| Setaria italica(L.)Beauv is a specie of Setaria of Gramineae,which is planted in arid and semi-arid areas of China as one of the important food crops.Foxtail millet as people commonly known is peeled Setaria italica.Foxtail millet is becoming a health food in our daily life because of its abundant dietary fiber,phenolic compounds and essential trace elements in human body.Setaria italica is the research object in this paper,this paper established millet water absorption kinetics model;confirmed the process of instant millet porridge,elected the best processing technology according to the quality of the instant millet porridge,and studied the effects of the processing procedure of millet porridge on some parts of nutrients and antioxidant capacity;determined part of nutrients and antioxidant capacity of black millet;studied the germination millet amino acids in the process of change by high performance liquid chromatography(HPLC)method.Through the all experiments,obtained the following results:1.Peleg model was used in studying the properties of millet soaking conditions at different temperatures and times,established millet absorbing kinetic equation at 25?60?:Mt=11.0826+t/[0.0037-3×10-5T +(0.055-0.0002T)t],determined that the rate constant and volume constant were decreased with temperature rising.Obtained activation energy of millet soaked in water by Arrhenius equation which is 11.003 kJ/mol.2.The processing basic method of instant millet porridge is Determined,which included soaking,high-pressure cooking,pre-cooling,freeze-drying and sealed packaging.We obtained porous spatial network structure of instant foxtail millet by scanning electron microscopy,analyzed that processing time was only having influence on the texture properties of rehydration millet porridge,and drying temperature had significant effect on WSI and gumminess.In addition,rehydration time and foxtail millet porridge moisture content existed a negative correlation relationship.We got a best processing technology of instant foxtail millet porridge by comprehensive evaluation of rehydration qualities,texture properties and sensory evaluation:millet and water quality ratio of 1:7.8,soaking 60 min at room temperature,121?high-pressure cooking 7 min,pre-freezing 6 h in-35?,-22?freeze drying 16 h,sealed packaging.3.The contents of amino acids,phenolic acids,flavonoids and antioxidant ability of instant foxtail millet porridge four-stage process were measured,which were pre-machining,after the high pressure cooking,after freeze drying and after rehydrating,the results were as follows:total amino acids and essential amino acids substantially unchanged before and after processing.Bound phenolic acids content decreased 27.87%after high-pressure cooking,freeze-drying and rehydration had little effect on the phenolic acids content,the proportion of phenolic acids increased about 9.12 percents at the end of machining.Free flavonoids significantly reduced after high-pressure cooking,when compared with unprocessed it was reduced 29.57%,while the change of bound flavonoids was not significant after cooking.Different kinds of phenolic acids and flavonoids changed varied.All processing had influence on millet phenol extraction DPPH scavenging ability,after rehydration which were reduced 55.83%and 88.39%respectively of free phenolic acids and bound phenol extraction.Foxtail millet phenol extraction ferric iron reduction ability declined significantly after high pressure cooking,free and bound phenol extraction of it were reduced by 30.08%and 39.74%respectively,freeze drying and rehydration to extraction ferric iron reduction ability effect were not significant.4.Part of black foxtail millet nutrition composition and antioxidant capacity were determined,black foxtail millet total amino acid content was(10.23±1.09)g/100 g,essential amino acid content was(3.44±1.34)g/100 g,proportion of amino acid was 33.65%.Black foxtail millet total phenol content was(112.85±7.26)mg gallic acid/100 g,free state of phenolic acids accounted for 39.65%.Flavonoids content was(2928.1±354.6)mg rutin/100 g,including free state proportion of flavonoids was 70.65%.Black millet free phenol extraction ability of DPPH free radicals was 16.21 mg Vc/100 g,ferric iron reduction ability was(57.53±4.17 mm)mg FeSO4/100 g,while bond phenol extraction ability of DPPH free radicals was 44.83 mg Vc/100 g,ferric iron reduction capacity was(32.62±0.65)mg FeSO4/100 g.5.Amino acid contents of black foxtail millet germination at different time points were measured within 96 h,total amino acid content of germination millet varied significantly,it reached the highest(195.36±16.95)mg/g at germinating 6 h,rosed 29.03%compared with 0 h;essential amino acid at the 12 h reached the peak(73.807±8.85)mg/g,contents of different kinds of amino acids reached maximum at different times,enrichment effects of Arginine,Threonine,Glutamic acid,Lysine and Aspartic acid were obvious,increased respectively 55.91%,51.41%,73.31%,107.81%and 128.86%compared with 0 h. |
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