Physicochemical properties, anti-nutritional and bioactive constituents, in vitro digestibility, and techno-functional properties of bioprocessed whole wheat flour

This study investigated the impact of bioprocessing techniques (germination, solid-state fermentation, the combination of germination, and solid-state fermentation) on the physicochemical properties, anti-nutritional and bioactive constituents, in vitro digestibility, and techno-functional properties of whole wheat grains were investigated. Bioprocessed whole wheat flour (WWF) samples and the raw flour (control) were prepared using standard procedures. Proximate, anti-nutritional, mineral and amino acid (AA) compositions, protein digestibility, antioxidant activities, starch characteristics, and techno-functional properties were studied using standard methods. The bioprocessing methods increased (p ≤ 0.05) the protein (13.37-16.84 g/100 g), total dietary fiber, mineral constituents, resistant starch (7.19-9.87 g/100 g), slowly digestible starch, phenolic content, antioxidant activities (ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity), most AAs, and protein digestibility. Also observed were decreases (p ≤ 0.05) in rapidly digestible starch, phytic acid, tannin, and trypsin inhibitor activity. The adopted bioprocessing techniques modified the thermal, functional, color, and pasting properties of the WWF and resulted in molecular interactions in some functional groups, as revealed by Fourier transform infrared spectroscopy, compared to the raw flour. The combination of germination and fermentation improved the physicochemical (titratable acidity = 4.93%), protein (16.84/100 g) and starch digestibility (resistant starch = 9.87%), antioxidant (FRAP = 78.90 mg/GAE/100 g), and mineral contents (calcium = 195.28 mg/100 g), modified the pasting (peak viscosity = 90.34 RVU), thermal (peak temperature = 64.82°C), and color properties of WWF with reduced anti-nutritional factors. The combination of these processing techniques could serve as a natural and low-cost technique for the modification of whole wheat functionality and subsequently as an improved functional ingredient during food product development.

Effects of Protein Source, Whole Wheat and Butyric Acid on Live Performance, Gut Health and Amino Acid Digestibility in Broiler Chickens

A total of 896 1-day-old straight-run (Ross-308) broilers were used to investigate the interactive effects of protein source (PS), diet structure (DS) and butyric acid (BA) on live performance and carcass characteristics, gut development and its morphology and apparent ileal digestibility (AID) of protein and amino acids (AA). Eight experimental diets comprising 8 replicates with 14 birds each were tested in a 2 × 2 × 2 factorial arrangement with complete randomized design by two levels of BA (0 and 0.1%), two forms of DS (whole vs. ground wheat) and two PS, i.e., soybean meal and canola meal (SBM vs. CM). Throughout the entire experimental period (0 to 35 d), broilers fed SBM-based diets exhibited better (p < 0.05) growth performance (feed intake (FI), body weight gain (BWG) and feed conversion ratio (FCR)), carcass parameters (p < 0.05), gut health (p < 0.05), and nutrient digestibility (p < 0.05) than CM-fed broilers. Dietary whole wheat (WW) positively affected FI (p = 0.001), BWG (p = 0.004) and FCR (p = 0.035) during the overall experimental period. Broilers fed WW had 6, 5, 8, 11 and 10% lower empty relative weights of crop, proventriculus, jejunum, ileum and colon and 25 and 15% heavier gizzard and pancreas, respectively, with longer villus height (p < 0.001), reduced crypt depth (p = 0.031) and longer villus height-to-crypt depth ratio (p < 0.001) than those fed ground-wheat-based diets. Broilers fed WW had greater (p < 0.05) AID of CP and most of the AA. Butyric acid supplementation resulted in improved (p < 0.05) growth performance and digestibility of threonine, valine, leucine, isoleucine, phenylalanine, serine and aspartate. The broilers consuming SBM had 28% lower abdominal fat than those fed CM-based diets. In conclusion, harmful consequences of a less digestible PS can partially be compensated by the inclusion of WW, and supplementation of BA further reduces these detrimental effects.

