Determination of temperature processing demage in soybean products

In this study, it was aimed to determine the nutritional contents of raw soybeans, full-fat soybeans (FFS) produced with different heat treatments, and soybean meals (SBM) with different protein contents by both chemical and NIR spectrophotometric methods. In addition, it was aimed to measure the heat treatment parameter values by NIR spectrophotometric method. This study was conducted with samples collected from large capacity soybean feed producers. Raw soybean and FFS samples were collected from full fat soybean producing enterprises at different process temperatures. Twent-five samples were taken for each treatment group and a total of seventy-five samples were analyzed. Groups the from research included control group with the raw-soybean, full-fat soybeans processed at the usual cooking temprature of 119-134 oC (FFS-NS), and full-fat soybeans processed at a high cooking temprature of 135-140 oC (FFS-FS). At the same time, a total of 50 soybean meal (SBM) samples were collected from different commercial feed undertakings. According to the results of analysis, the samples were seperated into two groups based on their crude protein contents 44-46% HP (SFK-A) and 47-48,5% HP (SFK-B). Chemical analyzes of all samples (dry matter, crude ash, crude protein, ether excrate) were conducted. Essenstial nutrient analyses, lysine and methionine amino acid analyses, thermal processing analyses (Protein dispersibility index, protein solubility in KOH, trypsin inhibitor activity, reactive lysine) were conducted on the same samples using a Near Infrared Reflection Spectrophotometer (NIRS), and reactive Lysine values were determined. According to the chemical and spectrophotometric analyses of FFS, differences in dry matter (DM, ash, crude protein (CP), ether excrate (EE) and nötral detergent fiber (NDF) values between raw soybeans and FFS roasted at two different temperatures were observed (p<0,05). At the same time, according to the spectrophotometric analysis results, the lysine and methionine values of the FFS groups processed at different temperatures were found to be higher than those of the raw soybean group (p<0,05). Among the thermal processing parameters, the Protein Dispersibility Index (PDİ) value was lower in the full-fat soybean groups, while the KOH protein solubility (KOH-PS) and Trypsin Inhibitor Activity (TIA-A) values exhibited a linear decrease with increasing temperature in the full-fat soybean groups (p<0,05). According to the chemical and NIR Spectrophotometric analyses of the SBM groups, the differences in CP, crude fiber (CF), acid detergent fiber (ADF), NDF and fosfor (P) values between two meal groups was found to be significant (p<0,05). Addtionally, the NIR spectrophotometric levels of methionine and lysine amino acids in the SFK-B group were higher compared to the SFK-A group (p<0,05). Morover, the protein dispersibility index (PDI) value of the SFK-A group was lower than that of the SFK-B group, while KOH protein solubility (KOH-PS) values showed similar results across both soybean meal groups. The trypsin inhibitör activity (TIA-A) and reactive lysine (R-lysine) values of the SFK-A group were lower than those of the SFK-B group (p<0,05). According to the results from both anaylsis methods, there are significant differences between production methods and contents of TYS and SFK in market. Variations in thermal processing parameters were observed, depending on the applied temperature or protein content, for both FFS samples and SBM samples. In vivo studies, particularly feeding trials with broiler chickens of different ages, are necessary for a more comprehensive evaluation of the quality of FFS and SBM and their effects on these heat treatment parameters. Key Words: Amino acid, Anti-nutritional factors, Heat treatment, Koh-ps, Pdı, Reactive lysine, Soybean, Trypsin inhibitory activity.