Kerstin Fredlund

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).

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...

Determination of the retention of 47Ca by whole-body counting

Retention of intravenously or orally administered 47Ca in the human body are described by a two-parameter function. It is then sufficient to make only a few whole-body measurements to determine the retention function, avoiding faeces sampling and stool markers. Seven days after intake the non-absorbed calcium was excreted and the model agreed with the measured relative retention. Absorption of calcium could then, in some cases (e.g. comparative studies), be described by relative retention at the 7th day after intake.

Extrinsic labelling of zinc and calcium in bread.

This study investigated the effect of different means of extrinsic administration of 65Zn and 47Ca in white wheat flour bread on the measured absorption. Eight healthy subjects were served 80g of labelled bread as a standardized breakfast after an overnight fast on three occasions. Extrinsic labelling of the meals with 65Zn and 47Ca was done in three ways: (a) by adding the isotopes to the bread 16h before it was served, (b) by adding the isotopes shortly before serving or (c) by adding the isotopes to the water used in dough making. Zinc and calcium chloride corresponding to 3.2mg (49 micromol) zinc and 275mg (6.9mmol) calcium in one portion were added to the dough. Whole-body retention was measured by whole-body counting. The fractional absorption of zinc was (a) 0.243 +/- 0.122, (b) 0.217 +/- 0.101 and (c) 0.178 +/- 0.063 (mean +/- SD), and the fractional absorption of calcium (expressed as calcium retention on day 7) was (a) 0.351 +/- 0.108, (b) 0.357 +/- 0.131 and (c) 0.334 +/- 0.117 (mean+SD). No significant difference (p > 0.05) was seen between the different ways for either zinc nor calcium.