Green garden peas (Pisum sativum L.) are a popular vegetable used in meal preparation worldwide. Green peas are commonly available in their frozen form due to their short growing season. Green peas are easily susceptible to changes in the field, immediately after harvest, during processing and storage, and thereforerequire careful handling to maintain good quality. The acceptability of frozen green peas is greatly dependent on the sensory quality. Descriptive sensory profiles and physico-chemical properties of frozen green peas can be investigated and used to assess and explain product quality. Six brands of frozen green peas representing product sold for retail and caterer's markets were purchased and subjected to descriptive sensory evaluation, physico-chemical analyses and quality grading. Four batches with different best before dates were purchased for each brand. Quality grading was done using statutory standards and a selected company protocol. Dry matter content, alcohol insoluble solids content, starch content, °Brix, residual peroxidase activity, size sorting, hardness using texture analysis and colour measurements were carried out for physico-chemical analyses. Generally, retail class peas were of superior sensory quality to caterer's peas although one caterer's brand had quality traits that were more comparable with the retail brands than the other caterer's brands. Quality grading revealed that frozen green peas can be downgraded due to poor colour, presence of extraneous vegetable matter, presence of sandy grits and soil stains, poor flavour and poor texture. Downgrading of peas can be due to one reason or due to a combination of two or more poor quality characteristics. Good quality peas were described as sweeter, smaller, greener, more moist and more tender than the poorer quality peas usingdescriptive sensory evaluation. Good peas also had high °Brix content, more intense green colour, low starch, alcohol insoluble solids, dry matter contents and texture hardness measured. Quality grading revealed that flavour problems were the major cause for low graded samples. Sensory evaluation and the methods used for instrumental analyses however, showed more easily the variations in texture attributes than flavour attributes of peas. Poor flavour was probably caused by ineffective blanching, low soluble solids content which enhanced the perception of bitterness and the presence of acetone notes. Poorly coloured peas were also either underblanched or had low moisture contents. Mealiness and hardness in peas were explained by high starch, alcohol insoluble solids and dry matter contents. Instrumental texture analysis showed indications that the harder peas also had tougher skins in addition to harder cotyledons. Lower peas also displayed characteristics typical of delayed harvesting and post-processing temperature abuse such as dehydration and pale green/white colouration. The sensory quality of frozen green peas can be predicted from the physico-chemical methods of analysis used in this study. Some of the frozen peas on sale are below the acceptable standards of quality. To achieve good frozen pea quality it is important to put emphasis on maturity at harvest and post processing storage conditions (store at -18 °C or lower and avoidfluctuatingtemperatures). The use of a strict quality grading scheme has been shownto result in good quality frozen peas. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Food Science / unrestricted

Studies generally agree on the critical influence of physico-chemical characteristics of raw potatoes on the physico-chemical and sensory characteristics of potato chips. However, the actual magnitude of differences in sensory quality and consumer acceptance of potato chips as a result of differences in the physico-chemical characteristics of raw potatoes are scarcely reported in most studies. This research was conducted to determine the effect of different physico-chemical characteristics of potato samples on the sensory quality and acceptance of potato chips. The potato samples which represented typical variations in physico-chemical characteristics that a potato chip manufacturer experiences were sourced over a six month period. The samples comprised of four potato varieties (A, B, C, D) sourced from five regions (V, W, X, Y, Z). The samples were coded AV, BW1, BW2, CW, CX, DY, DW and DZ. BW1 and BW2 were of the same variety and grown in the same region but harvested at different time periods. The sourcing of potatoes and potato chips were done at the manufacturer’s processing line during regular production. The potatoes were analyzed for physico-chemical characteristics generally reported to influence potato chip sensory quality, i.e. specific gravity (solids contents), starch content and reducing sugars content. After processing, the physico-chemical characteristics i.e. moisture content, colour and oil content of the respective unflavoured potato chip samples were analysed. The sensory qualities of both unflavoured and flavoured (sour cream and onion) potato chips of the respective potato samples were also determined. There were significant differences (p<0.05) in the specific gravity/solids content of the potato samples. The specific gravity and solids content ranged from 1.073 to 1.098g/cm3 and 19.2 to 24.9% respectively. Reducing sugars were not detected in any of the potato samples at a minimum detection level of 0.05 %. The potato chip samples differed significantly (p<0.05) in moisture content, oil content and colour (a * and b* values, chroma, hue angle) with ranges of 1.2 to 1.9 % (moisture), 33.1 to 40.8 % d.b (oil content), 0.39 to 3.69 (a *), 15.88 to 21.26 (b*), 15.93 to 21.37 (chroma) and 79.92 to 88.96 o (hue angle). Descriptive sensory evaluation showed that 6 and 8 of the attributes identified in the unflavoured and flavoured potato chip samples, respectively, differed significantly (p<0.05). Consumer sensory evaluation indicated that there was no clear preference of one chip sample over the others despite of differences observed through descriptive sensory analysis and physico-chemical characteristics. All the chip samples were generally liked. To the manufacturer this research could be regarded as of a quality control nature since the potato chip samples used in this study were of chipping varieties actually used by the manufacturer. The value of this research to the chip manufacturer was the fact that despite of slight differences in the physico-chemical characteristics (specific gravity/solids content and starch content) of potato samples, potato chips of acceptable sensory quality to the consumers were produced. / Dissertation (MSc)--University of Pretoria, 2011. / Food Science / unrestricted

