Pungency And Quality Attributes Of Pot-Stewed Duck During Marinating

Pot-stewed duck is a traditional meat product prepared with marinating process in China.It is also a cooked meat product prepared by heating the blends with duck meat,spices and seasonings,and water.Pot-stewed duck products with a unique flavor and instant characteristics are very popular food items for consumers.The spices and seasonings,salt,and other accessories need be added to brine in batches during marinating process of pot-stewed duck since they are absorbed by duck meat and evaporated by heating.Moreover,the quality of recycled brines and the loss of auxiliary materials can’t be quantified and the process parameters are only controlled by experienced workers,resulting in the varying flavor of pot-stewed duck products.Therefore,it is necessary to measure quantificationally the pungency and quality attributes of pot-stewed duck products and brines.In the work,ultrasound-assisted method was used to extract capsaicin and dihydrocapsaicin in the pot-stewed duck products.The ultrasonic pretreatment process was optimized to establish the analysis method for pungency of pot-stewed duck products during marinating.Furthermore,the pungency of pot-stewed duck products and brines and the sensory quality of pot-stewed duck products was measured to investigate the correlation between the pot-stewed duck and brine pungency.The work will provide technical guidance for the standardization of the marinating process of pot-stewed duck products.The main results and conclusions are as follows:1.Pretreatment conditions optimization of HPLC methods for the pungency analysis of pot-stewed duck products.The ultrasonic-assisted method was used to extract the capsaicin and dihydrocapsaicin in pot-stewed duck products,and the effect of solvent types,ratio of duck meat to solvent,and ultrasonic conditions(time,frequency,and extraction times)on the yield of capsaicin and dihydrocapsaicin was investigated to optimize the pretreatment conditions of HPLC method for the pungency analysis.The results showed that the pretreatment conditions with 60%of ethanol solution,1:30 g/mL of duck meat to ethanol solution,and double frequency ultrasonic conditions(20 min,25 and 40 KHz,and 2 times)was preferred.The detection limit(0.01 mg/mL),The RSD of precision and repeatability for capsaicin and dihydrocapsaicin were 0.99%and 4.76%,1.48%and 9.52%,respectively.The recovery rate of capsaicin and dihydrocapsaicin were 90-94%and 90-93%,respectively.The pungency of six kinds of pot-stewed duck products was measured using HPLC and sensory evaluation methods,respectively.The Scoville index were8.9×10~4,6.7×10~4,9.3×10~4,1.0×10~5,8.1×10~4,and 7.5×10~4SHU for HPLC method and8.8×10~4,6.5×10~4,9.0×10~4,1.0×10~5,8.0×10~4,and 7.5×10~4 SHU for sensory evaluation method.The pungency of six kinds of pot-stewed duck products was similar,which was analyzed by using HPLC and sensory evaluation methods.2.The pungency and sensory quality of pot-stewed duck during marinating.The on-line samples of pot-stewed duck products and brines(different batches,marinating times,and brine formulas),which were gained from a food company in Hubei province,were used to measure the pungency of pot-stewed duck products and brines and the sensory quality of pot-stewed duck products.The correlation between the pot-stewed duck products and brines pungency was also investigated.The results showed that there was a significant difference in the pungency of pot-stewed duck products and brines between 1st,2nd,and 3rd batches.The contents of capsaicin and dihydrocapsaicin in the pot-stewed duck neck were 3.39 mg/g and 0.11 mg/g,4.32mg/g and 0.12 mg/g,and 5.23 mg/g and 0.24 mg/g,and those in brines were 10.79mg/g and 0.28 mg/g,8.91 mg/g and 0.29 mg/g,and 8.91 mg/g and 0.29 mg/g.Similarly,the contents of capsaicin and dihydrocapsaicin in duck wing were 3.13mg/g and 0.11 mg/g,4.22 mg/g and 0.13 