Hemicellulose is a valuable component of agro-food industrial wastes. Although there are some potential usage areas of hemicelluloses such as drug manufacture, encapsulation, and emulsification in food processing plants, they are not extensively utilized. In this study, effective extraction methods of the hemicelluloses from agro-food industrial wastes (corn peels and sugar beet pulp) and their application as coating material for banana fruits were investigated. Firstly, the effects of raw material type, particle size, and extraction conditions (alkaline concentration, temperature, time) and methods (direct alkaline extraction, alkaline extraction after component removal, and acidic extraction method) on hemicellulose yields were investigated. Sugar beet pulp and corn wastes were used as raw material. Alkali extraction resulted in 40.2% pure extracts while acidic hydrolysis gave only 27.4% purity in the same extraction conditions. The optimal extraction conditions were found as 30&deg / C temperature, 10% NaOH, and 24 h time (64.3%). It was also observed that removal of constituents such as fat, protein, starch, and soluble sugar increased the purity of hemicellulose from 40.2 to 58.2% at the same conditions. After finding optimum hemicellulose yield for practicle use, it was used as edible coating material to prevent darkening of banana fruits and any quality losses. On the fourth day of storage at 4 &ordm / C, there was no detected fungal decay of coated bananas / however, 20% of uncoated bananas (control) were infected. Moreover, the control group lost 5.1% of total weight but coated samples with 1%, 1.5%, and 2% hemicellulose (HC) lost 3.6%, 3.3%, and 3.1% of their total weight, respectively. Hemicellulose coating also protected firmness of bananas (701.1 gf for coated and 509.6 gf for uncoated samples at the end of 4th day). Color was another important quality parameter and it was showed that lightness and yellowness of coated bananas were preserved with very little losses at the end of storage period while control samples turned brown at an unacceptable level. The results indicated that using both low alkaline concentration and low temperature allows to recover higher quality extracts. In addition, hemicellulose showed a characteristic of a good edible coating material for banana in order to preserve their visual acceptance and other quality parameters.

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The effects of edible chitosan coating on quality factors of pomegranate (Punica granatum) arils were investigated in the present research. For that purpose, pomegranate arils were treated with 0% (control) and 1% chitosan (extracted from shrimp shells and deacetylated (.75%)) solutions and stored at 4

Alternative fuels are becoming important due to diminishing fossil fuel reserves and the environmental hazards associated with exhaust gases. Biodiesel is an attractive alternative fuel because it is environmentally friendly and can be synthesized from edible/non-edible oils. Though several methods are available for synthesis, transesterification is the preferred route for biodiesel synthesis. The current techniques for transesterification of the oils to biodiesel are based on acid/alkali catalysis. However, these methods do not work for oils with high free fatty acid content and also require an additional downstream step for separation of catalyst from the product. In this work, we investigate the synthesis of biodiesel by two techniques: in supercritical methanol and ethanol without any catalyst; in supercritical carbon dioxide using enzyme as catalyst. In the first technique, the transesterification of refined grade edible oil like sunflower oil, palm oil and groundnut oil, and crude non-edible oils like Pongamia pinnata and Jatropha curcas was investigated in supercritical methanol and ethanol without using any catalyst from 200 oC to 400 oC at 200 bar. The variables affecting the conversion during transesterification, such as molar ratio of alcohol to oil, temperature and time were investigated in supercritical methanol and ethanol. The conversion to biodiesel increased from 30-40% at a molar ratio of 10 to 80-85% at a molar ratio of 45 to 50. Very high conversions (96-97%) were obtained in supercritical methanol and ethanol within 30 minutes at 350 oC. The kinetics of the reaction was modeled, the rate coefficients and activation energies were determined. As an enzymatic transesterification in organic solvents is mass transfer limited, supercritical fluids are found to be a better alternative because of their gas like diffusivity. Among potentially interesting solvents for enzymatic synthesis, carbon dioxide is the most obvious choice in supercritical fluids, because it is non-toxic, nonflammable and easily available. Because the products and the enzyme do not dissolve in carbon dioxide at room conditions, separation can easily be achieved by reduction of pressure Thus, the enzymatic transesterification for production of biodiesel in supercritical fluids under mild conditions is of commercial interest. Therefore, biodiesel was synthesized using immobilized enzyme (Lipase, Novozym-435) in supercritical carbon dioxide. The effect of reaction variables like temperature, molar ratio, enzyme loading and kinetics of the reaction was investigated. The conversion to biodiesel was found to be lower in supercritical carbon dioxide than that in supercritical alcohol.

Thesis (M.B.A.)--University of Hong Kong, 1982.

