| Flaxseed( Linum ustitatissimum L.), also known as linseed, was major oil crops and cash crops in northwest of China. Flaxseed and its products play a functional activity depends on a variety of functions ingredient in flaxseed, but many factors can affect the content and structure, as varieties and origin, there was a significant difference of the component content. This paper systematically studied the cultivation of flax varieties of our country representative, a total of 32 species, mainly studied main physical and chemical indicators, variety and nutrition in vitro antioxidant activity of flaxseed and and pressed oil, and analysis correlation antioxidant activity with each micronutrient components, the main findings are as follows:1. Determination physical and chemical quality of the 32 kinds of flaxseed, including water, oil, lignans and its components, sterol and its components, total phenols, tocopherols, etc., there are significant difference in the different varieties, results are as follows:(1) The average moisture content of 32 kinds flaxseed was 6.80 %, crude fat content was 37.80 %; the content of lignans was 14.45 mg SDG equivalent/g defatted flour, SECO was the higher content of lignans after hydrolysis, was 2.60 mg/g seed; the total phenol content of flaxseed was 170.93 mg caffeic acid equivalents/100 g seeds; total sterol content of flaxseed was 92.55 mg/g seed, the highest of the group was β-sitosterol, was 30.35 mg/g seeds; flaxseed contains a small amount of tocopherol, which γ- tocopherol of the total tocopherol content of 96.39 %.(2)The antioxidant activity of the extracts was characterized by DPPH, FRAP, SRSA and ABTS, the average content was 41.18 mg Trolox/100 g seed、0.89 mg Trolox/g seed、1.52 mg Trolox/g seed、24.53 mmol Trolox/g seed, and four antioxidant antioxidant strength sorting system is ABTS> SRSA> FRAP> DPPH.(3)According to the content of each nutrition component of 32 kinds flaxseed, divided into three categories: the first category was the highest content of flaxseed, there were 25 kinds flaxseed; second class indexes content centered, there were six kinds flaxseed; third category of each index was the lowest, only one, was Ningya 17.2. Determination the physical and chemical indicators and nutrition indicators of the 32 kinds cold-pressed flaxseed oil, including acid value, peroxide value, total phenolic, the phytosterols component, tocopherols component, fatty acid composition. For different species, there are significant differences in the content of each indicator.(1) Acid value mean of 32 kinds flaxseed oil was 0.74 mg KOH/g oil, peroxide value mean is 1.11 mmol Na2S2O3/kg, they all meet edible vegetable oil national standards; total phenol content of flaxseed oil was 11.02 mg caffeic acid /100 g oil; flaxseed oil was rich in linolenic acid,the content was more than 45 % of the total fatty acids; linseed oil also contains phytosterols higher, with the highest content was β-sitosterol, 190.35 mg/100 g oil; linseed oil contains less tocopherol, γ- tocopherol which was the main tocopherol content 459.03 μg/g oil in flaxseed oil.(2)The antioxidant activity of the extracts was characterized by DPPH, FRAP, SRSA and ABTS, the result was 3.70 mg TEAC/100 g oil, 5.67 mg TEAC/100 g oil, 0.50 mg TEAC/g oil, 3.80 mmol TEAC/g oil, linseed oil oxidative stability while using the Rancimat method and the DSC method, the oxidation time mean was 5.10 h, the melting temperature and the crystallization temperature were-29.09 ℃(ΔH 20.41 J/g) and-57.32 ℃(ΔH 28.40 J/g).(3) Cluster analysis to classify 32 kinds linseed oil was based on the content of each index, divided into three categories. The first class of all content was the highest of flaxseed oil, there was only 1 kind flaxseed oil; second class indexes content centered mainly 28 kinds of linseed oil; the third category indexes content was low, there were three kinds.3. The flaxseed lignans, total phenols, stigmasterol, total sterols, coumaric acid, SECO, SDG, coumaric acid glycosides significant influence on antioxidant activity(P<0.05); the oxidative stability of the flaxseed oil and the total phenols, the total sterols, α-tocopherol, stigmasterol have a very significant difference, and the oxidation time with stigmasterol has highly significant positive correlation, so stigmasterol was a greater impact on lipid oxidation stability.Because flaxseed and flaxseed oil vitro antioxidant systems influence different components, so there was a difference antioxidant activity sequence, resulting in flaxseed and flaxseed oil antioxidant activity of the antioxidant activity was not consistent. Correlation analysis showed that the oxidation induction time, the results of DSC measurement and antioxidant activity has a positive correlation, but not significant. |
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