Changes Of Biogenic Amines And Physicochemical Indexes Of Chili-horsebean Paste During Fermentation

Sichuan cuisine is one of the famous dishes in China due to its excellent color and flavor,which is inseparable from the seasoning effect of pixian chili-horsebean paste used in the production process.Pixian chili-horsebean paste sauce is widely favored by consumers due to it has the advantages of sticky sauce with good taste,strong fragrance,mild spicy.So it enjoys the reputation of“the soul of sichuan cuisine”.Pixian chili-horsebean paste is semi-flowing viscous or semi-solid flavoring product.The dried broad beans and fresh red pepper was the main raw materials of pixian chili-horsebean paste,the paste was always fermented for a certain period of time.Currently,the researches on pixian chili-horsebean paste mainly involve analysis like volatile flavor,microbial diversity during natural fermentation,microbial co-culture enhancement technology to shorten fermentation time,etc.But the types and content of biogenic amines in pixian chili-horsebean paste and factors that affect biogenic amine producting have been less studied.A small amount of biogenic amines can regulate the normally physiological functions of human body,but excessive consumption will cause health problems.With the increase of people’s demand for safe food and the realization that there may be excess biogenic amines in traditional fermented foods,so the biogenic amine content and types in pixian chili-horsebean should be efficiently detected.The object of this paper was to evaluate the biogenic amines content of pixian chili-horsebean paste with high-performance liquid chromatography dansyl chloride derivative method.The optimal sample pretreatment method was determined by optimizing important factors affecting the extraction and derivation of biogenic amines.Different brands and fermentation times of pixian chili-horsebean paste products were analyzed to evaluate the biogenic amine safety of commercially available products.Finally,the physical and chemical properties and dynamic changes of biogenic amines of natural fermented chili-horsbean paste during fermentation were studied.The main conclusions are as follows:1.The study of different acid extraction solvents such as HClO4,TCA,HCl,different extraction time like 1,2,3,4 times,different HClO4 concentration such as 0.3,0.4,0.5,0.6,0.7 mol/L were used to optimize pretreatment extreaction of biogenic amines in pixian chili-horsebean paste.Then use different derivatization time such as 10,25,40,55 and 70 min,different temperature like 10,25,40,60 and 80℃,then add different derivatizing agents dansyl chloride with volume 1,1.5,2,2.5,3 mL respectively to optimize pre-column derivatization.The results showed that the pretreatment method of sample was to use 0.4 mol/L HClO₄ extraction solution to extract the biogenic amines in sample twice.The optimal biogenic amine derivatization condition was to add 2.5 mL of 10 mg/mL dansyl chloride solution at 40℃for 40minutes,which can get a good derivatization effect.Under this condition,the biogenic amines in pixian chili-horsebean paste can be detected more accurately and efficiently.2.Evaluate the safety of 8 biogenic amines and quality indicators like total acid,pH,salt content and AN in 21 commercially different brands and fermentation time pixian chili-horsebean paste products.The results showed that the content of biogenic amines in 21 products varied from（86.85±1.99）～（611.83±7.16）mg/kg,all samples did not exceed the total recommended content 900 mg/kg of biogenic amines in foods,the content of putrescine,cadaverine,histamine and tyramine in paste were higher than other kinds of biogenic amines in products,some samples even exceeded the recommended values of international researches,indicating that the content of biogenic amines in some pastes products were not completely within the safe level of human consumption.In addition,the total amount of biogenic amines in red oil chili-horsebean paste 231.82 mg/kg was higher than that in traditional pixian chili-horsebean paste190.19 mg/kg.3.The pH of 21 kinds of pxian chili-horsebean paste was（4.29±0.01）～（5.02±0.01）,the salt content was between（11.9±0.01）～（24.2±0.29）%and AN varied from（0.56±0.01）～（0.88±0.006）g/100g,the content of AN meet the standard of pixian chili-horsebean paste.Total biogenic amines content showed a weak correlation between pH,but the content of histamine and tyramine in different pixian chili-horsebean paste samples showed significant correlation.4.The object of this study was to learning the changes of biogenic amines content and quality indexes of 0,5,10,15,20,30,40,50,70 and 90 fermented days of chili-horsebean paste fermentation.The results showed when increased fermentation time,the quality indicators like total acid,AN and salt content of chili-horsebean paste were gradually increased,while pH,moisture content,Aw,L*and a*values??were gradually decreased.After 90 days of fermentation,the color was dark-reddish-brown,and it was thick and fluffy,the aroma was intense.5.The microorganisms in chili-horsebean paste showed dynamic changes during the fermentation process,and the types of bacteria in salted chili were more abundant than fermented bean paste.The total number of colonies,bacillus and yeast decreased significantly（P<0.05）.Lactobacillus,mold and enterobacteria could not be detected through the culture medium after 50,30 and 5 days of fermentation.Tryptamine,β-phenylethylamine,putrescine,cadaverine,histamine,tyramine and spermidine showed a slow increase during fermented time.The total biogenic amines content was129.56±4.44 mg/kg after 90 days,which didn’t exceed recommended values or standards.6.A total of 59 volatile flavor compounds were detected in chili-horsebean paste after 90 days,including 20 esters,11 alcohols,5 aldehyde,8 acid,7 ketone,and 2phenol and other 6 compounds.