Hans J. Rosenfeld

The effect of temperature on sensory quality, chemical composition and growth of carrots (Daucus carota L.) I. Constant diurnal temperature

SummaryThe carrot cv. Panther FT grown in phytotrons at 9,12 15,18 and 21°C constant diurnal temperatures at two locations, As (59°40’N) and Tromso (69°39’N), and harvested at two dates was evaluated for sensory attributes, chemical composition and morphological variates. Significant temperature effects were detected for most sensory, chemical and physical variables. High growing temperatures (18 and 21°C) favoured colour, bitter tasting flavour components, firmness and the dry matter, sucrose and carotene content of the roots, whereas low growing temperature (9 and 12°C) heightened sweet taste, acidic taste, crispness, juiciness, and the fructose and glucose content. The longest roots were obtained at 9 and 12°C, the highest root weights at 12 and 15°C. Principal component analysis (PCA) revealed clear differences in the sensory profile of carrots grown at high and low temperatures, expressed by the first three principal components which together explained 81% of the variation in sensory variables. PCA o...

Evaluation of carrot varieties for production of deep-fried carrot chips — I. Chemical aspects

Abstract Carrot variety had a significant influence on the dry matter, redness ( a ∗ ) and sucrose content, while cultivation site (environmental condition) had a significant influence on the dry matter, lightness ( L ∗ ), redness ( a ∗ ), sucrose and glucose content. The chemical content of raw carrots could be used to predict the quality of carrot chips by means of three factors when partial least-squared analysis was applied. Factor 1 was explained by the difference in colour at the different cultivation sites, factor 2 by the difference in sucrose content in the different varieties, while factor 3 covered both colour and sugars, and grouped the cultivation sites in three where the carrots had similar chemical composition.

Evaluation of carrot varieties for production of deep fried carrot chips—III. Carotenoids

Abstract Carotene contents of four carrot (Daucus carota L.) varieties, grown at six latitudes in Norway, demonstrated that carrots grown at two locations far south had the highest carotene contents, while no effect of variety was seen. Carotene contents of carrot chips correlated significantly with those of raw carrots and averaged 88% of initial amount, about 20% being identified as 9-cis β-carotene. The carotenes corresponded to 4140 retinol equivalents (RE) per 100 g chips, demonstrating carrot chips as a good source of carotenes. For raw carrots, CIE (1976) L∗, a∗ and Hue° values correlated significantly with carotene content, while for chips, a∗, b∗ and Hue° values correlated with carotene content.

MAP of highbush blueberries: sensory quality in relation to storage temperature, film type and initial high oxygen atmosphere

Abstract Highbush blueberries ( Vaccinium corymbosum L. ‘Bluecrop’) were packed into two film types with different gas permeances and filled with a high-oxygen atmosphere (40% O 2 ) or normal air, and stored at 4 and 12°C. Sensory and chemical attributes were assessed, and the data were submitted to principal component analysis (PCA). The storage temperature was more important than film type and initial atmosphere modification. Important sensory variables for blueberries stored at low temperature were acidic taste and blueberry flavour. At a high storage temperature, bitter taste and storage flavour were the most important sensory variables to describe the samples. The film type was the second most important component, causing differences in the CO 2 content within the packages. Blueberries stored in film with high gas permeance gave the highest scores for sensory texture and blueberry flavour. Initial high oxygen atmosphere had only little influence on sensory quality.

Sensory profiling of carrots from northern latitudes

Abstract Carrot varieties grown in southern and northern Norway ranging from 58 ° 10′ N to 69 ° 39′N, a distance of 1200km, during two years were evaluated by means of sensory analyses. Principal Component Analysis (PCA) showed three factors explaining 73% the first year and the second year 82% of the total. Principal Component 1 could be interpreted as a temperature related factor grouping the samples related to their growth site along the direction north to south, with attributes describing colour and flavour intensity being characteristic for the southern locations, and juiciness, acidic taste, sweet taste and whiteness being characteristic for the northern latitudes. The genetic variation, mainly related to the variation in sugar and texture related attributes, was explained at a rate of 14–16% by PC 2 and 9–10% by PC 3. Characteristic northern and southern profiles could be drawn on the basis of 17 sensory attributes as evaluated by a trained sensory panel.

