Soluble Dietary Fiber Content Research Articles

Influence of Three Modification Methods on the Structure, Physicochemical, and Functional Properties of Insoluble Dietary Fiber from Rosa roxburghii Tratt Pomace.

Rosa roxburghii Tratt pomace is rich in insoluble dietary fiber (IDF). This study aimed to investigate the influence of three modification methods on Rosa roxburghii Tratt pomace insoluble dietary fiber (RIDF). The three modified RIDFs, named U-RIDF, C-RIDF, and UC-RIDF, were prepared using ultrasound, cellulase, and a combination of ultrasound and cellulase methods, respectively. The structure, physicochemical characteristics, and functional properties of the raw RIDF and modified RIDF were comparatively analyzed. The results showed that all three modification methods, especially the ultrasound-cellulase combination treatment, increased the soluble dietary fiber (SDF) content of RIDF, while also causing a transition in surface morphology from smooth and dense to wrinkled and loose structures. Compared with the raw RIDF, the modified RIDF, particularly UC-RIDF, displayed significantly improved water-holding capacity (WHC), oil-binding capacity (OHC), and swelling capacity (SC), with increases of 12.0%, 84.7%, and 91.3%, respectively. Additionally, UC-RIDF demonstrated the highest nitrite ion adsorption capacity (NIAC), cholesterol adsorption capacity (CAC), and bile salt adsorption capacity (BSAC). In summary, the combination of ultrasound and cellulase treatment proved to be an efficient approach for modifying IDF from RRTP, with the potential for developing a functional food ingredient.

Dietary Fibre Profiling of Various Edible Parts of Winged Bean (Psophocarpus tetragonolobus L.): Pods, Endosperms, Seed Coats, and Cooked Seeds

This study aimed to identify the dietary fibre profiles of various winged bean components (green pods, whole seeds, endosperms, seed coats, and canned whole seeds). Soluble dietary fibre (SDF), insoluble dietary fibre (IDF) (hemicellulose, cellulose, and lignin), total dietary fibre (TDF), and oligosaccharide components (raffinose, stachyose, and verbascose), were analyzed. The Various winged bean components had a higher IDF content than SDF content (21.12-50.11% and 0.83-1.25%, respectively), with the highest TDF content observed in the seed coat (51.81%). Raffinose was the most dominant oligosaccharide component in green pods (2.7 mg/g), while verbascose was the most dominant component in all seed form samples, including seed coats (1.41-3.65 mg/g). The IDF in all samples was dominated by cellulose (5.07-39.34%), followed by hemicellulose (1.5-27.19%), and lignin (0.09-0.98%). Seed dehusking led to significant decreases in all types of dietary fibre analyzed, except for stachyose. Soaking and sterilization processes resulted in an increase in SDF, but decreased IDF, stachyose, verbascose, and hemicellulose compared to raw whole seeds. Principal component analysis (PCA) revealed that raw whole seeds still exhibit similarities in dietary fibre composition with canned seeds, but differ from green pods, endosperms, and seed coats. These findings imply that all edible parts of winged beans offer a large quantity of dietary fibre, especially whole seeds, which have potential benefits as prebiotic sources to improve health.

Comparison of quality, dietary fiber and glycemic index of whole wheat breads using various modern and old wheats and investigate the effect of xylanase

AbstractSix bread wheat varieties (modern wheats) widely grown in Turkey and nine different bread wheat varieties registered prior to 1970 (old wheats) were used in the present study. This study aimed to determine and compare the quality characteristics, dietary fiber contents and in vitro glycemic index of whole wheat breads produced using modern and old bread wheat varieties. The effect of xylanase on the quality, staling and dietary fiber content of whole wheat breads was also investigated. Mean sedimentation and modified sedimentation values, Farinograph development time, stability, quality number of whole wheat flours produced by modern wheats were higher than those of the old varieties. Whole wheat breads of modern varieties had higher mean volume and lower firmness values as compared to old varieties. Whole wheat breads of old wheat varieties had higher mean soluble dietary fiber content as compared to that of modern wheat varieties. Xylanase addition generally had an increasing effect on bread volume and soluble dietary fiber contents and a softening effect on firmness values. There were no significant differences between the mean (in vitro) glycemic index values of whole wheat breads produced from modern and old varieties. The results in the present study indicated that modern bread wheat varieties had better whole wheat bread making quality as compared with old bread wheat varieties. In addition, xylanase usage in whole wheat bread formula had an improving effect on whole wheat bread quality.

