Eva-Lotta Bergman

Hydrothermal treatment and malting of barley improved zinc absorption but not calcium absorption in humans

Objective: To study whether hydrothermal treatment or malting of barley (cv. Blenheim) improves zinc and calcium absorption in humans.Design: Two groups of 10 and 12 healthy subjects, respectively, were in a period of 2 months in a fasting state, served two single meals each containing porridge or breakfast cereals prepared from processed or unprocessed (control) barley (60 g). The meals included 200 g of milk, extrinsically labelled with 65Zn and 47Ca. Whole-body retention of both minerals was measured.Setting: The study was carried out at the Department of Radiation Physics, Sahlgrenska University Hospital, Göteborg.Subjects: The subjects were recruited among students at the Göteborg University. None dropped out.Interventions: The activities of 65Zn and 47Ca were measured by whole-body counting four to five times over a 4-week period after each meal.Results: Zinc absorption from hydrothermally treated barley porridge, containing 28 mg P as inositol tri- to hexaphosphates (InsP3–InsP6), was significantly higher (P<0.001) than from control porridge containing 111 mg P as InsP3–InsP6, 25.2±6.9 vs 11.0±2.5% (n=12). Calcium absorption did not differ (P>0.05), 21.1±6.8 vs 19.5±4.7% (n=12). Zinc absorption from breakfast cereals of malted barley with phytase activity and containing 70 mg P as InsP3–InsP6, was significantly higher (P<0.05) than from flakes of barley, containing 108 mg P as InsP3– InsP6 and no phytase activity, 22.9±5.8 vs 14.8±4.6% (n=10). The calcium absorption was 21.3±6.5 vs 18.5±4.3% (n=10) and did not differ significantly (P>0.05).Conclusions: Improvements of zinc absorption in breakfast meals can be achieved by optimised hydrothermal treatment or malting of barley. Calcium absorption was not influenced in the meals in this study.Sponsorship: Supported by Semper AB, Sweden, Oy Lahden Polttimo, Finland, the SL-Foundation, Sweden, Swedish National Board for Industrial and Technical Development (NUTEK), the Nordic Industrial Foundation, Swedish Council for Forestry and Agricultural Research (SJFR, project no 50.0306/97).

Optimization of temperature, time, and lactic acid concentration to inactivate lipoxygenase and lipase and preserve phytase activity in barley (cv. Blenheim) during soaking

ABSTRACT A barley-soaking process was studied to find conditions that inactivate the prooxidative enzyme lipoxygenase and the lipolytic enzyme lipase but preserve phytase activity to develop possible procedures for production of barley products with potentially high mineral bioavailability and good oxidative stability. Lactic acid concentration, temperature, and soaking time were studied. The study was done using a multivariate experimental design. Lactic acid concentration varied between 0 and 1%, temperature varied between 45 and 70°C, and soaking time varied between 30 and 120 min. Although conditions under which lipoxygenase was inactivated were found, total inactivation of lipase was not obtained. Total lipoxygenase inactivation with 60% remaining phytase activity was reached after soaking in 1% lactic acid at suitable time-temperature combinations of 70–110 min and 53–58°C.

Development of Predictive Models for Optimization of Phytate Degradation in Wheat and Rye During Hydrothermal Processing

ABSTRACT Whole kernels of wheat (Triticum aestivum ‘Kosack’), rye (Secale cereale ‘Motto’) and rice (Oryza sativa) were hydrothermally treated to reduce the phytate content. The hydrothermal processes used in this study included alternating wet and dry steeping periods. Two hydrothermal processes were used for wheat and rye with two and three wet and dry steeping steps, respectively. The process using two wet and dry steeping steps (process 1) was optimized for phytate reduction with respect to temperature during the process and lactic acid concentration used in the wet steeping steps. Optimal conditions for phytate breakdown in wheat and rye in process 1 were 55°C during the whole process and 1.3–1.5% lactic acid solution as the soaking agent in the wet steeping periods for wheat and 1.3% for rye. The hydrothermal process with three wet and dry steeping periods for wheat and rye (process 2) showed that the temperature used in the third wet and dry steeps did not significantly influence (P > 0.05) the phy...