Digestibility Of Corn Starch Research Articles

One step purification and characterization of an extracellular α-amylase from marine Vibrio sp.

An α-amylase was purified from marine Vibrio sp. using starch affinity method with molecular mass of 52.480 kDa. This amylase showed maximum activity at 55–60 °C and pH 6.5 and retain 85% of maximal activity after 30 min preincubation at 65 °C. The enzyme was inhibited by ethylenediaminetetra-acetate (EDTA) and [ethylenebis(oxonitrilo)]tetra-acetate (EGTA) while divalent metal ions, such as Fe 2+, Mn 2+, Co 2+, Ca 2+, Mg 2 and Cu 2+ could restored near 25–55% of maximal activity suggesting that the metal ions need for the enzyme activity. Digestion of corn-starch by the enzyme showed random cleavage with various sizes of products, indicating endo action of the enzyme. Chemical modification suggested involvement of Lys, Trp, Asp/Glu and His in the enzyme activity. The starch affinity method used here showed high yield purified amylase with very low experimental cost.

The Effect of Heating at Subgelatinization Temperatures on Enzymatic Digestibility of Corn Starch

The effect of heating at 50 and 55°C on enzymatic digestibility of corn starch was investigated using flours from two corn hybrids (Furio and CMS 8806) prepared by dry- and wet-milling processes. Results obtained show that the enzyme-digestible starch percentage, in all cases, increases with heating time due to changes in the internal structure of the starch granules. The flours from dry milling have an enzyme-digestible starch percentage higher than that observed in wet milled flours with high moisture content.

A Twelve‐Hour In Vitro Procedure for Sorghum Grain Feed Quality Assessment

Improved methods for assessing cereal crop feed value are a prerequisite for the genetic improvement of sorghum [Sorghum bicolor (L.) Moench] feed value. Rate of starch digestion is now commonly believed to be the limiting factor in sorghum utilization by cattle (Bos taurus). However, techniques to assess this trait are not useful to sorghum breeders because of high labor inputs, lab error associated with starch measurement, and need for high numbers of replications. The objective of this study was to develop a simple technique capable of identifying differences in digestion between sorghum and corn (Zea mays L.) and detecting differences among sorghum genotypes. In vitro starch and dry matter digestion were measured on sorghum and corn lab standards at 0, 6, 12, 18, 24, 30, and 40 h. Maximum differentiation between corn and sorghum dry matter digestion (345 vs. 253 g kg−1) and starch digestion (403 vs. 301 g kg−1) occurred at 12 h, and dry matter and starch digestion were highly correlated (r = 0.99). Differences among five sorghum lines were significant for 12‐h dry matter digestion and ranged from 229 to 272 g kg−1. This procedure provides a precise and rapid technique that can be used by feed grain breeders to evaluate modifications in grain digestion parameters.

Expression and functional analysis of a hyperglycosylated glucoamylase in a parental host, Aspergillus awamori var. kawachi.

A modified glucoamylase gene (glaA) with an extra Thr- and Ser-rich Gp-I domain (T. Semimaru, M. Goto, K. Furukawa, and S. Hayashida, Appl. Environ. Microbiol. 61:2885-2890, 1995) was introduced into a mutant parental host, Aspergillus awamori var. kawachi, in which the original glaA gene had been completely deleted and replaced with the hygromycin phosphotransferase gene. The modified glaA was successfully expressed and secreted. The modified glucoamylase possessed higher digestibility of raw corn starch and higher stabilities in response to heat and extreme pH.

The Effect of Inclusion Level and Time on Digestibility of Starch for Common Carp ( Cyprinus carpio, Cyprinidae)

The effect of the level of inclusion and time on the digestibility of cornstarch for common carp (Cyprinus carpio, Cyprinidae) was determined. Raw cornstarch was included into a casein-based reference diet at four levels of inclusion (IO, 20, 30 and 40%) and digestibility coefficients calculated over two time points (days 6-10 and days 13-17). Starch digestibility was significantly affected by the level of inclusion, being higher at the 30% (90.4%) and 40% (94.2%) inclusion levels than at the 10% (77 .3%) inclusion level. Time had no significant effect on starch digestibility.