Comparison of different drying technologies for kiwifruit pomace: Changes in physical characteristics, nutritional properties and antioxidant capacities

The objective of this study was to evaluate the impacts of different drying technologies including microwave drying (MD), vacuum microwave drying (VMD), sun drying (SD), vacuum drying (VD), hot air drying (HAD), and vacuum freeze drying (VFD) on the physical characteristics, nutritional properties and antioxidant capacities of kiwifruit pomace in order to realize by-product utilization and improve energy efficiency. Results showed that both MD and VMD significantly reduced drying time by >94.6%, compared to traditional thermal drying which took 14–48 h. MD exhibited the highest content of soluble dietary fiber (9.5%) and the lowest energy consumption. Furthermore, VMD resulted in the highest content of vitamin C (198.78 mg/100 g) and reducing sugar (73.78%), and the antioxidant capacities ranked only second to VFD. Given the financial advantages and product quality, VMD was suggested to be advantageous technology in actual industrial production.

Modification of pea dietary fibre by superfine grinding assisted enzymatic modification: Structural, physicochemical, and functional properties

Using the optimal extraction conditions determined by response surface optimisation, the yield of soluble dietary fibre (SDF) modified by superfine grinding combined with enzymatic modification (SE-SDF) was significantly increased from 4.45 % ± 0.21 % (natural pea dietary fibre) to 16.24 % ± 0.09 %. To further analyse the modification mechanism, the effects of three modification methods–superfine grinding (S), enzymatic modification (E), and superfine grinding combined with enzymatic modification (SE)–on the structural, physicochemical, and functional properties of pea SDF were studied. Nuclear magnetic resonance spectroscopy results showed that all four SDFs had α- and β-glycosidic bonds. Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy results showed that the crystal structure of SE-SDF was most severely damaged. The Congo red experimental results showed that none of the four SDFs had a triple-helical structure. Scanning electron microscopy showed that SE-SDF had a looser structure and an obvious honeycomb structure than other SDFs. Thermogravimetric analysis, particle size, and zeta potential results showed that SE-SDF had the highest thermal stability, smallest particle size, and excellent solution stability compared with the other samples. The hydration properties showed that SE-SDF had the best water solubility capacity and water-holding capacity. All three modification methods (S, E, and SE) enhanced the sodium cholate adsorption capacity, cholesterol adsorption capacity, cation exchange capacity, and nitrite ion adsorption capacity of pea SDF. Among them, the SE modification had the greatest effect. This study showed that superfine grinding combined with enzymatic modification can effectively improve the SDF content and the physicochemical and functional properties of pea dietary fibre, which gives pea dietary fibre great application potential in functional foods.

Investigation of the sensory quality, nutritional value and antioxidant capacity of flakes prepared using various pigeon pea-based flours

Pigeon pea (Cajanus cajan (L.)) is a potential source of nutritional and antioxidant compounds. Germination proved to improve the nutritional quality and antioxidant capacity of pigeon peas. The previous author’s study showed that pigeon pea flour prepared by NaCl elicitation before germination exhibits significantly higher antioxidant capacity and functional properties than that prepared without elicitation or germination. The study aimed to examine the sensory quality, nutrition value, and antioxidant capacity of flakes formulated using non-germinated pigeon pea flour, pigeon pea sprout flour, and NaCl-elicited pigeon pea sprout flour. The potential of the flours to be developed as commercial flakes was also determined using oat-based commercial flakes as a comparator. The NaCl-elicited pigeon pea flour-based flakes showed a higher quality score of both texture and overall qualities than the other pigeon pea flour-based flakes and the commercial ones. Regarding nutritional value, flakes formulated using NaCl-elicited pigeon pea sprout flour also showed better nutritional value, indicated by the lowest fat content and highest soluble, insoluble, and total dietary fiber contents. The highest values of total phenolics content (TPC), Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) were also observed in the NaCl-elicited pigeon pea sprout flour-based flakes, even though its DPPH radical scavenging activity was not significantly different to the commercial flakes. These results have significant consequences for developing legume-based flakes with higher levels of dietary fibers and antioxidant potential, and lower fat content.

