Formation Of Resistant Starch Research Articles

Nutritional properties of starch in buckwheat noodles.

Buckwheat noodles were studied to identify the possibility of reduced starch hydrolysis rate and glucose release after the ingestion of buckwheat meals, in comparison to the wheat-based meals. The rate of starch hydrolysis and the resistant starch (RS) formation in boiled buckwheat noodles (BWN), boiled wheat noodles (WN), boiled buckwheat groats (BWG), and white wheat bread (WB) were evaluated in vitro. The highest content of RS (total starch basis) was found in boiled BWG (6%), compared with the BWN (3.4%), WN (2.1%), and WB (0.8%). The rate of in vitro amylolysis was significantly reduced (p<0.05) in both studied buckwheat products in comparison to the reference WB. The calculated hydrolysis index (HI) was lower in BWN (61) in comparison to WN (71), but higher in comparison to boiled BWG (50). It is confirmed that BWN have some potential in diets designed in accordance with the dietary recommendations for diabetic patients and for healthy subjects.

Resistant Starch Derived from Extruded Corn Starch and Guar Gum as Affected by Acid and Surfactants: Structural Characterization

Corn starches with and without guar gum [10% (w/w)] and 2% (w/w) of diacetyl tartaric acid ester of monoglyceride, sodium stearoyl-2-lactylate or citric acid, respectively, were extrusion-cooked in a twin-screw extruder at 18% moisture, 150 °C and 180 rpm screw speed. The content of resistant starch was determined by sequential enzymatic digestion. The formation of resistant starch in extruded corn starch was strongly affected by the addition of gum and the different food additives. X-ray diffraction of the extruded starches gave a V diffraction pattern indicating the effect of extrusion cooking and amylose-lipid complexes. Enzymatic digestion did not affect the V-structure, which could apparently be attributed to extrusion cooking. Similarly, differential scanning calorimetric thermograms indicated that all isolated resistant starches exhibited endothermic transitions between 71—178 °C signifying a complex formation between amylose and the emulsifiers and possibly the melting of amylose crystallites in the resistant starch. Purification of the isolated resistant starches by size exclusion-high performance liquid chromatography showed a dependence of molecular weight on the added additives. Results of differential scanning calorimetry and X-ray diffraction suggest that amylose-lipid complexes could also be involved in the formation of resistant starch in extruded cornstarch.

Effect of irradiation, with and without cooking of maize and kidney bean flours, on porridge viscosity and in vitro starch digestibility

AbstractAfrican traditional weaning foods are usually prepared from starchy flours at a total solids content of 50–100 g l−1, giving a viscosity of 1000–3000 cP which is consumable by infants. These porridges have very low energy and nutrient densities. Processing to reduce the porridge viscosity and improve the energy and nutrient density may help in solving this problem. Maize, kidney bean and their 70:30 composite flours were irradiated at 0–10 kGy at room temperature. Irradiation greatly reduced the viscosity of porridges, probably by starch depolymerisation. Irradiation improved the starch digestibility of raw bean flours, possibly either by inhibiting α‐amylase inhibitors or by weakening the thick cell walls that enclose the starch granules, thus improving accessibility to enzymes. However, in raw maize, cooked maize and cooked bean flours there was maximum starch digestibility at a dose of 2.5 kGy, followed by small but significant decreases in starch digestibility at higher doses, more so in maize than in bean flours. The decrease in digestibility could be due to the formation of inhibitors of amylolytic enzymes (Maillard reactions products) or to the formation of resistant starch. Irradiation doses required to increase the total solids content of traditional maize‐ and/or bean‐based weaning porridges to at least 200 g l−1 do not compromise starch digestibility significantly.© 2001 Society of Chemical Industry

Resistant Starch Formation in Grain Distillery Mashes*

Research based on wort separation problems in a grain distillery indicated that prolonged holding of cooked maize caused the production of significant quantities of resistant starch, which was mainly present in the fine mash solids. Mashes containing resistant starches were difficult to filter and this filtration difficulty did not reflect differences in β-glucan content or clear wort viscosities. The conversion efficiency and fermentability of the worts from slow-filtered mashes were reduced. The resistant starch material was associated with a white residue, which was soluble in dilute alkali but not in hot water, and stained positively for starch in alkaline solution but not in water.

