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The study investigated the improvement of slowly digestible starch fraction of cardaba banana via octenyl succinic anhydride (OSA) modification process. A nonlinear (Response surface methodology [RSM] and artificial neural network [ANN]) and linear (partial least square [PLS]) models were employed and their predictability was compared. The result revealed that all the modelling techniques were accurate in predicting the experimental process. The optimized RSM values for the production of slowly digestible starch (SDS) fraction were OSA concentration of 4%, reaction time of 47.49 min, and pH of 10 with a predicted SDS value of 44.64%. Among the modelling techniques, ANN was adjudged as the predictive model for improving the SDS yield. The regression coefficient coupled with the variable important in the projection (VIP) values of the PLS model indicated that the OSA concentration was the most important factors responsible for high SDS yield. Finally, a structural comparison of the optimized starch against native starch revealed the formation of high ordered crystalline structure of the starch due to the impregnation of the modifying agent to the hydroxyl group of the cardaba banana starch.

The industrial utilization of native starches is limited because of their poor qualities and different starch modifications are used to improve functionality of starch. Physical modification of starch is preferred since it is simple, inexpensive, and specially it does not involve any chemical reagents. Physical modifications can be divided into thermal and non-thermal treatments. These techniques alter physicochemical properties of starch including in vitro digestibility, which indicates the nutritional value of starch. Starch nutritional fractions are of three types; RDS (rapidly digestible starch), SDS (slowly digestible starch) and RS (resistant starch). It is important to understand how physical modifications affect starch nutritional fractions as both SDS and RS have beneficial health effects and specially RS has the potential to be used as a natural bioactive compound. This review aims to summarize the recent knowledge regarding the physical modifications and their impact on in vitro digestibility and nutritional fractions of starch.

The effect of heat moisture treatment (HMT), annealing (ANN), and dual retrogradation (DR) on functional and pasting properties, digestibility of starch components of banana flour comprising rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) has been investigated, using native banana flour (NBF) as a control. Crystal type, relative crystallinity and morphological changes were characterised by XRD and SEM. HMT has markedly modified the pasting properties and resulted in the highest SDS content. HMT and ANN increased the relative crystallinity but DR decreased it. HMT and DR altered XRD patterns from B to A and A + B type respectively, while ANN did not change the XRD patterns. The NBF compact granule surface remained unchanged with ANN but changed to a more porous surface with HMT and DR, thereby increasing the digestibility. Crystal type and granule morphology affected the digestibility while relative crystallinity might change the pasting point.

Objectives Maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si) are mucosal α-glucosidases required for the digestion of starch to glucose. We hypothesized that a dietary approach to reduce Mgam and Si activities can reduce glucose generation and absorption, and improve glucose control. Methods Rice starch was entrapped in alginate microspheres to moderate in vitro digestion properties. Three groups of 8-wk old mice (n = 8) were conditioned for 7 d with low 13C-starch-based materials differing in digestion rates (fast, slow, and slower), and then given a digestible 13C-labeled cornstarch test feeding to determine its digestion to glucose. Results Conditioning of the small intestine with the slowly digestible starches for 7 d reduced jejunal α-glucosidase and sucrase activities, as well as glucose absorption for the slowly digestible starch slower group (P Conclusions Decreased glucogenesis from a digestible starch feeding was found in mice conditioned on slowly digestible starch diets, suggesting that a dietary approach incorporating slowly digestible starches may change α-glucosidase activities to moderate glucose absorption rate.

With the increasingly extensive research on starch, its use in food, pharmaceutical and cosmetic industries has widely increased. This chapter summarizes the applications of starch towards edible films and coatings, the film forming abilities and recent advances in nano-composites were discussed. Starch has been used as functional ingredient in various food formulations for so many years, but currently starch from various sources is being studied and modified to improve its behavioral and functional properties. Besides this starch has also been widely used as encapsulating material for delivery of bioactive agents including probiotics, polyphenols minerals and vitamins. The use of starch for nano delivery of biomolecules and characterization of starch nanoparticles is currently of great interest for researchers.

In this study, rice starches from four cultivars: Baegokchal (BOC), Ilmi (IM), Mimyeon (MM), and Dodamssal (DDS), were studied in terms of their physicochemical and structural features. Native starches (NS) from MM and DDS showed high amylose content and low rapidly digestible starch, as well as high slowly digestible starch and resistant starch (RS) ratios. To elucidate the characteristics of RS in rice, non-digestible starches (NDS) were isolated from NS from each cultivar. The starch crystallinity of BOC, IM, and MM showed an A-type X-ray diffractometry pattern; however, DDS granules displayed a C-type crystallinity pattern with a predominant B-type. DDS starch granules had a convex spherical shape, whereas BOC, IM, and MM starch granules had a polygonal shape. All starches from IM and BOC were hydrolyzed, with no NDS residues remaining. The NDS from MM and DDS, which are high-amylose cultivars, showed a lower molecular weight, longer average amylopectin chain length, and lower viscosity than NS. DDS had the lowest digestibility, highest RS content, and showed potential for use as a source of starch for weight loss and hypoglycemic effects owing to its low glycemic index. The low viscosity of DDS can potentially be exploited for its use as a daily dietary component through the development of suitable processing methods for products such as rice noodles.

The structural and functional properties of slowly digestible starch (SDS) modified using pullulanase and prepared from chestnut starch were studied. The modified chestnut starches had 41.9 % SDS, which was higher than native chestnut starches (6.51 %) and cooked chestnut starches (18.6 %). The hydrolysis rate of the modified starches was 74.1 %. Scanning electron microscopy showed that the modified starch granules had a large surface area with signs of cracks and dents, and the cross-sections showed hollow internal structures. X-ray diffraction indicated that the crystallisation of the starch changed from the Cb-type to the V-type, although it retained a few C-type characteristics. Compared with native chestnut starch, the modified starches have a higher gelatinisation temperature using differential scanning calorimetry; and the texture profile analysis hardness, chewiness, cohesiveness, and gumminess of modified starch gels decreased significantly, while adhesiveness increased. When debranched using pullulanase there was a decreased solubility, swelling power, and freeze-thaw stability of the modified starches. These findings suggest that pullulanase modification changed the in vitro digestibility and crystalline structure of the modified starches.

