Analysis Methods For Pungency Of Chili Pepper And Brine Of Pot-stewed Duck Products

The pot-stewed duck,which is a traditional processed meat product in China,is a popular food item enjoyed by consumers for its unique sauce-flavor.The seasonings such as chili pepper and peppercorn are widely used during pot-stewed process.However,the pungency is usually evaluated only by the workers according to their experience,resulted in the unstable and uncontrollable pungency of pot-stewed duck.Therefore,the quantitative analysis of pungency is necessary during pot-stewed process.The ultrasonic-assisted method was used to extract the capsaicin and dihydrocapsaicin of chili pepper and brine and ultrasonic extraction process was optimized respectively.Then,high perfo rmance liquid chromatography(HPLC)method for analyzing the capsaicin and dihydrocapsaicin of chili pepper and brine was established and the pungency of chili pepper at different varieties and brine at different types were determined to support the standardization manufacture of the pot-stewed duck products.The major results are shown as follows.(1)Chili pepper size,solvent types,ratio of chili pepper to solvent(g/m L),ultrasonic conditions(frequency,temperature,and time),and extraction times are optimized to determine the capsaicin and dihydrocapsaicin of chili pepper.The results showed that the Chili pepper powder with 100 mesh sieve,methanol-tetrahydrofuran solution(60 : 40,v/v),ratio of chili pepper powder to methanoltetrahydrofuran solution(1:10,g/m L),ultrasonic conditions(25 and 40 KHz at the same time,60 ?,and 50 min),and 3 extraction times were preferred.HPLC method was utilized to determine the capsaicin and dihydrocapsaicin of Chili peppers extracted using the preferred ultrasonic-assisted extraction condition.The good linearity was obtained in the range of 0 to 120 mg/L for both capsaicin and dihydrocapsaicin(R2 > 0.98)and the LOD was 2 ?g/g.The RSD of precision and repeatability for capsaicin and dihydrocapsaicin were 1.80% and 2.46%,and 2.53% and 3.80%,respectively.The recovery rate of capsaicin and dihydrocapsaicin w ere 95.57-98.42% and 94.12-98.67%,respectively.The pungency of six kinds of chili peppers was determined using HPLC and sensory evaluation methods,respectively.The Scovill index were 3.91×104,4.04×104,4.42×104,5.84×104,9.39×104,and 3.67×104 SHU for HPLC method and 3.4×104,3.7×104,4.0×104,5.0×104,8.0×104,and 3.1×104 SHU for sensory evaluation method.The pungency of six kinds of chili peppers analyzed using HPLC and sensory evaluation methods were similar.(2)Solvent types,ratio of brine to solvent(g/m L),ultrasonic conditions(temperature,time,and frequency),and extraction times were optimized to determine the capsaicin and dihydrocapsaicin of brine.The results showed that 70% ethanol solution(v/v),ratio of brine to ethanol solution(1:10,g/m L),ultrasonic conditions(60 ?,50 min,and 25 and 40 KHz at the same time),and 3 extraction times were preferred.HPLC method is utilized to determine the capsaicin and dihydrocapsaicin of brine extracted using the preferred ultrasonic-assisted extraction conditions.The good linearity was obtained in the range of 0 to 120 mg/L for both capsaicin and dihydrocapsaicin(R2>0.99)and the LOD was 2 ?g/g.The RSD of precision and repeatability for capsaicin and dihydrocapsaicin were 2.08% and 3.67%,3.52% and 5.58%,respectively.The recovery rate of capsaicin and dihydrocapsaicin was 91.6-97.4% and 90.8-95.3%,respectively.The pungency of five kinds of brine was determined using HPLC and sensory eva luation methods,respectively.The Scovill index were 4.84×104,3.25×104,4.40×104,7.31×104,5.64×104 SHU for HPLC method and 4.0×104,2.4×104,3.1×104,6.0×104,4.5×104 SHU for sensory evaluation method.The pungency of five kinds of brines analyzed using HPLC and sensory evaluation methods were similar.