Highlights of the 3rd International Conference on High Pressure Bioscience and Biotechnology

The 3rd International Conference on High Pressure Bioscience and Biotechnology was held in the city of Rio de Janeiro from September 27 to September 30, 2004. The meeting, promoted by the International Association of High Pressure Bioscience and Biotechnology (IAHPBB), congregated top scientists and researchers from all over the world. In common, they shared the use of hydrostatic pressure for research, technical development, or industrial applications. The meeting consisted of invited lectures, contributed papers and a well-attended poster session. Very exciting discussions were held inside and outside the sessions, and the goals of discussing state-of-the-art data and establishing working collaborations and co-operations were fully attained.

The biological effects of high-pressure gas on the yeast transcriptome

The aim of the present study was to examine the feasibility of DNA microarray technology in an attempt to construct an evaluation system for determining gas toxicity using high-pressure conditions, as it is well known that pressure increases the concentration of a gas. As a first step, we used yeast (Saccharomyces cerevisiae) as the indicator organism and analyzed the mRNA expression profiles after exposure of yeast cells to nitrogen gas. Nitrogen gas was selected as a negative control since this gas has low toxicity. Yeast DNA microarray analysis revealed induction of genes whose products were localized to the membranes, and of genes that are involved in or contribute to energy production. Furthermore, we found that nitrogen gas significantly affected the transport system in the cells. Interestingly, nitrogen gas also resulted in induction of cold-shock responsive genes. These results suggest the possibility of applying yeast DNA microarray to gas bioassays up to 40 MPa. We therefore think that "bioassays" are ideal for use in environmental control and protection studies.

HIGH PRESSURE VAPOR-LIQUID EQUILIBRIA OF PALM FATTY ACIDS DISTILLATES-CARBON DIOXIDE SYSTEM

Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid) and unsaturated (oleic+linoleic acids) fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.

THE GENERALIZED MAXIMUM LIKELIHOOD METHOD APPLIED TO HIGH PRESSURE PHASE EQUILIBRIUM

The generalized maximum likelihood method was used to determine binary interaction parameters between carbon dioxide and components of orange essential oil. Vapor-liquid equilibrium was modeled with Peng-Robinson and Soave-Redlich-Kwong equations, using a methodology proposed in 1979 by Asselineau, Bogdanic and Vidal. Experimental vapor-liquid equilibrium data on binary mixtures formed with carbon dioxide and compounds usually found in orange essential oil were used to test the model. These systems were chosen to demonstrate that the maximum likelihood method produces binary interaction parameters for cubic equations of state capable of satisfactorily describing phase equilibrium, even for a binary such as ethanol/CO2. Results corroborate that the Peng-Robinson, as well as the Soave-Redlich-Kwong, equation can be used to describe phase equilibrium for the following systems: components of essential oil of orange/CO2.

HIGH PRESSURE PHASE EQUILIBRIUM: PREDICTION OF ESSENTIAL OIL SOLUBILITY

This work describes a method to predict the solubility of essential oils in supercritical carbon dioxide. The method is based on the formulation proposed in 1979 by Asselineau, Bogdanic and Vidal. The Peng-Robinson and Soave-Redlich-Kwong cubic equations of state were used with the van der Waals mixing rules with two interaction parameters. Method validation was accomplished calculating orange essential oil solubility in pressurized carbon dioxide. The solubility of orange essential oil in carbon dioxide calculated at 308.15 K for pressures of 50 to 70 bar varied from 1.7± 0.1 to 3.6± 0.1 mg/g. For same the range of conditions, experimental solubility varied from 1.7± 0.1 to 3.6± 0.1 mg/g. Predicted values were not very sensitive to initial oil composition.

Ochratoxin A determination in beer by immunoaffinity column clean-up and high-performance liquid chromatography

Analyses of ochratoxin A (OTA) in domestic and imported beers were perfomed by immunoaffinity column and high - perfomance liquid chromatography (HPLC) using a fluorescence detector. Recoveries of OTA from beer samples spiked at levels from 8.0 to 800pg/mL ranged from 81.2% to 95.0%, with coefficient of variation between 0% e 11.0%. Detection limit and quantification limit were 2.0pg/mL and 8.0pg/mL, respectively. Of the total of 26 samples produced in Brazil only 6 (23%), contained trace amounts of OTA. Of the 4 imported beers, in 2, Ireland and Germany, were detected OTA at levels of 25pg/mL and 82pg/mL, respectively.

