| Due to the distinctive aroma and smooth texture,rice noodle is one of the most widely consumed staple foods in China.However,one of the main raw materials utilized in producing rice noodles is refined rice,which is processed with extreme precision and loses a lot of nutrients.Refined rice noodle has a low nutritional value and small amount of nutrient,which can lead to an imbalance in the body’s nutritional intake when consumed frequently.Germinated brown rice has a higher nutritional worth than refined rice,and adding it to rice noodles can significantly boost its nutritional quality.By researching the best process for germination of brown rice and optimizing the parameters and formulation of germinated brown rice noodles,the quality of germinated brown rice noodles could be enhanced,which will aid in improving the dietary structure of the Chinese people.The digestive state after intake of germinated brown rice noodles in the human gastrointestinal environment is yet unknown and requires more research.In this study,germination treatment was used to enhance the nutritional value of brown rice,and the ideal germination conditions for brown rice’s γ-aminobutyric acid enrichment were chosen.Based on these findings,single-factor and response surface experiments were used to investigate the effects of corn starch,refined rice/germinated brown rice ratio and ageing time on the breakage rate,cooking loss rate and sensory score of germinated brown rice noodles.The best formulation and process for the noodles were then identified.In vitro digestion studies were carried out to evaluate the phenolic release and antioxidant activity,as well as the starch and protein digesting properties,of germinated brown rice noodles with those of refined rice noodles and brown rice noodles.The results can provide some theoretical guidance and practical basis for the quality optimization and production of germinated brown rice noodles.The main study contents and results are shown below:1.Brown rice germination process and changes in nutritional and processing propertiesCold stress time,monosodium glutamate concentration,soaking time,and germination time were all controlled variables in a single-factor experiment,withγ-aminobutyric acid content in germinated brown rice serving as the investigated value.According to the findings,72 hours of germination time,12 hours of soaking time,1.5mg/m L of monosodium glutamate concentration,and 2 hours of cold stress time were the appropriate conditions to attain the maximal γ-aminobutyric acid content in germinated brown rice.The ideal germination conditions for brown rice’s γ-aminobutyric acid enrichment were chosen based on the actual production efficiency using the economics of orthogonal experiments: 2 h of cold stress,13 h of soaking,48 h of germination,and 1.5mg/m L of monosodium glutamate soaking solution concentration,at which time theγ-aminobutyric acid enrichment in brown rice reach to 118.48 mg/100 g,3.75 times higher than that before germination.At the same time,the reducing sugars and soluble protein content of the germinated brown rice significantly increased when compared to the normal raw brown rice,while the total starch,straight-chain starch,and total protein content decreased.The thermodynamic properties of starch pasting revealed a slight increase in the onset,peak,and end temperatures and a decrease in the pasting enthalpyΔH;the changes in the pasting characteristics were also markedly reduced.This demonstrated that germination can improve brown rice’s nutritional value while alter its thermodynamic and pasting characteristics.2.Development and assessment of the quality of germinated brown rice noodlesThe single factor experiment was designed using the addition amount of corn starch,the proportion of refined rice and germinated brown rice,the aging time as variables,the cooking loss rate,breaking rate,and sensory score of rice noodles as indicators.The findings demonstrated that adding 60% corn starch had the lowest breaking rate and the highest sensory score of germinated brown rice noodles.When the ratio of refined rice to germinated brown rice was 30:10,the breaking rate and cooking loss rate were lowest and the sensory ratings were greatest,and when the ageing time was 7 h,the breaking rate and cooking loss rate were lower but the ageing time had no discernible impact on the sensory score.A response surface test was carried out at the appropriate level to obtain the optimum formulation that was 61% corn starch addition,12.8% germinated brown rice addition and 6 h ageing time.This formulation was anticipated that the sensory score of the germinated brown rice noodles would be 91.2,while the actual score was 90.9,which was superior to the four control groups in terms of cooking quality and physicochemical properties.3.Study on the digestive characteristics of germinated brown rice noodlesWhen the gastrointestinal digestion of refined rice noodles,brown rice noodles,and germinated brown rice noodles were compared,it was discovered that the latter had lower starch hydrolysis rate,rapidly digestible starch content,hydrolysis index,and glycemic index,as well as the higher slowly digestible starch and resistant starch content,which were 1.07,1.23 and 1.06,1.16 times higher than those of refined rice noodles and brown rice noodles respectively.Additionally,the latter’s protein digestibility and release of free amino acids was second only to that of refined rice noodles,which indicated that consuming germinated brown rice noodles could help to stabilize blood glucose and protein absorption and utilization after meals.While the amount of phenolics released from germinated brown rice noodles is 1.22 and 1.12 times higher than that of refined rice noodles and brown rice noodles respectively,and the antioxidant capacity is also stronger than the other two types of rice noodles. |