Fermentation of millet bran with Bacillus natto: enhancement of bioactivity levels and the bioactivity of bran extract.

Millet bran (MB), a byproduct of millet production, is rich in functional components but it is underutilized. In recent years, researchers have shown that fermentation can improve the biological activity of cereals and their byproducts. This study used Bacillus natto to ferment millet bran to improve its added value and broaden the application of MB. The bioactive component content, physicochemical properties, and functional activity of millet bran extract (MBE) from fermented millet bran were determined. After fermentation, the soluble dietary fiber (SDF) content increased by 92.0%, the β-glucan content by 164.4%, the polypeptide content by 111.4%, the polyphenol content by 32.5%, the flavone content by 16.4%, and the total amino acid content by 95.4%. Scanning electron microscopy revealed that the microscopic morphology of MBE changed from complete and dense blocks to loosely porous shapes after fermentation. After fermentation, the solubility, water-holding capacity, and viscosity significantly increased and the particle size decreased. Moreover, the glucose adsorption capacity (2.1 mmol g-1), glucose dialysis retardation index (75.3%), and α-glucosidase inhibitory (71.4%, mixed reversible inhibition) activity of the fermented MBE (FMBE) were greater than those of the unfermented MBE (0.99 mmol g-1, 32.1%, and 35.1%, respectively). The FMBE presented better cholesterol and sodium cholate (SC) adsorption properties and the adsorption was considered inhomogeneous surface adsorption. Fermentation increased the bioactive component content and improved the physicochemical properties of MBE, thereby improving its hypoglycemic and hypolipidemic properties. This study not only resolves the problem of millet bran waste but also encourages the development of higher value-added application methods for millet bran. © 2024 Society of Chemical Industry.

The effects of different fiber fractions from sour cherry (Prunus cerasus L.) pomace and fiber modification methods on cake quality.

Sour cherry pomace is the largest byproduct of sour cherry processing with more than 0.4 million tonnes per year. In this study, sour cherry pomace powder (SCPP) has been treated individually or by a combination of microwave (MW), enzymatic hydrolysis, and high pressure to increase soluble dietary fiber (SDF) content. Then, the untreated or treated forms of SCPP, their SDF, and insoluble dietary fiber (IDF) isolates were added (5%) to the reduced-fat cake. Rheological, physical, and textural properties of the full-fat (50%) and the reduced-fat (25% fat) cakes enriched with dietary fiber (DF) were compared. SDF enrichment minimized the negative effect of fat reduction in the cake. Water absorption, mixing tolerance, hardness, and springiness values of the SDF-enriched samples were found as the lowest. Extensibility, energy, weight loss, and cohesiveness values were found to be the highest values with the addition of SDF. All treatments helped to decrease mixing tolerance, dough development, and stability time. MW was the critical treatment for DF modification. Individual MW-treated DF samples increased resistance to extension of the dough samples as compared to the untreated SDF, IDF, and SCPP. Nevertheless, SDF showed better performance in acting as a fat replacer than IDF and SCPP. PRACTICAL APPLICATION: The soluble dietary fiber (SDF) isolate minimized the negative effect of fat reduction in cakes. Water absorption and mixing tolerance of the dough were measured as the lowest. The hardness and springiness of soluble dietary fiber-enriched cakes were found to be the lowest. Extensibility and weight loss reached the highest value when SDF was used. Treatments helped decrease mixing tolerance, dough development, and stability time.

