Determination of selected protoporphyrins in parma ham with use of 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin as a surrogate standard in the recovery study

A high-performance liquid chromatographic method for the determination of hemin, protoporphyrin IX (PPIX), and zinc(II)protoporphyrin IX (Zn(II)PPIX) in Parma ham was developed. The detection was done by means of a universal DAD-detector, whereby quantification of the three naturally occurring protoporphyrins was carried out at lambda = 414 nm, i.e., very close to the respective maxima of their Soret bands. The extraction thereof from the meat matrix was done by a mixture of acetone and chloroacetic acid (100 mL + 0.2 g). Usage of 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin (THPP) as a surrogate standard and its detection fixed at lambda = 444 nm, allowed to obtain accurate (ca. 96%) recovery results. Established concentrations of hemin, Zn(II)PPIX, and PPIX in the Parma ham samples were 15.97, 19.96 and 1.52 µg g(-1), respectively.

The occurrence of N-nitrosamines, residual nitrite and biogenic amines in commercial dry fermented sausages and evaluation of their occasional relation

Regarding food borne intoxications, the accumulation of biogenic amines must be avoided in all kinds of food products. Moreover, biogenic amines can function as precursors for the formation of carcinogenic N-nitrosamines when nitrite is present. To estimate the food safety of the dry fermented sausages available on the Belgian market, a screening of the residual sodium nitrite and nitrate contents, biogenic amines and volatile N-nitrosamine concentrations was performed on 101 samples. The median concentrations of residual NaNO2 and NaNO3 were each individually lower than 20mg/kg. In general, the biogenic amine accumulation remained low at the end of shelf life. Only in one product the amounts of cadaverine and putrescine reached intoxicating levels. Concerning the occurrence of N-nitrosamines, only N-nitrosopiperidine and N-nitrosomorpholine were detected in a high number of samples (resp. 22% and 28%). No correlation between the presence of N-nitrosamines and the biogenic amines content was observed. Although the N-nitrosamines could not been linked to specific product categories, the occurrence of N-nitrosopiperidine could probably be attributed to the use of pepper.

Influence of organic matter generated by Chlorella vulgaris on five different modes of flocculation

Microalgae excrete relatively large amounts of algal organic matter (AOM) that may interfere with flocculation. The influence of AOM on flocculation of Chlorella vulgaris was studied using five different flocculation methods: aluminum sulfate, chitosan, cationic starch, pH-induced flocculation and electro-coagulation-flocculation (ECF). The presence of AOM was found to inhibit flocculation for all flocculation methods resulting in an increase of dosage demand. For pH-induced flocculation, the dosage required to achieve 85% flocculation increased only 2-fold when AOM was present, while for chitosan, this dosage increased 9-fold. For alum, ECF and cationic starch flocculation, the dosage increased 5-6-fold. Interference by AOM is an important parameter to consider in the assessment of flocculation-based harvesting of microalgae.

Flocculation of Chlorella vulgaris induced by high pH: role of magnesium and calcium and practical implications

Microalgae hold great potential as a feedstock for biofuels or bulk protein or treatment of wastewater or flue gas. Realising these applications will require the development of a cost-efficient harvesting technology. Here, we explore the potential of flocculation induced by high pH for harvesting Chlorella vulgaris. Our results demonstrate that flocculation can be induced by increasing medium pH to 11. Although both calcium and magnesium precipitated when pH was increased, only magnesium (≥0.15 mM) proved to be essential to induce flocculation. The costs of four different bases (sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and sodium carbonate) were calculated and evaluated and the use of lime appeared to be the most cost-efficient. Flocculation induced by high pH is therefore a potentially useful method to preconcentrate freshwater microalgal biomass during harvesting.