The research group began in 1997 when Marena Manley joined the staff in the Department of Food Science, and Stellenbosch University purchased its first near infrared (NIR) spectrophotometer. There are two main research focuses in this group: Cereal quality and NIR spectroscopy.

Fusarium fungi are detrimental to maize quality; early identification and increased understanding of Fusarium infection of maize kernels is needed. This project aims to develop a NIR hyperspectral imaging method for the identification of Fusarium infested kernels. Beyond this attempts will be made to observe Fusarium infiltration into maize kernels using x-ray and neutron scattering tomography.

Hectolitre mass (HLM) is the weight of a standard volume of grain and is often taken as an indication of bulk density. There is no internationally standardised device for measuring HLM. The use of different devices from around the world for the measurement of wheat HLM produced different values; however, these values were correlated between devices. The purpose of this project is to assess whether HLM measurements by different devices is problematic within the oats industry.

The RVA was first developed in 1985 by Newport Scientific for testing sprouting damage in wheat. Of particular interest is its capacity for monitoring cereal quality due to the presence of starch. Traditional analyses use specific points of the viscogram. Utilisation of the complete curve through the application of chemometrics to RVA data may enhance discrimination between cultivars differing in fermentability degree and is currently being investigated.

The hardness of maize is an important factor to consider before dry milling. Matrix-assisted laser desorption isonisation time-of-flight mass spectrometry (MALDI-TOF) and reverse phase high pressure liquid chromatography (RP-HPLC) are being used to investigate the zein protein profile of maize and perhaps provide some understanding of the basis behind hard endosperm texture.

Foam is a quality indicator of beer; superior beer foam is a balance of factors, e.g. protein, lipids, hops acids, metal ions, basic amino acids, ethanol, gas composition. Proteins such as LTP1 positively influence beer foam, however, increased LTP1 content inhibits yeast growth and vitality. Study of LTP1 in barley has largely been neglected due to the difficulty associated with its extraction. The purpose of this project is to ultimately produce a kit for LTP1 quantification which will allow greater process understanding when producing beer. This will require isolation of LTP1, the production of antibodies and the generation of standard curves relating LTP1 content to yeast inhibition and foam stability.

Low free amino nitrogen (FAN) has been implicated in the occurrence of problem fermentations while brewing. The influence of anti-microbial peptides has also been implicated in problem fermentations, however this is not as comprehensively understood as low FAN. The objective of this study is to establish the collective role of both yeast promoting and yeast inhibiting nitrogenous organic constituents in barley wort, and their effect on yeast performance during fermentation. It is also ultimately intended to develop a fermentability prediction model using HPLC, MS and NMR and multivariate data analysis

Breeding of new malting barley cultivars is a time-intensive, laborious and expensive process. It involves the evaluation of large numbers of samples; requiring a rapid, non-destructive analysis method to be applied to small sample sizes of early generation material. NIR spectroscopy is a technique with great potential for quality evaluation and would allow elimination of undesired cultivars in the early stages of breeding programmes. NIR spectroscopy calibration models are being calculated for a variety of agronomic (e.g. plumpness) and malting quality (e.g. diastatic power) parameters from whole and ground South African barley.

Pre-germination is a problem in small grain cereals. Pre-germination is the unwanted germination of mature grains with little or no visible indication; this leads to a reduction in crop yield, grain viability and functionality. Detection of pre-germination requires either destructive analyses or the subjective inspection of an experienced grader. NIR hyperspectral imaging is being investigated as an objective method of whole grain pre-germination detection.

Grain endosperm texture influences processing parameters; understanding and identifying endosperm texture is of general interest to the cereal industry. MALDI-TOF will be used to improve understanding the kafirin proteins in sorghum and perhaps how kafirins influence endosperm texture. Further, NIR spectroscopy will be used to extend on previous maize hardness investigations using NIR hyperspectral imaging.

Despite years of study the precise mechanism of bread staling is poorly understood. Here NIR hyperspectral imaging in conjunction with digital imaging and texture analysis will be used to further understand bread staling. In addition the effect of waxy wheat flour substitution, and therefore alteration of amylose - amylopectin ratios, on bread staling will also be investigated.

Spices are adulterated for economic gain or contaminated due to negligence. Up to 1547 metric tons in spice is traded annually, it is therefore important for consumer protection to detect the presence of adulterants in spices. This project is assessing the utility of NIR spectroscopy, particularly in the form of hyperspectral imaging, for the detection and quantification of millet and buckwheat flour adulteration of ground black pepper

A quick, simple, non-destructive method of species identification from raw whole meat samples is of interest to the meat industry. Here NIR spectroscopy is being trialled to differentiate between several types of game meat: springbuck; blesbuck; kudu; hartebeest; and gemsbuck.

