Introduction: Short chain fatty acids (SCFA) are produced by large bowel fermentation of dietary carbohydrates including resistant starch (RS) and non-starch polysaccharides (NSP). SCFA (particularly butyrate) play a major role in maintaining large bowel function and may reduce the incidence of colonic disease. Butyrate is the preferred metabolic substrate of colonocytes and is believed to play a key role in modulating epithelial cell cycle, mucosal immune response and gut motility. Increasing large bowel butyrate supply requires intakes of NSP or (RS) much higher than those currently consumed in western diets. Recent studies have shown large bowel butyrate is increased by the ingestion of butyrylated starch but the characteristics and physiological effects of its ingestion in animal models of colonic disease have not yet been investigated. Aims and Methods: The experiments in in vitro and in rats described in this thesis examined: the effects of production techniques and cooking on the capacity of butyrylated starch to deliver butyrate to the large bowel. They investigated the effects of increased butyrate levels on large bowel function in: (i) normal rats, (ii) the dextran sulphate sodium (DSS) rat model of ulcerative colitis (UC) and (iii) the high dietary protein rat model of colonocyte genetic damage. Results: Starch type, pre-treatment and the degree of butyrylation influenced the in vitro digestion and fermentation characteristics of butyrylated starch before and after cooking. Butyrylated starch was less susceptible to small intestinal digestion RS as than high amylose maize starch (HAMS) in vitro. Feeding diets containing 10% cooked butyrylated starch delivered significantly greater amounts of butyrate to the large bowel of rats than 10% raw or cooked HAMS. Butyrate did not influence colonocyte proliferation throughout the large bowel of the rat but increased distal colonic IL-18 concentrations and decreased longitudinal smooth muscle contractility. Feeding HAMS or butyrylated HAMS (HAMSB) to rats during DSS induced UC and during 7 days of recovery resulted in increased mucosal damage compared to low amylose maize starch (LAMS) fed rats. When rats were fed HAMS or HAMSB during the 7 days of recovery only, there was no significant difference in mucosal damage. Genetic damage, as measured by the comet assay, was 2 fold higher in rats fed high protein diet compared with those fed a low protein diet. Concurrent feeding of high protein and either HAMS or HAMSB resulted in significantly less genetic damage. Genetic damage in rats fed 20% HAMSB was half the levels of the 20% HAMS group, and was the same as the low protein diet. Conclusions: Butyrylated starch delivered butyrate to the large bowel in rats effectively, was less susceptible to small intestinal digestion and had greater stability following cooking than the unmodified base starch. Increased digesta butyrate did not affect large bowel function or colonocyte proliferation in the normal rat; the effects on mucosal damage in the DSS rat model of ulcerative colitis were inconclusive. Increased luminal butyrate prevented high-protein induced colonocyte genetic damage. Butyrylated starches have potential to assist with the maintenance of bowel health and to contribute to reduced risk of colonic disease in the community. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320754 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008

Until recently, the viscoamylograph had been the primary method for measuring starch as it relates to noodle quality in wheat. This method requires a large sample of flour and is time consuming. With the introduction of the rapid visco-analyser (RVA) in 1986 and the more recent flour swelling volume procedure, both the time to determine starch quality and the sample size required have been reduced Parents, reciprocal F���, and backcross generations from a cross involving two white wheat lines were space-planted to study the association among the three procedures for measuring noodle starch quality. Grain protein and hardness and plant height also were measured. Differences among the generations were observed for the viscoamylograph, flour swelling volume, and plant height. Coefficients of variation were low for both flour swelling volume and plant height. A significant positive association was found between the viscoamylograph and the RVA (r=0.61). This indicates that for the populations evaluated in this study the RVA can be used in place of the viscoamylograph to measure starch quality. The RVA values, however, varied greatly between years suggesting a large environmental influence. There was also evidence for a genotype by environment interaction. No maternal effects were noted between reciprocal crosses. Conflicting results were found for the association between the flour swelling volume procedure and the RVA and viscoamylograph. Further experiments are required to clarify the possible association between flour swelling volume and other starch quality tests. Such experiments may have to be delayed until the F��� or F��� generations when adequate amounts of flour can be obtained from more genetically uniform lines. / Graduation date: 1997

Thesis (Ph. D.)--Landbouwhogeschool te Wageningen, 1981. / Summary in Dutch. Includes bibliographical references (p. 170-176).

