Resumen

PIZZANI, Pablo et al. De canavalia ensiformis (l.) Effects of toasting on true metabolizable energy value and content of antinutritional factors of canavalia ensiformis (l.) Seed meals. Rev. Cient. (Maracaibo) [online]. 2006, vol.16, n.5, pp.523-530. ISSN 0798-2259.

The effects of toasting on the True Metabolizable Energy, corrected to zero nitrogen retention (TMEn) and content of antinutritive factors (ANF) present in Jack Beans (JB, Canavalia ensiformis) seeds were investigated in a balance trial. Reactive lysine, protein solubility, and color were also determined in experimental meals. Raw JB meal was toasted at the following combinations of temperature and time: 180; 200; 220 and 230°C/3min; 230 and 240°C/2min; and 230 and 240°C/1min. Five caecectomised cockerels were randomly assigned to each JB meal (raw or toasted). Each bird was intubated 40g of a given meal and excreta were quantitatively collected during 72h. Concanavalin A binding to duodenal mucosa was assessed by immunohistochemistry. No hemaglutinating activity was detected in toasted JB but Con A binding to duodenal mucosa ranged from moderate to weak. Toasting JB meal at 220; 230°C/3min; and 240°C/2min reduced the original canavanine content of JB in more than 90%. TMEn value of raw JB was not improved by toasting. No significant differences were found between TMEn of raw JB and those of JB toasted at 200; 220; 230°C/3min; 240°C/1min or 240°C/2min, whereas toasting JB meal at 180°C/3min; 230°C/1min or 230°C/2min significantly (P < 0.05) reduced TMEn. Reactive lysine and protein solubility were reduced (P < 0.05) as both temperature and toasting time increased. Meal color was also affected (P < 0.05) by toasting. In summary, under the conditions tested, toasting can effectively reduce ANF content in raw JB. However, this positive response did not improve the TMEn value of raw JB

Palabras clave : Jack beans; Canavalia ensiformis; TMEn; antinutritive factors; canavanine; concanavalin A; roosters.