O presente estudo teve, como objetivo principal, a determinação da composição físico-química e nutricional de onze amostras de méis com própolis comercializados no Estado de São Paulo, de acordo com as metodologias analíticas da legislação brasileira vigente (Instrução Normativa nº11 de 20 de outubro de 2000), que segue os métodos preconizados pelos Codex Alimentarius Commission (CAC), 1990 e Association of Official Analytical Chemists (AOAC), 1990). Amostras de mel puro e de própolis foram usadas como referência. Os resultados mostraram que os mesmos métodos usados para o controle de qualidade do mel puro (umidade, HMF, açúcares redutores, sacarose aparente, cinzas, acidez livre, sólidos insolúveis em água) foram adequados para o controle de qualidade do mel com própolis, exceto pela analise de atividade diastásica, que precisou de uma adaptação metodológica. A análise de minerais demonstrou que essas amostras não são fontes de ferro, magnésio, zinco e cálcio. A própolis adicionada ao mel aumentou o seu valor energético comparado com o mel puro. Cinco das onze amostras analisadas não apresentaram, na sua rotulagem, os valores nutricionais como recomenda a legislação. É indicada a necessidade de uma fiscalização mais rigorosa, assim como uma legislação específica para o controle de qualidade destes produtos. / The present work has, as its main objective, to determine the physico-chemical and nutritional composition of commercial samples of propolis added to honey from São Paulo State. Eleven honey-propolis samples were analyzed, according to the methods established by the Brazilian Law (Instrução Normativa n.11 de 20 de outubro de 2000) which recommends the same methods established by Codex Alimentarius Commission (CAC) and the Association of Official Analytical Chemists (AOAC, 1990). The results showed that the same methods used for pure honey quality control (moisture, HMF, reducing sugars, apparent sucrose, ash, free acidity, insoluble solids in water) except for the diastase activity which had to be adapted, can also be used for the honey-propolis quality control. The mineral analyses results showed that the samples were not a good source for iron, magnesium, zinc and calcium. Honey has its energy value enhanced by the addition of propolis if compared with pure honey. As five of the eleven samples analyzed did not have the nutritional values information on the labels as it is mandatory by the Brazilian Legislation, a more rigorous inspection and even a specific law should be established for the quality control of those products.

