divert carbon instead to rubber biosynthesis. Guayule leaf strips were transformed by Agrobacterium-mediated technology, and plants with downregulated 1-SST were evaluated in the laboratory and greenhouse. The plant tissue fructan concentration was reduced significantly, and sucrose concentration increased, especially in root tissues of greenhouse-grown plants. However, increased natural rubber production did not result.

Wheat Fructans: A Potential Breeding Target for Nutritionally Improved, Climate‐Resilient Varieties

Wheat (Triticum aestivum L.) is a widely consumed staple crop and essential component of a healthy whole‐grain diet. One component of wheat, fructans, is known to serve physiological roles in the plant and confer health benefits to humans. Fructans serve as reserve carbohydrates and osmotic regulators against stresses (i.e., drought, cold temperatures, and salinity) that affect grain yield in the wheat plant. For humans, fructans are prebiotics that promote growth of healthy gut bacteria, aid in immune support, reduce colon cancer incidence, and support bone health. While cereals are the main source of fructans in the American diet, fructans are found in many other plant foods. Variation in wheat grain fructan content has been observed with several widely accepted fructan quantification techniques. Given the observed variation in grain fructan content and potential physiological benefits of fructans for wheat plants and consumers, fructans are a potential breeding target for developing climate‐resilient, nutritionally improved wheat varieties.

Dual-Laboratory Validation of a Method for the Determination of Fructans in Infant Formula and Adult Nutritionals: First Action 2016.14.

Until recently, only two AOAC Official MethodsSM have been available for the analysis of fructans: Method 997.08 and Method 999.03. Both are based on the analysis of the fructan component monosaccharides (glucose and fructose) after hydrolysis. The two methods have some limitations due to the strategies used for removing background interferences (such as from sucrose, α-glucooligosaccharides, and free sugars). The method described in this paper has been developed to overcome those limitations. The method is largely based on Method 999.03 and uses combined enzymatic and SPE steps to remove the interfering components without impacting the final analytical result. The method has been validated in two laboratories on infant formula and adult nutritionals. Recoveries were in the range of 86-119%, with most being in the range of 91-104%. RSDr values were in the range of 0.7-2.6%, with one exception when the fructan concentration was close to the LOQ, resulting in an RSDr of 8.9%. The performance is generally within the requirements outlined in the AOAC Standard Method Performance Requirements (SMPR® 2014.002), which specifies recoveries in the range of 90-110% and RSDr values below 6%.