Corn milling (co)products (n=120) were evaluated for their neutral detergent fiber residue (NDR) and neutral detergent insoluble protein (NDIP) ruminal degradation rates using several in vitro methods. Two (co)products (BPX-DDGS and HP-DDG) were fed to lactating dairy cows (n=44) to evaluate effects on milk production. The Cornell-Penn-Miner Institute (CPM) Dairy model was used to formulate diets and predict milk production. In vitro determined NDR and NDIP rates and were compared to CPM-dairy feed library values, and model predictions were compared with observed milk production. Additionally, BPX-DDGS and HP-DDG were defatted and compared with their intact forms for fermentation characteristics using the in vitro gas production (IVGP) technique. Fermentations were analyzed for rumen bacterial population shifts using the 16S rDNA bacterial tag encoded FLX amplicon pyrosequencing (bTEFAP) technique. Lastly, a novel ruminal in vitro method was described to measure the soluble protein fraction of feeds, with adjustments for microbial contamination. Fermentation rate of the NDR of BPX-DDGS and HP-DDG (0.08 and 0.07 h^-1, respectively) and NDIP degradation rates (0.07 and 0.06 h^-1, respectively) were similar to CPM-dairy feed library NDR and NDIP rates of corn distillers grain (0.07 and 0.05 h^-1, respectively). Model predictions using standard and in vitro determined values did not differ. As BPX-DDGS decreased and HP-DDG increased in the diet, observed milk production tended to decrease linearly (P = 0.08). There was a cubic effect for milk fat percent (P = 0.03) and a cubic trend for milk fat yield (P = 0.09). Milk protein yield also tended to decrease linearly (P = 0.06). CPM-dairy model prediction accuracies were less than 50 percent. Defatting (co)products reduced lag time and fractional rate of fermentation by at least half for BPX-DDG, and had no effect on HP-DDG. Defatting both (co)products increased the fibrolytic (26.8 to 38.7 percent) and proteolytic (26.1 to 37.2 percent) bacterial guild populations and decreased the lactate-utilizing bacterial guild (3.06 to 1.44 percent). The novel ruminal in vitro method determined that the specific activity of ammonia production was not different among (co)products. However, results were within numerical range of previously used methodologies.

Thesis (Masters Diploma (Food Technology))--Cape Technikon, Cape Town,1993 / This study is based on the Hazard Analysis in the Wet Milling of maize for the production of starch at the Bellville plant of African Products. Wet milling of maize is a highly specific and completely integrated system developed to separate the major components of the kernel as completely as possible. Many microbiological problems existed in the process at this plant which could not be solved over the years. Microbial analyses were done throughout the plant and high microbial counts were obtained at various sampling points. In applying HACCP, the following major hazards were identified: The presence of Faecal Streptococci, Sraphylococcus aureus, Bacillus cereus, Faecal coliforms, Fusarium, Dip/odia, Aspergillus, Penicillium and various Yeast strains. The follOWing Critical Control Points (CCP's) were identified in the wet milling process: Maize trucks, in-process water, steeping, storage tanks, Reineveld, wet mlxmg boxes, Laidlaw, drying and bagging off point. The follOWing were done as part of the HACCP plan: i) modifications of the plant were suggested, ii) different sanitation programmes were evaluated, iii) monitoring of cep's, and iv) training of personnel. In general, a regular sanitation programme need to be exercised in the wet-milling plant to prevent a build up of microbial populations at various sampling points. High S02 levels can be maintained throughout the plant to achieve this. The final starch will then be used for Industrial starch. Criteria to monitor the CCP's were suggested. Hazard Analysis is an effective method to improve the quality of the final product.

