L. van Zyl

Using Fourier transform near infrared spectroscopy in determining kernel hardness, protein and moisture content of whole wheat flour

Fourier transform near infrared (FT-NIR) spectroscopy was used successfully to determine the kernel hardness, protein and moisture content of a single sample set of whole wheat flour. The hardness calibration was derived by performing partial least square (PLS) regression on baseline corrected data and using the particle size index (PSI) test as reference method. Both the protein and moisture calibrations were derived by performing PLS regression on multiplicative scatter corrected (MSC) and baseline corrected data. In all cases, the calibration models were subsequently tested by means of independent validation procedures. Good calibration and prediction results were obtained for all three characteristics. Standard error of prediction (SEP), root mean standard error of prediction (RMSEP) and correlation coefficient (r) values of 2.13%, 4.53% and 0.42, respectively, were obtained for the hardness calibration. Corresponding results for the protein and moisture calibrations were 0.51%, 1.16%, 0.81 and 0.15%, 0.38% and 0.85, respectively. The FT-NIR protein and moisture results of this study compare satisfactorily with results achieved in previous FT-NIR studies. No other FT-NIR wheat hardness results have been reported elsewhere, but results of this study compare well to those achieved in other NIR wheat hardness studies.

A taxonomic revision of Pelargonium section Campylia (Geraniaceae)

A multidisciplinary approach was followed in this revision of the section Campylia (Sweet) DC. In addition to macromorphology, the leaf anatomy, pollen morphology and chromosome numbers were studied to delimit the taxa and determine their relationships. Seven species and five subspecies are recognized. Two new subspecies, P. caespitosum Turcz. subsp. concavum Hugo and P. ovale (Burm. f.) L’Herit. subsp. hyalinum Hugo, are described. The status of P. ovale var. veronicifolium (Eckl. & Zeyh.) Hanv. is raised to subspecific rank as subsp. veronicifolium (Eckl. & Zeyh.) Hugo. It is concluded that the section Campylia is advanced and probably derived from the section Pelargonium DC.

Phylogenetic relationships, character evolution and biogeography of southern African members of Zygophyllum (Zygophyllaceae) based on three plastid regions.

The plastid coding rbcL and non-coding trnLF regions of 53 of 55 southern African Zygophyllum species were sequenced and used to evaluate the phylogenetic relationships within the southern African representatives of the genus. Published sequences of the same gene regions of Australian, Asian and North African Zygophyllum species were included to assess the relationships of the species from these regions to the southern African species. The addition of Z. stapffii from Namibia, found to be conspecific with Z. orbiculatum from Angola, lead to a greatly resolved tree. The molecular results were largely congruent with a recent sectional classification of the southern African species and supported their subdivision into subgenera Agrophyllum and Zygophyllum. Reconstruction of the character evolution of capsule dehiscence, seed attachment and seed mucilage showed that these characters allowed a division of southern African species into the two subgenera but that this could not be applied to species occurring elsewhere. Other morphological characters were found to vary and unique character combinations, rather than unique characters, were found to be of systematic value in sectional delimitation. The study suggests that repeated radiations from the horn of Africa to southern Africa and Asia and back lead to the present distribution of the taxa in the subfamily Zygophylloideae. Although this study supports some of the recent taxonomic changes in the group, the unresolved relationships between the proposed genera Tetraena and Roepera and those retained as Zygophyllum species suggest that changes to the taxonomy may have been premature.

Non-steroid anti-inflammatory drugs in asthma: dangerous or useful therapy?

The therapeutic potential of non‐steroid anti‐inflammatory drugs in clinical asthma is offset by the real possibility of hypersensitivity and inducton of severe airways obstruction. The influence of indomethacin on the antigen‐induced asthmatic response was tested. Early and delayed asthmatic responses were recorded after antigen challenge in 13 subjects. Indomethacin pretreatment totally or partially inhibited the delayed asthmatic response in 10 of 11 subjects. Inhibition by indomethacin of products of the arachidonic cascade which participate in the pathogenesis of the delayed asthmatic response could explain this phenomenon. A similar therapeutic response was documented without adverse drug reactions when five subjects were restudied after several months. In the same group the early asthmatic response was suppressed in six, enhanced in two and unchanged in four of 12 subjects. This variable response indicates that spasmogenic prostaglandin breakdown products may be important for certain individuals, but are generally of less importance in the early asthmatic response. Clinical trials with indomethacin as a steroid saving agent in allergic asthma appear feasible and can be conducted safely.

Using different sample holders in determining protein and moisture content in whole wheat flour by means of Fourier transform near infrared (FT-NIR) spectroscopy

Fourier transform near infrared (FT-NIR) spectroscopy was used to record the spectra of 92 whole wheat flour samples presented in three different sample holders. The conventional sample cup with a sapphire-glass base (provided with the spectrophotometer), borosilicate-glass vials and soda-glass vials were used. Calibrations were derived for protein and moisture content, respectively, of whole wheat flour by performing partial least square (PLS) regression on multiplicative scatter corrected (MSC) spectra and tested using independent validation procedures. Best results were obtained with the sample set analysed in the borosilicate-glass vials, although not significantly different (P > 0.05). The standard error of prediction (SEP), root mean standard error of prediction (RMSEP) and the correlation coefficient (r) were, respectively, 0.5%, 1.16% and 0.92 for the protein calibration model, and 0.15%, 0.38% and 0.94 for the moisture calibration model. The differences in spectral data due to the use of the different sample holders were investigated using correlation coefficients (r) and maximum distances (d). The significance of differences in prediction results was determined by performing an analysis of variance (ANOVA) on predicted protein and moisture values. Differences within each type of sample holder were also determined. All differences were found to be statistically insignificant (P > 0.05). The conventional sample cup can therefore be replaced by one of the more convenient vial types where each sample can be stored and presented to the spectrophotometer individually.

Deriving a grain hardness calibration for Southern and Western Cape ground wheat samples by means of the particle size index (PSI) method and Fourier transform near infrared (FT-NIR) spectroscopy

The bread wheat hardness scenario among the Southern and Western Cape cultivars was investigated by deriving a FT-NIR hardness calibration for 198 ground bread wheat samples and using the particle size index (PSI) test as referencê method. Particle size index results indicate that the investigated bread wheat cultivars have a very wide hardness range of 37.05 - 60.50%. The influence of genotype, location, protein content and moisture content on wheat hardness was investigated by means of ANOVA, Students t-test, correlation analysis and regression analysis. Significant differences (P < 0.05) in hardness were found for culitvars, while a positive linear relationship with protein content and a negative linear relationship with moisture content exist. The wheat samples were subsequently presented to the spectrophotometer in individual borosilicate-glass vials. A FT-NIR calibration was derived by performing a PLS regression on baseline-corrected spectra and the model was validated using an independent validation. Excellent results were achieved with an SEP, RMSEP and r of 2.13%, 4.53% and 0.89, respectively.