Preparation And Photostability Study Of Chili Red Oil And Its Application In Dry-fermented Sausage

The carotenoids and capsaicinoids in chili pepper are fat-soluble ingredients that give them red color and spicy flavor.Oil can extract and“wrap”them,reducing their exposure to oxygen,and delaying oxidative degradation.Therefore,the preparation of pepper into chili red oil is an effective way to protect the color and flavor substances of pepper.In addition,under different preparation conditions,these two substances and edible oil produce the unique color and flavor of chili red oil.However,once these two components are extracted,they are prone to oxidative degradation during processing and storage.Therefore,it is necessary to find suitable antioxidants that delay the degradation of the active ingredients in chili red oil.The previous study of our research group found that the color quality,pigment content,and antioxidant capacity of Erjingtiao pepper were better,and the spiciness was moderate.Therefore,in this study,Erjingtiao dried chili with better quality in different origins was selected to determine the better extraction conditions and ultrasonic-assisted conditions for preparing chili red oil,and the effects of antioxidants on the photostability of active ingredients in chili red oil were compared.Finally,chili red oil was added to air-dried sausages in order to improve the color and sensory quality.The specific research results are as follows:1.The quality parameters of the peel and seeds of Erjingtiao dried chili from four different origins,namely,Zizhong,Guizhou,Chengdu and Nanchong,were compared.The results showed that Nanchong Erjingtiao dried pepper had the highest percentage of peel content(P<0.05),lower moisture,highest ash and protein content(P<0.05),and moderate nutrient content such as vitamin C(Vc)and total sugar;Nanchong dried chili peels had higher redness(a*),yellowness(b*),color vale,and content of carotenoids,and lower brightness(L*)(P<0.05);Its capsaicin content was significantly lower than that of Zizhong and Chengdu dried chili peppers(P<0.05).Nanchong pepper seeds had lower water activity and capsaicin content,and the highest protein and ash content(P<0.05).Therefore,Nanchong Erjingtiao dried chili pepper is suitable for processing into chili red oil with medium spiciness and good color quality.2.Chili red oil was prepared with the high temperature and ultrasound-assisted extraction at the optimized process conditions,and then the quality of the optimized chili red oil was compared with that of four commercial chili red oils The results of single-factor test showed that the color value of chili red oil was the highest(P<0.05)when the chili powder was 80 mesh,the oil-to-paprika powder ratio was 6:1,the time was 10 min and the temperature was 120°C;the response surface optimization results showed that the color value was the highest(P<0.05)when the oil-to-paprika powder ratio is 4:1,the temperature is 120°C and the time is 12 min,which was 2.62;on this basis,the combined ultrasonic-assisted extraction was subsequently performed,the color value reached 3.58 after at a temperature of 40°C and a time of 1 h,which was about 1.33 times of that before ultrasonication.The comparison results showed that the color index of the optimized chili red oil was better than that of the four commercial chili red oils:its L*value was the lowest,a*value was the highest,and the b*value was in the middle level;the color value,capsanthin andβ-carotene content were significantly higher than those of the four commercial chili red oils(P<0.05),and zeaxanthin content was in the middle level,while the capsaicin content was lower.Therefore,the color and active ingredients of the chili red oil prepared by heating combined with ultrasonic-assisted in this experiment were higher,while the capsaicin content was lower.3.The effects of adding 0.008%rutin before(R1)and after(R2)preparation,and 0.008%vitamin E(V_E1)and 0.01%V_E(V_E2)after the preparation on the color and active ingredients of chili red oil were compared under ultraviolet illumination.The results showed that the L*value gradually increased,a*value increased and then gradually decreased,the color value and active ingredient content gradually decreased,while b*value of R2 and V_E2 groups gradually increased,while the other three groups increased and then decreased(P<0.05).The content of zeaxanthin and capsanthin after 48h,a*values and color value after 72 h in R2 group were significantly higher than those in control group(Con),R1 and VE1 groups(P<0.05);The R2group had the lowest L*value,but highest a*value,color value,capsanthin,zeaxanthin,capsaicin and rutin content at 120 h.In a comprehensive comparison,the addition of 0.008%rutin after preparation of chili red oil(R2)could effectively protect the active ingredients in chili red oil.4.The effects of 5%(LO)and 8%(HO)chili red oil combined with Flos Sophorae Immaturus on the physicochemical indexes of air-dried sausage during ripening and storage were studied.The results showed that the color index,carotenoids,capsaicin,rutin and quercetin contents of all groups of air-dried sausages gradually decreased with time,while the acid value and thiobarbituric acid value(TBARS value)gradually increased.Compared with the control group(Con)and the addition of 150 mg/kg nitrite(Nit),LO and HO significantly reduced the TBARS(P<0.05),and significantly increased color and flavor of air-dried sausage(P<0.05).Compared with Con and Nit groups,LO and HO groups had higher water content,p H value,DPPH clearance rate,acid value and lower nitrite residue(P<0.05),and the addition of chili red oil reduced the L*value of the air-dried sausage,due to the abundant carotenoids in the chili red oil and the chlorophyll in the Flos Sophorae Immaturus,and the a*value and b*value were higher.LO and HO groups reduced the hardness and chewiness of air-dried sausage,improved a*,b*,the flavor,taste and texture score,enriched the dominant flavor substances,and reduced the flavor substances produced by microbial metabolism(e.g.,hexanal).The contents ofβ-carotene,rutin and quercetin in LO group were significantly higher than those in HO group(P<0.05),and the water content and hardness were significantly lower than those in HO group(P<0.05).Therefore,the combination of Flos Sophorae Immaturus and 5%chili red oil(LO)improved the color quality,texture characteristics,sensory scores,antioxidant capacity and active ingredients content in air-dried sausage.In summary,the overall quality of Nanchong Erjingtiao dried pepper was superior;the color value was further improved by preparing chili red oil at high temperature under better conditions,and then combined with ultrasound-assisted extraction(40°C,1 h),and its color quality was better than that of the four commercial chili red oils;the addition of 0.008%rutin after the preparation of chili red oil could enhance the photostability of the active ingredients in chili red oil and improve the color quality;the combination of 5%chili red oil and Flos Sophorae Immaturus could improve the color,antioxidant capacity,sensory and texture quality of air-dried sausage.