Effect Of Airflow Classify-impact Mill On The Quality Of Buckwheat Flour And Noodle

Tartary buckwheat(Fagopyrum tartaricum Gaertn.)is a kind of Chinese traditional minor cereals,approved by Food and Agriculture Organization(FAO)as a unique food medicine dual-use cereal crop.Tartary buckwheat seed has high level of bioactive nutrients and components(e.g.,starch,dietary fiber and polyphenols,flavonoids,protein and other ingredients)and has many biological functions,such as anti-inflammatory and bacteria-inhibiting,antihypertensive,antihypercholesterolemic,antioxidative as well as improving diabetes,cardiovascular disease and other chronic diseases.Milling is an important pretreatment process for further processing of buckwheat.The main problem of traditional milling equipment is that if the degree of refinement of flour is improved,the loss of nutritional and functional components in tartary buckwheat seed will be serious.On the contrary,if the degree of refinement of flour is lower,which will result in rough taste of buckwheat products and low customers acceptability.Therefore,it is very important to select an appropriate milling equipment which can not only retain the nutritional and functional components of tartary buckwheat flour,but also reach the fine grinding level.In addition,noodle is one of the main products of tartary buckwheat,and at the same time,the convenience of it has been widely recognized by consumers.Accordingly,this paper described a new type of milling equipment(airflow classify-impact mill)for grinding buckwheat seeds as well as the comparison between the product and the common flour made by a universal high-speed grinder.In order to obtain a flour with high retention of nutrition and functional components and improved processing quality,the flour prepared by two kinds of equipments was investigated in terms of the basic nutrients content,the bioactive nutrients content,antioxidant property and processing characteristic.Wheat noodle was used as control,the noodles made from them were analyzed of cooking quality,texture quality,sensory quality and the characteristics of starch digestion in vitro.Results of this study will provide theoretical and technical support for the development of high quality and acceptable buckwheat noodle.The main results of the study were as follows:(1)The airflow classify-impact mill had a significant effect on basic nutrients content of buckwheat flour.Especially in the residue of crude fat,crude protein and crude fiber,the ultrafine flour milled by the new equipment was remarkably higher than the common flour,which was 1.42 times,1.24 times,and 8.07 times,respectively.(2)The ultrafine flour contained more phenolic compounds and flavonoids,and the contents were up to 1.94 times,2.19 times when the contents of total flavonoids and total phenols in common flour were 77.84±1.31 mg rutin eq./100 g DW,527.19±2.21 mg gallic acid eq./100 g DW,respectively.With regard to the results by HPLC analysis,only three polyphenol compounds(rutin,ellagic acid and quercetin)were identified and revealed that the contents of the three substances in ultrafine flour were significantly higher than that of common flour.(3)The range of particle size distribution of ultrafine flour made by airflow classify-impact mill was smaller and the powder was more delicate.At the same time,the water absorption,solubility and expansion degree of the ultrafine flour were higher than that of common flour.The results of gelatinization property showed that The ultrafine buckwheat flour had better thermal stability,stronger gelling ability and non-aging ability.All of the above results indicated that the ultrafine buckwheat flour had better processing characteristics.(4)Through the analysis of the cooking quality,texture quality and sensory quality of three different kinds of noodles,it was found that the noodle made by ultrafine buckwheat flour had the unique flavor of buckwheat and its stretchability was improved,but the only drawback was the taste slightly sticky.The results showed that the starch hydrolysis rate(52.66%)was slightly lower than that of common buckwheat noodle(53.45%).