Slowly Digestible Starch Content Research Articles

Physicochemical Characterization of In Situ Annealed Starch and Its Application in a Fermented Dairy Beverage

In this study, the aim was to modify the starches of three different sweet potato varieties—Rosada Uruguaiana (RU), Rosada Canadense (RC), and Ligeirinha (L)—through in situ annealing to increase the content of slowly digestible starch (SDS), which has health benefits. The modified carbohydrate was then added to a dairy beverage fermented by Lactobacillus casei 1e (L. casei). After annealing, the starches had different physicochemical properties, and the L variety, which had the highest SDS content, was chosen for the formulation of the fermented dairy beverage. Two concentrations of modified starch (7% and 10.5%) were used in the formulations, and a sensory analysis indicated no differences in acceptance and purchase intention. The beverage containing 10.5% modified starch exhibited good physicochemical and microbiological stability. This study demonstrates the possibility of creating a functional fermented dairy beverage with high SDS content, which could potentially benefit consumers’ health.

Comparison and inhibition mechanism study on the in vitro digestibility of rice starch complex with soy β-conglycinin and soy glycinin

To inhibit the digestion of indica rice starch (IRS), an excellent strategy was to add exogenous proteins that interact with IRS, which was closely associated with the protein components. Herein, this study compared the effects of soy protein subfractions, soy β-conglycinin (7S) and soy glycinin (11S), on IRS digestion and explored its inhibition mechanisms. This study used hydrothermal processing to prepare IRS complexes with soy protein subfractions (7S and 11S) at different starch-protein ratios. The results found that adding 7S and 11S exhibited different inhibitory patterns on starch digestion. Compared to IRS, a higher slowly digestible starch (SDS) content (40.91%, p < 0.05) was observed at the IRS-7S ratios of 20:8, while the 20:6 IRS-11S complex showed a higher resistant starch (RS) content (15.76%, p < 0.05). Subsequently, the interactions between IRS and soy protein subfractions and their multi-scale structural changes were explored. The rheological results revealed that hydrophobic interaction and hydrogen bonding were the main driving forces. Various structural changes were closely associated with inhibitory modes of soy protein subfractions on IRS digestion. In detail, the increased SDS content in IRS-7S complexes was attributed to the formation of compact protein physical barriers, aggregated structures with more ordered regions, and flexible secondary conformations of 7S. However, the high-density structures and the stable secondary conformations of 11S were responsible for the increased RS content in IRS-11S complexes. Thus, this study could provide directions for developing SDS-enriched or RS-enriched starch-based products.

Effect of hydrolysis of sweet potato starch by pullulanase enzyme on the formation of slowly digestible starch

The benefits of slowly digestible starch (SDS) are a slow or moderate increase in postprandial blood glucose levels and the maintenance of steady blood glucose levels. These created good conditions for diabetes control, satiety-hunger, physical and mental performance. Therefore, products related to slow digestion have attracted many researchers in recent years. In this research, technological factors affecting the formation of SDS from sweet potato starch (SPS) by the branching enzyme pullulanase were studied. These factors included SPS concentration, pullulanase enzyme concentration, pH, temperature, and hydrolysis time of pullulanase enzyme. The results showed that the maximum SDS yield was obtained by debranching for 5 hrs with an enzyme concentration of 20 ASPU/g, reaction temperature of 55°C, pH of 5.0, and a SPS concentration of 10% (w/w). In these conditions, the SDS content of SPS reached 28.04%. The findings indicated that sweet potato starch can be used as a raw material at a low cost and is feasible in the production of SDS which provides benefits for human health.

Effect of amylose content and crystal type on the structure and digestibility of starch-fatty acid complex nanoparticle

To understand how amylose content and crystal type regulated the digestibility of starch–lipid complex nanoparticles, this study used waxy corn starch (WCS), normal corn starch (NCS) and high-amylose corn starch (HCS) with different amylose contents and NCS (A-type), potato starch (PtS, B-type) and pea starch (PS, C-type) with different crystal types to investigate the effects of amylose content and crystal type on the structure and digestibility of starch-lauric acid (LA) complex nanoparticles. A significant increase in complex index (CI), R1047/1022, relative crystallinity, and enthalpy of gelatinization (ΔH) was found in starch-LA complex nanoparticles with amylose contents increasing. The increases in resistant starch (RS) and slowly digestible starch (SDS) contents of WCS-LA complex nanoparticles, NCS-LA complex nanoparticles and HCS-LA complex nanoparticles were 29.33%, 40.29% and 93.90% compared to their respective controls. Furthermore, PtS-LA complex nanoparticles (PtS-LANPs) showed the highest increase in CI, R1047/1022, relative crystallinity, and ΔH compared to NCS-LA complex nanoparticles (NCS–LANPs) and PS-LA complex nanoparticles (PS-LANPs). For RS and SDS contents, the highest increased was found in PtS-LANPs (56.99%), followed by NCS–LANPs (40.29%) and PS-LANPs (31.44%) as compared to their respective controls. Results could provide basic data to prepare starch–lipid complex nanoparticles with desired digestibility.

