DEVELOPMENT OF LOW-CARB PREBIOTIC CEREAL BARS USING MICROFLUIDIZED OAT BRAN

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: OTHER GRANTS
• Reporting Frequency: Annual
• Accession No.: 1021763
• Grant No.: 2020-38821-31117
• Cumulative Award Amt.: $299,980.00
• Proposal No.: 2019-03364
• Project Start Date: Apr 15, 2020
• Project End Date: Apr 14, 2025
• Grant Year: 2020
• Program Code: [EQ]- Research Project

Recipient Organization
NORTH CAROLINA A&T STATE UNIV
1601 EAST MARKET STREET
GREENSBORO,NC 27411

Performing Department
(N/A)

Non Technical Summary
Cereal bars are becoming increasingly popular as ready-to-eat snacks. Binders for traditional cereal bars contain large amounts of sugars and sugar syrups. Therefore, replacing these high-calorie cereal bars with a new generation of products that are nutrient-dense, low-calorie, low-fat, and low-sugar will have a tremendous impact on population health. For this reason, this project proposes an innovative process to develop low-carb prebiotic cereal bars using microfluidized oat bran as a novel binder. Oat bran will be microfluidized and rheological and physicochemical properties of microfluidized oat bran will be characterized. Using the microfluidized oat bran as a binder, low-calorie common and low-carb prebiotic (containing whole grains) cereal bars will be developed. Proximate composition, caloric content, beta-glucan content and molecular weight, and microstructure and texture of the cereal bars will be measured, and sensory evaluation will also be conducted. Finally, gut microbiota-modulating effects of the cereal bars will be evaluated.

Animal Health Component

40%

Research Effort Categories

Basic

60%

Applied

40%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
502	1599	1010	30%
502	1560	2020	40%
502	1219	2020	15%
502	1599	2020	15%

Knowledge Area
502 - New and Improved Food Products;

Subject Of Investigation
1560 - Oats; 1599 - Grain crops, general/other; 1219 - Edible tree nuts, general/other;

Field Of Science
2020 - Engineering; 1010 - Nutrition and metabolism;

Keywords

microfluidization

oat bran

cereal bars

prebiotic

low-carb

Goals / Objectives
The goal of the proposed project is to develop low-calorie common and low-carb prebiotic cereal bars using microfluidized oat bran as a novel binder. It will be realized by achieving the following objectives. Objective 1: Prepare and characterize microfluidized oat bran. Objective 2: Develop low-calorie common and low-carb prebiotic cereal bars. Objective 3: Characterize physicochemical properties of cereal bars. Objective 4: Evaluate gut microbiota-modulating effects of low-carb prebiotic cereal bars.

