Effect Of High Pressure Steaming Combined With Roasting On The Flavor Of Buckwheat Flour And Its Noodle Quality

Buckwheat,as a potential functional food,has attracted widespread attention.Volatile flavor substances play an important role in the flavor quality of buckwheat and its products.High pressure steam(HPS)treatment is a processing method that can significantly improve the flavor of grains and optimize the flavor of buckwheat.However,HPS treatment can lead to excessively high moisture content in buckwheat samples,which poses safety issues for storage.Therefore,this project adopts a processing method of high-pressure steaming combined with baking to process buckwheat grains,analyze and study its effects on the flavor,physicochemical properties,and noodle taste quality of buckwheat flour,aiming to provide technical support and theoretical guidance for the development and high-value utilization of buckwheat nutrition and health products.The main research content is as follows:The high-pressure steam combined with roasting treatment will have a certain impact on the volatile flavor substances of buckwheat flour.Using solid-phase microextraction(SPME)technology and gas chromatography-mass spectrometry(GC-MS)to compare the effects of high-pressure steam treatment,HPS-high-temperature short-time roasting(HPS-HTSR)treatment,and HPS-low-temperature long-time roasting(HPS-LTLR)treatment on the formation of volatile flavor substances in buckwheat flour.The results show that there are 49 volatile components in buckwheat flour treated with high-pressure steam combined with baking treatment,of which aldehydes and terpenes contribute significantly to the flavor of buckwheat flour under the action of HPS treatment,while aldehydes,terpenes,and pyrazines contribute significantly to the flavor of buckwheat flour under the action of HPS-HTSR treatment,and aldehydes contribute significantly to the flavor of buckwheat flour under the action of HPS-LTLR treatment.Principal component analysis(PCA)was used to analyze the volatile components in different treatment processes,and the results show that the cumulative contribution rate of the three main components of volatile flavor substances in buckwheat after high-pressure steam and baking treatment reached 91.69%.The calculated sweet buckwheat flavor score after different treatments showed that the score of HPS treatment was greater than that of HPS-HTSR treatment,which was greater than that of HPS-LTLR treatment.For the flavor of buckwheat flour treated with HPS and HPS-LTLR,the flavor of HPS-LTLR was included in the buckwheat flour treated with HPS,while the similarity between the flavors of the two baking treatments was low,and the flavor differences were large.The components with higher contributions to the main flavor were identified by calculating the odor activity value(OAV).The results show that for HPS samples,the OAV value is greater than 10,and the substances that contribute significantly to the flavor are heptanal,salicylaldehyde,nonanal,decanal,1-octen-3-ol,and 2-methylnaphthalene;for HPS-HTSR samples,salicylaldehyde,nonanal,2,5-dimethylpyrazine,2,5-dimethyl-3-ethylpyrazine,and 2,6-diethyl-3-methylpyrazine contribute significantly to the flavor;for HPS-LTLR samples,the substances that contribute significantly to the flavor of buckwheat flour are salicylaldehyde and nonanal.HPS-HTSR/LTLR treatment has certain effects on the physicochemical properties of buckwheat flour,including basic components,gelatinization properties,thermal properties,crystal structure,microstructure,and starch digestion characteristics.The main conclusions are as follows: as the HPS-HTSR/LTLR treatment time increases,the degree of gelatinization increases,peak viscosity and trough viscosity,as well as final viscosity,all decrease,breakdown and setback values decrease.HPS treatment leads to a decrease in the swelling power and solubility of buckwheat starch,and thermal treatment destroys the hydrogen bonds and natural helical structure of starch molecules.After HPS-HTSR/LTLR treatment,the enthalpy of heat absorption of buckwheat flour significantly decreases,and the initial,peak,and final temperatures of gelatinization all significantly increase.After HPS-HTSR/LTLR treatment,the crystal structure of buckwheat flour starch changes from type A to type B,and the degree of crystallinity significantly decreases.Moreover,as the HPS treatment time is prolonged,the microstructure of buckwheat flour changes from visibly intact starch and protein structures to incomplete starch structures,with buckwheat starch and protein forming a mesh structure,and starch particles becoming indeterminate.The final digestion degree and RS content of HPS-HTSR/LTLR-treated buckwheat flour are higher than those of natural buckwheat flour.HPS-HTSR/LTLR treatment affects the sensory quality of buckwheat noodles.Addition of HPS-HTSR/LTLR-treated buckwheat flour increases the water absorption and decreases the breakage rate and cooking loss of buckwheat noodles,while decreasing hardness and increasing stickiness and chewiness to varying degrees.The content of flavor compounds also increases to different extents.Buckwheat noodles from the HPS-HTSR group have a sweet orange aroma with a hint of grassy notes,as well as increased fruity and camphoraceous notes from terpenes,rose and sweet orange aromas from alcohols,and a nutty aroma from pyrazine compounds.Buckwheat noodles from the HPS-LTLR group have a rich content of terpenes,with increased fruity aroma,as well as increased rose and sweet orange aromas from alcohols.Overall,the addition of HPS-HTSR/LTLR-treated buckwheat flour improves the sensory quality of natural buckwheat noodles to some extent,increasing elasticity and decreasing hardness and cooking loss,while enhancing flavor.Among them,the noodles from the HPSHTSR group are more popular and have a higher overall sensory score.