Astringency and other oral sensations : biological sources of individual variation and association with food and beverage behaviour

Orosensory perception strongly influences liking and consumption of foods and beverages. This thesis examines the influence of biological sources of individual variation on the perception of prototypical orosensory stimuli, food liking, self-reported alcohol liking and consumption, and indices of health. Two orosensory indices were examined: propylthiouracil (PROP) responsiveness, a genetically-mediated index of individual variation associated with enhanced responsiveness to orosensory stimuli often expressed as PROP taster status (PTS); and thermal taster status (TTS), a recently reported index of orosensory responsiveness. Taster status in PTS and/or TTS confers greater responsiveness to most orosensory stimuli. Gender, age, ethnicity, and fungiform papillae (FP) density were not associated with orosensory responsiveness to tastants, an astringent, and a flavour. Unlike PROP responsiveness, FP density was not associated with TTS. Both PROP responsiveness and TTS were associated with increased responsiveness to orosensory stimuli, including temperature and astringency. For PROP, this association did not hold when stimuli were presented at cold or warm temperatures, which are ecologically valid since most foods and beverages are not consumed at ambient temperature. Thermal tasters (TTs), who perceive 'phantom' taste sensations with lingual thermal stimulation, were more responsive to stimuli at both temperatures than thermal non-tasters (TnTs). While PTS, TIS, and gender affected self-reported liking and consumption of some alcoholic beverages, gender associated with the greatest number of beverage types and consumption parameters, with males generally liking and consuming alcoholic beverages more than females. Age and gender were the best predictors of alcoholic beverageAiking and consumption. As expected, .. liking of bitter and fatty foods and cream was inversely related to PROP responsiveness. TTS did not associate with body mass index or waist circumference, and contrary to previous studies, neither did PROP responsiveness. Taken together, TnTs' greater liking of cooked fruits and vegetables and high alcohol, and astringent alcoholic beverages than TTs suggests differences between TTS groups may be driven by perceived temperature and texture. Neither an interaction between PTS and TTS nor a TTS effect on PROP responsiveness was observed, suggesting these two indices of individual variation exert their influences on orosensory perception independently.

Magazine article - Ice Brawl: A New Beverage Prompts a battle

An article from The Economist, May 22nd, 2004, discussing the ice wine industry. The article focuses on those producing ice cider as a rival to ice wine. Mr. Ziraldo is quoted when discussing rules and regulations associated with ice wine. There is also a handwritten note on the article that reads: "D. Ziraldo Donald I am very impressed. Ian Davidson"

Metabolite changes during Riesling icewine fermentation when yeast micronutrients are used /

Icewine is an intensely s\veet dessert \vine fermented from the juice of naturally frozen grapes. Icewine fermentation poses many challenges such as failure to reach desired ethanol levels and production of high levels of volatile acidity in the fonn of acetic acid. This study investigated the impact of micronutrient addition (GO-FERM® and NATSTEP®) during the rehydration stage of the commercial \vine yeast Saccharomyces cerevisiae KI-VIII6 during Ice\vine fermentation. Sterile-filtered and unfiltered Riesling Ice\vine juice was inoculated \vith yeast rehydrated under four different conditions: in water only; with GO-FERM®; with NATSTEP®; or the combination of both micronutrient products in the rehydration water. Using sterile-filtered Icewine juice, yeast rehydration had a positive impact of reducing the rate of acetic acid produced as a function of sugar consumed, reducing the ratio of acetic acid/ethanol and reducing the ratio of acetic acid/glycerol. In the sterile-filtered fermentation, yeast rehydrated with micronutrients generated 9-times less acetic acid per gram of sugar in the first 48 hours compared to yeast rehydrated only \vith water and resulted in a 17% reduction in acetic acid in the final \vine \vhen normalized to sugar consumed. However, the sterile-filtered fermentations likely became stuck due to the overc1arification of the juice as evidenced from the low sugar consumption (117 gIL) that could not be completely overcome by the micronutrient treatments (144 gIL sugar consumed) to reach a target ethanol of IO%v/v. Contrary to \vhat \vas observed in the sterile-filtered treatements, using unfiltered Ice\vine juice, yeast micronutrient addition had no significant impact of reducing the rate of acetic acid produced as a function of sugar consumed, reducing the ratio of acetic acid/ethanol and reducing the ratio of acetic acid/glycerol. However, in the unfiltered fermentation, micronutrient addition during yeast rehydration caused a reduction in the acetic acid produced as a function of sugar consumed up to 150 giL sugar consumed.. In contrast to the sterile-filtered fermentations, the unfiltered fermentations did not become stuck as evidenced from the higher sugar consumption (l47-174g1L). The largest effects of micronutrient addition are evident in the first two days of both sterile and unfiltered fermentations.

