ABSTRACT
In this experimental study, biodiesel was synthesized from the salmon oil using the Lipozyme®RM IM (Bagsværd, Denmark) as a biocatalyst. Isoamyl alcohol was used as an acyl acceptor in the transesterification process. The aim of this study is to select the best process conditions, aiming to obtain the highest transesterification degree that meets the requirements of the EN 14214 standard. Response surface methodology (RSM) was used for statistical analysis and optimization of process parameters. A four-factor experimental design was modelled by central compositional design (CCD) to investigate the effects of biocatalyst concentration, isoamyl alcohol-to-oil molar ratio, temperature, and duration on transesterification degree. It was determined that the optimal parameters for biodiesel synthesis were the following: an enzyme concentration of 11% (wt. of oil mass); a process temperature of 45 °C; a process duration of 4 h; and an alcohol-to-oil molar ratio of 6:1. The transesterification degree of biodiesel reached 87.23%. The stepwise addition of isoamyl alcohol during the transesterification process further increased the degree of transesterification to 96.5%.
ABSTRACT
This study aims to evaluate the ability of raspberry and blackberry pomace to inhibit lipid oxidation and prolong the refrigerated storage of beef patties. Berry pomace was incorporated into beef patties at the concentration of 1, 3, and 5%. Packed patties were stored for 9 days at 4 °C temperature and the quality of the meat was evaluated on the 0, 3rd, 6th, and 9th day. The natural mass loss during storage, the pH as well as the lipid oxidation were evaluated by thiobarbituric acid-reactive substance (TBARS) method. GC was used to determine the amount of fatty acids and e-nose, based on ultrafast gas chromatography, was used for the determination of volatile organic compounds in beef patties before and after the storage. The highest mass loss during refrigerated storage was observed in the control beef patties, while the berry pomace absorbed water and reduced the loss. The pomace additive influenced the decrease in the patties pH during the storage. Berry pomace can be very effective in relation to lipid oxidation, and as little as 1% of berry pomace influenced the decrease in the TBAR's values in the patties stored for nine days by 3.06 and 2.42 times, depending on the pomace compared to the control patties. The use of berry pomace in meat products can reduce lipid oxidation, increase their fiber content and act as a thickener, as well as contribute to the usage of agri-food by-products.
