getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.54.02.16.4068

Synthesis of Octyl-β-Glucoside Catalyzed by Almond β-Glucosidase in Unconventional Reaction Media


Irina Mladenoska*

Department of Food Technology and Biotechnology, Faculty of Technology and Metallurgy, University of Ss. Cyril and Methodius, Rudjer Boskovic 16, MK-1000 Skopje, Republic of Macedonia




Article history:

Received  January 15, 2015
Accepted November 6, 2015
cc



Key words:

enzymatic synthesis, octyl-β-glucoside, biosurfactant, almond-β-glucosidase, monophasic octanol/water mixtures



Summary:
The reaction system for octyl-β-glucoside synthesis catalysed by the almond-β-glucosidase has been characterised. The monophasic octanol saturated with different amounts of water served as a reaction medium. Both the glucose and the activated substrate p-nitrophenyl-β-glucoside were examined as glycon donors. The reverse hydrolysis and the transglycosylation were both used as reaction models for this enzymatically catalysed alkyl-β-glucoside synthesis. The rate of synthesis of octyl β-glucoside (vS), the rate of hydrolysis, i.e. the glucose formation (vH) and the predicted yield (Y) were determined. The effect of water activity on the synthetic and hydrolytic activity of the enzyme was investigated. Both the rate of synthesis and the rate of hydrolysis increased with the increase of the water activity in the reaction system, showing their maximum values at the water activity close to the saturation level. Thus, the maximum ratio of vS/vH=0.165 was achieved at the water activity of 0.94. The predicted yields were 0.5, 0.75 and 14.19 % and were lower than the actually achieved yields of 19.45, 38 and 36.40 % at the water activities of 0.75, 0.84 and 0.94, respectively. The yield of octyl-β-glucoside in the reverse hydrolysis was only 15.2 %, i.e. 3.25 times lower than the yield obtained in the transglycosylation reaction with the water activity of 0.94. The solubility of glucose in pure octanol was only 1.5 mmol/L at the saturation level of 12 mmol/L in the presence of 10 mmol/L of p-nitrophenyl-β-glucoside, and it increased to 15.5 mmol/L in the presence of octyl-β-glucoside.




*Corresponding author:  email3 irinaetf@t-home.mk

getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.54.02.16.4063

Involvement of α-, γ- and δ-Tocopherol Isomers from Pumpkin (Cucurbita pepo L.) Seed Oil or Oil Mixtures in the Biphasic DPPH˙ Disappearance Kinetics



Dalibor Broznić, Gordana Čanadi Jurešić* and Čedomila Milin


Department of Chemistry and Biochemistry, Faculty of Medicine, University of Rijeka,
Braće Branchetta 20, HR-51000 Rijeka, Croatia



Article history:

Received  January 12, 2015
Accepted November 27, 2015
cc



Key words:

DPPH˙ disappearance kinetics, mathematical modelling, pumpkin seed oil, tocopherols




Summary:

The antioxidant activity of three types of pumpkin seed oil or oil mixtures (cold-pressed, produced from roasted seed paste and salad) produced in the northern part of Croatia and the kinetics of their behaviour as free radical scavengers were investigated using DPPH˙. In addition, the involvement of oil tocopherol isomers (α-, γ- and δ-) in different steps of DPPH˙ disappearance and their impact on the rate of reaction were analysed. The kinetics of DPPH˙ disappearance is a two-step process. In the first step, rapid disappearance of DPPH˙ occurs during the first 11 min of the reaction, depending on the oil type, followed by a slower decline in the second step. To describe DPPH˙ disappearance kinetics, six mathematical models (mono- and biphasic) were tested. Our findings showed that γ- and δ-tocopherols affected DPPH˙ disappearance during the first step, and α-tocopherol in the second step of the reaction. Moreover, α-tocopherol demonstrated 30 times higher antioxidant activity than γ- and δ-tocopherols. The results indicated the biphasic double-exponential behaviour of DPPH˙ disappearance in oil samples, due to the complexity of reactions that involve different tocopherol isomers and proceed through different chemical pathways.




*Corresponding author:  email3 gordanacj@medri.uniri.hr
                                      tel3 +385 51 651 132
                                      fax2 +385 51 678 895
                      
                     


getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.54.02.16.4336

Quality of Bread Supplemented with Antrodia salmonea-Fermented Grains


Rao-Chi Chien1, Enkhjargal Ulziijargal1 and Jeng-Leun Mau1,2,3*


1Department of Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung, Taiwan, R.O.C.
2NCHU/UCD, Plant and Food Biotechnology Center, NCHU, Taichung, Taiwan, R.O.C.
3Agricultural Biotechnology Center, NCHU, Taiwan, R.O.C.