Carbohydrate utilization by the gut microbiome determines host health responsiveness to whole grain type and processing methods

Little is known about how interactions among grain processing, grain type, and carbohydrate utilization (CU) by the microbiome influence the health benefits of whole grains. Therefore, two whole grains - brown rice and whole wheat - and two processing methods - boiling (porridge) and extrusion - were studied for their effects on host metabolic outcomes in mice harboring human microbiomes previously shown in vitro to have high or low CU. Mice carrying either microbiome experienced increases in body weight and glycemia when consuming Western diets supplemented with extruded grains versus porridge. However, mice with the high but not low CU microbiome also gained more weight and fat over time and were less glucose tolerant when consuming extruded grain diets. In high CU microbiome mice, the exacerbated negative health outcomes associated with extrusion were related to altered abundances of Lachnospiraceae and Ruminococcaceae as well as elevated sugar degradation and colonic acetate production. The amplicon sequence variants (ASVs) associated with extruded and porridge diets in this in vivo study were not the same as those identified in our prior in vitro study; however, the predicted functions were highly correlated. In conclusion, mice harboring both high and low CU microbiomes responded to the whole grain diets similarly, except the high CU microbiome mice exhibited exacerbated effects due to excessive acetate production, indicating that CU by the microbiome is linked to host metabolic health outcomes. Our work demonstrates that a greater understanding of food processing effects on the microbiome is necessary for developing foods that promote rather than diminish host health.Abbreviations: CU- carbohydrate utilization; SCFA- short-chain fatty acids; GF- germ-free; HMA, human-microbiome associated; ipGTT- intraperitoneal glucose tolerance test; HOMA-IR- Homeostatic Model Assessment for Insulin Resistance; AUC- area under the glycemia curve; ASV- amplicon sequence variant; lf- low-fat; wd- Western diet; wd_wwp- Western diet containing whole wheat porridge; wd_wwe- Western diet containing whole wheat extrudate; wd_bre- Western diet containing brown rice extrudate; wd_extr- Western diet containing either whole wheat or brown rice extrudate.

Individual effects of enzymes and vital wheat gluten on whole wheat dough and bread properties

The objective of this research was to determine effects of five enzymes on whole wheat bread properties, particularly loaf volume, bread texture, and staling. Enzymes containing conventional α-amylase (α-amyl), cellulase (cel), glucose oxidase, maltogenic α-amylase (m amyl), and xylanase (xyl) were added at three levels. Vital wheat gluten (VWG) was added as an additional, separate treatment at 2.5% (flour weight basis). Enzymes had minimal effect on water absorption and mixing time. Each enzyme increased specific loaf volume for at least one of the usage levels tested (P < 0.01). Among the enzyme treatments, the greatest loaf volume was seen for xyl at the medium and high levels. No enzyme was as effective as VWG at increasing loaf volume. Overall, enzymes did not significantly change cell structure. The greatest reduction in fresh bread hardness was obtained for the high level of xyl. VWG, m amyl, and xyl reduced the rate of bread firming over 7 days. α-Amyl, cel, and m amyl decreased starch retrogradation at day 7 as measured by differential scanning calorimetry (P < 0.01). M amyl nearly eliminated the endothermic peak for recrystallized amylopectin. This study demonstrated the specific application of enzymes in whole wheat bread to increase loaf volume and decrease initial crumb hardness and bread staling. PRACTICAL APPLICATION: This study will provide guidance for practical uses of enzymes in improving whole wheat dough and bread quality.

Wheat germ agglutinin is a biomarker of whole grain content in wheat flour and pasta

