Study On Characteristic Substances Of Duck Odorous Smell And Deodorization Technology

In recent years,duck meat has become increasingly popular among consumers due to its unique flavor,high nutritional value,and low price.However,the problem of duck odorous smell during processing,distribution,and reheating processes,particularly when consumed,greatly reduces consumers’ desire to purchase it.Currently,there are many research reports on the flavor of duck meat products,but relatively few studies on the composition of duck odorous smell,the causes of duck odorous smell,and deodorization techniques.Therefore,this study focuses on cherry valley duck breast as the research object,using GC-IMS and other technologies to analyze the changes in volatile substances in duck meat after different temperature treatments,storage,and reheating.The main duck odorous smell characteristic substances are identified through sensory and flavor substance evaluation,and the source of duck odorous smell is determined through sensory evaluation.From the perspective of lipid oxidation and lipidomics,this study also explores the relationship between lipid oxidation and duck odorous smell during heat treatment and storage and reheating processes,as well as the differences and changes in lipid composition during this process,further analyzing the precursor substances of duck odorous smell.Finally,this study conducted preliminary research on deodorization techniques for duck meat.The study is divided into three parts,and the main research results and conclusions are as follows:1.The influence of processing temperature and reheating on the duck odor smellUsing electronic nose and headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS)techniques,the volatile components of duck meat processed at 90 ℃,100 ℃,and 105 ℃ were determined before and after 7 days of storage and reheating.The characteristic substances causing the duck odorous smell were identified through sensory and flavor substance evaluations.Results showed that the duck odorous smell increased significantly after 7 days of storage and reheating,and electronic nose results also confirmed differences in odor between different processed samples.HS-GC-IMS identified 60 volatile substances,with similar types but varying relative content among different processing groups.Combining sensory evaluations and relative odor activity values(ROAV)of flavor substances,13 characteristic substances causing the duck odorous smell were identified,including nonanal,octanal,heptanal,decanal,pentanal,hexanal,(E)-2-octenal,(E)-2-nonanal,(E)-2-heptenal,2-methylbutanal,3-methylbutanal,1-octen-3-ol,and 2-pentylfuran.Using orthogonal partial least squares-discriminant analysis(OPLS-DA),9 potential characteristic substances causing the duck odorous smell(VIP>1)were selected to differentiate different processed samples,including nonanal,2-methylbutanal,(E)-2-nonanal,octanal,(E)-2-octenal,hexanal,pentanal,heptanal,and decanal.In addition,sensory results showed that the source of the duck odorous smell was mainly from intramuscular fat.2.Investigating the Impact of Lipid Oxidation on the Duck Odorous Smell during Storage and Reheating based on LipidomicsLipidomic study of the influence of lipid oxidation on duck odorous semll during storage and reheating,to investigate the effects of lipid oxidation on the duck odorous smell during heat treatment and storage and reheating,and to analyze the lipid differences and changes,sensory evaluation was conducted on raw duck meat,90 ℃processed duck meat,and reheated cooked duck meat samples stored at 4±1℃ for 3and 7 days,combined with lipid oxidation-related indicators.The influence of lipid oxidation on the duck odorous smell was analyzed,and a systematic study of lipid changes was conducted on the four groups of duck meat using UPLC-MS technology.The results showed that the duck odorous smell increased after heat treatment and storage and reheating,and during this process,the peroxide value(POV)and thiobarbituric acid reactive substances(TBARS)both increased significantly(p<0.05).The acid value(AV)did not show significant differences after heat treatment at 0 day and reheating after storage for 3 days(p>0.05),but increased significantly thereafter(p<0.05).The conjugated diene value(CD)showed no significant difference after storage for 3 and 7 days followed by reheating.The Raman spectra at 970 cm-1(transdouble bond δ(=C-H)bending vibration),1655 cm-1(carbon-carbon double bond stretching vibration ν(C=C)),and 1745 cm-1(ester