Isolation and identification of lutein esters, including their regioisomers, in tritordeum (×Tritordeum Ascherson et Graebner) grains: Evidence for a preferential xanthophyll acyltransferase activity

Liquid chromatography in conjunction with UV-visible spectroscopy and atmospheric pressure chemical ionisation (APCI) mass spectrometry has been used for the structural assignment of the lutein esters, including the regioisomeric forms, naturally occurring in the endosperm of tritordeum (×Tritordeum Ascherson et Graebner), a novel cereal. The distinctive mass spectrometry fragmentation pattern of lutein, characterized by a favored loss of the moieties at the position 3' of the ε-end ring, allowed an unambiguous structural identification of four monoesters (lutein 3'-O-linoleate, lutein 3-O-linoleate, lutein 3'-O-palmitate, lutein 3-O-palmitate) and four diesters (lutein dilinoleate, lutein 3'-O-linoleate-3-O-palmitate, lutein 3'-O-palmitate-3-O-linoleate, lutein dipalmitate). This is the first time that the regioisomers of carotenoid esters have been identified in a cereal. Evidences for a preferential xanthophyll acyltransferase activity regarding the position (3 or 3') and the acyl moiety are discussed. Further studies should be carried out in order to identify the acyltransferase enzymes and the acyl donor molecules involved in the xanthophyll esterification process.     

Adequacy of wholegrain non-wheat flours for layer cake elaboration

Flours (white and wholegrain flours) from wheat, rye, triticale, barley and tritordeum were used to elaborate layer cakes. The pasting properties (RVA) and the water-absorption (doughLab) of flours were analyzed. The batter characteristics (density, G′, G″, tan δ, consistency and flow index), and the cake characteristics (cake volume, crumb and crust colour and texture after 1 and 7 days) were studied. A sensorial evaluation of the cakes was also performed. Wholegrain flours showed higher pasting temperature and water-absorption, but lower peak time and viscosity than white flours. Its batters showed lower density and consistency and higher G′, G″, tan δ and n values. Wholegrain cakes showed lower specific volume, symmetry, colour characteristics, and staling rate but higher initial firmness. Considering the different cereals, barley showed the most different behaviour in flour, batter and cake characteristics. DoughLab analysis was very interesting to understand the adequacy of flours to cake elaboration, since significant correlations were found between water-absorption and specific volume, symmetry and firmness. Little differences in the consumer test were obtained between wheat and non-wheat cakes. Wholegrain non-wheat cakes could be a good alternative to white flour wheat cakes, due to their adequate technological properties and their nutritional advantages.