Recent Advances in Astaxanthin Micro/Nanoencapsulation to Improve Its Stability and Functionality as a Food Ingredient.

Astaxanthin is a carotenoid produced by different organisms and microorganisms such as microalgae, bacteria, yeasts, protists, and plants, and it is also accumulated in aquatic animals such as fish and crustaceans. Astaxanthin and astaxanthin-containing lipid extracts obtained from these sources present an intense red color and a remarkable antioxidant activity, providing great potential to be employed as food ingredients with both technological and bioactive functions. However, their use is hindered by: their instability in the presence of high temperatures, acidic pH, oxygen or light; their low water solubility, bioaccessibility and bioavailability; their intense odor/flavor. The present paper reviews recent advances in the micro/nanoencapsulation of astaxanthin and astaxanthin-containing lipid extracts, developed to improve their stability, bioactivity and technological functionality for use as food ingredients. The use of diverse micro/nanoencapsulation techniques using wall materials of a different nature to improve water solubility and dispersibility in foods, masking undesirable odor and flavor, is firstly discussed, followed by a discussion of the importance of the encapsulation to retard astaxanthin release, protecting it from degradation in the gastrointestinal tract. The nanoencapsulation of astaxanthin to improve its bioaccessibility, bioavailability and bioactivity is further reviewed. Finally, the main limitations and future trends on the topic are discussed.

A quick method for identifying radiolytic hydrocarbons in low-fat-containing food.

BACKGROUND: As radiation-induced alterations of the lipid fraction of foods are related to their initial fat content, concentrations of fat degradation products used as irradiation markers are expected to be lower when irradiating low-fat-containing foods. Thus the sensitivity required when applying analytical methods for identifying irradiation markers in foods eventually depends on their respective amounts of fat. The aim of this study was to perform the qualitative analysis of characteristic hydrocarbons resulting from irradiation of samples with a fat content as low as 25 g kg(-1). RESULTS: A rapid extraction using a small amount of ethyl acetate was the unique sample pretreatment required to accomplish the analysis of radiolytic markers by using on-line coupling of reverse phase liquid chromatography and gas chromatography with mass spectrometry detection (RPLC/GC/MS). Efficient elimination of the large volumes (up to 2170 µL) directly transferred from LC to GC was achieved by optimising the operation mode of the through-oven transfer adsorption/desorption system used as interface. CONCLUSION: The reported procedure allowed confirmation, in less than 65 min, of the occurrence of up to five irradiation markers, namely n-pentadecane, 1-hexadecene, 1,7-hexadecadiene, n-heptadecane and 8-heptadecene, in cooked ham irradiated at doses as low as 2 kGy.

Chiral analysis by online coupling of reversed-phase liquid chromatography to gas chromatography and mass spectrometry.

Enantiomeric composition of selected chiral compounds present in complex mixtures is determined by using the online coupling of reversed-phase liquid chromatography (LC) to gas chromatography (GC) and mass spectrometry. Integration of sample preparation into GC analysis, in a completely automated way, is achieved by means of the effective clean-up resulting from both the LC fractionation step and the eluent elimination provided by the through oven transfer adsorption desorption system used for LC-GC interfacing. The possibilities of the technique are illustrated through some examples concerning the stereodifferentiation in essential oils of major and minor chiral compounds via LC-GC transfer of different volume fractions, ranging from 0.5 to 1.9 ml, which show the significance of the window size for the determination of enantiomeric profiles.

1H-HRMAS NMR study of smoked Atlantic salmon (Salmo salar).

High-resolution magic angle spinning (HRMAS) NMR spectroscopic data of smoked Atlantic salmon (Salmo salar) were fully assigned by combination of one- and two-dimensional-HRMAS experiments. Complete representative spectra, obtained after few minutes of analysis time, revealed a large number of minor and major compounds in the sample. The methodology is limited by the low sensitivity of NMR, and therefore HRMAS only enables the determination of the most relevant components. These were fatty acids (FAs), carbohydrates, nucleoside derivatives, osmolytes, amino acids, dipeptides and organic acids. For the first time, spectra were resolved sufficiently to allow semiquantitative determination in intact muscle of the highly polyunsaturated FA 22:6 omega-3. Additionally, the feasibility of (1)H-HRMAS NMR metabolite profiling was tested to identify some bioactive compounds during storage. This profiling was carried out by the non-destructive and direct analysis (i.e. without requiring sample preparation and multiple step procedures) of intact salmon muscle. The proposed procedure can be applied to a large number of samples with high throughput due to the short time of analysis and quick evaluation of the data.

Beef hamburgers enriched in lycopene using dry tomato peel as an ingredient.

