Enrichment of Egyptian 'Balady' bread. Part 1. Baking studies, physical and sensory evaluation of enrichment with decorticated cracked broadbeans flour (Vicia faba L.)

Physical, rheological and baking properties of decorticated cracked broadbeans-wheat composite flours were studied and the acceptability of the Egyptian 'Balady' bread was evaluated by sensory tests. Decorticated cracked broadbeans flour (DCBF) was used to replace 5%, 10%, 15% and 20% of the wheat flour (WF) in bread. Farinographic studies showed that water absorption, arrival time and dough development time increased as the amount of DCBF increased, while dough stability time increased at 5% and 10% of DCBF substitution and decreased at 15% and 20% substitution. Also, the extensographic energy of the dough decreased as DCBF substitution increased, while the ratio between resistence and extensibility increased. There was a decrease in peak viscosity with increased amounts of DCBF. A reduction of the diameter and weight of bread loaf was observed as the amount of DCBF increased. The sensory properties of 'Balady' bread showed that at the two levels of 5% and 10% DCBF-substitution, the 'Balady' loaves did not show any significant differences (P > 0.05). It is concluded that the replacement of bread flour (WF) with up to 10% decorticated cracked broadbeans flour produced acceptable Egyptian 'Balady' bread.     

Enrichment of Egyptian ‘Balady’ bread. Part 2. Nutritional values and biological evaluation of enrichment with decorticated cracked broadbeans flour (Vicia fabaL./ 1

Decorticated cracked broadbeans flour (DCBF) was used to replace 5%, 10%, 15% and 20% of the wheat flour (WF) in the Egyptian ‘Balady’ bread. The nutrient composition of DCBF, WF, wheat bread, and DCBF‐fortified bread was studied. When DCBF fortification was increased from 0 to 20%, there was an increase of 36% in protein, 18% in fat, 123% in calcium, 52% in phosphorus and 40% in iron contents. DCBF contained greater amounts [g/16 g N] of lysine and histidine compared to WF. All essential amino acids increased when DCBF was substituted for WF from 0 to 20%, except methionine, which decreased. The biological quality of the breads was investigated. The protein efficiency ratio for 10%. DCBF bread (1.60) was found to be significantly greater (P > 0.05) than that of 5%‐DCBF bread (1.48) and wheat bread (1.17).     

Enrichment of Egyptian 'Balady' bread. Part 2. Nutritional values and biological evaluation of enrichment with decorticated cracked broadbeans flour (Vicia faba L.)

Decorticated cracked broadbeans flour (DCBF) was used to replace 5%, 10%, 15% and 20% of the wheat flour (WF) in the Egyptian 'Balady' bread. The nutrient composition of DCBF, WF, wheat bread, and DCBF-fortified bread was studied. When DCBF fortification was increased from 0 to 20%, there was an increase of 36% in protein, 18% in fat, 123% in calcium, 52% in phosphorus and 40% in iron contents. DCBF contained greater amounts [g/16 g N] of lysine and histidine compared to WF. All essential amino acids increased when DCBF was substituted for WF from 0 to 20%, except methionine, which decreased. The biological quality of the breads was investigated. The protein efficiency ratio for 10%. DCBF bread (1.60) was found to be significantly greater (P < 0.05) than that of 5%-DCBF bread (1.48) and wheat bread (1.17).     

Effects of polyphenol oxidation on in vitro iron availability in faba bean (Vicia faba L.) flour

Tannic acid (TA) and green tea extract (GTE) were added to faba bean flour, before and after incubation with polyphenol oxidase (mushroom tyrosinase), and the effect on in vitro iron availability was investigated. The inhibitory effect of TA and GTE was dose dependent, and the in vitro iron availability decreased from 64.5% in the pure faba bean flour to 9.8% (P < 0.05) with the addition of 1 mg of TA 1 g^?1 to faba bean flour. The addition of 5 mg of GTE resulted in low in vitro iron availability as after the addition of 10 mg of TA (11.6% against 10.3% for 1 mg TA). Incubation of the polyphenols with tyrosinase before addition to the faba bean flour significantly increased the in vitro iron availability. The increase in iron availability was significant (P < 0.05) when amounts of 0.2, 0.5 or 1 mg g^?1 TA or GTE added to faba bean flour, respectively, were oxidised, even with the lowest amount of tyrosinase (150 u). Oxidation of 1 mg TA or GTE with 150 u tyrosinase increased the in vitro iron availability from 10.3% to 15.5% and from 19.2% to 26.1%, respectively. At the 300‐u level, the addition of higher amounts of enzyme (from 600 to 900 u) did not have any effect. The results from the study therefore suggest that the oxidation of polyphenols may be a promising way to increase the availability of iron in polyphenol‐containing legume foods.     

