Total phenolic content and antioxidant properties of eclipse black beans (Phaseolus vulgaris L.) as affected by processing methods

ABSTRACT:  The effects of soaking, boiling, and steaming processes on the phenolic components and antioxidant activity of black beans were investigated. All processed beans exhibited significantly ( P < 0.05) lower antioxidant activities than raw beans in total phenolic content (TPC), DPPH free radical scavenging activity (DPPH), and oxygen radical absorbing capacity (ORAC). Steaming processes resulted in a greater retention of TPC and ORAC values than the boiling processes. Pressure boiling shortened processing time compared to regular boiling, resulted in insignificant differences in TPC, but significantly increased in ORAC as compared to the regular boiling method. Pressure steaming resulted in significant decreases in TPC, DPPH, while significantly increased in ORAC compared to regular steaming. Greater TPC, DPPH, and ORAC values were detected in boiling water than in the soaking and steaming water. Mass balance analysis showed that boiling caused more dry solid loss than steaming. All of these results indicated that processing methods significantly changed contents and activities of antioxidant components of black beans. Steam processing exhibited several advantages in appearance and texture of the cooked product, shortening processing time, and in greater retention of TPC and antioxidant activities. Steam processing may be used to develop high-quality health-promoting black bean products.     

Polyphenols content and antioxidant capacity of thirteen faba bean (Vicia faba L.) genotypes cultivated in Tunisia

In vitro antioxidant capacity of thirteen genotypes of faba bean (Vicia faba L.) collected during three different growing stages (vegetative, reproductive and maturity) have been evaluated. For the vegetative stage (VS) and reproductive stage (RS) the whole plant (WP) has been used for the analysis while for the maturity stage (MS) the plant was divided and analyzed in different parts, the whole seed (WS), seed coat (SC), cotyledons (Cot) and pod (Pod). The antioxidant capacity has been evaluated by means of the total phenolic and total flavonoid contents (TPC and TFC respectively), the ferric-reducing/antioxidant power (FRAP) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assays. The results showed different antioxidant properties for the same genotype when considering the different parts or stages of the plant. High content of both total phenolics (> 92.85 mg as gallic acid equivalent (GAE)/g of dried plant) and flavonoids contents (> 11.87 mg as rutin equivalent (RE)/g of dried plant) were found for all genotypes during the vegetative and the reproductive stages, which also showed the highest antioxidant activity (FRAP value ≥ 1.157 mmol/g and DPPH radical-scavenging capacity > 43.49%), indicating their potential as natural sources of antioxidant foods. For the maturity stage, the highest values for the TPC, TFC, FRAP and DPPH scavenging capacity were observed for the pods and the lowest for the cotyledons.The results of this study indicate that faba beans are a good source of natural antioxidants independently to their genotype. The quantification of the antioxidant capacity according to the stage and the plant part could be suitable for applications on the food industry in relation to production and preservation of faba bean food products.     

Reduction of antiproliferative capacities,cell-based antioxidant capacities and phytochemical contents of common beans and soybeans upon thermal processing

The effects of boiling and steaming processes on the antiproliferative and cellular antioxidant properties, as well as phytochemicals, of two types of common beans (pinto and black beans) and two types of soybeans (yellow and black) were investigated. All thermal-processing methods caused significant (p < 0.05) decreases in total phenolic content (TPC), total saponin content (TSC) and phytic acid content (PAC) values in all bean types (except for TPC values in pressure-steamed yellow soybeans) as compared to those of the raw beans. All types of uncooked raw beans exhibited cellular antioxidant activities (CAA) in dose-dependent manners. Black soybeans exhibited the greatest CAA, followed by black beans, pinto beans and yellow soybeans. The CAA of cooked beans were generally diminished or eliminated by thermal processing. The hydrophilic extracts from raw pinto beans, black beans and black soybeans exhibited antiproliferation capacities against human gastric (AGS) and colorectal (SW480) cancer cells in dose-dependent manners. The raw yellow soybeans exhibited dose-dependent antiproliferation activities against the SW480 cells. Most of the cooked beans lost their antiproliferation capacities as observed in the raw beans. These results indicate that different processing methods may have various effects on phytochemical profiles and bioactivities. Overall, thermal processing caused a significant reduction of the health-promotion effects of beans.     