Study of new yeast strains as novel starter cultures for Riesling icewine production

Icewine is a sweet dessert wine fermented from the juice of grapes naturally frozen on the vine. The production of Icewine faces many challenges such as sluggish fermentation, which often yields wines with low ethanol, and an accumulation of high concentration of volatile acidity, mainly in the form of acetic acid. This project investigated three new yeast strains as novel starter cultures for Icewine fermentation with particular emphasis on reducing acetic acid production: a naturally occurring strain of S. bayanus/S. pastorianus isolated from Icewine grapes, and two hybrids between S. cerevisiae and S. bayanus, AWRI 1571 and AWRI 1572. These strains were evaluated for sugar consumption patterns and metabolic production of ethanol, glycerol and acetic acid, and were compared to the performance of a standard commercial wine yeast KI-VI116. The ITS rONA region of the two A WRI crosses was also analyzed during fermentations to assess their genomic stability. Icewine fermentations were performed in sterile filtered juice, in the absence of indigenous microflora, and also in unfiltered juice in order to mirror commercial wine making practices. The hybrid A WRI 1572 was found to be a promising candidate as a novel starter culture for Icewine production. I t produced 10.3 % v/v of ethanol in sterile Riesling Icewine fermentations and 11.2 % v/v in the unfiltered ones within a reasonable fermentation time (39 days). Its acetic acid production per gram sugar consumed was approximately 30% lower in comparison with commercial wine yeast K I -V 1116 under both sterile filtered and unfiltered fermentations. The natural isolate S. bayanus/S. pastorianus and AWRI 1571 did not appear to be suitable for commercial Icewine production. They reached the target ethanol concentration of approximately 10 % v/v in 39 day fermentations and also produced less acetic acid as a function of both time and sugar consumed in sterile fermentations compared to KI-V1116. However, in unfiltered fermentations, both of them failed to produce the target concentration of ethanol and accumulated high concentration of acetic acid. Both A WRI crosses displayed higher loss of or reduced copies in ITS rDNA region from the S. bayanus parent compared to the S. cerevisiae parent; however, these genomic losses could not be related to the metabolic profile.

Characterisation and optimisation of the flavour of health-promoting, plantderived bitterants in functional beverages.

Flavour is a combination of taste, odour, and chemesthetic sensations. Close associations exist between these sensory modalities, and thus, the overall flavour of a food or beverage product can change when the intensity of one or more of these sensations is altered. Strategies to modify flavour are often utilized by the food industry, and are central to the engineering of new and reformulated products. For functional food and beverages, flavour modification is particularly important, as fortifying agents can elicit high levels of less than desirable sensations, such as bitterness and astringency. The application of various flavour modifying strategies can decrease the perceived intensity of these sensations, and in tum, improve the sensory profile of the product. This collection of studies describes the sensory characteristics of experimental functional beverages fortified with trans-resveratrol, (+)-catechin, and/or caffeine, and examines the impact of novel flavour modifying strategies on the perceived flavour of these beverages. In the first study, results demonstrate that the flavour profile of Cabemet Sauvignon wines fortified with 20 mglL and 200 mg/L of trans-resveratrol is not perceived as different compared to control wine (0 mglL). However, Riesling wine fortified with 200 mg/L is perceived as significantly higher in bitterness compared to 20 mglL and control. For some functional food formulations, alternative strategies for flavour modification are needed. Traditional methods, such as the addition of sucrose and sodium chloride, may decrease the perceived 'healthiness' of a product, and thus, may be sub-optimal. In a second study, high and low concentrations of five different bitter inhibiting compounds - 'bitter blockers' - (B-cyclodextrin, homoeridictyol sodium salt, carboxymethylcellulose - low viscosity, zinc sulfate, magnesium sulfate) were tested for their efficacy towards decreasing the bitterness of high and low concentrations of caffeine and (+)catechin - two health-relevant, plant-derived bitterants. B-cyclodextrin and homoeridictyol sodium salt were the most effective blockers at decreasing (+ )-catechin and caffeine, respectively. In addition to bitter blockers, additional flavour modifying strategies, either alone or in combination - may also be successful in functional food formulations. Both sucrose and rebaudioside A - a plant-derived sweetener - were effective at decreasing the bitterness of (+)catechin. When added to (+)-catechin along with B-cyc1odextrin, both sweeteners provided the most effective decrease in bitterness compared to binary, ternary, or quaternary mixtures of (+)catechin together with bitter blockers, sweeteners, andlor odourants. The perceived intensity of sensations elicited by sweeteners and odourants was not affected by the addition of bitter blockers, and thus, their impact within these complex matrices is minimal. In addition, withinmodal (taste-taste) compared to cross-modal (taste-odour) sensory interactions were more effective at decreasing the bitterness of (+ )-catechin. Overall, results from these studies demonstrate that certain novel, alternative flavour modifying approaches may be successful towards lowering the bitterness and astringency elicited by (+ )-catechin and caffeine in aqueous solutions.

