Dietary fiber from brown rice products.pptx

A presentation about dietary fiber in brown rice foods

1. 03 2.4. Chemical composition of DF samples Table 1. Methods for chemical composition of DF samples

2. 03 2.5. Particle size - The sample particle size was measured by a laser particle size analyzer (Mastersizer 2000; Malvern Instrument Ltd, Malvern, London, UK). - D10, D50 and D90 represented volumes smaller than 10%, 50% and 90% of the particle size, respectively.

3. 03 2.6. Structural analysis of DF samples X-ray diffraction (XRD) X-ray diffractometer (D8 Advance, Bruker, Germany) Target: Cu Kα; wavelength: 0.15406 nm; voltage: 40 kV; current: 40 mA; scanning rate: 5◦/min; scanning range: 3–40◦ (2θ); and scanning mode: continuous. Scanning electron microscopy (SEM) Scanning electron microscope (S–3000N, Hitachi, Co., Ltd., Tokyo, Japan) at 15.0 kV

4. 03 2.7. Physicochemical properties of DF Water-holding capacity (WHC) 0.5 g of DF sample was suspended in 30 mL of water in graduated test tubes and stirred for 4 h. Following centrifugation at 3000 g for 15 min, the residue was weighed (wet weight) and oven-dried at 105 ◦C to constant weight (dry weight). Oil-holding capacity (OHC) Suspend approximately 0.5 g of DF sample in 20 mL of corn oil in a centrifuge tube. The tube was then stirred for 30 s every 5 min, and after 30 min the tubes were centrifuged at 2000 g for 20 min. Swelling capacity (SC) Add 0.3 g dried DF sample to the measuring cylinder and record the original volume. After soaking in 5 mL distilled water and swelling at room temperature for 5 h, record the final volume of swollen fiber

5. 03 3.3. Particle size Particle size distribution of DF plays an important role in physiological functioning of DF The smaller average particle size of DF might lead to a higher binding capacity to water or oil and an adsorption capacity of glucose ( Qiao , Shao , et al., 2021; Song, Su, & Mu, 2018 ) DF from EBR had smaller average particle sizes which indicated that the extrusion process lowered the degree of polymerization of DF ( Qiao , Shao, et al., 2021)  Similar to the study of Wang et al. (2020a), who confirmed that the particles of wheat bran treated with extrusion are smaller while contribute to greater water absorption and expansion.

6. 07 3.4. X-ray diffraction (XRD) Figure. X-ray diffraction patterns of DF extracted from different brown rice products. ( a) X-ray diffraction diagrams of DF The XRD patterns of DF from processed brown rice products were similar, and the main diffraction peaks were 20.1◦ and 22.3◦, respectively. D iffraction peaks of cellulose and hemicellulose usually have 2θ◦ in the range of 15–25 (Dong et al., 2019 ). T he crystal structures of DF samples from brown rice products were cellulose type I, which was the coexistence of crystalline and amorphous regions (Dong et al., 2019) There was no obvious difference in the peak positions for DF samples from cooked BR, GBR and FBR T he crystal structure of the fiber did not change after germination or fermentation treatment. Different diffraction patterns appeared in DF from cooked EBR, and a strong diffraction peak at 30.2◦ This may be caused by the extrusion treatment for the degradation of cellulose and hemicellulose. Extrusion treatment caused the breakage of the molecular chains of cellulose and hemicellulose, which reduced the molecular polymerization and improved the solubility of DF (Wang et al., 2020c).

7. 07 3.4. X-ray diffraction (XRD) Figure. X-ray diffraction patterns of DF extracted from different brown rice products . (b) Crystallinity of DF. Different letters indicated significant difference at P < 0.05 level The crystallinity value of DF from EBR (4.06%) was significantly lower than that of cooked BR (4.99%) (p < 0.05)  R elated to the extrusion destroying hydrogen bonds in the cellulose ( Myat & Ryu , 2014 ) The decrease in crystallinity indicated that the structure of DF from EBR was loosened E xtrusion treatment not only decreased the degree of polymerization of DF from EBR but also might be effective for improving the WHC and OHC (Wang, Wu, Zhang, Kan , & Zheng , 2022)

