Modifi cation of wheat bran insoluble and soluble dietary fibers with snail enzyme

Insoluble dietary fiber(IDF)and soluble dietary fiber(SDF)extracted from wheat bran were modifi ed by snail enzyme and their physicochemical properties(water retention capacity and oil retention capacity),functional properties(cholesterol adsorption capacity,glucose adsorption capacity and antioxidant activity)and structural characterizations were evaluated.The results showed that snail enzyme modification led to the significant increase in oil retention capacity of IDF,glucose adsorption capacity and cholesterol adsorption capacity of IDF and SDF.Enzymatic modification also markedly improved the DPPH radical scavenging capacity and reducing power of IDF and SDF.Meanwhile,scanning electron microscopy(SEM)analysis indicated the microstructures of IDF and SDF powders were signifi cantly changed.Fourier transfer-infrared spectrometry(FT-IR)showed that snail enzyme modifi cation could degrade the part of cellulose and hemicellulose of IDF and SDF.All these improved physicochemical and functional properties of IDF and SDF might depend on their structural changes.It suggested that snail enzyme modifi cation could effectively improve physicochemical and functional properties of IDF and SDF from wheat bran.

Study on Functional and Structure Properties of Soluble Dietary Fiber Modified by Extrusion-expansion Technology from Peanut Shells

[Objectives] This study was conducted to investigate the feasibility of using modified peanut dietary fiber as a functional food ingredient. [Methods]Using peanut shells as a test material,the process parameters of soluble dietary fiber( SDF) modified by extrusion and expansion were studied,and the functional and structural characteristics of SDF before and after modification were discussed. [Results] The optimum conditions were as follows: screw speed 200 rpm,temperature 130 ℃ and moisture content 20 %,and the SDF extraction yield was 22. 3%. The modified SDF showed BCmax values of( 378. 5 ± 5. 3),( 278. 3 ± 3. 2)and( 167. 2 ± 2. 5) μmol/g and BCmin of( 30. 4 ± 1. 3),( 63. 4 ± 3. 7) and( 71. 3 ± 4. 2) μmol/L,for Pb,As and Cu,respectively,indicating that the adsorption to the three heavy metals was enhanced. The modified SDF had a porous network like honeycomb and swelled structure. [Conclusions]Therefore,it is feasible to modify SDF by extrusion and expansion.

The effects of dietary fiber level on nutrient digestibility in growing pigs

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 x 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease （P =0.] O） as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased （P 〈0.0]） when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased （P 〈0.01）. The digestible energy and metabolizable energy content of diets decreased （P 〈0.01） as the total dietary fiber increased.

A Review of the Associations between Dietary Fiber Intake and Cancer Prevention or Prognosis

The increase in tumor incidence is closely related to dietary factors.In recent years,many researchers have carried out in-depth research to investigate whether increasing the intake of dietary fiber can prevent tumors and improve the prognosis,but the results have been unclear.We herein searched the literature in common academic databases and incorporated and summarized the relevant articles.The literature clearly indicates that dietary fiber can protect against the following cancers:colorectal cancer,breast cancer,pancreatic cancer,ovarian cancer,and head and neck cancer.There is also evidence that dietary fiber intake can exert protective effects against cancers of the liver,lung,stomach,small bowel,kidney,and esophagus,as well as lymphoma,but the data have so far been relatively limited.The effects on endometrial cancer and prostate cancer still remain uncertain.In terms of the effects on the cancer prognosis,dietary fiber does not appear to have an impact on colorectal cancer or breast cancer.Although more research is needed for some kinds of cancer,it is clear that increasing the intake of dietary fiber is beneficial for preventing the occurrence and development of several major types of cancer,with no major adverse effects.We therefore recommend that most of individuals increase their intake of dietary fiber.

Characterization of a new 4,6-α-glucanotransferase from Limosilactobacillus fermentum NCC 3057 with ability of synthesizing low molecular mass isomalto-/maltopolysaccharide

4,6-α-Glucanotransferase(4,6-α-GT)converts starch into product with increasedα(1-6)glycosidic bonds ratio,and this product is a new type of soluble dietary fiber with property of escaping small intestine digestion.4,6-α-GT gained interest recently because of their potential use in enzymatic synthesis of soluble dietary fiber.In this study,a putative GtfB sequence from Limosilactobacillus fermentum NCC 3057 was identified.This sequence was truncated and expressed in Escherichia coli to obtain the protein L.fermentum NCC 3057 GtfBΔN.GtfBΔN showed optimal activity at 35℃and pH 6.0,and it converted amylose V to isomalto-/maltopolysaccharide(IMMP)with low molecular mass(3.1 kDa).This IMMP product contains 72%α(1-6)glycosidic bonds,and it showed 64%indigestible content in vitro digestion experiment.These results indicate that the product of L.fermentum NCC 3057 GtfBΔN is a soluble dietary fiber.Finally the X-ray crystal structure of GtfBΔN(2.4Å)was resolved.Based on the GtfBΔN structure,we offer an insight about that three loops of domain C may be related to the molecular mass of IMMP product.