M. Tech. Agriculture. / Aims of this study was to select a suitable modified atmosphere packaging that retained the overall quality and bioactive compounds of the traditional leafy vegetables during storage. In this study, three types of biorientated polypropylene packaging namely BOPP04, BOPP05 and BOPP06 with different perforations were tested on retention of quality parameters (weight loss, leaf yellowing, colour L*, C*, h&#x00BA%x;), decay, chlorophyll a, chlorophyll b, bioactive compounds (carotenoids, ascorbic acid, total phenolic compounds), antioxidant scavenging activity, and sensory properties at 10 &#x00BA%x;C at 2 day intervals up to 14 days.Films without perforation, with macro perforation and unpacked leaves were included for comparison.

New Fourier transform infrared (FTIR) approaches for the quantitative determination of peroxide value (PV) and isolated trans analyses were investigated and developed. The FTIR-PV methods investigated were all based on the stoichiometric reaction of hydroperoxides and triphenylphosphine (TPP) which converts TPP to triphenylphosphine oxide (TPPO). A reference transmission cell (100 mum) method was developed based on the use of a unique TPPO absorption at 542 cm-1. This method covered PV values from 0--15 PV and was shown to be superior in accuracy and reproducibility to the standard American Oil Chemists Society (AOCS) iodometric method. Subsequently, the utility of disposable polyethylene cards, normally used only for qualitative analyses, was investigated for quantitative PV determination. A quantitative IR card method was successfully developed and shown to serve as a very simple, rapid and alternative means of carrying out PV analyses. TPP-impregnated cards were able to reproduce the transmission cell PV results to +/-1.12 PV, while the unimpregnated card was slightly more accurate (+/-0.92 PV). A third FTIR-PV method was developed specifically for the at-line monitoring of high PV fatliquors and employed a germanium attenuated total reflectance sample handling accessory. This method hinged on the use of a TPPO absorption band at 1118 cm-1, normally off scale when pathlengths of >3 mum are used, but is suited to the analysis of oils having very high PVs (>250). The successful quantitative use of the disposable polyethylene IR card to PV led to its study for the quantitative FTIR determination of the isolated trans content of fats and oils and margarines. The polyethylene card was shown to unique and useful properties, tending to inhibit fat crystallization and its inability to retain moisture. These two properties allowed trans determination to be carried out on melted, high trans fats, without heating the polyethylene substrate and also to analyze margarines

Submitted in fulfillment for the Degree of Master of Technology (Biotechnology) in the Department of Biotechnology and Food Technology, Durban University of Technology, Durban, 2009. / Information regarding the nutritional value of wild food plants in Africa and current information varies from source to source. Prior to commercialization of wild foods the nutritional, ethnobotanical, medical, chemical, anthropological and toxicity requires investigation. Plants from the Amaranthaceae family were chosen because the family is characterized by several species which are used by indigenous communities as a source of nutrition in different plants of the world. The focus of this study was to investigate the nutritional and biological activities of three plants from the Amaranthaceae family viz. Achyranthes aspera, Alternanthera sessilis and Guilleminea densa that are considered famine plants. This study aimed to determine the nutritional value (proximate, minerals and vitamins), biological activity, toxicity and potential of a tissue culture system for three species from the family Amaranthaceae. Nutritional analysis comprised of determining moisture, ash, protein, fat, carbohydrate, dietary fibre and energy. Mineral analysis of calcium, copper, iron, magnesium, manganese, phosphorus, sodium and zinc was performed by microwave digestion and then analyzed by ICP Spectrophotometry. Vitamin A, Vitamin B1, Vitamin B2, Vitamin B3 and Vitamin C were also analyzed. For biological and safety analyses aqueous and methanolic extracts were prepared. Anti-oxidative and anti-inflammatory properties of the extracts were tested; antimicrobial activity was tested by evaluating the bactericidal, fungal effect and minimum inhibitory concentration on selected bacteria and fungi using the agar disk diffusion method. Anti mosquito potential was determined by setting up repellency, larvacidal assay and insecticidal assay. The safety and toxicity analysis was carried out by measuring cytotoxicity, toxicity and mutagenicity. The potential of an in vitro tissue culture system of A. aspera, A. sessilis and G. densa was determined using micropropagation. A. aspera indicated significant amounts moisture, ash, dietary fibre, protein, vitamin B1, vitamin B2, magnesium and manganese. Plant extracts of A. aspera had antibacterial activity against the Gram negative bacteria Esherichia coli, Pseudomas aeroginosa and Salmonella typhi; Gram positive bacteria Staphylococcus epidermis and Staphylococcus aureus. The methanolic extract had antifungal activity against Sacchromyces cerevisiae and exhibited significant free radical scavenging activity as well as 85% repellency against Anopheles arabiensis. The aqueous extract stimulated the growth of the K562 (Chronic Myclogenous Leukaemia) cell line and the plant extracts showed no mutagenicity or toxicity. A. sessilis indicated significant levels of ash, dietary fibre, protein, energy, vitamin A, vitamin B1, vitamin B2, vitamin B3, iron, magnesium and manganese present. Plant extracts of A. sessilis had antibacterial activity against Gram negative bacteria P. aeroginosa and Gram positive bacteria S. epidermis. The plant also showed antifungal activity against the yeasts S. cerevisiae and Candida albicans. The methanolic plant extract showed excellent antioxidant activity. The aqueous plant extract stimulated the growth of the K562 cell line and the plant extracts possessed no mutagenicity or toxicity. This plant grew well in a tissue culture system where it was propagated from callus to a fully grown plant able to survive in environmental conditions. G. densa has ash and dietary fibre, vitamin B2, vitamin B3 and iron. The plant extracts had antibacterial activity against Gram negative bacteria E. coli, P. aeroginosa and Klebsiella. oxytoca; Gram positive bacteria Baccilus stereathermophilus and S. aureus. The plant also has antifungal activity against C. albicans and significant repellency activity against A. arabiensis where it showed 100% repellency. This plant was not found to be mutagenic or toxic. The results obtained from this study show promising potential for the plants to be exploited as famine food plants. The nutritional value, biological activity and ability to micropropagate A. aspera, A. sessilis and G. densa indicates a good potential for purposes of harnessing biotechnological products.