Use of low-temperature extrusion for reducing phytohemagglutinin activity (PHA) and oligosaccharides in beans (Phaseolus vulgaris L.) cv. Navy and Pinto

Bean (Phaseolus vulgaris L.) lectins and oligosaccharides are the anti-nutrients that limit dry bean consumption. The objective of this study was to study the effects of low temperature (85 °C) extrusion and steam-cooking (82 °C) on the fate of lectin, analysed as phytohemagglutinin activity (PHA), and the oligosaccharides, raffinose and stachyose. Both extrusion processing and steam-cooking significantly (p ? 0.05) reduced the lectin in bean flour by 85–95% over raw bean flours (control). The stachyose content in extruded navy bean flours was comparable to that in raw and steam-cooked flours while extruded pinto bean flour had significantly lower stachyose content than that found in raw and steam-cooked flour. The raffinose content of both navy and pinto extruded flours, though lower than raw bean flours, was significantly higher than that in steam-cooked flours. The results of this study demonstrated that extrusion processing at relatively lower temperature can be effective in eliminating lectins and reducing oligosaccharides.     

Effect of cooking and germination on phenolic composition and biological properties of dark beans (Phaseolus vulgaris L.)

Legumes are the base´s diet in several countries. They hold a high nutritional value, but other properties related to human health are nowadays being studied. The aim of this work was to study the influence of processes (boiling or germination) on the phenolic composition of dark beans (Phaseolus vulgaris L. c.v. Tolosana) and their effect on their antioxidant, neuroprotective and anticancer ability. Phenolic composition of raw and processed dark beans was analysed by HPLC-PAD and HPLC–ESI/MS. The antioxidant activity was evaluated by ORAC. Astrocytes cultures (U-373) have been used to test their neuroprotective effect. Anticancer activities were evaluated on three different cell lines (renal adenocarcinoma (TK-10), breast adenocarcinoma (MCF-7) and melanoma (UACC-62)) by sulphorhodamine B method. Qualitative and quantitative differences in phenolic composition have been observed between raw and processed dark beans that influence the antioxidant activity, mainly for germinated samples which show a decrease of antioxidant capacity. Although every assayed extracts decreased reactive oxygen species release and exhibited cytotoxicity activities on cancer cell lines, raw beans proved to be the most active in neuroprotective and antitumoral effects; this sample is especially rich in phenolic compounds, mainly anthocyanins. This study further demonstrated that phenolic composition of dark beans is related with cooking process and so with their neuroprotective and anticancer activity; cooking of dark beans improves their digestion and absorption at intestinal level, while maintaining its protective ability on oxidative process at cellular level.     

Impact of household food processing strategies on antinutrient (phytate,tannin and polyphenol) contents of chickpeas (Cicer arietinum L.) and beans (Phaseolus vulgaris L.): a review

Pulses, which include beans and chickpeas, are major constituents of the human diet. They are important sources of energy and nutrients, particularly protein, folate and minerals. However, they also contain antinutrients which bind minerals, mainly iron and zinc, rendering them less bioavailable or unavailable for absorption. The levels of these antinutrients may be reduced by food processing techniques such as soaking and germination. Researchers have used these techniques in a number of studies; however, there is no consensus regarding the optimum processing conditions for reduction in the levels of these antinutrients. Thus, this review was conducted to describe the results of studies on soaking and germination of chickpeas and beans. A systematic search was carried out utilising Food Science and Technology Abstracts (FSTA) (1969 to present), Web of Science (1899 to present) and Scopus (1823 to present). A total of thirty‐three articles were reviewed. Both soaking and germination resulted in significant but variable degrees of reduction in levels of antinutrients in most studies.     

Physico-chemical characterization of stored black beans (Phaseolus vulgaris L.)

