Postharvest changes in physicochemical characteristics and free amino acids content of immature vegetable soya bean (Glycine max L.) grains

The aim of this study was to investigate the changes in physicochemical characteristics and free amino acid profile occurring in immature vegetable soya bbean during postharvest storage under three temperatures [5, 10 and 20 (control), ±1 °C] for 7 days. The results showed that a lower temperature provided an effective control in reducing weight loss, maintained firmness, delayed changes in the pod colour and soluble sugars concentration. Twenty‐two free amino acids in immature soya beans also identified by the ¹H NMR spectroscopy were strongly affected by postharvest temperature, and there were time‐specific differences in the concentration. Those significant differences in free amino acids concentration among storage conditions were closely associated with aspartate and glutamate degradation. Additionally, after 7‐day storage at 5 and 10 °C, the soya bean grains accumulated the highest amount of some essential and flavour amino acids, which revealed storage conditions selected should be dictated by the goal.     

Isolation and characterization of 11-S-globulins from sunflower seeds (Helianthus annuus L.)]

The isolation of II-S globulin, which is homogenous on sedimentation and gel chromatography (s020, w = II,8 S), from sunflower seeds is achieved by cryoprecipitation from solutions of high ion strength (I approximately 0.5 to 1.8) with simultaneous reduction of the salt concentration (I approximately 0.3) and repeated gel chromatography on Sephadex G-200. By this technique, the 7-S component which occurs in small quantity is isolated too. In solutions of low ion strength (I less than 0,3), the II-S globulin dissociates to give a 7-S component. At high or low pH values (greater than 9.0 and less than 3.0, respectively), the latter dissociates to give a 3-S component, and in the presence of urea it further dissociates to give subunits. In the presence of sodium of sodium chloride, the dissociation of the 3-S component may be inhibited. The various steps of dissociation can be studied by means of ultracentrifugal sedimentation, gel chromatography and gel electrophoresis.     

Isolation and characterization of main albumin fractions of seeds from sunflower (Helianthus annuus L.) and rape (Brassica napus L.)]

The main fractions of the albumins from sunflower and rapeseeds (isolated by means of precipitation with ammonium sulphate or tannin + caffeine and subsequent gel chromatography) are low-molecular, very basic proteins. Their molecular weights range from 10 000 to 16 000, and their isoelectric points (determined by isoelectric focusing and free electrophoresis) are situated at pH greater than 10.0. From the circular dichroism in the wavelength range from 200 to 240 nm it is deduced that the main fraction of the rape albumin is a well-structured protein with 40-46% alpha-helix in aqueous and salt-containing solutions. Denaturation by heating is achieved only at temperatures about 100 degrees C and pH values greater than 9. 20% alpha-helix are left after the action of 8 M urea. This conformational stability is explained by the presence of disulphide linkages in the molecule.     

Effect of exogenous spermine on quality and sucrose metabolism of vegetable soya bean (Glycine max L.) during cold storage

Vegetable soya bean deteriorates quickly after harvest at ambient temperature due to loss of green colour and consequent yellowing of grains. To seek an effective method to control the postharvest quality, the effect of exogenous spermine on visual quality, sugar loss and sucrose‐metabolising enzyme activities of vegetable soya bean (Glycine max L.) during cold storage was investigated. The results showed that exogenous spermine (1.0 mmol L^?1) noticeably prolonged shelf life, inhibited the increase of weight loss and decay index and retained the colour. It also significantly minimised sucrose loss by regulating the activities of sucrose‐metabolising enzymes. Sucrose content negatively correlated with acid invertase (AI) activity at P < 0.05, while positively with sucrose phosphate synthase (SPS) activity at P < 0.01. There was no significant correlation with the activities of neutral invertase and sucrose synthase. These results indicated that the AI and SPS activities might play an important role in the control of sucrose metabolism resulting in reduction of sucrose loss.     

Trypsin inhibitor activity in the field bean (Vicia faba L.)

In vitro evidence is presented for the presence of a heat-labile inhibitor of trypsin in both cotyledon and testa of the field bean (Vicia faba L.). Inhibitor activity is destroyed by heating at 110°C for 40 min. The inhibitor has, in vitro, approximately one fifth of the strength of an extract of raw soyabeans.     

