Comparative Studydiverse Varieties Hazelnut Powder And Hazelnut Protein Of Physicochemical Properties

Hazelnut，as one of the four major types of nuts in the world, is a kind of perfect foodprocessing materials with rich nutrition and good flavour. Four hazelnut varieties Corylusavellana ‘Barcelona’, Corylus heterophylla Fisch ‘Pingzhen1#’, two C. heterophylla Fisch.×C. avellana L.‘Liao zhen3#’ and ‘Dawei’ as test materials were used to study the followingaspects:(1) optimizedthe technology for peeling Hazelnut kernel by lye.(2) Contrasted thedifference of material composition and physicochemical properties of hazelnut powder whichobtained through degreasing, vacuum freeze drying, crushing and sieving of hazelnut kernelamong different varieties of hazelnut with peel and without peel, analyzed the relationshipbetween material composition and physicochemical properties.(3) Studied the main basicdphysicochemical properties of hazelnut protein powder which obtained using the method ofalkali-solution and acid-isolation. The main results were as follows:1Optimization of the technology for peeling hazelnut kernel by lyeThe difficulty of peeling hazelnut kernel was closely related to varieties.‘Pingzhen1#’was the easiest to peeling among these four varieties and then was Corylus avellana‘Barcelona’. C. heterophylla Fisch.×C. avellana L.‘Liao zhen3#’ and ‘Dawei’ were themost difficult to peel of them. Peeling optimization of process conditions for each varietyrespectively were:‘Pingzhen1#’45℃in0.6%NaOH solution for2.5min,‘Barcelona’ in50℃in1.0%NaOH solution for2.5min,‘Liao zhen3#’50℃in1.0%NaOH solution for4.0min,‘Dawei’ at50℃in1.2%NaOH solution for3.5min, the peeling rate were93%,90%,87%and93%respectively, and L values of these four kinds of kernel were all above60.In practical production, NaOH concentration should be controlled as the priority whileprocessing time and temperature should be controlled selectively according to the varietycharacteristics.2Material composition and physicochemical properties of hazelnut powderProtein was the highest content composition in hazelnut kernel, then the content of thosecompositions lowered successively following by soluble sugar, cellulose, starch and ash. Thetotle protein contents of ‘Pingzhen1#’ and‘Liao zhen3#’ were obviously higher than that ofother two varieties, but the soluble protein content of ‘Barcelona’ was significantly higherthan other three varieties. The content of each basic composition among different varietyhazelnut powder were different to some extent. Eight kinds of Essential Amino Acid were allin the four varieties hazelnut powder, but the total content of hydrolyzed amino acid wasranged from375.5g·kg-1Dw to495.2g·kg-1Dw with significant difference among differentvarieties of hazelnut powder. There was no significant effect on the contents of protein,soluble protein, starch and soluble sugar of hazelnut powder by peeling treatment, but crudefiber content obviously decreased and ash content remarkably increased after peelingtreatment.There were different variation trends between solubility and swelling power of hazelnutpowder with changing of temperature. With temperature rising, the variation tendency ofsolubility was increasing firstly and then was decreasing, the changing tendency of swellingpower was increasing at the first and then stabilized the higher level to the end. The solubilityof hazelnut powder were significant difference in different temperature to the same variety and different varieties at the same temperature as well. The peak of solubility were at70℃toall the four varieties hazelnut powder. The solubility of hazelnut powder were significantlypositive correlation with soluble protein, soluble sugar and starch content and remarkablynegative correlation with ash content. The swelling power were significantly positivecorrelation with starch content and remarkably negative correlation with total protein content.Peeling treatment was no significant influence to the solubility and swelling power.At protein isoelectric point (pH4.5) of hazelnut powder emulsifying ability and foamingability were worst, alkaline conditions of emulsifying ability and foaming ability were betterthan acid and neutral conditions; at protein isoelectric point and alkali conditions of emulsionstability was good, and the foam stability at protein isoelectric point and the acidic conditionswas good. Soluble protein content was significantly positive correlation with the emulsifyingability of hazelnut powder, and significantly negative correlation of emulsion stability andfoam stability; Foaming ability of hazelnut powder were significantly positive correlationwith protein content. Emulsification and foamability of hazelnut powder were closely relatedto varieties, peeling treatment was improve them; PH was significant influence of hazelnutpowder emulsifying ability, stability and foaming ability, emulsification and foamability werethe same change trend with pH change basically; Soluble protein was beneficial to improve ofthe emulsifying ability, and was not conducive to emulsion stability and foam stability,protein content was closely related to the foaming ability.Hardness and elasticity of hazelnut powder gel were significantly influence withhazelnut powder mass concentration and glucose acid lactone (GDL) content. Hazelnutpowder mass concentration was higher, hardness and elasticity of the gel were greater. Whenhazelnut powder mass concentration certainly, increased GDL adding quantity was make gelhardness increases, and gel elasticity was worse instead. Gel hardness of the hazelnut proteinwas significant effect of varieties, and elastic had no difference.3The physical and chemical properties of hazelnut protein powderWater holding capacity of hazelnut protein powder was significantly change when pHvalue was not greater than8.5, and was significantly different among varieties. At proteinisoelectric point of water holding capacity was the worst, and partial acid and alkaliconditions were much better. Oil absorption of the protein powder was first increased andthen decreased with increasing temperature, at40℃was the peak, oil absorption of hazelnutprotein powder was negative whether the temperature was higher or lower. Oil absorption wassignificant effect of varieties, it was closely related to the hazelnut varieties.Emulsification and foamability of hazelnut protein powder were significant effect ofvarieties, emulsifying capacity and stability of ‘Barcelona’ were better, and‘Dawei’ was worst;foaming ability and stability of ‘Pingzhen1#’ protein powder were the best, and ‘Dawei’ wasthe worst. Gel hardness of hazelnut protein powder:‘Pingzhen1#’>‘Liao zhen3#’>‘Dawei’>‘Barcelona’, elastic was ‘Barcelona’ the best,‘Pingzhen1#’ and ‘Liao zhen3#’ were poor; itwas good hardness of gel, elasticity was not, and vice versa.