Czech Journal of Food Sciences, 2018 (vol. 36), issue 2
Chemical composition of propolis from the Baha region in Saudi ArabiaFood Chemistry and Safety
Ohood Hasan ALMOHAMMADI, Abdulsallam BAKDASH, Nael Abu TAHA, Ali ABU-RUMMAN, Sachil KUMAR
Czech J. Food Sci., 2018, 36(2):109-118 | DOI: 10.17221/119/2017-CJFS 
The chemical composition of organic compounds in the extractable organic matter of propolis collected from the Baha region of Saudi Arabia was investigated. The propolis samples were extracted with methanol followed by column chromatography and collected in fractions (15 ml), then analysed by gas chromatography-mass spectrometry (GC-MS). Samples were injected with and without derivatization using BSTFA simultaneously. The results showed that a total of 61 chemical compounds were characterized and identified by analysing each of the fractions. Out of these, 33 compounds have not been reported previously. The Baha sample contains a high amount of aromatic...
The use of UniProtKB/BIOPEP for the analysis of oat globulin physicochemical parameters and bioactivityFood Microbiology and Safety
Iwona SZERSZUNOWICZ, Dorota NAŁĘCZ
Czech J. Food Sci., 2018, 36(2):119-125 | DOI: 10.17221/455/2016-CJFS
The physico-chemical properties of oat proteins (globulins) were determined and an analysis was done whether products of in silico proteolysis contain mono- and multi-functional peptides with various biological activity. The MW(s), calculated by the ProtParam program, for precursors of 12S and 11S globulins and proteins without signal peptides were in the range of 50.78-61.86 kDa. The pH at which the solubility of the proteins under analysis was the lowest ranged from 7.29 to 9.44. A simulation of proteolysis with three enzymes (pepsin, trypsin, and chymotrypsin A) in the optimum conditions of the enzyme action can produce 6-8 bi-functional,...
Determining the optimal method for DNA isolation from fruit jamsFood Microbiology and Safety
Tereza SOVOVÁ, Barbora KŘÍŽOVÁ, Jaroslava OVESNÁ
Czech J. Food Sci., 2018, 36(2):126-132 | DOI: 10.17221/340/2017-CJFS
DNA extraction is a crucial step in PCR analysis especially when analysing food samples that can be degraded and can potentially contain PCR-inhibiting substances. In this study, we compared the suitability of three DNA extraction methods - two kits: DNeasy® Plant Mini Kit and NucleoSpin® Food, and the CTAB method - for DNA extraction from commercial fruit jams. Fourteen jams with different contents of fruit, sugar and other additives were extracted in triplicate using the above-mentioned methods directly and after a washing step. The concentration and optical density were analysed using UV spectrophotometry and the amplifiability...
Starch nanoparticles - two ways of their preparationFood Technology and Economy, Engineering and Physical Properties
David CHENA ALDAO, Evžen ŠÁRKA, Pavel ULBRICH, Eva MENŠIKOVÁ
Czech J. Food Sci., 2018, 36(2):133-138 | DOI: 10.17221/371/2017-CJFS
Starch nanoparticles (SNP) originate from the disruption of the semi-crystalline structure of starch granules. They are very useful in food packaging technology because they increase the mechanical and water vapour resistance of the matrix as well as hinder its recrystallisation during storage in high humidity atmospheres. In medicine, SNP are suitable as carriers in modulated drug delivery for immobilized bioactive or therapeutic agents. Depending on the method of preparation, nanoparticles with different physicochemical, technical or mechanical properties can be obtained. Two different methods of preparation were characterized and compared in this...
Reduced microbiological contamination following irrigation of germinated seed for foodsFood Technology and Economy, Engineering and Physical Properties
Honorata DANILČENKO, Elvyra JARIENÉ, Dalé TELEVIČIUTÉ, Skaidré SUPRONIENÉ, Jurgita KULAITIENÉ, Živilé TARASEVIČIENÉ, Alvyra ŠLEPETIENÉ, Judita ČERNIAUSKIENÉ
Czech J. Food Sci., 2018, 36(2):139-145 | DOI: 10.17221/267/2017-CJFS
Germinated seeds are rich in various nutrients but are vulnerable to fungal contamination which favours micromycete formation on the sprouts. The main aim of this work was an investigation of strategies to reduce the contamination of sprouted seed foods. Over the course of 96 hours of sprouting, seeds of organic spring wheat (Triticum aestivum L.), winter wheat (Triticum aestivum L.), naked oat (Avena nuda L.), triticale (xTriticosecale) and rye (Secale cereale L.) were irrigated in water filtered using the Pazdroid Med-1500 filtration device with and without 4% ethyl alcohol. Germinated seeds were stored...
Use of wheat straw and chicken feather hydrolysates as a complete medium for lactic acid productionFood Technology and Economy, Engineering and Physical Properties
Lucia GHARWALOVÁ, Leona PAULOVÁ, Petra PATÁKOVÁ, Barbora BRANSKÁ, Karel MELZOCH
Czech J. Food Sci., 2018, 36(2):146-153 | DOI: 10.17221/461/2017-CJFS
Biotechnological production of lactic acid has experienced a boom that is hindered only by the lack of low-cost, abundant material that might be used as a substrate for lactic acid bacteria. Such material should contain not only carbon but also complex nitrogen sources, amino acids and vitamins necessary for the balanced growth of the bacteria. Here, for the first time, a combination of hydrolysates of wheat straw and chicken feathers was used as a complete waste cultivation medium for lactic acid production. It was shown to be a promising substrate for lactic acid production, reducing the medium price by 73% compared with MRS broth, providing more...
