https://doi.org/10.17113/ftb.53.01.15.3533

Ultrasound-Assisted Extraction and Biological Activities of Extracts of Brassica oleracea var.
capitata

Valéria Dal Prá¹, Carolina Bolssoni Dolwitsch¹, Fernanda Oliveira Lima², Camilo Amaro de Carvalho³, Carine Viana¹,
Paulo Cícero do Nascimento⁴ and Marcelo Barcellos da Rosa^1,4*

¹Post-Graduate Program in Pharmaceutical Sciences, Federal University of Santa Maria, Camobi Campus, 97105-900 Santa
  Maria, RS, Brazil
²Federal University of Fronteira Sul, Centro, 97900-000 Cerro Largo, RS, Brazil
³Medical and Nursing Department, Federal University of Viçosa, Av. Peter Henry Rolfs, s/n, 36570-000 Viçosa, Brazil
⁴Post-Graduate Program in Chemistry, Federal University of Santa Maria, Camobi Campus, 97105-900 Santa Maria, RS, Brazil



Article history:
Received October 4, 2013
Accepted January 26, 2015



Key words:
Brassica oleracea var. capitata, ultrasound-assisted extraction, hydrolysis of extracts, biological activity

Summary:
In this work, the antioxidant and antimicrobial activities of Brassica oleracea var. capitata extracts obtained through ultrasound-assisted extraction are evaluated. The extracts obtained using the best extraction conditions were subjected to different hydrolysis conditions before their use in the biological tests. The crude and hydrolysed extracts were characterized using gas chromatography coupled with a mass detector. The use of ultrasound at 30 °C with 60 % (by volume) solvent enabled obtaining a richer extract. All extracts had antioxidant activities against DPPH (13.0–80.0 %), superoxide (35.2–63.2 %) and peroxyl (89.3–99.5 %) radicals, but the use of hydrolysed extracts considerably improved the antioxidant activities. Antimicrobial activities only of the hydrolysed extracts of Brassica oleracea var. capitata were detected. It was confirmed that antioxidant activity of vegetable extracts can be considerably increased when hydrolysis is applied as a pretreatment to their extraction.

*Corresponding author:     marcelobdarosa@gmail.com  
                                        +55 55 3220 8870

     https://doi.org/10.17113/ftb.53.01.15.3740

Efficient Degumming of Rice Bran Oil by Immobilized PLA₁ from Thermomyces lanuginosus

Tripti Singhania, Harsh Sinha, Paulomi Das and Amit Kumar Mukherjee*

Department of Food Technology, Haldia Institute of Technology, P. O. HIT, Hatiberia, Purba Medinipur, 721657 Haldia,
West Bengal, India



Article history:
Received May 24, 2014
Accepted January 19, 2015



Key words:
phospholipase A₁, Thermomyces lanuginosus, phospholipids, degumming, rice bran oil, immobilization

Summary:
Phospholipase A₁ (PLA₁) immobilized in calcium alginate can effectively overcome the mass transfer resistance at the lipid-water interface making more room for the enzyme to separate itself from the products of reaction and to bind with the next available molecule at the interface. The reaction of an immobilized PLA₁ hydrolase from Thermomyces lanuginosus was comparatively faster than of its free form. The rate of phospholipid hydrolysis by PLA₁ was studied in calcium-rich and calcium-depleted environments; and the extent of phosphorus removed from the crude rice bran oil as well as the amount of free fatty acids produced during the reaction were used as indices for analysing the rate of enzymatic hydrolysis under standard conditions of pH, temperature, time of incubation and agitation. The immobilized PLA₁ was found to be superior in removing phosphorus in the presence of 10 mM bivalent calcium ions in a solution. As compared to a maximum of 72.52 % phosphorus removed by 0.01 kg of free enzyme per kg of oil, the same amount of immobilized PLA₁ removed phosphorus from oil by 94.12 % under the same experimental conditions (pH=6, 60 °C, 1-hour incubation). Both the free PLA₁ and its immobilized form had shown extended rates of hydrolysis in a calcium-rich environment. The mass fractions of free fatty acids produced by the free enzyme and by its immobilized form were 14.9 and 14.16 %, respectively, under the above experimental conditions. The removal of phosphorus from oil was accompanied by a significant reduction in colour and restoration of iodine value to the desired level.

