Effect of harvest at different times of day on the physical and chemical characteristics of vegetable-type soybean

Abstract

The objective of this study was to evaluate the effect of harvest at different times of day on the chemical and physical characteristics of vegetable-type soybean BRS 267 cultivar, harvested at the R6 stage (seed development) and to compare it with that on the grains harvested at the R8 stage (maturation). The pods of the BRS 267 cultivar were harvested at the R6 stage (at 8:00 AM, 12:00 AM, and 6:00 PM), the color parameters were evaluated, and the grains were analyzed for chemical composition, activity inhibitor trypsin, phytic acid content, starch, sugars, fatty acids, and isoflavones. No differences were observed among the different harvest times in terms of the chemical constituents of vegetable-type soybean BRS 267 cultivar harvested at the R6 stage. Isoflavones content did not change with different harvest times, and the aglycone forms (daidzein, glycitein, and genistein) were found in smaller quantities at the R6 stage compared to the R8 stage. The color of the pods of soybean BRS 267 cultivar, harvested at the R6 stage did not change with different harvest times. The grains harvested at the R6 stage had lower protein content, phytic acid, and sucrose and higher levels of lipids, carbohydrates, starch, glucose, fructose, stachyose, and linolenic acids than those collected at the R8 stage. The different times of harvest did not affect the quality of the vegetable-type soybean BRS 267 cultivar harvested at stage R6. Nevertheless, it is recommended to harvest in the morning, when the temperature is milder, like other vegetables, to facilitate and optimize its marketing and in natura consumption.

Isoflavone, anthocyanin, and fatty acid contents of vegetable-type soybean grains at different maturity stages

“…There were differences among the breeding lines and growth stages for isoflavone contents (Table 4). As observed by Santana et al (2012), total accumulation of β-glucosides and aglucones, for all lines, increased at 20 and 29%, respectively, from R6 to R8 (Table 4). Berger et al (2008) reported a continuous accumulation of total isoflavones up to maturity for soybean growing at a greenhouse and in the field.…”

Composição química dos grãos e da cera foliar de variedade Glycine max (L.) Merrill cv. MG/ BR-46 Conquista cultivada sob atmosfera enriquecida de gás carbônico e temperatura elevada

“…Em geral, as leguminosas oleaginosas tendem a perder níveis consideráveis de amido na maturidade (Baud et al, 2002;Hills, 2004), como foi observado nos resultados da Figura 14A. Os teores de amido reportados por Oliveira et al, (2010) (Dornbos & McDonald, 1986;Saravitz et al, 1987;Lowell & Kuo, 1989;Kumar et al, 2007;Santana et al, 2012), assim como em Brassica campestris (Leprince et al, 1990), trigo (Black et al, 1996) e Arabidopsis thaliana (Baud et al, 2002). A sacarose é peça central no metabolismo de carboidratos, sendo a principal forma do transporte de carbono pelo floema para as sementes em desenvolvimento.…”

“…A síntese de rafinose precisa de sacarose e galactinol, que aumentam concomitantemente com a atividade da enzima galactinol sintase, que usa o mio-inositol como substrato (Karner et al, 2004;Handley et al, 1983). Em soja, Santana et al (2012) quantificaram entre 10,3 µg/mg e 16,1 µg/mg de rafinose em R6 e R8, respectivamente; em cultivares dos E.U.A, foram reportados em média 6,9 µg/mg (Saldivar et al, 2011) e em cultivares brasileiros, 7,2 µg/mg (Oliveira et al, 2010 (Castillo et al, 1990).…”

“…Em relação às hexoses da soja quantificadas (frutose e glicose), Santana et al (2012) demonstraram que as concentrações mantiveram-se constantes ao longo do dia.…”

“…Os resultados sobre frutose mostrados na Figura 14C são coerentes com os dados da literatura (Konno, 1979;Saravitz et al, 1987;Hou et al, 2009;Oliveira et al, 2010;Saldivar et al, 2011;Santana et al, 2012) que mostram a tendência de redução de seu teor durante o desenvolvimento dos grãos. Similarmente, em Arabidopsis thaliana (Baud et al, 2002) os teores de frutose e glicose diminuíram durante o amadurecimento, embora no presente estudo se tenha observado que o teor de glicose aumentou.…”