Antioxidant and antimicrobial potential of artichoke (Cynara scolymus L.) extract in beef pattiesFood Technology and Economy, Engineering and Physical Properties
Haluk ERGEZER, Halil Ibrahim KAYA, Ömer ŞIMŞEK
Czech J. Food Sci., 2018, 36(2):154-162 | DOI: 10.17221/179/2017-CJFS
The antioxidant and antimicrobial potential of artichoke extract (AE) in raw beef patties (RBPs) was evaluated during the storage. The RBPs were prepared with the addition of 500 and 1000 ppm AE. Also, Escherichia coli ATCC25922 and Listeria monocytogenes ATCC19118 were inoculated to each RBP to follow the antimicrobial activity. An evaluation of the instrumental colour, pH, total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, TBARS and microbiological properties was carried out during storage. The evaluation revealed that the a* value decreased significantly, so that the reduction...
Influence of post-harvest ripening on the levels of selected compounds in various cherry cultivarsFood Technology and Economy, Engineering and Physical Properties
Jan GOLIÁŠ, Naděžda VRCHOTOVÁ, Jarmila KOŽÍŠKOVÁ, Petr KOTAS, Jan TŘÍSKA
Czech J. Food Sci., 2018, 36(2):163-168 | DOI: 10.17221/149/2017-CJFS
The stability of the main sugars and the organic acids neochlorogenic acid, p-coumaroylquinic acid and rutin was assessed in the Vanda, Napoleonova, Kordia, New Moon, Sweetheart, and Regina sweet cherry (Prunus avium L.) cultivars during post-harvest storage. Neochlorogenic acid was the predominant phenolic acid in these sweet cherry cultivars followed by p-coumaroylquinic acid. Rutin concentrations ranged from 0.5 ± 0.38 to 12.35 ± 2.84 mg/kg of homogenate and its concentration was higher in the Sweetheart, Kordia, and Regina cultivars in the postharvest time.
Effects of osmotic dehydration vacuum-microwave drying on the properties of tilapia filletsFood Technology and Economy, Engineering and Physical Properties
Bing LIU, Jun CAO, Ai-Guo FENG, Yan LIU, Qun YU, Chuan LI, Zhen-Hua DUAN
Czech J. Food Sci., 2018, 36(2):169-174 | DOI: 10.17221/137/2017-CJFS
A novel drying method based on vacuum-microwave dehydration was developed to investigate the effects of different microwave gap ratios (MGR), microwave times, power densities and degrees of vacuum after osmotic pre-treatment on tilapia fillets. The results showed that the moisture value of fillets was decreased with the increased drying time, power density and vacuum degree. The shrinkage ratio, rehydration ratio and total colour change increased with elevated microwave time and power density. A high degree of vacuum was beneficial to the qualities of fillets. In conclusion, tilapia fillets retained their original quality properties after osmotically...
Changes in the levels of selected organic acids and sugars in apple juice after cold storageFood Technology and Economy, Engineering and Physical Properties
Ján MEZEY, Ivana MEZEYOVÁ
Czech J. Food Sci., 2018, 36(2):175-180 | DOI: 10.17221/165/2017-CJFS
Apples are a source of sugars, acids, and various biologically active compounds, such as phenolic compounds, which are responsible for most of the antioxidant activities of the fruit. The aim of this study was to evaluate how the cold storage of apple fruits affects the nutritional composition of selected organic acid and sugar content in juice in comparison to juice from fresh fruits. Statistical differences were confirmed between the content of citric acid, malic acid, total acid, pH, sucrose, fructose and glucose in juice from fresh fruits and from juice stored for 140 days. No statistical differences were observed between juice from fresh fruit...
Biochemical changes of Iranian probiotic Lighvan cheeseFood Technology and Economy, Engineering and Physical Properties
Alireza SHAHAB LAVASANI
Czech J. Food Sci., 2018, 36(2):181-186 | DOI: 10.17221/453/2016-CJFS
Lighvan cheese from ewe and goat milk was produced according to a traditional protocol, and with the addition of 9 log10 cfu/g fresh cells of Bifidobacterium lactis subsp. animalis. Probiotic Lighvan cheese was studied to determine the survival of B. lactis subsp. animalis and biochemical changes during 60 days of ripening of probiotic Lighvan cheese. Lipolysis level and organoleptic assessments were analysed. B. lactis subsp. animalis cells survived in cheese samples at concentrations up to 6.84 log10 cfu/g for at least 60 days of storage time. The lipolysis level increased...
Convective and microwave drying of onion slices regarding texture attributesFood Technology and Economy, Engineering and Physical Properties
Özge SÜFER, Hande DEMIR, Seda SEZER
Czech J. Food Sci., 2018, 36(2):187-193 | DOI: 10.17221/310/2017-CJFS
The textural characteristics of onion slices (Allium cepa L.) of 3- and 7-mm thicknesses undergoing convective drying (50, 60, and 70°C) and microwave drying (68, 204, and 340 W real effective power levels) techniques with or without pre-treatment were evaluated. Pre-treatment consisted of dipping into brine solution (8% NaCl). Texture profile analysis at 25% compression was applied and hardness, chewiness, springiness and gumminess values of onions were recorded. As the temperature (convective) or real effective power level (microwave) increased, the hardness and chewiness levels of dried onion slices were enhanced. The values of these parameters...