Evaluating the effect of different physical pretreatments and cooking methods on nutritional (starch digestibility) and physicochemical properties of white rice grains (Fajr cultivar)

The effects of physical pretreatments including steaming, dry heating and a combination thereof (performed at different times) were evaluated on the content of resistant starch (RS), slowly digestible starch (SDS), and rapidly digestible starch (RDS), morphology, crystalline structure, and some other physicochemical properties of uncooked Iranian rice grains (Fajr cultivar). The grains were then subjected to cooking by various methods (i.e., boiling, rinsing, and steam-cooking) to investigate the effect of cooking on the nutritional properties obtained after applying physical pretreatments. Generally, reaction constant (k), hydrolysis index (HI), and estimated glycemic index (eGI) decreased after pretreatments. Physical pretreatments increased R1047/1022. Pretreated and cooked grains had significantly higher RS content (5–20%) than non-treated cooked samples. Morphology and crystalline structure were affected by pretreatments. Cooking by rinsing method is suggested for patients with type 2 diabetes mellitus because of lowering the HI (30%) and eGI (18%). Steam-cooking method is recommended for preparing a dietary rice meal due to the higher RS and SDS content. Pretreatment by steaming and cooking by boiling are suitable for people suffering from chewing problems. In conclusion, applying physical pretreatments and choosing appropriate cooking method can increase RS content, decrease eGI, and hence improve nutritional characteristics of rice grains.

The combined effect of oil-in-water emulsion soaking and modified pressure parboiling on starch digestibility of whole rice grains

The present work explores the enhancement strategy of resistant starch (RS) and slowly digestible starch (SDS) content in whole rice through oil-in-water emulsion (OIWE) soaking following modified pressure parboiling forming RS5 or lipid-amylose complex and RS3 or B-type crystals. Paddy was soaked for 8 h at 65 °C in OIWE prepared from 5 ml oil (coconut, sunflower, palm, and soybean oil) in 100 ml OIWE and emulsifier (Tween-20 or soy lecithin) through sonication. Soaked paddy was pressure parboiled (PP) and further treated with subsequent modified pressure-parboiling steps, i.e., pressure-parboiling-steam-refrigeration (PPR), pressure parboiling-refrigeration-microwave (PPRM), and pressure-parboiling-refrigeration-microwave-refrigeration (PPRMR). A stepwise increment in RS (significant) and SDS content was observed in all water-soaked samples than in the raw sample when exposed to PP and each step of modified pressure parboiling. All OIWE-soaked samples with different treatments showed an escalation in RS and SDS content than raw and water-soaked samples. Among all samples, the coconut oil-in-water emulsion (COIWE) soaked PPRMR treated sample (oil: Tween 20 and oil: soy lecithin = 1:1, average droplet sizes of 190.9 and 274.5 nm and ζ-potentials of −18.6 and −39.5 mV, respectively) exhibited the highest enhancement in RS level (12.93 ± 0.41 g/100 g and 10.75 ± 0.32 g/100 g for Tween-20 and soy lecithin stabilized COIWE).

Effect of the Pasta Making Process on Slowly Digestible Starch Content.

The rate at which starch is digested in the human intestine elicits different glycemic responses and reflects the glycemic index (GI) of foods. In vitro measurement of starch digestibility can reflect the GI of food. Differences in starch digestibility among four durum wheat pasta samples, couscous, and bread were evaluated to better describe the role of the pasta making process in affecting starch digestibility. Statistical differences in RDS (rapidly digestible starch), SDS (slowly digestible starch), and RS (resistant starch) of products were found (p < 0.05). As expected, pasta samples showed the highest value of SDS/av starch compared to couscous and bread. Fusilli and cavatelli samples presented the highest SDS/av starch ratio (55.80 ± 3.06% and 53.91 ± 3.50%, respectively), then came spaghetti 49.39 ± 2.83% and penne 45.93 ± 1.19%, while couscous presented the lowest value of SDS/av starch (2.64 ± 0.50%), followed by bread (11.78 ± 2.63%). Our study confirmed that the pasta making process efficiently mediates an increase in SDS/Av starch content, which has been specifically quantified above 40%, therefore strongly related to a lowered glycemic response in vivo. Our results strengthened the concept that pasta is a good source of SDS, which makes it useful for glycemic control.