The digestibility of starch in foods, which is influenced by the ingredients, formulation and preparation conditions, is a major determinant of glycaemic response. The terms rapidly digestible starch (RDS) and slowly digestible starch (SDS) along with the associated analytical methodology were developed by Englyst to characterise this nutritionally relevant food attribute. The measurement uncertainty of this starch digestibility method is evaluated here with an inter-laboratory trial. Six laboratories took part in the study testing ten cereal products with mean (range) contents of RDS: 48.4 g/100 g, (23.4–76·9) and, SDS: 10.9 g/100 g, (0.8–24.2). Based on the repeatability and reproducibility measurements, the calculated uncertainty was 3.6 g/100 g for RDS and 1.9 g/100 g for SDS. This trial has demonstrated acceptable measurement uncertainty and confirmed the transferability of the method between laboratories. The SDS content can identify foods rich in slow release carbohydrates with their associated health benefits.

The digestibility of starch is important for the nutritive value of staple food. Although several genes are responsible for resistant starch (RS) and slowly digestible starch (SDS), gaps persist concerning the molecular basis of RS and SDS formation due to the complex genetic mechanisms of starch digestibility. The objective of this study was to identify new genes for starch digestibility in rice and interprete the genetic mechanisms of RS and SDS by GWAS. Genome-wide association studies were conducted by associating the RS and SDS phenotypes of 104 re-sequenced rice lines to an SNP dataset of 2,288,867 sites using a compressed mixed linear model. Candidate genes were identified according to the position of the SNPs based on data from the MSU Rice Genome Annotation Project. Seven quantitative trait loci (QTLs) were detected to be associated with the RS content, among which the SNP 6 m1765761 was located on Waxy. Starch branching enzymes IIa (BEIIa) close to QTL qRS-I4 was detected and further identified as a specific candidate gene for RS in INDICA. Two QTLs were associated with SDS, and the LOC_Os09g09360 encoding lipase was identified as a causal gene for SDS. GWAS is a valid strategy to genetically dissect the formation of starch digestion properties in rice. RS formation in grains is dependent on the rice type; lipid might also contribute to starch digestibility and should be an alternative factor to improve rice starch digestibility.

A recent study showed that the digestion of glycemic carbohydrates in the distal part of the small intestine has the potential to regulate satiety and food intake levels. In this study, we investigated different processing methods (oil-frying and popping) of rice with citric-acid treatment for the efficient regulation of glucose production in small intestinal mucosal α-glucosidases. Glucose generation from citric-acid-treated rice products was drastically decreased due to the cross-linking of the starch molecules. Interestingly, oil-frying or popping under high-temperature and high-pressure conditions can be used to process rice or other cereals for gelatinizing starch molecules without water. Thus, various rice processing methods combined with citric-acid treatment can be used to develop rice or cereal-based food products, which can attenuate glucose spikes and extend glucose delivery.

The temperature-cycled retrogradation of rice starch used to prepare slowly digestible starch was investigated in this study. Our results showed that a maximum slowly digestible starch content of 51.62% was obtained from waxy rice starch at the optimal tested conditions: temperature cycles of 4/25 °C, at intervals of 24 h, and 7 days of storage. The results also indicated that there was a higher onset temperature ( T o ), a narrower melting temperature range ( T c − T o ), and a higher ratio (1047 cm −1 /1022 cm −1 ) of the slowly digestible starch products prepared under the temperature-cycled condition than that under the isothermal retrogradation. Furthermore, it was evident that the in vitro glycemic index of slowly digestible starch products with temperature-cycled retrogradation was reduced more than that with isothermal storage. These results suggest that the temperature-cycled retrogradation is applicable to prepare the high yield of slowly digestible starch from waxy rice starch.

Heat-moisture treatment (HMT) was optimised to increase the formation of slowly digestible starch (SDS) in waxy potato starch, and the structural and physiological properties of this starch were investigated. A maximum SDS content (41.8%) consistent with the expected value (40.1%) was obtained after 5 h 20 min at 120 °C with a 25.7% moisture level. Differential scanning calorimetry of HMT starches showed a broadened gelatinization temperature range and a shift in endothermal transition toward higher temperatures. After HMT, relative crystallinity decreased with increasing moisture level and X-ray diffraction patterns changed from B-type to a combination of B- and A-types. Hollow regions were found in the centres of HMT waxy potato starches. HMT intensity significantly influenced SDS level. This study showed that HMT-induced structural changes in waxy potato starch significantly affected its digestibility and the blood glucose levels of mice who consumed it.

Digestibility of starch in salmonids is reported to be highly variable and affected by a number of factors, such as source or type, dietary inclusion level, and technological treatments of the starch or feed. A model was constructed to explain variation in digestibility of starch across studies and to estimate digestible starch content of salmonid fish feed by integrating data from 26 studies. The relationship between digestible starch content and physico-chemical state (raw and gelatinized starch) was modelled through a multiple regression approach. Multiple regression analysis yielded the following model: Digestible starch content (% of diet) = 0.560 raw starch − 0.011 raw starch 2 + 0.904 gelatinized starch − 0.009 gelatinized starch 2 + 0.016 temperature * raw starch + 0.009 temperature * gelatinized starch − 0.270 fish species * raw starch − 0.068 * fish species * gelatinized starch − 0.158 * faeces collection method * gelatinized starch ( P R 2 = 0.84; fish species = 0 for rainbow trout, 1 for Atlantic salmon; faeces collection method = 0 for passive collection, 1 for active collection). The model suggests that the digestibility of raw and gelatinized starches significantly differs and their digestibility is negatively affected by dietary inclusion levels. The model also revealed a significant effect of water temperature on starch digestibility and interspecies differences in the ability to digest starch. Faeces collection method was found to significantly contribute to the variability of starch digestibility reported across studies. The model was validated by an independent group of data, and can potentially be a useful tool for feed formulation.