Preparation of powdered egg yolk using a mini spray dryer

Powdered egg is used as an emulsifying agent in emulsion formulations. It is an excellent source of high quality protein, of which the yolk contains 44% and the egg white 56%. Spray drying is a widely applied method for drying aqueous or organic solutions and emulsions in the chemical and food industries. Spray drying can be used to preserve food or simply as a rapid drying method. The objective of this work was to study the viability of obtaining powdered egg yolk powder using a Büchi B-190 Mini Spray Dryer. The egg yolk protein was evaluated by the semi-micro Kjeldahl method. It was concluded that the use of the Büchi B-190 Mini Spray Dryer to produce powdered egg yolk is perfectly feasible.

Biotechnological production of bioflavors and functional sugars

Bioflavors and oligosaccharides are two classes of substances that may be produced biotechnologically through microbial bioprocesses. These compounds have attracted the interest of pharmaceutical and food industries not only due to their technological properties (sweetening/fiber or flavoring, respectively), but also as a consequence of other functional properties such as, for example, health promoting benefits. The use of agro-industrial residues as substrates in biotechnological processes seems to be a valuable alternative in helping to overcome the high manufacturing costs of industrial fermentations. This manuscript reviews the most important advances in biotechnological production of bioflavors and oligosaccharides. The use of some agro-industrial residues in such processes is also cited and discussed, showing that this is a rising trend in biotechnology.

β-carotene biotransformation to obtain aroma compounds

Carotenoids are important constituents of food due to their color and because their degradation products generate important volatile compounds in foods. Aroma compounds derived from carotenoids are widely distributed in nature, and they are precursors of many important aromas in foods such as fruits and in flowers as well. They present high aromatic potential and are therefore of great interest to the industries of aromas and fragrances. In this study, more than 300 previously isolated microorganisms with potential for biotransformation of β-carotene present in the culture medium were selected using the plate method; about 80 strains presented capacity to produce aroma compounds and 7 strains were selected by an untrained panel of tasters to generate aroma compounds. The β-ionone was the main compound produced by CS1 (34.0 mg.L-1) and CF9 (42.4 mg.L-1) microorganisms at 72 and 24 hours of fermentation, cultured with and without pre-inoculation, respectively. The β-damascone and pseudoionone were found in low concentrations, 1,1,6-trimethyl-1,2,3,4-tetrahydronaphthalen (TTN) was tentatively identified and other compounds such as apocarotenoids, apparently obtained from the cleavage of the central part of the carotenoid, were detected.

Quality of Canned mandarin as affected by preservation liquid

This study is integrated within a research line dedicated to evaluate different options to introduce mandarin in Spanish agro-food industries and in both national and international markets. The effects of different preservation liquids (sucrose solution, sucrose and ascorbic acid solution, grape, and grapefruit juices), soluble solids (10, 12, 14 ºBrix), and thermal processing (30 seconds at 98 ºC) on vitamin C, color, carotenoids and sensory quality of canned Satsuma mandarin segments were studied. The liquid preservation that presented the best results was grapefruit juice, which provided the highest vitamin C (323 mg.L-1) and total carotenoids (16.4 mg.L-1) contents (the main carotenoid found was β-cryptoxanthin), intense orange color, high thermal stability, and very good sensory quality (e.g. intense floral and fresh-mandarin aromas and low levels of off-flavors).

Characterization of a high oleic oil extracted from papaya (Carica papaya L.) seeds

The physicochemical characteristics, fatty acid, tocopherol, and carotenoid composition of a crude oil extracted from papaya (Carica papaya L.) seeds, formosa variety, were investigated. The oil yield from the seeds was 29.16%. The data obtained for the analytical indexes were in agreement with those of other edible oils. The oil obtained had high oxidation resistance (77.97 hours). The major fatty acids in total lipid were oleic (71.30%), palmitic (16.16%), linoleic (6.06%), and stearic (4.73%) acid. The α and δ-tocopherol were the predominant tocopherols with 51.85 and 18.89 mg.kg-1, respectivelly. The β-cryptoxanthin (4.29 mg.kg-1) and β-carotene (2.76 mg.kg-1) were the carotenoids quantified, and the content of total phenolic compounds was 957.60 mg.kg-1. Therefore, the potential utilization of the papaya seeds for oil production seems favorable. However, toxicological studies need to be carried out before the oil is appropriate for food applications.