Structural and in vitro starch digestion properties of starch-fatty acid nanocomplexes: effect of chain lengths and degree of unsaturation of fatty acids.

The structural and digestion properties of starch-lipid complexes are closely related to the properties of lipids. The chain length and degree of unsaturation of fatty acids (FAs), which can affect the structural and digestion properties of starch-lipid nanocomplexes, therefore need to be examined in detail to gain a better understanding of this. In this study, the effects of chain length (10-18 carbons) and degree of unsaturation (0-2) of FA on the structural and in vitro starch digestion properties of high amylose corn starch (HAS)-FA nanocomplexes were investigated, as was the correlation between their structural alterations and digestibility. This study showed that HAS-FA nanocomplexes with 10-carbon (38.55%) and 12-carbon (44.56%) FAs displayed high-resistant starch (RS)and slowly digestible starch (SDS) content, whereas those with 18-carbon FAs with two double bonds exhibited low RS + SDS content (23.41%). The complexing index, R1047/1022 , relative crystallinity, and enthalpy change in the HAS-FA nanocomplexes also increased with the reduction in the chain length (except for 10-carbon FA) and the degree of unsaturation of FAs, whereas the equilibrium hydrolysis percentage, kinetic constant and apparent amylose content showed an opposite trend. Chain length and degree of unsaturation of FAs affected the digestibility of HAS-FA nanocomplexes. The HAS-FA nanocomplexes with 12-carbon FAs displayed high RS + SDS content with higher degrees of molecular order at long-range and short-range levels. Results provided guidelines to regulate the digestibility of starch-fatty acid nanocomplexes by varying the FA structures. © 2022 Society of Chemical Industry.

Digestibility and structure changes of rice starch following co-fermentation of yeast and Lactobacillus strains

Rice is sometimes fermented with microorganisms to develop health-promoting foods, but the contribution of a short-term fermentation (a necessary step for fermented rice cake-preparation) to properties of rice starch is not resolved yet. The effects of microorganism fermentation with different amount of starter cultures on multi-scale structures and digestibility of rice starch were investigated. The amount of starter cultures significantly affected structures and digestibility of fermented starch. The fermentation with a lower amount of starter cultures induced starch degradation (corrosion of starch granules, reduction of lamellar orders and compactness, decrease in crystallinity, double helix, short ranger-ordered structures, and molar mass) and a slightly reassembly, which increased the content of slowly digestible starch (SDS). While, the fermentation produced more starch fractions with Mw between 0.60 × 107 g/mol and 1.50 × 107 g/mol as the amount of starter cultures increased, and these starch molecules tended to reassemble and form more ordered multi-scale structures including double helical and short range-ordered structures, starch lamellar orders and compactness, which elevated SDS content. The SDS content of fermented starchy foods could be improved via controlling starch reassembly and multi-scale ordered structures through modulating the amount of starter cultures during fermentation.

In vitro Digestibility Profiles of Different Types of Resistant Starch With Bioactive Guest Inhibitors