A rapid non-destructive Image Analysis (IA) technique was developed for the determination of maize kernel endosperm vitreousness. Kernels were analysed using a Leica Q-Win Q500 IW-DX Image Analyser fitted with Leica Q-Win software and connected to a Sony XC-75 CCD camera. Kernel translucency measurements were optimised by using a light system that involved positioning whole kernels on top of a mask containing round illuminated areas (circles), smaller than the projected areas of the kernels, allowing light to shine through the kernels only. Correction factors allowing for constant illumination of kernels were developed to adjust for kernel size variation in relation to constant light area. Similarly, a correction factor for the effect of kernel thickness on detected translucency values were developed. Significant correlations were found between corrected translucency values and vitreous and opaque endosperm yields as determined by hand dissection. These were: translucency as a percentage of the whole kernel and vitreous endosperm (mass%) (Translucency 1), r = 0.77, p<0.00001, and Translucency 1 and opaque endosperm (mass%), r = -0.72, p<0.00001 for white maize. Similar correlations were found for translucency as a percentage of endosperm (Translucency 2). Correlation coefficients increased significantly after kernel thickness corrections. Significant negative correlations were also found between corrected translucency values and Floating Number. For yellow maize, Translucency 1 correlation coefficients was r = 0.78, p<0.00001 and r = -0.71, p<0.00001 respectively with similar correlations for Translucency 2. Correlations were obtained after applying both correction factors for exposure and thickness. The IA technique was evaluated for predicting the yield of vitreous endosperm products during dry maiz~ milling in laboratory and industrial-scale milling trials. Significant positive correlations were found between corrected translucency values and yields of milling products from vitreous endosperm. Experiments using a laboratory-scale experimental roller milling test without a degerming stage produced the following correlations: between Translucency 1 and semolina yield (mass%), 0.74, p<0.001 and Translucency 2 and semolina yield (mass%), 0.70, p<0.001. For industrial-scale milling, a Bühler industrial-scale maize mill (3 tons per hour) was used. The correlation between Translucency 1 and extraction at degermer (degermer overtail yield) was 0.93, p<0.0001. There was a similar correlation for Translucency 2. Yellow maize was degermed using a pilot-scale Beall-type degermer and the correlation between Translucency 1 and flaking grits> 3.9 mm was 0.67, p< 0.001. The IA technique permits the non-destructive analysis of maize endosperm translucency on large samples of single kernels. It is suitable for rapid quantification of maize endosperm contents and predicting dry maize milling performance, as kernel translucency was significantly correlated with vitreousness in all instances. With further development of specific hardware and software, the technique has potential as an on¬line maize kernel classification system in industrial mills. As the method is non¬destructive, it is also suitable for classification of maize seed breeding material. It is also a potential method for the measurement of maize opacity as used by the wet milling industry, where opacity (the opposite of vitreousness) is related to maize starch yield. / Thesis (PhD(Food Science))--University of Pretoria, 2006. / Food Science / unrestricted

Call number: LD2668 .T4 1985 S364 / Master of Science

The problem of this investigation was to develop a satisfactory method by which insect infested corn could be treated continuously to eliminate the contamination normally found in the corn meal produced from the corn. An extensive literature review was compiled covering the processing of corn, the description of insects infesting stored corn, the sources of insect contamination, the tests for contamination in the corn meal, and the methods now employed or proposed for the reduction of this contamination. In connection with the fumigation of stored grain, tables were prepared showing the results of fumigations of grain insects with more than 400 chemical compounds. Those compounds which appeared to be best suited for this type of treatment of the corn, were then listed in a separate table and the properties of the compounds detailed so that a selection of the optimum compounds for experimental testing could be made. In addition to fumigation procedures, thermal procedures employing infrared radiation and dielectric heating were possible methods for killing the insects in the corn. Another procedure recommended for this purpose was the use of the mechanical force to kill the insect by means of high speed centrifugal machines called "Entoleter" Infestation Destroyers. By means of fragment analyses of samples of corn meal, it was found that the source of the corn and the care which it received during storage and handling were of primary importance in producing corn meal free from contamination by the present milling procedures. As a result of similar analyses it was found that precracking and aspirating of the corn on certain types of equipment prior to the normal grinding of the meal did not result in a reduction in the quantity of fragments present in the meal. Carbon tetrachloride and trichloroethylene were selected for possible utilization in very rapid fumigation of the infested corn. Laboratory apparatus based on the operation of the solvent-vapor degreaser for metal parts was constructed. In the resulting tests, it was found that with infested corn suspended in the vapor of boiling carbon tetrachloride or trichloroethylene the mortality of all stages of the rise weevil was 100 per cent after an exposure period of only one minute. Other tests indicated that after air drying of the grain the carbon tetrachloride did not have any deleterious effect on the baking properties of the corn. In connection with heat sterilization methods, tests were conducted which indicated that the baking properties of corn heated to temperatures below 160 °F were not impaired. Further tests were conducted which indicated that both infrared heating and dielectric heating were 100 per cent effective in killing all stages of rice weevil in infested com after an exposure period of two minutes to infrared radiation or one minute to dielectric heating. In both cases the temperature of the com did not reach 160 °F. Tests conducted with the "Entoleter” centrifugal machine indicated that the damage to the whole grain com by the action of the machine was excessive and all of the rise weevil were not killed. After due consideration of the experimental results it was decided that the system of rapid fumigation of the infested corn was the most reasonable solution to the problem of killing the insect infestation in the corn, The equipment necessary for the proposed system can be assembled with a few modifications of solvent-vapor, metal-degreasing equipment and with a suitable solvent recovery system. It is anticipated that the removal of the dead insects, larvae, eggs, and pupae can be accomplished on commercial milling equipment now available if the insects are killed prior to the processing and the reinfestation of the product is not an important factor during the processing. / Master of Science

