Rapid method for controlling the correct labeling of products containing common octopus (Octopus vulgaris) and main substitute species (Eledone cirrhosa and Dosidicus gigas) by fast real-time PCR

The TaqMan real-time PCR has the highest potential for automation, therefore representing the currently most suitable method for screening, allowing the detection of fraudulent or unintentional mislabeling of species. This work describes the development of a real-time polymerase chain reaction (RT-PCR) system for the detection and identification of common octopus (Octopus vulgaris) and main substitute species (Eledone cirrhosa and Dosidicus gigas). This technique is notable for the combination of simplicity, speed, sensitivity and specificity in an homogeneous assay.     

Antioxidant activity, ascorbic acid, phenolic compounds and sugars of wild and commercial Tuberaria lignosa samples: Effects of drying and oral preparation methods

The antioxidant activity and phytochemical composition (ascorbic acid, free sugars and phenolic compounds) of decoctions and infusions of wild and commercial samples of Tuberaria lignosa (Sweet) Samp. Aerial parts were evaluated and compared. Among wild samples, the effects of the drying method (freeze or shade-drying) on those parameters were studied. Infusion of the freeze-dried wild sample gave the highest levels of sugars, while infusion of shade-dried wild sample and decoction of the freeze-dried sample presented higher ascorbic acid and phenolic compounds content (including ellagitannins and flavonoids) than the other samples. The last two samples also revealed higher antioxidant activity, in some cases even higher than Trolox. Decoctions gave lower amounts of disaccharides than infusions, which seemed to be hydrolysed, increasing the content of monosaccharides. Commercial samples showed the lowest content in phenolic compounds, mainly in ellagitannins and flavonoids, and also the lowest antioxidant activity. This work gives scientific evidence to the traditional medicinal uses of wild Tuberaria lignosa, highlighting the interest of its decoctions and infusions as a source of bioactive compounds and functional beverages.     

Effects of commercial canning on SDS-PAGE patterns of the albumin fraction of four pea sizes

Size has been related with pea seed growth and maturation [1], and it is also considered an important parameter when peas are chosen for canning [2]. Some changes occur in the composition of vegetables during blanching, which are the partial loss of major components [3], that are further reduced during canning, mainly due to leaching into the water used for processing [4]. This leaching can be significant if the brine is discarded and not used as a part of the food consumed, as it is often done with most of canned vegetables [5]. Pea seed is an important source of protein for humans, and it has been suggested [6] that when considering pea seeds protein quality more emphasis should be given to the study of the albumin fraction, because it is the fraction rich in the sulphur amino acids. Although electrophoretic analysis of heat-treated proteins can be considered as time consuming it has been used to monitor changes in specific proteins and mixtures of protein subjected to a variety of heat treatments [7]. In general, heat treatments result in a drastic change in polyacrylamide gel electrophoresis (PAGE) patterns in the presence of the detergent sodium dodecyl sulfate (SDS) by reducing the number of bands compared to untreated samples [8]. The purpose of this study was to monitor changes in the albumin fraction of the protein of 4 sizes of peas in the raw, blanched and canned products, and the can brine solutions, using SDS-PAGE.     

On the response under different thermal treatments of the thermostable endopolygalacturonase produced byRhizopus nigricans

The influence of temperature and thermal treatments on the endopolygalacturonase activity produced byRhizopus nigricans was studied. The optimum temperature was at 50 °C. The enzymatic preparation also showed the highest endo pattern at this temperature. This endopolygalacturonase showed high thermostability between 90–100 °C and a bimodal behaviour in relation to the thermal treatments, because the enzyme was strongly inactivated at 70 °C. When the enzyme was treated at 90 and 70 °C consecutively, the inactivation at 70 °C was smaller.

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Einfluß der verschiedenen thermischen Behandlungen der thermostabilen Endopolygalacturonase vonRhizopus nigricans

Zusammenfassung Es wurde der Einfluß der Temperatur und der thermischen Behandlungen auf die Aktivität der Endopolygalacturonase vonRhizopus nigricans studiert. Hierbei wurde eine optimale Endtemperatur von 50 °C erreicht, wobei das Enzym seinen maximalen Charakter als Endo-Enzym belegt. Diese Endopolygalacturonase zeigt die größte Thermostabilität zwischen 90 °–100 °C und ein bimodales Verhalten, wenn man bedenkt, daß das Enzym bei 70 °C stark inaktiv ist. Wenn das Enzym zweimal hintereinander bei 90 °C und 70 °C behandelt worden ist, hat dies die Konsequenz, daß die Inaktivität bei 70 °C weniger ist.

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In memory of Dr. José María Núñez (1959–1990)