Effect of body weight and feed composition on the contribution of hindgut to digestion of energy and nutrients in pigs

The contribution of hindgut to digestion of energy and nutrients was measured at three body weights (BW) or stages of growth (stage 1: 45 kg; stage 2: 100 kg and stage 3: 150 kg) as the difference between fecal digestibility values measured at the three stages and ileal digestibility values estimated with 45 kg BW ileo-rectal anastomized (IRA) pigs. Six diets were tested. Composition of diets allowed calculation (by the difference method) of ileal and hindgut digestion of corn starch, sucrose, rapeseed oil and a mixture of fibrous ingredients (so-called “fibre”). Fecal digestibility of energy and nutrients was improved when BW was increased with higher values in intact pigs at the three stages (except for ether extract) than in IRA pigs. As a consequence, the contribution of hindgut to energy supply amounted to 15, 17 and 18% at stages 1, 2 and 3, respectively. This contribution varied with diet characteristics and ranged from about 11% in high-starch or high-sugars diets to 30% in the high-fibre diet. A major fraction of dietary crude protein (90%) and ether extract (100%) was digested before the end of the ileum while cell-wall fractions were predominantly degraded in the hindgut (70% for NDF). Hindgut digestibility of energy and NDF entering the hindgut averaged 48% and increased ( P<0.01) from stage 1 to stage 3. Accordingly, almost 100% of energy of corn starch or sucrose were digested before the end of the ileum. A small proportion of rapeseed oil energy (about 10%) was apparently degraded in the hindgut. A negligible fraction of energy of “fibre” (5%) was digested before the end of the ileum. Results demonstrate that methane production in pigs is not a reliable predictor of the fermentation rate in the digestive tract.

Raw Starch Digestion by α‐Amylase and Glucoamylase from Chalara paradoxa

AbstractGlucoamylase and α‐amylase of Chalara paradoxa were separated by hydrophobic column chromatography using butyl‐Toyopearl 650M. The α‐amylase showed the highest activity at pH 5.5 and 45°C, and was stable in the pH range of 5.5–6.5 and at temperatures lower than 40°C. The glucoamylase showed the highest activity at pH 5.0 and 45°C, and was stable in the pH range of 4.0–7.5 and at temperatures lower than 45°C. The molecular mass of the α‐amylase and glucoamylase estimated by SDS polyacrylamide gel electrophoresis was 80,000 and 68,000, respectively. Both glucoamylase and α‐amylase could digest more effectively raw rice starch and raw corn starch than raw sago starch and raw potato starch. 2% raw rice starch in 10 ml solution was digested by more than 90% by 100 units of each amylase. When these amylases were used combined, raw corn starch was more effectively digested than they were used singly. This cooperative action in raw corn starch digestion was also observed when. C. paradoxa α‐amylase and R. niveus glucoamylase were combined.

Change in Digestibility of Gamma‐Irradiated Starch by Low Temperature Cooking

AbstractCombination effect of irradiation and low temperature cooking on starch digestibility has been investigated as a basic research for application of radiosterilization on starch fermentation. The digestion of corn starch by glucoamylase after cooking at low temperature was enhanced by γ‐irradiation and the required cooking temperature was decreased from 75‐80°C to 65°C by 25 kGy. Gelatinization of starches except tapioca starch was enhanced by irradiation and it corresponds to the digestibility. The digestibility of potato starch which has a high viscosity was especially enhanced at low temperature cooking because the viscosity was markedly decreased by irradiation. These results show that the irradiation of starches is useful not only for the sterilization of fermentation broth but also for the enhancement of digestion.

Digestion and Absorption of Energy Substrates in the Lactating Cow

Manipulation of diet composition and meal frequency can produce different patterns of energy utilization from the same amount of digestible energy in the lactating cow. Estimates of the principal products of energy digestion in lactating cows are reviewed to explain these differences.Products of energy digestion can be estimated by measuring digesta flow at points along the digestive tract, rates of product formation by isotope dilution techniques, and nutrient uptake into the portal system. All of these techniques are difficult and expensive for lactating cows, and there are serious discrepancies among published values.Measurements of digesta flow indicate that 55 to 75% of energy digestion occurs in the rumen. The proportion is lower when concentrates are based on corn rather than on barley because of the lower digestibility of corn starch in the rumen. Estimates of volatile fatty acid production by isotope dilution techniques vary widely and, in some cases, are very different from estimates based on the extent of rumen fermentation obtained by measurements of digesta flow. With corn-based concentrates, there is a net increase in glucose supply to the portal vein from the gastrointestinal tract, but with barley-based concentrates the uptake of glucose from the gut is insufficient to meet the demands of the portal-drained viscera. A net decrease in glucose supply to the portal vein results.Based on the literature reviewed, uptake of nutrients from different diet types is estimated and related to energy utilization for milk production. It is suggested that calculation of mean daily supplies of individual nutrients is insufficient and that under some circumstances it is necessary to estimate diurnal fluctuation in supplies to understand the complex relationships among diet, nutrient supply, hormones, and milk production.