The nutritional value of distillers dried grains with solubles (DDGS) has not been assessed in swine. The nutritional value of corn and wheat DDGS, and possibilities to improve the nutritional value of wheat DDGS were for swine were investigated in two studies. <p>In study 1, two experiments were conducted to determine digestibility and digestible contents of energy, amino acids (AA) and P in corn and wheat DDGS and wheat grain, together with N and P excretion and growth performance in grower-finisher pigs. In experiment 1, 12 barrows (64.6 ± 6.4 kg) were fitted with ileal T-cannulae and had restricted access (2.6 x maintenance) to a wheat control diet or one of three diets with 40% corn, wheat+corn (4:1) or wheat DDGS. For energy, apparent total tract digestibility was highest for wheat (85%; P < 0.05) and did not differ among DDGS (77 to 79%; P > 0.10). Total tract digestible energy (DE) was highest for corn DDGS (4292 kcal kg-1 DM; P < 0.05) and tended to differ among wheat+corn and wheat DDGS and wheat (4038, 4019, and 3807, respectively; P = 0.06). For lysine, apparent ileal digestibility (AID) was highest for wheat (71%; P < 0.05) and did not differ among DDGS (59 to 63%; P > 0.10). The apparent ileal digestible lysine content was highest for corn DDGS (0.51% DM; P < 0.05), intermediate for wheat+corn and wheat DDGS (0.45 and 0.42), and lowest for wheat (0.37%). For P, total tract digestibility was lowest for wheat (15%; P < 0.05) and did not differ among DDGS samples (53 to 56%; P > 0.10). Total N excretion was highest for wheat+corn and wheat DDGS (55 and 58 g d-1; P < 0.05), intermediate for corn DDGS (44) and lowest for wheat (36). Total P excretion did not differ among DDGS (11 g d-1) and was lowest for wheat (8; P < 0.05). In experiment 2, 100 pigs (52.0 ± 3.3 kg) were fed a wheat-pea control diet or one of three 25%-DDGS (corn, wheat+corn or wheat) diets (3.375 Mcal DE kg-1; 2.50 g AID lysine Mcal-1 DE) for 5 wk. Overall, average daily feed intake (ADFI) and daily gain (ADG) were higher for wheat than DDGS (P < 0.05) but feed efficiency did not differ (P > 0.10). In summary, the nutritional value of wheat DDGS for swine is higher than wheat and lower than corn DDGS and feeding DDGS reduced growth performance, partly via a reduced ADFI, indicating that anti-nutritional factors in DDGS require further investigation.<p>In study 2, the effect of xylanase supplementation of wheat DDGS on nutrient digestibility and nutrient excretion was evaluated in grower-finisher pigs. Wheat-based diets with or without 40% wheat DDGS were tested with or without supplementary xylanase (4,000 U kg-1 feed) as a 2 x 2 factorial arrangement in a repeated Latin square design using eight barrows (29.4 ± 2.0 kg) fitted with ileal T-cannulae. Following a 6-day acclimation, faeces and urine were collected for 3 d, and ileal digesta for 2 d. The apparent ileal energy digestibility and DE content were not affected either by ingredient or xylanase (P > 0.05). The total tract energy digestibility and DE content were affected by ingredient (P > 0.05), but not by xylanase (P > 0.05). The total-tract energy digestibility was higher for wheat, but DE content was higher for wheat DDGS. The AID of arginine, isoleucine, leucine, phenylalanine, threonine, tryptophan and total AA were higher (P < 0.05), and of cysteine, histidine and lysine were similar (P > 0.05), and SID of phenylalanine was higher (P < 0.05), and of the other AA was similar (P > 0.10) for wheat DDGS compared to wheat. Supplementary xylanase improved AID and SID of most of the indispensable AA in wheat (P < 0.05), but not in wheat DDGS (P > 0.05). The apparent and standardized ileal AA contents were affected by ingredients (P < 0.05), but not by xylanase (P > 0.05). Digestible AA contents were higher for wheat DDGS than for wheat. The digestibility and digestible content of P were affected by ingredient and xylanse (P < 0.05). The P digestibility and digestible P contents were higher for wheat DDGS compared to wheat. Neither ingredient nor supplementary xylanase affected DM intake (P > 0.05). The DM excretion on daily basis and as a percentage of intake were affected by ingredient (P < 0.05), but not by xylanase (P > 0.05). Ingredients affected all N and P variables (P < 0.05), except percentage retained for both nutrients (P > 0.05). None of N variables (P > 0.05), but P intake and, retention on daily basis and as a percentage of intake were affected by xylanase (P < 0.05). The DM excretion and N and P intake, excretion and daily retention were higher for wheat DDGS compared to wheat. Lack of beneficial response to supplementary xylanase might be due to inappropriate enzyme level or insufficient substrate level of wheat DDGS. In addition, unidentified factors associated with fermentation and drying processes might constrain the nutritional value of wheat DDGS. Further studies are required to determine the proper xylanase inclusion level and/or to identify the factors associated with reduced nutrient digestibility of wheat DDGS.