Food insecurity can contribute to the advancement of diseases such as growth stunting and HIV/AIDS. A holistic approach to addressing food insecurity includes reviewing local resources; including indigenous food stuffs. Six studies investigate the potential of insect nutrition to meet dietary needs in rural South Africa. A novel trapping method for Trinervitermes sp. is examined by parameters of time, sustainability and bait used. Local grass (Themeda triandra Forssk.) seemed to be the most effective bait, being significantly more attractive than loose mound soil (p=0.01), wet maize stalks (p=0.01) or cardboard (p=0.05). The trapping device was demonstrated as an effective tool in assessing the feeding preferences of Trinervitermes sp., which compete directly with cattle for grazing food resources. The chemical composition of Macrotermes natalensis alates (winged, wingless and fried), soldiers, and Odontotermes sp. alates (wingless) was determined. Alates were rich in fat, ranging between 49.2-60.6% (dry matter basis). The protein content ofM natalensis and Odontotermes sp. alates compared favourably to pork and chicken. Alates were high in glutamic, aspartic and alanine amino acids and low in methionine, serine and threonine. Amino acid digestion for broiler chickens was high, ranging between 87.6-96.1%. In an era where rural and urban cultures are rapidly merging, entomophagy may be discarded as an embarrassment or nonsensical practice. The high nutritional content of M natalensis and Odontotermes sp. should be publicised both to increase the awareness of their high quality as a food source for both poultry and human consumption and to avoid the abandonment of cultural practices that make sense. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Aim: The prevalence of dental erosion is still increasing. A possible preventive approach might be rinsing with edible oils to improve the protective properties of the pellicle layer. This was tested in the present in situ study using safflower oil. Methods: Pellicle formation was carried out in situ on bovine enamel slabs fixed buccally to individual upper jaw splints (6 subjects). After 1 min of pellicle formation subjects rinsed with safflower oil for 10 min, subsequently the samples were exposed in the oral cavity for another 19 min. Enamel slabs without oral exposure and slabs exposed to the oral cavity for 30 min without any rinse served as controls. After pellicle formation in situ, slabs were incubated in HCl (pH 2; 2.3; 3) for 120 s, and kinetics of calcium and phosphate release were measured photometrically (arsenazo III, malachite green). Furthermore, the ultrastructure of the pellicles was evaluated by transmission electron microscopy (TEM). Results: Pellicle alone reduced erosive calcium and phosphate release significantly at all pH values. Pellicle modification by safflower oil resulted in an enhanced calcium loss at all pH values and caused an enhanced phosphate loss at pH 2.3. TEM indicated scattered accumulation of lipid micelles and irregular vesicle-like structures attached to the oil-treated pellicle layer. Acid etching affected the ultrastructure of the pellicle irrespective of oil rinsing. Conclusion: The protective properties of the pellicle layer against extensive erosive attacks are limited and mainly determined by pH. The protective effects are modified and reduced by rinses with safflower oil. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.