| Dendrobium officinale is a kind of orchid plant that can be used by the whole plant.Its stem,flower and leaves are rich in nutrients and functional components.It has many functions such as anti-oxidation,hypoglycemia and hypolipidemia,and has outstanding health value and broad development prospect.At present,the research on Dendrobium officinale is mainly focused on the stem,and the development of Dendrobium officinale flowers and leaves is less,which is easy to cause the waste of Dendrobium officinale resources.In this paper,the flowers and leaves of Dendrobium officinale were used as the main raw materials,which were mixed with chrysanthemum and jasmine,mulberry leaves and lotus leaves respectively in proportion.The preparation technology,antioxidant function,hypoglycemic function,product quality and volatile components of the two kinds of Dendrobium officinale herbal tea were studied.Two novel Dendrobium officinale herbal tea products with good antioxidant and hypoglycemic functions and unique flavor were prepared in order to provide an effective way for making full use of Dendrobium officinale resources and diversified development of Dendrobium officinale products.The main research contents and results are as follows:1.Analysis of the nutritional components and functional components of Dendrobium officinale herbal tea.The flowers of Dendrobium officinale,leaves of Dendrobium officinale and chrysanthemum contain higher crude fat,the leaves of Dendrobium officinale,chrysanthemum and lotus leaf contained higher crude fiber,crude protein content is higher in lotus leaves and chrysanthemum,six kinds of amino acid and trace element content rich raw materials,and of jasmine and lotus plants E/T value and E/N value achieve ideal protein standard,the other four raw materials are close to the ideal protein,and they are all good sources of plant protein with high nutritional value.In terms of functional components,Dendrobium officinale leaves had the highest polysaccharide content(12.93%),and lotus leaves had the highest flavonoid content(124.78mg/g).2.Study on the preparation technology of two kinds of Dendrobium officinale herbal tea.Dendrobium officinale,chrysanthemum and jasmine were used as raw materials to prepare Dendrobium officinale compound scented tea.Based on the comprehensive analysis of polys-accharide and flavonoid content combined with sensory evaluation,it was determined that the best defoliation method of Dendrobium officinale was thermal defoliation at 90℃,and the best drying method was microwave drying.Through mixing design combined with comprehensive analysis,the best ratio of Dendrobium officinale mixed with scented tea was Dendrobium officinale:jasmine:chrysanthemum=5:1:4.Under the conditions of this ratio,the contents of polysaccharide and flavonoids in Dendrobium officinale mixed scented tea infusion were 18.89mg/100m L and 51.27mg/100m L,respectively.The sensory score was92.04 points,and the comprehensive score was the highest,53.51 points.Dendrobium officinale leaves,mulberry,and lotus leaves are used as raw materials to prepare Dendrobium officinale leaves compound teabags.The content of polysaccharides and flavonoids combined with sensory evaluation is analyzed to determine that the best method of curing Dendrobium officinale leaves is microwave curing and the best drying The method is microwave drying,and the best crushing meshes for the three are 60-80 meshes.Through mixing design and comprehensive analysis,the optimal ratio of Dendrobium officinale leaves mixed with tea bags was determined to be:Dendrobium officinale leaves:lotus leaves:mulberry leaves=8:1:1.Under the conditions of this ratio,the contents of polysaccharide and flavonoids in tea brewing solution of Dendrobium officinale compound tea bag were 46.85mg/100m L and11.45mg/100m L,respectively.The sensory score was 87.90 points,and the comprehensive score was the highest,44.09 points.3.Study on the functions of Dendrobium officinale Herbal Tea.The DPPH free radical scavenging rate,superoxide anion free radical scavenging rate,hydroxyl free radical scavenging rate,iron reducing ability and ABTS~+free radical scavenging rate of Dendrobium officinale compound tea reached(73.38%,84.37%,73.91%,absorbance value 1.28,96.92%),respectively.Compared with Dendrobium officinale,DPPH radical,superoxide anion radical,iron reducing ability and ABTS~+radical scavenging ability of Dendrobium officinale were increased by 19.47%,27.13%,1.45times and 21.43%,respectively,but