Project Methods
Two Ph.D. students will conduct the proposed research. To track the project progress, weekly meetings and four-month progress reports will be scheduled.Objective 1: Prepare and characterize microfluidized oat bran.1.1. Microfluidization treatment of oat bran An aqueous suspension of 30% (wt/wt) oat bran will be pretreated by using an M-110P Microfluidizer Processor (Microfluidics, Newton, MA, USA) through a 300 µm (IC300) interaction chamber for one pass. The pretreated suspension will be further processed by using an IC200 or IC87 for one pass at three pressure levels: 137.9 MPa (20,000 psi), 172.4 MPa (25,000 psi), and 206.8 MPa (30,000 psi), respectively. The obtained six fresh oat bran pastes will be used to prepare cereal bars.1.2. Physicochemical characterization of microfluidized oat bran The average particle size and particle size distribution of microfluidized oat bran will be assessed by a laser particle size analyzer (Microtrac, Montgomeryville, PA). Microstructure of oat bran will be analyzed by fluorescence microscopy and confocal laser scanning microscopy (CLSM). Water holding capacity (WHC), swelling capacity (SC), and oil holding capacity (OHC) will be measured according to our published methods.1.3. Measurement of rheological properties of microfluidized oat bran The rheological properties including viscoelasticity and viscosity of microfluidized oat bran will be measured using a Discovery HR-3 rheometer (TA Instruments, New Castle, DE).Objectives 2: Develop low-calorie common and low-carb prebiotic cereal bars. 2.1. Formulation of low-calorie common cereal bars Different amount of microfluidized oat bran will be used to partially or totally substitute traditional binding syrup (glucose syrup, fructose syrup, brown sugar, glycerol, and honey). Four substitution levels, i.e., 40%, 60%, 80%, and 100%, respectively, will be tested. The weight ratio of binding agents to dry particulate ingredients will be optimized. Particulate dry ingredients will include toasted puffed rice, rolled oats, corn flakes, chopped nuts, coconut flakes, etc.2.2. Formulation of low-carb prebiotic cereal bars Particulate dry ingredients will be carefully selected from high fiber whole grains including whole grains from oats (rolled or puffed), puffed brown rice, millet, quinoa, amaranth, and buckwheat. Chopped nuts, coconut flakes, chia seeds may also be included in order to achieve desired flavor or better nutritional value. The ratio of binding agents to dry ingredients, insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) will be optimized and their impact on gut microbiota-modulating effects of formulated cereal bars will be evaluated.Objectives 3: Characterize physicochemical properties of cereal bars. 3.1. Measurement of proximate composition, water activity, and caloric content The chemical composition (moisture, lipids, proteins, and ash) of cereal bars will be determined according to the AOAC standard methods. Total dietary fiber (TDF), IDF and SDF contents will be quantified by the AOAC Official Method 2011.25 using a commercial assay kit (K-INTDF) (Megazyme International, Wicklow, Ireland). Water activity will be measured using a thermoconstanter (TH-200, Novasina, Lachen, Switzerland). Caloric content (kcal/100g) of cereal bars is calculated using the nutrient database software (Food Processor 8.6.0, ESHA Research, Professional Nutrition Analysis Software and Databases, Salem, OR, USA).3.2. Evaluation of the content and molecular weight of β-glucan Totalβ-glucan,water-extractable β-glucan content, and un-extractable β-glucan in cereal bars will be determined using the mixed-linkage (1→3), (1→4) β-D-glucan assay kit (Megazyme Ltd., Co., Wicklow, Ireland) following the AACC standard Method 32-23. Molecular weight of the β-glucans will be determined using a high performance size exclusion chromatography (HPSEC) system.3.3. Measurement of microstructure of cereal bars Microstructure of cereal bars will be analyzed by SEM and confocal laser scanning microscopy (CLSM). For visualization the distribution of the major components and their compatibility in cereal bars by CLSM, bar sections will be stained by three dyes: fluorescent brightener 28 or immunolabeling for β-glucan, rhodamine B for protein and FITC for starch.3.4. Analysis of textural properties Texture profile analysis (TPA) including crispiness, hardness, and breaking force will be performed at room temperature using a TA-XT2 Texture Analyzer (Stable Micro Systems, Haslemeres, England). The double compression test will be carried out with an HDP/BSK stainless steel blade. The blade will be aligned perpendicular to the length of the bars and tested successively from side to side. Three cereal bars per formulation will be tested at 2 cm from each edge lengthwise, and in the middle (nine measures per formulation).3.5. Sensory evaluation Cereal bar samples will be evaluated by a consumer panel (n=30) for acceptability using a 9-point hedonic scale (9 = like extremely, 5 = neither like nor dislike, 1 = dislike extremely). Overall acceptance, appearance, texture and taste will be evaluated. A value of 6.0 (like slightly) on the 9-point hedonic scale will be considered the minimum acceptability level.3.6. Surface color measurement A color meter (CM- 700d, Minolta, Osaka, Japan) will be used to determine surface color of cereal bars.Objective 4: Evaluate gut microbiota-modulating effects of cereal bars. 4.1. Assessment of prebiotic activity In vitro batch digestion and fermentation of prebiotic cereal bar samples will be conducted to assess their ability to modify the number and community composition of intestinal microbiota. Prior to in vitro fermentation in human fecal samples, cereal bar samples will be digested using a two-stage digestive model system that simulates the gastric and small intestinal phases. The changes in microbial community will be characterized by a combination of microbiological analyses including quantitative PCR (qPCR), PCR-denaturing gradient gel electrophoresis (DGGE), and high-throughput 16S rRNA gene-based pyrosequencing analysis. The bacterial DNA will be isolated from each fermentation aliquot using QIAamp DNA Microbiome Kit (QIAGEN, USA), as per the manufacturer's instructions. Bacterial numbers will be quantified by qPCR (Mastercycler Pro PCR System with vapo.protect, Eppendorf of North America, NY, USA) using the extracted DNA with the primers for Bifidobacterium, Bacteroides fragilis group, Blautia coccoides group, and total bacteria. The microbial community composition will be determined by DGGE (DCode™ system for DGGE, Bio?RadLaboratories, Hercules,CA,USA) and 16S rDNA based pyrosequencing (3500xL Genetic Analyzer, ThermoFisher Scientific, MA, USA).4.2. Quantification of fermentation metabolites The concentrations of short chain fatty acids (SCFA) in fecal slurry collected from Section 4.1 will be determined using a well-established method. At each fermentation time point, 2-ethylbutyric acid in 2 M sodium hydroxide will be added to fermentation slurry as an internal standard and stored at -80 °C. SCFAs will be extracted from the samples with diethylether and the concentrations of major SCFAs will be measured by gas chromatography (Agilent 7890A Gas Chromatograph coupled to an Agilent 5975C Mass spectrometer, Agilent Technologies, CA, USA).Statistical analysis Data in triplicate will be analyzed by one-way analysis of variance using the Statistical Analysis System (SAS Institute, Cary, NC, USA). Evaluations will be based on a significance level of P < 0.05.

Progress 04/15/23 to 04/14/24

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?For the next reporting period wi will focus on the evaluation ofgut microbiota-modulating effects of low-carb prebiotic cereal bars.