Die doel van hierdie studie is om `n omvattende prysbepalingsmodel te ontwikkel vir vinnige bewegende voedselsoorte, met spesifieke verwysing na die mieliemeelbedryf. Deur navorsing wat gedoen is het dit aan die lig gekom dat daar nie `n enkele model bestaan wat prysbepaling in totaal aanspreek nie. Die model wat in hierdie verhandeling ontwikkel is, sal kan dien as `n omvattende prysbepalingsmodel en ook diegene wat nie bekend is met die prysbepalingsproses nie, tot voordeel strek. Hoofstuk 2 bied `n literatuurstudie van die faktore of komponente wat tydens prysbepaling verantwoord moet word. Hoofstuk 3 bied `n empiriese oorsig van die prysbepalingsmetodes wat TWK meulens aangewend het om die pryse van hulle klaarprodukte te bepaal, en hoe `n prysbepalingsmodel aangewend is om die winsgewendheid van die meulens te verhoog. Hoofstuk 4 word gewy aan die ontwikkeling van `n omvattende prysbepalingsmodel wat deur die mieliemeulebedryf en ander vervaardigers van vinnig bewegende voedselsoorte aangewend kan word. Hoofstuk 5 verskaf `n samevatting en riglyne vir verdere navorsing. / Business Management / M.Com. (Business Management)

Die doel van hierdie studie is om `n omvattende prysbepalingsmodel te ontwikkel vir vinnige bewegende voedselsoorte, met spesifieke verwysing na die mieliemeelbedryf. Deur navorsing wat gedoen is het dit aan die lig gekom dat daar nie `n enkele model bestaan wat prysbepaling in totaal aanspreek nie. Die model wat in hierdie verhandeling ontwikkel is, sal kan dien as `n omvattende prysbepalingsmodel en ook diegene wat nie bekend is met die prysbepalingsproses nie, tot voordeel strek. Hoofstuk 2 bied `n literatuurstudie van die faktore of komponente wat tydens prysbepaling verantwoord moet word. Hoofstuk 3 bied `n empiriese oorsig van die prysbepalingsmetodes wat TWK meulens aangewend het om die pryse van hulle klaarprodukte te bepaal, en hoe `n prysbepalingsmodel aangewend is om die winsgewendheid van die meulens te verhoog. Hoofstuk 4 word gewy aan die ontwikkeling van `n omvattende prysbepalingsmodel wat deur die mieliemeulebedryf en ander vervaardigers van vinnig bewegende voedselsoorte aangewend kan word. Hoofstuk 5 verskaf `n samevatting en riglyne vir verdere navorsing. / Business Management / M.Com. (Business Management)