Selected physical and chemical characteristics were studied on black beans (Phaseolus vulgaris L.) after 2 years of storage under refrigerated hypobaric conditions (RHC) and ambient conditions (AC). Black beans stored under RHC of 4.5°C, 50–60% relative humidity and atmospheric pressure of 125 mm Hg exhibited quality factors characteristic of fresh beans, such as shorter cooking time, smaller quantities of solids loss, electrolytes leached, and percentage of hardshell than beans stored at AC of 23–25°C and 30–50% relative humidity. Additionally, beans stored under RHC demonstrated greater germination rate (93%) than beans stored at AC (72%). Beans stored at AC exhibited quality factors characteristic of hard-to-cook (HTC) beans. Percentage water absorption indicated a faster initial hydration rate in beans stored under RHC compared to beans stored at AC until after 12 h of soaking, when both reached a similar hydration rate. Moisture content of beans stored under RHC was similar to that of beans prior to storage, while the moisture content of beans stored at AC was significantly lower. Crude protein, crude fat, and ash concentration of beans prior to storage and beans stored for 2 years under RHC or AC were not significantly different. The electrophoretic profile of the main protein of beans, globulin G1, was not altered by the storage conditions. The combined effect of refrigeration and hypobaric storage conditions demonstrated potential for maintaining the fresh quality of beans in storage for up to 2 years.     

Effect of pre-dehulling treatments on some nutritional and physical properties of navy and pinto beans (Phaseolus vulgaris L.)

The effect of pre-dehulling treatments using low and high temperatures on some nutritional and physical properties of navy and pinto beans was investigated. Beans were exposed to water (14%, 28% and soaking 1:5, w/v for 6 h, 16 and 16 h, respectively) to facilitate seed coat detachment prior to freeze drying (FD) for 48 h or heat drying (HT) for 20 or 60 min. Exposure to the highest moisture levels produced the largest seed coat yields (17.38-20.91%) and was independent of the drying conditions. The total phenolic content was positively correlated to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) antioxidant activity and increased as the exposure time to HT increased, but it was unaffected by the FD. The nutritional properties of the bean varieties differed significantly, phytic acid was unaffected, and the highest antioxidant activity was observed on the seed coats of HT pinto beans (69.24-84.46% of DPPH discoloration). Significant physical changes were observed for the HT seeds, with the highest yellowness and the lowest peak viscosity detected in the soaked and HT (60 min) beans.     

Phenolic contents and antioxidant activities of bitter gourd (Momordica charantia L.) leaf, stem and fruit fraction extracts in vitro

Bitter gourd (Momordica charantia L.) has long been regarded as a food and medicinal plant. We investigated the antioxidant activity of the water extract of leaf, stem and fruit fractions by several in vitro systems of assay, namely DPPH radical-scavenging activity, hydroxyl radical-scavenging activity, β-carotene–linoleate bleaching assay, ferric reducing/antioxidant power (FRAP) assay and total antioxidant capacity. Total phenolic content was measured by Folin–Ciocalteu reagent. Identification of phenolic compounds was achieved using HPLC with the UV-diode array detection. The extracts of different fractions were found to have different levels of antioxidant activity in the systems tested. The leaf extract showed the highest value of antioxidant activity, based on DPPH radical-scavenging activity and ferric reducing power, while the green fruit extract showed the highest value of antioxidant activity, based on hydroxyl radical-scavenging activity, β-carotene–linoleate bleaching assay and total antioxidant capacity. The predominant phenolic compounds were gallic acid, followed by caffeic acid and catechin. The present study demonstrated that the water extract fractions of bitter gourd have different responses with different antioxidant methods. Total phenol content was shown to provide the highest association with FRAP assay in this present study (R² = 0.948).     

The effects of various culinary treatments on the pigment content of green beans (Phaseolus vulgaris, L.)

The effects of four culinary treatments (steaming and boiling in a covered pot, a pressure cooker or a microwave oven) on the chlorophyll a and b, all-trans-lutein, phaeophytin a and b and all-trans-β-carotene (provitamin A) contents of green beans (Phaseolus vulgaris, L.) were evaluated. The pigments in the fresh and treated beans were determined by gradient elution reverse-phase HPLC with UV detection. Boiling the beans in a covered pot, pressure cooking or microwaving them caused smaller losses of pigments than steamed cooking. Since pressure cooking also generally leads to smaller losses of nutritious components (e.g. vitamin C), it is recommended over the traditional method of boiling beans in a covered pot.     

