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1.
Native potato starch has been modified with allylglycidyl ether (AGE) under various reaction conditions including different sodium hydroxide and AGE concentrations, reaction temperatures and times. 1H‐NMR and FT‐IR were used to analyze the products. AGE‐modified starch, with two degrees of substitution (DS), namely DS = 1.3 and DS = 2.3, was synthesized and used for preparation of a new family of crosslinked composites reinforced with various amounts of bleached softwood fibres. Composite premixes of modified starch, wood fibres and ethylene glycol dimethacrylate (EGDA) were cured in a hot press using 2% (w/w) of benzoyl peroxide at 150°C under high pressure for 10 min. The matrix with high degree of substitution exhibited good processability and was easily processed even for the highest fibre contents, up to 70% (w/w). In addition, scanning electron micrographs showed good dispersion and adhesion between the starch matrix with high degree of substitution and fibre. The original poor mechanical properties of the cured modified starch were markedly improved by the addition of wood fibres. In the extractions tests cured high‐DS and low‐DS composite samples showed weight losses in the range of 1 and 15% (w/w), respectively. No unreacted crosslinker ethylene glycol dimethacrylate was detected in the solutes as determined by NMR. 相似文献
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Ming Miao Bo Jiang Zhengyu Jin James N. BeMiller 《Comprehensive Reviews in Food Science and Food Safety》2018,17(5):1238-1260
Starch is an abundant, natural, renewable resource, and present as the major storage carbohydrate in the seeds, roots, or tubers of many important food crops, such as maize, wheat, rice, potato, and cassava. Uses of native starches in most industrial applications are limited by their inherent properties. Hence, they are often structurally modified after isolation to enhance desirable attributes, to minimize undesirable attributes, or to create new attributes. Enzymatic, rather than chemical, approaches are used in the production of starch syrups, maltodextrins, and cyclodextrins. However, the desire for starch‐active enzymes working optimally at high temperatures and low pH conditions with superior stability and activity is still not satisfied and this stimulates interest in developing novel and improved starch‐active enzymes through a variety of strategies. This review provides current information on enzymes belonging to GH13, 57, 70, and 77 that can be used in structural modifications of the starch polysaccharides or to produce starch‐derived products from them. The characteristics and catalytic mechanisms of microbial enzymes are discussed (including 4‐α‐glucanotransferase, branching enzyme, maltogenic amylase, cyclomaltodextrinase, amylosucrase, and glucansucrase). Product diversity after starch‐converting reaction and utilization in industrial applications are also dealt with. 相似文献
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Carlos Gabriel Arp María Jimena Correa Ángela Zuleta Cristina Ferrero 《International Journal of Food Science & Technology》2017,52(2):550-558
Resistant starch can be used to reduce the availability of carbohydrates in baked products. In this study, the effect of type 4 resistant wheat starch (RS4) on wheat flour dough and breads was evaluated. Wheat flour was substituted by RS4 at 10%, 20% and 30% w/w (RS10, RS20 and RS30, respectively). Rheological and thermal behaviours of dough were evaluated. Besides, bread quality, starch digestibility and bread staling were analysed. All substituted dough exhibited viscoelastic behaviour but lower elastic and viscous moduli. Regarding to bread quality, specific volume and crumb texture were negatively affected in samples with RS4. However, all samples were technologically acceptable. During storage, crumb hardening was observed in breads without and with RS4 but amylopectin retrogradation was not particularly affected. The in vitro digestibility of bread with RS showed a lower release of reducing sugars and a lower estimated glycaemic index, suggesting a healthier profile for these breads. 相似文献
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Jiaying Liu Feitong Liu Seda Arıoğlu-Tuncil Zhuqing Xie Xiong Fu Qiang Huang Bin Zhang 《International Journal of Food Science & Technology》2022,57(5):2782-2792
