| Adlay is an annual or perennial herb.During the process of adlay refining,a large number of adlay bran is produced,which still need to be developed and utilized.In this paper,defatted adlay bran was taken as the research object.Firstly,the effects of different incubation time on nutritional composition and biological activity of defatted adlay bran were studied.Then,the effects of incubation with protease addition treatment on the release of phenolic compounds from defatted adlay bran were investigated.Furthermore,the effects of synergistic treatment of incubation and hydrothermal on the nutritional value of adlay bran water extract were explored.Finally,the characteristics of inclusion complex ofβ-cyclodextrin(β-CD)and adlay bran polyphenols(ABP)were discussed.This study will provide a theoretical basis for the development and utilization of adlay bran.1.The defatted adlay bran was incubated for different time.The results showed that the nutritional value and biological activity of defatted adlay bran were significantly improved by incubation.After incubation,the p H of defatted adlay bran decreased significantly(P<0.05),while total titrated acid and the content of reducing sugar increased significantly(P<0.05).After incubation,the adlay bran proteins were degraded obviously,the proportions of high molecular weight peptides decreased gradually,while the proportions of low molecular weight peptides increased gradually(P<0.05),and the content of total free amino acids increased by 9.84 times after incubation for 12 h(P<0.05).Seven phenolic compounds were detected in adlay bran,mainly in the form of free state,and most of them increased significantly after incubation(P<0.05).In addition,the contents of free and bound phenolics and free antioxidant activity of adlay bran increased significantly with the increase of incubation time(P<0.05).2.Defatted adlay bran was incubated with protease addition.The results showed that the addition of different proteases could promote the release of phenolic compounds from defatted adlay bran and improve its antioxidant activity.Compared with the single incubation,the structure of defatted adlay bran was looser and the protein was further degraded by incubation with protease addition.The content of free phenolic acid in defatted adlay bran was further increased after incubation with protease addition,but the content of bound phenolic acid showed no significant changes(P>0.05).The contents of free phenolic and flavonoid increased by 3.9%-19.2%and 21.9%-39.0%respectively(P<0.05),while the contents of bound phenolic and flavonoid were not affected(P>0.05).In addition,the antioxidant activity of defatted adlay bran was enhanced by incubation with protease addition,and the free ferric reducing antioxidant power(FRAP)and ABTS·~+scavenging ability were increased by 1.7%-14.6%and 1.5%-8.9%respectively compared with those of single incubation(P<0.05).Compared with other proteases,neutral protease had better synergistic effect on enhancing antioxidant activity of defatted adlay bran.3.Defatted adlay bran was treated with the combination of incubation and hydrothermal.The results showed that the combination of incubation and hydrothermal treatment could significantly improve the nutritional value of water extract of defatted adlay bran.After incubation,the total free amino acid content of water extract increased by 1.94 times(P<0.05),but decreased with the extension of hydrothermal treatment time.The proportions of low molecular weight peptides increased significantly(P<0.05)after incubation,while the proportions of high molecular weight peptides decreased significantly(P<0.05).However,after hydrothermal treatment,the proportions of peptides with different molecular weight distribution did not change significantly(P>0.05),but their areas increased significantly(P<0.05).After incubation and hydrothermal treatment,the total phenolic content of the aqueous extract increased significantly(P<0.05),and the FRAP,DPPH and ABTS·~+scavenging abilities also increased significantly(P<0.05).In addition,both incubation and hydrothermal treatment could increase the tyrosinase and xanthine oxidase inhibitory activities of the adlay bran water extract.4.An inclusion complex was prepared withβ-CD as the host and ABP as the guest.The results showed that ABP/β-CD inclusion complex was successfully prepared by freeze-drying method.After inclusion withβ-CD,the surface morphology of ABP changed obviously,the crystallinity decreased and the thermal stability improved.Compared with those of ABP,the FRAP and ABTS·~+scavenging activity of ABP/β-CD inclusion complex were increased by 5.6%and8.9%(P<0.05),respectively.In addition,the stability of ABP aqueous solution was significantly improved after inclusion withβ-CD,and the retention rate of polyphenols reached 95%after 48 h of light exposure,which was 1.20 times of that of ABP(P<0.05). |
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