Abstract Objectives Retardation of starch digestion is an effective way of optimizing glycemic response. As the non-digestible portion of starch, resistant starch (RS) is associated with several beneficial effects such as regulating blood glucose level and improving gut health. Although all types of RS demonstrate such health benefits, different subtypes and structures may lead to variations in the digestibility profile. The aim of this study was to investigate and compare the in vitro digestibility of type 2 RS (RS2), type 3 RS (RS3), and novel type 5 RS (RS5) produced by starch inclusion complexes with ascorbyl palmitate (AP) and palmitic acid (PA) as potential inhibitors or guest compounds. Methods Two RS2 samples (high amylose maize starch, HAMS; potato starch, PS) in both raw and cooked forms, and RS3 samples produced by retrogradation of the two starches were tested for in vitro enzymatic digestion. AP and PA were either added during the digestion of RS2 and RS3 samples as potential inhibitors or processed to form inclusion complexes with starch prior to digestion as guest compounds of RS5. Starch digestibility profiles, represented by rapidly digestible starch (RDS), slowly digestible starch (SDS), total digestible starch (TDS), and RS contents, were determined. Results Cooking significantly increased the digestibility of RS2, while retrogradation (formation of RS3) inhibited the digestion by increasing the SDS and RS contents. The addition of AP significantly inhibited the in vitro digestion of RS2 (both raw and cooked HAMS and PS) and RS3 (retrograded HAMS and PS). The digestibility profile of RS5 produced by forming starch inclusion complexes with AP and PA was comparable to that of RS3, which exhibited higher SDS and RS contents as compared to cooked RS2. Conclusions AP as a bioactive guest compound could inhibit the in vitro digestion of raw and cooked RS2 and RS3. RS5 produced by forming starch inclusion complexes with AP and PA presented comparable digestibility with RS3, and higher SDS and RS contents as compared to cooked RS2. Since raw RS2 is not normally consumed in daily life, RS3 and RS5 could serve as better choices for daily consumption. In addition, adding certain bioactive food components could compensate for RS loss, suggesting a practical way of modulating glycemic response. Funding Sources University of Alabama Emerging Scholar Program and Faculty Start-up Fund.

Expression and characterization of 1,4-α-glucan branching enzyme from Microvirga sp. MC18 and its application in the preparation of slowly digestible starch

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.

Effect of Annealing on Structural, Physicochemical, and In Vitro Digestive Properties of Starch from Castanopsis sclerophylla

AbstractAnnealing is a hydrothermal treatment that changes the structural and functional properties of starches. This study investigates and compares the effects of one‐step annealing for 24 and 48 h, respectively, and two‐step annealing on the structural, physicochemical, and digestive properties of Castanopsis sclerophylla starch (CaS). Annealing has no effect on CaS morphology, crystalline pattern, and short‐range ordered structures. However, annealing decreases the swelling power, solubility, setback, and peak viscosity of CaS and increases its crystallinity and thermal stability. Post annealing, the rapidly digestible starch (RDS) of CaS decreases, the slowly digestible starch (SDS) increases while the resistant starch (RS) content of CaS remains unchanged. Comparing with One‐step annealing for 24 h, one‐step annealing for 48 h and two‐step annealing does not further change the RDS and SDS content of annealed CaS.

Effects of heat–moisture treatment conditions on the physicochemical properties and digestibility of field bean starch (Vicia faba var. minor)

In the presented study, starch of two cultivars of field bean was modified via the heat-moisture treatment (HMT) at various moisture contents (15 and 30%) and temperatures (100 and 120 °C) to determine HMT effect on its physicochemical properties and digestibility. Non-modified (NM) starches showed only slight variation in properties, with the tested varieties differing only in slowly digestible starch (SDS) and resistant starch (RS) content. The HMT was shown to decrease the swelling power and amylose leaching and higher phase transition temperatures and wider gelatinization temperature ranges in all modification conditions. These effects were caused by changes in the starch structure, as evidenced by the observed the decrease in relative crystallinity. The changes were the most pronounced in the starches treated at the higher moisture level. The HMT modification modified also starch digestibility. The total content of SDS and RS in non-gelatinized HMT starches modified at 15% moisture content was higher than that determined in the starch modified at 30% moisture content. In most gelatinized HMT starches, the SDS content decreased and that of RS did not change significantly compared to the native starch. Despite modified physicochemical properties, those starches still represent a good source of resistant starch.

Deep Dive Into the Effects of Food Processing on Limiting Starch Digestibility and Lowering the Glycemic Response.

During processing of cereal-based food products, starch undergoes dramatic changes. The objective of this work was to evaluate the impact of food processing on the starch digestibility profile of cereal-based foods using advanced imaging techniques, and to determine the effect of preserving starch in its native, slowly digestible form on its in vivo metabolic fate. Four different food products using different processing technologies were evaluated: extruded products, rusks, soft-baked cakes, and rotary-molded biscuits. Imaging techniques (X-ray diffraction, micro-X-ray microtomography, and electronic microscopy) were used to investigate changes in slowly digestible starch (SDS) structure that occurred during these different food processing technologies. For in vivo evaluation, International Standards for glycemic index (GI) methodology were applied on 12 healthy subjects. Rotary molding preserved starch in its intact form and resulted in the highest SDS content (28 g/100 g) and a significantly lower glycemic and insulinemic response, while the three other technologies resulted in SDS contents below 3 g/100 g. These low SDS values were due to greater disruption of the starch structure, which translated to a shift from a crystalline structure to an amorphous one. Modulation of postprandial glycemia, through starch digestibility modulation, is a meaningful target for the prevention of metabolic diseases.

