In this thesis, the impact of the interactions between the hydrophilic emulsifiers and aroma compounds as well as emulsion microstructure including droplet size, droplet size distribution, emulsion stability and creaming on aroma release over water-in-oil-in-water (w/o/w) emulsions was investigated. Polyglycerol polyricinoleate (PGPR) was used as the only hydrophobic emulsifier to stabilise the internal water droplets in the primary water-in-oil (w/o) emulsion of the w/o/w emulsions throughout this research. Three hydrophilic emulsifiers investigated to stabilise the w/o droplets in w/o/w emulsions included a low molecular weight non-ionic surfactant, polyoxyethylene 20 sorbitan monolaurate (Tween 20), a chemically modified starch, octenyl succinic anhydride (OSA) starch and a protein, pea protein isolate (PPI), as the large molecular weight emulsifiers. The two emulsification methods of high shear mixing and stirred cell membrane emulsification were used. Controls of water and oil-in-water (o/w) emulsions were prepared with the formulation and process conditions as for the w/o/w emulsions. Emulsion microstructure was characterised in terms of droplet appearance, droplet size, droplet size distribution as well as emulsion stability over time. Both static and dynamic headspace analyses were carried out to investigate the aroma release behaviour over w/o/w emulsions. The results showed that w/o/w emulsions were a suitable vehicle for short time aroma entrapment, which was most successful for the hydrophilic aroma acetoin compared to the hydrophobic aromas acetyl pyridine and hexanal. This entrapment of the hydrophilic aroma resulted from the barrier of the oil phase in the w/o droplets to delay its diffusion or the PGPR micelles in the oil phase to entrap it in the polar inner core. The complex food emulsifiers OSA starch and PPI were for the first time successfully used in stirred cell membrane emulsification to produce similarly sized o/w and w/o/w emulsions. These were produced to eliminate the effect of droplet size in the study of aroma release. The release of aromas (i.e. diacetyl and 3-pentanone) was affected by the combination of the type of the hydrophilic emulsifier (Tween 20, OSA starch and PPI) and the type of the emulsion system (i.e. o/w and w/o/w emulsions) as well as the emulsion microstructure including droplet size, emulsion stability, interface thickness, creaming and diffusion of the internal water phase into the external water phase of w/o/w emulsions. The thinner interface laden by Tween 20 might lead to a quicker diffusion of the hydrophobic aroma 3-pentanone from the w/o droplets into w2. OSA starch interacted with the hydrophilic aroma diacetyl and 3-pentanone, and PPI interacted with 3-pentanone. These findings help to better understand the effect of the hydrophilic emulsifier and emulsion microstructure on aroma release and present a novel study to produce similarly sized emulsion droplets with complex food emulsifiers.

Dates are the fruit of the palm, which the Greeks call “Phoenix”, a word taken from the Phoenician language. Saudi Arabia is currently one of the largest dates producing countries in the world. There are several varieties of dates grown in Saudi Arabia. Date fruits contain compounds that are potentially bioactive, with many health benefits; for example, vitamin E, carotene (precursor for vitamin A) and phenolic compounds. Dates represent an excellent source of antioxidants due to their high concentrations of phenolic compounds as well as the presence of selenoproteins. Moreover, dates are also potentially a very good source of several minerals in fact; there are at least 15 minerals found in dates. The work presented in this thesis will determine the nutritional composition of nineteen varieties of dates sourced from four, environmentally diverse, regions in Saudi Arabia. These varieties were selected because of their popularity, economical price, as well as availability during the year. The results indicated that the range of moisture contents (10% - 30%) found within the four regions were quite similar. For levels of fat, protein and ash all varied significantly between varieties but were all very low. Carbohydrate content was variable between samples (70 - 80%). The results indicated that glucose and fructose concentrations in theses Saudi dates were generally similar and the present of sucrose being normally associated with a corresponding reduction in the level of glucose and fructose. Potassium was the major mineral found in all the varieties with concentrations as high as 1173.29 mg/100g. The mean values for phosphorus in the dates from the different regions were close to each other. The amount of selenium was generally very low in all varieties and some did not contain any selenium at all. It would appear that it is variety and not region of production that has the major impact on nutritional composition. Moreover, this research will also determine the antioxidant capacity and phenolic content of a sub-set of these varieties at four different stages of ripening. Results showed that the levels of phenolics, anthocyanin and antioxidant capacity all decreased throughout development in all the seven selected varieties. There were strong correlations between this antioxidant capacity and the total phenolic and anthocyanin levels suggesting that these are major contributors to this nutritional property of dates. A preliminary screen tentatively identified some phenolic compounds and indicates that there may be some compositional variation between date varieties.

