| Betel nut is a palm plant that is not only widely used as a medicine in the medical filed,but has also become the fourth most psychologically dependent food in the world after alcohol,caffeine and cigarettes.However,due to some technical problems in betel nut manufacturing process,the fiber of commercial betel nut has become harder.Long-term chewing of betel nut will not only cause damage to teeth,but also lead to oral cancer,and endanger human health.With the rapid development of betel nut industry,the public is also paying more attention to the health problems caused by chewing hard betel nut.Therefore,the softening of betel nut has become an urgent problem for betel nut industry.In this study,the hardness evaluation system of betel nut was established firstly.After then,the new hardness evaluation system was used to evaluate 4 different betel nut softening methods.Based on above researches,the new combination and ratio of betel nut enzymatic hydrolysis and softening were determined.The enzymatic hydrolysis and softening conditions of betel nut were optimized.The main results are as follows:1.A series of physical properties of commercial betel nut,including hardness,elasticity,viscosity,mastication and water content,were measured by using of texture analyzer and Shore hardness tester.The results showed that the physical properties of the commercial samples were significantly different,with hardness range of 269.7-395.8 N,elasticity range of 3.33-4.23 mm,adhesiveness range of 114.2-198.2 N,mastication range of 364.9-487.9 m J,Shore hardness range of 18.45-26.25 HD,and water content range of 21.78-24.83%.According to the sensory evaluation table,the hardness of commercial betel nut samples was evaluated.The correlation between betel nut hardness,water content and sensory evaluation scores was studied.The results showed that the water content had a significant effect on the betel nut softening,which suggested that the water content should be controlled at the same magnitude in betel nut softening experiment.At the same time,the softener effect of betel nut was verified by combining texture instrument,Shaw hardness tester and sensory evaluation,so as to select the best softener.2.The betel nut was softened by four different treatment of freezing,manual tapping,microwave and enzymatic treatment.The effect of each method on the results of the Texture Profile Analysis(TPA)(including hardness,elasticity,adhesiveness and chewing),Shaw’s hardness,sensory evaluation score and content of arecoline was analyzed.It was found that various softening methods all had significant influence on the hardness and taste of betel nuts,with a reduction of hardness ranging from 8%-35%..However,the various methods also had disadvantages.Although freezing treatment can maintain the morphology and material components of betel nut,but the softening effect was not significant,the relative softening rate of the betel nut was only 9%(P<0.05).The softening effects of manual tapping,microwave and enzymatic treatment were 25.6%,34.8% and 30.5% respectively.The manual tapping can maintain the content of arecoline to the maximum,where the loss of arecoline was only 0.28%.However,the manual tapping required semi-processing,which might need to change the processing sequence in actual factory production.Microwaves have a significant influence on arecoline,and the loss of arecoline was as high as 22.55%.In addition,the microwave caused a significant deformation of betel nut.The current biological enzymatic treatment can maintain the morphology of the sample.Besides,the treatment process was environment-friendly and pollution-free.The enzymatic treatment had a better effect,but there still had the problem of high rate of slag loss,which affected the taste of betel nut.3.To improve the current enzymatic softening process of betel nut,the problems of poor chewiness and high rate of scum dropping were improved by replacing pectinase with lignin degrading enzyme(laccase)to form a new combination of laccase,cellulase and hemicellulase for the mixed enzymatic softening of betel nut.It was firstly found through single-factor experimental that the best combination were 30 U / g of laccase,20 U / g of cellulase,and 40 U / g.Reusing the response surface analysis method for three-factor threelevel enzymatic matching optimization experiment,with the relative softening ratio of the betel nut shell in the softening betel nut as the response value,and the secondary multimathematical model was established using statistical methods.Optimization of response surface data and model equation was determined to determine the best matching of complex enzymes.The optimum enzyme ratio of the enzymatic dehydrated betel shell was obtained:the paint was 32.6 U / g,the cellulose amount was 20.8 U / g,and the amount of pectin was38 U / g.4.Three factors affecting the enzymatic hydrolysis,which were temperature,p H and time of the enzymatic hydrogenation.Firstly,through a single factor experiment,and the enzymatic hydrolysis temperature was 50 ℃,p H was 5.0,and the enzymatic solution was5.0 h.Reusing the response surface analysis method,three factors interacting,with the relative softening ratio of the betel nut as a response value evaluation index,two multimathematical models were established.Optimization of response surface data and model equation indicated that the optimal conditions of enzymatic hydrolysis betel nut were: the enzymatic hydrolysis temperature was 46 ℃,p H was 5.1,and the enzymatic solution was 5h.5.The use of new composite enzyme-free softening betel nuts was compared with the traditional enzymatic dehydrating betel nut dominated by cellulase,hemicrase and pectinase.The relative softening rate of the betel shell was 10 percentage points,and the slag sexy The official score was 16 points,indicating that the betel nut after the new composite enzymatic solution was smaller than softening than the traditional enzymatic hydrolysis,not only soften,but the taste was better as well,and the slag rate was also significantly reduced. |
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