Study On The Process And Characteristics Of Stone-milled Dried Whole Wheat Noodles

Compared to refined flours derived solely from the endosperm,whole wheat flour(WWF)is rich in bioactive components and has a variety of health-promoting effects.Due to the retention of bran and germ in WWF,dried whole wheat noodles suffer from poor color,rough mouthfeel,and a high cooking loss rate.In this paper,the basic composition,color,farinography properties,pasting properties,thermal properties,functional properties,Fourier infrared spectra,and microscopic morphology of starch granules of five particle sizes of stone-milled WWF were investigated to analyze the quality differences among particle sizes of WWF.WWF particle size,salt addition,curing time,and water addition were selected as single factors,the color of the dough sheet and the cooking properties,texture properties,sensory score,and in vitro antioxidant activity of dried noodles were investigated,and then the response surface design combined with the entropy weight method was used to optimize the process of stone-milled dried whole wheat noodles(SDWWNs).Dried wheat noodles(DWNs)and commercially dried whole wheat noodles(CDWWNs)were used as controls to study the quality advantages of SDWWNs by analyzing the cooking quality,textural properties,microstructure,Fourier infrared spectra,antioxidant activity prior to and after the in vitro simulated digestion,digestive properties,and glycemic index,which may provide theoretical references for the stone-milled flour industry and whole wheat noodles processing.The specific research results are as follows:1)As the particle size of WWF decreased,the moisture and protein content declined,and the damaged starch content increased.The 120 mesh WWF had the highest contents of K,Mg,Mn,Zn,total flavonoids,and total phenols,and the dough displayed better water absorption and resistance to destruction.The starch granule structure of the 160 mesh WWF was severely disrupted,and the degree of softening was significantly increased(P < 0.05),so the dough was easy to absorb water and rheology.When the particle size was increased to 120 mesh,the onset temperature,peak temperature,and conclusion temperature of WWF changed significantly.The functional properties analysis showed that the solubility and syneresis of WWF rose with decreasing particle size.The protein secondary structure of WWF was affected by particle size,and the contents of β-sheet and β-turn reduced with decreasing particle size.Scanning electron microscopy images displayed that the smaller the particle size of whole wheat flour,the higher the surface roughness of starch granules,and the finer the granule fragments.2)The decrease in particle size of WWF led to a decrease in the amount of starch wrapped in the protein network structure and an increase in the amount of dry matter dissolved in the noodle soup,so the cooking loss rate of dried noodles gradually increased.Salt increased the L* values and decreased the a* and b* values of the whole wheat dough sheet in the 0 h group to improve the color of the dried noodles.When the curing time was15 min,the water uptake ratio of dry matter of dried noodles was the highest and the cooking loss rate was the lowest.When water addition was low,the gluten protein was not hydrated enough,and the internal structure of the noodles was loose;when too much water was added,the hydration of the gluten increased,while the bonding force inside the dough became weaker,resulting in a decline in the quality of the noodles.The effect order of the factors on the comprehensive score of SDWWNs was WWF particle size > curing time >salt addition > water addition,and the optimal process of dried noodles was that WWF particle size was 120 mesh,salt addition was 0.85%,curing time was 15 min,and water addition was 37%.3)The total dietary fiber content of SDWWNs was significantly higher than that of DWNs and CDWWNs(P < 0.05).Compared with CDWWNs,the water uptake ratio of dry matter(154.68%)and tensile strength(24.03 g)of SDWWNs were significantly increased(P < 0.05),while the cooking loss rate(6.31%)and turbidity of noodle soup(0.085)were significantly reduced(P < 0.05).Compared with DWNs,two types of whole wheat noodles had less gluten network continuity and more holes due to the presence of bran,which prevented gliadin and glutenin from linking with each other through disulfide bonds.The protein secondary structure of the two types of raw and cooked whole wheat noodles was mainly dominated by the β‐sheet and β‐turn.The short-range ordered degree of starch molecules was significantly lower for the three cooked noodles compared to the raw noodles(P < 0.05).Prior to and after the in vitro simulated digestion,the DPPH radical scavenging activity,the hydroxyl radical scavenging activity,and the total reducing power of SDWWNs were the highest.The total dietary fiber content,amylose/amylopectin ratio,and resistant starch content of SDWWNs were higher,so the order of estimated glycemic index was SDWWNs < CDWWNs < DWNs.Overall,the SDWWNs had certain advantages in terms of cooking quality,texture properties,antioxidant activity,and controlling the glycemic response.