No description available.

No description available.

Specific enzymes have been used to improve flour quality for bread but enzyme action in tortilla flour has not been investigated. Two different wheat flours were prepared into tortillas using laboratory-scale, commercial equipment with fixed processing parameters. Dough and tortilla properties were evaluated using subjective and objective methods. Tortillas were stored in plastic bags at 22°C for evaluation. The effects of nine enzymes (amyloglucosidase 1, amyloglucosidase 2, bacterial 1, bacterial 2, fungal, maltogenic 1, maltogenic 2, malted barley and xylanase) on quality of wheat flour tortillas were evaluated. Dough absorption was adjusted to attain uniform dough for tortillas. Enzyme addition to tortilla flour did not significantly affect tortilla weight, moisture and pH. Bacterial 2 amylase extended shelf stability while maltogenic 1 and xylanase exhibited smaller improvements in shelf stability and other tortilla properties. Addition of 0.05 activity unit bacterial 2 amylase improved tortilla diameter and improved tortilla shelf life from 12 to 28 days. Maltogenic 1 at 280 ppm improved tortilla diameter, opacity and shelf life. Addition of 100 ppm of xylanase effectively improved tortilla diameter and shelf life. Bacterial 1 amylase at 60 ppm improved tortilla diameter but did not improve shelf stability. Amyloglucosidase 2, maltogenic 2 and malted barley amylase did not improve tortilla quality at any of the evaluated levels. Amyloglucosidase 1 and fungal amylase reduced overall tortilla quality at all the evaluated levels. Bread-making quality of wheat flour is correlated with the damaged starch present in the flour. Damage was induced by grinding the samples for 0, 1, 4 and 8 hr to determine the effects of starch damage on tortilla quality. Processing increased starch damage of control tortilla flour from 5.4% to 12.6%. Damage starch increased dough water absorption, toughness and press rating and reduced diameter and opacity of tortillas. Damage starch improved tortilla rollability at higher levels but did not improve tortilla properties in combination with bacterial 2 amylase. Overall tortilla quality was not improved due to additional starch damage. Improved tortilla quality using bacterial 2 amylase at very low levels could be commercialized.