hydroxyl radical scavenging ability was decreased by 11.96%.The inhibitory rates ofα-glucosidase andα-amylase were63.78%and 70.85%,respectively.Compared with the main raw materials,the hypoglycemic ability of Dendrobium officinale compound was slightly decreased(7.43%,19.09%).DPPH free radical scavenging rate,superoxide anion free radical scavenging rate,hydroxyl free radical scavenging rate,iron reducing ability and ABTS~+free radical scavenging rate of Dendrobium officinale composite tea bag reached 39.94%,67.19%,87.93%,absorption value 0.57,52.25%respectively.Compared with Dendrobium officinale,DPPH radical,superoxide anion radical,iron reducing ability and ABTS~+radical scavenging ability of Dendrobium officinale composite tea bag were increased by 17.41%,28.49%,1.58 times and 17.93%,respectively,but hydroxyl radical scavenging ability was decreased by 3.05%.The activity inhibition rates ofα-glucosidase andα-amylase were 43.31%and 21.09%,respectively.Compared with the main raw materials,the hypoglycemic ability of tea making with Dendrobium officinale leaves compound bag was slightly improved(4.27%and 10.29%).4.Quality analysis of Dendrobium officinale herbal tea.The water content of Dendrobium officinale compound herbal tea and Dendrobium officinale leaves compound tea bag were 8.58%and 6.50%,respectively;Ash content was 4.36%and6.03%,respectively.The contents of water extract were 39.63%and 47.90%,respectively.The crude fiber content was 12.71%and 15.40%,respectively.The crude fat content was 5.82%and 5.68%,respectively.Crude protein content was13.44%and 10.54%,respectively.The contents of polysaccharide and flavonoids were 5.53%and 7.88%,53.75mg/g and 25.57mg/g,respectively.The total trace element content of Dendrobium officinale compound scented tea was 484.99mg/kg,and the total trace element content of Dendrobium officinale leaves compound tea bag was 802.92mg/kg.The total free amino acids of Dendrobium officinale mixed with scented tea were 2.72mg/g,and the total free amino acids of Dendrobium officinale leaves mixed with tea bags were 4.16mg/g.The sensory index and hygienic index of the two products meet the national standard requirements of substitute tea.5.Determination and analysis of volatile components in herbal tea of Dendrobium officinale.A total of 112 volatile components were detected in Dendrobium officinale and Dendrobium officinale complex scented tea.73 volatile components were found in Dendrobium officinale,and 77 volatile components were found in Dendrobium officinale complex scented tea.The total relative content of volatile components of Dendrobium officinale was 68.50%,and the total relative content of Dendrobium officinale mixed with scented tea was 72.73%,which was4.23%higher than that of Dendrobium officinale.There were 40 volatile components identical between Dendrobium officinale and Dendrobium officinale mixed scented tea,and 37 volatile components were added after the mixed product.The main flavor volatile compounds of Dendrobium officinale were furfural,methyl heptenone,2,2nonal,styrene,ethyl caproate,5-methylfuran aldehyde,m-xylene,etc.,and the relative contents were 6.64%,4.03%,2.62%,2.35%,1.76%,1.26%,1.04%,respectively.It mainly presents sweet,woody,floral,delicate,fruity and other smells.A total of 98 volatile components were detected in Dendrobium officinale leaves and tea bags made with Dendrobium officinale leaves,there were 65 components in Dendrobium officinale leaves and 67 volatile components in Dendrobium officinale composite tea bags.The total relative content of volatile components in Dendrobium officinale leaves was 55.87%,and the total relative content of volatile components in Dendrobium officinale leaves compound tea bags was 74.43%,which was 18.56%higher than that in Dendrobium officinale leaves.There were 36 kinds of the same volatile substances between Dendrobium officinale leaves and Dendrobium officinale compound tea bags,and 31 kinds of volatile substances were increased after the compound tea bags.The relatively high content of volatile substances in Dendrobium officinale composite tea bag mainly included n-valeraldehyde,1-pentene-3-one,2,4-ditert-butyl phenol,n-octanol,n-octanal,lauryl alcohol,ethyl acetate and so on.The relative contents were 7.34%,7.34%,5.49%,5.12%,2.11%,2.00%,1.89%,respectively.It mainly presents pineapple fragrance,musical fragrance,spicy scent,floral fragrance,fat fragrance and so on. |
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