Nutritional properties of starch in buckwheat products: studies in vitro and in vivo.

The nutritional characteristics of buckwheat starch were studied to identify the possibility for reduced postmeal metabolic responses to various buckwheat products. The in vitro rate of starch hydrolysis and resistant starch (RS) formation in boiled buckwheat groats and in a series of breads, baked with 30-70% of buckwheat flour (BWF) or groats (BWG), respectively, were evaluated in vitro. In parallel, postprandial glucose and insulin responses and also the satiety score to BWG and wheat bread with 50% BWG as compared with the reference white wheat bread (WWB) were studied in healthy humans. The highest concentration of RS was found in boiled BWG (6% total starch basis). The RS level in bread products based on different proportions of BWF or BWG (30-70%) varied from 0.9 to 4.4%. The rate of in vitro amylolysis was significantly lower (P < 0.05) in all buckwheat products in comparison with the reference WWB. The calculated hydrolysis indices (HI) were lowest in boiled BWG (HI = 50) and in bread with 70% BWG (HI = 54). Consumption of boiled BWG or bread based on wheat flour and 50% BWG induced significantly lower postprandial blood glucose and insulin responses compared with the WWB. The calculated glycemic and insulinemic indices (GI and II) for boiled BWG were 61 and 53 and for the buckwheat bread, 66 and 74, respectively. The highest satiety score was found with boiled BWG. It is concluded that buckwheat has potential use in the design of foods with lower GI properties.

Inhibition of Enzymic Digestion of Amylose by Free Fatty Acids In Vitro Contributes to Resistant Starch Formation

The effect of lipids on the enzymic breakdown of starch was investigated using an in vitro assay system. Mixtures of potato amylose, amylopectin and starch and various lipids were incubated at 37 degrees C for 10 min and subjected to digestion by alpha-amylase (EC 3.2.1.1) and amyloglucosidase (EC 3.2.1.33). Lauric, myristic, palmitic and oleic acids and lysolecithin inhibited enzymic hydrolysis of amylose by approximately 35% (P < 0.05). Stearic acid and cholesterol had no effect on the enzymic breakdown of amylose. Retrograded amylose was hydrolyzed less readily (P < 0.05) than solubilized amylose, but the breakdown was not further inhibited in the presence of lauric acid. Fatty acids had no effect on the enzymic hydrolysis of amylopectin, whereas inhibition by fatty acids of the breakdown of whole starch was consistent with only the amylose fraction being affected. The possibility that interactions between starch and fatty acids in the digestive tract could contribute to the formation of resistant starch is considered.

Studies on α-amylase degradation of retrograded starch gels from waxy maize and high-amylopectin potato

Gelatinized starch gels of waxy maize and high-amylopectin potato were subjected to different time–temperature conditions, aiming at producing extensive amounts of retrograded amylopectin. The purpose was to investigate the impact of amylopectin retrogradation on the resistant starch formation and on the rate of starch digestion with porcine pancreatic α-amylase. Dried non-cycled gelatinized starch gels were used for comparison. Although differential scanning calorimetry measurements indicated higher amounts of retrograded material in the dried temperature-cycled gels no enzyme resistant starch was detected in any of these samples. However, all cycled starch gels were less-readily degraded by the enzyme than the non-cycled gels. The chain length distribution in the α-amylolysates was studied by high performance anion exchange chromatography after debranching with isoamylase. The main products of hydrolysis were low molecular weight carbohydrates with a degree of polymerization of 1–9 and various branched dextrins. The chain distribution was uniform in the hydrolysates at the different stages of hydrolysis and independent of storage conditions, indicating that the mode of enzyme action remained unaffected by retrogradation. The waxy maize and high-amylopectin potato starches responded similarly to temperature cycling. It was concluded that temperature cycling resulted in a slower hydrolysis of the amylopectin, a phenomena that could be exploited when developing starchy foods with improved nutritional characteristics.