Thesis (M. Sc. (Horticulture)) -- University of Limpopo, 2019 / The South African Avocado Industry is continuously expanding with ‘Hass’ cultivar occupying the largest land and therefore, the most exported cultivar. Expansion of the industry implies an increased demand for irrigation water. However, South Africa is a water scarce country characterised by low and erratic rainfall, where fruit production relies heavily on irrigation. The agricultural sector is under an obligation to reduce water use due to the increasing demand for water by other economic sectors. Therefore, it must find efficient water use techniques to save water and ensure water availability for other economic sectors. Partial root-zone drying (PRD) is an irrigation technique which may lead to 50% reduction in water use, half of the root system is kept wet while the other half is left dry to a predetermined level of soil water depletion, the dry and the moist sides are alternated at regular intervals. During storage and transportation of fresh produce, low temperature is a post-harvest tool used to maintain quality, especially when fruit are destined for long distant export markets. This study investigated the effect of PRD and low temperature storage on post-harvest quality parameters of ‘Hass’ avocado fruit. The experiment was laid as a factorial arranged in randomised complete block design (RCBD). The treatment factors for chilling injury, electrolyte leakage and vascular browning were 2 x irrigation regimes (Full Irrigation (FI) vs. PRD) and 2 x storage temperatures (2.0 and 5.5°C). However, treatment factors for fruit weight loss, respiration rate, fruit firmness, ripening percentage and fruit skin colour were 2 x irrigation regimes (Full Irrigation (FI) vs. PRD), 2 x storage temperatures (2.0 and 5.5°C) and 4 ripening days (0, 2, 4 and 6 days). Mature ‘Hass’ avocado fruit were harvested from PRD and fully irrigated trees and thereafter fruit of each treatment were stored at 2.0 and 5.5°C for 28 days. Each treatment consisted of 6 replicates, with an exception of electrolyte leakage, whereby the experiment was replicated 4 times. After 28 days’ storage at 2.0 and 5.5°C, fruit were ripened at 21°C. The effect of PRD and low temperature storage was determined by evaluating the following physico-chemical fruit parameters during ripening: external chilling injury, electrolyte leakage, fruit weight loss, respiration rate, firmness, fruit skin colour and vascular browning. During ripening, ‘Hass’ avocado fruit stored at 2.0°C showed significantly higher incidences of external chilling injury symptoms compared with xiii 5.5°C, irrespective of irrigation treatment. Furthermore, an interaction between irrigation treatment and low storage temperature had a significant (P<0.05) effect on cell membrane electrolyte leakage. All evaluated fruit showed similar weight loss, irrespective of irrigation and storage treatment. Irrigation, storage temperature and ripening days did not have effect on respiration during ripening. Fruit reached the respiratory climacteric peak on the same day (day 2). Furthermore, there was no significant interaction effect (P˃0.05) on fruit firmness. However, PRD treated fruit showed slightly low firmness when compared with control fruit. ‘Hass’ avocado fruit harvested from PRD and fully irrigated trees and stored at 5.5°C ripened quicker compared to fruit stored at 2.0°C. There was no significant interaction effect (P˃0.05) on fruit skin lightness (L), chroma (C), hue angle (h°) and fruit eye colour due to irrigation and cold storage treatment. In general, fruit showed skin colour change from emerald green to approximately 75% coloured. Furthermore, irrigation and storage temperature did not have effect on vascular browning, however, there incidence was high on fruit stored at 2.0°C when compared with 5.5°C. The results of this study indicated that ‘Hass’ avocado fruit stored at 2.0°C was negatively affected by low temperature storage and this cold storage temperature is not recommended. PRD reduced water use during irrigation, however, its effect on post-harvest quality of ‘Hass’ avocado fruit subjected to 5.5°C must be further investigated before recommended for export markets. / Agricultural Research Council-Tropical and Subtropical Crops (ARC-TSC) and Agricultural Sector Education Training Authority (AgriSeta)