bond stretching vibration ν(C=O))peaks reflected the increased degree of lipid oxidation in duck meat after heat treatment and storage and reheating,and the generation of duck odorous smell was closely related to lipid oxidation.Based on lipidomics technology,26 classes of lipid subclasses and519 lipid molecules were identified in duck meat,with phospholipids being an important component.Among the 49 lipid molecules with high VIP values,PC(32:0e),PC(36:5)(rep),LPC(18:0),LPC(20:2),DG(16:0/18:1),MG(18:1),SM(d44:5),and SM(d35:1)were more related to other lipid species.Phosphatidylcholine(PC)and phosphatidylethanolamine(PE)in duck meat phospholipids played an important role in the production of duck odorous smell substances during heat treatment and storage and reheating.In the key differential lipid molecules,fatty acid chains were mainly composed of arachidonic acid(C20:4),oleic acid(C18:1),and linoleic acid(C18:2),which are key precursor fatty acids for the characteristic duck odorous smell.The formation of the duck odorous smell may be due to the oxidative degradation of these lipid molecules.3.Effect of Compound Deodorization Method on Deodorization of Duck Meat and Optimization of Deodorization ProcessTo improve the issue of odorous smell during processing,storage,and reheating of duck meat,a composite deodorizer using ethanol,grape seed extract(GSE),and sodium chloride(Na Cl)was applied to duck breast meat.The deodorization conditions were optimized using a response surface model based on single-factor experiments.The results showed that the optimal conditions for deodorization were 46% ethanol concentration,0.35% GSE concentration,4.3% Na Cl concentration,and a soaking time of 41 min.The deodorization effect was significant under these conditions,and the duck odorous smell was significantly reduced(p<0.05)compared to the untreated group after7 days of storage and reheating.The duck odorous smell decreased by 63.6% after deodorization treatment at 0 days and 60.9% after 7 days of storage and reheating.The acceptability score was 7.00±0.10,indicating good acceptance.The TBARS values of the deodorized duck meat were significantly lower than those of the untreated group at0 days and after 7 days of storage and reheating(p<0.05).The electronic nose effectively distinguished the differences in odor before and after deodorization treatment.Volatile component analysis of the treated duck meat showed a significant decrease in aldehydes after deodorization treatment,including key aldehydes such as nonanal,octanal,heptanal,decanal,2-methylbutanal,3-methylbutanal,(E)-2-octenal,and(E)-2-heptenal,as well as the alcohol 1-octen-3-ol.Therefore,this composite deodorization technology can suppress lipid oxidation in duck meat to some extent,reduce the production of duck odorous smell characteristic substances,and improve the flavor of duck meat.In summary,This study used sensory evaluation,electronic nose,and HS-GC-IMS technology to determine that duck meat processed at different temperatures had a significantly stronger duck odorous smell after 7 days of storage and reheating than at0 days.The main characteristic substances causing the duck odorous smell were nonanal,octanal,heptanal,decanal,pentanal,hexanal,(E)-2-octenal,(E)-2-nonenal,(E)-2-heptenal,2-methylbutanal,3-methylbutanal,1-octen-3-ol,and 2-pentylfuran,with the precursor substances of the duck odorous smell in duck meat mainly derived from intramuscular fat.From the perspective of lipid oxidation and lipidomics,it was shown that the reason for the intensified duck odorous smell after heat treatment and storage reheating was closely related to lipid oxidation,and PC and PE in duck meat lipids played important roles in this process.Key differential lipid molecules containing fatty acid chains such as arachidonic acid(C20:4),oleic acid(C18:1),and linoleic acid(C18:2)may be the key precursor substances causing the duck odorous smell in duck meat.Using a 46% ethanol solution,0.35% GSE concentration,4.3% Na Cl concentration,and a soaking time of 41 minutes as the optimal conditions for deodorizing duck meat,the duck odorous smell in cooked duck meat at 0 days was reduced by 63.6%,and the fishy odor in duck meat stored for 7 days and reheated was reduced by 60.9%,with an acceptance score of 7.00±0.10,which was easy to accept.In addition,this composite deodorization technology can effectively inhibit lipid oxidation in duck meat and reduce the production of characteristic substances causing the duck odorous smell to a certain extent.