Efeitos das condições de armazenagem sobre a qualidade da soja (Glycine max (L.) Merrill) e do óleo bruto / Effects of storage conditions on the quality of soybean grains (Glycine max (L.) Merrill) and crude oil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Brazil s 2005/06-grain production is forecast at approximately 123 million tons. Of this total, Brazil should produce 57 million tons of soybean grains, i.e., 46% of the national production. Brazilian agricultural production, however, needs to meet the international demands in order to gain foreign markets, maintaining good quality of grains is therefore essential. Soybean grains have a lipid content of approximately 20% and are susceptible to quality deterioration when inadequately stored, which can lead to serious problems such as damages to the quality of crude, refined, bleached and deodorized oil. The objective of this work was to evaluate the main qualitative changes in soybean grains during storage and the influence of these changes on the quality of the extracted crude oil. Grains, with approximately 18% moisture content at harvest, dried in a fixed bed dryer with natural air to moisture contents of 11.2, 12.8 and 14.8% w.b. were used in the experiment. After drying, the grains were stored in plastic containers of approximately 3.0 L and taken to BOD incubators, at 20, 30 and 40 C. To guarantee the same grain moisture content during storage at different temperatures, the Equilibrium Relative Humidity (RHe), previously calculated for each temperature combination and moisture content inside each BOD. Acquisition and storing of relative humidity data was performed by a 1-wireTM system. Qualitative analyses of grains and crude oil were carried out every 45 days, within a period of 180 days of storage. The qualitative parameters of soybean grains stored with different moisture contents and combinations of different temperature and relative humidity were moisture content, classification, apparent specific mass, electrical conductivity, germination, lipid content and color. The quality of extracted crude oil was evaluated through the analyses of iodice value, free fatty acid, peroxide value and photometric color index. The experiment was arranged in completely randomized split-plots, with three repetitions. The treatments, temperature combinations (20, 30 and 40 C) and moisture content (11.2, 12.8 and 14.8% w.b.) were allocated in the main plot, whereas the subplot consisted of the storage periods (0, 45, 90, 135, 180 days), with the treatments arranged into a 3×3×5 factorial design. Data analyses and interpretation of results led to the following conclusions: for certification purposes, soybean storage is not recommended in the following combinations of moisture content and temperature: 11.2% w.b. at 40 C; 12.8% w.b. at 30 and 40 C; and 14.8% w.b. at 20, 30 and 40 C; for soybean commercialization within the limits of base reference, it is possible to store grains with moisture content up to 14.8% w.b. at 20 and 30 C for 180 days; at 40 C, only grains with moisture content of 11.2% w.b. can be stored for 180 days; grains with moisture content of 12.8 and 14.8% w.b. at 40 C can be stored for 90 and 45 days, respectively. The results of qualitative parameters of oil from grains stored in the different conditions led to the conclusion that storage of grains with moisture content up to 14.8% w.b. at 20 C does not affect the quality of crude oil; crude oil extracted from grains stored with moisture content up to 12.8% w.b. at 30 C keeps satisfactory quality up to 180 days; it is not possible to obtain crude oil that complies with the quality standards demanded for commercialization from grains stored with moisture content above 11% w.b. at 40 C; qualitative traits of soybean grains affect the quality of the extracted crude oil. Proposed preventive measures of post-harvest handling to reduce risks of quality loss in soybean grains and byproducts are: store soybean grains with moisture content up to 15% w.b. at 20 C without risk of deterioration up to 180 days; in regions with temperatures around 30 C, store soybean with moisture content up to 13% w.b.; do not store soybean with moisture content above 11% w.b. in regions where the grain mass temperature can reach 40 C with the risk of accelerating deterioration of grains and byproducts.

ASSUNTO(S)

Óleo de soja armazenamento storage engenharia de processamento de produtos agricolas quality soybean oil soja soybean qualidade

ACESSO AO ARTIGO

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