Protein and starch content of raw,soaked and cooked beans (Phaseolus vulgaris L.)

Organoleptic qualities are an important factor in the market value of legumes, especially in developed countries. Unfortunately, the molecules that have the greatest influence on the texture of beans undergo important transformations during soaking and cooking. Moreover, the extent to which these changes are linear is unknown, making uncertain the use of raw beans in chemical screenings for sensory properties. Results of our experiments show that the amount of protein and amylose present in raw beans provides a good indicator of these substances in cooked beans (correlation coefficients between raw and cooked beans = 0.91, p ? 0.001 and 0.87, p ? 0.01, respectively). The Mg content in the raw seed coat also shows a strong correlation with that found in the cooked seed coat (r = 0.86, p ? 0.01). The correlations found for the other traits are weaker, indicating that the evaluation of raw samples is not predictive of the findings in cooked beans.     

Studies on cocoa beans (Theobroma cocoa L.)

Summary Scanning electron microsopcy (SEM) was used to study the microstructure of raw and processed cocoa beans (Theobroma cocoa L.). Photomicrographs of seed coat revealed tracheary elements (spiral vessels) and simple pits, while the cotyledon of raw bean consists of parenchyma cells. When beans were roasted to 125 °C for 20 min, the cotyledon became porous and brittle and the cellular contents became thermally coagulated. Also, after basification there was an increase in surface porosity of the cotyledon. These SEM observations could be employed as a monitor for processing and/or quality control.The basification of cocoa beans with different alkalis, revealed differences in color as depending on the type of alkali and its concentration.

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Untersuchungen über Kakaobohnen (Theobroma cocoa L.)Einfluß einiger Verfahren auf die Mikrostruktur und Farbe der Bohnen

Zusammenfassung Scanning-Elektronenmikroskopie (SEM) wurde für die Untersuchung der Mikrostruktur roher und behandelter Kakaobohnen angewandt. Mikrophotographien der Samenschale zeigten Tracheenelemente (Spiralgefäße) und einfache Vertiefungen, während die Cotyledonen der rohen Bohnen aus Parenchymzellen bestehen. Wenn Bohnen für 20 min bei 125 °C geröstet werden, werden die Cotyledonen porös und brüchig und der Zellinhalt koaguliert. Auch nach der Alkalisierung erhöht sich die Porosität der Oberfläche der Cytoledonen. Diese SEM-Beobachtungen könnten zur Prüfung, der Arbeitsweise und/oder der Qualitätskontrolle angewandt werden. Die Alkalisierung der Kakaobohnen mit verschiedenen Alkalien zeigt Unterschiede in der Farbe in Abhängigkeit von der Art und Konzentration des Alkali.

     

Variability in the major lipid components of four market classes of dry edible beans

The lipid composition of dry edible beans (Phaseolus vulgaris L) was characterised and the variability between four US market classes (navy, dark red kidney, pinto and Black Turtle Soup) was determined. The total lipid content of the beans ranged from 1–8 to 2–6 g per 100 g dry weight. Triacylglycerol esterified sterified glucoside and phosphatidylcholine were identified as the major lipid class components of the neutral lipid, glycolipid and phospholipid fractions, respectively. The fatty acids were highly unsaturated: linolenic acid was the major fatty acid. Three sterols, campesterol, stigmasterol and β-sitosterol, were identified. The lipid and fatty acid contents of the bean classes were significantly ( P <0–05) different. Principal component analysis of the total lipid components resulted in the extraction of four factors, which accounted for 93.3% of the variability of the data set. These factors were characterised as the (I) fatty acid. (II) sterol. (III) lipid class, and (IV) oleic acid factors.     