Previously, we have identified and characterized 4,6-α-glucanotransferase enzymes of the glycosyl hydrolase (GH) family 70 (GH70) that cleave (α1→4)-linkages in amylose and introduce (α1→6)-linkages in linear chains. The 4,6-α-glucanotransferase of Lactobacillus reuteri 121, for instance, converts amylose into an isomalto/malto-polysaccharide (IMMP) with 90% (α1→6)-linkages. Over the years, also, branching sucrase enzymes belonging to GH70 have been characterized. These enzymes use sucrose as a donor substrate to glucosylate dextran as an acceptor substrate, introducing single -(1→2,6)-α-d-Glcp-(1→6)- (Leuconostoc citreum enzyme) or -(1→3,6)-α-d-Glcp-(1→6)-branches (Leuconostoc citreum, Leuconostoc fallax, Lactobacillus kunkeei enzymes). In this work, we observed that the catalytic domain 2 of the L. kunkeei branching sucrase used not only dextran but also IMMP as the acceptor substrate, introducing -(1→3,6)-α-d-Glcp-(1→6)-branches. The products obtained have been structurally characterized in detail, revealing the addition of single (α1→3)-linked glucose units to IMMP (resulting in a comb-like structure). The in vitro digestibility of the various α-glucans was estimated with the glucose generation rate (GGR) assay that uses rat intestinal acetone powder to simulate the digestive enzymes in the upper intestine. Raw wheat starch is known to be a slowly digestible carbohydrate in mammals and was used as a benchmark control. Compared to raw wheat starch, IMMP and dextran showed reduced digestibility, with partially digestible and indigestible portions. Interestingly, the digestibility of the branching sucrase modified IMMP and dextran products considerably decreased with increasing percentages of (α1→3)-linkages present. The treatment of amylose with 4,6-α-glucanotransferase and branching sucrase/sucrose thus allowed for the synthesis of amylose/starch derived α-glucans with markedly reduced digestibility. These starch derived α-glucans may find applications in the food industry.

Nutraceuticals containing modified starch with increased content of slowly-digestible starch (SDS) may reduce the prevalence of obesity, diabetes and cardiovascular diseases due to its slow digestion rate. Enzymatic methods for the preparation of modified starch have attracted increasing attention because of their low environmental impact, safety and specificity. In this study, the efficient glucan branching enzyme McGBE from Microvirga sp. MC18 was identified, and its relevant properties as well as its potential for industrial starch modification were evaluated. The purified McGBE exhibited the highest specificity for potato starch, with a maximal specific activity of 791.21 U/mg. A time-dependent increase in the content of α-1,6 linkages from 3.0 to 6.0% was observed in McGBE-modified potato starch. The proportion of shorter chains (degree of polymerization, DP 13) increased from 29.2 to 63.29% after McGBE treatment, accompanied by a reduction of the medium length chains (DP 13-24) from 52.30 to 35.99% and longer chains (DP 25) from 18.51 to 0.72%. The reduction of the storage modulus (G') and retrogradation enthalpy (ΔHr) of potato starch with increasing treatment time demonstrated that McGBE could inhibit the short- and long-term retrogradation of starch. Under the optimal conditions, the SDS content of McGBE-modified potato starch increased by 65.8% compared to native potato starch. These results suggest that McGBE has great application potential for the preparation of modified starch with higher SDS content that is resistant to retrogradation.

Summary 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.

The effects of gelatinisation on slowly digestible (SDS) and resistant starch (RS) of native and modified canna starches were investigated. Starch slurries (10% w/w) were gelatinised at 100 °C for 5, 10, 20 and 40 min using a rapid visco analyzer (RVA). Significant change in the degree of gelatinisation (DG) values of all starch samples was observed during the initial 10 min of gelatinisation; after that the DG values increased gradually with gelatinisation time. The RS contents in all gelatinised starches decreased with increasing gelatinisation time, while the SDS values fluctuated. Chemical modification affected DG values as well as RS/SDS contents. The RS contents in 10% (w/w) acetylated, hydroxypropylated, octenyl succinylated and cross-linked canna starches gelatinised at 100 °C for 40 min were 26.6%, 32.0%, 45.3% and 19.8%, respectively, which were higher than that of the native starch (12.4%). Canna starch modified by crosslinking had the highest SDS content when gelatinised for 20–40 min. Modification of canna starch by heat-moisture treatment resulted in a lower content of RS for all treated samples. However, the Vt-HMT25 (canna starch containing moisture content of 25% during heat treatment) when gelatinised for 5–20 min contained a higher amount of SDS, compared to unmodified starch. The most effective modification method for RS and SDS formation was octenyl succinylation, where the sum of RS and SDS approached that of Novelose260.

The effect of a number of laboratory-scale pretreatments on the proportions of rapidly digested (RDS), slowly digested (SDS) and resistant starch (RS) in raw and cooked potato has been examined using an in vitro digestion procedure. Potatoes of the variety Frisia were prepared in three states: raw, cooked, and cooked followed by a cold treatment (4°C, two days). Each preparation was then subjected in triplicate to freeze-drying, coarsely mincing, pasting, freezing, dry-milling after freeze-drying, in 22 different combinations, before digesting. In raw potato, very little RDS and SDS ( 95% TS) in freshly-cooked potato, but after post-cooking cold treatment much of the RDS transformed to SDS, which reached a maximum of about 45% TS. SDS formation was independent of the degree of tissue disruption after cooking, and was generally associated with formation of RS, however, freezing after cooking allowed SDS formation without prolonged cold treatment and with very little associated RS (SDS 35% and RS 4% of TS). Freeze-drying caused an increase in RS in most treatments of the cooked potatoes. The observed effects provided guidance for sample handling in potato research, but also suggested several approaches to the enrichment of SDS and/or RS, with a concurrent reduction in RDS, that could be used to improve the nutritional profile of potato products by decreasing RDS (lowered glycaemic impact), and increasing SDS (more sustained energy availability) and RS (prebiotic benefits).

Starch is the main carbohydrate in human nutrition and offers a range of desired technological properties. The nutritional quality of starch strongly depends on starch structure and on its processing. Starch digestibility in the human small intestine can vary from a rapid digestion to indigestibility. However, the structural properties of the intermediate fraction of starch with slow digestibility and its potential health benefits are not well understood. The present review highlights current knowledge on starch structures causing a slow digestibility and explores their health implications.