Multiplicity of Glucoamylase of Aspergillus oryzae Part 2. Enzymatic and Physicochemical Properties of Three Forms of Glucoamylase

AbstractThree forms of glucoamylase of Aspergillus oryzae had optimum pH range between 4.5 to 5.0 at 40°C and optimum temperature range between 40 and 60°C. They were most stable at pH range between 4.0 and 7.0 and temperatures up to 40°C. The molecular weights were 76.000, 38.000 and 38.000, respectively. Hydrolysis activities of the three glucoamylases on different substrates were studied. They differed in their rate of attack on many substrates. Glucoamylase I had strong debranching activity and was highly active in raw corn starch digestion. Glucoamylase II and III had weak debranching activities and could hardly digest raw starch.

Pullulanase Responsible for Digesting Raw Starch

AbstractIn a previous publication (Stärke 27 [1975], 123) the fractionation of glucoamylase from Rhizopus sp. into two fractions, glucoamylase I and glucoamylase II, was reported. Referring to the interaction of these two fractions with pullulanase the following observations were made: Pullulanase accelerated the raw waxy corn starch digestion by glucoamylase I of Rhizopus sp. Glucoamylase II was less active on the raw starch digestion than glucoamylase I, and pullulanase could not accelerate the raw waxy corn starch digestion by glucoamylase II. Intracellular and extracellular pullulanases had the same acclerating activity on the raw starch digestion by glucoamylase I or II. Pullulanase had a less acclerating activity on the raw non waxy corn starch digestion than raw waxy corn starch digestion. From this fact, it was suggested that the amylose in raw non waxy corn starch may hinder the raw starch digestion by glucoamylase.

Multiple Forms of Glucoamylase of Rhizopus Species

AbstractThe glucoamylase system of Rhizopus sp. was fractionated into two kinds of glucoamylase by using the corn starch adsorption technique supplemented by CM‐cellulose chromatography. One of these fractions, referred to as glucoamylase I, has a strong debranching activity and is highly active in raw starch digestion.The raw waxy corn starch digestion by glucoamylase I was accelerated by adding a‐amylase from Rhizopus sp. or from Aspergillus oryzae. The raw non‐waxy corn starch digestion by glucoamylase I was more difficult than the raw waxy corn starch digestion, which was also accelerated by adding α‐amylase from Aspergillus oryzae.On the other hand, another fraction, referred to as glucoamylase II, has a weak debranching activity and can not be adsorbed on raw starch. The raw waxy corn starch digestion by glucoamylase II was very weak, but was accelerated by adding α‐amylase from Rhizopus sp.