Preparation of broad bean (Vicia faba L. minor) products Part 3. Pretreatment of broad beans and broad bean flour —processes and effects

For improving sensory, functional and other properties broad beans are pretreated in 3 different ways. The pretreatments include defatting or isoelectric washing of broad bean flour and hydrothermal treatment of whole dehulled broad beans. Every pretreatment process leads to particular advantages, described in this paper, although sensory improvements are found in all pretreated products.     

In vitro starch digestibility of fresh and sun‐dried faba beans (Vicia faba L.)

Fresh and sun‐dried faba beans (Vicia faba L.) were cooked, stored for various times at 4 °C and analysed for available starch (AS), resistant starch (RS) and fibre‐associated resistant starch (FARS) contents as well as α‐amylolysis. Fresh beans required a shorter cooking time (25 min) than dried beans (158 min). Cooked fresh faba beans had a higher AS content than cooked dried faba beans. The AS content in both decreased during cold storage, with fresh beans showing a smaller decrease than dried beans with increasing storage time. Cooked fresh faba beans also had a higher total RS content than cooked dried faba beans, although a greater increase in RS content was recorded in the latter upon storage. Starch retrogradation was more prominent in cooked dried faba beans than in cooked fresh faba beans, as indicated by the consistently higher FARS content. The α‐amylolysis rate decreased with increasing storage time, i.e. long‐stored (72 h) cooked faba beans exhibited slower starch digestion, and differences were recorded between fresh and dried beans. The predicted glycaemic index ranged between 60.9 and 58.0% for cooked fresh faba beans and between 57.9 and 55.8% for cooked dried faba beans, which is suggestive of slow glucose release from starch in faba beans. Copyright © 2007 Society of Chemical Industry     

NaOH treatment reduces capsaicin content and pungency of ‘Makedoniko’ pepper (Capsicum annuum L.)

Pickled peppers are preferred by certain consumer groups at reduced pungency. To investigate the reduction in pepper pungency and capsaicin content, fresh ‘Makedoniko’ hot peppers were treated with 0, 0.5 or 1% NaOH before preserved in acid brine for 60 days. Pepper physicochemical traits were monitored following NaOH treatment and during preservation. Capsaicin content was measured in the beginning and at the end of preservation, and the peppers were also tested organoleptically. Preservation in acid brine induced the typical green–yellow product colour, increased firmness and decreased the dry mass in all treatments. NaOH‐treated pepper increased phenolics, chlorophyll and antioxidant content in dry mass during preservation faster than the control. Capsaicin content was reduced by 25 or 50% following 0.5 or 1% NaOH treatment, respectively. Pepper organoleptic pungency was also decreased following 1% NaOH treatment. NaOH reduces capsaicin content and pungency of ‘Makedoniko’ pepper, with minor effects on its processed product quality.     

Effects of cultivar and culture conditions on γ‐aminobutyric acid accumulation in germinated fava beans (Vicia faba L.)

BACKGROUND: High levels of γ‐aminobutyric acid (GABA) accumulate in plant tissues under various stresses. GABA accumulation is also influenced by cultivar. This aim of this study was to select the most promising cultivar of fava bean for GABA accumulation and to optimise the culture conditions for GABA production in germinated fava beans by response surface methodology based on central composite design (CCD). RESULTS: GABA content and glutamate decarboxylase activity in germinated seeds of cultivar S2 were significantly higher than those in other cultivars (P < 0.05). A significant negative correlation (r = −0.765, P < 0.05) between germination percentage and 1000‐kernel weight was observed. There was a linear relationship between GABA content and sprout length (R² = 0.816). The regression model fitted to the experimental data of CCD was valid in predicting GABA production in germinated fava beans. Temperature and pH value of the culture solution had significant effects on GABA content in germinated fava beans. Under optimal culture conditions (33.6 °C, pH 3.19 and an air flow rate of 1.19 L min⁻¹), GABA content reached up to 2.41 g kg⁻¹ dry weight, about 48 times that in raw seeds. CONCLUSION: Germinated fava bean is a good resource of GABA‐rich food. Both cultivar and culture conditions have significant effects on GABA production. Copyright © 2009 Society of Chemical Industry     