Background Feeding behavior is controlled by satiety mechanisms, which are affected by the extent of starch digestion, and thus resistant starch (RS) intake. Alterations in feeding behavior to changes in RS intake may depend on the adaptation of processes involved when shifting from starch digestion to fermentation or vice versa. Objectives The aim of this study was to investigate how growing pigs adapt their feeding behavior in response to increasing and decreasing dietary RS concentrations. Methods Thirty-six groups of 6 pigs (25.4 ± 2.8 kg; Hypor Libra × Hypor Maxter; male:female, 1:1) were fed diets containing 50% high-amylose maize starch (high RS; HRS) or waxy maize starch (low RS; LRS). Over 28 d, diets were exchanged following a 5-step titration (25% per step) that was executed in the upward (LH) or downward direction (HL). Twelve groups received a control diet to correct for changes over time. Individual feeding behavior and total tract starch digestion and fermentation were evaluated. The response in each parameter to increasing dietary HRS inclusion was estimated through the use of linear regression procedures, and tested for titration direction and sex effects. Results Complete substitution of LRS with HRS increased the proportion of starch fermented, which was greater in LH pigs than in HL pigs (17.6% compared with 8.18%; P

We investigated dual modification of normal and waxy rice starch, focusing on digestibility. Amylosucrase (AS) was applied to maximize the slowly digestible and resistant starch fractions. AS-modified starches were adjusted to 25-40% moisture levels and heated at 100 °C for 40 min. AS-modified starches exhibited a B-type crystalline structure, and hydrothermal treatment (HTT) significantly (p0.05) increased the relative crystallinity with moisture level. The thermal transition properties of modified starches were also affected by the moisture level. The contents of rapidly digestible starch fraction in AS-modified normal and waxy starches (43.3 ± 3.9 and 18.1 ± 0.6%) decreased to 13.0 ± 1.0 and 0.3 ± 0.3% after HTT, accordingly increasing the low digestible fractions. Although the strengthened crystalline structures of AS-modified starches by HTT were not stable enough to maintain their rigidity under cooking, application of AS and HTT was more effective in waxy rice starch than normal rice starch when lowering digestibility.

High amylose rice starch was modified using a pyrodextrinization process under conditions designed to avoid gelatinization of starch. Rice starch was hydrolyzed with 0.5% HCl and 0.5% citric acid solution at 130 °C for 1 h (H1), 2 h (H2), and 3 h (H3) respectively. Hydrolyzed starches (25% moisture content) were then Heat moisture treatment (HMT) at 115 °C for 1 h. Pasting properties, swelling power, solubility, crystallinity and in vitro and in vivo starch digestibility were investigated. Pyrodextrinized-HMT rice starch was then used as wall material for tocopheryl acetate encapsulation by spray drying. The encapsulation capacity, microstructure, in vitro releasing property under simulated gastric (SGF) and intestinal fluid (SIF) were measured. Results show an insignificant increased in rapid digestible starch (RDS) after pyrodextrinization. SDS drastically decreased in proportion to the increase in RS content. Blood glucose responses in Wistar rats fed with pyrodextrinized-HMT starch were slower than those fed with native starch. The pyrodextrinized-HMT starch microcapsule showed higher encapsulation capacity, better resistance to in vitro digestibility, prolonged release in SGF but higher release in SIF without changing its crystalline patterns.

Slowly digestible starch (SDS) was prepared from rice starches physically modified by β-cyclodextrin (β-CD), maltosyl-β-CD, and hydroxypropyl-β-CD. Its thermal stability and crystalline properties were further explored, since such properties were important for SDS during heat processing. The results showed that the maximum percentage of remaining SDS was 78.2% for the starch physically modified by β-CD and subjected to dry heating for 15 min, and 73.7% for the starch subjected to moisture heating for 15 min. The starches physically modified by β-CD exhibited a higher peak melting temperature, conclusion temperature, and enthalpy change of melting than the control sample. The crystalline data indicated that the higher yield of SDS in the starch physically modified by β-CD could be attributed to a greater difference of partial V-type crystallites. More perfect crystallites and imperfect crystallites were formed, and designated as the major components of the SDS product. These findings suggest that the starch physically modified by β-CD had higher thermal stability because of the formation of VII-type crystallites, and was suitable for potential application during heat processing.

Starch is the major glycemic carbohydrate in foods, and its nutritional property is related to its rate and extent of digestion and absorption in the small intestine. A classification of starch into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) based on the in vitro Englyst test is used to specify the nutritional quality of starch. Both the RDS and RS fractions have been extensively studied while there are only limited studies on the intermediate starch fraction of SDS, particularly regarding its structural basis and slow digestion mechanism. The current understanding of SDS including its concept, measurement method, structural basis and mechanism, physiological consequences, and approaches to make SDS is reviewed. An in vivo method of extended glycemic index (EGI) is proposed to evaluate its metabolic effect and related health consequences.

The objective of this study was to obtain structure-digestion relationships of fully gelatinized starch. Twelve starch samples with marked fine structural differences (HPLC-SEC) were studied for their retrogradation behavior (thermal and rheological properties of starch gels) and in vitro digestibility. A reduction in the digestion rate during storage for 7 days was observed in all samples and, interestingly, this reduction was particularly evident in sago (64.7%), potato (57.3%), pea (55.1%) and acid-converted maize (ACM, 51.6-51.8 %) starches. Results indicated two potential interactions that may result in slowly digestible supramolecular structures: 1) double helices between external A and B1 chains of DP at peak maximum ≥ 15.5 Glucose Units (perhaps involving internal long chains) that also are prone to forming intermolecular associations [high relative drop in the storage modulus (G') during heating of 7 days-stored gels] and; 2) interactions of small molecular size acid-hydrolyzed starch molecules that may be more mobile and easily aligned.

Summary High-temperature high-pressure extrusion of sorghum–maize composite flour, of potential for healthy food manufacture, was investigated by factorial experimental design to determine the effect of level of sorghum in dry mix (15–60%); final barrel zone temperature (120–150 °C); total moisture in barrel (21.4–25.8%); total input rate (2.3–6.8 kg h−1); and screw speed (250–450 rpm) on extrudate slowly digestible starch (SDS), phenolic content, antioxidant capacity, protein digestibility, density and expansion ratio. Extrudate SDS increased with increasing sorghum level and decreased as the barrel temperature increased. Total phenolic content and antioxidant capacity were positively associated with sorghum level. Protein digestibility was associated negatively with sorghum level and positively with barrel temperature. Extrudate density was associated positively with total moisture and negatively with barrel temperature and input rate. Sorghum in dry mix, final barrel zone temperature and total moisture in barrel were the three most significant independent variables influencing extrudate dependant variables.

