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Open access

Maria João Afonso, Marta Magalhães, Luana Fernandes, Marina Castro and Elsa C.D. Ramalhosa

Abstract

In the present work the temperature effect on rheological properties of Portuguese honeys was studied for the first time. Two unifloral honeys – heather and rosemary – and a polyflower honey were analyzed. All honeys showed flow independence over time and behaved as Newtonian fluids at the studied temperature and shear rate ranges. For all honeys it was found that the viscosity decreased with temperature and the rosemary honey was the one that always presented the lowest viscosity at 30°C (6120 mPa·s), 50°C (603 mPa·s) and 70°C (145 mPa·s). The temperature dependence of viscosity was well described by the K0×eAT-B equation. Nevertheless, good regression coefficients were also obtained when fitting the experimental data to the Arrhenius model, showing the rosemary honey to be less temperature sensitive. The results obtained in this study are of great interest to beekeepers and industrials that handle and prepare eatable honey-based products because they will be better informed about the best type of honey to use.

Open access

Neslihan Göncüoğlu Taş and Vural Gökmen

Abstract

Proximate composition, profiles of amino acids, sugars, organic acids, vitamins and minerals of fourteen Turkish hazelnut varieties harvested in 2013 and 2014 were investigated. Glutamic acid, arginine and aspartic acid were the most predominant amino acids, representing of about 50% of hazelnut protein. Individual amino acid profiles showed significant differences depending upon the harvest year (p<0.05). Concentration of sucrose was the highest followed by fructose, glucose, stachyose, raffinose and myo-inositol, respectively. Phytic acid was predominant organic acid in all varieties, followed by malic acid. Independent of the variety, hazelnuts were rich in pantothenic acid, nicotinic acid, pyridoxal, biotin, thiamine, nicotinamide. Pantothenic and nicotinic acid were significantly higher in most of the varieties in harvest year 2014. Potassium was the most predominant mineral, followed by magnesium, calcium, sodium, manganese, zinc, iron and copper, respectively.

Open access

Shunmin Wang, Jianfei Wang and Yubao Guo

Abstract

Tartary buckwheat (Fagopyrum tataricum) seeds were irradiated with microwaves at various power levels of 200, 400, 600 and 800 W for 10 or 30 s. The irradiated grains were germinated for 3, 5, and 7 days and harvested. The germination rate of the tartary buckwheat seeds and contents of some compounds in the sprouts were investigated. The results showed that the exposure to 600 W microwaves for 10 s resulted in the highest final germination rate after 7 days of germination, which was 2 times that of the control. The exposure of seeds to 800 W for 30 s showed the lowest germination rate (approximately 10%), which decreased by 87% compared with the control (p<0.05). The exposure at 600 W for 30 s stimulated the total flavones content, reduced the sugar and soluble protein contents, and increased the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The highest free amino acid content (11 mg/g) was observed in 5-day sprouts exposed to 800 W for 10 s. Moreover, the microwave treatment had a positive effect on the catalase (CAT) and superoxide dismutase (SOD) activity.

Open access

Antonija Tomić, Marin Mihaljević Žulj, Željko Andabaka, Ivana Tomaz, Snježana Jakobović and Ana Jeromel

Abstract

The aim of this study was to determine concentrations of individual o rganic acids, polyphenolic and aromatic compounds in blackberry wine, and to define the influence of different yeast strains (Uvaferm BDX and Lalvin 71B) and pectolytic enzymes (L allzyme OE and Lallzyme EX-V) on the chemical composition and quality of the wine. Blackberry wines were produced in five variants, depending on yeasts and enzymes used: BDX OE, BDX EX-V, 71B OE, 71B EX-V, and Control without the addition of selected yeasts and enzymes. All blackberry wine variants were defined by a relatively high sum of organic acids. The citric acid was the predominant one, which concentrations ranged from 5.42 to 7.31 g/L. The concentration of gallic acid ranged from 19 to 37 mg/L and was in dependence of the yeast strain used. The concentration of procyanidin B2 which was the predominant flavan-3-ol compound, ranged from 103 to 117 mg/L, and there were no significant differences between individual wine variants in the experiment. Rutin is the predominant compound in the flavonol group, followed by quercetin-3-O-glucoside. The predominant one among the anthocyanins was cyanidin-3-O-glucoside whose concentrations ranged from 134 to 229 mg/L. According to the obtained results, the yeast strain and pectolytic enzymes had a significant impact on the concentration of individual anthocyanins in the analyzed wines. The predominant group of aromatic compounds was monoterpenes, among which linalool was the most prominent in all of blackberry wine variants, except in Control.

Open access

Elżbieta Huzar, Małgorzata Dzięcioł, Alicja Wodnicka, Harun Örün, Arda İçöz and Erkan Çiçek

Abstract

The yield and composition of essential oil obtained from the fruits of coriander (Coriandrum sativum L.) cultivated in Poland were investigated. Experiments were carried out by means of the hydrodistillation method using Clevenger and Deryng apparatus. No effect of the apparatus' construction on the essential oil yield was observed during a 2-h process (yield of 1.62%). The composition of the coriander essential oil was determined by using gas chromatography with mass spectrometry (GC-MS). The main components were linalool (78.45%), α-pinene (5.03%), camphor (3.90%), γ-terpinene (3.80%), D-limonene (2.58%) and geranyl acetate (2.13%). Moreover, the influence of different factors, such as time of hydrodistillation, sodium chloride addition and method modification by using microwave heating on essential oil yield, was studied. The addition of sodium chloride to distilled water did not affect the yield of essential oil, but slightly increased the content of camphor. Replacing conventional heating with microwaves during 15-min experiments enhanced the yield of essential oil from 1.20 to 1.35% and had a slightly greater influence on its composition, increasing the contents of some less volatile components: linalool, camphor, geraniol, p-cymene and D-limonene. The results obtained indicate that microwave heating may be a supporting method for the production of coriander essential oil using the hydrodistillation process.

