Study On Extraction Technology And Application Of Crude Protein From Flue-cured Tobacco

With China’s accession to the international anti-smoking organization,the total cigarette production has been reduced year by year,resulting in the accumulation of a large number of surplus flue-cured tobacco are abandoned.Therefore,how to reasonably store flue-cured tobacco has become an urgent problem to be solved in the tobacco industry.Tobacco protein contains all essential amino acids and has high utilization value.It can be used in feed,food,medicine,bioactive peptides and other fields after processing.Therefore,tobacco is of great research significance.This paper aims at the problems of tobacco protein extraction,such as time-consuming work,tedious process,low protein content,narrow application,not suitable for industrial extraction and production and so on.And the extraction technology,amino acid composition and functional properties,small-scale extraction and application in dog feed of flue-cured tobacco crude protein are studied systematically.The main results are as follows:1.Through the study of flue-cured tobacco crude protein extraction process,the process route is deter mined as follows: crush tobacco→homogenate→enzymatic extract→filtrate→alkaline heat sink→centrifuge→wash→natural precipitate→spray dry.The main process parameters are as follows.First of all,the flue-cured tobacco is crushed to 1 mm,the ratio of grinding extraction material to liquid is set as 1: 10,the extraction solution is added p H8.0 phosphate buffer,and the extraction temperature was set at 30 ℃.Then,after 7 min of colloid grinding,1% 10 w u/g cellulase is added for enzymatic extraction(enzymatic hydrolysis temperature 50 ℃,enzymatic hydrolysis time 2 h,enzymatic hydrolysis suitable for p H 6.0).The enzymatic hydrolyzed pulp is filtered with a double-layer 200 mesh filter cloth.Then,the filtrate is adjusted to p H9.0,with 1 mol/L Na OH,and set heat sink and time of 60 ℃ and 30 min separately.Tthe protein precipitate is centrifuged at 3000 r/min for 10 min.After abandoning the supernatant,add distilled water to wash with the volume ratio at 1:1.Finally,the supernatant is filtered and spray drying is carried out after natural precipitation for 1 hour.Under this process,the extraction rate of flue-cured tobacco crude protein is 42.58%,and the highest protein content is 31.51%.2.Through the analysis of amino acid composition and functional characteristics of crude protein of flue-cured tobacco,the main results are as follows:(1)The crude protein of flue-cured tobacco contains all the amino acids necessary for human body,and the ratio of E/N and E/T is higher than the standard value given by FAO/WHO.According to the comprehensive amino acid score and chemical score,the score of flue-cured tobacco crude protein is higher as a whole.The first limiting amino acid is sulfur-containing amino acid(methionine and cystine),and the second limiting amino acid is lysine.(2)Salt ion concentration has a certain effect on the solubility,water retention,oil absorption,foaming,foam stability,emulsification and emulsifying stability of crude protein of flue-cured tobacco.When other conditions are constant,the solubility,water retention,foaming and foam stability of crude protein of flue-cured tobacco can reach the maximum by adding Na Cl solution with the concentration of 1.0 mol/L.Under the condition of external p H6.0-8.0,its functional properties such as solubility,foaming,emulsifying property and emulsifying stability are relatively optimal.The solubility,water holding capacity,emulsifying property and emulsifying stability of crude protein of flue-cured tobacco are the best at 50℃,and the temperature has a significant effect on the oil absorption of the protein.In the range of 20-70 ℃,the oil absorption increases with the increase of temperature,while the foaming property and foam stability show a reverse development trend in this range.3.Through the small-scale experiment of 100 times magnification of the crude protein extraction process of flue-cured tobacco in the laboratory research stage,the results show that the extraction rate of crude protein of flue-cured tobacco is 35.74%,and the loss rate is 6.84%.Under this experimental condition,the production cost of extracting a can(500 g)of tobacco protein powder is about 70.53 yuan,which is lower than that of plant protein powder sold in the market.The production process and equipment parameters can be applied to industrial production.4.The crude protein of flue-cured tobacco is used as additive in the development of dog food.Referring to the AAFCO nutrition standard,the formula of dog food is designed according to the different growth periods of dogs.The puppy food formula is used as the template for laboratory processing.The finished dog food had good particle agglutination,smooth surface,consistent color,size and strong aroma.The simple feeding experiment shows that the puppy had high acceptance to the prepared dog food.The formula of puppy food is as follows: flue-cured tobacco crude protein13.5%,rice 20%,corn flour 30%,wheat bran 10%,fish meal 15%,milk powder 5%,calcium dihydrogen phosphate 1%,salt 0.5%,microvita min-element premix 5%.The best puffing conditions of puppy food are as follows: puffing temperature 95℃,screw speed 50 r/min,feeding speed 0.3 kg/min.To sum up,the batch extraction process and related equipment parameters of crude protein from flue-cured tobacco are determined.And the crude protein of flue-cured tobacco with protein content more than 30% is obtained.The preliminary animal feeding experiment shows that it can be used as a feed additive protein in the development of dog food,which provides technical support and theoretical reference for the comprehensive development and utilization of flue-cured tobacco resources.