The relationship between the slow digestion property of cooked maize starch and its molecular fine structure was investigated. Results of the in vitro Englyst assay showed a range of rapidly digestible starch (RDS) (70.1-98.9%), slowly digestible starch (SDS) (0.2-20.3%), and resistant starch (RS) (0.0-13.7%) among the tested maize mutant flour samples. Further analysis showed that amylose content was significantly correlated ( R = 0.763, P0.001) with RS amount but not with that of SDS, indicating that amylopectin is the starch molecule associated with SDS. Total starch debranching analysis revealed a parabolic relationship between SDS content and the weight ratio of amylopectin short chains (DP13, named SF) to long chains (DP/= 13, named LF), which means amylopectin with a higher amount of either short chains or long chains can produce relatively high amounts of SDS. Furthermore, debranching analysis of the SDS materials from samples with the highest and lowest weight ratios of SF/LF (both had a high amount SDS) showed significantly different profiles, indicating there is not a uniform molecular structure for SDS. Thus, genetic mutants of maize samples have a good potential to provide raw starch materials of high nutritional quality. An additional finding showed that a simple and comparably high-throughput technique of Rapid Visco-Analyzer (RVA) can be used to screen genetic mutants on the basis of their RVA profiles.

The sweet potato is recognized as a health-promoting food, owing to its richness in functional components such as dietary fiber; however, only a few studies have been conducted on resistant starch (RS) levels in the sweet potato. Now, the sweet potato is expected to have potential as a renewable resource for bio-ethanol production. The enzymatic digestibility of raw starch appears to influence the conversion rate of starch to sugar in the first step of ethanol production. In this study, the RS content of gelatinized starch, digestible starch (DS) content of raw starch and other starch properties were investigated using 21 sweet potato cultivars and lines to assess varietal variations and to estimate relationships among these starch properties. The RS content of gelatinized starch ranged between 1.8 and 9.5%. The DS content of raw starch ranged between 69.3 and 98.3%. Analysis of variance indicated that the varietal differences were significant at the 0.1% level for both the RS content and the DS content. Sweet potato starches with high amylose content and low paste viscosity showed high RS content of gelatinized starch. Starches with low pasting temperature and slow retrogradation showed high DS content of raw starch. A new breeding line, Kyukei 03284-156, contained a unique starch having the highest RS content, highest amylose content, lowest paste viscosity and abnormal granule morphology. The results of this study are expected to provide useful information to food industries that utilize sweet potato starch and to breeders that attempt to improve the RS and DS contents in sweet potato cultivars.

The objective of this study was to investigate the structural characteristics of slowly digestible starch (SDS) and resistant starch (RS) fractions isolated from heat–moisture treated waxy potato starch. The waxy potato starch with 25.7% moisture content was heated at 120 °C for 5.3 h. Scanning electron micrographs of the cross sections of RS and SDS + RS fractions revealed a growth ring structure. The branch chain-length distribution of debranched amylopectin from the RS fraction had a higher proportion of long chains (DP ≥ 37) than the SDS + RS fraction. The X-ray diffraction intensities of RS and SDS + RS fractions were increased compared to the control. The SDS + RS fraction showed a lower gelatinization enthalpy than the control while the RS fraction had a higher value than the SDS + RS fraction. In this study we showed the RS fraction is composed mainly of crystalline structure and the SDS fraction consists of weak crystallites and amorphous regions.

A rapid enzymatic method for simultaneous determination of digestible and resistant starch in standards and foods is presented. The procedure for the determination of the digestible starch fraction was optimized. The main steps of this were: the removal of digestible starch, the hydrolysis of products and quantification of digestible starch as released glucose. Stomach and intestine physiological conditions (pH, transit time) are simulated approximately. The method was evaluated by the analysis of the starch content in various standards and raw foods. The method has showed a high precision and a good accuracy. Some variables, such as employment of sodium azide, incubation time of α-amylase and amyloglucosidase amount, which might affect the levels of digestible and resistant starch are also evaluated and discussed.

The first nonmilk foods that are given to infants contain high levels of starch, a fraction of which is resistant to enzyme hydrolysis. Incomplete digestion of starch may interfere with the absorption of certain minerals. A fraction of dietary starch which is resistant to in vitro enzymatic hydrolysis has been termed resistant starch. The aim of this study was to compare the intestinal apparent absorption of calcium, phosphorus, iron, and zinc in the presence of either resistant or digestible starch. Twelve 7-10-d-old piglets were fitted with a T-tube inserted into the intestine approximately 3 m distal to the duodenum. Animals received in random order 200 mL of a test meal of cooked, cooled, high amylose corn starch (16.4% resistant starch), or cooked rice starch (digestible starch) administered by an orogastric tube. Both meals contained the same amount of calcium, phosphorus, iron, and zinc. The test meal also contained tracer amounts of 59Fe and 65Zn, as well as polyethylene glycol 3350, as a nonabsorbable marker. Intestinal apparent absorption of starch was greater the meal with digestible starch (71.0 +/- 17.0%) than after the meal with resistant starch (49.2 +/- 10.3) (p < 0.001). After feeding the meals with resistant and digestible starch, mineral apparent absorption was, respectively: calcium, 40.2 +/- 11.8% versus 28.1 +/- 16.4% (p < 0.05); phosphorus, 73.2 +/- 14.0% versus 67.8 +/- 18% (NS); iron, 24.1 +/- 12.2% versus 12.6 +/- 10.6% (p < 0.01), and zinc, 35.0 +/- 13.0% versus 30.6 +/- 8.22% (NS). In conclusion, a meal containing 16.4% resistant starch resulted in a greater apparent absorption of calcium and iron compared with a completely digestible starch meal. If this finding holds true for the whole bowel, administration of resistant starches could have a positive effect on intestinal calcium and iron absorption.

