| Meat and meat products are indispensable sources of nutrients in people’s daily diet.Heat-processing can greatly improve the nutritional value and sensory quality of meat,meanwhile,it could lead to the formation of heat-driven hazards,such as polycyclic aromatic hydrocarbons,heterocyclic aromatic amines,advanced glycosylation products.Polycyclic aromatic hydrocarbons(PAHs)present hydrocarbons with more than two benzene rings,among which benzo(a)pyrene is the representative carcinogenic substance that is widely studied.The formation mechanism of PAHs is still unclear,and it is believed that they are formed via reaction of pyrolysis and pyrosynthesis involved with free radicals.Many studies showed that PAHs could produce and accumulate in the meat during barbecuing,smoking,frying etc.Therefore,how to minimize the intake of hazards,meanwhile satisfying the appetite of consumers is a challenge for the meat product industry.Recently,the natural phenolic-rich extracts have been a hotspot for mitigating the hazards in meat products.Therefore,the present study took the Nanjing roast duck,a kind of traditional barbecue meat product as example,the details and outcomes are as follows:1.The PAHs content and analysis in commercial Nanjing roast duck.Take the electronic-roasting duck as the control,the content of PAHs in skin and meat part of the Nanjing roast ducks were investigated.And the p H value,moisture content and fat content of roast duck samples were also measured.The results showed that the PAH8 in Nanjing roast duck skin was relatively high ranging from 10.11-25.18 ng/g,which was significantly higher than that in control group.The PAH8 in duck meat samples was 0.84-2.29 ng/g,which was slightly higher than that in the control group with no significant difference calculated.The content of PAH8 in duck skin of all samples is significantly higher than that in duck meat,so the duck skin sample could represent the profiles of PAHs in Nanjing roast duck.The profiles of PAHs in roast duck samples were visually analyzed by principal component analysis(PCA).The results revealed that the content and distribution of PAHs in different roast duck were not consistent.Ch、Bb F and Dh A are the main contributors to the different profiles amongst roast duck samples.On the other hand,the outcomes of Pearson correlation analysis indicated the content of PAHs in roast duck was negatively correlated with water content,positively correlated with fat content and had no correlation with p H value.2.The effect of coriander extract marinade on the formation of PAHs in roast duck.Given the relatively high content of PAHs determined in Nanjing roast duck,so the natural phenolic-rich extract was chosen for mitigating the PAHs in roast duck.200,400,600,800 and 1000 mg/L of coriander root and leaf marinades were prepared respectively.The duck wings were marinated in these two marinades and then charcoal roasted.The total phenolic content(TPC),DPPH· scavenging activity and ferric reducing power(RP)before and after marinating,PAHs and total free radical level were determined.The results showed that TPCs of coriander leaf and root before marinating was 11.4-29.2 mg GAE/L and 5.4-9.7mg GAE/L,respectively and decreased in both marinades after marinating.Coriander leaf marinade exhibited stronger DPPH· scavenging activity and RP than those in root marinade before and after marinating.Both marinades effectively reduced PAHs in roast duck wings.Coriander root marinade showed better inhibitory effect on the formation of PAH8 by 65.0-87.4%,as well as 16.6-51.8% of PAHs in leaf marinated samples.In addition,the level of free radicals in roasted duck wings was detected by electron spin resonance spectrometer.The results indicated that the free radical intensity of roasted duck wings marinated by coriander root was lower than that in the leaf marinade,and there was a significantly positive correlation between the content of PAHs and the free radical intensity,which indicated that free radicals might participate in the formation of PAHs.It was speculated that phenolic components in coriander extract could act as free radical scavengers or metal ion chelating agents to interfere the reaction transmission chain of free radical,resulting in reduction of PAHs in roasted duck wings.And further study will be needed to investigate the specific phenolic compositions which played a key role in inhibiting the formation of PAHs.3.The effect of phenolic compounds in coriander extract marinade on the formation of PAHs in roast duck.The phenolic components of coriander root and leaf marinades were identified by LCMS/MS system to select the specific phenolic compounds that may contribute to the inhibitory effect on PAHs formation according to the response value.The selected phenolic compounds were used to marinate the duck wings in different concentrations.After charcoal roasting,the profiles of PAHs was detected in the roasted duck wings.The DPPH· scavenging activity and ferric reducing power were also determined before and after marinating.A total of 20 and 16 phenolic compounds were identified respectively in the coriander root and leaf marinades,and Naringin,Vanillic acid,Protocatechuic acid and Kaempferol were selected from coriander root marinade.DPPH· scavenging activity and RP of four phenolic compounds marinades with different concentrations showed significant concentrationdependent effects.The antioxidant activities of Vanillic acid and Protocatechuic acid at the same concentration were significantly higher than those of Naringin and Kaempferol.All the four phenolic compounds effectively reduced the content of PAHs in roast duck wings,by29.6-72.6% and 32.2-70.6% of Naringin and Vanillic acid,respectively.The inhibitory effect of Kaempferol was significantly higher than that of Protocatechuic acid,which ranged from52.8-81% and 41.5-72.6%,respectively.It seemed that the inhibitory effect of different phenolic compounds on PAHs formation has weak correlation with their antioxidant activities.The Pearson correlation analysis indicated the clear dose-effect between Vanillic acid,Naringin,Protocatechuic acid and content of PAHs,while weak correlation between Kaempferol and PAHs.Therefore,it was speculated that different phenolic compounds may inhibit the formation of PAHs in different ways.The pathway of free radical scavenging may not be the only mechanism for phenolics to reduce the PAHs formation,it may also be related to Maillard reaction pathway. |
