Effects of Surface Treatment with Thymol on the Lipid Oxidation Processes, Fatty Acid Profile and Color of Sliced Salami during Refrigerated Storage

The oxidation of unsaturated fatty acids and the adverse transformation of pigments from meat and spices are the primary causes of chemical degradation in processed meat products. Thymol is found in a variety of plant extracts that have been proven to effectively inhibit or slow down oxidative processes. The objective of our study was to determine whether thymol treatment of the surface of sliced paprika salami could be applied to inhibit lipid oxidation and color change during refrigerated storage. During eight weeks of storage, the malondialdehyde (MDA) levels and the ratios of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and n6/n3 in thymol-treated salami remained unchanged (p ≥ 0.05), whereas in the controls, the MDA levels increased by approximately twelvefold and the ratio of SFAs in the lipid fraction increased (p < 0.001), while the ratio of PUFAs decreased (p < 0.001). The application of thymol prevented decrease in yellowness (b*) of the slices and reduced decreases in redness (a*) and brightness (chroma).

Carcass characteristics and meat quality of Hungarian Simmental young bulls fed different forage to concentrate ratios with or without linseed supplementation

Abstract. In total, 30 Hungarian Simmental bulls were reared to 300.07 ± 43.78 kg initial live weight and 274.57 ± 19.73 d of age. Animals were distributed into three feeding groups with different maize silage to concentrate ratios (670 : 330 = F/ HC; 750 : 250 = F/ LC 1; 800 : 200 = F/ LC 2) based on dry matter. The low concentrate groups (F/ LC 1 and F/ LC 2) received linseed supplemented concentrate during the fattening period. Feeding high concentrate (F/ HC) caused the significantly highest daily gain. The slaughter weights, dressing (%), lean (%) and fat (%) did not show any significant differences between feeding groups. Carcass conformation of all groups was assessed mainly as U. Bulls of group F/ LC 2 had the lowest amount of kidney fat. Bone proportion of the carcasses was affected by the diet (F/ HC: 18.65 %; F/ LC 1: 18.41 %; F/ LC 2: 17.91 %). The tendon proportions were lower in groups F/ LC 1 and F/ LC 2 but not significantly (F/ HC: 1.15 %; F/ LC 1: 1.1 %; F/ LC 2: 1.08 %). The intramuscular fat content varied between the three muscles investigated. Psoas major muscle contained the highest fat concentration in all three feeding groups. The mineral content of muscles (iron [Fe], copper [Cu], zinc [Zn]) was only affected by muscle type, but not by diet. In linseed supplemented groups (F/ LC 1 and F/ LC 2) the palmitic acid and palmitoleic acid proportion was decreased (P<0.05) in all muscles and the linolenic, eicosapentaenoic and the sum of n-3 fatty acid (P<0.05) was increased compared to the F/ HC group. The beef from groups F/ LC 1 and F/ LC 2 bulls showed a lower n-6 to n-3 fatty acids ratio (P<0.05). The relative and absolute concentration of CLAcis-9,trans-11 was unaffected by diet but muscle type caused changes.

The influence of extrusion on loss and racemization of amino acids

The influence of the operation conditions (temperature and residence time) of a thermic treatment on the total amount (free and protein-bound) of amino acid enantiomers of dry fullfat soya was investigated. Total amino acid content was determined using conventional ion-exchange amino acid analysis of total hydrolysates and chiral amino acid analysis was performed by HPLC after precolumn derivatization with o-phthaldialdehyde and 1-thio-beta-D-glucose tetraacetate. Contrary to corn that was investigated previously, notable racemization was detected even at lower temperatures. At 140 degrees C the ratio of the D-enantiomer was 0.87% for glutamic acid, 2.81% for serine, and 1.92% for phenylalanine; at 220 degrees C the ratios of the D-enantiomer of the above amino acids were 1.43, 4.61, and 4.68%, respectively. The concentration of several L-amino acids decreased. At 220 degrees C there was 10% less L-glutamic acid, 17% less L-serine, 5% less L-phenylalanine, 6.6% less L-aspartic, acid and 21% less L-lysine than in the control; their loss can be assigned to different degrees of L - D conversion. While nearly complete transformation of L-phenylalanine can be attributed to racemization, the main cause of the loss of L-lysine is not racemization. The treatments in the same order of magnitude resulted in the formation of more D-amino acids and greater extent of racemization of amino acids in fullfat soya than that of maize.

The influence of manufacture on the free D-amino acid content of Cheddar cheese

The changes in the concentration and those of composition of alanine, aspartic acid and glutamic acid enantiomers were investigated during manufacture of Cheddar cheese. The amount of D-alanine increased continuously during ripening following the liberation of L-alanine originated from the proteolysis of milk proteins. There was slightly more D-aspartic and D-glutamic acid in the dry matter of curd after pressing than before pressurization. The D-amino acid content and the ratio of the D-enantiomers related to the total amount of free amino acids differed significantly among cheeses produced with different single-strain starters. The D-amino acid composition changed during manufacture, but the influence of the strain selection was not significant on the D-amino acid pattern.