Impacts
What was accomplished under these goals? Innovative process to develop novel binder for cereal bars One of the most critical and challenging tasks of the project is to reduce or completely eliminate sugars and sugar syrups in the binders of cereal bars. Based on the results from last year, a healthier and all-natural binder was reformulated by optimizing the ratio of oat bran, chia seeds and 40% Beta-Glucan. These binder components are inherently very high in dietary fiber and low in net carbs. In addition, chia seeds have gained popularity as asuperfood. They are the richestvegan sourcesforomega-3 fatty acids. Microfluidization process wasusedtofurther modify the rheological properties of oat bran and a very viscous paste could be produced. Therefore, this novel binder exhibited strong binding ability to hold the dry particulate ingredients together. At the same time, it did not interfere with the flavor, texture, and appearance of final products. By using this healthy binder, low-calorie prebiotic cereal bars were purposefully crafted with an ideal mix of protein, fat, carbohydrates and dietary fiber. More importantly, dietary fiber in puffedwholegrains is mainly insoluble fiber, whereas binder contains highlevels of soluble fiber. The binder provides additional nutritional and health benefits to the final products. The formulatedcereal bars had well-balanced nutritional profilewhich is perfect for breakfast-on-the-go. Rheological properties of optimized microfluidized oat bran and chia seeds mixtures The rheology of the optimized binder was analyzed using a Discovery Hybrid Rheometer-3 equipped with a standard Peltier concentric cylinder geometry (TA Instruments, New Castle, DE) at 25°C. Table 1 presents the apparent viscosity comparison between the OBP binder and the optimized binder with beta-glucan at various shear rates. The apparent viscosity of the beta-glucan enriched binder increased significantly from 7.06 Pa·s to 94.69 Pa·s. This higher viscosity resulted in a stronger binding capability, thereby producing more robust cereal bars. Notably, the optimization with beta-glucan enhanced the binder's efficiency without compromising the texture of the bars. The dry particulate ingredients were less likely to crumble, while the overall hardness of the bars did not show a significant increase. Table 1. Apparent viscosity (Pa.s) of optimized binders at different shear rate (1/s) at 25 C Shear rate (1/s) Viscosity (Pa.s) OBP binder OBP- beta glucan binder 1 7.06 94.69 2 6.01 71.14 3 4.80 55.03 5 3.59 42.55 8 2.66 32.50 12 2.00 24.26 19 1.50 16.67 31 1.10 11.17 49 0.80 7.53 77 0.54 4.61 122 0.40 2.53 193 0.30 1.30 306 0.23 0.80 485 0.18 0.51 769 0.14 0.32 1219 0.11 0.14 Shelf-life study of low-carb cereal bars The shelf-life of the cereal bars prepared with the optimized binder was assessed over a period of four weeks. Sensory qualities, including textural properties and microbial shelf-life, were recorded. Table 2 provides data on hardness, brittleness, toughness, and water activity of the bars throughout the study. An ANOVA analysis indicated that the changes in textural properties and water activity were not statistically significant over the study period. Similarly, as presented in Table 3, the microbial shelf-life study showed no statistically significant differences in microbial growth, indicating that the low water activity of the cereal bars effectively inhibited microbial proliferation. The optimized binder not only enhances the nutritional profile of the bars by adding valuable dietary fiber and omega-3 fatty acids but also preserves the overall texture and quality. Importantly, it does not increase the bars' propensity to absorb moisture during storage, thus maintaining their crispiness over extended periods. This discovery represents a significant advancement in cereal bar formulation, offering a healthier and more stable product for consumers. Maintaining low water activity is crucial in preserving the sensory attributes of the cereal bars. Low water activity helps keep the bars' texture, flavor, and overall quality intact, preventing undesirable changes such as staleness or a rubbery texture. This ensures that the cereal bars remain appealing and enjoyable for consumers throughout their shelf life, providing a consistently high-quality, nutrient-dense, high-fiber snack option with minimal risk of spoilage. Table 2. Textural properties and water activity of the cereal bars during 4 weeks Brittleness (mm) Hardness (g) Toughness (g/mm) Water activity Week 0 0.495±0.01 654.15±45.59 1264.81±100.81 0.33±0.01 Week 1 0.55±0.35 596.065±155.81 1165.4±449.06 0.385±0.01 Week 2 0.57±0.08 417.725±90.74 700.805±265.65 0.37±0.00 Week 3 0.545±0.06 592.45±29.22 1038.24±67.60 0.37±0.03 Week 4 0.615±0.11 428.715±6.36 660.9±119.11 0.35±0.00 Table 3. Colony forming units per milliliter of the cereal bars during a 4 week period log10(CFU/mL) Week 0 0.778151±0.143778 Week 1 0.744725±0.087376 Week 2 0.877595±0.082038 Week 3 0.714783±0.110148 Week 4 0.74177±0.1518 Nutritional profile of cereal bars Table 4 shows a comparison between the reformulated low-calorie prebiotic cereal bars and three commercial bars. The main differences between our high-fiber bars and the commercial ones were the sugar content and the dietary fiber content. Table 4. Nutritional profile comparison between OBP bars and commercial bars per 100 g total total total total dietary protein calories fat carbohydrate sugars fiber OBP cereal bars (without nuts) 317.9 6.5 72.3 2.3 36.5 10.0 OBP cereal bars (with nuts) 353.0 12.3 66.9 2.4 33.1 10.7 Commercial bar 1 440.0 20.0 58.0 18.0 6.0 10.0 Commercial bar 2 452.4 16.7 69.0 28.6 4.8 7.1 Commercial bar 3 452.4 16.7 69.0 26.2 4.8 7.1 Commercial bar 1: KIND Breakfast Bars, Peanut Butter Commercial bar 2: Nature Valley Granola Bar Maple Brown Sugar Commercial bar 3: Nature Valley Granola Bars Oats 'n Honey The maker of some commercial cereal bars claims thatthey are made from whole grain oats and are an excellent source of whole grains. However, the nutrition facts labelshows that certain products contain12gramsofsugar per serving (42 g), Nearly half of the added-sugar limit per day according to AHA recommendations. In contrast, our formulated bar basically contains no sugar or sugar syrup, having only 2.3-2.4 g of sugar compared to the 18.0-28.6 g of sugar present in the commercial bars. These minimal amounts of sugars present in the formulated bars were naturallyoccurringsugars from whole grains and cereal bran. After the reformulation of the high-fiber cereal bars, the dietary fiber content could reach 33.1-36.5 g/100 g, while the commercial bars only had 4.8-6.0 g/100 g. Basedon atypicalservingsize of 42 g, one high-fiber cereal bar could provide more than half the recommended daily dietary fiber intake, being a much healthier alternative for consumers.