Isolation and catalytic actions of polyphenoloxidase from sunflower seeds (Helianthus annuus)

In the last few decades, biotechnological applications of phenoloxidase enzymes have become an area of significant interest. In this study, sunflower seeds, seedlings and defatted mill cake were investigated as possible plant source of polyphenoloxidase (PPO). Noticeable variation of chlorogenic acid concentration in each raw material has undoubtedly proven that only sunflower seedlings have significant amounts of active PPO. The activity of the enzymes was assessed by measuring the molar decrease of caffeic acid. Isolated protein powders from each raw material confirmed the presence of PPO only in the seedlings. Catalytic action of the PPO of seedlings was compared to that of the commercial laccase from Trametes versicolor. Sunflower PPO was selectively active on caffeic and chlorogenic acids, less active on ferulic acid and not active on mono-phenols and gallic acid. Conversely, laccase was highly active on all the assessed phenols. PPO activity was good in a large range of pH (4–8), whilst it was approximately halved in solutions containing 35% ethyl alcohol (v/v), 500 mg L⁻¹ citric acid and finally 200 mg L⁻¹ sulphur dioxide. In conclusion, sunflower seedlings can be considered a potential and interesting plant source of PPO. Sunflower PPO could be used to oxidise selectively o-diphenols, for example in alcoholic and nonalcoholic beverages.     

Partial characterization of polypeptide components of sunflower (Helianthus annuus L.) seed albumin fraction

The albumin fraction of sunflower seed (Helianthus annuus, cv. Mirasol) is a family of water soluble basic polypeptides which constitutes about 20% of the seed proteins. This fraction, isolated by selective isoelectric precipitation of globulins, has been studied in detail by sodium dodecyl sulphate gel electrophoresis, non equilibrium pH gradient electrophoresis and combination of these techniques using non reducing and reducing conditions. The molecular mass of the main polypeptides was markedly different between unreduced (12,000 to 16,500 g · mol^?1) and reduced form (10,000 to 18,000 g · mol^?1). As shown by NEPHGE mobility of these polypeptides was also altered by reduction. From these results and other observations is concluded that the stability of the globular structure of some polypeptides is dependent on the presence of intact disulphide crosslink(s). By multidimensional gel electrophoresis it was shown that the polypeptide components of each molecular mass classes displayed a high heterogeneity in net charge. Thus ion exchange chromatography procedures allowed only partial separation of different polypeptidic groups. Their amino acid composition shows that some of these fractions are, on the basis of their lysine and sulphur containing amino acids, of nutritional interest.     

Studies of the physico-chemical properties and polyphenoloxidase activity in seeds from hybrid sunflower (Helianthus annuus) varieties grown in India

Physico-chemical properties and polyphenol oxidase (PPO) activities of seven hybrid sunflower varieties commonly grown in Punjab state of India were studied. Seeds were studied for variations in physico-chemical properties, 100 kernel weight, density, bulk density, moisture, hull, oil, protein and ash content; expelled cake was studied for moisture, oil, crude fibre, ash and protein content and expelled-defatted cake for acid detergent fibre, lignin, moisture, ash and protein contents. PPO activity in all varieties, determined using pyrogallol as substrate at pH 6.5, varied between 0.212 and 0.294 Ab/min/mg protein. The PPO enzyme activity for MSFH-8 and Mega-363 was observed to be maximum at 55 and 60°C, respectively. The enzyme showed a K_m value between 1.01 and 1.968 mM for pyrogallol and V_max value between 0.21 and 2.0 Ab/min. ©     

Effects of irrigation water quantities and seasonal variation on oil content and fatty acid composition of sunflower (Helianthus annuus L.)

A field experiment was conducted in the North Western Group of the Gezira Scheme (longitude 32°48′ and latitude 15°14′) for four successive seasons, two winter and two summer seasons, during the years 1999–2002, to study the effect of different irrigation water quantities (300, 400, 500, 600 and 700 mm per season) on oil content and oleic acid and linoleic acid percentages in two sunflower cultivars [Rodeo, an open‐pollinated variety, and Hysun33, a hybrid). The experiment was designed in a split plot design, with four replicates. The cultivars were allotted to the sub‐plots while the irrigation treatments were assigned to main plots. The results showed that different irrigation water quantities had significant effects on all parameters studied and the cultivar Hysun33 gave a higher oil content (36.6%) at 700 mm whereas the open‐pollinated variety Rodeo gave 34.1% oil at that level of irrigation. The overall percentages of oleic and linoleic acids were 29.7 and 58.1 in winter and 47.6 and 43.1 in summer, respectively. Copyright © 2007 Society of Chemical Industry     