Resistant starch from differently processed rice and ragi (finger millet)

Resistant starch (RS) formed during parboiling, expanding, popping, flaking, roller drying, extrusion cooking, malting and autoclaving of rice and ragi was determined. The processing conditions were chosen to represent the limits that are being used commercially. RS formation was more pronounced in autoclaving and a drastic increase (∼fivefold) in its content was observed during repeated autoclaving (heating and cooling) was observed. Though processed ragi samples contained more nitrogen, protein and dietary fibre, the RS content was very low compared to rice. Hot paste viscosity studies showed the extruded and malted samples to have low peak and set-back viscosities. Determination of the percentage of starch gelatinization revealed that powdered samples showed 100% gelatinization at higher temperatures whereas malted and extruded samples showed the same at low temperatures.

Assessment of some parameters involved in the gelatinization and retrogration of starch

Factors influencing the formation of resistant starch (RS) during gelatinization and retrogradation were studied in starches and flours from cereals (wheat, corn, rice) and potato. RS obtained using a high-pressure autoclave system varied between 3.94 and 21.21% (rice and potato starches, respectively) similar to the values obtained after gelatinization in a boiling water bath. Except for rice, RS was higher in pure starches than in flours. Stirring during gelatinization yielded more homogeneous products than non-stirred samples. Apparently, gelatinization was unaffected by pH values between 3.5 and 10.5. To obtain optimum RS yields during retrogradation, it was necessary to cool down starch gels prior to freezing, followed by thawing at room temperature and drying at 60°C. These conditions ensure good yields in the formation of RS with potential industrial applications. ©

Resistant starch from processed cereals: the influence of amylopectin and non-carbohydrate constituents in its formation

The effect of removal of protein and lipids on the resistant starch (RS) content of processed rice and ragi has been studied. The percent recovery of RS increased significantly (over 2–3-fold) after defatting and autoclaving. However, deproteinization did not show any major difference. Prolonged storage of gelatinized starch suspensions showed considerably more undigested mass even after extended α-amylolysis, probably due to the involvement of long unbranched chains of amylopectin in the formation of RS. Thermal characteristics of these processed flours/starches showed variable enthalpy values. X-ray diffraction data revealed both B- and V-type diffraction patterns for the isolated RS.

Influence of Botanical Source and Processing on Formation of Resistant Starch Type III

ABSTRACTInfluence of botanical source and gelatinization procedure (autoclaving or boiling) on resistant starch (RS) formation was investigated in starches from wheat, corn, rice, and potato. RS yields did not vary within the same sample but differed among samples with different starch botanical sources. Differences also existed in RS contents in native and retrograded starches. Slight or minor variations in RS values were found after both gelatinization procedures, although no clear pattern was found in the behavior of samples based on gelatinization procedure. The degree of polymerization (DP) of retrograded samples was assigned using high‐performance anion exchange chromatography with pulsed amperometric detector (average DP 50–60), with no differences between autoclaved and boiled samples.

Effect of Various Processing Methods on the in Vitro Starch Digestibility and Resistant Starch Content of Indian Pulses

The effect of different processing treatments on the in vitro starch digestion rate and resistant starch (RS) formation in two little-known Indian legumes (moth bean and horse gram) as compared with a pulse widely consumed in Asian countries (black gram) was studied. Samples were cooked until edible without previous treatment, after overnight soaking in water or in a 0.02% sodium bicarbonate solution, and after sprouting. Cooked samples were analyzed for their RS content immediately after cooking or after storing for 24 h at 4 °C. The in vitro starch digestion rate was also measured in the freshly cooked (FC) legumes, and the hydrolysis index (HI) and glycemic index (GI) were calculated. RS in processed samples varied between 2.7 and 7.9 g kg-1 of dry matter, the highest values corresponding to the stored legumes. Sprouting and direct cooking resulted in the lowest RS content in FC and stored legumes, respectively. Soaking significantly improved in vitro starch digestibility in the little-known pulses but not in black gram. Sprouting yielded the highest HI and GI. Keywords: Little-known legumes; processing; resistant starch; starch digestibility