In 2011 South Africa will host the 15th International Conference on Near Infrared Spectroscopy in Stellenbosch and Cape Town. Prof Marena Manley is the Conference chair. From now until the start of NIR 2011 there will be weekly Posts on the NIR 2011 blog – ‘IZiseko zeSayensi’. Topics will include Spectroscopy, Reference Methods, Instrumentation, Chemometircs and may more as part of the ‘back to basics’ approach we are taking. Numerous international researchers will contribute to the blog, which we expect will be particularly helpful to student delegates. For more information on NIR 2011 visit www.nir2011.org and subscribe to the Blog on www.nir2011.wordpress.com. NIR 2011 will be held under the auspices of the International Council for Near Infrared Spectroscopy (ICNIRS) (www.icnirs.org).

Jan Cilliers, Sensako, Bethlehem
Jan Cilliers of Sensako and Marena Manley are investigating conditioning of wheat for optimal extraction rate. Determination of extraction rates is dependent on the accurate determination of wheat hardness/viterousness as these measurements determine the amount of conditioning water used. This study will determine if a single kernel characterisation system is superior to the grain cutter method of hardness determination, and optimise conditioning method.

Prof Paul Geladi, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden
Marena Manley and Paul Geladi have been collaborating for the last three years. This collaboration has primarily focussed on the application of NIR hyperspectral imaging, and the multivariate analyses of the data obtained in such experiments. Paul Geladi is a professor in the Unit of Biomass Technology and Chemistry at the Swedish University of Agricultural Sciences and is a world expert in chemometric techniques.

Dr Glen Fox, Agri-Sciences, Toowoomba, Queensland, Australia
From 2008-2009 Dr Glen Fox was a post-doctoral fellow within the cereal quality and NIR spectroscopy laboratory, and continues to collaborate with the research group. Glen is the Principal Cereal Chemist with Department of Employment, Economic Development & Innovation, and leads research in cereal grain science as well as manages the Agri-Sciences Queensland – Grains Research Laboratory.

Prof Thomas Skov, Univeristy of Kopenhagen, Denmark
At the end of 2009 and the beginning of 2010 Thomas Skov spent 5 months sharing his time between the cereal quality and NIR spectroscopy laboratory and the Institute of Wine Biotechnology (IWBT). Thomas Skov is an assistant professor in the Quality & Technology group at the Department of Food Science, University of Copenhagen. During his time at Stellenbosch University Thomas Skov taught a course in basic chemometrics and assisted the analysis of a number of data sets.

Mette Holse, Univeristy of Kopenhagen, Denmark
Mette Holse was a member of the cereal quality and NIR spectroscopy laboratory during the same time as Thomas Skov. Mette Holse is a PhD student within the Quality and Technology group of the Department of Food Science, University of Copenhagen. While in the lab Mette completed a study using NIR hyperspectral imaging to observe chemical differences in various barley mutants.

Sanette van der Merwe, Vital Health, Brackenfell
Sanette van der Merwe is currently registered for her M-Tech Chemistry at the Cape Peninsula University of Technology under supervison of Mrs Merrill Wicht. Prof Marena Manley is her co-supervisor and the title of her project is: The application of near infrared (NIR) spectroscopy for the analysis of in-process and finished products during the encapsulation of semi-solid/liquid neutraceutical preparations. Neutraceuticals as the name suggests are the sum of nutrition and pharmaceuticals – food stuffs that provide health benefits. Methods are required for the monitoring and quality assessment of nutraceuticals; the purpose of this project is to determine the viability of NIR spectroscopy for the control of an encapsulation process.

Prof Trevor J Britz and Dr Gunnar O Sigge, Department of Food Science, SU
This collaboration is largely evidenced by Armelle Ntsame Affane’s PhD research – Monitoring of lactic acid production during Kefir mass-culturing. Kefir is a self-carbonated fermented milk product, the production of which is best monitored by following metabolite production. One such metabolite is lactic acid; NIR spectroscopy models have been calculated and are now routinely used within this research project. The success of Armelle’s work has lead to increased collaboration in the form of Harry Huang masters project – NIR and MIR spectroscopy for determination of COD, FOG and TSS in grain distillery waste water. In addition Prof Trevor Britz is co-supervising Paul William’s PhD (Food Science) project.

