Stefan Sahlstrøm

Improved Bioavailability of Dietary Phenolic Acids in Whole Grain Barley and Oat Groat following Fermentation with Probiotic Lactobacillus acidophilus, Lactobacillus johnsonii, and Lactobacillus reuteri

The aim of this study was to improve the bioavailability of the dietary phenolic acids in flours from whole grain barley and oat groat following fermentation with lactic acid bacteria (LAB) exhibiting high feruloyl esterase activity (FAE). The highest increase of free phenolic acids was observed after fermentation with three probiotic strains, Lactobacillus johnsonii LA1, Lactobacillus reuteri SD2112, and Lactobacillus acidophilus LA-5, with maximum increases from 2.55 to 69.91 μg g(-1) DM and from 4.13 to 109.42 μg g(-1) DM in whole grain barley and oat groat, respectively. Interestingly, higher amounts of bound phenolic acids were detected after both water treatment and LAB fermentation in whole grain barley, indicating higher bioaccessibility, whereas some decrease was detected in oat groat. To conclude, cereal fermentation with specific probiotic strains can lead to significant increase of free phenolic acids, thereby improving their bioavailability.

Effects of enzyme preparations for baking, mixing time and resting time on bread quality and bread staling

Abstract Breads were made using four fungal α-amylase preparations, three different mixing times and three different resting times to study their effect on bread quality and staling. All the four enzyme preparations caused significantly darker crusts. A significant effect of resting time on crust darkness was also obtained. A tendency towards increased bread volume by enzyme addition was observed and the presence of added α-amylases seemed to decrease the effect of resting and mixing time on bread volume. Bread supplemented with enzyme preparations firmed at a lower rate, while only small effects of enzyme addition on retrogradation of starch, as expressed by enthalpy measured by differential scanning calorimetry (DSC), were observed. After 7 days, enthalpy values were significantly lower for the two shorter resting times. No significant correlation between crumb firmness and enthalpy per gram starch was found. Storage of bread increased the amount of non-susceptible starch. The lowest increase was observed for breads baked without added enzymes. The effects of mixing time and resting time on non-susceptible starch were slight.

Effects of Cultivar and Temperature During Grain Filling on Wheat Protein Content, Composition, and Dough Mixing Properties

ABSTRACT Three wheat cultivars, Bastian, Polkka, and Tjalve, were grown in growth chambers at 9, 12, 15, 18, and 21°C during grain filling in 1994, 1995, and 1996. The wheat samples were analyzed for protein content and sodium dodecyl sulfate (SDS) sedimentation volume. The mixing properties of sifted flours were determined by mixograph, and the flour protein composition was determined by size-exclusion fast protein liquid chromatography (SE-FPLC). The protein content, sedimentation volume, and mixogram parameters were affected by the temperature during grain filling. The protein content increased as the temperature increased. The sedimentation volumes and the mixograph data showed temperature effects that could not be explained by variation in protein content. The proportion of the polymeric flour proteins increased with increasing temperature. Positive correlations were found between the proportion of polymeric proteins and SDS sedimentation volume and, within each year, between the proportion of polyme...

Lactic acid fermentation of wheat and barley whole meal flours improves digestibility of nutrients and energy in Atlantic salmon (Salmo salar L.) diets

The effects of lactic acid fermentation of wheat and barley whole meal flours (WMF) on digestibility parameters in Atlantic salmon were studied. The WMFs were inoculated with a specific Lactobacillus strain and fermented for 16 h at 30 °C prior to mixing with other feed ingredients and processing by extrusion. Fermentation of the WMFs significantly decreased total starch (P<0.01) and total mixed-linked (1–3)(1–4)-β-glucan (P<0.001) contents in both cereals. Soluble β-glucans decreased (P<0.001) from 25.2 to 12.0 g kg−1 dry matter in barley WMF during fermentation. In Experiment 1, where diets with 24% untreated wheat or barley WMF and 12%, 24%, or 36% fermented WMFs were fed to Atlantic salmon (0.5 kg) for 25 days, there were indications of improved starch and fat digestibility by fermentation. Experiment 2 comprised diets containing 24% untreated or fermented wheat or barley WMFs fed to each of triplicate groups of Atlantic salmon (0.5 kg) during a 17-day experimental period. This experiment showed that protein (P<0.001), fat (P<0.05) and energy (P<0.001) were more efficiently digested in diets with wheat than in diets with barley. Apparent digestibility of starch was greatly improved by fermentation (P<0.001), more in barley diets (from 47.5% to 67.0%) than in wheat diets (from 51.7% to 65.4%). Improvements in digestibility of fat (P<0.05) and energy (P<0.001) were obtained by fermenting the cereals. The absorption of Na was higher for salmon fed wheat than barley diets (P<0.05). Fermentation resulted in improved Na absorption (P<0.01); from 68.8% to 73.2% for wheat diets and from 60.3% to 71.7% for barley diets. Fermentation caused a significant (P<0.05) improvement in Zn absorption from 32.7% to 40.5% for wheat diets and from 33.2% to 43.5% for barley diets. This may be related to the significant reduction in phytic acid levels seen in both fermented cereals (P<0.001). In conclusion, the potential of wheat and especially barley as ingredients in salmon diets is greatly improved by fermentation.