Effects of Amylose/Amylopectin Ratio and Baking Conditions on Resistant Starch Formation and Glycaemic Indices

The possible improvement of the nutritional properties of starch in barley flour-based bread by using barley genotypes varying in amylose content (3–44%) was evaluated. Breads were made from 70% whole-meal barley flour and 30% white wheat flour. Test breads were baked from waxy barley (WB), ordinary barley (OB), ordinary Glacier barley (OGB) and high-amylose barley (HAB). Each bread was baked either at conventional baking conditions (45 min, 200 °C) or at pumpernickel conditions (20 h, 120 °C). A white wheat bread (WWB) was used as reference. The resistant starch (RS) content and rate of starch hydrolysis were measuredin vitro. The glycaemic index (GI) and the insulinaemic index (II) of the high-amylose breads were determined in healthy subjects. The amount of RS (total starch basis) varied from <1% (WB) to approximately 4% (HAB) in conventionally baked bread, and from about 2% to 10% in the corresponding long-time/low-temperature baked products. The long-time/low-temperature baked HAB displayed a significantly lower rate of starch hydrolysisin vitrocompared with WWB and reduced the incremental blood-glucose response in healthy subjects (GI=71). In contrast, the GI of the conventionally baked HAB was similar to that for WWB. It is concluded that a barley flour-based bread of low GI and high RS content can be obtained by choosing high-amylose barley and appropriate baking conditions.

OCORRÊNCIA E CARACTERIZAÇÃO DO AMIDO RESISTENTE EM AMIDOS DE MILHO E DE BANANA

In this work the occurrence of resistant starch (RS) in normal corn and banana (naturally resistant) starches was studied and also the effects of conditioning moisture, storage temperature and time on the formation of RS in normal corn starch. The physico-chemical characteristics of the RS from corn and banana were also studied, including the molecular structure. The proximate composition data showed that the percentage of RS is not related to the chemical composition of the granule. Banana starch showed granules with a certain polyformism, and a B x-ray diffraction pattern. The dextrins from this starch showed a linear fraction with DP 34 resistant to sequential action of b-amylase and/or pulullonase. The pasting characteristics indicated that the high RS content observed in this starch, could not be explained by the physical structure which maintains the granule. The normal corn starch showed polyhedral shapes. Exclusion gel chromatography of the residues obtained after b- amylase and/or pulullonase hydrolysis, did not show a fraction with DP 34, although the pasting properties indicated a higher granule cohesivity than that of the banana starch. The hydrothermal treatment almost triplicated the RS content (7.15%) of the corn starch, because of the formation of more cohesive structures inside the granule. The retrograded corn starch, with 7.15% RS, was constituted of porous fragments and a C type diffraction pattern. On the other hand, the non significance of storage time on the formation of RS in conjunction with the absence of a fraction with DP 34, suggested the participation of amylose in this resistant structure.

Formation of Resistant Starch by a Twin‐Screw Extruder

ABSTRACTThe objective of this study was to evaluate the potential to increase the level of resistant starch (RS) in extruded products by optimizing extruder conditions. Three experiments were conducted as randomized complete block designs with two replicates. In the first experiment, corn starch, wheat starch, and potato starch were added at a level of 30% (w/w) to degerminated yellow corn meal to investigate the influence of starch type. In the second experiment, citric acid (CA) monohydrate was added to corn meal at levels of 0, 2.5, 5, and 7.5% (w/w). The third experiment was a full‐factorial arrangement to evaluate the effect of high‐amylose corn starch (HACS) level (0, 15, 30%, w/w) and CA level (0, 5, 7.5%, w/w) at two screw speeds (200 and 300 rpm). In the first experiment, the means for RS plus dietary fiber for the different starch formulations ranged from 1.27 to 2.28%. In experiment 2, adding CA increased RS plus dietary fiber content to a maximum of 5.23% at 7.5% CA. In the third experiment, the means for RS plus dietary fiber ranged from a low of 1.75% for 100% corn meal at 300 rpm to 14.38% for 7.5% CA and 30% HACS at 200 rpm. The results indicated a highly significant positive relationship between CA and RS formation and the same for amylose content. The RS formation had a negative relationship with screw speed, but the influence of screw speed was small when compared with that of CA and HACS.