This study aimed to evaluate the effect of gamma irradiation at dose levels of 0, 1, 3 and 5kGy on the chemical composition, starch digestibility, pasting properties and cooking properties of two varieties of polished rice (Sakha104 and basmati). The results showed that the highest dose of gamma irradiation decreased the apparent amylose content, peak viscosity water absorption and minimum cooking time; while the fat absorption and solid loss were slightly increased. Irradiation showed increases in rabidly digestible starch (RDS) and slowly digestible starch (SDS), with consequent reductions in resistant starch (RS) for Sakha104variety. Furthermore, basmati rice displays a linear behavior over the range of radiation doses for RDS and SDS with a reduction in RS.

Starch is one of the most common and abundantly found carbohydrates in cereals, roots, legumes, and some fruits. It is a tasteless, colorless, and odorless source of energy that is present in the amyloplasts of plants. Native starch comprises amylose, a linear α-glucan having α-1,4-linkage and amylopectin, a branched polysaccharide with both α-1,4-linkage and α-1,6-linkage. Due to the low solubility, high viscosity, and unstable pasting property of native starch, it has been restricted from its application in industries. Although native starch has been widely used in various industries, modification of the same by various chemical, enzymatic and physical methods have been carried out to alter its properties for better performance in several industrial aspects. Physical modification like gamma radiation is frequently used as it is rapid, penetrates deeper, less toxic, and cost-effective. Starch when irradiated with gamma rays is observed to produce free radicals, generate sugars owing to cleavage of amylopectin branches, and exhibit variation in enzymatic digestion, amylose content, morphology, crystallinity, thermal property, and chemical composition. These physicochemical properties of the starch due to gamma radiation are assessed using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and its application are discussed., Graphical abstract Image 1, Highlights • Assessment and comparison of morphological features of native and gamma-irradiated starch. • Investigation of crystallinity and structural type of crystalline domains through XRD. • FTIR spectroscopy confirmed the changes in chemical composition of gamma-irradiated and native starch. • DSC analysis revealed the changes in gelatinization temperature of gamma-irradiated and native starch.

Simiao rice is a variety of long-grain Indica rice popular in South China. However, researches on the milling technology of Simiao rice are limited. The effect of different degrees of milling (DOMs) of Simiao rice (0–12%) were evaluated in terms of the physicochemical properties and in vitro starch digestibility of the rice. The results showed that, as the DOM increased from 0 to 12%, the head rice yield (HRY) and the content of protein, lipid, dietary fiber, vitamin B1, vitamin E and niacin nonlinearly decreased, while the content of total starch and amylose and paste viscosity parameters nonlinearly increased. The differences in chemical constituents between the brown and milled Simiao rice with different DOMs lead to the variation in their pasting properties and in vitro digestibility. Because of lower content of slowly digestible starch (SDS) and resistant starch (RS), milled Simiao rice exhibited greater digestibility and a higher estimated glycaemic index (EGI). The EGI of Simiao rice ranged from 77.98 to 85.55, and remained almost constant (approximately 84) when the DOM was above 4%. Correlation analysis indicated that the EGI had strong negative correlations with lipid, protein, dietary fiber and RS, but a positive correlation with amylose. These results provide theoretical guidance for the production of Simiao rice with desired physicochemical properties and digestibility by adjusting the DOM.

Effects of repeated heat-moisture treatment (RHM) and continuous heat-moisture treatment (CHM) on structural, physicochemical, and digestibility properties of mung bean starch were investigated. Rupture and scallops appeared on the surface of starch granules and some polarization cross disappeared after CHM and RHM. Besides, CHM starch exhibited severe rupture than RHM with the same treatment time. Crystal type of CHM and RHM starch maintained A-type while crystallinity decreased first but then increased as treating time increased. Besides, the relative crystallinity, transition temperatures, ΔH, and slowly digestible starch and rapidly digestible starch content of RHM were significantly higher than CHM whereas solubility, swelling power, and pasting viscosities of RHM samples were lower than CHM under the same treating time. Overall, RHM measures have more advantages than CHM in the modification of the structural, physicochemical, and digestibility properties of starch.

Due to nonuniform maturation, some plants may not be at the recommended stage of maturity when preharvest glyphosate is applied. The objective of this study was to determine how preharvest glyphosate timing affects wheat starch physicochemical properties. Two wheat cultivars were grown in three locations, and glyphosate was applied at the soft dough stage (early application) and the ripe stage (commercial standard). Upon harvest, starch chemical characteristics were studied. The proportion of B-type starch granules was lower in treated samples, although the starch molecular weight was not affected. Rapidly digestible starch content was highest when glyphosate was applied at the ripe stage, and lowest in the control, and vice versa for slowly digestible starch. Additionally, flour pasting viscosity was significantly higher in samples treated at the soft dough stage. Overall, the effects on wheat starch physicochemical characteristics were more pronounced when glyphosate was applied at the soft dough stage of maturity.

Physicochemical, functional, and nutritional properties of flours from six navy bean varieties cultivated in two different locations in Manitoba, Canada were evaluated. The effect of genotype was found insignificant for protein content, ash content, zeta potential, and surface hydrophobicity among physicochemical properties (p > 0.05). For protein content, total starch content, and zeta potential of navy bean flours, environmental factors were found significant (p 0.05). In vitro protein digestibility results varied by genotype. Although in vitro protein digestibility corrected amino acid score values were significantly affected by genotype, environment, and their interactions similar to slowly digestible starch. The current study established a better understanding of the varietal effects of genotype and environment on a wide range of properties of navy bean flours.