Publications

Progress 04/15/22 to 04/14/23

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We plan to finish objective4by testing the gut microbiota modulating effects of cereal bars prepared with 4 g of a mix of microfluidized oat bran and chia at a 3:1 ratio (wt/wt).

Impacts
What was accomplished under these goals? 1.Rheological properties of microfluidized oat bran paste (OBP) and chia seeds mixtures The OBP concentration chosen for these tests was 20% (wt/wt). Microfluidized OBP was mixed with ground chia seeds at 1:1 (OBPC11), 2:1(OBPC21), 3:1 (OBPC31), and 5:1 (OBPC51) ratios (OBP:chia). The rheology of the mixed pastes and the oat bran and chia controls was studied using a Discovery Hybrid Rheometer-3 with a standard Peltier concentric cylinder geometry and a starch pasting cell (TA instrument, New Castle, DE) at 25 C. 1.1Viscosity of OBP and chia mixtures Table 1 shows the viscosity profile of the pastes at different shear rates. The viscosity of the OBP increased from 3.42 Pa.s to 18.43, 58.95, 42.63, and 44.60 Pa.s when mixed with ground chia seeds at 5:1, 3:1, 2:1, and 1:1 ratios (wt/wt) respectively. A 3:1 ratio (OBPC31) was the optimum ratio among all mixes with the highest viscosity among all mixed pastes at the beginning of the test and the best gel stability at faster shear rates. The chia paste control had the largest viscosity of all samples at the beginning of the test, however the gel was very susceptible to faster shear rates, leading to an acute decrease of the viscosity in the first few points. Table 1. Apparent viscosity (Pa.s) of oat bran and chia pastes at different shear rates (1/s) at 25 C Shear rate OBP OBPC51 OBPC31 OBPC21 OBPC11 Chia 1.99999 3.4235 18.4348 58.9509 42.6297 44.6049 98.0643 3.16973 2.95436 12.4039 40.1142 26.2949 27.8687 80.694 5.02368 2.53309 9.00969 28.2155 17.9448 18.4903 58.199 7.96199 2.16601 6.75364 20.0047 12.72 13.2386 42.4048 12.6189 1.84745 5.14902 14.162 9.86637 9.8827 27.5577 19.9995 1.56927 3.99454 9.9502 7.00982 6.95335 17.6132 31.6973 1.32688 3.12626 7.23724 5.17321 4.81025 8.15426 50.2366 1.11539 2.47671 5.36475 3.87969 3.58813 4.05786 79.6195 0.955437 1.92414 3.97808 2.89791 2.69456 2.99218 126.189 0.803148 1.49095 2.92671 2.14527 2.03048 2.10864 199.996 0.678274 1.15519 2.1417 1.6183 1.53475 1.44277 316.972 0.571011 0.899562 1.59025 1.23154 1.16376 0.95062 502.368 0.471383 0.703624 1.20606 0.944029 0.903074 1.07269 796.201 0.378346 0.549442 0.949798 0.726727 0.711286 0.622361 1261.89 0.299132 0.422844 0.726691 0.532084 0.508704 0.481792 1999.98 0.224901 0.319206 0.535344 0.37955 0.35009 0.340154 1.2Pasting of OBP and chia mixed pastes The pasting study of the samples was carried out in a starch pasting cell. The experiment started at 50 C and the temperature increased at 5 C/min until it reached 95 C, the samples were maintained at 95 C for 300 s. After the temperature hold, the temperature decreased back to 50 C.The highest viscosity of 10.49 Pa.s was recorded for OBP, followed by OBPC51, chia, OBPC31, OBPC21, and OBPC11 with 6.73 Pa.s, 5.78 Pa.s, 5.50 Pa.s, 5.06 Pa.s, and 4.43 Pa.s, respectively. All viscosities reached the highest point at the starch gelatinization temperature except the chia control, which had its highest viscosity at the beginning of the pasting process. The chia gel was susceptible to heat and it lost the structure as the temperature increased. The pasting behavior of the samples suggested the viscosity was closely related to the amount of starch present in the mixtures and that gelatinized starch could play an important role in binders made with microfluidized oat bran. 1.3Viscosity of cooked OBP and chia mixtures The pasting behavior of the samples made evident that pre-cooking the pastes to gelatinize the starch could increase their viscosity and therefore their binding capacity. The samples were cooked 10 minand the viscosity analysis was carried out after the pastes cooled down to room temperature. Table 2 shows the viscosity of each cooked sample at different shear rates. All