Extraction And Application Of Proanthocyanidins From Highland Barley

Highland barley（Hordeum vulgare L.var.nudum Hook.f.）,belongs to the genus Barley of Gramineae.Because of the separation of grain and caryopsis,and the grain is exposed to the outside,it is also called naked barley,which is a food crop with national characteristics in Qinghai-Tibet Plateau.In other areas,it is also known as hulless barley,rice wheat,naked wheat,naked barley and barley.It is a plant of the Gramineae and also a variety of barley.Highland barley is one of the most important cereal crops in the plateau,which has the characteristics of early maturity,cold tolerance and wide adaptability.,and it is also an iconic plant on the Qinghai-Tibet Plateau.Because of its own health care and medicinal value,it becomes the most advantageous natural health ecnomic crops in the Qinghai-Tibet Plateau.In recent years,people have found that the procyanidin contained in highland barley is a kind of substance which can fight cancer,resist fatigue,and is beneficial to the cardiovascular system.Moreover,the production of highland barley is large,most of which are used as raw materials for grain and beer industry.So far,the rare reports on the proanthocyanidins of highland barley have been reported,so our team has carried out a systematic and in-depth study on highland barley,and designed the experimental scheme to determine the best technology for extracting the procyanidin from the industrial production of highland barley.Then screened out the best purification condition and carried on the preliminary separation.which used ultra-high performance liquid chromatography to identify its components and was applied in daily life.The aim was to provide a theoretical basis for the comprehensive development of highland barley and the comprehensive utilization of science and technology.The main research contents are as follows:（1）The quality standards of ash and moisture of different varieties of highland barley from different producing areas were evaluated,and the active substances in highland barley were compared and analyzed.Results:The contents of ash,moisture and extract in different highland barley from different producing areas were certainly different,which all met the standard of Pharmacopoeia.The same to active ingredients,the white barley proanthocyanidin content in Shigatse area of Tibet was the highest,5.77%,the black barley flavonoids content was the highest in Qinghai Beihai area,0.34%,whose polyphenol content was also the highest,3.44%;（2）White highland barley in Shigatse area of Tibet was taked as raw meterial,which was based on single factors of methanol concentration,ratio of material to liquid,extraction time and extraction temperature,the process of ultrasonic assisted extraction of procyanidins was discussed by using response surface analysis.The majorizing process conditions were as follows:The methanol concentration is 66%,the ratio of material to liquid was 1:22,the extraction time was 32 min,the temperature was 56℃,and the yield was 4.95%;（3）Five different kinds of resins as D-101,AB-8,HPD-100,HPD-300,NKA-9were choosen to investigate the desorption effect of proanthocyanidins and the length of the desorption equilibrium time effects of procyanidins solution adsorption and desorption equilibrium time.Through Comprehensive consideration,the AB-8 was choosen as the best resin purification of proanthocyanidins from barley,the adsorption rate was 85.89%,the adsorption equilibrium time was 2h,the desorption rate was 98.64%,and the desorption equilibrium time was 45 min.The yield of proanthocyanidins purified by AB-8 resin was 1.23%,and the purity was 93.79%.In which the purity of proanthocyanidin was 6.8 times higher than that of the unpurified extract;（4）A series of experiments of thin layer chromatography were carried out to investigate the optimal expansion system of barley procyanidin in which V（Ethyl acetate）:V（Acetone）:V（Formicacid）:V（Water）=5:1:1:1.Three chromatographic bands were obtained.Three chromatographic bands were detected by UPLC and analyzed preliminarily.The result was that the first chromatographic band contains catechins and epicatechins,and the other two need to be further studied;（5）Through the DPPH·and ABTS⁺free radical scavenging and Fe³⁺reduction of antioxidant experiment in vitro,the antioxidant capacity of three different kinds of barley procyanidin in Shigatse area of Tibet were investigated.The results showed that the antioxidant capacity of black barley was the strongest,the black barley samples in the experimental maximum concentration on DPPH·radical scavenging rate was 83.92%,the scavenging rate ABTS⁺free radical rate reached 92.52%,and the determination value of iron ion reducing ability was 1.099;（6）The stability of proanthocyanidins to vario,us environmental factors,including light,pH,temperature,metal ions,oxidantsreducing agent and food additives,was investigated.Conclusiont:The procyanidin of highland barley should be stored under 40℃and avoid contact with Cu ²⁺Fe²⁺and oxidants.During storage,suitable amount of reducing agent and food additives could be added to them to prolong the storage time.paste without stratification,no discoloration and no pan-coarseness phenomenon;（7）The quality standard of highland barley procyanidin was investigated after it was made into cream.Through sensory evaluation,physical and chemical index test and methodology investigation,it was concluded that the barley procyanidin cream made by our team had no allergy which also had good sense of use with stable nature,content of catechin determined by UPLC in highland barley procyanidin cream was2.71 mg/mL,and the content of epicatechin was 1.77 mg/g.