BACKGROUND: There is a growing interest to increase dietary fiber (DF) consumption due to the health benefits associated with this nutrient. Pulses are considered a good source of non-digestible carbohydrates. The aim of this study was to investigate the possibility of substituting semolina with chickpea flour to increase the indigestible carbohydrate content without altering the texture of the pasta.RESULTS: Pasta was prepared by extruding semolina: chickpea blends. The protein and DF contents in the cooked pasta increased with the chickpea level with an important contribution of resistant starch (RS) to the DF values. The optimum cooking time decreased as the chickpea content increased, which was related to the degree of starch gelatinization of the raw pasta. The in vitro digestible starch content decreased with the chickpea substitution level, concomitant with the increase in the RS content. In general, the texture of the chickpea-containing pasta was similar to that of semolina pasta.CONCLUSIONS: Pending acceptability studies on these pastas may grant their promotion as good fiber sources, probably helpful in the fight against obesity and diet-related non-communicable diseases. This article is protected by copyright. All rights reserved. (Less)

Colored brown rice shows better health benefits than polished rice, and there is great interest in the design of demanded cooking manners for brown rice. This investigation concerns how the change of cooking mode can slow starch digestion of colored brown rice by inspecting mainly starch structural changes during cooking. Compared to cooking Mode 1, the soaking of Mode 2, at higher temperature, probably enhanced water diffusion into rice matrices, thus strengthening starch lamellae without apparently altering rice morphology and ordered structures such as starch polymorphs and helices. The followed heating of Mode 2, with reduced time, more sufficiently disrupted rice structures, causing less prominent nonperiodic molecular organizations. At the final cooking stage, the braising of Mode 2, having faster temperature reduction for prolonged time, leading to similar rice morphology, reduced molecular orders (e.g., helices) and probably denser amorphous regions of nonperiodic organizations. Such features tended to increase packing density of molecular chains (mainly starch) in rice matrices, thus slowing the enzyme diffusion in rice matrices and associated binding and catalysis events. In this way, a reduced starch digestion rate and increased resistant starch (RS) and slowly digestible starch (SDS) were seen for the rice following Mode 2 cooking.

Composite biscuits made of heat-moisture-treated banana flour and wheat flour with ratio ranging from 25 to 75% were characterized for its postprandial glucose response in mice, diffraction pattern by X-ray diffraction, organoleptic and texture properties. Biscuit made of 100% wheat flour was used as a control. Composite biscuits resulted in lower blood glucose response, lower glycemic index and load due to its resistant starch and slowly digestible starch content as well as lipid-starch complex. Composite biscuit made of 75% banana flour is potential to use as a source for long lasting energy product as it displayed stable blood glucose response for 4 hours. Among sensory attributes, color and taste of biscuits were the most sensitive to the addition of the banana flour. The difference in the hardness of biscuits using instrumental analysis did not significantly affect the acceptability of texture perceived by consumers except at 75% of the banana flour.

Aim of this work was to evaluate the impact of bread enrichment with different concentrations of lentil flour (LF) (0 g/100g, 10 g/100g and 20 g/100g) on some physico-chemical, structural, and nutritional features of bread. The addition of LF in formulation affected its properties, leading to a darker appearance and to a more compact structure (e.g., higher density and lower gas bubble area fraction). Besides, it led to a significant rise in the protein, free glucose, and rapidly digestible starch content as well as in the expected glycemic index. Concerning the investigation of nutritional properties, starch and protein digestibility has been evaluated by the combination of different digestion models. Each type of bread was subjected to an in vivo oral phase followed by a semi-dynamic in vitro gastrointestinal digestion. During the oral and the gastric phases of digestion, bread with the greatest LF content (20 g/100g) exhibited an extensive starch digestibility and a partial protein digestibility compared to the other samples, due to its higher protein content. In contrast, during the intestinal phase, control (0 g/100g) showed a stronger starch digestibility compared with the LF samples, while no differences could be observed in terms of protein digestibility investigated by SDS-PAGE., This work has received financial support from project PID2019-107663RB-I00 from the Spanish Ministry of Science and Innovation (MICINN).

The present study compared liquid sourdough technology with baker’s yeast leavening when applied to the production of a semolina-based crispy flatbread. Following in vitro starch digestion, the results revealed the sourdough leavened flatbread to contain a lower percentage of rapidly digestible starch (16%), higher amounts of slowly digestible starch (27%) and inaccessible digestible starch (4.1%) compared with the baker’s yeast leavened flatbread (20, 20, and 2.4%, respectively), making the former nutritionally healthier. The sourdough leavened bread was crispier, stiffer and more solid, as shown by texture analyses, although Raman spectroscopy revealed no differences in the crystallinity status of starch. The descriptive analyses show that the use of sourdough enhances the positive sensory traits, as rated by the consumer panel scores (6.08 vs. 5.56). In summary, the results indicate that the implementation of sourdough technology in the production of flat crispy breads could confer economic advantages to this product. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10068-018-0530-y) contains supplementary material, which is available to authorized users.

To understand the mechanisms of buckwheat digestion, in vitro and in vivo digestibility of buckwheat flour (BF), buckwheat starch (BS), defatted buckwheat flour (DFBF), and deproteinized buckwheat flour (DPBF) were investigated. The results showed that fat and protein could inhibit the digestion of BS. The resistant starch content of DFBF was decreased from 4.21% to 0.83%, and slowly digestible starch content was increased from 0.66% to 8.16%, compared with BF. The in vivo digestibility results showed that DFBF or DPBF has a shorter glucose release time and higher hepatic glycogen content than BF. Scanning electron microscopy and thermodynamic properties analyses were combined to study the interaction of starch, fat, and protein of buckwheat. These results indicated that proteins could wrap around the starch granules and limit the enzymolysis of starch. Fat-starch complex limited starch hydrolysis. This study could give good guidance for making new health care products.

Dyslipidemia, a major risk factor for cardiovascular diseases (CVDs), is modifiable by diet and lifestyle changes. A large population with mild to moderate dyslipidemia is at risk of developing CVDs, and early initiation of preventive measures can avert advancing into severe medical conditions. Studies suggest increasing slowly digestible starch (SDS) in diets can help lower blood lipids. We processed dehulled adlay, a cereal rich in bioactive compounds, such as polyphenols and phytosterols, into an instant meal by extrusion and milling and then assessed its starch composition and in vitro digestibility. The dehulled adlay was found to consist of 32% SDS and resistant starch combined. Then, eligible subjects with dyslipidemia were recruited to explore the adlay’s hypolipidemic potential, safety, and acceptability. Subjects consumed the dehulled adlay as the sole carbohydrate source in their breakfast, without changing other components in the diet or lifestyle, for 12 weeks. After intervention, serum total cholesterol (TC) decreased significantly in subjects with hypercholesterolemia. In addition, both TC and triglyceride levels decreased significantly in those above 50 years old. In conclusion, the extruded dehulled adlay displays potential for favorably modulating blood lipids, and the effect is more pronounced in the middle-aged population.

