Enzyme-assisted extraction of fish oil from whole fish and by-products of Baltic herring (Clupea harengus membras)

Baltic herring (Clupea harengus membras) is one of the most abundant commercially caught fish species from the Baltic Sea. Despite the high content of fat and omega-3 fatty acids, the consumption of Baltic herring has decreased dramatically over the last four decades, mostly due to the small sizes and difficulty in processing. At the same time there is an increasing global demand for fish and fish oil rich in omega-3 fatty acids. This study aimed to investigate enzyme-assisted oil extraction as an environmentally friendly process for valorizing the underutilized fish species and by-products to high quality fish oil for human consumption. Three different commercially available proteolytic enzymes (Alcalase(R), Neutrase(R) and Protamex(R)) and two treatment times (35 and 70 min) were investigated in the extraction of fish oil from whole fish and by-products from filleting of Baltic herring. The oil quality and stability were studied with peroxide- and p-anisidine value analyses, fatty acid analysis with GC-FID, and volatile compounds with HS-SPME-GC-MS. Overall, longer extraction times led to better oil yields but also increased oxidation of the oil. For whole fish, the highest oil yields were from the 70-min extractions with Neutrase and Protamex. Protamex extraction with 35 min resulted in the best fatty acid composition with the highest content of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) but also increased oxidation compared to treatment with other enzymes. For by-products, the highest oil yield was obtained from the 70-min extraction with Protamex without significant differences in EPA and DHA contents among the oils extracted with different enzymes. Oxidation was lowest in the oil produced with 35-min treatment using Neutrase and Protamex. This study showed the potential of using proteolytic enzymes in the extraction of crude oil from Baltic herring and its by-products. However, further research is needed to optimize enzymatic processing of Baltic herring and its by-products to improve yield and quality of crude oil

Development and validation of a method for the analysis of halophenols and haloanisoles in cork bark macerates by stir bar sorptive extraction heart-cutting two-dimensional gas chromatography negative chemical ionization mass spectrometry

A method has been developed for the quantitative determination in cork bark macerates of 7halophenols and 5haloanisoles with demonstrated or suspected contribution to the cork taint off-flavour. Macerates were extracted with stirbar (20 mm polydimethylsiloxane-coated) sorptive extraction under optimized conditions (pH 3.5, 20% NaCl and 60 min). The bars were analysed byautomated thermal desorption, heart-cutting two-dimensional gas chromatography and negative chemical ionization-mass spectrometry. Matrix effects were compensated for by a “matrix matched” calibration curve. Limits of detection were in the range 0.03-0.24 ng L-1, below the corresponding odor thresholds. Linearity (0.983 = R2 = 0.998), intra- and inter-day precision (5.4-14.3%) and accuracy (89–126%) were satisfactory. The analysis of 48 natural cork bark samples affected/not-affected bya cryptogamic disease (yellow spot) revealed compositional differences in 2, 4, 6-trichloroanisole (2, 4, 6-TCA), 2, 4, 6-trichlorophenol (2, 4, 6-TCP) and also in 2, 6-dibromophenol, 2, 3, 4- and 2, 4, 5-TCP, 2, 3, 4-TCA and 2, 3, 4, 6-tetrachlorophenol (2, 3, 4, 6-TeCP). In addition, the contents of 2, 4, 6-TCP and 2, 4, 6-TCA, and 2, 3, 4, 6-TeCP and some TCPs presented strong linear correlations

Analysis of flavour compounds and prediction of sensory properties in sea buckthorn (Hippophae rhamnoides L.) berries

The aim of this study was to investigate sugars, organic acids, flavonol glycosides (FGs), proanthocyanidins and volatiles as flavour compounds in sea buckthorn (SB) berries of five cultivars and to predict the sensory properties of berries. The profiles of flavour compounds in SB berries varied significantly among the cultivars. Total proanthocyanidins and FGs were highest in 'Pertsik' and 'Raisa', respectively. Total volatiles were highest in 'Vorobyevskaya' and lowest in 'Raisa'. A previously established PLS model was used to predict the sensory properties of SB berries based on the non-volatile flavour compounds. The mouth-drying astringency can be predicted the most reliably, which has the highest regression coefficients with quinic acid, isorhamnetin-3-O-sophoroside-7-O-rhamnoside and total proanthocyanidins. Bitterness cannot be predicted using the model. 'Pertsik' berries were predicted to be more mouth-drying astringency and sour than those of 'Raisa'. The research supports the cultivar selection in cultivation and industry of SB berries

Profiles of Volatile Compounds in Blackcurrant (Ribes nigrum) Cultivars with a Special Focus on the Influence of Growth Latitude and Weather Conditions

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GC-MS-Olfactometric Differentiation of Aroma-Active Compounds in Turkish Heat-Treated Sausages by Application of Aroma Extract Dilution Analysis

Aroma and aroma-active compounds of the heat-treated Turkish sausages obtained from beef, turkey, and chicken meats were studied. Aroma compounds were isolated by using solvent-assisted flavor evaporation and analyzed by gas chromatography/mass spectrometry-olfactometry (GC-MS-O) for the first time. A total of 47, 63, and 64 aroma compounds, including esters, terpenes, terpenols, aldehydes, phenols, ketones, acids, alcohols, lactones, furans, sulfur compounds, and pyrazines, were identified and quantified in the beef, turkey, and chicken sausages, respectively. The most prominent differences between the sausage samples were as follows: (E)-sabinene hydrate, ß-cubebene, 2-hexanol, 5-methyl-2-heptanol, 2-heptanol, 2-nonanol, 4-methyl-3-hexanol, and heptanoic acid were detected only in chicken sausage samples; (Z)-p-mentha-1(7)8-dien-2-ol, dimethylallyl alcohol, 1,2-ethanediol, furfuryl alcohol, furfural, 2-ethyl-6-methylpyrazine, trimethyl pyrazine, and 2(5H)-furanone were detected only in turkey sausage samples; and 2-butoxyethanol, octanoic acid, and nonanoic acid were detected only in beef sausage samples. The aroma-active compounds of sausages were elucidated by using aroma extract dilution analysis (AEDA) for the first time. A combined total of 31 different aroma-active compounds were detected. The aroma-actives with the greatest flavor dilution (FD) factors in beef (FD 1024 and odor activity value (OAV) 178.07), and chicken (FD 2048 and OAV 262.63) sausages were ?-terpinene, and in turkey (FD 2048 and OAV 353.86) sausages were linalool. © 2018, Springer Science+Business Media, LLC, part of Springer Nature