Production and characterization of sunflower (Helianthus annuus L.) protein-enriched products obtained at pilot plant scale

Sunflower protein concentrates with different content of phenolic compounds were produced at pilot plant scale from the by-product of oil manufacturing. The products obtained were characterized, and their physicochemical properties (i.e. surface hydrophobicity, thermal stability, and polypeptide composition) were evaluated at different storage conditions. All the procedures evaluated resulted in sunflower protein concentrates with high protein solubility (>60%) but with different chemical composition, color, and physicochemical properties. The products exhibited intense coloration and antioxidant properties due to their residual phenolic compounds content. The addition of an isoelectric precipitation step increased the protein content and the removal of phenolic compounds. The resulting concentrates exhibited high protein digestibility in vitro, even in the presence of phenolic compounds, and maintained high protein solubility for at least 6 months of storage. During this period, only structural changes in proteins were observed, as evidenced by their surface hydrophobicity. The results demonstrate that it is feasible to produce sunflower protein concentrates with high solubility on a pilot plant scale, using sunflower oilcake as starting material.     

Some physico‐chemical characteristics of honeys produced from sunflower plant (Helianthus annuus L.)

This study was conducted to determine the physico‐chemical characteristics of honeys (n = 52 samples) produced from sunflower in Trakya region of Turkey. We have evaluated the conformity of the honeys in accordance with the criteria specified by the Turkish Honey Standard (TS 3036), Turkish Food Codex and European Union Commission. According to the results of our analysis, the average values determined were in Tekirdag (n = 10 samples), Malkara (n = 22 samples), Hayrabolu (n = 13 samples) and Muratl? (n = 7samples) respectively: 6.67%, 6.06, 8.43, 7.89 for hydroxymethyl furfural (HMF); 15.02, 23.98, 18.61, 17.61 (Goethe unit) for diastase activity; 2.01%, 2.39, 2.36, 1.69 for saccharose; 75.26, 73.78, 75.50, 76.80 for invert sugar (%); 23.38, 34.92, 31.70, 26.38 for meq kg^?1 for acidity; 0.16, 0.25, 0.31, 0.13 for ash value (%); 18.13, 18.21, 17.52, 18.21 for water content (%).     

Saponin content of soya beans and some commercial soya bean products

Quantitative thin layer chromatography has been used to estimate the saponin content of whole soya beans (Glycine max L. Merrill, cv. Williams) and a number of commercial soya bean products such as protein isolates and lecithin. Saponins were present in all these materials at concentrations ranging from 56 g kg-¹ (on a dry weight basis) for whole soya beans to 3 g kg-¹ for the protein isolate ?Promine-D’?. Previous estimates indicate a saponin content of whole soya beans of only about 5 g kg-¹. It is suggested that this is an underestimate resulting from loss of material during the extraction procedures used in earlier methods of analysis.     

Distribution and biochemical composition of large and small seeds of soybean (Glycine max L.)

BACKGROUND: The position of soybean seeds on the stem axis brings about differences in seed filling during seed development, which contributes to different seed size and results in determining the quality of seeds for food usage. The quality differences between the large and small seeds are reported. RESULTS: The proportion of large seeds was higher at the apical portion while small seeds predominated at the basal portion of the soybean stem axis. The contents of lipids, starch, soluble sugars and soluble proteins were higher in large seeds as compared to those in small ones. The proportion of membrane lipid components, on a 10‐kernel basis, was higher in large seeds. The proportion of palmitate and oleate was also higher in large seeds. SDS‐PAGE analysis showed that glycinin (11S) proteins of 46 and 32 kDa were at higher concentrations, while 158 and 20 kDa were at lower concentration in large seeds in comparison to small seeds. Likewise, β‐conglycinins (7S) of 75, 62 and 46 kDa were higher in large seeds compared to small ones. CONCLUSION: Segregating the seeds of apical from the basal portion of soybean plant at harvest is expected to improve the germination, growth, yield and food‐processing aspects. Copyright © 2007 Society of Chemical Industry     

Nutritional evaluation of Zambia indigenous soy bean ( Glycine max) and sunflower (Helianthus annus) as protein sources in poultry and pigs diets

