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Kinetics of the Degradation of Anthocyanins, Phenolic Acids and Flavonols During Heat Treatments of Freeze-Dried Sour Cherry Marasca Paste

Zoran Zorić1*, Verica Dragović-Uzelac2, Sandra Pedisić1, Želimir Kurtanjek2 and
Ivona Elez Garofulić2

1
Faculty of Food Technology and Biotechnology, University of Zagreb, Petra Kasandrića 6,
HR-23000 Zadar, Croatia

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

Article history:

Received June 18, 2013

Accepted December 16, 2013

Key words:
anthocyanins, phenolic acids, flavonol glycoside, freeze-drying, thermal degradation,
sour cherry, Prunus cerasus var. Marasca

Summary:

The effect of heating temperature (80–120 °C) and processing time (5–50 min) on the
stability of anthocyanins (cyanidin-3-glucosylrutinoside, cyanidin-3-rutinoside and cyanidin-3-glucoside), quercetin-3-glucoside and phenolic acids (chlorogenic, neochlorogenic,p-coumaric and ferulic acids) in freeze-dried Marasca sour cherry pastes was studied. The degradation rates of individual anthocyanins, quercetin-3-glucoside and phenolic acids followed the first order reaction kinetics. Cyanidin-3-glucoside was found to be the most unstable among the anthocyanins, together with p-coumaric and neochlorogenic acids among other phenols. Activation energies for anthocyanin degradation ranged from 42 (cyanidin-3-glucosylrutinoside) to 55 kJ/mol (cyanidin-3-glucoside), and for other phenols from 8.12 (chlorogenic acid) to 27 kJ/mol (neochlorogenic acid). By increasing the temperature from 80 to 120 °C, the reaction rate constant of cyanidin-3-glucosylrutinoside increased from 2.2·10–2 to 8.5·10–2 min–1, of p-coumaric acid from 1.12·10–2 to 2.5·10–2 min–1 and of quercetin-3-glucoside from 1.5·10–2 to 2.6·10–2 min–1. The obtained results demonstrate that at 80°C the half-life of anthocyanins ranges from 32.10 min for cyanidin-3-glucosylrutinoside to 45.69 min for cyanidin-3-rutinoside, and of other phenolic compounds from 43.39 for neochlorogenic acid to 66.99 min for chlorogenic acid. The results show that the heating temperature and duration affect the anthocyanins considerably more than the other phenols in terms of degradation.

 

 

*Corresponding author:       zzoric@pbf.hr 
                                                        +385 23 331 077
                                           +385 23 331 089

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Modelling of Ethanol Production from Red Beet Juice by Saccharomyces cerevisiae under Thermal and Acid Stress Conditions

Donaji Jiménez-Islas
1, Jesús Páez-Lerma2, Nicolás Oscar Soto-Cruz2 and Jorge Gracida1,3*

1
Department of Biotechnology, Polytechnic University of Pachuca, Ex–Hacienda de Santa Bárbara,
Carretera Pachuca–Cd. Sahagún Km. 20, Zempoala, 43830 Hidalgo, Mexico

2Department of Chemical and Biochemical Engineering, Technological Institute of Durango, Blvd. Felipe Pescador 1830 Oriente, 34080 Durango, Mexico
3Department of Biotechnology, Autonomous University of Queretaro, Cerro de Las Campanas, 76010 Queretaro, Mexico

Article history:

Received December 5, 2012

Accepted January 16, 2014

Key words:
Beta vulgaris
L., modelling parameters, logistic, Pirt and Luedeking-Piret equations

Summary:

In this work the effects of pH and temperature on ethanol production from red beet
juice by the strains Saccharomyces cerevisiae ITD00196 and S. cerevisiae ATCC 9763 are studied. Logistic, Pirt, and Luedeking-Piret equations were used to describe quantitatively the microbial growth, substrate consumption, and ethanol production, respectively. The two S.cerevisiae strains used in this study were able to produce ethanol with high yield and volumetric productivity under acid and thermal stress conditions. The equations used to model the fermentation kinetics fit very well with the experimental data, thus establishing that ethanol production was growth-associated under the evaluated conditions. The yeast S. cerevisiae ITD00196 had the best fermentative capacity and could be considered as an interesting option to develop bioprocesses for ethanol production.