Article history:
Received  June 29, 2015
Accepted December 4, 2015
cc

Key words:
Antrodia salmonea, mycelium, fermented grain, bread, colour, sensory evaluation


Summary:
Fermented grains of buckwheat, oat, embryo rice and wheat, which were prepared by solid-state fermentation with Antrodia salmonea, and the mycelium was used to substitute 7 % of wheat flour to make bread. No difference in proximate composition, texture profile and contents of non-volatile taste components was observed among bread samples. White bread and bread supplemented with mycelium and fermented grains looked different. Bread supplemented with fermented grains had similar thermal properties, which differed from those of white bread and bread supplemented with mycelium. Bread supplemented with fermented grains contained substantial mass fractions (on dry mass basis) of adenosine (0.92–1.96 μg/g), ergosterol (24.53–30.12 μg/g), ergothioneine (2.16–3.18 μg/g) and γ-aminobutyric acid (2.20–2.45 μg/g). In addition, bread supplemented with mycelium contained lovastatin (0.43 μg/g). White bread and bread supplemented with fermented grains had similar sensory results. Overall, fermented grains could be incorporated into bread to provide beneficial effects.






*Corresponding author:  email3 jlmau@dragon.nchu.edu.tw

                                      tel3 +886 4 2285 4313
                                      fax2 +886 4 2287 6211
                      
                     

getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.54.02.16.4319

Morphological Characterization and Chemical Composition of Fruits of the Traditional Croatian Chestnut Variety ‘Lovran Marron’


Igor Poljak1, Nada Vahčić2, Milica Gačić2 and Marilena Idžojtić1*


1University of Zagreb, Faculty of Forestry, Svetošimunska 25, HR-10000 Zagreb, Croatia
2University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia



Article history:
Received June 19, 2015
Accepted February 3, 2016
cc



Key words:

Castanea sativa, ‘Lovran Marron’ fruits, morphological characteristics, chemical composition



Summary:

‘Lovran Marron’ is the only known traditional Croatian variety of the sweet chestnut. The objective of this study is to specify qualitative and quantitative morphological characteristics and to analyze the chemical composition of the ‘Lovran Marron’ fruits as well as to compare them to Marušnjak fruits (trees from the ‘Lovran Marron’ seed) and fruits from the local natural sweet chestnut population. Seven morphological characteristics were measured: fruit mass, height, width and thickness, scar length and width, and the length of the longest intrusion of the seed coat into the kernel. Eight qualitative characteristics were estimated: embryony, degree of penetration of the seed coat into the kernel, fruit shape, glossiness and colour, kernel colour, hairiness towards the top of the fruit and the existence of longitudinal stripes. ‘Lovran Marron’ has desirable qualitative and quantitative fruit characteristics. The Marušnjak trees mostly have intermediate morphological traits of fruits in comparison with ‘Lovran Marron’ and trees from the natural population. ‘Lovran Marron’ had the smallest mass fractions on average of: K, Mg, Ca, Na, Mn, Cu and Fe. The highest mass fractions on average of these macro- and microelements were characteristic of the trees from the natural population. The highest average content of carbohydrates was recorded in the ‘Lovran Marron’ and the lowest in the fruits from the natural population. The Marušnjak fruits had intermediate water, protein, ash, carbohydrates, and macro- and microelement content. The content of Cd and Pb was lower in all samples than the maximum allowed amounts in the sweet chestnut fruits.





*Corresponding author:  email3 midzojtic@sumfak.hr
                                      tel3 +385 1 235 2522
                                      fax2 +385 1 235 2513
                      
                     

getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.54.02.16.3994

Effect of Various Sodium Chloride Mass Fractions on Wheat and Rye Bread Using Different Dough Preparation Techniques


Marta Ambrosewicz-Walacik1*, Małgorzata Tańska2, Daniela Rotkiewicz2 and Andrzej Piętak1


1Department of Mechatronics and IT Education, Faculty of Technical Sciences,
University of Warmia and Mazury in Olsztyn, Słoneczna Street 46A, PL-10-700 Olsztyn, Poland
2Chair of Food Plant Chemistry and Processing, Faculty of Food Sciences, University of Warmia and Mazury in Olsztyn, Cieszyński Square, PL-10-957 Olsztyn, Poland



Article history:
Received November 17, 2014
Accepted November 9, 2015
cc



Key words:

wheat bread, rye bread, sodium chloride mass fraction, bread properties



Summary:

This study assessed the selected properties of bread with reduced amount of sodium chloride. The bread was made from white and wholemeal wheat flour and rye flour. The dough was prepared using three techniques: with yeast, natural sourdough or starter sourdough. Sodium chloride was added to the dough at 0, 0.5, 1.0 and 1.5 % of the flour mass. The following bread properties were examined in the study: yield and volume of the loaf, moisture content, crumb firmness and porosity, and organoleptic properties. Reducing the mass fraction of added sodium chloride was not found to have considerable effect on bread yield, whereas it had a significant and variable effect on the loaf volume, and crumb firmness and porosity. Organoleptic assessment showed diverse effects of sodium chloride addition on sensory properties of bread, depending on the type of bread and the dough preparation method. Reduced mass fractions of sodium chloride changed the organoleptic properties of bread made with yeast and with starter sourdough to a greater extent than of bread prepared with natural sourdough.





*Corresponding author:  email3 marta.ambrosewicz@uwm.edu.pl

                                      tel3 +48 89 524 5101
                                      fax2 +48 89 524 5150
                      
                     

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