ABSTRACT This study aimed to determine the efficacy of a finishing diet added with sugar beet pulp to reduce backfat skatole of entire male pigs, using the optimised high-performance liquid chromatographic (HPLC) method. The study comprised 72 males Pietrain (Large White × Landrace), divided into two groups of 36 animals each. Pigs in group A (treatment) were fed a supplemented formula (addition of 10 % beet pulp). while animals in group B (control) received a commercial feed, both for a period of 14 days before slaughter. The isocratic HPLC method achieved the chromatographic separation of indolic compounds in approximately 3 min. Skatole was significantly lower ( p = 0.002) in group A, showing that beet root supplementation reduced skatole levels in pig fat. In addition, the optimised HPLC method was reliable, less time-consuming, and showed a resolution suitable for small amounts of skatole. pigs highperformance high performance (HPLC 7 Large Landrace, Landrace , Landrace) each treatment (treatment addition 1 pulp. . pulp) control (control feed slaughter min 0.002 0002 0 002 fat reliable timeconsuming, timeconsuming time consuming, consuming time-consuming 0.00 000 00 0.0 0.

Dois métodos de purificação de plantaricin ST31, uma bacteriocina produzida por Lactobacillus plantarum ST31 foram usados neste estudo - o método de precipitação pelo sulfato de amônia usando cartucho Sep-pack C18 para a filtração e HPLC de fase reversa em coluna de C18 Nucleosil, e o método de purificação direta por troca catiônica SP Sepharose "Fast Flow column Amersham" (Pharmacia Biotech). A pureza dos produtos obtidos pelos dois protocolos foi examinada através da determinação dos pesos moleculares, composição e seqüência dos aminoácidos. A comparação destes resultados revelou que, em termos da pureza dos produtos, não havia diferenças entre os dois métodos de purificação podendo-se, portanto, utilizar qualquer um dos protocolos de purificação testados. No entanto, o rendimento da purificação pelo método da troca catiônica foi de 5.9% enquanto o do método HPLC foi de 0.8%.

Two methods of purification of the plantaricin ST31, a bacteriocin produced by Lactobacillus plantarum ST31 are used in this study - the method of ammonium sulfate precipitation, Sep-pack C18 cartridge and reverse-phase HPLC chromatography on C18 Nucleosil column, and the method of direct purification by cation exchange SP Sepharose Fast Flow column Amersham (Pharmacia Biotech). The purity of the products from the two experimental protocols are examined for their molecular weight, aminoacid composition and sequence. Comparison of results show that the plantaricins purified with the two methods are identical. Both methods may be used to purify plantaricin ST31. Comparison of the yield in the purification protocols is 0.8% in the HPLC experimental protocol and 5.9% in the cation-exchange chromatography method.