Physicochemical and emulsification properties of okara-derived soluble dietary fiber modified by steam explosion

The effective utilization of by-products still poses a challenge in the food industry. In this work, soluble dietary fiber (SDF) extracted from okara was modified by steam explosion (SE) via adjusting steam pressure (1.0, 1.5, and 2.0 MPa) and SE duration (60 and 120 s). The structural and emulsification properties of modified SDF were studied. The untreated SDF exhibited a low yield (5.17%) and poor emulsification properties due to its large molecular weight (162.67 kDa), compact structure, and high interfacial tension (14.27 mN/m). SE increased SDF content by a maximum of 30.31%, 4.86 times higher than that of untreated SDF. Under mild SE conditions (1.0 MPa for 60 s), SDF displayed a loose structure with abundant side chains and a higher glyoxylate content (26.77%). Its near-neutral contact angle (82.0°) and lower interfacial tension (12.69 mN/m) endowed it with higher emulsification capacity, smaller emulsion droplet size, and enhanced emulsifying stability. The molecular weight of SDF decreased and the specific surface area enlarged with increasing SE intensity. Notably, SDF exhibited the best interfacial adsorption characteristics under SE of 2.0 MPa for 120 s, attributed to its low molecular weight (46.99 kDa) and higher protein content (7.58%). Overall, the improved emulsification properties of SDF were attributed to the synergistic effects of amphiphilic equilibrium, electrostatic repulsion, spatial resistance, and enhanced droplet-to-droplet interactions.

Effects of dietary fibre source and content and extrusion conditions on the physicochemical composition and physical quality of fibre‐enriched lentil snacks

SummaryThe growing recognition of the health benefits associated with dietary fibre and the deficit in its daily intake are propelling the food industry to develop a variety of fibre‐enriched products including puffed snacks. Incorporating rich sources of fibre into pulse‐based foods can supplement the insufficient daily dietary fibre intake. To produce fibre‐enriched puffed pulse snacks and ready‐to‐eat breakfast cereals, three different fibre sources, namely carrot powder (CP), wheat bran (WB) and red lentil hulls (LH), were added to red lentil (RL) flour at 0%, 10% and 20% levels (w/w) and extruded at three extrusion moisture contents (MC), i.e., 18%, 20% and 22% (db). Incorporation of all three fibres into RL flour significantly (P ≤ 0.05) increased the total and insoluble dietary fibre contents and hardness and decreased the expansion index, brightness and crispiness of extrudates. Scanning electron microscopy images revealed that the fibre‐enriched extrudates had thicker cell walls with smaller cells when qualitatively compared to RL extrudates with no fibre addition. CP containing extrudates had significantly (P ≤ 0.05) higher soluble dietary fibre (SDF) content compared to extrudates containing WB and LH. WB containing extrudates were significantly (P ≤ 0.05) harder and less expanded than CP and LH containing extrudates at the same MC. The increase in fibre incorporation level increased the hardness of CP and WB containing extrudates but did not affect LH containing extrudates. Fibre incorporation level also increased the colour differences between RL extrudates with and without fibre enrichment. Increasing MC significantly (P ≤ 0.05) increased the SDF and hardness and decreased the expansion index of extrudates. These results can potentially pave the way for the production of fibre‐enriched pulse‐based puffed products, namely, snacks and ready‐to‐eat breakfast cereals, that are texturally and structurally appealing to consumers.

Xylanases and high-degree wet milling improve soluble dietary fibre content in liquid oat base

The growth of plant-based food and drink substitutes has led to increased interest in oat-based milk substitute as a dairy milk alternative. Conventional liquid oat base (LOB) production results in a fibre-rich insoluble by-product and loss of valuable macronutrients. This study investigates the use of xylanase enzymes to release insoluble arabinoxylan (AX) fibre and employs different degrees of milling in the LOB manufacturing process, with the aim to reduce insoluble waste and simultaneously increase soluble dietary fibre in oat-based milk substitutes. The combination of decreased mill gap space from 1 to 0.05 mm and addition of GH10 xylanase, resulted in a homogenous LOB product and solubilization of all available AX. Potential prebiotic arabinoxylooligosaccharides of DP3-7 from GH10 hydrolysis were identified using HPAEC-PAD and MS analysis. These findings demonstrate the value of utilizing xylanases and fine-milling in LOB manufacturing, offering a sustainable approach to maximize health benefits of oat-based beverages.