mg/g,and 5.26 mg/g and 0.22 mg/g,and those in brine was 7.52 mg/g and 0.51 mg/g,10.49 mg/g and 0.54 mg/g,and 9.10mg/g and 0.61 mg/g,indicating that the marinating batches had an obvious effect on the pot-stewed duck products.In addition,the obvious differences in shear force and color of pot-stewed duck products between 1st,2nd,and 3rd batches were observed,indicating that the marinating batches affected the sensory quality of pot-stewed duck products.The correlation and variance analysis of pot-stewed duck products and brines pungency with different batches was performanced.The Pearson coefficients were 0.340(duck neck)and 0.554(duck wing),respectively,and the absolute value was greater than 0.1,indicating that there is a positive correlation between pot-stewed duck products and brines pungency.The contents of capsaicin and dihydrocapsaicin in pot-stewed duck neck obviously increased from 2.16 mg/g and 0.06 mg/g to 3.89 mg/g and 0.14 mg/g with an increase of marinating times from 10 min to 50 min,respectively.Afterwards,a slight increase was presented and the contents of capsaicin and dihydrocapsaicin were only 4.57 mg/g and 0.17 mg/g until 70 min.Those in brines increased from 6.11 mg/g and 0.32 mg/g to 7.01 mg/g and 0.48 mg/g during 10 and 50 min,respectively.After50 min,a slight increase was presented.When the marinating times increased from 10min to 40 min,the contents of capsaicin and dihydrocapsaicin in pot-stewed duck wing increased from 2.08 mg/g and 0.05 mg/g to 3.63 mg/g and 0.13 mg/g,respectively,and those in brines increased from 6.23 mg/g and 0.33 mg/g to 7.23mg/g and 0.48 mg/g,respectively.In addition,the shear force of pot-stewed duck products decreased gradually with an increase of the marinating times,decreasing from 31.17 N to 22.36 N(duck neck)and 32.58 N to 20.18 N(duck wing),respectively.L*value significantly decreases,and a*and b*values heavily increased,indicating that the marinating time obviously affected the pungency of pot-stewed duck and brine as well as the sensory quality of pot-stewed duck products.The correlation and variance analysis of pot-stewed duck products and brines at different marinating times was performanced.The Pearson coefficients were 0.948(duck neck)and 0.995(duck wing),respectively,and the absolute value was greater than 0.1,indicating that there is a positive correlation between pot-stewed duck and brine pungency.Formulas A and B for brines were used to prepare pot-stewed duck products.The contents of capsaicin and dihydrocapsaicin in the pot-stewed duck neck were 3.30mg/g and 0.13 mg/g,and 3.80 mg/g and 0.16 mg/g,respectively,and those in brines were 8.27 mg/g and 0.31 mg/g,9.59 mg/g and 0.48 mg/g.Similarly,the contents of capsaicin and dihydrocapsaicin in the pot-stewed duck wing were 2.83 mg/g and 0.10mg/g,and 3.33 mg/g and 0.13 mg/g,and those in brines were 6.88 mg/g and 0.22mg/g,and 7.95 mg/g and 0.41 mg/g,indicating that the brine formulas had an obvious effect on the pungency of pot-stewed duck products.The shear force of pot-stewed duck neck with formulas A and B for brines were 25.52 N and 24.81 N,respectively,and those for duck wing were 23.21 N and 24.48 N,respectively,indicating that there is a slight effect of brine formulas on the shear force of pot-stewed duck products.Compared with formula A for brine,there was no obvious difference in L*value between pot-stewed duck neck and duck wing with formula B,and a significant increase of a*and b*values was presented,respectively,indicating the yellowness and redness of pot-stewed duck products(formulas B)were higher than Formula A.The correlation and variance analysis of pot-stewed duck products and brines with different formulas was performanced.The Pearson coefficients were 0.993(duck neck)and 0.997(duck wing),respectively,and the absolute value was greater than 0.1,indicating that there is a positive correlation between pot-stewed duck products and brine pungency.