Bioaccessibility of defatted lupin seed phenolic compounds in a standardized static in vitro digestion system.

Phenolic compounds are secondary plant metabolites whose beneficial health effects make them of intense interest to researchers. The aim of the study presented here was to evaluate the change in the phenolic compound profile of lupin seed in in vitro digestion. The most abundant phenolic compounds in undigested lupin seeds were mostly apigenin derivatives. The in vitro digestion of lupin seeds resulted in qualitatively altered phenolic compound profiles. Approximately 80% of phenolic compounds were released from lupin seeds during the in vitro digestion, which simulated gastric processes. Continued digestion, imitating the intestinal phase, additionally increased the bioaccessibility of lupin seed polyphenols by about 10%. The in vitro gastrointestinal model was also used to elucidate how the content of native phenolic compounds affects the digestion susceptibility of lupin seed proteins. An inverse correlation between protein digestibility and phenolic compound content, was also demonstrated.

Water Deficit Affects Primary Metabolism Differently in Two Lolium multiflorum/Festuca arundinacea Introgression Forms with a Distinct Capacity for Photosynthesis and Membrane Regeneration.

Understanding how plants respond to drought at different levels of cell metabolism is an important aspect of research on the mechanisms involved in stress tolerance. Furthermore, a dissection of drought tolerance into its crucial components by the use of plant introgression forms facilitates to analyze this trait more deeply. The important components of plant drought tolerance are the capacity for photosynthesis under drought conditions, and the ability of cellular membrane regeneration after stress cessation. Two closely related introgression forms of Lolium multiflorum/Festuca arundinacea, differing in the level of photosynthetic capacity during stress, and in the ability to regenerate their cellular membranes after stress cessation, were used as forage grass models in a primary metabolome profiling and in an evaluation of chloroplast 1,6-bisphosphate aldolase accumulation level and activity, during 11 days of water deficit, followed by 10 days of rehydration. It was revealed here that the introgression form, characterized by the ability to regenerate membranes after rehydration, contained higher amounts of proline, melibiose, galactaric acid, myo-inositol and myo-inositol-1-phosphate involved in osmoprotection and stress signaling under drought. Moreover, during the rehydration period, this form also maintained elevated accumulation levels of most the primary metabolites, analyzed here. The other introgression form, characterized by the higher capacity for photosynthesis, revealed a higher accumulation level and activity of chloroplast aldolase under drought conditions, and higher accumulation levels of most photosynthetic products during control and drought periods. The potential impact of the observed metabolic alterations on cellular membrane recovery after stress cessation, and on a photosynthetic capacity under drought conditions in grasses, are discussed.

Identification of saponins from sugar beet (Beta vulgaris) by low and high-resolution HPLC-MS/MS.

We profiled triterpene saponins from the roots of sugar beet Beta vulgaris L. cultivars Huzar and Boryna using reversed-phase liquid chromatography combined with negative-ion electrospray ionization quadrupole mass spectrometry. We tentatively identified 26 triterpene saponins, including 17 that had not been detected previously in this plant species and 7 saponins that were tentatively identified as new compounds. All observed compounds were glycosides of five different aglycones, of which gypsogenin and norhederagenin are reported for the first time in sugar beet. Thirteen of the saponins detected in sugar beet roots were substituted with dioxolane-type (4 saponins) or acetal-type (9 saponins) dicarboxylic acids. Among the 26 detected saponins, we identified 2 groups of isomers distinguished using high-resolution mass measurements that were detected only in the Huzar cultivar of sugar beet.

Characterisation and identification of triterpene saponins in the roots of red beets (Beta vulgaris L.) using two HPLC-MS systems.

Triterpene saponins are important bioactive constituents with an enormous variety in structure widely distributed in many plants. Here, we profiled triterpene saponins from the skin and flesh of red beetroot Beta vulgaris L. cultivars Nochowski from 2012 and 2013 season using reversed-phase liquid chromatography combined with negative-ion electrospray ionisation quadrupole mass spectrometry. We tentatively identified 44 triterpene saponins, of which 37 had not been detected previously in the root of red beets and 27 saponins were tentatively identified as potentially new compounds. All observed compounds were glycosides of four different aglycone structures, of which akebonoic acid and gypsogenin were not detected previous in red beetroot. Based on the high-resolution mass measurements among these 44 detected saponins 10 groups of isomers were identified. We report for the first time that 18 saponins with dioxolane-type (2 saponins) and acetal-type (16 saponins) substituents were detected in the roots of red beet.