A previous study showed that addition of β-cyclodextrin to goat milk made a difference to its flavour, but in an undescribed way. Cyclodextrins (CDs, comprising α- β- and γ-CD) may be able to bind the free branched chain fatty acids in goat milk responsible for the largely undesirable ‘goaty’ flavour. The primary aim was to test the effect of CDs on this flavour in goat milk and its products with a view to marketing goat milk products with reduced flavour intensity. A secondary aim was to test the effect of β-CD on skatole flavour, a characteristic flavour of milk from pasturefed ruminants. Study design and methods: The present study evaluates addition of mainly β-CD to goat milk, cow milk and their products to reduce undesirable flavours. The methods applied were mainly ranking and hedonic assessment in sensory experiments. The tests done were with CDs added to buffers and milks, some of which were flavour-enhanced with 4-methyloctanoic acid as a representative goaty fatty acid, or with skatole. Goat milk yoghurts were also tested. Free fatty acid concentrations, which may be affected by CD binding, were measured after separating cream and skim milk. The methods applied were standard dairy procedures: titration of free fatty acids in milk fat and the copper-salt method for measuring fatty acids in skim milk. A fungal lipase was added to milks to accelerate fat hydrolysis (lipolysis). This was done to increase the concentration of free fatty acids for several experimental purposes. Some minor experiments studies were also done, for example the comparative effect of lipases on goat milk and cow milk, and the lipolytic activity at different temperatures over different times. Results: The results of skatole experiments were inconclusive. The odour of 4-methyloctanoic acid was reduced in acidic buffers by addition of α- and β-CD, particularly the former. Alpha and β-CD were both effective in goaty flavour reduction in goat milk. γ-CD was not effective. In all this work differences were statistically significant to varying levels. Goaty flavour was reduced by addition of β-CD to goat milk yoghurt, but only when added before fermentation (P < 0.001), not after (P = 0.09). The liking scores for goat milk yoghurts for both plain and flavoured yoghurts increased with β-CD treatment (both P < 0.001 for 59 panellists). The chemistry experiments revealed a reduction of free fatty acid concentration in the fat phase when β-CD treatment was added to full cream cow milk. However, analysis of skim milk did not show a corresponding increase in concentration. Further experiments are required to reveal the fate of the ‘missing’ fatty acids. Conclusion: Overall it was shown that under certain conditions, CDs were effective in reducing goaty flavour in milk and yoghurts. Whereas CDs are approved for addition to foods in many countries – including the bellwether U.S.A. – formal approval by Food Standards Australia New Zealand has not yet been finalized. When it is, the way should be clear to market a range of more consumer-acceptable goat milk products in New Zealand as a primary market. In short, this research has significant commercial relevance.

There is much interest in the nature and quality of the diet consumed by adolescents. To determine whether there are significant associations between diet and gain in height and weight in this age group, the present study analysed data on food intake and weight and height obtained on three occasions over a 30-month period from a total of 326 adolescents aged between 12 and 15 years. Information on sociodemographic and other lifestyle factors, including an indicator of physical activity, was also obtained. Energy intake was found to be a significant positive predictor of both height and weight gain. In addition intake of fat, calcium and riboflavin were found to be significant positive predicators of height gain and intake of carbohydrate and starch significant positive predictors of weight gain. After controlling for energy intake only riboflavin approached significance as a positive predictor of height gain. A food group analysis identified intake of dairy foods as a significant predictor of height gain. Although statistically significant the dietary predictors explained only a small proportion of the variability in height and weight (≤3.5%). Given the difficulties in obtaining complete dietary records from this age group and the generally adequate nature of the diet in the study group, the small proportion of height and weight gain explained by diet is not unexpected. Nevertheless the nutrient predictors identified are consistent with nutrient requirements for growth during adolescence and highlight the importance, for this age group, of an adequate intake of nutrients specifically provided by dairy foods. Few significant associations were found between growth rates and the sociodemographic and the lifestyle factors measured in this study. The ethnic diversity of the study sample may have contributed to this outcome.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

No description available.