An approach to the influence of nutrients and other food constituents on resistant starch formation

The influence of nutrients and other food constituents, such as dietary fibre components, catechin and phytic acid, on resistant starch (RS) formation was systematically investigated. This investigation was carried out under standardized gelatinization conditions by using a high pressure autoclave (HPA). Except for insoluble dietary fibre constituents (cellulose and lignin), all the tested food ingredients reduced the formation of RS. Calcium ions, potassium ions and catechin showed the highest reduction of RS formation, while the nutrients studied (albumin, olive oil and sucrose) as well as phytic acid affected it to a lesser extent. These results were not significantly changed by varying amounts of the studied dietary components.

Tecnología del almidón resistente / Technology of resistant starch

In recent years the discovery of the starch fraction called resistant starch (RS) has lead to numerous investigations. The nature of this fraction is very heterogeneous, and it comprises different types of resistant starches. From a technological point of view, RS type III or retrograded starch is the most important fraction. This resistant starch is formed after heating and cooling processes which therefore may occur in numerous fresh foods and foodstuffs. This brief review describes the gela tinization and retrogradation, which occur during heating and cooling, involved in the formation of resistant starch. The influence on RS formation of technological processes used in the manu facture of cereals has been studied as well as the influence of certain treatments used in legumes. In addition, the interactions between starch and nutrients such as proteins, lipids and sugars have also been studied. Recently, a high pressure autoclave has been used in a gelatinization system, which allows a better technological control and an increase in RS yields in comparison to conven tional systems.

Content of dietary fiber in foods and its physiological effects

An increase in dietary fiber consumption has been recommended by the public health authorities. In this review the definition of dietary fiber and analytical methods used for its measurement are discussed. Furthermore, effects of processing on dietary fiber—especially the formation of resistant starch, the role of dietary fiber in health and disease, and intakes in different countries—are discussed.

Resistant starch--an update on its physiological effects.

Resistant starch (RS) has emerged as one of the main substrates for colonic fermentation, together with other undigestible polysaccharides and oligosaccharides. There are indications that RS may be a good source of butyrate, and that the rate and site of fermentation can be varied and optimized. This makes RS potentially important for colonic health, and production of food products containing RS challenging. The present RS content in most Western diets is probably low, but can be increased by foods high in RS. The physiological effects of RS are reviewed, as well as the formation of RS in foods and its analysis.

Resistant starch formation in bread as influenced by choice of ingredients or baking conditions

The formation of resistant starch (RS) in bread products was evaluated in vitro in relation to the processing conditions. The impact of the particular baking conditions applied to pumpernickel bread was investigated as well as the presence of malt and sourdough acids, commonly present in such bread. Also studied was the potential effect of including wholemeal barley from a high-amylose genotype. In some bread, the rate of hydrolysis of the potentially available starch fraction was evaluated by an in vitro procedure. A low-temperature, long-time baked product (20 h at 120 °C) contained significantly higher amounts of RS (5.4%, starch basis) than a corresponding ordinary baked bread (40min at 200 °C) (3.0%, starch basis). Addition of lactic acid increased RS recovery further (6.6% starch basis), whereas malt had no impact on RS yield. The highest level of RS was noted in a long-time baked bread based on high-amylose barley flour (7.7%, starch basis). In contrast to all other products, this bread also displayed a lowered rate of amylolysis of the non-RS fraction (hydrolysis rate index = 68). It is concluded that exchanging ordinary baking conditions for pumpernickel baking, particularly in the presence of certain organic acids, may substantially increase the RS content.