Structure characterization of the central repetitive domain of high molecular weight gluten proteins. II. Characterization in solution and in the dry state

The structure of the central repetitive domain of high molecular weight (HMW) wheat gluten proteins was characterized in solution and in the dry state using HMW proteins Bx6 and Bx7 and a subcloned, bacterially expressed part of the repetitive domain of HMW Dx5. Model studies of the HMW consensus peptides PGQGQQ and GYYPTSPQQ formed the basis for the data analysis. In solution, the repetitive domain contained a continuous nonoverlapping series of both type I and type II β-turns at positions predicted from the model studies; type II β-turns occurred at QPGQ and QQGY sequences and type I β-turns at YPTS and SPQQ. The subcloned part of the HMW Dx5 repetitive domain sometimes migrated as two bands on SDS-PAGE; we present evidence that this may be caused by a single amino acid insertion that disturbs the regular structure of β-turns. The type I β-turns are lost when the protein is dried on a solid surface, probably by conversion to type II β-turns. The homogeneous type II β-turn distribution is compatible with the formation of a β-spiral structure, which provides the protein with elastic properties. The β-turns and thus the β-spiral are stabilized by hydrogen bonds within and between turns. Reformation of this hydrogen bonding network after, e.g., mechanical disruption may be important for the elastic properties of gluten proteins

Multi-response kinetic modelling of the formation of five Strecker aldehydes during kilning of barley malt

International audienceStrecker aldehydes are responsible for the characteristic aroma of malts, but also important aroma compounds in beer. In malt, they are formed during the curing stage of kilning. The formation of five Strecker aldehydes (2-methylpropanal, 2-methylbutanal, 3-methybutanal, phenylacetaldehyde and methional) during this process was studied at pilot scale. Green malts were dried and cured at different temperatures (65, 78 and 90 °C) isothermally for 8.4 h. Multi-response kinetic modelling was used to develop a mathematical model based on precursors concentration, Amadori rearrangement products (ARP), Strecker aldehydes, temperature and time. This model demonstrated that the formation of Strecker aldehydes in malt was controlled from the formation of two intermediates: ARP and short chain dicarbonyls (SCDC). The kinetic model proposed in this study will help maltsters and researchers understand and manipulate the formation of these compounds in malt and the organoleptic quality of the beers brewed from them

Philanthropy in Contemporary Africa: A Review

Despite the availability of a wide range of literature on what is can be construed to be philanthropic behaviour in Africa, there is limited conceptual discussion on what constitutes philanthropy in African context(s). Yet, philanthropic behaviour is culturally rooted phenomena manifesting in diverse forms, expressions, and models. This review contributes to a growing body of literature on conceptions and manifestations of African philanthropy. The review illustrates a complex plurality of actions that fall under cultures and practices of giving in Africa. These include the giving of money, time, knowledge, influence and visibility in support of a cause, valuable goods, and body parts/organs from living and dead. While some of these actions conform to dominant Western notions of philanthropy, others do not. From an analysis of these practices, this paper proposes that African philanthropy can be conceptually structured on the basis of spheres of philanthropic practice, and the underlying bases and motivations for philanthropy. On spheres of philanthropic practice, at least three forms of philanthropy exist: institutional (formal); non-institutional (non-formal/informal/direct); and a hybrid form that blends practices from the formal and informal spheres. On motivations for giving, the predominant forms are based on mutuality, solidarity and counter-obligation inherent in collectivist and humanistic African philosophies of life. Further, motivations are drawn from religious obligations, institutional requirements on corporate bodies, and institutional arrangements in the development process. There are, nonetheless, significant overlaps between spheres of practice and motivations in contemporary philanthropic practices in Africa. For instance, philanthropic culture in Africa manifests as religious giving, donations to individuals or institutions, mutual aid, reciprocal, self-help revolving fund organisations, corporate social responsibility activities, and individual/family donations to public benefit organisations. These practices highlight a rich tapestry of spheres of practice and motivations for giving practices, where the wealthy and the poor are equally involved. The review, concentrates (by choice) on giving of money and time (volunteering, especially informal volunteering) due to dearth of academic literature on other forms of giving as philanthropy in Africa