samples showed a significant increase in their viscosities after cooking. OBPC31 exhibited the highest viscosity (305.33 Pa.s), therefore it was the chosen binder ratio and procedure to prepare the cereal bars. Table 2. Apparent viscosity (Pa.s) of cooked oat bran and chia pastes at different shear rates (1/s) at 25 C Shear rate OBP OBPC51 OBPC31 OBPC21 OBPC11 Chia 2.00023 278.991 161.623 305.329 246.475 225.605 122.627 3.16979 183.445 112.005 201.011 157.461 150.027 104.028 5.02373 130.251 81.9162 141.797 109.042 89.8676 82.9064 7.96204 95.1588 61.3558 97.8927 75.1214 62.5605 57.5157 12.6191 69.8782 46.9745 67.4384 54.2372 42.9711 36.8078 19.9995 51.6259 36.061 47.0433 37.1872 26.8809 21.3834 31.6973 35.3077 27.632 33.4834 28.356 20.9835 14.5753 50.2371 23.0724 20.9163 23.8547 20.5975 14.9434 9.68075 79.6204 14.8546 15.2114 16.7775 14.6943 11.2077 5.7626 126.19 9.59502 10.9288 11.5686 10.2876 7.813 3.88163 199.997 5.87153 7.729 7.79968 7.15999 5.43648 2.7004 316.974 3.72358 4.92556 5.1464 4.84426 3.76451 1.84244 502.361 3.23521 3.23657 3.07523 3.19836 2.51164 1.52057 796.213 2.51168 1.66002 2.03319 1.2747 1.6827 0.667356 1261.88 1.82655 0.541354 1.36468 0.321305 0.755332 0.567496 1999.93 1.59383 0.171742 0.899479 0.03297 0.186549 0.545022 2.Texture analysis of cereal bars Table 3 shows the effect of different amounts of binder on hardness, brittleness, and toughness of the cereal bars prepared in the laboratory and one commercial bar. Three-point bend tests were carried out using a TA.XT.Plus Texture Analyzer (Stable Micro System, Ltd, Hamilton, MA) with a TA-42 Knife blade with 45 angle chisel end attachment. The hardness of the bars decreased from 3454.0 g using 6 g of binder to 393.8 g using 2 g of binder. The commercial bar presented a hardness of 2724.9 g. The brittleness measured the distance the blade could travel before fracture. The bars prepared with 4 and 3 g of binder showed 1.1 and 1.4 mm of brittleness respectively, even more than the commercial bar which had 0.6 mm. However, the hardness of the bar prepared with 3 g of binder was too low so the bar was weak and easy to break. 4 g of binder was the chosen amount to prepare the cereal bars. Table 3. Textural properties of cereal bars prepared with different binding agent amounts. Bar ID Hardness (g) Brittleness/Flexibility (mm) OBPC31 - 6 g of binder 3454.0±338.0 0.8±0.2 OBPC31 - 5 g of binder 2024.1±592.5 0.8±0.2 OBPC31 - 4 g of binder 1608.0±459.0 1.1±0.6 OBPC31 - 3 g of binder 693.3±17.1 1.4±1.0 OBPC31 - 2 g of binder 393.8±213.6 0.5±0.1 Commercial bar 1 2724.9±395.1 0.6±0.1 3.Nutritional profile of cereal bars The cereal bars were prepared using 4 g of the OBPC31 binder. Table 4 shows a comparison between the optimized cereal bars prepared in the laboratory, and two commercial types. The main differences between the laboratory bars and the commercial ones were the sugar content and the dietary fiber content. Laboratory bars had 1-1.2 g of sugar compared to the 28.6-17.1 g of sugar present in the commercial bars. The only sugars present in the laboratory bars were natural sugars, without added sugars. Laboratory bars also had 30.7-27.5 g of dietary fiber, a significantly higher amount compared to the commercial bars that only had 4.8-5.7 g. The average serving size of cereal bars is 42 g; therefore, the laboratory cereal bars could provide almost the daily 25 g of dietary fiber recommended, being a much healthier alternative for consumers. Table 4. Nutritional profile comparison between OBPC31 bars and commercial bars per 100 g OBPC31 Barwithout nutsOBPC31 Barwith nuts Commercial bar 1 Commercial bar 2 Total Calories (g) 318.4 362.4 452.4 428.6 Total fat (g) 6.8 14.2 16.7 14.3 Total carbohydrate (g) 75.9 68.5 69.0 65.7 Total sugars (g) 1.0 1.2 28.6 17.1 Dietary fiber (g) 30.7 27.5 4.8 5.7 Protein (g) 9.0 9.8 7.1 8.6

Publications

Progress 04/15/21 to 04/14/22

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We plan to finish objectives 2 and 3 bytesting OBP made with 30% dispersions and finish objective 4.

