| Hippophae rhamnoidesl,belongs to the branch of the decadent,as a kind of medicinal characteristics of the homologous economic cultivation of crops,has the"Divine Fruit Strange Tree"of the name,is an excellent source of nutrition,its growing radiation surface is positive and wide,with high social value,ecological value and medicinal value.Seabuckthorn fruit is rich in the distinctive characteristics of active polyphenols,and continues to be concerned by scholars at home and abroad,with good prospects for development and utilization.As a byproduct of the production and utilization of Seabuckthorn fruit-seabuckthorn seed,the reserves are huge,which is rich in polyphenols active ingredients free phenol and binding phenol,has great research potential.In this study,the extraction and purification process of free phenol and conjugate phenol in Seabuckthorn seed was optimized and preliminarily identified,the antioxidant and bacteriostatic activity in vitro were analyzed,and the effect of compound fresh-keeping liquid with free phenol as main active ingredient on cold fresh meat was discussed,the main contents were as follows:Firstly,the delipidated seabuckthorn seed powder was used as the research object,and the extraction process of free phenol and bound phenol of seabuckthorn seed was optimized by vacuum coupled ultrasonic method and alkali method with polyphenol yield.The extraction process parameters were analyzed with the response surface.The optimal extraction process of free phenol is:extraction solvent is 60%ethanol,ultrasonic power 260 W,liquid-solid ratio 20:1,ultrasonic time 30 min,ultrasonic temperature 52°C,yield 11.394±0.083%;seabuckthorn seed combined with phenol The optimum extraction process was:liquid-solid ratio of 6:1,extraction time of 3.7 h,alkali concentration of 3.5 mol/L,yield of 6.617±0.073%;actual yield and response surface prediction of two kinds of polyphenols from seabuckthorn seeds The values are basically the same.Secondly,the extracted polyphenols were purified by macroporous resin method,and the components of polyphenol extracts were identified by color reaction,UVscanning and infrared scanning.Among the 8 alternative resins,HPD826 resin is the best for purifying free phenol,and AB-8 resin is the best for purifying seabuckthorn seed combined with phenol.The optimal loading concentration in the purification process was 3.2 mg/mL,the loading flow rate was 2 BV/h,the eluent concentration was 75%,the elution flow rate was 1.5 BV/h,and the phenol 2 BV/h was combined.It is 37.88%and 34.16%.The purified free phenol and the combined phenol color reaction were positive,indicating that the purified substance was a phenolic substance;the UV scanning at 190-400 nm showed that there were two kinds of phenolic protochrome characteristic band at 270 nm.The characteristic peaks appeared in the extracts.The results of infrared scanning showed that the polyphenol extract of seabuckthorn seeds may have benzene ring skeleton structure,and the main structure may be the original.Thirdly,the in vitro antioxidant activity of purified polyphenols was detected by spectrophotometry.The antibacterial activity of seabuckthorn seed polyphenols was observed by perforation method,double dilution method and agar plate method.The results showed that seabuckthorn seed polyphenols on DPPH free radicals(1,1-diphenyl-2-trinitrophenylhydrazine free radical),ABTS free radicals(2'-hydrazine-bis-3-ethylbenzothiazole The scavenging rate of porphyrin-6-sulfonic acid free radical is close to that of Vc(P>0.05);it also has good antioxidant capacity against hydroxyl radical,superoxide anion and nitrite.The concentration of 1g/mL seabuckthorn seed free phenol and combined phenolic samples have good antibacterial effect against Staphylococcus aureus.The diameter of the inhibition zone is 30.54±0.53 mm and 22.18±0.04 mm respectively.Pseudomonas aeruginosa Common rot fungi such as Bacillus subtilis,Salmonella,and Escherichia coli also exhibit certain antibacterial efficacy.The MIC of seabuckthorn seed free phenol to Staphylococcus aureus was 0.25 mg/mL,and the remaining test bacteria were 0.5mg/mL;the MIC of seabuckthorn seed combined with phenol was 0.5 mg/mL for each test strain.It is suggested that seabuckthorn seed free phenol and bound phenol have strong antioxidant capacity and bacteriostatic performance,and the effect of free phenol is better.Fourthly,based on the free phenol extract of seabuckthorn seed,the single factor design and orthogonal test were used to screen the best composite fresh-keeping liquid ratio,and the fresh-keeping effect on cold meat was explored.The optimal ratio of the composite fresh-keeping liquid obtained by screening was:seabuckthorn seed free phenol 2.5%,chitosan 2.25%,V_E 0.15%.This formula was used for fresh meat preservation.The results showed that the meat samples treated with the composite fresh-keeping liquid did not deteriorate at the 9th day of storage.The sensory score,total number of colonies and TVB-N were 5.26±0.30 and 5.8±0.17 log cfu/mL,19.5±0.72 mg/100g,in line with the national health standard for cold meat,the fresh-keeping effect is slightly lower than 2.5%in the tea polyphenol treatment group(P>0.05),while the untreated meat sample is stored at 4°C.d markedly deteriorated.Compared with the blank control group,the pH value of the composite fresh-keeping liquid treated on the 12th day of storage was 6.09±0.15(P<0.05),which still met the national first-class fresh meat standard;the meat-like shear force was 3.32±0.16 kg,significantly higher than the blank control;the drip loss rate was significantly lower(P<0.05),which was 3.22±0.06%;the difference of cooking loss rate between the groups was not significant(P>0.05);The fresh-keeping effect was basically the same as that of the 2.5%tea polyphenol treatment group.In summary,the extraction and purification process of seabuckthorn seed free phenol and bound phenol is reliable.The main structure of the seabuckthorn seed is the original Cuiqueding,which has good antioxidant activity and antibacterial activity in vitro.At 4°C,seabuckthorn seeds The composite fresh-keeping liquid composed of free phenol,chitosan and V_E can prolong the shelf life of chilled meat and maintain the meat quality. |
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