There has been growing interest in research focused on understanding the breakdown properties of foods in the gastro-intestinal (GI) tract, with a view to better design food systems that can control digestion with additional beneficial physiological effects (e.g satiety) to help tackle the obesity epidemic. The objective of the work presented in this thesis was to design a novel food emulsion microstructure, based on a dairy food matrix, to control digestion (measured in vitro). To achieve this, initially, skimmed milk powder (SMP), and either low or high molecular weight guar gum (GG) were used to establish SMP-GG phase diagrams at 5oC and pH 6.5 to better understand the phase behaviours of these systems. As expected, the compatibility of the SMP-GG system was found to increase with decrease in molecular weight of the GG. Confocal laser scanning microscopy (CLSM) clearly showed that the microstructure was dependent upon starting composition which in turn determined the relative phase volume of the two phases. This phase separated microstructure of SMP-GG can be considered as a water-in- water (W/W) emulsion. Through the incorporation of oil into these systems with designed microstructures based on the phase diagram, it was possible to form model systems of SMP-GG-OIL, showing the lipid phase within the protein phase within the polysaccharide phase. This can be described as ‘Matryoshka Composites’ and therefore being viewed as ‘O/W/W’ emulsion when the starting aqueous phase is either polysaccharide continuous or bi-continuous. Although the addition of a low volume fraction of oil has indicated an influence on the thermodynamic equilibrium of the SMP-GG system, through chemical analysis and rheological measurement; the in vitro digestibility of such phase separated model systems of SMP-GG-OIL with different microstructures was investigated using a pH Stat method. The microstructures were shown to be able to control lipid digestion. For a selected tie-line, the lipolysis of protein continuous > bi-continuous > polysaccharide continuous system, at a certain level of oil addition. The mechanism involved in the lipolysis of the designed formulations/microstructures was dependent upon the protein, rather than GG, and was driven by the protein concentration. As a comparison, in the case of adding different amounts of oil, the lipolysis was found to decrease with increasing oil phase volume. Confocal laser scanning microscopy revealed structural changes that occurred to the emulsified lipid droplets as they passed through a model gastro-intestinal (GI). The effect of the addition of non-ionic surfactants (Tween 20) on lipolysis of 20% sunflower oil included in the SMP-GG system has also been studied via the pH Stat method, as commercial products often contain other surface active materials. The presence of Tween 20 increased lipolysis, although it resulted in the increased droplet size arising from emulsion destabilization due to the competitive adsorption of protein and Tween 20 at the O/W interface leading to depletion flocculation. Moreover, the ‘unexpected synergism’ between Tween 20 and protein in facilitating lipolysis was enhanced with increasing Tween 20 concentration, indicating partial displacement of proteins by Tween 20 at the interface. The droplet surface laden with both protein and Tween 20 appeared like the surface of a ‘Golf Ball’ surface, so a 3D ‘Golf Ball’-like interfacial displacement model has been proposed. In contrast, if complete displacement occurred, lipolysis in the presence of Tween 20 was not further increased nor was it decreased. In addition, the oil type and physical state of lipid demonstrated an influence on lipolysis, but this was mainly dependent upon the lipid compositions and their melting points. These findings suggest the potential applications for food product design in regulating satiety effects by triggering the Ileal brake mechanism, and may provide opportunities to control delivery of specific nutrients during digestion.