*Corresponding author:     mukherjee2001@gmail.com   
                                         +91 9477 290 235 
                                         +91 3224 252 800/253 062

    https://doi.org/10.17113/ftb.53.01.15.3617

Effect of Ethanol Stress on Fermentation Performance of Saccharomyces cerevisiae Cells
Immobilized on Nypa fruticans Leaf Sheath Pieces

Hoang Phong Nguyen, Hoang Du Le and Van Viet Man Le*

Department of Food Technology, Ho Chi Minh City University of Technology, 268 Ly Thuong Kiet Street, District 10,
70000 Ho Chi Minh City, Vietnam



Article history:
Received February 16, 2014
Accepted November 7, 2014



Key words:
Saccharomyces cerevisiae, immobilized yeast, ethanol stress, Nypa fruticans, fatty acids




Summary:
The yeast cells of Saccharomyces cerevisiae immobilized on Nypa fruticans leaf sheath pieces were tested for ethanol tolerance (0, 23.7, 47.4, 71.0 and 94.7 g/L). Increase in the initial ethanol concentration from 23.7 to 94.7 g/L decreased the average growth rate and concentration of ethanol produced by the immobilized yeast by 5.2 and 4.1 times, respectively. However, in the medium with initial ethanol concentration of 94.7 g/L, the average growth rate, glucose uptake rate and ethanol formation rate of the immobilized yeast were 3.7, 2.5 and 3.5 times, respectively, higher than those of the free yeast. The ethanol stress inhibited ethanol formation by Saccharomyces cerevisiae cells and the yeast responded to the stress by changing the fatty acid composition of cellular membrane. The adsorption of yeast cells on Nypa fruticans leaf sheath pieces of the growth medium increased the saturated fatty acid (C16:0 and C18:0) mass fraction in the cellular membrane and that improved alcoholic fermentation performance of the immobilized yeast.

*Corresponding author:     lvvman@hcmut.edu.vn  
                                         +84 8 3864 6251 
                                         +84 8 3863 7504

    https://doi.org/10.17113/ftb.53.01.15.3893  

Proteolysis of Sardine (Sardina pilchardus) and Anchovy (Stolephorus commersonii)
by Commercial Enzymes in Saline Solutions

Chau Minh Le^1,2, Claire Donnay-Moreno², Sandrine Bruzac², Régis Baron², Huong Thi My Nguyen³ and Jean
Pascal Bergé⁴*

¹College of Agriculture and Forestry, Thai Nguyen University, Quyet Thang, Thai Nguyen, Vietnam
²IFREMER, rue de l’île d’Yeu, BP 21105, FR-44311 Nantes, France
³Nha Trang University, 2 Nguyen Dinh Chieu, Nha Trang, Vietnam
⁴IDMER, 2 rue Batelière, FR-56100 Lorient, France


Article history:
Received September 9, 2014
Accepted January 8, 2015



Key words:
hydrolysis, proteases, salt, sardine, anchovy, fish sauce




Summary:
Fish sauce production is a very long process and there is a great interest in shortening it. Among the different strategies to speed up this process, the addition of external proteases could be a solution. This study focuses on the effect of two commercial enzymes (Protamex and Protex 51FP) on the proteolysis of two fish species traditionally converted into fish sauce: sardine and anchovy, by comparison with classical autolysis. Hydrolysis reactions were conducted with fresh fish at a temperature of 30 °C and under different saline conditions (from 0 to 30 % NaCl). Hydrolysis degree and liquefaction of the raw material were used to follow the process. As expected, the proteolysis decreased with increasing amount of salt. Regarding the fish species, higher rate of liquefaction and higher hydrolysis degree were obtained with anchovy. Between the two proteases, Protex 51FP gave better results with both fish types. This study demonstrates that the addition of commercial proteases could be helpful for the liquefaction of fish and cleavage of peptide bonds that occur during fish sauce production and thus speed up the production process.

*Corresponding author:     jpberge@idmer.com   
                                         +33 297 838 683
                                         +33 240 374 071