Impacts
What was accomplished under these goals? OBJECTIVE 1 1. Preparation of microfluidized oat bran Based on previous results, the oat bran processing conditions changed to produce higher viscosity oat bran pastes (OBP). Raw oat bran was ground using a S102DS lab grinder until it passed through a US standard No. 5 sieve with a nominal opening of 500 µm. The ground bran was dispersed in deionized water at a 15:85, 20:80, 25:75, and 30:70 bran:water (wt/wt) ratios (15%, 20%, 25%, 30% dispersions respectively).The dispersions soaked for 1 hprior processing. The soaked oat bran was processed througha 300 µm interaction chamber (IC300) for 1, 3, and 5 passes ina M-110P Microfluidizer processor at 25,000 PSI. The fresh OBPs were collected to test the rheologicalproperties. The unused pastes were freeze dried and pulverized to further measure their physicochemical properties (water holding capacity (WHC), oil holding capacity (OHC), swelling capacity (SC), and bulk density (BD)). 2. Rheological behavior of microfluizidized oat bran paste The rheology of an OBP was studied using a Discovery Hybrid Rheometer-3 with a standard Peltier concentric cylinder geometry (TA instrument, New Castle, DE) at 25 C. Table 1shows the changes in apparent viscosity for the different samples at different shear rates. The apparent visosity of 30% disperisons of ground oat bran increased from 0.43 Pa*s12.41 and 9.83 Pa*s after processed through an IC300 for 1 and 3 passes, respectively; for 25% dispersions of ground oat bran, the viscosity increased to 3.68 and 2.64 Pa*s respectively. Table 1. Apparaent Viscosity (Pa.s) of oat bran paste at different shear rate (1/s) at 25 C Shear rate (1/s) 10 20 30 4050 6070 80 90 100 Ground Oat Bran 0.43 0.29 0.24 0.22 0.22 0.21 0.19 0.18 0.17 0.16 15% - IC3001P 0.24 0.18 0.15 0.14 0.13 0.12 0.11 0.10 0.10 0.09 15% - IC3003P 0.17 0.16 0.15 0.14 0.13 0.13 0.13 0.12 0.12 0.11 15% - IC3005P 0.09 0.09 0.09 0.08 0.08 0.08 0.08 0.08 0.08 0.08 20% - IC3001P 0.45 0.38 0.36 0.35 0.32 0.30 0.28 0.27 0.25 0.24 20% - IC3003P 0.53 0.47 0.43 0.40 0.38 0.36 0.35 0.33 0.32 0.31 20% - IC3005P 0.40 0.38 0.35 0.33 0.32 0.30 0.29 0.28 0.27 0.26 25% - IC3001P 3.68 2.31 1.78 1.52 1.33 1.20 1.10 1.05 0.97 0.92 25% - IC3003P 2.64 2.04 1.70 1.51 1.37 1.25 1.17 1.12 1.10 1.04 25% - IC3005P 2.64 2.04 1.70 1.51 1.37 1.25 1.17 1.12 1.10 1.04 30% - IC3001P 12.41 8.28 6.18 5.05 4.31 3.81 3.40 3.14 2.94 2.77 30% - IC3003P 9.83 7.05 5.78 4.98 4.38 3.90 3.53 3.24 3.06 2.95 30% - IC3005P 9.20 6.65 5.55 4.87 4.34 3.93 3.55 3.26 3.01 2.88 3.Hydration properties Bulk Density Bulk density was determined by compressing 5 g of oat branin a 25 ml graduated cylinder. Table 2 shows an overall decrease in the bulk density of the samples from0.91 g/ml in ground oat branto 0.43 g/ml in 15% oatbran samples processed through anIC300 for 3 and 5 passes, and 30% oat bran samples processed through anIC300 for 5 passes. Swelling Capacity The swelling capacity of the oat bran samples was measured by dispersing 0.5 g of oat bran powder into 20 ml of DI water in a 25 ml graduated cylinder and letting it sit for 24 h covered at room temperature. Table 2shows most of the OBP powders increased inthe swelling capacity compared to ground oat bran, 15% oat bran samples processed through an IC300 for 3 passes showed thehighest swelling capacity of 9 ml/g. Water holding capacity Water holding capacity was measured by dispersing 0.5 g of oat bran powder into 20 g of DI water in a 50 ml tube. The dispersion was allowed to hydrate for 24h and was subsequently centrifuged at 350 0g for 10 minutes. The supernatant was carefully removed with a pipette and the tubes were drained upside down for 5 minutes. The weight of the remaining sample was recorded and compared to the weight of the dry