Effects of lactic acid fermentation on wheat and barley carbohydrate composition and production performance in the chicken

Effects of dietary inclusion of dried lactic acid fermented wheat or barley whole meal flours (WMF) on chicken performance were studied. WMFs were fermented for 16 h at 30 ◦ Cb y aLactobacillus strain isolated from a Norwegian rye sourdough. Four diets containing 600 g wheat WMF kg −1 (0, 200, 400 and 600 g fermented kg −1 ) and three diets containing 600 g barley WMF kg −1 (0, 400 and 600 g fermented kg −1 ) were used. Each treatment comprised 125 one-day-old sexed chickens (Ross) were fed on experimental diets until slaughtering at 35 days. Average weight, feed intake and feed:gain ratio in the 0–14, 14–35 and 0–35-day periods were recorded. At day 35, six chickens of each sex from each diet were slaughtered for determination of dressing percentage and abdominal fat. Fermentation significantly reduced levels of total and soluble dietary fibre in cereal WMF. In barley WMF, total-glucans decreased from 36.9 to 29.3 g kg −1 dry matter (DM) and soluble -glucans from 17.8 to 12.6 g kg −1 DM after fermentation. The effects of fermentation on dietary fibre and -glucans were reflected in the analysis of the experimental diets. Total starch was not significantly affected by fermentation. Cereal source and level of fermented WMF in the diets significantly affected chicken body weights. At 14 days, average weights were increased from 277 to 333 g for wheat diets, and from 252 to 322 g for barley diets, when untreated WMF was entirely substituted by fermented WMF. Linear regressions showed significant increase in average weight at 14 days with increasing levels of fermented wheat (R 2 = 0.448 ∗∗∗ ) and fermented barley (R 2 = 0.604 ∗∗∗ ). The effects of fermentation on weights at 14 days were similar for wheat and barley, as there was no significant difference between the regression slopes. Feed intake during the 0–14-day period was not significantly affected by the content of fermented cereal in the diet. Increasing level of fermented cereal significantly improved feed:gain ratio during the 0–14-day period for both

Factors Influencing Yeast Fermentation and the Effect of LMW Sugars and Yeast Fermentation on Hearth Bread Quality

ABSTRACT The purpose of this study was to investigate how wheat cultivar, growth location, type of mill, LMW sugar composition of wheat flours, mixing time, and type of mixer affected yeast fermentation. Also studied was the effect of yeast fermentation and LMW sugar composition on hearth bread quality. To achieve this, 36 different flours were produced from two different mills using six different wheat cultivars grown at three locations. Yeast fermentation in doughs, measured as gas production, was determined using realtime pressure measurements and GasSmart software. A short mixograph mixing or spatula mixing was not efficient enough to rehydrate instant dry yeast. Compressed yeast and a short mixing time were enough to reach maximum fermentation rate. Maximum pressure after 210 min of fermentation was higher for instant dry yeast than for compressed yeast. Wheat cultivar and growth location had a significant effect on LMW sugar composition. Wheat cultivar, growth location, and type of mill used signifi...