Icewine fermentation by Saccharomyces cervisiae : fundamental stress responses and comparative fermentation dynamics

Please consult the paper edition of this thesis to read. It is available on the 5th Floor of the Library at Call Number: Z 9999.5 B63 P54 2007

Hyperosmotic Stress and the Impact on Metabolite Formation and Redox Balance in Saccharomyces cerevisiae and Saccharomyces bayanus strains

Wine produced using an appassimento-type process represents a new and exciting innovation for the Ontario wine industry. This process involves drying grapes that have already been picked from the vine, which increases the sugar content due to dehydration and induces a variety of changes both within and on the surface of the grapes. Increasing sugar contents in musts subject wine yeast to conditions of high osmolarity during alcoholic fermentations. Under these conditions, yeast growth can be inhibited, target alcohol levels may not be attained and metabolic by-products of the hyperosmotic stress response, including glycerol and acetic acid, may impact wine composition. The further metabolism of acetic acid to acetylCoA by yeast facilitates the synthesis of ethyl acetate, a volatile compound that can also impact wine quality if present in sufficiently high concentrations. The first objective of this project was to understand the effect of yeast strain and sugar concentration on fermentation kinetics and metabolite formation, notably acetic acid and ethyl acetate, during fermentation in appassimento-type must. Our working hypotheses were that (1) the natural isolate Saccharomyces bayanus would produce less acetic acid and ethyl acetate compared to Saccharomyces cerevisiae strain EC-1118 fermenting the high and low sugar juices; (2) the wine produced using the appassimento process would contain higher levels of acetic acid and lower levels of ethyl acetate compared to table wine; (3) and the strains would be similar in the kinetic behavior of their fermentation performances in the high sugar must. This study determined that the S. bayanus strain produced significantly less acetic acid and ethyl acetate in the appassimento wine and table wine fermentations. Differences in acetic acid and ethyl acetate production were also observed within strains fermenting the two sugar conditions. Acetic acid production was higher in table wine fermented by S. bayanus as no acetic acid was produced in appassimento-style wine, and 1.4-times higher in appassimento wine fermented by EC-1118 over that found in table wine. Ethyl acetate production was 27.6-times higher in table wine fermented by S. bayanus, and 5.2-times higher by EC-1118, compared to that in appassimento wine. Sugar utilization and ethanol production were comparable between strains as no significant differences were determined. The second objective of this project was to bring a method in-house for measuring the concentration of pyridine nucleotides, NAD+, NADP+, NADH and NADPH, in yeast cytosolic extract. Development of this method is of applicative interest for our lab group as it will enable the redox balance of the NAD+/ NADH and NADP+/ NADPH systems to be assessed during high sugar fermentations to determine their respective roles as metabolic triggers for acetic acid production. Two methods were evaluated in this study including a UV-endpoint method using a set of enzymatic assay protocols outlined in Bergmeyer (1974) and a colorimetric enzyme cycling method developed by Sigma-Aldrich® using commercial kits. The former was determined to be limited by its low sensitivity following application to yeast extract and subsequent coenzyme analyses, while the latter was shown to exhibit greater sensitivity. The results obtained from the kits indicated high linearity, accuracy and precision of the analytical method for measuring NADH and NADPH, and that it was sensitive enough to measure the low coenzyme concentrations present in yeast extract samples. NADtotal and NADPtotal concentrations were determined to be above the lower limit of quantification and within the range of the respective calibration curves, making this method suitable for our research purposes.

Influence of timing of milk consumption coupled with endurance training on body composition and endurance training adaptations in humans.

Consumption of low-fat milk (LFM) after resistance training has been shown to have positive influences on body composition and training adaptations; however, little research has examined the effects of LFM consumption following endurance training. The purpose of the study was to look at the effects of combining additional servings of LFM following endurance exercise on body composition, bone health, and training adaptations. 40 healthy males were recruited. Individuals were randomized into 4 groups – DEI (750mL LFM immediately post exercise), DEA (750mL LFM 4 hrs prior to or 6 hrs post exercise), CEI (750mL carbohydrate beverage immediately post-exercise), and CEA (750mL carbohydrate beverage immediately post-exercise). Participants took part in a 12-week endurance training intervention (1 h/day, 3 d/wk, ~60% max HR). 22 participants completed the study. Analysis showed significant increases in lean mass, spinal bone mineral content, relative VO2peak, and a decrease in Trap 5β across all groups (p < 0.05).

Letter - Premier Ernie Eves to Donald Ziraldo

A letter from Premier Ernie Eves to Donald Ziraldo, 13 September 2002. Premier Eves congratulates Mr. Ziraldo for recently receiving the Lifetime Achievement Award for Food and Beverage Excellence at the Sixth Annual New World of Food and Wine Festival.

General Price List, Ontario, 1 January 1924

A general price list from the year 1924 for the province of Ontario. The cover of the list reads: "Ontario Government Dispensaries Conducted Under Direction of Board of License Commissioners for Ontario By Authority of The Ontario Temperance Act. General Price List, Dispensaries sell liquor for medicinal, sacramental, scientific and manufacturing purposes only. The sale of liquor for beverage purposes in the Province of Ontario is prohibited by The Ontario Temperance Act. Dispensaries: No.1-154 Wellington Street West, Toronto; No.2-1271 Dundas Street West, Toronto; No.3-29 Charles Street, Hamilton; No.4-425 Talbot Street, London; No.5-30 Sandwich Street West, Windsor; No.6-Golden Lion Block, Kingston; No.7-92 Kent Street, Ottawa; No.8-109 Simpson Street, Fort William."