Open access

Adrian R. Górecki, Wioletta Błaszczak, Jacek Lewandowicz, Joanna Le Thanh-Blicharz and Kamila Penkacik

Abstract

Buckwheat starch was subjected to cycles of high pressure-cooling (P-CC) or autoclaving-cooling (A-CC) combined with pullulanase debranching to determine changes in resistant starch (RS) content, digestibility, rheological properties and microstructure. Native buckwheat starch had 11.9 g/kg of RS, while the highest RS content (58.7 g/kg) was reached after A-CC and 6 h of pullulanase treatment. Among the P-CC samples, the highest RS content (43.3 g/kg) was obtained after treatment with 600 MPa/9 min and 6 h pullulanase debranching. The digestibility of the starch samples was negatively correlated with RS content and its highest values were noted for native and P-CC 200 MPa preparations subjected to 2 and 16 h of pullulanase treatment (95.18–95.35%). Buckwheat starch A-CC preparations after 6 h of pullulanase treatment exhibited the lowest digestibility (85.87%). Rheological analysis of 6% starch pastes showed that all investigated samples demonstrated a non-Newtonian flow, pseudoplastic properties and thixotropy. The Ostwald de Waele rheological model was very well fitted to the flow curves of the investigated pastes (R2>0.98). Both P-CC and A-CC reduced the consistency coefficient (K) and thixotropy values, while the flow behavior index (n) was increased only after P-CC treatment. The P-CC and A-CC treatment resulted in starch granule breakdown and porous gel structure formation, differing in surface properties.

Open access

Igor Sepelevs, Valentina Stepanova and Ruta Galoburda

Abstract

The main objective of the present study was to investigate the effect of spray- and freeze-drying techniques on the microencapsulation of a gallic acid compound using the acid-hydrolyzed low dextrose equivalent potato starch as a wall material. During the experiment, it was possible to achieve encapsulation efficiency of 70–84% for the freeze-dried and 65–79% for spray-dried samples, without statistically significant difference (P>0.05) in the encapsulation efficiency between the mentioned methods. Spray-dried samples formed spherical capsules with a higher number of micropores. Meanwhile, freeze-dried samples were shapeless, exposed larger pore volume (from 2.4×10−3 to 9.5×10−3 cm3/g against 1.2×10–3 4.9×10−3 cm3/g; analyzed by Barrett-Joyner-Halenda method) and overall higher surface area (0.632–1.225 m2/g against 0.472–1.296 m2/g; analyzed by Barrett-Joyner-Halenda method). Due to this fact, more gallic acid molecules were exposed to environmental factors and can be counted as losses. In addition, freeze-dried samples demonstrated lower water activity than spray-dried samples (0.075±0.014 against 0.178±0.008). Results showed that it is not practical to use freeze-drying for modelling encapsulation for food industry without a special necessity for protection of easily degradable chemical compounds. The present work makes a basis for the future studies of the microencapsulated phenolics application in food production.

Open access

Agnieszka Wójtowicz, Marta Zalewska-Korona, Ewa Jabłońska-Ryś, Krystyna Skalicka-Woźniak and Anna Oniszczuk

Abstract

The paper discusses the influence of the addition of freeze-dried tomatoes on the chemical composition and selected physical properties of extruded corn snacks. Corn grits were replaced with dried tomatoes in the amount from 5 to 30% of corn mass. The total lycopene and phenolic content, the scavenging ability and the ferric reducing antioxidant power were determined along with the content of neochlorogenic, chlorogenic, p-coumaric acids and rutin. Also evaluated were selected physical properties, colour and the sensory profile of corn snacks enriched with tomatoes. A greater tomato addition increased the volume of bioactive compounds, especially the total phenolic content. Snacks enriched with tomato exhibited a lower expansion ratio, water absorption and solubility indices, lightness and sensory characteristics but higher density, hardness and redness than corn snacks. Powdered tomato seems to be a functional additive with the high content of biologically-active compounds, and the enriched snacks displayed good physical properties if the tomato level did not exceed 20%. A higher amount of the additive significantly lowered the expansion as well as increased the hardness of snacks. Still, the corn products with 25 and 30% of powdered tomato were more valuable due to their much higher level of bioactive components compared with the regular corn snacks.

Open access

Xiaofei Xu, Jiguo Yang, Zhengxiang Ning and Xuewu Zhang

Abstract

A heteropolysaccharide, named L2, from Lentinula edodes has been proved to possess immunostimulating and anti-ageing activities in previous studies, but its acting mechanism was not completely understood. In this study, 1H NMR spectroscopy approach was employed to investigate the metabolic profiles of the urine from adult mice after L2 intervention. Using principal component analysis (PCA) and partial least squares-discriminate analysis (PLS-DA), 22 potential biomarkers were found to be mainly involved in some metabolic pathways: amino acid metabolism, energy metabolism, lipid metabolism, tricarboxylic acid (TCA) cycle, urea cycle and gut microbiota metabolism. Among them, the significantly altered metabolites include: elevated glutamate (75%) and creatine (64%); decreased proline (65%), betaine (58%), fucose (63%) and dimethylamine (59%). In conclusion, the present data is helpful to understand the mechanisms related to previously confirmed immunomodulation and anti-aging effects of L2, and provide valuable information for mining new functions of L2.