Effects Of Tamarix Ramosissima Bark Extract From Xinjiang On The Edible Quality And Heterocyclic Aromatic Amines Formation In Roast Lamb Patties

For hundreds of years,Tamarix was used for roasting lamb skewers and the traditional medicine of Uyghur and Kazakh.Inspired by Chinese traditional culture,the effects of Tamarix on the sensory attributes and safety of roast lamb were investigated deeply and it is of great historical and practical significance to develop Chinese traditional culture and healthy China.Tamarix ramosissima,which has been widely planted in southern Xinjiang,was used as the object of this research,the major polyphenolics compositions,the antioxidant and antibacterial activities of Tamarix ramosissima bark extract(TRE)were firstly studied and then the sensory attributes and safety of TRE on roast lamb were studied.In particular,the inhibitory mechanisms of TRE and its three major polyphenolics on the heterocyclic aromatic amines(HAs)formations in roast lamb were deeply explored.These results can provide the theoretical basis for inhibiting HAs formation during thermal processing of meat products.The research contents and results are as follows:1.The major polyphenolics compositions,the antioxidant and antibacterial activities of TREThe TRE polyphenolics were extracted by ultrasound-assisted extraction and the optimal technique conditions were obtained,with a solid to liquid ratio of 1:20,71.2%(v/v)ethanol,and a ultrasound powder of 750 W.Under the above-mentioned conditions,the TRE polyphenolics content was 323.45 mg/g,and total flavonoids content was 87.32 mg/g.According to Ultra performance liquid chromatography/tandem mass spectrometry(UPLC-MS/MS),A total of 13 polyphenolic compounds were identified,in which isorhamnetin(36.91?g/mg),hispidulin(28.79?g/mg),cirsimaritin(13.35?g/mg),and quercetin(4.21?g/mg)were the four most abundant compounds,and,for the first time,hispidulin and cirsimaritin were isolated from the genus Tamarix.The extract exhibited promising antioxidant activity with IC50 values of 117.05 ?g/mL for 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical scavenging activities,as well as excellent reducing power with an EC50 of 93.77 ?g/mL.The TRE showed appreciable antibacterial properties against foodborne pathogens.Listeria monocytogenes was the most sensitive microorganism with the lowest minimum inhibitory concentration(MIC)value of 5 mg/mL and minimum bactericidal concentration(MBC)value of 10 mg/mL followed by Shigella castellani and Staphylococcus aureus among the tested bacteria.The TRE showed significantly stronger inhibitory activity against Gram-positive than Gram-negative bacteria.2.Effects of TRE on meat quality and flavor of roast lambTRE was added to roast lamb patties for exploring the effects on moisture content,water holding capacity,tenderness,color,texture,protein and lipid oxidation,as well as flavor characteristics of roast lamb,and then combined with sensory evaluation,an overall evaluation was obtained.The results showed that,with the additions of TRE at different levels,moisture content was significantly increased(P<0.05),while the cooking loss decreased significantly,indicating TRE improved the water holding capacity of roast lamb.After roasting for 25 min and 35 min,the shear force values of TRE treatments were significantly lower than the control group(P<0.05),suggesting TRE can improve the tenderness of roast lamb.With the increasing TRE additions,both L*and b*values tended to decrease while an increase was found for a*value of roast lamb.TRE at the levels of 0.30 and 0.45 g/kg significantly reduced the hardness of roast lamb(P<0.05),and when roasting for 15,25,and 35 min,the hardness of TRE at 0.45 g/kg decreased by 32.64%,28.08%,and 9.12%,respectively.The carbonyl content and TBARS values showed a significant decrease with the increasing TRE levels(P<0.05),and the total thiol content showed a significant increase(P<0.05),indicating the higher of the TRE adding levels,the lower of the degrees of protein and lipid oxidation.An obvious raise was observed in the total species and contents of flavor substances with the adding of TRE.The varieties of hydrocarbons and esters also increased while TRE had no significant impact on the species of alcohols,ketones and heterocyclic compounds.Sensory evaluation results showed that the addition of TRE had no significant influence on color,tenderness,and overall acceptability(P>0.05),while the flavor scores significantly increased(P<0.05),indicating that the addition of TRE didn't adversely affect the sensory quality of roast lamb,but giving a better flavor taste.3.Effects of TRE on hazardous substances formations and their precursors contents in roast lambTRE was added to roast lamb patties for exploring the effects on HAs and Polycyclic aromatic hydrocarbons(PAHs)formations,and also for detecting the changing of their precursors contents in roast lamb.The results showed that TRE at all the three adding levels significantly decreased the formations of PhIP,IQ,MeIQ and MeAaC(P<0.05).The