Solid-state fermentation by S. cerevisiae with high resistance to ferulic acid improves the physicochemical properties of wheat bran and quality of bran-rich Chinese steamed bread.

Wheat bran has numerous health benefits, but its poor processing and sensory properties limit its application in the staple food industry. Fermentation by S. cerevisiae changes the performance of wheat bran. However, high levels of ferulic acid (FA) inhibit S. cerevisiae. The effects of solid-state fermentation of S. cerevisiae with high resistance to FA on the physicochemical properties of wheat bran and the quality of bran-rich Chinese steamed bread (CSB) were investigated. The results showed that the growth of S. cerevisiae was inhibited by FA in a dose-dependent manner. Short-term adaptation strategies efficiently improved the tolerance of S. cerevisiae to FA stress. Compared with the parental strain (PS), fermentation of the short-term adapted strains (adapted strains) significantly increased the FA, total phenol, and soluble dietary fiber content in wheat bran. Wheat bran fermented by the adapted strains had a higher antioxidant capacity than wheat bran fermented by PS. In addition, compared with the PS, the wheat bran fermented by the adapted strains can decrease the hardness, improve the specific volume, and the quality of CSB. Thus, solid-state fermentation of the adapted strain is a potentially effective method to improve the nutritional and physicochemical properties of wheat bran as a cereal food ingredient.

Composition, structural, physicochemical and functional properties of dietary fiber from different milling fractions of black rice bran

Black rice bran is a superior dietary fiber (DF) resource. However, the lack of specific distribution and functionality of DF in black rice bran has constrained its refined processing. This study divided black rice bran into five equal bran fractions (BF) by stepwise milling to obtain BF1(outermost layer) to BF5 (the innermost layer). The contents, structure, physicochemical and functional properties of DF in each bran fractions were investigated. The results revealed that the insoluble, soluble and total dietary fiber (IDF, SDF and TDF) contents were 17.52 ± 0.48 to 31.14 ± 0.96, 2.03 ± 0.20 to 3.86 ± 0.01 and 19.57 ± 0.28 to 34.61 ± 1.10 g/100 g dry basis, respectively. Compared to BF1, the TDF content of BF2–BF5 was reduced by 3.90, 3.20, 21.74 and 43.46%, respectively. The main monosaccharides in both IDF and SDF were xylose, glucose, arabinose and galactose. The molecular weight of SDF samples ranged from 17.19 ± 1.95 to 36.32 ± 0.80 kDa. The outer bran fractions (BF1–BF3) IDF exhibited higher water swelling, water retention, oil adsorption capacity, together with cholesterol and sodium nitrite adsorption capacity than those of inner bran fractions (BF4–BF5), owing to their lower crystallinity and well-developed porous structure. These results provide essential data for the development of black rice DF-based food processing with enhanced functional benefits.

Effect of cellulase on antioxidant activity and flavor of Rosa roxburghii Tratt

Cellulase can increase the soluble dietary fiber (SDF) content in Rosa roxburghii Tratt (RRT), but the effects on polyphenol content, bioactivity, and flavor are unknown. This study analyzed the changes in SDF content, total phenolic content, antioxidant activity and flavor before and after cellulase treatment. Cellulase treatment increased the SDF and total phenolic content of RRT by 13 % (P < 0.05) and 25.68 % (P < 0.05), respectively, and increased the antioxidant activity. HS-GC-IMS identified a total of 42 volatile compounds present, and ROAV analysis revealed that the characteristic aroma compounds of RRT were mainly aldehydes, alcohols, and ethers. The electronic nose and tongue results were consistent with the HS-GC-IMS analysis, indicating the positive effect of cellulase on the quality of RRT. Cellulase treatment significantly improved the oxidative activity and flavor performance of RRT. These results of RRT, providing practical guidance for improving the flavor and product quality.