8. 07 3.5. Scanning electron microscopy (SEM) Figure. Microstructure of (a) BRDF, (b) GBRDF, (c) FBRDF and (d) EBRDF observed by scanning electron micrographs (Magnifications: 1000, respectively). The microstructure of DF from cooked BR and GBR showed a dense surface with some small particles on the surface Compared with cooked BR and GBR, the microstructure of DFs from cooked FBR and EBR had a looser and more porous spatial structure DF from cooked FBR exhibited a structure with a larger number of holes Fermentation removed more starches and proteins around the DF bundles (Chen et al., 2020 ) This result is consistent with the reduction of starch and protein content in DF from cooked FBR shown in Table 1

9. 07 3.5. Scanning electron microscopy (SEM) Figure. Microstructure of (a) BRDF, (b) GBRDF, (c) FBRDF and (d) EBRDF observed by scanning electron micrographs (Magnifications: 1000, respectively). There were much more irregular flaky structures in the DF from EBR than from cooked FBR Due to high temperature and mechanical force during extrusion The destruction of glycosidic bonds and breakage of cellulose or lignin following extrusion, which would increase the surface area of DF ( Qiao , Shao, et al., 2021 ) The loose and porous structure facilitated the hydration and adsorption properties of the DF sample ( Jia et al., 2019; Wang et al., 2020c).  I t was speculated that DF from cooked FBR and EBR own higher WHC, OHC, SC and GAC, especially DF from EBR.

10. 07 3.6. Physicochemical properties - The WHC, OHC and SC of DFs from cooked GBR, FBR and EBR were higher than those of cooked BR (p < 0.05). WHC is an index to evaluate the ability of DF to retain water when subjected to external centrifugal force or compression (Zhang, Wang, et al., 2020 ). The higher WHC can prevent shrinkage and improve the viscosity and texture of some foods. - Compared with cooked BR, the WHC of DFs from cooked GBR, FBR and EBR increased by 3.14%, 26.73% and 44.65%  Due to the specific surface area increased by germination and fermentation greatly enlarged the contact area between DF and water ( Jia et al., 2019).  Extrusion reduce the degree of polymerization of DF, thus increasing the surface area of its particles and exposing more hydrophilic groups  the enhancement of dispersion, the DF particles are conducive to contact with water

11. 07 3.6. Physicochemical properties - The OHC evaluated the ability of DF to bind oil  DF with high OHC value prevents the oil loss in food during cooking and reduces the serum cholesterol level through intestinal absorption of oil - Compared with cooked BR, the OHC of DFs from cooked GBR, FBR and EBR increased by 33.61%, 44.26% and 48.36% (p < 0.05) The increase of specific surface area and the enlargement of DF contact area with oil due to germination and fermentation ( Jia et al., 2019 ) The increase of DF contents in cooked GBR and FBR Extrusion heating might modify the structural characteristics of the fiber  facilitating its oil uptake ( Qiao et al., 2021).

12. 07 3.6. Physicochemical properties - Compared with cooked BR, the SC values of DFs from cooked GBR, FBR and EBR increased by 18.18%, 27.27% and 36.36%, respectively  Due to the architecture of DF has been altered by different processing techniques, resulting in different hydration properties of DF (Liu, Zhang, et al., 2020; Ma et al., 2021). The higher SC of DF from cooked EBR was related to the increase of porosity caused by extrusion  More water molecules are able to interact with the total surface area of DF, leading to an increase in the swelling volume (Wu et al., 2020).

13. 11 IV. Conclusion - The contents of SDF, TPC and TFC in brown rice products were increased by the three processing methods. - DF from EBR had looser and more complicated structures, lower particle size and the crystallinity was significantly reduced - The DF samples from cooked GBR, FBR and EBR performed higher WHC, OHC, SC, antioxidant capacity and GAC than cooked BR, especially the DF from EBR - The changes in physicochemical and functional properties of DF extracted from EBR have been attributed to the more porous surface structure, and the greater exposure to the binding sites of the fiber due to reduced crystallinity Extrusion tends to be a good processing method for brown rice products, with increased antioxidant activity and gastro-intestinal hypoglycemic capacity Recommendation: Conduct comparative studies on the dietary fiber properties of brown rice with other whole grains and cereals Explore the potential application of dietary fiber from processed brown rice products in various food formulations

14. 11 IV. Conclusion Some further research titles for reference