The effect of temperature on sensory quality, chemical composition and growth of carrots (Daucus carota L.). IL Constant diurnal temperatures under different seasonal light regimes

SummaryCarrots of cv. Panther F1 were grown in climate chambers at 9, 12, 15, 18 and 21°C, constant diurnal temperatures at three different periods of the year. The effect of varying solar radiation and temperatures were evaluated on growth, sensory attributes and chemical composition. Higher levels of light significantly increased most chemical and physical variables of the carrot roots. Temperature was the most important factor determining the variation in sensory and chemical variables, whereas for morphological features like root weight, root length and diameter measurements, light was more important than temperature. Principal component analysis (PCA) of chemical and physical variables explained 85% of the total variation by the first three principal components, the first component (PCI) being defined by physical variables, explained 46% of the variation, while the temperature related PC2 explained 32% of the variation. Prediction of sensory variables by chemical or physical variables by means of par...

Prediction of sensory quality of strawberry jam by means of sensory quality attributes of fresh fruits

Sensory analysis was performed on fresh fruits, frozen non-cooked jam and traditionally cooked jam of 14 strawberry cultivars. The purpose was to characterise and compare the sensory quality of different strawberry cultivars and different types of jam. The results of the investigation were presented by means of multivariate modelling methods such as principal component analysis (PCA) and partial least squares regression (PLS). The sensory profile of cooked jam differed from that of fresh fruits and frozen jam, explaining 75% of the total variation in the first component. Cooked jam scored high for sweet taste, stickiness, bitter taste, earthy flavour, off-flavour and total intensity of taste. Frozen jam had many of the same sensory characteristics as fresh fruits and scored high for strawberry flavour, fruity flavour and whiteness, while fresh fruits scored highest for colour strength, hue and sour taste. As analysed by means of PLS, sensory colour and flavour variables of fresh fruits were able to predict 35% of sensory cooked jam variables. Analysing early cultivars alone, sensory fresh fruit variables were able to predict 69% of sensory cooked jam variables. © 2000 Society of Chemical Industry

The effect of temperature on sensory quality, chemical composition and growth of carrots (Daucus carota L.). III. Different diurnal temperature amplitudes

SummaryData from experiments with carrots grown in phytotrons under different day and night temperatures at two locations in Norway and three harvesting dates were treated by means of Principal Component Analysis (PCA). No effect of the single temperature amplitudes were found, the significant main effects were due to the mean temperature levels of 12 and 188C, location and harvest date. The PCA visualized the effect of mean temperature level on sensory, chemical and physical variables. Differences between the two groups were mainly caused by variation in sensory variables, the first group being characterized by high score for whiteness, sweetness, acidic taste, crispness, juiciness, glucose, fructose and root length. The other group had a high score for colour, odour, overall taste and flavour parameters, firmness, dry matter, sucrose, a and b-carotene, root weight and root diameters.

Relationship between physical and chemical characteristics of carrots grown at northern latitudes

SummaryThe study describes the variation in physical and chemical data from a trial with carrots grown outdoors and in plastic greenhouses during two years at three geographical locations in Norway, 59°40’N, 63°28’N and 69°39’N, and analysed by principal component analysis (PCA), partial least square and multiple linear regression (MLR). The most important principal component (PCI) to describe the total variation was the root weight, root diameters, and the carotene content. PCI described 53–65% of the total variation. Further 13–17% of the variation could be explained by a second component which included the air temperature a fortnight prior to harvest, and the sugar content of the roots. PLS and MLR revealed relationships between chemical and physical variables. Physical variables were able to predict 55% of the variation in chemical variables by the first two PLS components. The biological development of the carrot roots was best described by the root weight and a computed variable containing root dry ...

Influence of packaging materials and temperature on the glycoalkaloid content of potato tubers

Abstract The potato variety BEATE was packed in different coloured paper, polyester mesh and polyethylene bags. The samples were stored for 1 and 2 weeks at 5 and 23 °C. High storage temperature increased the solanine content significantly in all packaging variables. The highest content of glycoalkaloids was found in a blue polyethylene bag with high light transmission and the lowest glycoalkaloid content occurred in a paper bag coated with black polyethylene inside. To avoid high levels of glycoalkaloids, potato tubers should be kept cool during marketing.