Cultivar identification of Vicia faba (L.) by sodium dodecyl sulphate–polyacrylamide gel electrophoresis of seed globulins

The globulin fraction isolation from Vicia faba seeds of different cultivars and different lines of the same cultivar has been examined by sodium dodecyl sulphate-poly-acrylamide gel electrophoresis (SDS-PAGE). The technique separates the globulin polypeptides into three distinct groups, termed A, B and C, with molecular weights above 46 kD, between 30–40 kD and below 26 kD, respectively. Distinct differences between polypeptide patterns of the different cultivars and of the different lines of the same cultivar were observed in groups A and B, little variation occurred in group C. Gradient zonal isoelectric precipitation was used to separate the globulin fraction of different cultivars into vicilin and legumin. Variation in polypeptide composition between cultivars was observed in both vicilin and legumin following SDS-PAGE. No difference between cultivars was detected in group C polypeptides of legumin.     

Postharvest response of ‘Brown Turkey’ figs (Ficus carica L.) to the inhibition of ethylene perception

The potential use of 1‐methylcyclopropene (1‐MCP) alone or as a supplement to cold storage to delay the softening of ‘Brown Turkey’ figs (Ficus carica L.) was studied. Figs were treated with 0, 0.25, 0.5 or 5 µl l^?1 1‐MCP at 25 °C for 8 h and stored at 20 °C until evaluated. Figs treated with 0.5 or 5 µl l^?1 1‐MCP had higher ethylene production and respiration rates but slower softening than untreated fruit and those treated with 0.25 µl l^?1 1‐MCP. Early‐harvested firm figs and late‐harvested soft figs were untreated or treated with 0.5 or 5 µl l^?1 1‐MCP at 25 °C and stored at 0 °C for 19 days. Firm figs treated with 1‐MCP showed an early peak in ethylene synthesis, higher respiration rate and were firmer than control fruit. In contrast, soft figs did not respond to 1‐MCP except for a late increase in respiration rates of fruit treated with 5 µl l^?1 1‐MCP. 1‐MCP appeared to have a relatively limited effect on slowing ripening of ‘Brown Turkey’ figs and its effect was influenced by ripening stage. Copyright © 2005 Society of Chemical Industry     

Preparation of broad bean (Vicia faba L. minor) products. Part 2. Broad bean protein isolates from seed flour in the pH range below the isoelectric point

Broad bean protein isolates in aqueous solutions form stable gels after heating at pH values below the isoelectric point (pH 2-3) if they are extracted at the same pH. But the acid extraction is a time-consuming and expensive process. This paper outlines a new and simple procedure for the preparation of broad bean protein isolates in the acid pH range. It consists of a short extraction of seed flour at pH 7.5 (30 min) followed by an after-treatment at pH 2-3 (60 min) and gives the highest yield of acid treated broad bean protein isolates after a sudden acidification.     

Preparation of broad bean (Vicia faba L. minor) products Part,I. Broad bean protein isolates from seed flour and their acetylation in the neutral pH range

It is possible to prepare broad bean protein isolates with a high yield directly from seed flour using a wet process. This process involves an aqueous extraction at pH 7.5 followed by separation of the insoluble residue and isoelectric precipitation of the protein from the aqueous extract. Following the same principle is it possible to prepare acetylated broad bean protein isolates with any adjustable acetylation degree. For that acetic anhydride is to be added and the adjusted pH is to be maintained during the extraction. In both cases the yield of the protein is mainly determined by the used solid-liquid ratio.     

Hydrolysis of the toxic constituents (vicine and convicine) in fababean (Vicia faba L.) food preparations following treatment with β-glucosidase

Several experiments were carried out to determine whether the concentrations of vicine and convicine in fababean food preparations were reduced following heat and β-glucosidase treatment. Heating fababeans to relatively high temperatures was not effective in reducing the concentration of these glycosides. Treatment of cooked fababeans (fababean paste) with ground raw almond powder, which is a rich source of β-glucosidase (EC 3.2.1.21) activity, resulted in the hydrolysis of vicine and convicine. The degree of hydrolysis ranged from partial to complete and was dependent on the duration of the treatment period (1 to 24 h), the temperature at which treatment was carried out (1 to 30°C), the pH (6.4 to 4.6) as adjusted by the addition of lemon juice and the amount of ground almonds added to the fababean paste. For example, 88 to 89% of the glycosides were hydrolysed when 1 g of fababean paste was mixed with 0.1 g of almond powder and 0.1 ml of lemon juice and incubated at 30°C for 3 h. This study demonstrated that the concentration of vicine and convicine and their corresponding aglycones can be greatly reduced in fababean food preparations by enzymic hydrolysis.     

