| In this study,different varieties of fresh apricots in Xinjiang were used as experimental materials.The fresh apricots were de-mucked,de-nucleated and dehulled to obtain almonds,which were then naturally dried.The almonds were defatted by the Soxhlet extraction method to obtain almond defatted powder.The almond protein isolate and almond albumin were extracted by the method,and the almond protein isolate was used as the research object to analyze its composition,functional properties and structural properties;the almond albumin was used as the research object to analyze its structural properties;and the almond protein was used to develop instant almond tofu.It provides important reference value and new ideas for the research and development of almond functional foods.The main research conclusions are as follows:(1)The composition of 10 varieties of almond defatted powder and protein isolates were analyzed,and the functional properties of 10 varieties of almond protein isolates were studied under different p H values(6,8,10,12).The results of composition research showed that: in the composition of almond defatted powder,Hanging dried apricots have the highest moisture content,light apricots have the highest ash content,and the protein content ranges from 37.57% to 52.70%,among which small white apricots have the highest;In the composition of almond protein isolate,sugar apricot has the highest moisture content,and Tuokexun apricot has the highest ash content,and the protein content ranges from 77.75% to 91.30%,Among them,hanging dried apricots,big white apricot and hairy apricots all reached more than 90%.The research results of functional characteristics are as follows:with the increase of p H value,the solubility of 10 varieties of almond protein isolate will be improved to different degrees,and the solubility of small white apricot is the highest near neutral;while the water holding capacity increases with the increase of p H value There is a downward trend,but the water holding capacity of small white apricot is the most stable near neutral;the oil holding capacity of small white apricot and light apricot is higher than that of other varieties;the emulsification of almond protein isolate of 10 varieties is better when the p H value is 8,the emulsifying properties and stability of Tuokexun apricots and small white apricots are the best near neutral;The foaming stability of hanging dried apricots,big white apricots,hairy apricots and red apricots is relatively good.(2)The structural properties of 10 varieties of almond protein isolates were studied.The research results showed that the total amino acid content of 10 varieties of almond protein isolate was between88.73% and 98.51%,the essential amino acid content was between 23.76% and 26.06%,and the medicinal amino acid content was between 63.7% and 71.37%,Among them,hairy apricots is the highest.Among the secondary conformations of the 10 varieties of almond protein isolates,?-sheet and ?-turn are dominant,while the content of random coil and ?-helix structure is relatively small.The surface hydrophobicity of big white apricot almond protein isolate is the highest;through the UV second derivative spectrum and fluorescence spectrum analysis,it can be seen that the surface of the small white apricot almond protein isolate has the highest tyrosine content,The content of tryptophan on the surface of almond protein isolate of Tuokexun apricot,millet apricot and hanging dried apricot was significantly higher than that of other varieties;The content of total sulfhydryl group,free sulfhydryl group,disulfide bond and carbonyl group of sugar apricot almond protein isolate was the highest;The subunits of the 10 varieties of almond protein isolates were widely distributed,mainly distributed around the molecular weights of 20 KDa and 23 KDa and around 27,35,39,54,and 63KDa;The electrostatic repulsion between the molecules of the hairy apricot almond protein isolate was the strongest;the stability of the solution system with the smallest average particle size of the hanging dry apricot almond protein isolate was the best.(3)The structural properties of almond albumin in 10 varieties were studied.The research results showed that the protein content of almond albumin in 10 varieties ranged from 65.21% to 81.47%,and the protein content of small white apricot was the highest;the total amino acid content of almond albumin was between 69.05% and 94.11%,Small white apricots and olive apricots are the highest;essential amino acids are between 18% and 26.13%,and red apricot is the highest;in the secondary structure of almond albumin of 10 varieties,?-turn and random coil are the main ones,and the content of ?-sheet and ?-helix structure Relatively few;the surface hydrophobicity of light apricot and sugar apricot is the highest;through the analysis of ultraviolet second derivative and fluorescence spectrum,it can be seen that the content of tyrosine on the surface of almond albumin of big white apricot is the highest,and the content of tryptophan on the surface of almond albumin of hanging dried apricot is the highest.The content of acid is the highest;the content of total sulfhydryl and disulfide bonds in small white apricot is the highest;the content of free sulfhydryl in Tuokexun apricot is the highest;hairy apricots has the highest carbonyl content;Among them,the subunit distribution of olive apricot reaches 19 subunit species,and the subunits of 10 varieties of almond albumin are mainly distributed on small molecular peptide chains below 17 KDa,and the subunit content is the most distributed in the 8 KDa band;The electrostatic repulsion between sugar apricot almond albumin molecules is the strongest;the stability of the solution system with the smallest average particle size of millet apricot almond albumin is the best.(4)Combined with the functional characteristics of various varieties of almond protein,the product "almond protein tofu",a casual dessert of small white apricot protein,was developed.Using the single-factor orthogonal experimental analysis method,the sensory score of instant almond tofu was studied by taking the mass ratio of almond protein to soybean,the ratio of almond and soybean total material to water,the amount of sugar,and the amount of glucono-?-lactone as factors.Impact.It is clear that the optimal processing technology of instant almond tofu requires that the mass ratio of almonds and soybeans is 1:6(g/g),the ratio of almond protein powder and soybean total material to water is 1:9(g/ml),and sugar is added.The amount of glucono-?-lactone was 7%,and the addition amount of glucono-?-lactone was 0.3%.And developed a homemade tofu instant package that is easy to store and transport,including 7g of almond protein soy milk powder,0.6g of glucono-delta-lactone coagulant,and 12 g of sugar.Add water to 100 ml,and heat it at 85 °C for 20 minutes Ready-to-eat marzipan tofu can be formed.And it was found that adding small white apricot almond protein powder to soybean tofu can reduce the hardness and stickiness of tofu and help to improve the elasticity,chewiness and water holding capacity of tofu. |
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