Effect of steam explosion treatment on structural and physicochemical properties, and potential application of soluble dietary fiber from grain and oil processing by‐products: A review

AbstractBackground and ObjectivesGrain and oil processing by‐products contain dietary fiber with high quality, but most of them have not been utilized due to their high content of insoluble dietary fiber and coarse texture, which are detrimental to the quality improvement of cereal food.FindingsSteam explosion treatment can transfer dietary fiber from insoluble to water‐soluble resulting in a high content of water‐soluble dietary fiber. The content of soluble dietary fiber in cereal processing by‐products with steam explosion treatment is increased from 27.48% to 171% via optimal conditions of steam explosion treatment. The structure of dietary fiber from cereal processing by‐products is disrupted to a honeycomb porous shape, therefore, the physicochemical properties of dietary fiber are improved, such as hydration capacity, oil, cholesterol, and bile salts binding capacity, hypoglycemic capacity, and antioxidant activity.ConclusionsSteam explosion treatment is a rapidly developing and extremely promising pretreatment technology for physicochemical properties enhancement of dietary fiber from grain and oil processing by‐products.Significance and NoveltyThis review can provide some useful references for the properties improvement of soluble dietary fiber in grain and oil processing by‐products by steam explosion pretreatment. It may facilitate the application of soluble dietary fiber in the food industry.

Structural, physicochemical and functional properties of dietary fibers from tea residue modified by steam explosion

Effects of steam explosion (SE) treatment (0.3–1.0 MPa, 30–90s) on the physicochemical and functional properties of dietary fiber (DF) extracted from tea residue were investigated. Results showed that SE led to the formation of porous and less compact microstructures of tea residues. Compared with the control sample (12.41 g/100 g), the content of soluble dietary fiber (SDF) was markedly increased by SE, reaching the maximum of 23.03 g/100 g when steam explored at 0.5 MPa for 90 s, due to the degradation of insoluble dietary fiber (IDF). The physicochemical and functional properties were significantly influenced by SE treatments. IDF exhibited decreased water holding capacity (WHC), swelling capacity (SC), oil holding capacity (OHC) after SE, whereas the physicochemical properties of SDF from SE-treated tea residues (0.3 MPa, 90s) were greatly improved. The glucose absorption capacity (GAC), cholesterol adsorption capacity (CAC), and nitrite ion adsorption capacity (NIAC) of both IDF and SDF showed trends of first increasing and then decreasing, indicating that excessive SE treatment resulted in poor properties of DF. These findings are of great value for the high-value utilization of agricultural by-product and development of functional foods.

Quality of High-Fibre Pasta Supplemented with Watermelon Rind Powder with Different Particle Sizes.

Watermelon rind, a by-product of watermelon juice processing, contains large amounts of dietary fibre and phenols with antioxidant capacity. The use of agro-industrial by-products would both improve economic benefits and reduce environmental emissions. The aim of this research is to examine the effect of the particle size of watermelon rind powder on the quality of high-fibre pasta. The nutritional, physical and physicochemical quality of three samples of watermelon rind powder, sieved through three sieves with aperture size of 400, 210 and 149 μm, were analysed. Durum wheat semolina with watermelon rind powder mass fraction of 10 % were mixed and used to make pasta. Nutritional, textural and cooking quality, sensory acceptability, in vitro glycaemic index and antioxidant bioaccessibility of high-fibre pasta with added watermelon rind powder of different particle sizes were evaluated and compared. When the sieve aperture size was reduced from 400 to 149 µm, the soluble dietary fibre and total phenolic contents of watermelon rind powder were increased by 35 and 15 %, respectively, while its insoluble dietary fibre content was decreased by 21 %. Decrease in sieve aperture size from 410 to 149 µm reduced phenolic bioaccessibility of the fortified pasta from 63 to 57 %, but enhanced its predicted glycaemic index from 50 to 69. It also decreased the pasta hardness by 13 %, but improved its elongation rate and tensile strength by 13 and 40 %, respectively. The finer the particles of the watermelon rind powder, the longer the optimal cooking time, the higher the water absorption index, and the lower the cooking loss of the supplemented pasta. Consumers did not notice any significant differences in the overall acceptability among all pasta samples. The particle size of the watermelon rind powder had a major effect on nutritional value, texture and cooking quality of the fortified pasta. In particular, the predicted glycaemic index and antioxidant bioaccessibility of high-fibre pasta were significantly affected by the particle size of the dietary fibre material used in the recipe.