In the present study, we prepared A- and B-type polymorph-resistant starch spherulites (RSSs) with a wide range of crystallinity, and elucidated the relation between crystalline structure and faecal microbial fermentation outcomes. A- and B-type polymorphic RSSs displayed similar fermentation rate throughout entire process with final gas production of 11.8–13.2 mL, suggesting that the crystalline pattern and crystallinity cannot effectively control the fermentation rate of starches. The acetate and butyrate concentration of A-type RSS decreased with the increase of crystallinity respectively, and highly crystalline B-type RSS reduced the production of acetate (8.4 mM) and propionate (2.1 mM). RSSs with different crystalline types showed similar microbial community structure but distinct key bacteria species. A-type RSSs greatly promoted the abundance of butyrogenic bacteria (i.e., Roseburia faecis and Lachnospiraceae), whereas B-type RSSs tended to proliferate Prevotella copri associated with propionate production. Our findings shed new light on design and manufacture of starch-based functional ingredients with enhanced gut health. 相似文献
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Cassava‐starch based polymer films containing glycerol as a plasticizer (1.0‐2.5‐5.0%, w/w) and different lipids as additives (paraffin, stearyl alcohol, and beeswax – 0.25‐0.5‐1.0%, w/w) were produced. Control films were produced by heating a mixture of glycerol, starch, and water, while treated films were produced by the addition of lipids/ ethanol solutions. The solutions were kept at around 70ºC during amalgamation, and once congealed, were placed in a vacuum oven for 1 h at 90ºC. The solutions were then spun on 7‐inch diameter non‐stick disks, allowed to dry, and conditioned at 23ºC and 50% RH before testing. Cassava starch‐glycerol‐beeswax films were successfully produced with a stable film structure at glycerol concentration equal or below 5% (w/w). Addition of glycerol and beeswax did not visually change the color of the films. Increasing glycerol content improved elongation while decreasing tensile strength. Increasing the glycerol concentration from 1.0 to 5.0% increased the water vapor permeability by 150% and addition of beeswax further increased these values by 250%. 相似文献
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Knud Erik Bach Knudsen Nuria Canibe 《Journal of the science of food and agriculture》2000,80(8):1253-1261
Cell wall materials from various cellular tissues of cereals may potentially influence the digestion and absorption processes in different ways. The objective of the present investigation was to study the breakdown of plant carbohydrates in the gastrointestinal tract of pigs fed a low‐fibre (LF; 65 g kg−1 dry matter) wheat flour‐based diet and two high‐fibre diets with added insoluble fibre from wheat bran (HFWB; 112 g kg−1 dry matter) or soluble fibre from oat bran (HFOB; 108 g kg−1 dry matter). The diets were formulated to provide ∼0.31 energy from fat, ∼0.18 energy from protein and ∼0.51 energy from carbohydrates and were offered as baked rolls to eight ileum‐cannulated hypercholesterolemic pigs in a crossover design. Carbohydrates were the predominant ileal constituent, with most of the carbohydrates present as non‐starch polysaccharides (NSP). Starch in all diets was almost completely digested at this site of the gastrointestinal tract, with digestibility values above 0.99. The ingested amount of NSP was quantitatively recovered in ileal materials with the wheat‐based diets, while there was a significant loss of 0.27 of NSP primarily as mixed linked (1→3)(1→4)‐‐D ‐glucan with diet HFOB. The concentration and flow of lactic acid were also highest in the ileum after feeding diet HFOB, indicating that ‐glucan stimulated lactic acid formation. Any soluble components that reached the large intestine were almost completely broken down, while the digestibility of insoluble NSP constituents was significantly lower for diets LF and HFWB than for diet HFOB. The high degradation of oat bran resulted in a lower effect on faecal dry and wet bulking than was found with wheat bran. In conclusion, cereal starch was practically completely degraded in the small intestine, while the site and extent of NSP degradation, lactic acid formation and bulking properties were influenced by the fibre source. © 2000 Society of Chemical Industry 相似文献
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Reducing the glycaemic index and increasing the slowly digestible starch content in gluten‐free cereal‐based foods: a review 下载免费PDF全文
Gianluca Giuberti Antonio Gallo 《International Journal of Food Science & Technology》2018,53(1):50-60
