Dl methionine sulfone

The water-holding capacity (WHC) of the pork was measured by centrifuge. Three LM samples were ground and placed in a filter tube, then heated in a water bath at 80°C for 20 min, and centrifuged for 10 min at 2,000 rpm at 10°C (Eppendorf centrifuge 5810R, Germany). To calculate the cooking loss, the LM samples were packed in a polyethylene bag, heated in a water bath until the core temperature reached 72°C, and weighed before and after heating. After heating, the samples were cored (0.5×1.0×1.5 cm) parallel to the muscle fiber and the cores were used to measure the shear force using a salter (Warner Barzler Shear, Norwood, MA, USA). The amino acid content of the loin meat was determined by ion-exchange chromatography (Amino Acid Analyzer L-8900, Hitachi, Tokyo, Japan) with post-column derivatization with ninhydrin. Performic acid was used in oxidizing the amino acids and was neutralized with sodium citrate dihydrate and then hydrolyzed with 6 N HCl for 22 hours at 110°C to be liberated from the protein. Amino acids were quantified with the internal standard method (amino acid mixture standard solution Type H, Wako Chemical, Osaka, Japan; L-cysteic acid, Tokyo Chemical Industry, Tokyo, Japan; DL-methionine sulfone, Sigma, St. Louis, MO, USA) by measuring the absorption of the reaction products with ninhydrin at 570 nm.

All reagents were of analytical grade. Methanol (MeOH), acetonitrile (ACN), and acetic acid (HAc) were acquired from Scharlau Chemie (Barcelona, Spain). Triethylamine (TEA) and 9-fluorenylmethoxycarbonyl (FMOC) chloride were obtained from Fluka (Buchs, Switzerland). Ammonium hydroxide (NH₃·H₂O), boric acid (H₃BO₃) and pentane were from Sigma (St. Louis, Missouri, USA), and ammonium acetate was from Merck (Darmstadt, Germany). 10,11-dihydroquinidine, 2,2’-azobisisobutyronitrile (AIBN), 3-(trimethoxysilyl)-propylmethacrylate (γ-MAPS), vinyltrimethoxysilane (VTMS), cetyltrimethylammonium bromide (CTAB), tetramethoxysilane (TMOS) and ethylene glycol (EG) were acquired from Aladdin Chemicals (Shanghai, China). dl-arginine, dl-histidine, dl-lysine, dl-serine, dl-threonine, dl-asparagine, dl-glutamine, dl-cysteine, dl-proline, dl-alanine, dl-valine, dl-leucine, dl-methionine, dl-phenylalanine, dl-tyrosine, d-tryptophan, l-tryptophan, dl-ornithine, dl-citrulline standards were from Fluka (Buchs, Switzerland), while dl-isoleucine, dl-carnitine, dl-aspartic acid, dl-glutamic acid, dl-norvaline, l-norvaline, dl-norleucine, dl-DOPA, dl-pyroglutamic acid and dl-methionine sulfone were obtained from Sigma (St. Louis, Missouri, USA). FMOC-amino acids were synthesized as reported previously [29 (link),30 (link)]. The dietary supplements were obtained in capsule form from online sources.