Insights into the structural characteristics and in vitro starch digestibility on steamed rice bread as affected by the addition of okara

Starch structure and digestibility strongly depends on food composition during rice bread processing. This study investigates the effect of okara (0%, 7%, 14%, 21%) on the texture, in vitro starch digestibility, and multiscale structure (i.e. granule, crystallites, and short-range order) of steamed rice bread (SRB). Texture profile analysis results demonstrated that okara increased the elasticity and viscidity and reduced the hardness, cohesiveness, and chewiness of SRB. The addition of okara increased amylose content, slowly digestible starch (SDS), and resistant starch (RS) of SRB significantly, thereby reducing the predicted glycemic index (pGI) from 79.14 to 74.17–68.91. Meanwhile, SEM results showed that addition of 7% okara promoted the formation of the porous space starch–gel network structure in the SRB while 21% okara produced rougher surfaces and increased bread matrix density. XRD and FTIR revealed that suitable amounts of okara (<14%) assisted in starch arrangement while others (21%) reduced the ordered crystallization of starch. Results showed that the enhanced intermolecular hydrogen bonding between okara and water enhanced the viscosity and gas retention of SRB, thereby enabling the starch to retain more gas and form a loose starch gel structure spatial network. Furthermore, the addition of okara changed the multiscale structural and amylose contents when the SDS and RS contents are high and the pGI is low. As a result, the action sites of amylase can be shielded effectively to restrict the interaction of amylase with starch. Thus, this research suggests a potential approach in which rice complexed with okara can modify the texture and starch digestibility of SRB.

Impact of Extrusion Temperature on In Vitro Digestibility and Pasting Properties of Pea Flour.

Pea flour was extruded at 50, 70, and 90°C. The in vitro digestibility and characteristics of native and extruded pea flour were investigated. The in vitro starch digestibility (IVSD) and in vitro protein digestibility (IVPD) of the extruded pea flour were higher than those of the native pea flour and increased with increasing extrusion temperature from 50 to 90°C. The rapidly digestible starch increased to 28.34% at 90°C, the highest slowly digestible starch (SDS) content was 22.70% at 50°C, and resistant starch content decreased to 4.71% at 90°C. The IVPD increased from 80.94% relative to the native pea flour to 90.21% at 90°C. Improved swelling power enabled the extruded pea flour to exhibit better performance and higher breakdown viscosity and lower setback viscosity than the native pea flour demonstrated that extrusion reduced the thermal stability and retrogradation tendency. Increasing extrusion temperatures greatly reduced the relative crystallinity (based on X-ray diffraction analysis) from 32.69% relative to the native pea flour to 9.76% at 90°C. Extrusion treatment also reduced β-sheet content (based on Fourier transform infrared spectroscopy analysis) from 36.40% relative to the native pea flour to 31.79% at 90°C. IVPD and IVSD improved, and the SDS content increased at 50°C and 70°C, thereby indicating that extruded pea flour can be applied to healthy food products.

The Influence of Starch Modification with Amylosucrase Treatment on Morphological Features

Amylosucrase (AS) is a starch-modifying enzyme from Neisseria polysaccharea used to produce low-glycemic starches such as slowly digestible starch (SDS) and resistant starch (RS). The morphology of native, control, and AS-modified waxy corn starches (230 and 460 U) was examined using a particle size analyzer and field-emission scanning electron microscopy (FE-SEM). AS modification of the starch elongated the glucose and resulted in higher SDS and RS contents. The mean particle sizes of the control, 230 U-AS-, and 460 U-AS-treated starches were 56.6 µm, 128.0 µm, and 176.5 μm, respectively. The surface of the 460 U-AS-treated starch was entirely porous and coral-like, while the 230 U-AS-treated starch had a partial dense and flat surface which did not react with AS. FE-SEM of the granule cross section confirmed that the center contained a dense and flat region without any evidence of AS reaction to either of the AS-treated starches. It was assumed that the particle size and porous and sponge-like particle features might be related to the SDS and RS fractions.

Changes in physicochemical, nutritional characteristics and ATR-FTIR molecular interactions of cereal grains during germination.