The aim of this work is to collect, analyze and summarize information about prebiotics and probiotics using in producible dairy products in Lithuania, about features and quality of their consumption, production and labeling marking. Prebiotics and probiotics are mostly inserting into dairy products because it results their vitality. In process of this work was done written consumers quiz, sensual analysis of dairy products with prebiotics and probiotics, analysis of requests of labeling marking of those products according valid legislation. On purpose to find out if consumers have enough information about prebiotics and probiotics was preparing the questionnaire. During the poll it was aimed if consumers use products with prebiotics and probiotics. 50 Lithuanian residents were investigated. The data of the poll showed that consumers know about prebiotics and probiotics but not large amount of residents use those products. It is the reason of the deficit of information.-According valid legislation was done sensual analysis of yogurts: were evaluated sensual characteristics of yogurts and sensual descriptive- profiled analysis. Was formed the group of 5 estimators to valuate following characteristics: design, consistency, savour and smell. And was found out the average. During the sensual descriptive- profiled analysis consumers excluded 7 characteristics: sweetness, acidity, consistency, homogeneity, intensity of smell, intensity of savour, residual taste. The average of... [to full text]

Aim of study: to analyse the sensory analyses using to dairy products rating in Lithuania (law acts, assessors training, practical using in Lithuania). Tasks of study: to select and instruct assessors group to work by LST ISO 8586 – 1:1997. Sensory analysis. General guidance of the selection, training and monitoring of assessors. Part 1 : Selected assessors. To do descriptive analysis of dairy product (cheese) by LST ISO 4121:2004. Sensory analysis. Methodology. Evaluation of food products by method using scales. To make sensory profile of dairy product (cheese). Material and methods: the study’s was done at Food Safety and Animal Hygiene department in LVA and at Sensory Analysis Laboratory in KTU Food Institute. There were analysed 4 cheeses sensory analyses, done each of cheese comparable analysis and made profile. The assessors group were made from 7 students of LVA. This group selected in 2004 at KTU Food Institute and trained, but they didn’t have sensory analysis skills. At assessors screening was using these methods: ageusia, matching and ranking tests. At first assessors group was rating general cheeses appearance, odour and taste, consistency in 5 scoring. Then assessors group analysed the cheeses by earlier chosen and discussed attributes, used scales those attributes intensity to rate. From receive information were made sensory profile. To know consumers’ opinion about cheeses was used acceptability test. Results: the sensory analyses methods review showed, that... [to full text]

Over the years the demand for butter in Canada has decreased resulting in a surplus of butter. In 1965 the per capita consumption of butter in Canada was 8.23 Kg which decreased by about 70% to 2.66 Kg in 1994. Previous research indicates that consumers are switching from butter to margarine due to concerns about heart disease and high cholesterol levels in butter. Therefore, a market study was conducted in Montreal to estimate the potential demand for a new product called "modified" butter which would create 50% less cholesterol in the body than regular butter. When the concept of "modified" butter was introduced, out of 157 respondents about 80% of the respondents indicated that they would buy "modified" butter. Also, the total quantity of margarine demanded in a month decreased by 47% and the regular butter demand decreased by 85%. The market share of "modified" butter comes to about 67%. The average of the price that the consumers are willing to pay for a kilogram of "modified" butter is $7.50. A detailed cost analysis shows that the production cost of ``modified'' butter at the experimental level is high, but the average costs show a decreasing trend when the scale of production is increased. If the economies of scale were to continue along the derived cost curves, 7 tons of "modified" butter would have to be produced to reach the break-even point of $7.50/Kg cost of production. This shows the industrial potential of producing large quantities of ``modified'' butter by taking advantage of the economies of scale. Furthermore, the overall sales of butter (regular butter plus ``modified'' butter) would increase by about 25 % which would boost the consumption of butter in Canada.

Graduation date: 1993

No description available.

No description available.