Study On Pigments Of Fruit From Lycium Ruthenicum Murr.in Qinghai Province

Lycium ruthenicum Murr.belongs to Solanaceae,with a variety of functional components,including natural plant pigments-anthocyanins.Because of various biological activities shown by current studies,it has certain research and application value.In this paper,a systematic study was carried out about the extraction,purification,physicochemical properties and component analysis of the pigments in Lycium ruthenicum Murr.It is expected to provide reference for the deep processing and application of the fruit resources of Lycium ruthenicum Murr..The main results are as follows:1.The dried fruit of Lycium ruthenicum Murr.was used as raw material,the content of basic and functional components was analyzed and determined.The contents of basic components such as water,ash,crude fat,total acid and total protein were 11.87±0.46%,4.26±0.23%,4.16±0.12%,18.17±0.17%,and 11.54±0.02%,respectively.Meanwhile,the content of neutral polysaccharide was 19.24±0.92 mg/gDW,acidic polysaccharide was14.91±3.31 mg/gDW,total anthocyanin was 3.87±0.05 mg/gDW,total polyphenol was36.96±1.80 mg/gDW,total flavonoid was 59.13±1.08 mg/gDW.2.By the experiments of single factor and response surface analysis,the extraction process parameters of pigment were optimized.The acidified ethanol method was used as the pigment extraction method,which ethanol concentration was 70%,the ratio of material to liquid was 1:20?g:mL?,the extraction time was 2 h,and the extraction temperature was 40°C.3.The adsorption capacity,adsorption and desorption rates of three macroporous resins,such as AB-8,X-5 and D-101 were discussed on the pigments of Lycium ruthenicum Murr.,and the D-101 resin with the best purification effect on the pigment was selected and the treatment method of the resin was determined.D-101 macroporous resin was selected for the static adsorption and dynamic desorption condition research in the pigments.The results showed that wet resin of 1 L could adsorb 180 g-220 g of dried fruit extract and the adsorption time was 3-10 min,70-80%ethanol was the best elution system.The flow rate of ethanol was0.3-0.5 BV/h,and the flow rate was 1.5-2.0 BV.Under this parameter,the color scale of the pigment could reach 121.183,and the purification multiple was 39.863.4.The stability and antioxidant activity of the pigments of refined Lycium ruthenicum Murr.showed it had a certain heat resistance under the condition of pH?3,and the poor thermal stability at pH>3.0.The change of light condition in a short time had little effect on the stability of pigment.The resistance to redox of the pigment was poor.The commonly used food flavoring agents such as malic acid,citric acid,and tartaric acid was inoperative on the stability of the pigment,but the coloring effect increased with the concentration of the organic acid.Obviously;metal ions?10 mmol/L?such as K⁺,Na⁺,Ca²⁺,Mg²⁺,Zn²⁺hardly affected the stability of pigment structure,Cu²⁺,Al³⁺,Fe³⁺destroyed the stability of pigment structure,while Fe³⁺has color enhancement effect in a short time.The determination of DPPH·,ABTS⁺and FRAP values indicated that the refined pigments of Lycium ruthenicum had strong antioxidant capacity.5.HPLC and LC-MS were used to preliminarily study on the refined pigment components of Lycium ruthenicum Murr.Five anthocyanin structures were identified,and four of them were petunidin derivatives and one was malvinidin derivative.