Estery and woody flavour notes are important characteristics of distilled spirit flavour. It has been reported for malt whisky that the estery character of mature whiskies typically declines relative to that of the new make spirit, even though the analytical concentrations of esters remain broadly constant. One potential explanation for this observation would be a sensory interaction between mature and estery characters. The work described in this thesis was designed to test this hypothesis and to further explore the nature of the congeners responsible for eliciting these characteristics across different spirit types, as influenced by their maturation conditions (time, temperature, cask provenance etc.). In the research described in Chapter 2, four pairs of non-mature and mature spirits (tequila, bourbon and 2 malt whiskies) were characterized by instrumental analysis with the aim of defining the key aroma compounds that determined the mature character in each spirit. According to PLS analysis of the full data set, concentrations of 17 congeners were positively correlated with ageing time and might thus influence the mature character of the aged spirits. In Chapter 3, the same eight spirit samples were analysed by GC-Olfactometry using the AEDA (aroma extraction dilution analysis) approach. Aged spirits presented a more complex aroma than new make spirits, and contained more compounds with the highest FD-factors. Whilst a full GC-O characterisation was completed, the main focus was on identifying compounds which contributed to the estery and woody/mature characters of each spirit. In Chapter 4 we attempted to reproduce these characters for each spirit through aroma recombination, based on blends of the odiferous compounds identified at high FD factors and their analytical concentrations in the actual samples as reported in Chapter 3. It soon became apparent that relatively simple mixtures of esters on the one hand and maturation-linked compounds on the other did not adequately reproduce the nature of these characteristics in the spirits themselves. This implied either that our analysis had missed some significant compounds contributing to these characteristics, or that the complexity of the full spirit matrix is required to give the groups of compounds the nuanced flavour that they lacked in isolation. The latter hypothesis was tested by adding in additional blends of compounds to increase the complexity of the recombinant aroma mixtures. It was concluded that the authenticity of the aroma blends overall was improved by both the addition of a cocktail of ‘low boiling compounds’ (those analysed by a separate direct injection GC technique) and the introduction of a ‘structuring’ compound (ethyl hexadecanoate) at a concentration that would cause agglomeration within the whisky (micellar structures) thus influencing aroma partitioning and release. It was concluded that these modifications produced recombinant aromas which were close enough to the authentic spirit characters to use them in sensory interaction studies (Chapter 5). As opposed to interaction effects there was simply a tendency for the woody/mature characters to suppress the corresponding estery character of mature spirits, particularly at the higher concentrations of added wood extractives. Because the woody/mature compounds which characterised maturation were broadly similar across the spirit types, but differed in concentration according to the maturation conditions, we decided finally to investigate the extraction kinetics of wood-derived compounds from oak sticks as a function of ageing time, temperature, spirit type and alcohol content (Chapter 6). Temperature and alcohol content were the most significant factors that determined the extraction rate and final concentrations of all 18 wood-extractive compounds (P < 0.05) analysed. Not surprisingly, extraction rates increased with increasing temperature, but the trend in terms of alcoholic strength depended on the particular compound. Overall this thesis has improved knoEstery and woody flavour notes are important characteristics of distilled spirit flavour. It has been reported for malt whisky that the estery character of mature whiskies typically declines relative to that of the new make spirit, even though the analytical concentrations of esters remain broadly constant. One potential explanation for this observation would be a sensory interaction between mature and estery characters. The work described in this thesis was designed to test this hypothesis and to further explore the nature of the congeners responsible for eliciting these characteristics across different spirit types, as influenced by their maturation conditions (time, temperature, cask provenance etc.). In the research described in Chapter 2, four pairs of non-mature and mature spirits (tequila, bourbon and 2 malt whiskies) were characterized by instrumental analysis with the aim of defining the key aroma compounds that determined the mature character in each spirit. According to PLS analysis of the full data set, concentrations of 17 congeners were positively correlated with ageing time and might thus influence the mature character of the aged spirits. In Chapter 3, the same eight spirit samples were analysed by GC-Olfactometry using the AEDA (aroma extraction dilution analysis) approach. Aged spirits presented a more complex aroma than new make spirits, and contained more compounds with the highest FD-factors. Whilst a full GC-O characterisation was completed, the main focus was on identifying compounds which contributed to the estery and woody/mature characters of each spirit. In Chapter 4 we attempted to reproduce these characters for each spirit through aroma recombination, based on blends of the odiferous compounds identified at high FD factors and their analytical concentrations in the actual samples as reported in Chapter 3. It soon became apparent that relatively simple mixtures of esters on the one hand and maturation-linked compounds on the other did not adequately reproduce the nature of these characteristics in the spirits themselves. This implied either that our analysis had missed some significant compounds contributing to these characteristics, or that the complexity of the full spirit matrix is required to give the groups of compounds the nuanced flavour that they lacked in isolation. The latter hypothesis was tested by adding in additional blends of compounds to increase the complexity of the recombinant aroma mixtures. It was concluded that the authenticity of the aroma blends overall was improved by both the addition of a cocktail of ‘low boiling compounds’ (those analysed by a separate direct injection GC technique) and the introduction of a ‘structuring’ compound (ethyl hexadecanoate) at a concentration that would cause agglomeration within the whisky (micellar structures) thus influencing aroma partitioning and release. It was concluded that these modifications produced recombinant aromas which were close enough to the authentic spirit characters to use them in sensory interaction studies (Chapter 5). As opposed to interaction effects there was simply a tendency for the woody/mature characters to suppress the corresponding estery character of mature spirits, particularly at the higher concentrations of added wood extractives. Because the woody/mature compounds which characterised maturation were broadly similar across the spirit types, but differed in concentration according to the maturation conditions, we decided finally to investigate the extraction kinetics of wood-derived compounds from oak sticks as a function of ageing time, temperature, spirit type and alcohol content (Chapter 6). Temperature and alcohol content were the most significant factors that determined the extraction rate and final concentrations of all 18 wood-extractive compounds (P < 0.05) analysed. Not surprisingly, extraction rates increased with increasing temperature, but the trend in terms of alcoholic strength depended on the particular compound. Overall this thesis has improved knowledge of the chemical and sensory changes that accompany spirit maturation and has highlighted some of the factors that cause differences in mature character across spirit types. / Moreover, it concludes that the sensory perception of woody/mature generally suppresses the fresh estery characteristic of new make spirits, even though analytically the esters are still there in similar concentrations. wledge of the chemical and sensory changes that accompany spirit maturation and has highlighted some of the factors that cause differences in mature character across spirit types. Moreover, it concludes that the sensory perception of woody/mature generally suppresses the fresh estery characteristic of new make spirits, even though analytically the esters are still there in similar concentrations.