Two trials were carried out to compare the nutritional values of two Zambian indigenous plant protein sources — soy bean cake (SBC) and sunflower meal (SFM) in the diets of broilers and growing pigs. In trial 1, 120 one week old chickens (Abbor acre strain) were used. There were no differences (P > 0.05) between chickens on SBC and SFM in voluntary feed intake. Average daily gain of SBC chickens dif-fered (P < 0.05) from those of SFM. The protein source had an effect (P < 0.05) on N retained [g/day]. Carcasses dry matter and crude pro-tein were higher (P < 0.05) in SBC chickens, but ash, ether extract, Ca and P were the same as SFM. In trial 2, 12 Large white × Landrace growing barrows 1 — 2 months old were used. In this trial, SBC diet was consumed more than SFM. Pigs on SBC and SFM gained 0.526 and 0.284 g/head/day, respectively (P < 0.05). Nutrient digestibility was higher (P < 0.05) in SBC diet. Trial 1, demonstrated that SBC and SFM could be used for broilers without adverse effect on growth rate and body conformation. However, for growing pigs SBC is a better protein source than SFM in the tropical environment of Zambia. Finally, results obtained seem to suggest that SBC and SFM can be used as plant protein sources, but SFM is not an ideal plant protein source for growing pigs.     

Changes in differently processed soya bean (Glycine max.) and lima bean (Phaseolus lunatus) with particular reference to their chemical composition and their mineral and some inherent anti-nutritional constituents

The effects of 3 processing techniques: cooking, roasting and autoclaving on the proximate chemical composition, the mineral content and some inherent toxic factors of soya and lima beans were investigated. The processing techniques generally reduced the crude fibre levels and enhanced the extractable fat in the soya and lima beans. The coefficients of variability for crude fibre and ether extract due to the processing techniques of soya and lima beans were 20.9%, 16.0% and 22.3%, 38.1%, respectively. In parallel with decreased ash content in the cooked bean samples, there was a decrease in the K, Mg, Na and P levels relative to the raw bean and also relative to the other processing techniques. Mineral contents of the autoclaved bean samples were generally similar to those of the raw (unprocessed) samples. Under the processing conditions, roasting caused the highest reduction in thioglucoside content (59%) in soya bean while cooking caused the highest reduction in lima bean (78%). Trypsin inhibitor activity (TIA) ranged between 0.59 mg/g sample in the cooked soya bean and 11.6 mg/g sample in the raw bean while the corresponding values for lima bean ranged between 0.59 and 6.3 mg/g sample. Cooking and roasting caused over 90% reduction of TIA, while autoclaving caused 64-69% reduction in both bean samples. Under the assay conditions, haemagglutinating activity was not detected in the cooked and autoclaved soya and lima beans. The need to prevent both functional and nutritional damage to food proteins and other nutrients, resulting from excessive heating, was discussed.     

Change in isoflavone concentration of soybean (Glycine max L.) seeds at different growth stages

This study was conducted to determine the fluctuating levels of isoflavone in soybean (Glycine max L.) seeds of six varieties at different development stages. The average concentration of total isoflavone in the fully matured seed was 669 µg g^?1, whereas those in the seeds of the R5 (beginning), R6 (green full‐sized) and R7 (onset of physiological maturity) stages were 145, 296 and 611 µg g^?1, respectively. Sowonkong variety was highest in total isoflavone content of the fully matured and the R7 seed among all the varieties. In all six varieties, total isoflavone levels at the R7 stage were higher than those of R5 and R6 stages. Total isoflavone concentrations rapidly increased as growth stages transitioned from R5 to R7, as indicated by a positive correlation (r = 0.80***) between the total isoflavone and growth stages. Overall, total isoflavone levels were similar between R7 and the full maturity stages. Of the various isoflavone derivatives, acetylglucoside and aglycon were not significantly correlated with total isoflavone concentrations. However, glucoside (r = 0.97***), malonylglucoside (r = 0.99***), TGIN (genistein + genistin + malonylgenistin + acetylgenistin, r = 0.93***) and TDIN (daidzein + daidzin + malonyldaidzin + acetyldaidzin, r = 0.99***) were very highly correlated with total isoflavone concentrations. As a result, they constituted most of the total isoflavones in the soybean seeds at R5, R6, R7, and full maturity stages. Copyright © 2007 Society of Chemical Industry     

