Functional Characteristics Of Germinated And Cooked Highland Barley Powder And Its Application Research In Baking Food

Highland barley is a kind of high nutritional value of local resources of cereal,rich in γ-aminobutyric acid(GABA),β-glucan and other health function components.However,due to the high fiber content and not easy to grind,the use of flour products and baking products often brings the problems of rough taste and loose organization,poor processing performance and limited amount of addition,which seriously restricts the large-scale development of highland barley processing industry.Aiming at the key common problems in the deep processing and application of highland barley,the raw materials and products of highland barley were studied.By analyzing the influence of germination and different cooking methods on the nutritional characteristics,structure function and powder properties of highland barley grains,the cooking method for highland barley raw materials with high retention of characteristic nutrients was explored.Taking baked cakes as the entry point for the application of cooked flour,Cantonese almond cake was selected as the representative of low-moisture products,and chiffon cake as the representative of high-moisture products.The flour properties and product quality in the application of highland barley powder were systematically studied,and the baking method was optimized to improve the production efficiency.The purpose is to break through the bottleneck problem of the application of highland barley raw materials,enrich the varieties of highland barley processing products,and provide reference for the realization of energy saving and consumption reduction in the processing process.The main research contents and results include:(1)Aiming at the problem that the traditional high temperature frying has a great damage to the functional components of highland barley,the effects of germination and different cooking methods on the characteristic functional components of highland barley were discussed by using high performance liquid chromatography(HPLC),mixed enzymatic detection and other method.The results indicate that: During the germination,γ-aminobutyric acid content increased nearly linearly,β-glucan content gradually decreased,resistant starch content increased first and then decreased.Under the premises of taking into account the nutritional composition,flour yield and germination cycle,the time point of subsequent cooking was selected to the 24 h after germination.And the grains in this state were fried,heat-baked,and microwave cooked.In the early stage of all cooking processes,the resistant starch content of grains increased to different degrees.But as the treatment temperature(100 ?C→140 ?C)or the power density(1.5 W/g→2.5 W/g)increased,the loss rate of γ-aminobutyric acid increased.Whereas the high pressure steaming and cooking was helpful for the enrichment of β-glucan in germinated grains.(2)The effects of different cooking methods on the character structure and powder properties of germinated highland barley were studied by means of the X-ray diffractometer,viscosity analyzer,headspace-solid phase microextraction-gas chromatography-mass spectrometry(HS-SPME-GC-MS)and other technology and the method of principal component analysis.The results indicate that: In the case of the cooked highland barley powders made under the same crushing condition,their degree of swelling and content of resistant starch increased,while their particle size,water absorption index,oil retention and solubility decreased,and their gelatinization viscosity and crystallinity also decreased to different degrees compared with the raw barley powder.GABA enrichment rate was 9.71～34.90% in the barley cooked powder prepared by the combination of germination and cooking.Among them,the highest retention rate(73.96%)and the lowest relative crystallinity(3.20%)were obtained under the frying condition(120 ?C,39.7 min).The powder with highest relative crystallinity(20.33%),the enrichment rate(34.90%)and the alcohol aroma content(5.03%)were produced under 100 ?C hot air for 83.5 min.Compared with other cooking methods,microwave-cooked barley grains had the most obvious pores,and their powder after milling had the smoothest peak shape of the viscosity and relatively low β-glucan content,while their vale or the content of median particle diameter,a*,b*,peak time,resistant starch,iodine blue was higher.(3)Application in high-moisture baking products: In order to solve the problem that highland barley chiffon cake with high content(50g / 100g)is difficult to expand and has rough structure under the traditional hot air baking condition,the influences of flour composition,batter characteristics and baking process on the quality of highland barley cake were discussed.The results indicate that: Replacing 50% wheat flour with highland barley flour will change the characteristics of the batter and the formation of crumb structure in the baking process.Powder used in the proportion of amylopectin/total starch and the flow behavior index of corresponding batter show very strong positive correlation(r = 0.892).The cell-to-total area ratio of cakes was positively correlated with the enthalpy of powder and the bubble growth rate of batter(r = 0.678,0.769),while negatively correlated with the consistency coefficient and flow behavior index of batter(r = 0.941 and 0.628).Microwave(800 W)pretreatment for 20 s could make the highland barley batter rapidly expand to the maximum volume point,followed by hot air baking for 35 min to obtain the cooked cake,with fine structure,high stomata density and uniform distribution.It is not only conducive to improving the specific volume,rough feeling and internal viscosity of the cake baked with single hot air process(170 ?C,50 min),but also can optimize the appearance,color,texture,mouthfeel,stomata pore distribution uniformity and the cavity wall uniformity of the cake cooked by pure microwave(800 W,95 s).(4)Application in low-moisture baking products: In view of the problems of poor formability,shape defect and rough taste of cooked pastries with high highland barley powder content(≥ 40%),the influence of screening fineness of highland barley flour on Cantonese almond cake powders(mung bean flour,< 125 μm)and its products was mainly explored.The results indicate that: The finer the sieving highland barley powder is,the lower the content of protein,dietary fiber and ash is,the higher the degree of starch and expansion is,the worse the thermal stability is,the more the microstructure tends to typical starch granules,the smaller the water absorption index(40～80% compound ratio)is,the better the product formability(0～40% compound ratio)is.With the decrease of the proportion of highland barley powder,the compressibility and oil holding capacity of the system of <125 μm highland barley powder decreased.And when the highland barley powder with 180～280 μm,125～180 μm,and < 125 μm were combined with the mung bean flour at the proportions of < 20%,≤ 20%,and ≤ 80%,respectively,the texture and taste of products made from them was close to that of the traditional Cantonese almond cake,and their content of dietary fiber,β-glucan and GABA were significantly increased.