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1.
IN VIVO TIME ANALYSIS OF THE DYNAMICS OF QUALITY DEVELOPMENT IN RIPENING APPLE FRUIT
Nadja Sadar, 2013, doktorska disertacija

Opis: Colour and taste are important attributes of apple fruit quality that is generated during the fruit-growing period. Despite a plethora of studies dealing with this topic, the detailed information on how quality is generated is, however, still lacking. This is because traditionally, the obtained agro-morphological and biochemical data are analysed with empirical models using mean values of large samples, without taking the effects of biological variation into account, thus completely masking the spatio-temporal physiological mechanisms. To really understand quality, its generation during fruit growth needs to be monitored and modelled. When knowledge exists on the type and kinetics of the processes involved, the variation in properties can be described and taken into account by using so-called fundamental models, built on theoretical considerations. To understand the behaviour and the variation of colour and taste compounds, within or between individual fruits, and to assess their importance throughout the food supply chain, it is therefore important to understand the dynamics of these compounds during growth. The study consisted of (1) a preliminary experiment, aiming to determine the suitability of the semi-destructive biopsy sampling technique for in-vivo monitoring of certain metabolites during apple fruit development on a tree, (2) an experiment on spatial distribution, and (3) an experiment on temporal distribution of metabolites and colour in developing individual apple fruit. The experiment on spatial distribution was conducted to determine the effect of location on the accumulation of the individual quality components within apple fruit, and the parallel temporal experiment was conducted to monitor the dynamics and mechanisms of these components in apple fruit during on the tree development. Diameter and standard maturity indices of fruit flesh firmness, soluble solids content, starch degradation index, titratable acidity, and Streif maturity index were also determined, to obtain relations between individual quality components. Colour descriptors (L*, a* b*), individual sugars (fructose, sucrose, glucose), sorbitol, and individual organic acids (malic, citric, shikimic, fumaric) were monitored from 40 and 54 days before to 16 and 32 days after the optimum maturity for long term storage on individual apples of cv. ‘Gala’ and cv. ‘Pinova’. Data were analysed with classic empirical statistics as well as with non-linear indexed regression, based on process oriented models, which included biological variation between apples of the same batch. Frequently probelation and quantile regression were applied. The results of the preliminary experiment confirmed that the novel biopsy sampling technique is suitable for in-vivo monitoring of the spatio-temporal distribution of colour and individual taste components during on-tree apple fruit development. In the results from the experiment on spatial distribution, a sinusoidal distribution over locations at 70° above the fruit equator was observed for all the monitored quality components. Descriptor a* was highest at the blush, and b* and L* at the shaded side of the fruit. Citric acid preferentially accumulated at the shaded side of the fruit, whereas fructose in cv. ‘Gala’ tended to accumulate at the blush. Other metabolites were more or less equally distributed within fruit. The results of longitudinal monitoring reveal a sigmoidal increase of a*, an exponential increase of diameter and sugars, and an exponential decrease of organic acids over time. In both cultivars, large variations were observed between individual fruit for all the monitored quality components. When analysed with non-linear indexed regression, based on process-oriented models, and after the probelation combined with quantile regression, the explained parts of the majority of the monitored quality components were well above 90 %. The mechanism of colour development was the same for both cultivars. The biological shift factor for all metabolites and colour had roughly the same value within cultiv
Ključne besede: apple fruit, colour, models, organic acids, spatio-temporal monitoring, sugars
Objavljeno: 19.12.2013; Ogledov: 1684; Prenosov: 183
.pdf Celotno besedilo (3,87 MB)

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Multi attribute decision model for orchard renewal - case study in Bosnia and Herzegovina
Karmen Pažek, Črtomir Rozman, Ferhat Ćejvanović, Andreja Borec, Darja Majkovič, Vjekoslav Par, Jernej Turk, 2005, izvirni znanstveni članek

Opis: The fruit production in Bosnia and Herzegovina (BIH) is slowly returning to normality after Balkan wars. Due to favorable climatic and soil conditions it presents a clear business opportunity for family farms. The decision which fruit species/variety to grow is a complex decision and should be made on the basis of sound empirical analysis. This paper present a multi criteria model for planning and decision making methodology based on expert system DEX-i. In the first stage the technological and financial cost benefit analysis were conducted for each fruit production alternative. The results were further evaluated with expert system DEX-i considering all possible criteria influencing the fruit grower decision. In the case of a sample family farm the plum yielded with best multi criteria evaluation, followed by apple and pear, while sour cherry gave unsatifactory outcome.
Ključne besede: cost benefit analysis, fruit production, multi attribute decision modeling, expert system DEX-i
Objavljeno: 10.07.2015; Ogledov: 507; Prenosov: 12
URL Povezava na celotno besedilo

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A feasibility study of fruit brandy production
Jernej Turk, Črtomir Rozman, 2002, izvirni znanstveni članek

Opis: Fruit brandy production is considered as one of the very possibilities for home fruit processing. When considering to set up new farm business, the information regarding the economic feasibility o9f individual agricultural households should be obteinded by each farm entrepreneur. The simulation cost model for Slovene brandy production on the fruit farms is developed in this study. The break-even price and break-even yield were calculated for different kinds of fruit brandy. The sensitivity analysis was simultaneously conducted in order to determine the impact of different prices on the net financial result gained. The results show that home fruit brandy production could be economically feasible. The highest financial result was achived with plum brandy production, followed by pear brandy production and peach brandy production. Several aspects of tax legislation concerning the brandy production are also discussed here.
Ključne besede: fruit production, brandy, costs, simulation model
Objavljeno: 10.07.2015; Ogledov: 687; Prenosov: 19
URL Povezava na celotno besedilo

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Effect of drying parameters on physiochemical and sensory properties of fruit powders processed by PGSS-, vacuum- and spray-drying
Urban Feguš, Uroš Žigon, Marcus Petermann, Željko Knez, 2015, izvirni znanstveni članek

Opis: Aim of this experimental work was to investigate the possibility of producing fruit powders without employing drying aid and to investigate the effect of drying temperature on the final powder characteristics. Raw fruit materials (banana puree, strawberry puree and blueberry concentrate) were processed using three different drying techniques each opera- ting at different temperature conditions: vacuum-drying (–27–17 °C), spray-drying (130–160 °C) and PGSS-drying (112–152 °C). Moisture content, total colour difference, antioxidant activity and sensory characteristics of the proces- sed fruit powders were analysed. The results obtained from the experimental work indicate that investigated fruit pow- ders without or with minimal addition of maltodextrin can be produced. Additionally, it was observed that an increase in process temperature results in a higher loss of colour, reduced antioxidant activity and intensity of the flavour profile.
Ključne besede: particles from gas saturated solutions drying, vacuum-drying, spray-drying, sensory evaluation, fruit powders
Objavljeno: 18.08.2017; Ogledov: 257; Prenosov: 105
.pdf Celotno besedilo (249,24 KB)
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