When consumed as whole grain, wheat has a high nutrient density that contributes to a healthy diet. Yet, products labeled as whole wheat can still contain a substantial amount of refined grain leading to the confusion for consumers, so a method was designed to determine the whole grain status within wheat-based foods. Wheat germ agglutinin (WGA), a lectin found in the germ tissue of wheat kernels, was evaluated as a biomarker of whole grain wheat. WGA content strongly correlated with the percentage of whole wheat within premade mixtures of whole and refined (white) flours. Then, commercial flours labeled as whole wheat were tested for WGA content and found to contain up to 40% less WGA compared to a whole grain standard. Commercial pasta products labeled as whole wheat were also tested for WGA content and found to contain up to 90% less WGA compared to a whole grain standard. The differences in WGA content were not likely due to varietal differences alone, as the WGA content in common varieties used in domestic wheat flour production varied less than 25%. The levels of other constituents in wheat kernels, including starch, mineral, phytate, and total protein, were not different among the commercial whole wheat flours and pasta products. WGA is a unique biomarker that can identify wheat products with the highest whole grain content. PRACTICAL ABSTRACT: Whole grain wheat has a high nutrient density that can be part of a healthy diet, but products labeled as whole wheat can still contain some refined grain. Wheat germ agglutinin (WGA) was tested as a biomarker to measure whole grain status in wheat-based foods and revealed that some commercial whole wheat flour and pasta contained unexpectedly lower levels of the WGA biomarker compared to a whole grain standard. WGA may therefore be a useful way to test for whole grain wheat content.

Reducing Visual Differences in Whole Grain Bread Prepared with Hard Red and Hard White Wheat: Application for Sensory Studies

Consumer taste preference can be influenced by visual preference. To eliminate the influence of visual preference in the sensory evaluation of whole grain wheat, a reproducible method to eliminate color differences between Whole Grain breads prepared from hard white wheat (HWW) and hard red wheat (HRW) was evaluated. Response surface methodology (RSM) was used to match the color of HWW to HRW with the addition of commercially available dye solutions: McCormick black (red #40, yellow #5, blue #1), red (red #40, red #3, yellow #6), and yellow (yellow #5). Bread color was assessed by L^* , a^* , and b^* color parameters according to the CIELAB international system of color measurement. Four replicates of the control and dye treated breads were analyzed. Initial color values for HRW were L^* = 56.8 ± 0.40; a^* = 8.04 ± 0.44; b^* = 21.34 ± 0.46. RSM was used to predict dye addition levels to match color between HWW and HRW. With the addition of black (0.457 µL/mL), red (0.574 µL/mL), and yellow (1.165 µL/mL) dye to HWW, breads could be produced with L^* , a^* , and b^* values of no statistical difference to the HRW (P < 0.05). A timed storage trail demonstrated the need to standardize the time between bread production and feeding studies. Visual bias can hinder assessment of wheat varieties in sensory studies. A reproducible method of dying wheat was developed that can be used to reduce this bias in sensory studies. PRACTICAL APPLICATIONS: The ability to control color variability is a critical tool in determining perceived quality in sensory analysis of breads. In this study, a method to reduce or eliminate visual bias between breads made from different varieties of wheat was developed. This method is applicable to any foods where dye could be added to reduce or eliminate color bias in sensory studies.

Comparison of the Aroma Profiles of Intermediate Wheatgrass and Wheat Bread Crusts

The aroma profiles of bread crusts made from intermediate wheatgrass (Thinopyrum intermedium) and whole wheat (Triticum aestivum) flours were compared. Based on gas chromatography/mass spectrometry/olfactometry analysis, twenty-four odorants were identified and further quantified. The concentrations of seventeen compounds were significantly different between intermediate wheatgrass and whole wheat bread crusts, of which sixteen compounds were higher in the whole wheat sample. The aroma profiles of the bread samples were subsequently characterized using sensory descriptive analysis (DA) and indicated that the roasted attribute was perceived at a significantly higher intensity in the whole wheat sample due to a greater amount of Maillard reaction compounds. Alternatively, bran and green notes were perceived at higher intensities in the intermediate wheatgrass sample, however they were not attributed to the presence of specific compounds but rather to a change in the aroma composition. Aroma recombination DA of the whole wheat and intermediate wheatgrass aroma models was similar to the original aroma profiles of the bread samples, demonstrating the sensory relevance of the identified odorants.