 

 

*Corresponding author:       
                                                    
     +52 442 192 1200, Ext. 5557

                                            +52 442 192 1200, Ext. 5570

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Thermodynamic Properties, Sorption Isotherms and Glass Transition Temperature of Cape Gooseberry (Physalis peruviana L.)

Antonio Vega-Gálvez1, Jessica López1, Kong Ah-Hen2*, María José Torres1 and Roberto Lemus-Mondaca1

1
Food Engineering Department, La Serena University, Raúl Bitrán Avenue, La Serena,
Region of Coquimbo, Chile

2Institute of Food Science and Technology, Austral University of Chile, Julio Sarrazín Avenue, Valdivia, Region de los Ríos, Chile

Article history:

Received March 26, 2013
Accepted October 1, 2013

Key words:

Cape gooseberry, sorption isotherm, modelling, isosteric heat, glass transition temperature, Gordon-Taylor model

Summary:

Adsorption and desorption isotherms of fresh and dried Cape gooseberry (Physalis peruviana L.) were determined at three temperatures (20, 40 and 60 ºC) using a gravimetric technique. The data obtained were fitted to several models including Guggenheim-Anderson-De Boer (GAB), Brunauer-Emmett-Teller (BET), Henderson, Caurie, Smith, Oswin, Halsey and Iglesias-Chirife. A non-linear least square regression analysis was used to evaluate the models. The Iglesias-Chirife model fitted best the experimental data. Isosteric heat of sorption was also determined from the equilibrium sorption data using the Clausius-Clapeyron equation and was found to decrease exponentially with increasing moisture content. The enthalpy-entropy compensation theory was applied to the sorption isotherms and indicated an enthalpy-controlled sorption process. Glass transition temperature (Tg) of Cape gooseberry was also determined by differential scanning calorimetry and modelled as a function of moisture content with the Gordon-Taylor, the Roos and the Khalloufi models, which proved to be excellent tools for predicting glass transition of Cape gooseberry.


 

*Corresponding author:      kshun@uach.cl   
                                                   +56 63 221 302
                                          
+56 63 221 355

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Screening for Extracellular Lipase Enzymes with Transesterification Capacity in Mucoromycotina Strains

Alexandra Kotogán, Brigitta Németh, Csaba Vágvölgyi, Tamás Papp and Miklós Takó*


Department of Microbiology, Faculty of Science and Informatics, University of Szeged,
Közép fasor 52, HU-6726 Szeged, Hungary

Article history:

Received June 3, 2013

Accepted January 30, 2014

Key words:

zygomycetes, tributyrin, wheat bran, p-nitrophenyl palmitate, transesterification

Summary:

In this study, 169 zygomycetes fungal strains including some cold-tolerant isolates
were screened for their extracellular lipolytic activity towards tributyrin. Nineteen of them were outstanding in their enzyme production as they developed the largest lipolytic halo around the colonies in plate tests. Mortierella alpina, M. echinosphaera, Mucor corticolus, Rhizomucor miehei, Rhizopus oryzae, Rh. stolonifer, Umbelopsis autotrophica, U. isabellina, U. ramanniana var. angulispora and U. versiformis were selected for further studies to characterise their lipolytic enzyme production in detail. In these assays, effect of Tween 80 and palm, soybean, sunflower, olive, extra virgin olive, wheat germ, corn germ, sesame seed, pumpkin seed and cottonseed oils on the enzyme activities was investigated, and wheat bran-based submerged and solid-state fermentations were also tested. Tween 80 and olive oil proved to be efficient inductors for lipolytic enzyme production, which was also enhanced when wheat bran was used as support. Addition of mineral salts and olive oil to the solid fermentation medium resulted in at least 1.5-fold increment in the enzyme activities of the crude extracts. Organic synthesis was also assayed by the selected lipases, in which enzymes from the fungi R. miehei, Rh. stolonifer and M. echinosphaera gave the best yields during transesterification reactions between p-nitrophenyl palmitate and ethanol.

 

 

*Corresponding author:        tako78@bio.u-szeged.hu
                                                          +36 62 544 516

                                            +36 62 544 823

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