The cereal grains such as wheat, barley, sorghum, millets were evaluated before and after germination (24h, 48h and 72h) and compared for their proximate composition, antioxidant activity, total phenolic content, total flavonoid content, pasting properties, in vitro starch digestibility and FTIR spectroscopy. Germination inversely affected the protein, fat, and ash content of different cereal grains. The germinated flours have less water content and higher oil absorption capacities along with reduced starch content. The contents of rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) in the ungerminated cereal flours ranged from 20.7 to 32.1%, 26.9 to 38.0% and 6.2 to 17.6% respectively but after germination of 72h, the RDS content increased from 26.5 to 36.2% while SDS and RS content decreased from 26.1% (sorghum) to 16% (barley) and 14.7% (barley) to 4.6% (wheat) respectively. The drought-tolerant crops (sorghum, millets and barley) are potential sources of antioxidants and phenolic content and yielded lower hydrolysis index and estimated glycaemic index upon germination. The highest section of antiparallal β-sheet, α-helix and β-turns were found in wheat flour followed by sorghum flour and their proportion decreased with continuous germination. The continuous reduction of viscosity was evaluated with the progress in germination. Overall, germination is a way to get health-promoting compounds from less utilizing cereal such as millets, sorghum and barley and enhance their uses to nourish the huge population with the aim to fulfill their nutritional requirements.

Effects of fatty acids with various chain lengths and degrees of unsaturation on the structure, physicochemical properties and digestibility of maize starch-fatty acid complexes

In this study, we investigated the effects of chain length and degree of unsaturation of fatty acid (FA) on the structure, physicochemical properties, and in vitro digestibility of maize starch (MS)–FA complexes. Differential scanning calorimetry, X-ray diffraction, and Raman spectroscopy revealed that crystalline structure with V-type was formed between MS and FA. Nuclear magnetic resonance spectroscopy confirmed that the complexes with various FA structures displayed different V-type polymorphs. The thermal stability of the complexes with 14-carbon and 16-carbon FAs was better than that of other complexes. The complexes with 12-carbon (21.77%) and 14-carbon (26.31%) FAs displayed high resistant starch (RS) content, whereas those with 10-carbon FAs exhibited high slowly digestible starch (SDS) content (28.99%). Additionally, the FAs with a chain length of 10–14 carbons produced more ordered structures and showed stronger intermolecular interactions with MS than other FAs. For the 18-carbon FAs, the complexes with unsaturated FAs displayed higher RS and SDS content than those with saturated FAs. Moreover, the unsaturated FAs showed stronger intermolecular interactions with MS than the saturated FAs. These results indicated that FA structures significantly affected the structures of complexes, further affecting their physicochemical and digestive properties.

Inhibition of Starch Digestion by Dallic Acid and Alkyl Gallates

Abstract Objectives Retardation of starch digestion is an effective way of optimizing glycemic response. Certain bioactive food components inhibit starch digestion by binding with starch digestive enzymes or starch molecules in the digestive tract. Inclusion complexation between starch and guest compounds is a specific non-covalent binding mode and may contribute to a lower digestibility of starch. The aim of this study was to examine the inhibitory effects of alkyl gallates on in vitro starch digestion and the mechanism of inhibition. Methods Raw and cooked high amylose maize starch (HAMS) and potato starch (PS) were tested for in vitro enzymatic digestion. Gallic acid (GA) and alkyl gallates, including butyl (BG), octyl (OG), dodecyl (DG), hexadecyl (HG), and octadecyl (SG) gallates, were either added during digestion or processed to form inclusion complexes with starch prior to digestion. Starch digestibility profiles, represented by rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) contents, were determined. Results GA and alkyl gallates significantly increased (P &amp;lt; 0.05) RS content in raw starches. Cooked starches had significantly lower RS contents than raw starches. GA and BG increased RS content in cooked HAMS, while all compounds except for SG increased RS content in cooked PS. DG and HG caused a significant increase in SDS contents in cooked HAMS but not in raw starches and cooked PS. Significant increases in SDS and RS contents were seen in HAMS inclusion complexes with DG and HG, compared with uncomplexed starch. Conclusions The bioactive food components tested could all inhibit starch digestion either by inhibiting the enzymes or by forming starch inclusion complex. As alkyl chain length increased, their inhibition on enzymatic activity decreased, but their ability to bind starch increased. While cooking makes starch more digestible, adding certain bioactive food components could compensate for RS loss, suggesting a practical way of modulating glycemic response. Funding Sources USDA National Institute for Food and Agriculture.