La pollution atmosphérique, et plus particulièrement la pollution particulaire d’origine anthropique constitue l'un des facteurs de risque environnemental les plus importants impliqués dans l’augmentation croissante de la morbi-mortalité liée aux pathologies respiratoires et cardio-vasculaires. Au coeur du domaine qu’englobent les activités pyrotechniques, que ce soit dans le domaine professionnel, civil ou militaire, les fumigènes sont référencés comme producteur important de particules et jouent donc un rôle non négligeable dans l’augmentation de cette pollution particulaire, exposant leurs utilisateurs aux différents aérosols émis.L’objectif général de cette étude exploratoire a été d’apporter des connaissances sur les caractéristiques physico-chimiques ainsi que sur la toxicité pulmonaire in vitro de particules émises lors d’activités pyrotechniques, et plus précisément de particules issues d’armes de petit calibre et de fumigènes.La caractérisation physico-chimique a démontré les particules de tir possédaient une granulométrie assez grossière (entre 3 et 7,5 μm) et étaient composées majoritairement d’éléments métalliques ; contrairement aux particules de fumigène qui appartiendraient à la classe granulométrique des particules fines (< 0,95 μm) et qui seraient majoritairement composées de molécules organiques différentes selon le type de fumigène. L’évaluation de la toxicité a été réalisée par une approche in vitro en utilisant des cellules épithéliales alvéolaires humaines (A549) exposées aux particules de tir et de fumigènes. Une étude de mutagénicité a été conduite à partir d’extraits organiques des particules de fumigènes. Parmi les particules testées, les particules de tir et du fumigène 1 ont induit une cytotoxicité. Les particules de fumigène 1 ont également induit un stress oxydant (augmentation de l’expression de l’ARNm de HO-1), une initiation de la réponse inflammatoire (augmentation de l’expression de l’ARNm d’IL-6 et IL-8) et des effets mutagènes.Les résultats de cette étude comparative ont démontré que les particules issues d’armes de poing et de fumigènes avaient une granulométrie, une concentration atmosphérique ainsi qu’une composition chimique différentes ; caractéristiques physico-chimiques responsables d’effets mutagènes et cytotoxiques différents ainsi que d’altérations des propriétés oxydantes et inflammatoires intrinsèques. Cette étude a mis en évidence la nécessité d’évaluer la toxicité des particules issues d’activités pyrotechniques en développant des moyens expérimentaux adaptés, depuis la collecte des particules jusqu’à l’évaluation de leurs impacts sanitaires. / Air pollution, and particulary anthropogenic particulate matter, is one of the most important risk factors involved in the high rate of morbidity and mortality related to respiratory and cardiovascular diseases. In pyrotechnic field, be it professional, civil or military activities, smokes constitue an important particle producer playing a major role in particulate matter emmergence and thereby exposing users to the various emitted aerosols.The main purpose of this exploratory study was to provide knowledge on the physicochemical characteristics of particles emitted during pyrotechnic activities, more specifically particles from gunfire and smokes, and to assess their pulmonary toxicity in vitro.On the first hand, the physicochemical characterization demonstrates that firing particles had a rather coarse granulometry (3 to 7.5 μm) and were mainly composed of metallic elemets, despite smoke particles belong to the category of fine particles (< 0,95 μm) and are predominantly composed of different organic molecules according to the smoke type.On the other hand, in order to assess the pulmonary toxicity of particles, we exposed human alveolar epithelial cells (A549) in vitro to particles coming from either gunfire and to two of the four different smokes (smoke 1 and 4). The results of this study showed that some of these particles (gunfire and smoke 1 particles) induced a mutagenic effects from organic extracts, as well as cytotoxicity. Moreover, particles of smoke 1 were also able to give rise to an oxidative stress (increased HO-1 mRNA expression) and to initiate an important inflammatory response characterized by pro-inflammatory cytokine upregulation (increase in IL-6 and IL-8 mRNA expression).The results of this comparative study demonstrated that particles from gunfire and smoke have different particle sizes and chemical composition. These physicochemical characteristics are responsible for different mutagenic and cytotoxic effects as well as alterations of the intrinsic oxidizing and inflammatory properties. This study also made it possible to understand the different methods of toxicological evaluation of smoke particles.

Thesis (M.Sc. (Aquaculture)) -- University of Limpopo, 2022 / The aim of this study was to provide baseline limnology data that can be used in the management of small dams, Molepo Dam and Hout River Dam. Physico-chemical parameters were assessed to determine the water quality and the effect of water level fluctuations on water quality. Water temperature, pH, dissolved oxygen, turbidity, electrical conductivity, nitrate, total phosphorus, total nitrogen and chlorophyll-a were assessed during the dry season (May-Oct) and wet season (Nov-Apr). Physico chemical parameters showed seasonal variations with the exception of pH. The mean total phosphorus (1.06 and 0.98 mg/L), total nitrogen (1.27 and 1.56 mg/L) and chlorophyll-a (2.97 and 3.32 µg/L) were higher in the dry season than wet season in Molepo Dam and Hout River Dam respectively. Water level fluctuations had a significant effect on total nitrogen, total phosphorus and turbidity in Molepo Dam and total nitrogen in Hout River Dam. Plankton were used as indicators of water quality. Phytoplankton and zooplankton were sampled using nets of 71 µm and 132 µm mesh respectively and identified to genus and species at both Molepo Dam and Hout River Dam. Individual species, number per litre for phytoplankton groups that contributed significantly in terms of abundance were Microcystis aeruginosa and Oscillatoria sp. in both Molepo Dam and Hout River Dam during the dry season months. The Shannon-Wiener diversity index was high during the wet season in these small dams. The abundance of Cyanophyta was greatest during the dry season followed by Desmids in Molepo Dam and Hout River Dam. During the wet season, Bacillariophyta were not recorded for Hout River Dam. The highest composition for Chlorophyta (15.4%) in Molepo Dam was recorded during the wet season months. Phytoplankton abundance was highest in Molepo Dam as compared to Hout River Dam throughout the sampling period. Zooplankton was dominated by Cladocerans (Bosmina longirostris) in both small dams. This study showed that plankton can be used as indicators of water quality. Zooplankton communities were dominated by Bosmina longirostris which was present throughout the sampling period possibly indicating clear water in Molepo Dam and Hout River Dam. Copepoda were sub-dominant phyla mainly represented by Cycloid sp. which are also indicators of clean water. The study determined the abundance and composition of fish species and growth parameters of the most abundant fish species (Oreochromis mossambicus) in the two small dams. Scales were successfully used for the age determination of O. mossambicus. The rings on the scales were validated as being true annuli by marginal increment analysis which indicated that the distance between the last annuli and the scale edge was shortest in the wet season months in Molepo Dam and Hout River Dam. This is the time in which annulus formed. Annulus formation of O. mossambicus at these small dams coincided with the onset of increased water temperature and rainfall (increased water levels and increased water inflow into the dams) in this region. Furthermore, the growth performance index (ϕ) of male O. mossambicus was higher than that of female O. mossambicus in both Molepo Dam and Hout River Dam. The study provides the first record of limnology baseline data of Molepo Dam and Hout River Dam / National Research Foundation (NRF) and Department of Agriculture, Forestry and Fisheries (DAFF)