The direct addition of dry tomato peel (DTP) to hamburgers may be useful both to obtain a new product enriched in lycopene and for providing a use for this by-product from the tomato industry. In this study, different amounts of DTP (0-6.0%w/w) were added to raw and cooked hamburgers, and the effects on the meat's physico-chemical and sensorial characteristics were studied. The maximum DTP concentration compatible with good sensory acceptability and high lycopene content was determined. Addition of DTP increased the colour parameters a(∗) and b(∗) of raw and cooked hamburgers, and modified all textural properties probably because of the presence of fibre. The hardness values of cooked samples was significantly higher in the batch containing 6% DTP (67.6N) than in a control batch (50.9N, p<0.05). The addition of DTP to 4.5% results in hamburgers with good overall acceptability and a lycopene content of 4.9mg/100g of cooked hamburger.

Effect of E-beam treatment on the chemistry and on the antioxidant activity of lycopene from dry tomato peel and tomato powder.

Tomato powder (TP) and dry tomato peel (DTP) have been previously used in our laboratory as a source of lycopene to manufacture meat products ready-to-eat (RTE) submitted to E-beam irradiation with good technological and sensory results. Present work describes the studies performed in order to investigate the effect of radiation on chemical changes and antioxidant properties of lycopene. DTP and TP were irradiated (4 kGy). Changes on lycopene were analyzed by HPLC; inhibition of reactive oxygen species (ROS), possible modulation of mitogen-activated protein kinases (MAPK) cascade, nuclear factor κ-light-chain-enhancer of activated B cells (NP-κB) activation and expression of proteins involved in oxidation stress were analyzed in RAT-1 fibroblasts cell culture. Radiation reduced the content of all-E-lycopene and increased (Z)-lycopene, lycopene isomerization, and degradation being higher in DTP than in TP. E-Beam treatment increased the antioxidant ability of both DTP and TP in inhibiting spontaneous and H2O2-induced oxidative stress in cultured fibroblasts. Antioxidant activity was higher in DTP than in TP samples.

Analysis of irradiated cooked ham by direct introduction into the programmable temperature vaporizer of a multidimensional gas chromatography system.

A simple method involving direct introduction (DI) of cooked ham into a programmable temperature vaporizer and subsequent thermal desorption for multidimensional chromatographic analysis as a tool for studying changes of volatile compounds during food irradiation has been proposed. Analysis of non-irradiated samples showed four peaks in the precolumn, which were identified on the main column as peak 1, ethyl acetate; peak 2, a mixture of octanol and ethyl propanoate; peak 3, (R,R)-2,3-butanediol, and peak 4, nonanoic acid. (R,R) and (S,S)-2,3-butanediol were detected in samples irradiated at 8 kGy, which may indicate that irradiation induces isomerisation. When a single cut was transferred from the precolumn to the main column, 1-tetradecene, n-pentadecane, 8-heptadecene and 1-hexadecene were detected in irradiated samples. This simple and easy method allows detection of radiolytic markers and isomerisation of 2,3-butanediol during irradiation of food.

Enantiomeric analysis of chiral compounds in irradiated foods using multidimensional gas chromatography.

The usefulness of both solid phase microextraction (SPME) and multidimensional gas chromatography (MDGC) coupled to mass spectrometry (MS) to detect chiral compounds in irradiated cheese was evaluated. The enantiomeric resolution of relevant chiral aroma compound was achieved by analyzing the extracts obtained from SPME by means of a permethylated beta-CD stationary phase as the main column of the multidimensional system to separate specific selected cuts containing components unresolved in the first dimension. The proposed procedure allowed to determine, in less than 90 min, that no significant variations had been produced in the stereoisomeric distribution of limonene, 3-hydroxybutanone, and 2,3-butanediol in cheese when applying irradiation doses ranging from 0 to 8 kGy.

Rennet - Clotting Properties and Starter Activity on Milk Acidified with Carbon Dioxide.

The influence of acidification with CO2 on starter activity, rennet clotting properties, and cheese yield have been studied. Results obtained with lactic acid-treated milk were compared with those obtained with CO2-treated milks. CO2-treated samples showed lower acidification by starter than lactic acid-treated samples. The higher final pH values found in CO2-treated samples could be attributed to reduced starter metabolic activity. Heat treatments to 60 or 70°C for 30 min did not influence coagulation time by rennet. Acidification produced a decrease of coagulation time, which was more pronounced on samples treated with lactic acid. Cheese yield was influenced by the growth of psychrotrophic bacteria during storage of milk.

Correlation between Lactulose and Furosine in UHT-Heated Milk.

The kinetics of furosine and lactulose formation during heat treatment of milk and correlations between these parameters have been studied as a contribution for setting legal standards for heat-processed milks. Activation energies of 93.15 ± 5.87 kJ/mol and 153.2 ± 6.49 kJ/mol for furosine and lactulose respectively were computed from zero-order rate constants. Polynomial and logarithmic equations were developed to predict the furosine content as a function of lactulose content. The polynomial equation proposed fit the experimental data and previously reported data. The standard error of the prediction was lower than ±7.8mg/liter. The application of this equation to observed values for lactulose and furosine in commercial milk samples would allow the detection of milk powder in UHT milk.