Porcentagens de saponinas e taninos em vinte e oito cultivares de alfafa (Medicago sativa L.) em duas épocas de corte - Botucatu - SP
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Data
2001-10-01
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Sociedade Brasileira de Zootecnia
Resumo
O objetivo do estudo foi determinar os conteúdos de saponinas, taninos e a solubilidade da proteína (SP) de 28 cultivares de alfafa: Crioula, Monarca, BR 4, Alto Great, MH 4, SW 9210 A, 5929, BR 1, EL Grande, 5715, MH 15, Valley Plus, BR 2, Rio, SW 8210, Maricopa, ICI 990, 5888, P 30, Alfa-200, WL 516, SW 8112 A, BR 3, Florida 77, Araucana, Falcon, Semit 921 e Sutter. O material analisado foi obtido do 10º e 14º corte, respectivamente; em 08/12/97 e 16/04/98, de um experimento desenvolvido na Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu. Amostras de cada cultivar foram colhidas, pesadas e secas em estufa a 52ºC. As saponinas foram extraídas com solvente hidrofílico e lipofílico e o conteúdo foi calculado pela equação y=0,8121x-1,4759, R² = 1,00. A extração dos taninos totais e condensados foi efetuada por meio de ultra-som (12 min), sendo os taninos totais determinados pela equação: y=44,978 + 0,5644 com R²=0,9977 e os condensados, multiplicando-se a absorbância por 78,26 dividido pelo teor de matéria seca. A SP foi determinada pelo método de KOH, de acordo com a seguinte fórmula: SP (%) = proteína solúvel x 100/proteína bruta da amostra. Os teores de saponinas, taninos totais e condensados e a solubilidade da proteína não diferiram (P>0,05) entre as cultivares. Houve efeito (P<0,05) da época de corte apenas sobre o teor de taninos totais. Os teores médios de saponinas de 1,00% aliados à baixa solubilidade média da proteína bruta (34,11%) não se constituem em fatores limitantes para uso dos cultivares de alfafa estudadas.
The experiment was carried out to evaluate saponins and tannins contents, the proteins solubility (PS) of 28 alfalfa cultivates: Crioula, Monarca, BR 4, Alto Great, MH 4, SW 9210 A, 5929, BR 1, El Grande, 5715, MH 15, Valley Plus, BR 2, Rio, SW 8210, Maricopa, ICI 990, 5888, P 30, Alfa-200, WL 516, SW 8112 A, BR 3, Florida 77, Araucana, Falcon, Semit 921 and Sutter. The analyzed material came from the 10th and 14th harvests (which occurred on 12/08/97 and 04/16/98, respectively) from an experiment conducted at the College of veterinary medicine and Animal Science, UNESP, Botucatu. Samples from each cultivate were weighed and oven-dried at 52ºC. Saponins were extracted with a hydrophilic and lipophilic solvent, and their content was calculated by means of the following equation: y = 0.8121x - 1.4759 (R² = 1.00). Total and condensed tannins were ultrasound-extracted for 12 min. Total tannin content was calculated by means of the following equation: y = 44.978 + 0.5644 (R² = 0.9977); condensed tannin content was determined by multiplying the absorbency by 78.26 and dividing it by the dry matter content. PS was determined through the KOH method, using the following formula: PS (%) = (100) (soluble protein) / crude protein. No differences were detected (P>0.05) among cultivates in saponin content, total tannin and condensed content of PS. Harvest time effect was observed (P<0.05) in total tannin content only. The low average saponin content (1.0%) and protein solubility (34.11%) do not constitute a limiting factor for the use of the above alfalfa cultivars.
The experiment was carried out to evaluate saponins and tannins contents, the proteins solubility (PS) of 28 alfalfa cultivates: Crioula, Monarca, BR 4, Alto Great, MH 4, SW 9210 A, 5929, BR 1, El Grande, 5715, MH 15, Valley Plus, BR 2, Rio, SW 8210, Maricopa, ICI 990, 5888, P 30, Alfa-200, WL 516, SW 8112 A, BR 3, Florida 77, Araucana, Falcon, Semit 921 and Sutter. The analyzed material came from the 10th and 14th harvests (which occurred on 12/08/97 and 04/16/98, respectively) from an experiment conducted at the College of veterinary medicine and Animal Science, UNESP, Botucatu. Samples from each cultivate were weighed and oven-dried at 52ºC. Saponins were extracted with a hydrophilic and lipophilic solvent, and their content was calculated by means of the following equation: y = 0.8121x - 1.4759 (R² = 1.00). Total and condensed tannins were ultrasound-extracted for 12 min. Total tannin content was calculated by means of the following equation: y = 44.978 + 0.5644 (R² = 0.9977); condensed tannin content was determined by multiplying the absorbency by 78.26 and dividing it by the dry matter content. PS was determined through the KOH method, using the following formula: PS (%) = (100) (soluble protein) / crude protein. No differences were detected (P>0.05) among cultivates in saponin content, total tannin and condensed content of PS. Harvest time effect was observed (P<0.05) in total tannin content only. The low average saponin content (1.0%) and protein solubility (34.11%) do not constitute a limiting factor for the use of the above alfalfa cultivars.
Descrição
Palavras-chave
conteúdo, época do ano, taninos condensados, ultra-som, content, condensed tannins, harvest time, ultrasound
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 30, n. 5, p. 1432-1438, 2001.