Rapid electrochemical screening of antioxidant capacity (RESAC) of selected tea samples

Antioxidants found in the daily diets behave as chemopreventive agents to inactivate potentially harmful reactive oxygen species present in our organisms. Consequently, it will be quite important to have easy-to-use diagnostic tools to dose antioxidant food ingredients.     

In vitro antioxidant capacity of honeybee-collected pollen of selected floral origin harvested from Romania

Total phenolic phytochemical concentration was measured in 12 honeybee-collected pollens of selected floral species as well as their antioxidant capacity. The content of total polyphenols was measured spectrophotometrically using the Folin–Ciocalteu reagent with gallic acid as standard. The antioxidant properties were evaluated by 2,2-diphenyl-picrylhydrazyl radical scavenging capacity (DPPH) assay, Trolox equivalent antioxidant Capacity procedure and Ferric ion reducing antioxidant power assay. A great variability regarding the correspondence between the antioxidant activity and the content of total polyphenols of honeybee-collected pollens with different botanical origin was found. Antioxidant activities were different for each floral species and were not clearly associated to their total phenolic content.     

萌发对芸豆酚类物质及抗氧化活性的影响

研究了萌发过程对黑芸豆、奶花芸豆、紫花芸豆中多酚、黄酮含量及抗氧活性的影响,并对多酚、黄酮含量及抗氧化能力做了相关性分析。结果表明:三种芸豆萌发（0⁶ d）后多酚、黄酮含量及抗氧化活性较未萌发的均显著降低（p<0.05）。且浸泡损失的多酚、黄酮高于萌发期间;黑芸豆萌发6 d后多酚、黄酮含量可能由于内切酶的作用开始增加。萌发期间,三种芸豆的DPPH·清除能力（DPPH）、ABTS+·清除能力（ABTS）、铁离子还原抗氧化能力（FRAP）、氧化自由基吸收能力（ORAC）均有降低趋势。多酚、黄酮含量与抗氧化能力极显著相关（p<0.01）,且多酚与ABTS值的相关性最高（r=0.955）。此外,黑芸豆的抗氧化能力萌发4 d后开始增加,萌发6 d时黑芸豆和奶花芸豆的ORAC值高于0 d。合适的萌发条件能更好的保留芸豆的生物活性物质。      

Effect of processing on ochratoxin A content in dried beans

Dried pink beans naturally contaminated with ochratoxin A (OTA) and dried carioca beans artificially contaminated with OTA by inoculation with Aspergillus ochraceus (ATCC 22947) were tested for ochratoxin A levels as follows: dried beans were washed with water for 2, 60 or 120 min, soaked in water for 60, 120 min or 10 h, and cooked for 60 or 120 min. At each step, test water and beans were separated. Test water, raw beans and cooked beans were analyzed for OTA. The amount of OTA partitioned into water and in residual beans was determined by methanol–sodium bicarbonate extraction, buffer dilution, immunoaffinity column cleanup, liquid chromatographic separation and fluorescence detection. The results demonstrated that the distribution of OTA in processing water and beans depends on the method of preparation. All treatments (washing, soaking and cooking) when applied individually reduced the amounts of OTA retained in bean flour and whole beans. Higher amounts of OTA remained in whole beans than in bean flour after removing the processing water. The combination of the three treatments eliminated about 50% of the toxin from whole beans. This study provides evidence that discarding the washing, soaking and cooking water leads to a significant reduction in OTA contamination in dried beans.     

Antioxidant and Free Radical Scavenging Activities of Indian Acacias: Acacia Leucophloea (Roxb.) Willd., Acacia Ferruginea Dc., Acacia Dealbata Link. and Acacia Pennata (L.) Willd

The acetone and methanol extracts of barks of A. leucophloea, A. ferruginea, A. dealbata, and A. pennata were evaluated for their total phenolics and flavonoid contents and antioxidative activities. Acetone extracts of barks exhibited higher contents of total phenolics and flavonoids. Further, the acetone extracts showed higher activity in DPPH^?, ABTS^?+, and OH^?; FRAP; metal chelation; phosphomolybdenum reduction; and peroxidation inhibition. In conclusion, the results implied that the barks could be considered as health supplements and nutraceuticals/functional foods.