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Mineral elemental concentrations of 50 Chinese medicinal herbs in acid digests were determined by flame atomic absorption spectroscopy. The data were subjected to chemometric assessment to understand the association between the elements and to classify the herbal samples. Chemometric techniques, such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used as classification techniques. PCA generated two principal components that explained 62% of the total variance in the data. HCA disclosed two significant groups of samples based on their elemental concentrations.

This study investigated the removal of N-nitrosodimethylamine (NDMA) by an adsorption mechanism using commercially available activated carbons and surface-modified activated carbons. The effects of the modification on the properties of the activated carbon were studied by N(2) adsorption/desorption, Diffuse Reflectance Infrared Fourier Transmission (DRIFT) analysis and X-Ray Photoelectron Spectroscopy (XPS). Adsorption experiments revealed that the activated carbons demonstrated a greater capacity for NDMA adsorption capacity than can be achieved using zeolite. The equilibrium data was fitted to the Freundlich equation and it was found that the adsorption capacity was significantly influenced by the micropore size, relative pore volume and surface characteristics. Adsorption experiments were conducted using unmodified and modified activated carbons. The results indicated that the adsorption capacity of NDMA can be significantly improved by heat treatment and doping of TiO(2) particles. This was because the surface treatments yielded more hydrophobic sites and fewer oxygen-containing surface functional groups, and consequently an increased capacity for NDMA adsorption.

Sultana grapevines (Vitis Vinifera L. cv. Sultana syn. Thompson Seedless) were subjected to four shading regimes: 50% shading (1), 25% shading (2), fully exposed-top of canopy (3) and beneath canopy (4) and harvested early (21 February) and late (13 March) in the 1996/1997 sultana season. Grapes from each of the eight field-treatment combinations represented a range of maturities (14.4 to 23.50°Brix). Grape samples from each of the treatments were dipped and dried to 18% moisture, with half of each of the sultana samples further reduced in moisture by sunfinishing on plastic sheets in direct sun. These field treatments resulted in sixteen unique dried sultana bulk samples with a range of initial chemico-physical properties; aw (0.481-0.691), skin-polyphenoloxidase (PPO) activity (4.40-9.05 µmol O2/g.minute) free arginine in skin tissues (1.0-5.10 mg/g) and protein (16.40-27.18 mg/g). Sultanas were stored at 10°C and 30°C in either the presence or absence of oxygen for 10 months, and changes in CIE L*a*b* tristimulus values, hue-angle (hab*) and chroma (Cab*) were monitored. Significant changes in sultana colour occurred in samples stored at 30°C, especially in higher aw non-sunfinished sultanas. Although browning was more intense in the presence of oxygen, significant browning also occurred in the absence of oxygen. Lower concentrations of 5-hydroxy methylfurfural, a key marker of Maillard browning in samples stored at 30°C in the presence of oxygen, indicated that the non-enzymatic reactions were sensitive to oxygen. Changes in the concentration of trans-caftaric acid, the main substrate of grape PPO, were also measured during sultana drying. Storage browning (changes in L*, b*, hab*, Cab*)in dried sultanas could be predicted by regression models using pre-storage aw, free-skin arginine or Kjeldahl protein after 10 months' storage between 10°C and 30°C. Non-enzymatic and Maillard-type reactions (sensitive to both oxygen and aw), made an important contribution to sultana storage browning. We provide only weak evidence that either shaded (immature) or green fruit was more susceptible to storage browning.