Effects of heat treatment and storage temperature on the use of açaí drink by nutraceutical and beverage industries

This study assesses the storage temperature effect on the anthocyanins of pasteurized and unpasteurized açaí pulp. The data was obtained using a pasteurized and lyophilized pulp (PLP) to evaluate the temperature effect (0, 25, and 40 °C). Part of non-pasteurized frozen pulp (NPP) was pasteurized (NPP-P) at 90 °C for 30 seconds; both pulps were stored at 40 °C. The anthocyanin content reduction in the drink was evaluated from the half-life time (t1/2), activation energy (Ea), temperature quotient (Q10), and the reaction rate constant (k). The t1/2 of the PLP anthocyanins stored at 40 °C was 1.8 times less than that stored at 25 °C and 15 times less than that stored at 0 °C; therefore, the higher temperatures decreased the stability of anthocyanins. The pasteurization increased the t1/2 by 6.6 times (10.14 hours for NPP and 67.28 hours for NPP-P). The anthocyanin degradation on NPP-P followed a first order kinetic, while NPP followed a second order kinetic; thus it can be said that the pasteurization process can improve the preservation of anthocyanins in the pulp.

Chemical and physical properties of aloe vera (Aloe barbadensis Miller) gel stored after high hydrostatic pressure processing

The aim of this study was to evaluate the influence of high hydrostatic pressure (150, 250, 350, 450, and 550 MPa), applied for 5 minutes, on antioxidant capacity, total phenolic content, color, firmness, rehydration ratio, and water holding capacity of aloe vera gel stored for 60 days at 4 °C. The analyzed properties of the pressurized gel showed significant changes after the storage period. The highest value of total phenolic content was found at 550 MPa. However, a decrease in the antioxidant capacity was observed for all pressurized gel samples when compared to the control sample (p < 0.05). The smallest changes in product color were observed at pressure levels between 150 and 250 MP. The application of high hydrostatic pressure resulted in lower gel firmness, and the lowest value was found at 150 MPa (p < 0.05). On the other hand, the untreated sample showed a greater decrease in firmness, indicating that high pressure processing preserves this property. The application of high hydrostatic pressure exhibited modifications in the food matrix, which were evaluated in terms of rehydration ratio and water holding capacity.

Hygienic-sanitary working practices and implementation of a Hazard Analysis and Critical Control Point (HACCP) plan in lobster processing industries

This study aimed to verify the hygienic-sanitary working practices and to create and implement a Hazard Analysis Critical Control Point (HACCP) in two lobster processing industries in Pernambuco State, Brazil. The industries studied process frozen whole lobsters, frozen whole cooked lobsters, and frozen lobster tails for exportation. The application of the hygienic-sanitary checklist in the industries analyzed achieved conformity rates over 96% to the aspects evaluated. The use of the Hazard Analysis Critical Control Point (HACCP) plan resulted in the detection of two critical control points (CCPs) including the receiving and classification steps in the processing of frozen lobster and frozen lobster tails, and an additional critical control point (CCP) was detected during the cooking step of processing of the whole frozen cooked lobster. The proper implementation of the Hazard Analysis Critical Control Point (HACCP) plan in the lobster processing industries studied proved to be the safest and most cost-effective method to monitor each critical control point (CCP) hazards.

Antioxidant potential of barley extract in rats subjected to a high-fat diet

Antioxidants have the ability to neutralize free radicals produced in the body during lipid oxidation. The objective in this article was to study the effect of the barley extract on lipid oxidation in rats subjected to a high-fat diet. The experiment lasted 67 days. The animals were separated into three experimental groups: standard (P), high-fat diet group (L), and group with high-fat diet supplemented with barley extract (C). The feed intake of L and C groups was the lowest (p < 0.05). The treatments did not influence weight gain, organ weight, and the blood parameters measured. However, the levels of malondialdehyde present in the liver tissue were higher in the L group and lower in the P and C groups. Therefore, the results indicated an increased level of lipid peroxidation in the liver of rats subjected to high-fat diet, which was reduced by the consumption of barley.