Effects of choice feeding and lower ambient temperature on feed intake, growth, foot health, and panting of fast- and slow-growing broiler strains

Effects of lowering ambient temperature in the second half of the growth period were studied in 2 broiler strains with different genetic potential for growth (Ross from 1972 and 2004) when given ad libitum access or pre-mixed increasing proportion of whole wheat in their diet. A total of 48 groups of day-old broilers (n = 64) from the 2 strains were housed as hatched in 48 pens in 4 houses and slaughtered at 6 wk of age. Half of the groups had access to pelleted feed pre-mixed with increasing proportion of whole wheat, the other half had access to pelleted feed and whole wheat in separate troughs. Ambient temperature from 28 d of age was either 21 or 15°C. The fast-growing strain had greater (P < 0.001) live weight throughout (mean slaughter weights 2.6 (±0.014) kg and 1.0 (±0.006) kg). When given a choice, the fast-growing strain consumed a lower (P ≤ 0.004) proportion of whole wheat in their diet in weeks 5 and 6 (20 and 26 (±0.9) % whole wheat), and the slow-growing strain chose a higher (P < 0.001) wheat proportion (45 and 56 (±1.7) %) than the pre-mixed inclusion of 25 and 30%, respectively. The slow-growing strain grew slightly faster in the colder ambient temperature, and slower when given a free choice of whole wheat. Both strains drank more water per feed consumed in the warmer ambient temperature treatment. Foot pad dermatitis, only seen in the fast-growing birds, had a higher occurrence in the colder and in the choice feeding treatments. Gait scoring on day 34 showed perfect gait in more than 85% of the slow-growing and less than 1% of the fast-growing birds. Activity was higher and panting levels were lower in the slow-growing strain (P < 0.001) toward the end of the growth period, with no effect of the temperature treatment on panting. Slow-growing strains increase their energy intake, and fast-growing strains increase their protein intake when given a choice.

The Effects of Moderate Whole Grain Consumption on Fasting Glucose and Lipids, Gastrointestinal Symptoms, and Microbiota

This study was designed to determine if providing wheat, corn, and rice as whole (WG) or refined grains (RG) under free-living conditions will change parameters of health over a six-week intervention in healthy, habitual non-WG consumers. Measurements of body composition, fecal microbiota, fasting blood glucose, total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), and triglycerides were made at baseline and post intervention. Subjects were given adequate servings of either WG or RG products based on their caloric need and asked to keep records of grain consumption, bowel movements, and GI symptoms weekly. After six weeks, subjects repeated baseline testing. Significant decreases in total, LDL, and non-HDL cholesterol were seen after the WG treatments but were not observed in the RG treatment. During Week 6, bowel movement frequency increased with increased WG consumption. No significant differences in microbiota were seen between baseline and post intervention, although, abundance of order Erysipelotrichales increased in RG subjects who ate more than 50% of the RG market basket products. Increasing consumption of WGs can alter parameters of health, but more research is needed to better elucidate the relationship between the amount consumed and the health-related outcome.

Factors affecting the incidence of necrotic enteritis, caecal carriage of Clostridium perfringens and bird performance in broiler chicks

Two trials were conducted to study the effects of a competitive exclusion (CE) product BROILACT and the anticoccidial narasin on the incidence of necrotic enteritis (NE), the numbers of Clostridium perfringens (CP) in the caeca of broiler chicks and the performance of the birds. In trial 1 the effects of type of protein and partial replacement of a narasin containing diet with whole wheat were also studied. All groups of chicks were studied up to the point of slaughter at 43 days of age and after evisceration in a processing plant to determine slaughter yield. In trial 1, statistically significant results included the following: CE-treatment reduced total mortality, and incidence of NE, on diet containing animal but not vegetable protein. Caecal carriage of CP was also reduced, while slaughter yield increased. Narasin reduced caecal carriage of CP and increased both growth rate and slaughter yield in both trials. Whole wheat replacement improved feed conversion but reduced bird growth rate. In trial 2, both CE-treatment and narasin influenced feed intake, CE-treatment significantly only at days 22 and 44. Narasin improved feed conversion until 5 weeks of age and CE-treatment did so until 22 days of age. In both trials, there was also an interaction effect indicating that CE-treatment increased slaughter yield for birds that were not fed narasin.