Commercially available gluten‐free (GF) cereal‐based foods are generally characterised by a lower nutritional quality than their gluten‐containing counterparts, relatively lower resistant starch (RS) content, along with higher glycaemic index (GI) often being reported. To overcome this nutritional imbalance, extensive research has been conducted to investigate the preparation of a new generation of staple GF products. This review reported the main strategies currently adopted in GF cereal‐based food recipes to formulate products with overall slowly digestible starch properties. They are mainly obtained by the utilisation of alternative ingredients to be incorporated into standard food formulation (including native starch and GF flours) or by technological treatments that may contribute to impact starch digestibility. Considering data from in vitro digestion trials, indications suggested that, aiming to obtain a RS content of about 5% (dry weight) and lowering the in vitro GI values, the minimum high amylose starch (amylose >60%) replacement level in GF bread and cookie formulations should be in the order of 20% by weight of total flours. Overall, with respect to un‐substituted GF foods, two‐ to three‐times higher RS contents, along with a parallel in vitro GI decrease (up to ?50%), were obtained for GF pasta and ready‐to‐eat snacks enriched with legume flours at inclusion levels from 40% to 100% by weight of total flours. The use of flours from pseudocereals (e.g., quinoa, amaranth and buckwheat) with and without sourdough did not always guarantee favourably slowly digestible starch GF foods. 相似文献
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Alejandro Aparicio‐Saguiln Emmanuel Flores‐Huicochea Juscelino Tovar Francisco García‐Surez Felipe Gutirrez‐Meraz Luis A. Bello‐Prez 《Starch - St?rke》2005,57(9):405-412
Powdered preparations enriched in resistant starch (RS) were obtained from native and lintnerized (prolonged acid treatment) banana starches by consecutive autoclaving/cooling treatments. The preparations were tested for indigestible starch content, swelling and solubility properties, thermal analysis and pasting profile. The autoclaved samples had higher RS content than their parental counterparts, but the chemical modification (lintnerization process) allowed development of higher RS proportions (19%, dry matter basis, dmb). The autoclaved samples (RS‐enriched products) showed similar swelling values (α = 0.05) at the temperatures assessed. These RS‐rich products exhibited a lower solubility in water than the corresponding raw materials. The peak temperatures of the thermal transition were 155.5 and 145.8°C for native autoclaved and lintnerized autoclaved starch, respectively. These values indicate that RS products have a marked thermal stability. The pasting behavior of the RS products was less pronounced than that of the raw counterparts. Hence, their potential use as processed food ingredients should not impact final product viscosity. These RS‐enriched products appear suitable for the formulation of functional foods. 相似文献
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The effect of galactomananns (guar gum and locust bean gum) at different concentrations (0, 0.2, 0.4, 0.6 and 0.8%, w/w) on the dynamic rheological properties of aqueous rice starch dispersions (5%, w/w) was investigated by small‐deformation oscillatory measurements during aging. Magnitudes of storage (G′) and loss (G′′) moduli measured at 4°C before aging increased with the increase in gum concentration in the range of 0.2–0.8%. G′ and G′′ values of rice starch‐locust bean gum (LBG) mixtures, in general, were higher than those of rice starch‐guar gum mixtures. G′ values of rice starch‐guar gum mixtures as a function of aging time (10 h) at 4°C increased rapidly at initial stage and then reached a plateau region at long aging times. However, G′ values of rice starch‐LBG mixtures increased steadily without showing a plateau region. Increasing the guar gum concentration resulted in an increase in plateau values. The rate constant (K) for structure development during aging was described by first‐order kinetics. K values in rice starch‐guar gum mixtures increased with the increase in guar gum concentration. G′ values of rice starch‐galactomannan mixtures after aging were greater than those before aging. 相似文献
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Xiuqiong Zhang Søren K. Rasmussen Xiaotong Jiang Wenjian Song Dianxing Wu Xiaoli Shu 《International Journal of Food Science & Technology》2018,53(4):1079-1086
To investigate the possibility of improving the quality of rice rich in resistant starch through operation of nonstarch polysaccharides, the high dietary fibre (7.24%) mutant cw and its wild‐type R7954 were selected to study the physiochemical characteristics of starch before and after removal of nonstarch polysaccharides. Results showed that hydrolysed or partially hydrolysed nonstarch polysaccharides in cw decreased the resistant starch content significantly, from 15.23% to 10.8%. Nonstarch polysaccharides had significant influences on the gelatinisation temperature, RVA parameters of R7954, but no significant influences on that of cw. For cw, removal of cellulose increased swelling power and adhesiveness, decreased the hardness significantly, from 0.3 to 0.23 N, while the resistant starch content was still as high as 13.72% and showed no significant difference from the wild type. This suggests that the influences of nonstarch polysaccharides on starch properties depend both on the type of rice and the nonstarch polysaccharides. Operation on nonstarch polysaccharides for obtaining rice with lower glycemic index is feasible, but operation on nonstarch polysaccharides may also be an alternative way of improving the palatability for rice high in resistant starch. 相似文献