The functionalities of gluten-free rice noodles are significantly affected by starch hierarchical structures. Identifying the structures that synergistically determine noodle integrated functionalities is vital to designing health-promoting starchy foods with desirable consumer sensory and nutritional qualities. This study reports on the changes in starch structures and functionalities (starch digestibility, texture, and flavor) of rice noodles during household cooking processes (steaming, boiling, and stir-frying), and describes an underlying structure-functionality relationship. Results show that all the cooking processes examined increased starch reassembled ordered structures, especially short-range ordered structures, helical and crystalline structures, and ordered aggregate structures. Steaming and boiling led to a decrease in rapidly digestible starch (RDS) and an increase in slowly digestible starch, while stir-frying yielded a reduction in RDS content and an increase in resistant starch in rice noodles. Steaming and boiling decreased while stir-frying increased the flavor variety of noodles. All cooking processes examined altered noodle textures, with a significant increase in hardness, gumminess, and chewiness. Structure-functionality relationships suggested short-range ordered structures, crystalline structures, and the ordered molecular and aggregate structures of noodles synergistically determined starch digestion, texture, and flavor. By structuring such key structures, the digestion, texture, and flavor of rice noodles can thus be reasonably controlled.

The effects of the dry heat treatment (DHT) temperature (20, 50, 100, 150, 200 °C) on the structure of wheat flour and on the texture and in vitro starch digestibility of breads were investigated. X-ray diffraction and FTIR showed that increasing temperatures produced reduction of the hydrated starch structures, increased crystallinity and molecular order of starch chains, and had important effects on the gluten secondary structure. High treatment temperatures produced significant reductions in rapidly digestible starch (RDS) (53.21% at 20 °C, 22.24% at 200 °C), and the slowly digestible starch fraction tended to increase (26.12% at 20 °C, 31.48% at 200 °C). On the other hand, bread hardness showed a significant increase from 11.25 N at 20 °C to 49.53 N at 200 °C, the latter value being similar to that reported for bread crusts. Principal component analysis results showed that the flour and bread characteristics were drastically changed by the DHT, with 100 °C representing a critical temperature. Below 100 °C, breads showed textural characteristics close to that of the control bread, with reduced RDS fractions, while at temperatures above 100 °C, hardness was boosted.

Fresh pasta was formulated by replacing wheat semolina with 0, 5, 10, and 15 g/100 g (w/w) of Moringa oleifera L. leaf powder (MOLP). The samples (i.e., M0, M5, M10, and M15 as a function of the substitution level) were cooked by boiling. The changes in the phenolic bioaccessibility and the in vitro starch digestibility were considered. On the cooked-to-optimum samples, by means of ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) mass spectrometry, 152 polyphenols were putatively annotated with the greatest content recorded for M15 pasta, being 2.19 mg/g dry matter (p < 0.05). Multivariate statistics showed that stigmastanol ferulate (VIP score = 1.22) followed by isomeric forms of kaempferol (VIP scores = 1.19) and other phenolic acids (i.e., schottenol/sitosterol ferulate and 24-methylcholestanol ferulate) were the most affected compounds through the in vitro static digestion process. The inclusion of different levels of MOLP in the recipe increased the slowly digestible starch fractions and decreased the rapidly digestible starch fractions and the starch hydrolysis index of the cooked-to-optimum samples. The present results showed that MOLP could be considered a promising ingredient in fresh pasta formulation.

To date, how the pH conditions of thermal processing tailor the structure and digestibility of resulting starch-based complexes remains largely unclear. Here, indica rice starch (IRS), stearic acid (SA), and a whey protein isolate (WPI) were used as materials. Increasing the pH value from 4 to 8 during thermal processing (pasting) mainly suppressed the starch digestion of starch-WPI-SA complexes rather than starch-SA counterparts. The starch-SA complexes showed moderate structural changes as the pH value rose, and there was less rapidly digestible starch (RDS) only at pH 8. For the starch-WPI-SA complexes, an increased pH value allowed larger nonperiodic structures and more V-type starch crystallites, with almost unchanged short-range orders but apparently collapsed networks at pH 8. Such ternary complexes displayed more resistant starch (RS) as the pH value rose. The ternary sample at pH 8 contained ca. 29.87% of the RS fractions.

Several grains such as wheat, rice, corn, oat, barley and rye are cultivated throughout the world. They are converted to variety of food products using a multitude of processing technologies to quench the growing organoleptic demands and consumers' preferences. Among them, corn, ranking third in wide consumption, is cost-effective and has long-term storability. Herein, ready-to-eat corn flours with variable starch digestion have been developed by processing at high temperature with shear using a twin screw continuous processor. The influence of processing temperature (121, 145 and 160°C) and moisture (25, 30 and 35%) has been studied. Results suggest both processing temperature and moisture modulate the rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) amounts of the flours. The presence or absence of oil in the flour further controls the starch digestion. The outcome is deemed to be helpful to design and develop healthy and palatable functional food products in addition to furthering the current market share for corn and other grains.

The aim of this study was to investigate the effect of mechanical kneading and ‘absit’ preparation difference on the quality of tef injera, the staple food of Ethiopians. Standard methods were adopted to determine the starch fraction, total phenol, flavonoid, phytate and tannins of injera. Sensory injera quality was assessed using 9-point-hedonic scale. Change in kneading conditions (time/speed) did not significantly affect the free sugar (FSG), slowly digestible starch (SDS), resistant starch (RS), total starch(TS) and starch digestion rate index (SDRI). On the other hand, significant variation was observed in rapidly available glucose and rapidly digestible starch (RAG and RDS). Flavonoids, total phenolics and phytate contents varied significantly at different kneading time- speed combinations. Injera sensory quality was also significantly affected due to change in kneading conditions. Kneading condition 5 (3 min at speed 6) has the highest injera overall acceptability while kneading condition 9 (7 min at speed 12) had the lowest. In addition to kneading conditions, absit preparation (water to fermented dough ratio) was also found to affect the quality of tefinjera. Absit # 3 made from 100 ml of fermented dough and 900 ml of water had the highest injera overall acceptability while, the lowest was observed on Absit # 4 made from 300 ml of fermented dough and 100 ml of water. In conclusion, both kneading and absit preparation significantly influenced starch hydrolysis, flavonoids, total phenolics and phytate contents as well as sensory quality of injera. Key words: Kneading, sensory quality, absit preparation, starch fractions.