The mean dietary exposure to the nutrient elements iodine, Fe, Se and Na by eight age-sex groups of the New Zealand population was estimated from foods purchased and prepared as for consumption. A total of 968 samples comprising 121 foods were collected and analysed. Mean daily exposures were calculated from mean concentration levels of the selected nutrients in each food combined with simulated diets for a 25 þ -yearold male and female, a 19-24-year-old male, a 11-14-year-old boy and girl, a 5-6-year-old child, a 1 -3-year-old toddler and a 6-12-month-old infant. Food concentrations and dietary exposures are reported and compared with nutrient reference values (for example, recommended daily intakes, adequate intakes or upper limits). Dietary iodine exposures for all age -sex groups were well below recommended levels and have steadily decreased since 1982, raising concern especially for the physical and mental development of infants and young children. Fe exposures meet the recommended daily intake for the average male and 11-14 year olds but are only about half that recommended for adult females. Se exposure is about 20 % less than optimal for females. Na exposures, excluding discretionary salt, are above the acceptable exposure level for all age -sex groups, and exceed the upper intake limits for 25 þ -year-old males, 19-24-year-old young males, and 11-14-year-old boys and girls by up to 125 % for an average consumer.

Simple reproducible methods using a minimum of equipment are described for the routine analysis of soluble sugars, starch, total nitrogen and phosphorus in plant material. Soluble sugars are extracted with 62.5 % methanol and the sugars estimated by the phenol-sulphuric acid technique. Starch in the residual tissue is digested by an amyloglucosidase and glucose is determined by a glucose oxidase method. Both nitrogen and phosphorus are assayed after wet ashing the plant tissue-nitrogen by the phenol-hypochlorite reaction and phosphorus after reduction of the phosphomolybdic acid with ascorbic acid/antimony potassium tartrate.

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A spectrophotometric method for determining soluble protein has been applied to the measurement of soluble nitrogen (SN) in micromalts from a barley breeding programme. A regression equation between wort SN values, measured by the KJeldahl method, and the absorbance difference (A21B-A22B|) of diluted wort samples was prepared and then used to predict SN levels of 353 worts produced from breeding material from a diverse genetic background. These data were highly correlated with those obtained from the Kjeldahl method (r = 0.952***). A second calibration equation relating wort absorbance at a single wavelength (A21B) to Kjeldahl nitrogen data was able to predict wort SN values with equal accuracy compared with the relationship based on absorbance difference (A21B-A22b)-Here, the correlation between the two data sets was r = 0.953*** (n a 353). The spectrophotometric method is a rapid and simple means of measuring wort SN in the large numbers of samples generated by barley breeders and the single wave-length measurement offers a particularly efficient method of screening the very small wort volumes produced from test tube-scale mashes.