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Increasing interests in the use of starch as biodegradable plastic materials demand, amongst others, accurate information on thermal properties of starch systems particularly in the processing of thermoplastic starch (TPS), where plasticisers (water and glycerol) are added. The specific heat capacity of starch‐water‐glycerol mixtures was determined within a temperature range of 40‐120 °C. A modulated temperature differential scanning calorimeter (MTDSC) was employed and regression equations were obtained to predict the specific heat capacity as a function of temperature, water and glycerol content for four maize starches of differing amylose content (0—85%). Generally, temperature and water content are directly proportional to the specific heat capacity of the systems, but the influence of glycerol content on the thermal property varied according to the starch type. 相似文献
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A synergetically acting new flocculant on the basis of starch‐graft‐poly(acrylamide)‐co‐sodium xanthate (CSAX) was synthesized by grafting copolymerization of crosslinked corn starch, acrylamide (AM), and sodium xanthate, using epichlorohydrin (EPI) as cross‐linking agent and ceric ammonium nitrate (CAN) as polymerization initiator in aqueous solution. The effects of some factors, such as crosslinker, initiator, AM, NaOH, on the %Tr (turbidity removal rate), %Trd (turbidity removal rate of a water sample which has both turbidity and heavy metal ions %Hr (heavy metal ion removal rate) and %Hrd (heavy metal ions removal rate of water which has both heavy metal ions and turbidity), are investigated. As proven by FTIR and elemental analysis, the CSAX can be successfully synthesized and can remove both turbidity‐causing substances and heavy metal ions from aqueous solutions. Under optimum synthesis conditions CSAX exhibits excellent performance, i.e. %Tr = 98%, %Trd = 98.4%, %Hrd = 99% and %Hr = 91.6%, respectively. 相似文献
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Alummoottil N. Jyothi Janardhanan Sreekumar Subramoney N. Moorthy Moothandaserry S. Sajeev 《Starch - St?rke》2010,62(1):18-27
Response surface methodology (RSM) was employed for the synthesis of cassava starch‐graft‐poly(acrylamide) using ceric ammonium nitrate as free radical initiator. Concentration of acrylamide, concentration of ceric ammonium nitrate, reaction temperature and duration of reaction were optimized using a 4‐factor 3‐level Box‐Behnken design. The dependent variables were percentage grafting (%G) and grafting efficiency (GE). Second order polynomial relationships were obtained for %G and GE, which explained the main, quadratic and interaction effects of factors. The highest%G and GE obtained were 174.8% and 90.7%, respectively. The optimum values of parameters predicted through RSM were 20 g acrylamide/10 g dry starch, 3.3 g/L ceric ammonium nitrate, 180 min reaction duration and 45ºC temperature with a %G of 190.0. For GE, the predicted levels of factors for the optimum value of 90.8% were 17.5 g acrylamide/10 g dry starch, 4.1 g/L ceric ammonium nitrate, 180 min reaction duration and 55ºC temperature. The graft reaction was confirmed by FTIR analysis, where the absorption bands corresponding to the C=O stretching and N‐H bending of the –CONH2 group were observed. Scanning electron microscopic studies on grafted starches revealed that the granular structure of the starch was affected by the reaction. X‐ray diffraction analysis showed that the crystallinity of starch was decreased as a result of grafting and the reduction was higher for the grafted starches with higher percentage grafting. 相似文献
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A.M. Osman 《Journal of the Institute of Brewing》2002,108(2):204-214
