| Germination and fermentation play important roles in the growth and reproduction of plants and microorganisms.Grain germination or fermentation can alter the physicochemical properties of starch.Red yeast rice has a long history in our country.It is parasitized by Monascus on rice and has lipid-lowering effect.Microorganisms consume substances to obtain energy and change the nutrient content in rice through physiological activities.During the germination process of rice,many biological functional components can be produced.Germinated brown rice(GBR)is considered to be a natural functional food with high nutritional value.Fermentation of red yeast rice with GBR may further improve the nutritional value of red yeast rice,but the in vitro digestion rate of sprouted brown rice is higher than that of unsprouted rice,which may increase the risk of rapid rise in postprandial blood glucose.Resistant starch(RS),as a kind of starch,is not digested in the small intestine but can be fermented in the large intestine,and is benefit for human health.High RS rice has been proven to have the functions in balancing postprandial blood and improving low-density lipoprotein(LDL).But at the same time,the high RS rice has poor palatability,which affects the its’ acceptance and limits its’ application to a certain extent.In order to explore the changes of functional nutrients in rice under the conditions of germination and Monascus fermentation,and to further expand the application of high RS rice,four different RS content rice(Oryza sativa L.)R7954,GZ93,RS4 and sea rice were used in this study.The nutritional components,functional components and antioxidant properties of BR powder before and after germination and fermentation were analyzed.The results are as followings:1.The RS content in RS4 BR was 10.30%,lipid,total protein and total free amino acids(FAAs)were 4.35%,8.92% and 407.41 mg/100 g,respectively.After germination,the RS of the four rice species all decreased,but RS4 still remained at a high level of 4.09%.Meantime,the lipids in the four rice all decreased after germination,while the content of total FAAs increased significantly.RS4 had the highest total FAAs with 1269.91 mg/100 g.Among four rice varieties,RS4 was the easiest for Monascus fermentation and the fermentation was also the mostly complete.After direct fermentation of BR,the starch and protein contents of the four rice species decreased significantly,while the contents of RS,lipids,free sugars and total FAAs increased significantly.Among which,the RS of RS4 increased to 12.35%,the lipid of BR increased from 4.35% to7.57%,the free sugar increased from 0.82% to 1.17%,and the total FAAs increased to 1528.81mg/100 g.After germination and fermentation,the gelatinization temperature of red yeast rice was significantly reduced,making the food easier to cook,but the changes of other indicators were not as good as those of direct fermentation.2.The -aminobutyric acid(GABA)of RS4 is 251.38 mg/100 g.After germination,the GABA of all materials increases sharply,which is 2-5 times that of BR,of which GABA in RS4 increases to 759.29 mg/100 g.The content of β-glucan also increased significantly after germination,among which R7954 increased by 0.47%,and the content of GABA and β-glucan after fermentation was higher than that of GBR,among which,the GABA content of RS reached up to 835.53 mg/100 g.Combination of germination and fermentation,the GABA and free sugar of GZ93 was the highest,reach up to 1422.43 mg/100 g and 0.97% respectively.While the GABA content of other materials didn’t increase furtherly than that of GBR or direct fermentation,and was even lower than that of direct germination or fermentation;3.After germination,except that the total phenolic acid content of HSD did not increase significantly,the total phenolic acid content and total flavonoid content all increased significantly.Among them,RS4 had as high as 3.14 mg GAE/g total phenolic acid content,and 3.64 mg Rutin E/g total flavonoid content.After fermentation or fermentation combined with germination,free phenolic acid content,bound phenolic acid content,total phenolic acid content,total flavonoid content,ABTS antioxidant capacity,DPPH antioxidant capacity,p-coumaric acid content,ferulic acid content,sinapic acid content were significantly increased.,the free phenolic acids in RS4 After germination and fermentation were the highest with 8.11 mg GAE/g,and the total phenolic acids were also the highest,reached up to 9.25 mg GAE/g.A total of 11 phenolic acid monomers were detected in combination with phenolic acids,of which ferulic acid was the richest,followed by p-coumaric acid,sinapic acid and pro-coumaric acid.After germination,fermentation and germination and fermentation,the content of most phenolic acid monomers increased significantly,among which the content of ferulic acid in RS4 after fermentation and fermentation combined with germination reached up to 80.91 μg/g and 71.78 μg/g respectively,significantly higher than that of other three rice varieties.The antioxidant activities of ABTS and DPPH after germination,fermentation and germination and fermentation were increased compared with BR,and the antioxidant activities of ABTS and DPPH for RS4 after fermentation were 19.99 μmol Trolox/g and 11.56 μmol trolox/g,significantly higher than that of BR,which was 4.43 μmol Trolox/g and 3.6 μmol Trolox/g respectively.In conclusion,RS4 is easily fermented by Monascus,and its’ red yeast rice fermented by Monascus directly has the highest RS content(12.35%)and ferulic acid(80.91 μg/g),higher levels of lipids(7.57%),FAAs,GBGA(835.83 mg/100 g)and antioxidant capacity.What’s more,the gelatinization temperature of RS4 decreased after fermentation.Consuming RS4 red yeast rice may have the potent in reducing blood lipids and the incidence of obesity and diabetes.The research results provide a reference for further development of new antioxidant and hypolipidemic foods with high RS rice. |
PDF Full Text Request