Czech Journal of Food Sciences, 2017 (vol. 35), issue 6
Antioxidant activity and phenolic acid content of selected vegetable brothsFood Analysis, Food Quality and Nutrition
Bilge Ertekin Filiz, Nazli Korkmaz, Nilgun H. Budak, Atif C. Seydim, Zeynep B. Guzel Seydim
Czech J. Food Sci., 2017, 35(6):469-475 | DOI: 10.17221/458/2016-CJFS 
The antioxidant activity and content of phenolic substances in vegetable broths were determined. Green beans, beetroots, courgettes, onions, parsley, carrots, cabbages, celery, broccoli, spinach, cauliflowers, and tomatoes were subjected to boiling. Fresh vegetables and vegetable broths were analysed for ascorbic acid content, total phenolic content, ORAC and TEAC values. Phenolic acids were quantified using HPLC. The ascorbic acid content of vegetables ranged from 5-109 mg/100 ml, while no ascorbic acids could be detected in vegetable broths. Total phenolic content was between 17-1729 mg GAE/l for all samples. ORAC and TEAC values of vegetable broths...
Adsorption of apple polyphenols onto β-glucanFood Analysis, Food Quality and Nutrition
Lidija Jakobek, Petra Matić, Vedrana Krešić, Andrew R. Barron
Czech J. Food Sci., 2017, 35(6):476-482 | DOI: 10.17221/75/2017-CJFS
The adsorption of polyphenols from apples, a good source of polyphenols in the human diet, onto β-glucan, a soluble dietary fibre were studied. Polyphenols were extracted from the flesh and peel of two apple varieties (wild apple and Slavonska srčika) and adsorbed onto β-glucan for 16 hours. The adsorption capacities (mg/g) and equilibrium polyphenol concentrations (mg/l) were modelled with Freundlich and Langmuir isotherms. Polyphenols from the flesh and peel showed different behaviours - flesh polyphenols exhibited greater affinity and peel polyphenols greater theoretical adsorption capacity. The analysis of individual polyphenols with...
Identification of volatile flavour components of Tuber melanosporum using simultaneous distillation-extractionFood Analysis, Food Quality and Nutrition
Tao Liu, Tao Feng, Wanchao Chen
Czech J. Food Sci., 2017, 35(6):483-487 | DOI: 10.17221/31/2017-CJFS
Black truffles are famous for their unique flavours. Headspace solid-phase microextraction and the electronic nose have been used to analyse their flavours in some investigations. In a previous work, the volatile flavour compounds in black truffles harvested in China were extracted using simultaneous distillation-extraction (SDE) and analysed using gas chromatography-mass spectrometry (GC-MS). Extraction conditions were optimised in that previous study and are now applied in the present work. The temperature of the solvent flask was maintained at 70°C using a water bath and the samples were placed in boiling water; extraction time was 3 hours. Fifty-seven...
Geographical origin of honey from eight sub-regions of Bosnia and HerzegovinaFood Analysis, Food Quality and Nutrition
Vildana Alibabić, Melisa Oraščanin, Nada Vahčić
Czech J. Food Sci., 2017, 35(6):488-495 | DOI: 10.17221/82/2017-CJFS
Principal component analysis (PCA) and cluster analysis (CA) were used to define the geographical origin of three types of monofloral (chestnut, linden, and acacia), two types of multifloral (meadow and mixed), and forest honey produced over two consecutive harvest seasons in the Una-Sana Canton (Bosnia and Herzegovina), which is geographically divided into eight sub-regions. Statistical analysis was applied to the measurement of physico-chemical and sensory parameters, as well as micro- and macronutrient (K, Na, Mg, Zn, Fe, Mn, and Al) content, along with some heavy metals (Cd, Pb, and As). Using the PCA method the characteristic parameters for all...
Effect of fermentation on microbiological, physicochemical and physical characteristics of sourdough and impact of its use on bread qualityFood Technology and Economy, Engineering and Physical Properties
Alba Casado, Alberto Álvarez, Leticia González, Domingo Fernández, José L. Marcos, María E. Tornadijo
Czech J. Food Sci., 2017, 35(6):496-506 | DOI: 10.17221/68/2017-CJFS
The chemical, microbiological, and texture characteristics and rheological properties of sourdoughs were studied in the course of fermentations at 25 and 35°C over a period of 72 hours. After 6 h of fermentation, pH decreased rapidly in the sourdough at 35°C. However, after 72 h the pH values were slightly lower in the sourdough at 25°C. To obtain sourdough with an optimum pH, 11 h were required at 25°C and 9 h at 35°C. Acidity increased more slowly in sourdough at 25°C. However, values were similar in both types of dough after 24 h, but higher in dough at 25°C after 72 hours. Counts of lactic acid bacteria were slightly higher in sourdough at 35°C...
Optimisation of extrusion variables for the production of corn snack products enriched with defatted hemp cakeFood Technology and Economy, Engineering and Physical Properties
Antun Jozinović, Đurđica Ačkar, Stela Jokić, Jurislav Babić, Jelena Panak Balentić, Marija Banožić, Drago Šubarić
Czech J. Food Sci., 2017, 35(6):507-516 | DOI: 10.17221/83/2017-CJFS
The effects of defatted hemp cake added to corn grits (at ratios of 0, 5, and 10% DM), the moisture content of the mixtures (15, 20, and 25%) and the temperature in the extruder ejection zone (150, 165, and 180°C) on the physical properties of extruded products have been investigated. Statistical optimization of investigated extrusion conditions using the response surface methodology was performed. The hemp cake was completely defatted by means of a supercritical CO2 extraction. The extrusion was performed on a laboratory single screw extruder and regulated by the following parameters: temperature in the dosing and compression zone (120 and 150°C),...
Properties of fish and beef restructured by MTG derived from Streptomyces mobaraensis grown in media based on enzymatic hydrolysates of sorghumFood Technology and Economy, Engineering and Physical Properties
Guadalupe Rodríguez Castillejos, José Ramírez de León, Guadalupe Bustos Vázquez, Octelina Castillo Ruíz
Czech J. Food Sci., 2017, 35(6):517-521 | DOI: 10.17221/422/2016-CJFS
The efficiency of microbial transglutaminase (MTG) obtained from Streptoverticillum ladakanaum fermentation of sorghum grain and DDGS hydrolysates (HMTG) in increasing the mechanical properties of restructured meat and fish products was evaluated in this study. Gels were obtained by adding HMTG or commercial MTG at 0.3 U/g, and controls lacked enzyme. All treatments were supplemented with 2.0% NaCl. The gels with enzyme showed a lower amount of expressible water, similar to those obtained with CMTG (6% for fish gels and 8% for beef gels). Texture values were also similar. The results showed the feasibility of employing MTG obtained from sorghum...
Effect of the dough mixing process on the quality of wheat and buckwheat proteinsFood Technology and Economy, Engineering and Physical Properties
Marcela Sluková, Julie Levková, Alena Michalcová, Šárka Horáčková, Pavel Skřivan
Czech J. Food Sci., 2017, 35(6):522-531 | DOI: 10.17221/220/2017-CJFS
The changes in the structure of cereal proteins during the mixing of flour into dough was described and evaluated. Wheat gliadins and glutenins (gluten proteins) have unique physical properties and play an important role in breadmaking. The effect of mixing time on the formation and the structure of the gluten network was determined using scanning electron microscopy (SEM). Buckwheat flour (gluten-free) was used to compare the development of structure during the mixing process.