Effects Of Bamboo Leaves Extract Concentration Curing Combined With Bamboo Poles Smoking On Flavor And Antioxidant Properties Of Bacon

Bacon is a famous traditional cured meat product in China.As western-style meat products seriously impact the market of traditional Chinese flavored meat products,bacon products are in urgent need of improvement and innovation to increase their competitiveness.Bamboo is widely planted in southern China,but its utilization rate is not high,which is prone to waste of resources and environmental pollution.Bamboo leaves are not only rich in natural antioxidant flavonoids,but also the volatile oil in bamboo leaves has the characteristic flavor of typical green leaves,similar to the aroma of melons and fruits,and is a good raw material for the preparation of pickling liquid.Bamboo poles have high cellulose content,high thermal effect,cheap and easy to obtain,and are excellent smoking materials.In this study,the active ingredients in bamboo leaves were extracted with a certain concentration of ethanol solution,concentrated under reduced pressure,and used as a pickling solution to delay the oxidation of bacon and impart a unique fragrance of bamboo leaves at the same time.Combined with different proportions of bamboo poles for smoking,on the one hand,it can improve the quality of traditional cured meat,on the other hand,it can make full use of bamboo resources.The specific research results are as follows:In order to investigate the effects of extraction time,temperature,ethanol concentration and solid-liquid ratio on the extraction rate of flavonoids from Bamboo leaves,the optimal extraction process was optimized by single factor and response surface experiment with fresh bamboo leaves as raw materials and flavonoid extraction rate as index.The results showed that the four factors had significant effects on the extraction rate of flavonoids(P <0.01).The optimal extraction conditions were as follows: extraction temperature was 79.8 ?,solid-liquid ratio was 1?50.97(g/m L),ethanol concentration was 79.65% and extraction time was 3.74 h.The maximum extraction rate of total flavonoids was 5.45%.The scavenging rates of DPPH,ABTS,superoxide anion and hydroxyl radical of bamboo extract increased gradually with the increase of mass concentration,and the scavenging ability of ABTS and superoxide anion was close to that of Vc.The experiment results showed that bamboo extract had good antioxidant ability.In order to explore the effect of the moso bamboo leaves extract concentrate combined with bamboo poles smoking on the sensory quality and volatile compounds of the bacon,the moso bamboo extract concentrate were used to pickle and then the bamboo poles powder and cypress sawdust were used in a mass ratio of 1?0,2?1,1?1,0?1 for smoking,the physical and chemical indicators,such as texture,sensory and volatile flavor substances of four groups were determined.The results showed that with the increase of the proportion of bamboo poles powder in the smoked material under the same conditions,the L* and a* values increased significantly,the moisture content decreased,and the nitrite content increased but still fell below the standard range.The hardness,resilience,cohesion and chewiness were significantly higher than the pure cypress smoked group and the two-mix smoked group,the comprehensive sensory score was the highest as well.In addition,electronic nose linear discrimination analysis(LDA)combined with principal component analysis(PCA)could effectively distinguish the four treatments.Gas chromatography-mass spectrometry(GC-MS)analysis results showed that the increase in the smoking ratio of bamboo poles will increase the relative content of aldehydes,ketones,hydrocarbons and furan compounds,while the relative content of phenols and alcohols will decrease.It showed that the bamboo leaves extract concentrate combined with pure bamboo smoke could give the bacon better flavor and sensory quality.Bamboo leaves extract concentrate(BEC)was used as curing liquid,while different ratios of bamboo poles and cypress(1?0,2?1,1?1,0?1)were applied as smoking materials in bacon to investigate the oxidation and flavor effects during storage.The results indicated that the oxidation degree and residual nitrite content of the four groups remained lower during the whole storage.As for flavor compounds before and after storage,the differences between the bamboo poles and cypress 1?0 group were mainly reflected in aldehydes,esters and alcohols,and the difference between the bamboo poles and cypress 2?1 group and 1?1 group were mainly reflected in ketones,alcohols and acids.While the differences between the bamboo poles and cypress 0?1 group were mainly reflected in hydrocarbons and phenolics,accompanied by heavier resin and smoky odor as well as onefold main flavor compounds after storage.According to the oxidation degree and the overall changes in flavor compounds,full bamboo poles smoking group was considered as the best among the four groups.