Existing methods of assay of malt starch‐degrading enzymes were critically appraised. New methods based on natural substrates, namely starch and its natural intermediate‐derivative, were developed for all the enzymes, except limit dextrinase for which pullulan was used. Thermostability, optimal temperatures and pHs were established. α‐Amylase and limit dextrinase were the most thermostable and β‐amylase, α‐glucosidase and maltase were the least stable while diastase occupied an intermediate position. The optimal temperatures were congruent with thermostability, β‐ amylase having the lowest (50°C) and α‐amylase the highest (65°C) with the remaining enzymes, including diastase, falling in between. In contrast, α‐amylase has the lowest optimal pH (pH 4.5) and β amylase the highest (pH 5.5) while the others have pHs in between the two values. The roles of the enzymes were evaluated taking into account the level of activity, thermostability, optimum pH, the nature of the product(s), and the relevance to brewing. β‐Amylase production of maltose was synergistically enhanced, mostly by α‐amylase but also limit dextrinase. α‐Glucosidase and maltase are unimportant for brewing, because of their low activity and the negative impact on β‐amylase activity and the negative effect of glucose on maltose uptake by yeast. The starch‐degrading enzymes (diastase) in a gram of malt were able to degrade more than 8 g boiled starch into reducing sugars in 10 min at 65°C. The latter, suggests that it will be possible to gelatinise most of the malt starch at a higher temperature and ensure its hydrolysis to fermentable sugars by mixing with smaller portions of malt and mashing at lower temperatures e.g. 50–60°C. 相似文献
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Prajongwate Satmalee Junko Matsuki 《International Journal of Food Science & Technology》2011,46(12):2628-2633
High and low amylose Thai rice flours (KC and ML, respectively) were used in this work, to increase the resistant starch (RS) content in the flour. Pullulanase debranching followed by heat‐moisture treatment (DHMT) altered the pasting properties, which increased the shear stability to the flours. The gelatinisation temperature determined by DSC was increased and the more retrogradation occurred in treated flour compared to the native flour. The SEM observation showed that the treatment did not change the morphology of the granules in both flours. The slowly digestible starch (SDS) content in DHMT KC was higher than in the native KC. The RS content in the treated ML flour was increased to 18.31% from 11.59% in native flour. These concluded that the treatment affected the digestibility, while maintaining the granular structure. 相似文献
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Many nutrition models rely on summative equations to estimate feed and diet energy concentrations. These models partition feed into nutrient fractions and multiply the fractions by their estimated true digestibility, and the digestible mass provided by each fraction is then summed and converted to an energy value. Nonfiber carbohydrate (NFC) is used in many models. Although it behaves as a nutritionally uniform fraction, it is a heterogeneous mixture of components. To reduce the heterogeneity, we partitioned NFC into starch and residual organic matter (ROM), which is calculated as 100 ? CP ? LCFA ? ash ? starch – NDF, where crude protein (CP), long-chain fatty acids (LCFA), ash, starch, and neutral detergent fiber (NDF) are a percentage of DM. However, the true digestibility of ROM is unknown, and because NDF is contaminated with both ash and CP, those components are subtracted twice. The effect of ash and CP contamination of NDF on in vivo digestibility of NDF and ROM was evaluated using data from 2 total-collection digestibility experiments using lactating dairy cows. Digestibility of NDF was greater when it was corrected for ash and CP than without correction. Conversely, ROM apparent digestibility decreased when NDF was corrected for contamination. Although correcting for contamination statistically increased NDF digestibility, the effect was small; the average increase was 3.4%. The decrease in ROM digestibility was 7.4%. True digestibility of ROM is needed to incorporate ROM into summative equations. Data from multiple digestibility experiments (38 diets) using dairy cows were collated, and ROM concentrations were regressed on concentration of digestible ROM (ROM was calculated without adjusting for ash and CP contamination). The estimated true digestibility coefficient of ROM was 0.96 (SE = 0.021), and metabolic fecal ROM was 3.43 g/100 g of dry matter intake (SE = 0.30). Using a smaller data set (7 diets), estimated true digestibility of ROM when calculated using NDF corrected for ash and CP contamination was 0.87 (SE = 0.025), and metabolic fecal ROM was 3.76 g/100 g (SE = 0.60). Regardless of NDF method, ROM exhibited nutritional uniformity. The ROM fraction also had lower errors associated with the estimated true digestibility and its metabolic fecal fraction than did NFC. Therefore, ROM may result in more accurate estimates of available energy if integrated into models. 相似文献