Starch Digestion with Microbial Enzymes

(1) Raw starch digestion by black-koji amylase system was studied. a) The ability of the black-koji amylase system to digest raw starch may be associated with the ability to adsorb on raw starch. b) Alpha-amylase had an extremely weak activity to digest raw starch, but glucoamylase had a strong activity to digest raw starch. c) Alpha-amylase and glucoamylase, when used jointly, interacted with each other increasing digestion of raw starch to about 3 times the sum of their separate activities. d) Glucoamylase consisted of two kinds of glucoamylase, that is, glucoamylase I and glucoamylase II. The raw waxy corn starch digestion by glucoamylase I was accelerated by adding a-amylase or isoamylase. The raw non waxy corn starch digestion by glucoamylase I was accelerated by a-amylase but not so much by isoamylase as by a-amylase. The raw waxy corn starch digestion by glucoamylase II was very weak, but was accelerated extremely by adding isoamylase, but not by a-amylase. (2) Alpha amylase adsorption on raw starch and its relation to raw starch digestion were investigated. a) Pancreatic a-amylase digested raw starch most strongly and was adsorbed on raw starch most easily. In the case of a-amylases from bacteria and malt, α-amylase adsorption curves reversed positions from those shown for digestion. b) Glucose and maltose, especially the latter, inhibite both amylase adsorption and raw starch digestion, and so the raw starch digestion was accelerated by dialysis . (3) Raw starch digestion by Rhizopus amylase system was studied. a) The glucoamylase system of Rhizopus sp. was fractionated into two kinds of glucoamylase, that is, glucoamylase I and II. b) Glucoamylase I could be adsorbed on raw starch and was highly active in raw starch digestion. The raw waxy corn starch digestion by glucoamylase I was accelerated by adding α-amylase or pullulanase. c) Glucoamylase II could not be adsorbed on raw starch. The raw waxy corn starch digestion by glucoamylase II was very weak, but was accelerated by adding α-amylase contrary to the case of glucoamylase II of black-koji.

Fractionation of the Glucoamylase System from Black‐koji Mold and the Effects of Adding Isoamylase and Alpha‐amylase on Amylolysis by the Glucoamylase Fractions

AbstractThe glucoamylase system of black koji mold was fractionated into four kinds of glucoamylase by using the corn starch adsorption technique supplement by DEAE‐cellulose column chromatography. One of these fractions, referred to as glucoamylase I, had a strong debranching activity and is highly active in raw starch digestion.The raw waxy corn starch digestion by glucoamylase I was accelerated by adding α‐amylase or isoamylase. The raw non‐waxy corn starch digestion by glucoamylase I was accelerated by α‐amylase but not so much by isoamylase as by α‐amylase.On the other hand, another fraction, referred to as glucoamylase II, had very weak debranching activity and was most feeble in the digestion of raw starch. The raw waxy corn starch digestion by glucoamylase II was very weak, but was accelerated extremely by adding isoamylase, but not by α‐amylase.

Substantiation of the criterion of relationship of sugars with starch and structural carbohydrates to crude protein in the rations of cows

Purpose. The past and present interpretation of any ratio of sugar to protein in the diet of cows of different productivity levels is unfounded. The period of sugar fermentation in the first hour after consumption of feed by cows is not subject to discussion, and in the next 6-7 hours before re-distribution of feed starch and pectins are fermented, and then hemicellulose, cellulose (crude fiber). That is, the necessary criterion for combining all fractions of carbohydrates. Methods. The substantiation of the criterion of ratio of sugars with starch and structural carbohydrates to crude protein is based on the ratio of milk protein energy to lactose energy, which is 1 to 1.25 in milk of cows with daily milk yield of 40 l and fermentation period of sugars, starch and structural carbohydrates in rumen. Because the cow rumen is an open system of microbial protein synthesis, the ratio of 1 to 1.25 is intermittent and variable. When fermenting sugar, starch and structural carbohydrates in the rumen, energy losses are known to be 15 % and then the ratio will be 1 to 1.4. The use of ATP similar to the use of energy is within 80 % and the ratio will change from 1 to 1.6. Results. Digestibility of dry corn starch in the rumen is 50 % and other cereals 77-80 %, then we have a total digestibility of 70 %, which will increase by 30 % the need for starch or it will be 6.8 kg. In this analysis of the energy balance, the ratio of crude protein to sugar, starch and part of the structural carbohydrates will be 1 to 1.7, and in natural terms (kg) 1 to 2.2. Free sugars degraded in the rumen for 30 minutes, the remaining time starch and structural carbohydrates at 3-time distribution of animal feed. Conclusions. In the energy balance, the ratio of sugars to starch and structural carbohydrates should be 10 % for sugar, 80 % starch and 10 % structural carbohydrates. For cows with a productivity of 40 liters of daily milk yield in the diet should be 1.5 kg of molasses (0.65 kg of sugar) and 6.8 kg of digestible in the rumen starch of grain components and 10 % of energy during fermentation of structural carbohydrates.

Postruminal digestion of corn starch in steers.

Postruminal digestion of corn starch in steers.

Effect of a cationic detergent on the digestion of raw cornstarch in vitro.

Effect of a cationic detergent on the digestion of raw cornstarch in vitro.