The nutritional value of distillers dried grains with solubles (DDGS) has not been assessed in swine. The nutritional value of corn and wheat DDGS, and possibilities to improve the nutritional value of wheat DDGS were for swine were investigated in two studies. <p>In study 1, two experiments were conducted to determine digestibility and digestible contents of energy, amino acids (AA) and P in corn and wheat DDGS and wheat grain, together with N and P excretion and growth performance in grower-finisher pigs. In experiment 1, 12 barrows (64.6 ± 6.4 kg) were fitted with ileal T-cannulae and had restricted access (2.6 x maintenance) to a wheat control diet or one of three diets with 40% corn, wheat+corn (4:1) or wheat DDGS. For energy, apparent total tract digestibility was highest for wheat (85%; P < 0.05) and did not differ among DDGS (77 to 79%; P > 0.10). Total tract digestible energy (DE) was highest for corn DDGS (4292 kcal kg-1 DM; P < 0.05) and tended to differ among wheat+corn and wheat DDGS and wheat (4038, 4019, and 3807, respectively; P = 0.06). For lysine, apparent ileal digestibility (AID) was highest for wheat (71%; P < 0.05) and did not differ among DDGS (59 to 63%; P > 0.10). The apparent ileal digestible lysine content was highest for corn DDGS (0.51% DM; P < 0.05), intermediate for wheat+corn and wheat DDGS (0.45 and 0.42), and lowest for wheat (0.37%). For P, total tract digestibility was lowest for wheat (15%; P < 0.05) and did not differ among DDGS samples (53 to 56%; P > 0.10). Total N excretion was highest for wheat+corn and wheat DDGS (55 and 58 g d-1; P < 0.05), intermediate for corn DDGS (44) and lowest for wheat (36). Total P excretion did not differ among DDGS (11 g d-1) and was lowest for wheat (8; P < 0.05). In experiment 2, 100 pigs (52.0 ± 3.3 kg) were fed a wheat-pea control diet or one of three 25%-DDGS (corn, wheat+corn or wheat) diets (3.375 Mcal DE kg-1; 2.50 g AID lysine Mcal-1 DE) for 5 wk. Overall, average daily feed intake (ADFI) and daily gain (ADG) were higher for wheat than DDGS (P < 0.05) but feed efficiency did not differ (P > 0.10). In summary, the nutritional value of wheat DDGS for swine is higher than wheat and lower than corn DDGS and feeding DDGS reduced growth performance, partly via a reduced ADFI, indicating that anti-nutritional factors in DDGS require further investigation.<p>In study 2, the effect of xylanase supplementation of wheat DDGS on nutrient digestibility and nutrient excretion was evaluated in grower-finisher pigs. Wheat-based diets with or without 40% wheat DDGS were tested with or without supplementary xylanase (4,000 U kg-1 feed) as a 2 x 2 factorial arrangement in a repeated Latin square design using eight barrows (29.4 ± 2.0 kg) fitted with ileal T-cannulae. Following a 6-day acclimation, faeces and urine were collected for 3 d, and ileal digesta for 2 d. The apparent ileal energy digestibility and DE content were not affected either by ingredient or xylanase (P > 0.05). The total tract energy digestibility and DE content were affected by ingredient (P > 0.05), but not by xylanase (P > 0.05). The total-tract energy digestibility was higher for wheat, but DE content was higher for wheat DDGS. The AID of arginine, isoleucine, leucine, phenylalanine, threonine, tryptophan and total AA were higher (P < 0.05), and of cysteine, histidine and lysine were similar (P > 0.05), and SID of phenylalanine was higher (P < 0.05), and of the other AA was similar (P > 0.10) for wheat DDGS compared to wheat. Supplementary xylanase improved AID and SID of most of the indispensable AA in wheat (P < 0.05), but not in wheat DDGS (P > 0.05). The apparent and standardized ileal AA contents were affected by ingredients (P < 0.05), but not by xylanase (P > 0.05). Digestible AA contents were higher for wheat DDGS than for wheat. The digestibility and digestible content of P were affected by ingredient and xylanse (P < 0.05). The P digestibility and digestible P contents were higher for wheat DDGS compared to wheat. Neither ingredient nor supplementary xylanase affected DM intake (P > 0.05). The DM excretion on daily basis and as a percentage of intake were affected by ingredient (P < 0.05), but not by xylanase (P > 0.05). Ingredients affected all N and P variables (P < 0.05), except percentage retained for both nutrients (P > 0.05). None of N variables (P > 0.05), but P intake and, retention on daily basis and as a percentage of intake were affected by xylanase (P < 0.05). The DM excretion and N and P intake, excretion and daily retention were higher for wheat DDGS compared to wheat. Lack of beneficial response to supplementary xylanase might be due to inappropriate enzyme level or insufficient substrate level of wheat DDGS. In addition, unidentified factors associated with fermentation and drying processes might constrain the nutritional value of wheat DDGS. Further studies are required to determine the proper xylanase inclusion level and/or to identify the factors associated with reduced nutrient digestibility of wheat DDGS.

No description available.

No description available.