Birgitta Sundberg

Stability of Oat Avenanthramides

ABSTRACT The three main oat avenanthramides, N-(4′-hydroxy)-(E)-cinnamoyl-5-hydroxyanthranilic acid (Bp), N-(4′-hydroxy-3′-methoxy)-(E)-cinnamoyl-5-hydroxyanthranilic acid (Bf), and N-(3′,4′-dihydroxy)-(E)-cinnamoyl-5-hydroxyanthranilic acid (Bc), and their corresponding cinnamic acids, p-coumaric (P), ferulic (F), and caffeic (C), were investigated for stability to pH, temperature, and UV-light treatment. The retention of the avenanthramides after processing of oat-based food products was also analyzed. The avenanthramide Bc and the cinnamic acid C were sensitive to alkali and neutral conditions, especially in combination with heat treatment, whereas the other compounds studied were more stable. The cinnamic acids but not the avenanthramides were isomerized when irradiated with UV-light. The avenanthramides were restored after processing of oat-based products.

Effect of fat emulsion (Fabuless) on orocecal transit time in healthy men

Background. Given the growing prevalence of overweight and related health consequences, there is increased interest in the search for novel dietary strategies for weight control. A food ingredient, an emulsion based on palm and oat oil (Fabuless, previously known as Olibra), has been associated with short-term reductions of food intake, induction of satiety, alternation in the satiety hormones, as well as long-term effects on weight control. The mechanism by which it can exert these effects is so far unclear, though it has been suggested that the “ileal break” may play a role in increasing gastrointestinal transit time. The aim of this study was to investigate the effects of this stable fat emulsion on orocecal transit time in healthy men. Material and methods. In a controlled, double-blind, cross-over-designed study, 15 healthy men (aged 20–59 years, body mass index (BMI) 22–28), randomly allocated to two treatments, consumed the stable fat emulsion or a milk fat in yoghurt during two days of investigation, with an interval of 1 week. Orocecal transit time was determined by following blood sulfapyridine levels, which is a metabolite of salazopyrine in the colon. Results. A statistically significant delay in the appearance of sulfapyridine in serum was obtained after active treatment versus control treatment, corresponding to a 45-min longer orocecal transit time due to fat emulsion consumption. Conclusions. This study provides the first evidence to suggest that this stable fat emulsion may affect the ileal brake mechanism by slowing down the gastrointestinal transit time, which might explain the weight control and appetite suppression previously observed in association with this emulsion.

Substrates available for colonic fermentation from oat, barley and wheat bread diets. A study in ileostomy subjects

Nutrients not absorbed in the small bowel will form substrates for microbial growth in the colon which may have implication for the development of colon cancer. The aim of the present study was to investigate whether fibre-rich oat and barley diets increase the excretion of energy-supplying nutrients from the small bowel compared with a low-fibre wheat diet, and whether a possible increase could be related to the beta-glucan content. Nine ileostomy subjects were served four types of bread together with a low-fibre basal diet (12 g dietary fibre/d). The breads were based on either wheat flour (W diet, 7 g dietary fibre/d), oat bran (OB diet, 29 g dietary fibre/d), the same amount of oat bran with addition of beta-glucanase (EC 3.2.1.4) (OBE diet, 19 g dietary fibre/d) or a fibre-rich barley fraction (B diet, 35 g dietary fibre/d). An increased ileal excretion of starch was observed with the barley diet but no effect of the oat beta-glucan on starch recovery was found. The NSP + Klason lignin in the ileostomy effluents accounted only for 24, 31, 24 and 35% of the gross energy excretion in the W, OB, OBE and B diet periods respectively. A large part of the dry weight and energy (30, 21, 28 and 27%, in the W, OB, OBE and B diets respectively) in the effluents could not be identified as fat, protein, total starch or NSP + Klason lignin. This unidentified part was probably made up of oligosaccharides, endogenous losses and nutrient complexes. Methods for identifying and analysing these components should be developed and their role as substrates for colonic fermentation and colon cancer development ought to be investigated.

Whole grain rye porridge breakfast improves satiety compared to refined wheat bread breakfast.

Background Previous studies show that dietary fibre-rich foods with low energy density have a stronger effect on satiety per calorie compared to more energy dense foods. Objective To investigate subjective appetite and voluntary energy intake (24 h) after consumption of rye porridge breakfast and pasta lunch made from whole grain compared to iso-energetic reference meals made from refined cereals: wheat bread breakfast and wheat pasta lunch. Subjects In all, 22 healthy subjects, 14 females and 8 males, aged 21–64 years, BMI ranging from 18.7 to 27.5 kg/m2, participated. Design A randomised, crossover design was used. Appetite was rated by visual analogue scales (VAS) regularly from just before breakfast (08:00) until bedtime. An ad libitum dinner was served at 16:00. After leaving the clinic and in the morning day 2, subjects recorded foods consumed. Results Whole grain rye porridge gave a significantly prolonged satiety, lowered hunger and desire to eat (p<0.05 in most point estimates) up to 8 h after consumption compared to the refined wheat bread. The two pasta lunch meals did not vary in their effects on appetite ratings. There was no significant effect on ad libitum energy intake at 16:00 or self-reported energy and macronutrient intake in the evening and breakfast meal on day 2. Conclusions Whole grain rye porridge at breakfast has prolonged satiating properties up to 8 h after consumption compared to refined wheat bread, but did not diminish subsequent food intake.

