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Área de BromatologiaEfeito do déficit hídrico em características químicas e bioquímicas da soja e na degradação da clorofila, com ênfase na formação de metabólitos incolores analysis of pigment contents, immediately after harvest and after 20 months of storage at room temperature. Acidity was measured additionally after 30 month of storage. Water activity and humidity were 0.6 -0.7 and 8.7 % -11.9 %, respectively, and did not change during storage time, but there was an increase in acidity, which alludes to lipase activity. The activity of lipoxygenase 1 was significantly prejudiced. Immediately after harvest, green pigments corresponded mainly to pheophytin a, followed by pheophytin b, small quantities of chlorophyll b and chlorophyll a and traces of other chlorophyll derivatives. After 20 months of storage almost all green pigments had VIII disappeared. Drought stress probably enhanced membrane permeability, which led to a lower pH and promoted transformation of chlorophylls to pheophytins.In the second part of the study, the advanced stage of natural chlorophyll degradation was investigated, in which the green colour of the seeds disappears. This stage corresponds to the formation of non-coloured chlorophyll catabolites (NCC), but there are controversies if those are the final products. Thus, the formation and degradation of NCC during soybean (Glycine max L. Merrill) maturation and two post-harvest drying temperatures was investigated. Soybean was harvested at six maturation sta ges and the formation of NCC was analyzed by HPLC after drying at 40°C and 60°C. All samples contained fractions with an absorption maximum at 320 nm, which are considered typical for NCC. The amounts of NCC increased until 114 days after plantation, and were significantly lower in advanced maturation stages. In samples dried at 40°C and 60°C, NCC amounts were lower, due to inferior initial chlorophyll levels. These results indicate that the NCC in soybeans might not be the final products of chlorophyll degradation. Their reduction in advanced maturation stages may be due to further metabolization.

The natural chlorophyll degradation results in noncolored chlorophyll catabolites (NCCs), but there are controversies if these are the final products. The formation and degradation of NCCs during soybean seed ( Glycine max L. Merrill) maturation and two drying temperatures were investigated. Soybean was harvested at six maturation stages. The effect of postharvest drying at 40 and 60 degrees C on the NCC formation was analyzed by high-performance liquid chromatography (HPLC), and results were expressed as areas under the curve. All samples contained fractions with an absorption maximum at 320 nm, typical for NCC. The amounts of NCC increased until 114 days after planting and were significantly lower in advanced maturation stages. These results indicate that the NCC in soybeans might not be the final products of chlorophyll degradation. Their reduction in advanced maturation stages may be due to further metabolization. Heating soybeans at 40 and 60 degrees C promoted unnatural chlorophyll degradation and impaired the formation of NCC.

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