sample. Table 2 showsthe WHC increased from 1.10gwater/gdry sampleto 1.70 and 1.72gwater/gdry sample for 25% and 30% oat bran samples, respectively,treated once through an IC300. Oil holding capacity Oil holding capacity was measured following the WHC method but using soybean oil with a density of 0.917 g/ml instead of water.Table 2shows an increase in the OHC from 2.1 goil/gdry sampleto 4.08 goil/gdry samplefor 15% and 20% oat bran samples, respectively, treated through an IC300 for one pass and three passes. Table 2. Hydration properties of freeze dried oat bran pastes packed density (g/ml) swelling capacity (ml/g) WHC gwater/gdry sample OHC goil/gdry sample Ground Oat Bran 0.91 7 1.10 2.10 15% - IC3001P 0.45 8 1.58 4.08 15% - IC3003P 0.43 9 1.54 4.02 15% - IC3005P 0.43 7 1.50 4.00 20% - IC3001P 0.50 8 1.60 3.74 20% - IC3003P 0.48 8 1.44 4.08 20% - IC3005P 0.45 8 1.46 3.42 25% - IC3001P 0.50 7 1.70 3.68 25% - IC3003P 0.48 7 1.56 3.16 25% - IC3005P 0.48 8 1.36 3.02 30% - IC3001P 0.50 7 1.72 3.14 30% - IC3003P 0.45 8 1.66 3.48 30% - IC3005P 0.43 8 1.58 2.98 OBJECTIVE 2 1. Cereal bar composition and preparation The OBP chosenfor these tests was 25% - IC3001P. The cereal bars were prepared mimicking the composition of commercial brands. The composition of one bar was as follows: 7.5 g of rice krispies, 2.5 g of puffed millet, 7.5 g of rolled oats, 1.25 g of puffed amaranth grain, 1.25 g of flaxseeds. The weight of binding agent in the bars ranged from 6.5to 9 g. The composition of the binding agent varied from 100% oat bran and 0% of honey to 100% honey and 0% oat bran paste. All ingredients except the binding agent were first thoroughly mixed, then the binding agent was added and all the ingredients were mixed manually until everything was coated with the binding agent. The mix of grains and binder was manually pressed into a metallic mold to shape it into a bar. Thebars were baked in the mold at 275F for 14minand were tested after cooling to room temperature. 2. Textural properties of prebiotic cereal bars Table 3 shows the results for fracturability and hardness of two commercial cereal bars and the bars prepared in the laboratory.The texture of the bars was tested using a TA.XT.Plus Texture Analyzer (Stable Micro System, Ltd, Hamilton, MA ). A three point bending test was carried out on the prebiotic bars to test their fracturability using a with a TA-42 Knife blade with 45 angle chisel end attachment. The hardness of the bars was tested using 1" cylinder probe attachment. Two commercial cereal bars were also tested as controls. The bar prepared with 6.5 g of OBP did not bind successfully and could not be tested. The fracturability of the laboratorybars was very similar to the fracturability of the commercial bars, being the commercial bars more brittle than the laboratory bars. The composition of the binding agent also affected the fracturability, and bars prepared with just OBP broke slightly faster than those with 50% or 100% of honey. Theamount of binding agent also affected the bars; the bars prepared with just OBP showed an increase resistance to fracture with higher amounts of OBP, whereas bars prepared with a 50/50 mix of honey and OBP as binding agent showed a slight decrease resistance to fracture compared with higher amounts of binding agent. The hardness of the bars prepared in the laboratory was significantly lower than the commercial bars. Bars prepared with just OBP were slightly less hard than those with honey as part of the binding agent. Table 3. Textural properties of cereal bars prepared with different binding agents Binder formulation Fracturability (mm) Hardness (Kg) Commercial bar 1 39.8 18.3 Commercial bar 2 41.3 21.4 6.5 g OBP -- 3.25 honey-3.25 OBP 44.4 2.9 8g OBP 42.5 5.9 4g honey 4g OBP43.9 5.6 8g honey 45.8 7.9

