Biochemical composition and quality of herring preserves with addition of bio-protective cultures

J. Bazarnova, N. Korableva, O. Ozerova and E. Moskvicheva*

Peter the Great St.Petersburg Polytechnic University Graduate School of Biotechnology and Food Science, Polytechnicheskaya, 29, RU195251 St. Petersburg, Russia
Correspondence: EVtechnolog@yandex.ru

Abstract:

Herrings rich in vitamins B12, A, D, minerals, including calcium, potassium, magnesium, iodine, possess high levels of lysine, tyrosine, phenylalanine and tryptophan, as well as omega-3 unsaturated fatty acids, namely eicosapentanoic, docosahexoenoic and docosapentoenoic. To suppress the microbiological spoilage of fish preserves, it is promising to use bio-protective cultures that have minimal impact on the production process and product properties. Bacterial strains are able to exert a static effect on the microflora, which causes biodeterioration of food products. Microorganisms as part of bio-protective cultures are included in the fermentation process, so they can be attributed to ordinary food ingredients, so there is no need to put separate information on the packaging. The chemical composition of the frozen Atlantic and Pacific herring fillet, the amino acid composition of proteins, and the fatty acid composition of lipids were studied. The difference between Atlantic and Pacific herrings was detected, which consists in a significantly higher content of docosahexaenoic acid. The difference in the fractional composition of triacylglycerols for the Atlantic and Pacific herring was established. The microflora of SafePro B-2 biological product (Chr. Hansen GmbH), containing multiple strains of Lactobacillus sakei, and the viability of the culture in preserves fillings were studied. The experimental development of canned food with SafePro B-2 additives was carried out. Microbiological, organoleptic and biochemical indicators of the preserves quality during cold storage were studied. The influence of introduced culture on the dynamics of preserves curing period and their shelf life was established.

Key words:

bio-protective cultures, buffering, curing period, fatty acid composition, fillings, frozen fillet of Atlantic and Pacific herrings, preserves, triglycerides

Exhaust particle number of a non-road diesel engine fuelled by methyl esters with different fatty acid compositions

T. Ovaska*, S. Niemi, K. Sirviö and O. Nilsson

University of Vaasa, School of Technology and Innovations, P.O. Box 700, FI-65101 Vaasa, Finland
*Correspondence: teemu.ovaska@univaasa.fi

Abstract:

The main aim of this study was to find out how methyl esters with different fatty acid compositions affect the exhaust particle numbers. Along with fossil diesel fuel oil (DFO) and renewable diesel (HVO), a high-speed non-road diesel engine was fuelled by rapeseed (RME) and soybean (SME) methyl esters. Particle numbers within the size range of 5.6–560 nm were measured by means of an engine exhaust particle sizer (EEPS). The exhaust smoke, gaseous emissions and the basic engine performance were also determined. During the measurements, the 4-cylinder, turbocharged, intercooled engine was run according to the non-road steady cycle. Methyl esters reduced particles within the size range of 70 to 200 nm. For RME and SME, both positive and significant correlations were found between the sum of the particle numbers detected above the size category of 23 nm and methyl palmitate (C16:0), methyl stearate (C18:0) and methyl linoleate (C18:2) contents at 10% load at rated speed. In terms of nitrogen oxide (NOx) and hydrocarbon (HC) emissions, HVO was beneficial while carbon monoxide (CO) emission was the lowest with DFO. The level in smoke emission was negligible.

Key words: