| In this experiment,coconut flour which is the by-product of coconut after squeezing coconut milk was taken as raw material. Firstly,the basic composition and the physico-chemical properties of coconut flour was analysed and the extraction process of dietary fiber from coconut flour by chemical and enzymatic method was investigated.Secondly,the physico-chemical and functional properties of the dietary fibre was also studied.Finally,We also studied the application effect in bread which was added by different levels of coconut flour dietary fiber.The main conclusion is as follows:Major constituents of coconut flour are crude fiber(25±1.33%),protein(6.58±0.15%),soluble total sugar ( 2.18±0.17% ),fat ( 55.12±1.52% ) .However,coconut flour after skimming fat contains 56.35±2.42% of crude fiber,17.47±1.49% of protein,10.97±1.21%of soluble total sugar and 1.98±0.11% of fat.The WHC,OHC,SC of coconut flour is 6.15±0.34g/g, 3.62±0.53g/g,10.36±1.36 mL/g .Coconut flour after degreasing improved the physico-chemical properties.WHC increased 0.99 g/g,OHC increased 0.66 g/g,SC increased 4.06 mL/g.This study determined the optimum extraction technology of chemical method and enzymatic by single factor and orthogonal test . The highest rate of dietary fiber by chemical extraction method was 77.01% when the pH was 10,solid to liquid was 1:25,temperature was 50?, time was 120 minutes of alkali and the pH was 4 ,solid to liquid was 1:15, temperature was 40?, time was 100 minutes of acid. The optimal condition of extracting dietary fiber with enzymes was as follow:for amylase, 45minutes, 0.3% amount of enzyme;for protease ,45minutes,0.2% amount of enzyme; for glucoamylase, 30minutes,20uL amount of enzyme.The highest rate was 89.68%.The WHC?OHC?SC?CEC of SDF and IDF obtained by chemical and enzymatic was studied.The physico-chemical characteristics of C-IDF were as follows.the SC was 16.48±0.32mL/g,the WHC was 11.92±0.96 g/g,the OHC was 5.21±0.23g/g,the CEC was 0.40±0.02mmol/L.The physico-chemical characteristics of C-SDF were as follows: the WHC was 8.37±0.64g/g,the OHC was 3.14±0.19g/g,the CEC was 0.55±0.03mmol/L.The physico-chemical characteristics of E-IDF were as follows: the SC was 15.33±0.51mL/g,the WHC was 12.71±0.84g/g,the OHC was 6.51±0.35g/g,the CEC was 0.55±0.02mmol/L.The physicochemical characteristics of E-SDF were as follows: the WHC was 0.71±0.02g/g,the OHC was 3.28±0.21g/g,the CEC was 5.30±0.34mmol/L.Adsorption of C-SDF and E-SDF for cholesterol at pH 7 were 13.85±0.30mg/g and 5.19±0.24mg/g. Adsorption of C-IDF and E-IDF for cholesterol significantly decreased,at pH 7 were 4.37±0.16mg/g and 3.21±0.13 mg/g.NO2- scavenging capacity of C-SDF and E-SDF at pH 2 were 539.04±5.52 ug/g and 631.51±5.34ug/g; however,NO2- scavenging capacity of C-IDF and E-IDF significantly decreased,at pH 7 were 177.05±5.43ug/g and 156.51±4.52 ug/g.The in vitro antioxidant capacity study found that E-SDF has the strongest antioxidant capacity.Scavenging capacity for HO· and Iron(?) chelating activity of E-SDF at lmg/mL was 93.26% and 93.42%.Reducing power,scavenging capacity for DPPH· and total antioxidant capacity of E-SDF at 40mg/mL was 31.40%,88.40% and 80.76%.Scavenging capacity for O2- at 30mg/mL was 78.25%.Additing coconut flour dietary fiber in the bread would reduce specific volume and increase hardness of bread. However,appropriate addition of coconut flour dietary fiber reasonably in bread can improve the appearance,color,taste, elasticity,flavor, internal structure. Coconut fiber bread can reduce moisture migration rate . The water loss rate of contrast bread was 15.5% within seven days, the change of the C-IDF is 12.1%?10%, the change of the E-IDF is 12.5%?10.2%,the change of C-SDF is 12.75%?10.5%,the change of E-SDF is 14.55%?13.05%. Coconut fiber bread can reduce hardness increase rate. The hardness increasing rate of contrast bread was 226.34% within seven days, the change of the C-IDF is 12.1%?10%,the change of the E-IDF is 12.5%?10.2%,the change of coconut flour is 134.84%, the change of C-IDF is 182.30%?127.67%.the change of E-IDF is166.67%?125 72%, the change of C -SDF is 212.33%?165.77%,the change of E-SDF is 220.39%?129.72%?C-IDF and E-IDF has consistent effect on bread.The different proportion of C-SDF have less effect on the bread, and is conducive to the bread.However, the different proportion E-SDF greatly influenced on bread,the impact of a larger proportion E-SDF is bad in bread. |
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