Effect of Dough Processing Conditions and DATEM on Norwegian Hearth Bread Prepared from Frozen Dough

ABSTRACT The objective of this study was to examine treatments that directly influence Norwegian lean doughs destined to be frozen. Therefore a strip-block experimental design with four dough treatment factors (wheat flour blend, diacetyl tartaric acid esters of monoglycerides [DATEM], water absorption, and dough temperature) and two storage factors (frozen storage time and thawing time) was used. Four levels were selected for frozen storage time and two levels were selected for the remaining factors. After frozen storage (2–70 days), the doughs were thawed and baked. Principal component analysis showed that to obtain a high loaf volume and bread score after freezing, a high dough temperature after mixing (27°C) was essential. The highest form ratio (height/width) level was obtained after 28 days of frozen storage and with a short thawing time (6 hr). Analysis of variance (ANOVA) of dough treatments showed that an increase in dough temperature from 20 to 27°C after mixing resulted in a significant increas...

Activation and inhibition of nuclear factor kappa B activity by cereal extracts: role of dietary phenolic acids.

The transcription factor nuclear factor kappa B (NF-kappaB) plays a critical role in stress, immune, and inflammatory responses, and the modulation of its activity can be a potentially effective preventive strategy for controlling certain diseases. Cereal grains contain phenolic compounds in concentrations comparable to those in fruits and vegetables, well-known for their beneficial effect on human health. In this study we aimed to examine the effect of different phenolic extracts from barley, oat, wheat, and buckwheat on the modulation of basal and lipopolysaccharide (LPS)-induced NF-kappaB activity and elucidate the role of phenolic acids in this modulation. Three extracts were prepared: extracts of free phenolic compounds (M1), extracts of free phenolic acids (M2), and extracts of bound phenolic acids (HY). Generally, extracts M2 showed the highest effect on modulation of NF-kappaB activity with strong inhibition of LPS-induced NF-kappaB activity at all concentrations and of the basal NF-kappaB activity at concentrations equal to or lower than 3 mg/mL. Most of extracts M1 and HY slightly increased both the basal and the LPS-induced NF-kappaB activation. However, at the highest concentrations (3 or 15 mg/mL) extracts HY inhibited LPS-induced NF-kappaB activation. Similar experiments with standard solutions of phenolic acids indicated their ability to modulate the NF-kappaB activity.

Influence of starch, gluten proteins and extraction rate on bread and pasta quality

Abstract Wholemeal products and white products of bread and pasta were made of the same material consisting of a set of bread wheat varieties. The protein content varied little, whereas the protein quality varied significantly among the varieties. The composition of the high molecular weight glutenin subunits and a set of gliadins could explain most of the variations in Zeleny sedimentation volume, farinogram data and bread quality. Total amylose content in white flour varied significantly among the wheat varieties. All varieties with good protein quality gave good bread quality. Among those with poor protein quality, one had higher and one had lower total amylose content than average, and both gave poor baking results. Small differences in gelatinization temperature and gelatinization enthalpy were observed among the wheat varieties. The gelatinization temperature was slightly higher in wholemeal flour than in white flour, whereas the gelatinization enthalpy was lower in the former. White flour from bread wheat gave pasta of unacceptable quality, whereas the quality of pasta made from wholemeal flour was close to that of commercial pasta made from wholemeal durum wheat. The poor pasta quality of the white bread flours may be attributed to the fine granulometry of the flours. Variations in pasta quality and bread quality between different varieties were not correlated. T-8020 and Bastian with the same protein quality characteristics and the same bread quality gave pasta of different qualities.

Phenolic contents and antioxidant activities in covered whole-grain flours of Norwegian barley varieties and in fractions obtained after pearling

Abstract Phenolic contents and corresponding antioxidant activities were studied in covered whole-grain flours of Norwegian barley varieties and in two different pearling fractions. In covered whole-grain flours the summarized amount of phenolics (Σ-P) ranged from 481–676 mg gallic acid equivalent (GAE)/100 g dry matter (DM) and the corresponding total antioxidant activities (Σ-FRAP) between 6.1–8.7 mmol Fe3 +/100 g DM. About 50% of the phenolics in these samples were easily extractable (free). Upon pearling a general decrease in both Σ-P and Σ-FRAP was seen in the pearled samples, while the ratio between free and bound phenolics was similar or increased to those in the covered whole-grain samples. The hulls had the highest Σ-P and Σ-FRAP and were dominated by bound phenolics. Despite accounting for only 10–20% of the total grain weight, the hulls typically contributed to 45% of the total antioxidant capacity measured in the covered whole-grain flours. Pearling makes it possible to obtain barley fractions with different amounts of phenolics, different ratios of free and bound phenolics, and thus different antioxidant activities.