Tag Archives: colour

86-92 P. Kic
Process of heat treatment and changes in garlic properties
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Process of heat treatment and changes in garlic properties

P. Kic*

University Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: kic@tf.czu.czs

Abstract:

This paper aims to present the results of research focused on the heat treatment of garlic (Allium sativum) into black garlic. The research compared three varieties of classic kitchen garlic (Dukat, Topaz and Sabagold), grown in the Czech Republic. The course of heat treatment in a hot air dryer was investigated at 60 °C. Changes in the weight and moisture of the samples were monitored gravimetrically for 78 days. The dry matter content was measured gravimetrically after drying at 105 °C. There were certain differences between the varieties studied. The intensive decrease in water content, dry basis u (g g-1) during the first 20 days was the fastest in the Topaz variety, when it dropped below 0.4 (g g-1) after only 9 days. In the Dukat and Sabagold variety water content, wet basis w (%), from the original values w = 62 to 66% dropped below 30% within 20 days, and in the Topaz variety below 20%. Changes in the colour of garlic cloves were measured by A CM-600d spectrophotometer. During the black garlic processing, its gradual darkening occurred. Lightness L* decreased in the Dukat variety from 80.39 to 27.47, Topaz from 78.29 to 29.09 and Sabagold from 83.64 to 28.72. In all varieties, colour changes occurred. Greenness (-a*) changed from the 9th day to a redness (a*) whose saturation gradually decreased. The yellowness (b*) of all varieties also decreased significantly.

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1472–1484 R. Soidla, K. Kerner, M. Tepper, A. Tänavots, T. Kaart and I. Jõudu
The effect of ageing on chosen quality characteristics of skeletal muscles of Aberdeen Angus bulls
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The effect of ageing on chosen quality characteristics of skeletal muscles of Aberdeen Angus bulls

R. Soidla¹, K. Kerner¹, M. Tepper¹, A. Tänavots¹²*, T. Kaart² and I. Jõudu¹

¹Estonian University of Life Sciences, Institute of Veterinary Medicine and Animal Sciences, Chair of Food Science and Technology, Fr.R. Kreutzwaldi 56/5, EE51006 Tartu, Estonia
²Estonian University of Life Sciences, Institute of Veterinary Medicine and Animal Sciences, Chair of Animal Breeding and Biotechnology, Fr.R. Kreutzwaldi 62, EE51006 Tartu, Estonia
*Correspondence: alo.tanavots@emu.ee

Abstract:

The objective of the trial was to study the qualitative parameters of two muscles of Aberdeen Angus bulls with 250–300 kg carcass weight. After slaughter, longissimus thoracis et lumborum (LD) muscle and unseparated semimembranosus and adductor femoris (SMA) muscles were removed from the chilled carcasses. Muscles were vacuum-packed and wet aged at +2 °C for 10, 14, 18 and 20 days. Meat pH, electrical conductivity, shear force and colour were measured in all ageing times. Two thermal treatment methods (sous-vide (SV) and grilling) were used to determine cooking losses. The effects of muscles, ageing times and muscles by ageing times interaction was found with two-factorial analysis of variance. The effects of muscles, ageing times and muscle groups by ageing time interaction for raw and SV treated meat shear force was significant. Ageing decreased SV treated meat shear force from day 10 (40.8 N) to 18 (29.7 N). Fresh and SV treated LD muscle was tougher compared to the SMA muscle group, but SM showed a better response to the tenderness within 20 days of ageing. Redness and yellowness value was higher in the SM group in comparison to LD. Muscles showed good colour (lightness, redness and yellowness) stability within ageing for 20 days. No interactions were found between muscle groups and ageing times for SV treated and grilled beef cooking losses. However, SV treated meat lost more weight than grilled meat slices. The present study suggests that the optimal ageing time for meat is 18 days when the grilled meat cooking loss is the lowest.

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556–568 J. Prchalová, H. Čížková, R. Ševčík, K. Hanušová and A. Rajchl
Evaluation of shelf-life of fruit baby food
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Evaluation of shelf-life of fruit baby food

J. Prchalová, H. Čížková, R. Ševčík, K. Hanušová and A. Rajchl*

Department of Food Preservation, University of Chemistry and Technology Prague,
Technická 5, CZ 160 28 Prague 6, Czech Republic
*Correspondence: ales.rajchl@vscht.cz

Abstract:

Fruit baby food is an important food source in infant nutrition. This ambient stable product is processed using heat treatment and can be stored for one or more years at ambient temperature. An accelerated shelf-life storage test of fruit baby food was carried out. Sets of samples were stored at various storage temperatures (40, 55, 70 and 90 °C) for 3 weeks. Selected markers were followed and correlated with sensory evaluation during the storage. The markers were: DPPH, total phenols, ascorbic acid, 5-HMF, furfural and colour (expressed as L, a*, b* and nE). Kinetic data (reaction rate constants, activation energies, Q10, z values) were calculated. The aim of the paper was to evaluate shelf-lives of fruit baby food. The colour parameters, especially nE, seem to be a robust criterion which could be used to predict shelf-lives of fruit baby food.

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712-718 A. Radzevičius, R. Karklelienė, P. Viškelis, Č. Bobinas,R. Bobinaitė and S. Sakalauskienė
Tomato (Lycopersicon esculentum Mill.) fruit quality and physiological parameters at different ripening stages of; Lithuanian cultivars
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Tomato (Lycopersicon esculentum Mill.) fruit quality and physiological parameters at different ripening stages of; Lithuanian cultivars

A. Radzevičius, R. Karklelienė, P. Viškelis, Č. Bobinas,R. Bobinaitė and S. Sakalauskienė

Lithuanian Institute of Horticulture. LT-54333, Babtai, Kauno 30, Kaunas distr., Lithuania;e-mail: a.radzevicius@lsdi.lt

Abstract:

Four cultivars (‘Neris’, ‘Svara’, ‘Vytėnų didieji’, ‘Jurgiai’) and one hybrid (‘Vaisa’) of tomato (Lycopersicon esculentum Mill.) were investigated at the Lithuanian Institute of Horticulture from 2007─2008.During this investigation fruit quality and physiological parameters were evaluated: thelycopene and β-carotene contents, colour indices (CIE L*a*) and hue angle (h°) with chroma (C) at four different fruit ripening stages (I stage – green, II stage – beginning of ripening, III – not fully ripened, IV – fully ripened)A significant increase in lycopene and β-carotene content at each successive ripeningstage of tomato fruit was recorded. Tomato fruit colour became darker and the ratio of red to green colour increased during the ripening process. Chroma value increased with a change of tomato colour from green to light red, and subsequently declined at the red fruit stage, but chroma of the hybrid ‘Vaisa’ increased at all ripening stages.External colour was expressed in terms of hue angle. All the analyzed tomato cultivarsdeveloped a similar colour when mature, with average hue angles generally being close to 40 degrees, but the cultivar ‘Neris’ had lower hue value (32 degrees).

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