Publications

Progress 04/15/20 to 04/14/21

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We plan to proceed to the objective 2 and 3 during the next reporting period.

Impacts
What was accomplished under these goals? 1. Preparation of microfluidized oat bran under different conditions Raw oat bran (Bob's Red Mill Natural Foods, Milwaukie, WI) was repeatedly ground using a S102DS lab grinder (Strand Manufacturing Co., MN) until passing through a US standard No. 35 sieve with a nominal opening of 500 um (Fisher Scientific Co. TX, USA). The ground bran was dispersed in deionized water (bran:water=25:75, wt/wt) and soaked for one hour before processing through a 300 μm interaction chamber (IC300), an IC200 and an IC87 of an M-110P Microfluidizier Processor (Microfluidics, Newton, MA, USA) at its allowable or achieveable (depending on the chamber size)highest processing pressure and room temperature for 1-3 passes, respectively. The freshly prepared oat bran pastes were used for particle size, rheology, and texture analysis. The rest of the samples were lyophilized, pulverized and storedin the fridge for other physicochemical characterization including microstructure changes, water holding capacity (WHC), swelling capacity (SC), and oil holding capacity (OHC) of oat bran before and after microfluidization treatment. 2. Analysis of particle size distribution and microstructure of microfluidized corn bran The particle size distribution wasmeasured using a computer controlled Bluewave laser particle analyzer (Microtrac, Montgomeryville, PA). Table 1 indicated that the size of the interaction chamber hada more significant effect on the three particle size parameters: mean diameter in microns of the volume distribution (MV), mean diameter in microns of the number distribution (MN), and mean diameter in microns of the area distribution (MA). The microstructure of oat bran was analyzed by both light microscopy and confocal laser scanning microscopy. The results showed that the microfluidization process could effectively reduce the particle size of oat bran and loosen microstructure of the bran matrix. Table 1 Effect of microfluidization chamber size and number of passes on the particle size distribution of oat bran MV(um) MN(um) MA(um) non-treated130.10±3.68 3.09±0.06 12.90±1.70 Ic300 1p 128.85±9.55 2.49±0.04 10.96±0.24 Ic300 2p97.08±6.68 2.45±0.02 9.88±0.30 Ic300 3p 36.10±5.892.56±0.01 7.92±0.21 Ic200 1p12.55±0.472.76±0.00 6.78±0.06 Ic200 2p13.25±1.10 2.57±0.24 6.49±0.07 Ic200 3p 11.04±0.20 1.88±0.136.06±0.12 Ic87 1p 11.22±1.09 2.46±0.76 6.57±0.49 Ic87 2p 10.09±0.332.59±0.84 6.47±0.28 Ic87 3p 9.41±0.28 2.01±0.01 6.19±0.02 3. Effect of microfluidization on the rheological and textural behavior of oat bran paste The rheological behavior of oat bran paste was studied using a Discovery Hybrid Rheometer-3 (DHR3) with a standard Peltier Concentric Cylinder geometry (TA instrument, New Castle, DE) at 25 C. The results in Table 2 showed that the apparent viscosity increased from 1.49 Pa.s to 4.78 Pa.s and 2.65 Pa.s after processing through an IC300 and anIC200 for one pass at shear rate of 10 1/s, respectively, while the viscosity decreased with an increase in the number of processing passes when using the same interaction chamber. Table 2 Apparaent Viscosity (Pa.s)of oat bran paste at different shear rate (1/s) at 25 C Shear rate (1/s) 10 20 30 40 50 60 70 80 90 100 non-treated1.49 0.94 0.70 0.57 0.50 0.45 0.43 0.41 0.39 0.37 Ic300 1p 4.78 2.89 2.18 1.85 1.68 1.491.36 1.27 1.18 1.11 Ic300 2p3.52 2.33 1.83 1.60 1.41 1.28 1.18 1.14 1.08 1.01 Ic300 3p 2.80 1.95 1.57 1.37 1.24 1.14 1.06 1.01 0.96 0.93 Ic200 1p 2.65 1.63 1.30 1.11 0.98 0.89 0.82 0.77 0.72 0.68 Ic200 2p 1.771.16 0.96 0.85 0.77 0.71 0.66 0.62 0.58 0.55 Ic200 3p 1.641.04 0.85 0.74 0.67 0.62 0.57 0.53 0.50 0.48 Ic87 1p 1.49 1.02 0.86 0.76 0.70 0.64 0.60 0.57 0.54 0.51 Ic87 2p 0.96 0.69 0.59 0.53 0.49 0.46 0.43 0.41 0.39 0.38 Ic87 3p 0.92 0.66 0.55 0.49 0.45 0.42 0.40 0.38 0.36 0.35 The adhesive tests were conducted to measure the surface stickiness and stringiness of oat bran paste using a TA.XT.Plus Texture Analyzer (Stable Micro System, Ltd, Hamilton, MA).Ten milliliters of sample was placed in a small beaker centrally under a 1" cylinder probe. The probe applied a force of 0.06 N on the surface of the sample. After holding this force for 2 seconds, the probe withdrew from the sample at 8 mm/s and stopped at 170 mm above the sample surface. The maximum force required to separate the probe from the sample was recorded as the stickiness. The stringiness valuewas recorded as the distance the probe moved away from the sample surface before the force drops to 0.02 N. Table 3 showed that the microfluidization treatment significnatly increased the stinginess of oat bran paste. Table 3 The surface stickiness and stringniess of oat bran paste afterpassingthrough different interaction chambers Mean Max. Force "surface stickiness" (g) Mean Distance to Separation "Stringiness" (mm) non-treated 0.10 1.10 Ic300 1p 0.11 11.67 Ic200 1p 0.11 11.94 Ic87 1p 0.10 11.36 4. Measurement of hydration properties and oil-holding capacity of mcirofluidized oat bran Bulk density, hydration properties (swelling capacity and water-holding capacity) and oil-holding capacity of cereal bran are determined by its chemical composition, microstructure, and particle size. Table 4 shows these properties of oat bran as affected by microfluidization conditions. Table 4 Bulk density, hydration propertiesand oil-holding capacities of microfluidized oat bran afterpassingthrough different interaction chambers Bulk Density(g/ml) SC (ml/g d.w) WHC(g water/g d.w) OHC (g oil/g d.w) non-treated 0.91 3.00 1.45 1.53 Ic300 1p 0.50 3.00 1.40 3.15 Ic200 1p 0.43 2.25 1.32 4.68 Ic87 1p 0.38 3.00 1.32 3.60

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