Ten-year old Vitis Vinifera L. cv. Sultana (Thompson Seedless) grape vines were transferred into large cement pots in low nitrate soil and supplemented with four levels of nitrogen application in the form of ammonium nitrate as follows: O g (N0(, 8.5 g (N1(, 17.0 g (N2( and 25.0 g (N3(. Grapes were harvested from each nitrogen treatment, dipped and dried to low moisture (~1l.4%) and subsequently stored for 10 months at 10oC and at 30oC in either the presence or absence of oxygen. The pre-storage concentration of free arginine, free-proline and total protein in the dried sultanas increased with soil nitrogen application. Skin-pufyphenuluxidase (PPO( activity was higher in sultanas with added soil nitrogen (N1, N2, N3), however pre-storage differences in total phenolics, and the PPO substrate, truos-caftaric acid, were not significantly different. After 10 months storage al 300C significant browning was observed in both the presence and absence of oxygen. Greater browning corresponded to higher soil-nitrogen application rates. The concentration of skin irans-caftaric acid did not decrease in N0, N1 or N2 after 10 months at 30~C, in either the presence of absence of oxygen, although some decreases were measured in the highest nitrogen sultanas (N3(. While PPO oxidation of the phenolic substrate trans-caftaric acid was not the primary route to browning, a number of Maillard reaction product (MRP) were present in both sultanas and arginine-glucuse model systems. Those products were separated via reverse phase HPLC and partially characterised by UV-diode array spectroscopy. The lack of oxidation of trans-caftaric acid observed in the nitrogen storage trial was confirmed in an accelerated browning experiment in low-moisture sultanas, where despite browning at 50oC after 12 days. no decreases in this primary substrate by PPO-mediated oxidation were measured.

Browning during storage of low-moisture dried Vitis vinifera L. cv. Sultana (Thompson Seedless) grapes was examined in a multifactorial treatment and storage trial. Grapevines were subjected to two different levels of sun exposure, harvested fruit was dipped and subjected to different drying treatments to obtain a range of initial moisture contents (aw = 0.419-0.558). The storage effects of temperature (10°C and 30°C), and the presence of oxygen on colour change (CIE L*a*b* tristimulus values, hue-angle (hab*)) and chroma (Cab*) over a fourteen-month period were observed. The most significant changes in colour were measured for samples stored at 30°C, both aerobically and anaerobically, although the largest changes occurred in the presence of oxygen. Initial aw had a strong effect on colour changes; higher aw non-sunfinished samples underwent more significant browning compared to lower aw sunfinished controls regardless of their oxygen status. Changes in the concentration of the free-arginine and free-proline, the most abundant free amino acids in sultanas, were monitored throughout the storage period. Free arginine decreased significantly at 30°C in both the absence and presence of oxygen, whereas free proline increased (at both 10°C and 30°C), implying that free proline did not play a role in browning reactions at those temperatures. In addition to the decreases in free arginine, the concentration of 5-hydroxymethyl furfural (5-HMF), a marker of Maillard browning reactions, increased significantly in samples stored at 30°C. Significant differences in the concentrations of 5-HMF under the two oxygen conditions indicated sultana Maillard reactions, and possibly other non-enzymatic browning processes, were oxygen sensitive.

A number of white wines from vineyards outside the metropolitan region of Melbourne were analyzed for the trace metals copper, iron, potassium, sodium, magnesium and calcium by atomic absorption spectrometry (AAS). The 24 wines analyzed included Chardonnay, Sauvignon Blanc, Riesling, Gewurztraminer and Pinot Gris. In addition, preliminary transmission near infrared (NIR) spectrometric analyses for these metals in the above wines indicated, using both multiple linear regression (MLR) and partial least squares (PLS), that promising results may be obtained for some metals. The squared correlation coefficients ( R 2 ) and the ratios of the standard error of cross validation (SECV) and the standard deviation (S.D.) for the calibration models for potassium, sodium, magnesium and calcium were acceptable, however those for iron and copper were not. Although, only a small number of wines were used in this study, the preliminary data indicated that NIR spectrometry may provide a suitable, rapid method for analysis for some metals in white wines, and warrants a further investigation using a larger number of white wines over a wider range of locations.

An overview of the literature will be given of applications of Fame AA together with some references to Graphite Furnace AA to the analyses of foods such as: meat the main source of iron; dairy products, the source of calcium and fruit and vegetables for a range of metals. Comparisons will be given of metal content in these products particularly in meat and dairy products. Of the metals listed above, not all of these will be considered in every product: only where they are the metal of highest concentration. The aim of this chapter is to give a general comparison of the metal content in these products, which will not be exhaustive, particularly, with respect to fruit and vegetables but the ones most commonly consumed. The emphasis is on nutrition and to give the general reader and health professional a concise view of the metal content of these food products. From scientific aspect the methodology for Flame AA is relative straight forward, as is the work up for instrument presentation but there are often extra procedures that are required depending on the matrix that are essential for obtaining a valid result.