Antioxidative enzyme activity and internal browning of 1‐methylcyclopropene‐treated European pear fruits (cv. ‘Shahmiveh’ and ‘Sebri’)

The effects of 1‐methylcyclopropene (1‐MCP) on antioxidative enzyme and internal browning (IB) incidence of two European pear cultivars ‘Shahmiveh’ and ‘Sebri’ stored at 0.5 °C were investigated. Ethylene production of ‘Sebri’ was delayed by 1‐MCP but suppressed in ‘Shahmiveh’. IB increased in both cultivars, with a higher level of the incidence in ‘Shahmiveh’, and was reduced by 1‐MCP. Activities of catalase (CAT) and peroxidase, but not superoxide dismutase (SOD), decreased in untreated fruit during the first 40 days. 1‐MCP had little effect on SOD activity or on total phenolics. Polyphenoloxidase activity did not increase over time in 1‐MCP‐treated fruit of the IB sensitive ‘Shahmiveh’, and the effect was inconsistent for ‘Sebri’. Ascorbic acid (AA) levels in 1‐MCP‐treated fruit of both cultivars declined at a lower rate compared with untreated fruit during storage, but the reduction in AA levels was faster in ‘Shahmiveh’ compared with ‘Sebri’. Also, the effects of 1‐MCP on antioxidative systems may be related to IB development.     

Fractionation of plant material. IV.—Distribution of amino acid residues in fractions obtained from leaves of broad bean (Vicia faba L.)

The quantitative distribution of amino-acid residues amongst some fractions derived from broad-bean leaves was determined. Among the free amino acids, asparagine predominated and 3,4-dihydroxyphenylalanine (DOPA) was abundant. DOPA was absent from the protein fractions. Aggregated N recovery and amino acid composition resembled those found for leafy materials by previous workers. Material extracted by ethanol from the TCA-precipitated fraction resembled the bulk protein in molecular size and amino acid composition. A fraction not migrating during electrophoresis in phenol-acetic acid-water gave, on hydrolysis, amino acids presumed to be bound in neutral or weakly acid compounds, mostly of low molecular weight.     

CHANGES IN QUALITY CHARACTERISTICS DURING PEACH (CV. ‘MAJESTIC’) MATURATION1

Changes in the physical, chemical and sensory characteristics of peaches (cv. ‘Majestic’) were determined. Size, weight, ground color “a” values and SS/TA ratio increased significantly with increased degree of maturity; whereas, firmness, DLE, hue angle, titratable acidity, quinic acid, and citric acid decreased significantly. Malic acid increased significantly with maturity up to grade 5 then significantly decreased. In general sucrose content and total sugars increased through grade 6 and then decreased for tree ripe fruit. Sensory evaluation results showed no significant differences among maturity grades for sweet, sour, juice and overall peach flavor attributes. However, grade 1 and 2 fruit had lower scores for sweet and overall peach flavor attributes and tended to be more sour than grades 3–6 and tree ripe fruit. Correlation coefficients between maturity grade and all the selected quality parameters, except for the sour flavor attribute, were significant at the 1% level. DLE had the highest correlation with maturity grade followed by ground color “a” value, SS/TA ratio and firmness.     

Fractionation of plant material II.—Amino acid composition of some fractions obtained from the broad bean plant (Vicia faba L.) and chromatographic differentiation of hydroxyproline isomers

The amino acid compositions of three protein fractions obtained from broad bean leaves were estimated by ion exchange chromatography. Hydroxyproline was found present in the TCA-soluble, non-diffusible fraction and in the final residue after the further extraction with phenol-acetic acid-water (2: 1 : 1, w/v/v), but not in the extract itself. By comparison with the behaviour of four authentic isomers of hydroxyproline, under two standard conditions of chromatographic analysis, the isomer found was trans-4-hydroxy-proline. These results are discussed in relation to other reports of hydroxyproline occurring in plant material.