Study On Preparation And Characteristics Of Chicken Bone Protein Powder By Ultrasonic Assisted Enzymatic Method

The chicken skeleton is the main by-product of the segmentation of chicken production,in which the bone accounts for most of the weight,and contains remaining muscles,connective tissue and fat,etc.,and is considered to be a very valuable source of protein.Chicken skeleton is low in price and abundant in resources,but at the moment,most of them are directly discarded,except that some of them are processed into low value bone meal feed.Bone resources are not only wasted but also pollute the environment.Therefore,the comprehensive utilization and deep processing of chicken bone resources will be of great practical significance.The purpose of this study is to use ultrasonic technology to assist the traditional enzymatic extraction of protein from chicken bone,and to study the effect of ultrasonic treatment on the structure and functional properties of chicken bone protein.The chicken bone protein powder is prepared by spray drying technology and its nutritional value is evaluated.It is expected to provide a theoretical basis for the deep processing and product development of chicken bone.The contents and conclusions of this paper are as follows:1.Study on enzymatic extraction of chicken bone protein7 kinds of protease were used to extract chicken bone protein under optimum conditions,and protein extraction rate and degree of hydrolysis were used as indicators.The papain was selected for enzymatic extraction of chicken bone protein.On this basis,the single factor experiment was carried out by ordinary enzyme extraction,and the optimum process parameters were optimized by the response surface method: The concentration of the substrate was 3.1 %,the amount of enzyme was 4019 U/g,the temperature was 42 ?,and the pH value was 6.9.The extraction rate of protein was 50.47 %.2.Study on the extraction of chicken bone protein by ultrasonic pretreatment assisted enzyme methodThe chicken bone was pretreated with ultrasonic technique and was extracted by enzyme method.On the basis of single factor test,optimum process parameters of ultrasonic pretreatment were optimized: The ultrasonic conditions were 400 W,120 min and 45 ?.Under these conditions,the extraction rate of chicken bone protein was 56.49 %.The extraction rate of chicken bone protein was significantly improved by ultrasonic pretreatment assisted enzyme method.3.Study on the effect of ultrasonic pretreatment on the structure and functional properties of chicken bone proteinThe effects of ultrasonic pretreatment on the structure and functional properties of chicken bone protein were studied.The results showed that ultrasound not only changed the secondary structure of chicken bone protein,but also improved the surface hydrophobicity of the chicken bone.Ultrasound pretreatment did not change the shape and maximum emission wavelength of chicken bone protein,but decreased its fluorescence intensity,indicating that the spatial conformation of chicken bone protein was changed.Ultrasonic pretreatment had no significant effect on the molecular weight of chicken bone protein,but obviously improved its solubility,emulsification,foaming and oil holding capacity.4.Study on the preparation of chicken bone protein powder by spray dryingThe chicken bone protein extract was spray dried to prepare chicken bone protein powder.The effects of spray drying conditions(feed concentration,inlet air temperature,and air intake)on the quality of chicken bone protein powder were investigated using the collection rate,moisture,wettability,dispersion time,bulk density,and angle of repose as indicators.The results showed that the technological parameters of spray drying for preparation of chicken bone protein powder should be controlled in the following aspects: the feed concentration was 20 %,the inlet air temperature was 180 ?,and the air intake was 80 %.The chicken bone protein powder prepared under this condition had high powder collecting rate,low moisture content and good fluidity.5.Evaluation of nutritional value of chicken bone protein powderThe basic nutritional components and amino acid composition of chicken bone protein powder were measured,and the nutritional value of chicken bone protein powder was evaluated by chemical evaluation.The results showed that the product had high protein content,low moisture content and fat content and can be added as a protein supplement to foods.The content of glutamic acid in chicken bone protein was the highest,accounting for 17.37 % of the total amino acid content.Compared with chicken bone meal,the content of fresh amino acids in protein powder increased by 36.09 %.The nutritional value of chicken bone protein was lower than whey protein concentrate,slightly higher than soy protein isolate.Methionine and cysteine were the limiting amino acids of chicken bone protein.The chicken bone protein and whey protein concentrate can be matched with each other to jointly improve the nutritional value of both.