treatment with the highest inhibition rate was TRE at 0.30 g/kg and roasting for 15 min(71.67%),followed by the treatment of TRE at 0.45 g/kg and roasting for 25 min(70.83%).As a whole,TRE exhibited effectively inhibitory capabilities on the formation of total HAs,polar HAs,and 4 HAs identified by International Agency for Research on Cancer(IARC)as carcinogenic.In practice,using total HAs as the evaluation indicators,0.15 g/kg TRE was suitable for the lamb patties roasting for 15 min,and 0.15 g/kg TRE was for more than 25 min.For the PAHs,no benzo(a)pyrene was detected in all the treatments(below the minimum quantitation limit of 0.5 ?g/kg).These results showed that TRE effectively inhibited the formation of HAs in roast lamb and can be potentially used in inhibiting the hazardous substances formations of meat products.With regard to precursor,the glucose concentrations of TRE at 0.15 and 0.45 g/kg treatments significance higher than the control group at three roasting time(P<0.05),while the creatinine contents showed a tendency to significant reduce as the increasing adding levels of TRE(P<0.05).All the free amino acids concentrations significantly decreased after roasting with the ratio of 22.26%to 77.18%.The addition of TRE had a slow down effect on the consumption of free amino acids,especially for Asp,Thr,Ser,Phe,Lys,His,and Arg.The results indicated that TRE inhibiting HAs formation in roast lamb was closely related to the different precursors in lamb.4.Mechanism of TRE inhibiting HAs formationTaken PhIP as the research object,the effects of TRE and its three major polyphenolics,isorhamnetin,hispidulin,and cirsimaritin,on the PhIP formations in chemical model and roast lamb patties were studied,and the possible mechanisms of these substances inhibiting PhIP formation were explored.The results showed that,the PhIP formations both in chemical model and roast lamb patties were significantly inhibited by the four additives at three adding levels(P<0.05),furthermore,the inhibition of TRE,isorhamnetin,and hispidulin on PhIP formation were dose-dependent manner.In the roast lamb patties,the concentrations of PhIP were 0.36,0.24,and 0.14 ng/g at the TRE levels of 0.15,0.30,and 0.45 mg/g,with the corresponding inhibition rates of 25.00%,50.00%,and 70.83%.The strongest inhibition was found at 0.45 mg/g TRE treatment with a ratio of 70.83%,followed by isorhamnetin at 18.0 ?g/g with a inhibitory ratio of 69.82%.With regard to the chemical systems,there were some differences in the inhibition of 3 polyphenolics on PhIP formation.The PhIP generation decreased significantly with the increasing of TRE levels(P<0.05),while no significant difference was found among the different adding levels of cirsimaritin(P>0.05).The highest inhibition activity were at 37.5 and 25.0 mg/mL of TRE treatments with the ratios of 72.85%and 69.11.which were significant higher than other groups(P<0.05).Compared to the control,all the four additives significantly reduced the concentration of-phenylacetaldehyde in model systems(P<0.05).The residual phenylacetaldehyde in different treatments were ranging from 0.02 to 0.14 mmol/L and the scavenging activities of four additives on phenylacetaldehyde increased with increasing levels.TRE exhibited the strongest scavenging activities and the scavenging ratios at three different adding levels were 87.54%,82.16%,and 86.57%,without significant difference among the three levels(P>0.05).Correlation analysis results showed that there were good relations between the phenylacetaldehyde-scavenging activity with PhIP inhibition of TRE,isorhamnetin,and hispidulin in chemical models and roast lamb.TRE and isorhamnetin had very significantly positive correlations(P<0.01)and hispidulin had a significantly positive correlation(P<0.05),while cirsimaritin had a poor correlation(P>0.05).The polyphenolics can inhibit PhIP formation via reacting with phenylacetaldehyde to form the corresponding adducts.In the present study,three polyphenolics-phenylacetaldehyde were obtained from chemical model systems,named 8-C-(E-Phenylethenyl)isorhamnetin,6-C-(E-Phenylethenyl)isorhamnetin,and 8-C-(EPhenylethenyl)hispidulin.UPLC-MS/MS and Collision-induced dissociation(CID)were used for further identification and the results confirmed that the adducts at m/z 419 and 403 mostly resulted from the electrophilic substitution of phenylacetaldehyde on the A ring of isorhamnetin at the C-6 or C-8 positions and hispidulin at the C-8 position,while under the same reaction conditions,no direct adduct between cirsimaritin and phenylacetaldehyde were found in the system.These results confirmed that the inhibitory effects of TRE,isorhamnetin,and hispidulin on PhIP formation were mainly attributed to the trapping of phenylacetaldehyde in chemical models and roast lamb but the mechanism underlying the inhibitory effects of cirsimaritin is not completely understood.In conclusion,the mechanism of TRE inhibiting HAs formations was mainly due to the polyphenolics-phenylacetaldehyde adducts formation in roast lamb patties.