title: Lactic acid and thermal treatments trigger the hydrolysis of myo-inositol hexakisphosphate and modify the abundance of lower myo-inositol phosphates in barley (Hordeum vulgare L.).
abstract: Barley is an important source of dietary minerals, but it also contains myo-inositol hexakisphosphate (InsP6) that lowers their absorption. This study evaluated the effects of increasing concentrations (0.5, 1, and 5%, vol/vol) of lactic acid (LA), without or with an additional thermal treatment at 55°C (LA-H), on InsP6 hydrolysis, formation of lower phosphorylated myo-inositol phosphates, and changes in chemical composition of barley grain. Increasing LA concentrations and thermal treatment linearly reduced (P<0.001) InsP6-phosphate (InsP6-P) by 0.5 to 1 g compared to the native barley. In particular, treating barley with 5% LA-H was the most efficient treatment to reduce the concentrations of InsP6-P, and stimulate the formation of lower phosphorylated myo-inositol phosphates such as myo-inositol tetraphosphate (InsP4) and myo-inositol pentaphosphates (InsP5). Also, LA and thermal treatment changed the abundance of InsP4 and InsP5 isomers with Ins(1,2,5,6)P4 and Ins(1,2,3,4,5)P5 as the dominating isomers with 5% LA, 1% LA-H and 5% LA-H treatment of barley, resembling to profiles found when microbial 6-phytase is applied. Treating barley with LA at room temperature (22°C) increased the concentration of resistant starch and dietary fiber but lowered those of total starch and crude ash. Interestingly, total phosphorus (P) was only reduced (P<0.05) in barley treated with LA-H but not after processing of barley with LA at room temperature. In conclusion, LA and LA-H treatment may be effective processing techniques to reduce InsP6 in cereals used in animal feeding with the highest degradation of InsP6 at 5% LA-H. Further in vivo studies are warranted to determine the actual intestinal P availability and to assess the impact of changes in nutrient composition of LA treated barley on animal performance.
authors: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, Vetmeduni Vienna, Vienna, Austria; University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, Vetmeduni Vienna, Vienna, Austria.
authors: Barbara U
authors: BU
authors: Metzler-Zebeli
authors: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, Vetmeduni Vienna, Vienna, Austria.
authors: Kathrin
authors: K
authors: Deckardt
authors: Institute of Animal Nutrition, University of Hohenheim, Stuttgart, Germany.
authors: Margit
authors: M
authors: Schollenberger
authors: Institute of Animal Nutrition, University of Hohenheim, Stuttgart, Germany.
authors: Markus
authors: M
authors: Rodehutscord
authors: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, Vetmeduni Vienna, Vienna, Austria.
authors: Qendrim
authors: Q
authors: Zebeli
mesh_terms: D001467:Hordeum / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D006358:Hot Temperature; D006868:Hydrolysis / Q000187:drug effects / Q000528:radiation effects; D007295:Inositol Phosphates / Q000378:metabolism*; D010833:Phytic Acid / Q000494:pharmacology*; D013696:Temperature
chemical_list: D007295:Inositol Phosphates; C013571:inositol pentaphosphate; D010833:Phytic Acid