Digitized by Kansas Correctional Industries

Based on the need for a food manual for the introductory food course at Western Kentucky University, several .manuals from other sources were reviewed. None was found which met the need. the Food Science course, so it was decided that a manual would be developed at Western. The purpose of the manual was to incorporate experiences which could meet the needs of any student taking the course either as an elective or as a program requirement. Since there is only one introductory course to serve all students who are interested in learning basic food preparation skills, such a manual was deemed a necessity by the faculty in the food area. The development of the manual became a Specialist Degree project for the author, who had been assigned the responsibility of teaching the introductory food course. This project report explains fully the procedures followed in developing the manual according to the unique conditions which prevail when one course must serve a body of students with widely diverse needs. Although the project was limited in scope to the development of the manual, it was recognized that such a teaching resource does not and should not remain static. In light of this a suggested procedure for continuous evaluation and revision was included, along with a tentative time table for the first evaluation cycle.

Source: Dissertation Abstracts International, Volume: 35-07, Section: B, page: 3429. / Thesis (Ph.D.)--The Florida State University, 1974.

Source: Dissertation Abstracts International, Volume: 39-03, Section: A, page: 1386. / Thesis (Ph.D.)--The Florida State University, 1978.

Source: Dissertation Abstracts International, Volume: 34-04, Section: B, page: 1618. / Thesis (Ph.D.)--The Florida State University, 1973.

Source: Dissertation Abstracts International, Volume: 34-06, Section: B, page: 2756. / Thesis (Ph.D.)--The Florida State University, 1973.