Non‐digestible carbohydrates in Brazilian soybean seeds [Glycine max (L.) Merril]

Non‐digestible carbohydrate fraction (NDCF) consists of a range of bioactive compounds that escape digestion in the small intestine. NDCF is mainly composed of dietary fibre (DF) and non‐digestible oligosaccharides (NDO). The objective of this work was to analyse directly and compare the NDCF in two Brazilian cultivars of soybean seed with commercial flour. Brazil is the second major soybean producer in the world. The seed cultivars showed on average a NDCF value of 32.80 g per 100 g dry weight (dw). Regarding DF, insoluble DF (IDF) was the main fraction amounting on average to 98%. Uronic acids were significantly higher than neutral sugar (NS) in IDF and soluble DF (SDF) fractions. There was a considerable amount of Klason lignin – on average 84.14% of DF. Regarding NS profile, mannose was the most important sugar in SDF, whereas galactose and arabinose were predominant in IDF. Stachyose was the main oligosaccharide in NDO. DF and NDO were in the same proportion (94.2:5.8) in tested cultivars. No differences in swelling, water retention, or oil retention capacities between seed cultivars were detected. This study on non‐digestible carbohydrate components in soybean seed gives a different approach to the current nutritional knowledge on protein and oil constituents.     

Chemical composition,digestibility and protein quality of 12 sunflower (Helianthus annuus L) cultivars

Twelve sunflower (Helianthus annuus L) cultivars grown in Spain were analysed and tested in experiments with rats. The dehulled seeds contained an average of 32.2 MJ kg⁻¹ dry matter (DM) gross energy, 653 g kg⁻¹ DM fat, 60 g kg⁻¹ DM total non-starch polysaccharides (NSP) and 6 g kg⁻¹ DM Klason lignin. The sunflower seed hulls contained 20.2 MJ kg⁻¹ DM gross energy, 53 g kg⁻¹ DM fat, 562 g kg⁻¹ DM total NSPs and 239 g kg⁻¹ DM Klason lignin. The sunflower samples were dehulled and partially defatted (to ∼17% fat) and included in diets for rats. The dehulled, partially defatted samples contained on average 74.6 g nitrogen kg⁻¹ DM and 1.409 mg g⁻¹ phenolic compounds (chlorogenic acid + caffeic acid + derivative 1 + derivative 2) varying from 0.677 to 2.847 mg g⁻¹. Groups of five growing rats were fed diets (9.38% crude protein) containing one of the sunflower cultivars as the only source of protein. Apparent ileal and faecal digestibilities were determined by using an indigestible marker (Cr₂O₃) and faecal digestibility based on total faecal collections. Apparent ileal, caecal and faecal digestibilities of organic matter were 81.2–91.5% (P = 0.05), 95.8–97.1% (P = 0.005) and 94.7–95.3% (P = 0.94) respectively. The apparent faecal digestibilities of DM, energy and protein (N × 6.25) were 93.2–93.8%, 93.5–94.3% and 81.6–84.3% respectively with no differences among cultivars. Biological value (BV) ranged between 63.8 and 73.2% (P = 0.0001) and net protein utilisation (NPU) between 59.9 and 69.5% (P = 0.0001). BV and NPU were positively correlated with lysine and threonine contents, but no correlation with the analysed phenolic compounds was detected. © 1999 Society of Chemical Industry     

Polyphenol Oxidase from Bean Sprouts (Glycine max L.)

ABSTRACT: Polyphenol oxidase (PPO) was purified and characterized from bean sprouts by ammonium sulfate precipitation, DEAE‐Toyopearl 650M, CM‐Toyopearl 650M, SuperQ‐Toyopearl 650S and QAE‐Toyopearl 550C column chromatographies. Substrate staining of the crude extract on electrophoresis showed the presence of 2 isozymic forms of this enzyme. The molecular weight of the purified enzyme was estimated to be about 54 kDa. The optimum pH was 9.0 and optimum temperature 40 °C. Heat inactivation occurred about 30 °C. PPO showed activity to catechol, pyrogallol and dopamine. These compounds such as ascorbic acid, L‐cysteine, 2‐mercaptoethanol, and glutathione used was the effective inhibitor. Enzyme activity was maintained for 7 d at 4 °C but suddenly decreased after 8 d.