The Winter Cereal Trust currently provides bursaries and project funding for:

McGoverin C, Weeranatanaphan J, Downey G, Manley M. The application of near infrared spectroscopy to the measurement of bioactive compounds in food commodities. Journal of Near Infrared Spectroscopy 2010;18(2):87-111

Williams P, Manley M, Fox G, Geladi P. Indirect detection of Fusarium verticillioides in maize (Zea mays L.) kernels by near infrared hyperspectral imaging. Journal of Near Infrared Spectroscopy 2010;18(1):49-58.

Williams P, Geladi P, Fox G, Manley M. Maize kernel hardness classification by near infrared (NIR) hyperspectral imaging and multivariate data analysis. Analytica Chimica Acta 2009;653(2):121-130.

Manley M, Engelbrecht ML, Williams PC, Kidd M. Assessment of variance in the measurement of hectolitre mass of wheat, using equipment from different grain producing and exporting countries. Biosystems Engineering 2009;103(2):176-186.

Manley M, Williams P, Nilsson D, Geladi P. Near infrared hyperspectral imaging for the evaluation of endosperm texture in whole yellow maize (Zea maize L.) Kernels. Journal of Agricultural and Food Chemistry 2009;57(19):8761-8769.

Fox G, Manley M. Hardness methods for testing maize kernels. Journal of Agricultural and Food Chemistry 2009;57(13):5647-5657.

Affane ALN, Fox GP, Sigge GO, Manley M, Britz TJ. Quantitative analysis of DL-lactic acid and acetic acid in Kefir using near infrared reflectance spectroscopy. Journal of Near Infrared Spectroscopy 2009;17(5):255-264.

Geladi P, Manley M. Three-way data analysis of a wheat growing experiment using near infrared spectral data. Journal of Chemometrics 2008;22(3-4):247-251.

Manley M, Joubert E, Myburgh L, Lotz E, Kidd M. Prediction of soluble solids content and post-storage internal quality of Bulida apricots using near infrared spectroscopy. Journal of Near Infrared Spectroscopy 2007;15(3):179-188.

Manley M, Eberle K. Comparison of Fourier transform near infrared spectroscopy partial least square regression models for South African extra virgin olive oil using spectra collected on two spectrophotometers at different resolutions and path lengths. Journal of Near Infrared Spectroscopy 2006;14(2):111-126.

Manley M, Joubert E, Botha M. Quantification of the major phenolic compounds, soluble solid content and total antioxidant activity of green rooibos (Aspalathus linearis) by means of near infrared spectroscopy. Journal of Near Infrared Spectroscopy 2006;14(4):213-222.

Joubert E, Manley M, Botha M. Use of NIRS for quantification of mangiferin and hesperidin contents of dried green honeybush (Cyclopia genistoides) plant material. Journal of Agricultural and Food Chemistry 2006;54(15):5279-5283.

Baranska M, Schulz H, Joubert E, Manley M. In situ flavonoid analysis by FT-Raman spectroscopy: Identification, distribution, and quantification of aspalathin in green rooibos (Aspalathus linearis). Analytical Chemistry 2006;78(22):7716-7721.

Baranska M, Schulz H, Siuda R, Strehle MA, Rosch P, Popp J, et al. Quality control of Harpagophytum procumbens and its related phytopharmaceutical products by means of NIR-FT-Raman spectroscopy. Biopolymers 2005;77(1):1-8.

Nieuwoudt HH, Prior BA, Pretorius IS, Manley M, Bauer FF. Principal component analysis applied to Fourier transform infrared spectroscopy for the design of calibration sets for glycerol prediction models in wine and for the detection and classification of outlier samples. Journal of Agricultural and Food Chemistry 2004;52(12):3726-3735.

Geladi P, Manley M, Lestander T. Scatter plotting in multivariate data analysis. Journal of Chemometrics 2003;17(8-9):503-511.
Manley M, Van Zyl L, Osborne BG. Using Fourier transform near infrared spectroscopy in determining kernel hardness, protein and moisture content of whole wheat flour. Journal of Near Infrared Spectroscopy 2002;10(1):71-76.

Randall PG, Manley M, McGill AEJ, Taylor JRN. Relationship between the high M(R) subunits of glutenin of South-African wheats and end-use Quality. Journal of Cereal Science 1993;18(3):251-258.

Randall PG, Manley M, Meiring L, McGill AEJ. The high-molecular-weight glutenin subunits of South-African wheats. Journal of Cereal Science 1992;16(3):211-218.

Manley M, Randall PG, McGill AEJ. The prediction of dough properties of South-African wheat cultivars by SDS-page analysis of HMW glutenin subunits. Journal of Cereal Science 1992;15(1):39-47.