MODIFIED FLUORIMETRIC FLOW-INJECTION-ANALYSIS (FIA) METHOD FOR THE DETERMINATION OF (1–3) (1–4)–B—D—GLUCAN

A simple system has been constructed for the quantitative determination of barley β-glucans. Measurements were made by the flow-injection-analysis (FIA) technique using the fluorescent dye Calcofluor as a specific reagent for (1·3) (1·4)–B—D—linkages. In this paper a single-line system is described involving only one pump samples of β-glucan being directly injected into the reagent stream. The reaction results in an increased intensity of fluorescence detected by a flow-through-cell fluorimeter and evaluated as peak heights or peak areas by a printer-plotter. The analysis is completed within 20s. The operational parameters were set during an optimization procedure.     

Lycopene (Z) – isomers enrichment and separation

(All‐E)‐ Lycopene undergoes geometrical isomerisation into (Z)‐lycopene isomers with thermal treatment. Influence of three isomerisation methods including ethyl acetate reflux, microwave‐assisted reflux and ultrasound/microwave‐assisted reflux, and isolation of (all‐E)‐lycopene from other carotenoids and (Z) lycopene isomers through selective inclusion by deoxycholic acid (3α, 12α dihydroxy‐5βcolan‐24‐oic‐acid, DCA) were investigated. The results showed that microwave and ultrasound/microwave‐assisted reflux were not significantly different at P < 0.05, but both were significantly different (P < 0.05) over refluxing in ethyl acetate, proportion of (Z)‐lycopene isomers reached 54% after refluxing for 5 h. Heterogeneous mixture of isomerised tomato oleoresin containing 54% (Z)‐lycopene isomers and 40% (all‐E)‐lycopene and deoxycholic acid in dichloromethane was incubated at 25 °C for 2 h. Then, the mixture was filtered and from the filtrate 96.6% (Z)‐isomers enriched lycopene was obtained. The processes can be used in the production of enriched (Z)‐lycopene isomers for food supplements and functional food industry as a natural bioactive ingredient.     

Heavy metals (Pb,Cu, Zn and Cd) in the system soil – grapevine – grape

An Erratum has been published for this article in Journal of the Science of Food and Agriculture 79(15)1999, 2122. The investigation was carried out in the period 1991–1995 in a region with a major industrial pollutant, the Non‐Ferrous‐Metal Works, and a region with no industrial pollutants (as a control). The heavy metal content in soil, roots, annual shoots and perennial parts of grapevine, leaves, grapes and wine, was determined. Soil samples and roots of the rootstock Kober 5BB were taken at 10 cm intervals from depths of 0–100 cm. Roots were divided by thickness in fractions at 1 mm intervals. The shoots, bark, vascular tissue, wood, core and diaphragm were investigated. The leaf analyses included leaf blade and leaf petioles, and those of grapes, berry‐free raceme (washed in a lot of water and unwashed). Berries were analysed (the berry skin, the pulp and the seeds). The results obtained for the Pb, Cu, Zn and Cd contents in the grapevine roots show that they depend significantly both on their amounts in the soil and the age of the roots. The main parts of the heavy metal amounts taken by the roots of the grapevine from the soil are fixed and accumulated in the young feed rootlets (with diameters of 1 mm), and small amounts of them move through the conducting system to the older, larger diameter root system. The experimental data obtained for the presence of Pb, Cu, Zn and Cd in the separate tissues and organs of grapevines grown in an industrially polluted region showed that their amounts were mainly due to the heavy‐metal‐containing aerosols falling from the atmosphere. Part of them, however, got into the soil, and from there, even if in minimal amounts, penetrated via the root system into the grapevine plants and accumulated into their different overground parts. © 1999 Society of Chemical Industry     

The (1–3, 1–4)‐β‐Glucanases in Malting Barley: Enzyme Survival and Genetic and Environmental Effects

Eighteen barley genotypes used in Brazilian malting barley breeding programs were characterized in relation to (1–3, 1–4)‐β‐glucanase activity in green and kilned malt. They were tested to determine the loss of enzyme activity during kilning in the malting process and the environmental effects on enzyme activity were measured. The genotypes analyzed showed great variation regarding the enzyme activity in both kinds of malt, in a range from 531.94 to 934.31 U/kg in green malt, and from 187.02 to 518.40 U/kg in dry malt. The mean enzyme activity loss during kilning was close to 60%, very similar to the results obtained in other studies. The loss among genotypes varied from 8.04% to 71.54%. The enzyme activity varied significantly under the different environments tested, showing existence of environmental effects on the genotypes analyzed. Embrapa 127 was the genotype that exhibited the highest enzyme activity in finished malt although it had shown a low activity in green malt, reflecting a negligible loss of activity during kilning. The data indicate promising results to malting barley breeding due to the wide variability exhibited by genotypes as to enzyme activity and levels of isoenzyme with high thermostability.