Effects of high-pressure processing on the physicochemical and adsorption properties, structural characteristics, and dietary fiber content of kelp (Laminaria japonica)

To investigate the effects of high-pressure processing (HPP) on the physicochemical and adsorption properties and structural characteristics of kelp, kelp slice (KS) and kelp powder (KP) were treated under different pressures (300, 450, and 600 MPa) for 5 and 10 min. Compared to untreated KP, HPP-treated KP yielded a 1.31-fold increase in water holding capacity (600 MPa/5 min), a 0.12-fold increase in swelling capacity (450 MPa/10 min), a 1.33-fold increase in oil holding capacity (600 MPa/10 min), a 10-fold increase in glucose adsorption capacity (450 MPa/10 min), and a 0.22-fold increase in cholesterol adsorption capacity (163.1 mg/g DW at 450 MPa/10 min), and exhibited good Cd (Ⅱ) adsorption capacity when its concentration was 10 mmol/L in the small intestine. The physicochemical properties of HPP-treated KS were not improved due to its low specific surface area. In addition, HPP treatment efficiently reduced the particle size of KP and increased its total and soluble dietary fiber content by 17% and 63% at 600 MPa/10 min, respectively. Scanning electron microscope micrographs demonstrated that the surface of HPP-treated KP was rough and porous, and the specific surface area increased with increasing pressure and processing time. To conclude, the results obtained in the present study suggest that HPP is a promising processing method for improving the functionality and structural characteristics of KP and provide a theoretical basis for the utilization of HPP-treated KP as a fiber-rich ingredient in the functional food industry.

Enzymatic treatment of pineapple pomace and its application into fiber-rich biscuit making

Pineapple pomace is a by-product of the pineapple juice industry. With high dietary fiber content, it has become a potential source added to fiber-rich foods in recent years. However, the ratio of soluble dietary fiber (SDF) to total dietary fiber (TDF) in pineapple pomace is very low while both SDF and insoluble dietary fiber (IDF) have positive effects on human health. In this study, the enzymatic treatment conditions of fresh pineapple pomace with commercial cellulase on its dietary fiber profile were investigated. The addition of non-enzyme-treated pineapple pomace (NTPP) and enzyme-treated pineapple pomace (ETPP) into biscuit formulation was then examined. The appropriate cellulolytic treatment conditions were the water content of 86 %, the cellulase concentration of 7.5 U/g dry matter, and the treatment time of 3 h, under which the SDF content was enhanced from 1.26 to 4.43 % while the SDF/TDF ratio was improved from 2.2 to 9.5 % as compared to those of NTPP. The use of NTPP or ETPP in biscuit formula increased TDF content and antioxidative capacities as well as hardness of the product. At the ratio of 30 %, the biscuits made with ETPP were lower in hardness, greater in SDF content, SDF/TDF ratio, antioxidative capacities, and overall organoleptic acceptance compared to the biscuits made with NTPP.

Debranning of wheat: Quality of flour and thermomechanical, microstructural, and extensional properties of dough

This study investigated the impact of debranning degrees (0, 3, 6, 9 and 12% by weight) on the qualities of wheat flour and dough. The physicochemical and pasting properties of wheat flour and thermomechanical, microstructural, extensional and rheological properties of wheat dough with different debranning degrees were assessed. The insoluble dietary fiber, soluble dietary fiber, protein, and ash contents for debranned wheat flour were significantly higher than that of refined flour. The content of protein was the highest when the debranning degree of wheat was 6%. Debranning degree of 6% significantly increased the gluten index for wheat flour and showed better pasting and mixing properties than untreated samples. Debranning treatment increased the L* value and decreased the a* and b* values of the wheat flour. Furthermore, when the debranning degree increased, the protein matrixes were more continuous and compact, and the starch granules were better entrapped in the gluten network. Debranning treatment caused significant increases in the dough's resistance to extension, extensibility, extensibility area, and extensibility rate, and a decrease in the dough's viscoelasticity. The debranning degree of 6% could effectively improve the parameters such as mixing properties, microstructure, and extensional properties of wheat dough.