No description available.

The relationship between soil properties and micromorphological features was studied in six Alfisol and six Spodosol profiles from Southern Ontario. The total porosity of the soil material was largely related to the size, shape and conformation of the soil voids in thin sections, while the differential development of plasma fabric could be used to discern a sequence of degrees of weathering which was also expressed by various mineralogical and physico-chemical indices. The relative proportions of soil constituents in thin sections was successfully used to indicate the existing textural discontinuities in five of the profiles studied. The elementary structure of soil thin sections is considered the most important micromorphological feature in the investigation of the degree of B horizon development in both Alfisol and Spodosol profiles. / Thesis / Doctor of Philosophy (PhD)

Flaxseed (Linum usitatissimum L.) gum (FG) is a material with many potential food and non-food applications. Consistent performance is critical for FG utilization and this is possible through selection of genotype, characterization and optimization of constituents, and chemical modification. Physico-chemical and functional properties of FG aqueous solutions from six Canadian flaxseed cultivars were investigated. FG yield, carbohydrate composition, protein content, and zeta potential (ζ) varied among these cultivars. FG solution properties were also affected by temperature, solution pH, NaCl concentration, and sucrose concentration. Detailed studies were conducted on CDC Bethune FG (FGB) proteins that were separated by 2D-gel electrophoresis. Conlinin was identified as the major protein. Protease treatment decreased FGB solution emulsification properties suggesting that conlinin might enhance emulsification. Formation of BSA-FGB coacervates was monitored by turbidimetric analysis as a function of solution pH, biopolymer mixing ratio, NaCl and urea. Coacervates were stabilized primarily by attractive electrostatic forces and secondarily by hydrogen bonds. Further, anionic carboxymethyl ether moieties were introduced to FGB structure through ether forming reactions using monochloroacetic acid (MCA) to produce products with uniform properties. The highest degree of substitution (DS) was obtained at 70 °C, 7.0 M NaOH, and a molar ratio of MCA to FGB of 10:1 over 3 h. Carboxymethylated FGB (CMFG) exhibited both modified surface morphology and thermal behaviour. Solutions of CMFG demonstrated shear-thinning behaviour and apparent viscosity decreased with increased DS. A more liquid-like flow behaviour was observed for CMFG as DS increased. Findings here will introduce and expand FG applications in food or related fields with targeted performance.

Pharmaceutical solids tend to exist in different physical forms termed as polymorphs. Issues about pharmaceutical systems are mainly concerned with the active ingredient's physico-chemical stability and bioavailability. The main aim of this study is to investigate the non-bonded interactions in pharmaceutical solids that govern the physical pharmaceutics performance of such materials and through the use of structural techniques and correlation of these results with crystal structural database to establish the presence of physical motifs in selected systems. Structural motifs were identified by the use of single crystal and crystal packing analysis on diverse range of pharma-relevant materials including chalcones, cryptolepines, biguanides and xanthines. These selected systems were validated using functional group and molecular analysis and correlating them to the Cambridge Structural Database. Crystallization studies are done on these selected systems as well as exploiting those using synthetic analogues. A total of 51 crystal structures were investigated including 16 new structure determinations. Addition synthesis of new xanthines to investigate novel intermolecular patterns was also undertaken. The understanding and exploitation of intermolecular interactions involving hydrogen bonds and coordination complexation during packing can be used in the design and synthesis of solid state molecular structures with desired physical and chemical properties.