Chemical, In Vitro, and In Vivo Evaluation of Soybeans Heat-Treated by Various Processing Methods

Abstract

In trial 1, eight Holstein heifers weighing 410 kg were used in an 8 x 8 Latin square and fed TMR containing 79.3% alfalfa silage and 20% soybeans. The first four treatments were raw soybeans, soybeans roasted and held for 3 h at the roasting temperature, extruded soybeans, and soybeans roasted in a California Pellet Mill Jet-Sploder. The remaining four treatments were obtained by altering the residence time of soybeans in the Jet Sploder. The temperatures of soybeans exiting the roaster were 117, 126, 138, and 154 degrees C for the last four treatments. The soybeans held 3 h postroasting and the extruded soybeans resulted in the highest estimate of postruminal available lysine. Blood plasma concentrations of essential and branched-chain AA were highest in heifers fed soybeans held 3 h postroasting. In trial 2, 44 Holstein heifers weighing 150 to 250 kg were assigned randomly to one of four TMR. Diets consisted of 91.8% alfalfa silage and 7.5% of one of four soybean treatments. Treatments were raw soybeans, soybeans roasted in a drum roaster with an exit temperature of 146 degrees C, and those roasted with exit temperatures of 141 or 146 degrees C and held for .5 h. Estimated postruminal available lysine was higher for soybeans roasted and held versus roasted or raw soybeans. However, BW gain for heifers was similar across diets, averaging .90 kg/d for 12 wk. Concentrations of AA in plasma were not affected by diet. Overall, results support the recommendation of holding soybeans for at least .5 h following roasting.

In situ evaluation of the protein value of soybean meal and processed full fat soybeans for ruminants

“…In the same manner, the low ED of CP observed for FFS5, processed by toasting, was in the lower limit of the range observed for the extruded FFS samples. This was in line with the observation of Faldet et al [7] who found that soybean extrusion leads to a lower content of undegraded CP than toasting. On the other hand, the variation recorded within the solvent extracted SBM samples, as well as within the extruded FFS samples, was substantial, which shows that the use of a constant value for the ED of Protein value for ruminants of soybean products 461 a,b,c Means within columns for each item that do not share a common superscript differ (P < 0.05); SE: mean standard error.…”

Effect of heat processing on ruminal degradability and intestinal disappearance of nitrogen and amino acids in Iranian whole soybean

“…An increase in temperature from 117 to 154°C caused total Lys to decrease from 2.3 to 1.7% of DM (Faldet et al, 1992b). Lys is usually the most sensitive AA to heat processing and is often lost at levels 5-15 times greater than other AA (Dakowski et al, 1996), but our results show less negative effects on Lys.…”

“…The seeds traversed the cylinder tunnel (4-m length), so that the temperature of the beans exiting the roaster was 140 to 145°C. Then, some seeds were gradually cooled (about 1 h) and the rest were immediately placed and held for 45 min in 100-L isolated barrels covered with canvas before being allowed to cool (Faldet et al, 1992b). So a total of 6 feed samples (2 soybean cultivars which were raw, roasted or steep-roasted) were used in the study.…”

Roasted, steeped soybeans for growing steers fed alfalfa–grass silage

“…However, current commercial procedures to roast soybeans may not adequately protect protein from ruminal degradation (Ganesh and Grieve 1990;Faldet et al 1991a). Results from our laborarory (Mosimanyana and Mowat 1992) support earlier studies of Voss et al (1988) van Kuelen and Young (1977), and alkaline hydrogen peroxide lignin (APL), determined according to Cochran et al.…”