High-fiber rye diet increases ileal excretion of energy and macronutrients compared with low-fiber wheat diet independent of meal frequency in ileostomy subjects.

Background Whole-grain foods and cereal dietary fiber intake is associated with lower body weight. This may partly result from lower energy utilization of high-fiber diets. Objective In the present study, the impact on ileal excretion of energy and macronutrients in response to a rye bread high-fiber diet compared to a refined wheat low-fiber diet was investigated. Furthermore, the effect of meal frequency on apparent absorption of nutrients was studied for the first time. Design Ten participants that had undergone ileostomy consumed standardized iso-caloric diets, including low-fiber wheat bread (20 g dietary fiber per day) for 2 weeks followed by high-fiber rye bread (52 g dietary fiber per day) for 2 weeks. The diets were consumed in an ordinary (three meals per day) and a nibbling (seven meals per day) meal frequency in a cross-over design. Ileal effluents were collected during 24 h at the third day of each of the four dietary periods and analyzed for gross energy and nutrient contents. Results The results showed that intake of rye bread high-fiber diet compared to the refined wheat low-fiber diet caused an increase in ileal excretion of energy and macronutrients. The effect was independent of meal frequency. This suggests that a high intake of rye may result in lower availability of macronutrients for small intestinal digestion and absorption. A regular intake of rye may therefore have implications for weight management.

Effect of 2 pieces of nutritional advice on folate status in Swedish women: a randomized controlled trial

BACKGROUND Ten years after the introduction of mandatory folic acid fortification in the United States, Canada, and Costa Rica, the issue is still under debate in several countries, and Sweden recently decided against mandatory fortification. OBJECTIVE The objective was to determine the folate status of women after an intervention involving 2 Swedish dietary recommendations: a food recommendation (bread) and a complete meal recommendation (breakfast). DESIGN Fifty-one free-living women with normal folate status participated in a 12-wk controlled intervention trial. Subjects were randomly assigned to one of the following interventions: apple juice (control group; n = 17), a breakfast providing 125 microg folate (breakfast group; n = 17), or 5 slices of whole-meal bread to be eaten over the course of the day, which provided 70 microg folate (bread group; n = 17). Folate status was assessed on the basis of concentrations of erythrocyte folate, serum folate, and plasma total homocysteine (tHcy) at baseline and at weeks 8 and 12 of the trial. RESULTS In the breakfast group, initial median concentrations of erythrocyte folate (805 nmol/L) increased by 172 nmol/L (95% CI: 24, 293; P = 0.02) relative to the control. The relative increase in initial serum folate (2 nmol/L, 95% CI: 0, 5; P = 0.06) was nonsignificant. The initial tHcy concentration (8.7 micromol/L) decreased by 2.3 micromol/L (95% CI: -1, -3.4; P < 0.01). In the bread group, the initial tHcy concentration (9.1 micromol/L) decreased nonsignificantly by 1.4 micromol/L (95% CI: 0, -2.8; P = 0.08) relative to the control group, whereas other outcomes were stable. CONCLUSIONS The folate status of the subjects improved after regular consumption of the breakfast meal. The additional folate intake from the bread maintained the folate status but was not sufficient to improve it.

Glycaemic responses and hypocholesterolaemic effects of high‐amylose barley diets on broiler chicks

The glucose and lipid responses of barley diets were investigated with chicks based on either flour or red dog (RD) from each of three barley cultivars, Glacier, covered high-amylose Glacier (HAG) and hull-less high-amylose Glacier (HHAG), with two maize control diets. Mean time interval blood glucose levels were higher (P < 0.05) for chicks fed uncooked barley flour or RD, compared with controls. Total and LDL plasma cholesterol were lower (P < 0.05) for chicks fed the HAG and HHAG flour and all barley RD diets. HDL cholesterol values for chicks fed Glacier and HHAG flour and HHAG RD diets were higher than controls. The LDL/HDL cholesterol ratios for chicks fed HAG and HHAG flour and all barley RD diets were lower (P < 0.05) than controls. Lower body weights were observed in all chickens fed barley diets. The results suggest that the soluble fibre, mainly β-glucan and starch structures, in barley may be responsible for the hypocholesterolaemic effect.

Quality of rolled barley flakes as affected by batch of grain and processing technique

Rolled barley flakes were prepared from three different batches of grain by pearling, steaming and rolling. Autoclaved and malted barleys from the three batches were also processed in the same way. Analysis of the nine products showed that both batch of barley and process had significant effects on chemical composition and viscosity. Puddings were prepared from the products and mechanical consistency, juiciness and grain consistency were graded on both newly prepared and heated puddings by a sensory taste panel. Batch of barley had no effect on mechanical consistency but significant effects on juiciness and grain consistency. Type of processing had significant effect on all three parameters for both newly prepared and heated puddings.