Development and assessment of GC/MS and HPAEC/PAD methodologies for the quantification of α-galacto-oligosaccharides (GOS) in dry beans (Phaseolus vulgaris).

The quantification of α-Galacto-oligosaccharides (GOS) in beans has been increasingly approached through different methodologies. However, reported GOS contents revealed up to 8-times disparity, which cannot be only attributed to the bean cultivar and underlines the need of using validated analytical methodologies. This study aimed to optimize and validate the extraction of the most abundant GOS found in beans, namely raffinose, stachyose and verbascose, and comparatively assess their determination by High-Performance Anion Exchange Chromatography/Pulsed Amperometric Detector (HPAEC/PAD) and Gas Chromatography/Mass Spectrometry (GC/MS). Hot sonication followed by shaking with 70% ethanol resulted in excellent GOS extraction efficiencies (92.54-107.94%). GC/MS determination was more reliable than HPAEC/PAD, with limits of quantification of 4.48-224.31 mg/kg and intra/inter-day repeatabilities <10%. The analysis of six bean varieties proved the feasibility of the GC/MS methodology, displaying total GOS contents from 1453.07 ±â€¯169.31 to 2814.34 ±â€¯95.28 mg/100 g. Stachyose was significantly (p < 0.05) the main GOS in all samples.

Residue dynamics and risk assessment of Luna Experience® (fluopyram + tebuconazole) and chlorpyrifos on French beans (Phaseolus vulgaris L.).

The persistence of chlorpyrifos, fluopyram, and tebuconazole was estimated in green pods, matured seeds, and soil of French beans using dispersive QuEChERS. Three foliar applications each of chlorpyrifos and a combination fungicide fluopyram + tebuconazole (Luna experience, 400 SC) were applied at 600 and 125 + 125 as a standard dose and 1200 and 250 + 250 g a.i. ha-1 as a double dose, respectively, were applied at an interval of 10 days and treated pods were picked up at regular intervals. Dried mature seeds and soil were also monitored at harvest. The initial deposits of chlorpyrifos on bean pods were 3.083 and 6.017 mg kg-1 with a half-life of 1.86 and 2.29 days, at respective doses. Foliar application of a combi product Luna experience yielded 3.396 and 5.772 mg kg-1 residues of fluopyram and 3.613 and 5.887 mg kg-1 of tebuconazole in green pods at standard and double dose with almost same half-lives of 3.4 and 3.8-3.9 days. Residues declined below the limit of quantitation (LOQ) of 0.05 mg kg-1 in green beans after 15 and 25 days after the application of double dose of chlorpyrifos and Luna experience, respectively. However, the residues in dry bean seeds and soil reached below the LOQ of 0.05 mg kg-1 at the time of harvest. A pre-harvest interval of 5, 10, and 7 days has been proposed for chlorpyrifos, fluopyram, and tebuconazole, respectively, in beans. HQ < 1 and TMDI < MPI in all test chemicals. Hence, it was concluded that a waiting period of 5 days for chlorpyrifos and 7-10 days in Luna experience will be safer to consumers. This data generated will be useful for regulatory agency for fixing MRLs.

Toxicity Assessment of Common Beans (Phaseolus vulgaris L.) Widely Consumed by Tunisian Population.

This research aimed at assessing the content and the functional properties of phytohemagglutinin (PHA) in different varieties of beans widely consumed in Tunisia through soaking, cooking, autoclaving, germination, and their combinations. This study was carried out on three varieties of white beans grown in different localities of Tunisia, namely Twila, Coco, and Beldia, as well as on imported and local canned beans. All bean samples underwent biochemical and immunological evaluation by employing several techniques such as indirect competitive enzyme-linked immunosorbent assay (ELISA), hemagglutinating assay, Ouchterlony double immunodiffusion, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Biochemical and immunological analyses indicated that raw dry beans contained a considerable amount of proteins and PHAs. ELISA demonstrated that soaking, either in plain water or in alkaline solution, caused an increase in the concentration of PHA. A slight increase of PHA was produced equally by germination during 4 days in all bean varieties. Cooking or autoclaving of presoaked beans resulted in a complete disappearance of PHA. ELISA test also proved that both imported and local canned beans contained fingerprints of PHA. Hemagglutination assays showed that not only cooked and autoclaved presoaked beans lacked the ability to agglutinate red blood cells but also autoclaved unsoaked beans did. In agar gel immunodiffusion using rabbit anti-PHA serum, raw, soaked, cooked unsoaked, and sprouted beans gave precipitin arc reactions, indicating that PHA existed in immunoreactive form in the tested seeds. SDS-PAGE electrophoretograms showed protein isolates of Twila and Beldia beans to have different profiles through soaking, cooking, and autoclaving processes. This work revealed that the combination of soaking and cooking/autoclaving was the best way in reducing PHA content and its activity in all bean varieties when compared with germination.

Leucoagglutinating phytohemagglutinin: purification, characterization, proteolytic digestion and assessment for allergenicity potential in BALB/c mice.

Red kidney bean (Phaseolus vulgaris) is consumed worldwide as a vegetarian protein source. But, at the same time the allergenicity potential of red kidney bean is a matter of concern. This study is aimed towards purification, characterization, thermal stability, proteolytic digestion and allergenicity assessment of one of the clinically relevant allergens of red kidney bean. The purification of red kidney bean allergic protein was carried out with the help of column chromatography, IgE immunoblotting and reverse phase high-pressure liquid chromatography (RP-HPLC). The purified protein was characterized by peptide mass finger printing (PMF) and studied for its thermal stability, and proteolytic resistance using simulated gastric fluid (SGF) assay. The allergenicity potential of the purified protein was studied in BALB/c mice. The purified protein was identified as leucoagglutinating phytohemagglutinin (PHA-L) with molecular weight 29.5 kDa. The PHA-L showed resistance to heat as well as proteolytic enzyme. Higher levels of total IgE, specific IgE, and histamine were observed in PHA-L treated BALB/c mice when compared to control. Overall, PHA-L possesses characteristics of allergens and may play a potential role in the red kidney bean induced allergy.

Microwave and micronization treatments affect dehulling characteristics and bioactive contents of dry beans (Phaseolus vulgaris L.).

BACKGROUND: Heat pretreatment is considered the first step in grain milling. This study therefore evaluated microwave and micronization heat treatments in improving the dehulling characteristics, phenolic composition and antioxidant and α-amylase activities of bean cultivars from three market classes. RESULTS: Heat treatments improved dehulling characteristics (hull yield, rate coefficient and reduced abrasive hardness index) depending on bean cultivar, whereas treatment effects increased with dehulling time. Micronization increased minor phenolic components (tartaric esters, flavonols and anthocyanins) of all beans but had variable effects on total phenolic content depending on market class. Microwave treatment increased α-amylase inhibitor concentration, activity and potency, which were strongly correlated (r² = 0.71, P < 0.0001) with the flavonol content of beans. Heat treatment had variable effects on the phenolic composition of bean hulls obtained by abrasive dehulling without significantly altering the antioxidant activity of black and pinto bean hulls. Principal component analysis on 22 constituents analyzed in this study demonstrated the differences in dehulling characteristics and phenolic components of beans and hulls as major factors in segregating the beneficial heat treatment effects. CONCLUSION: Heat treatment may be useful in developing novel dietary fibers from beans with variable composition and bioactivity with a considerable range of applications as functional food ingredients.

Direct defense or ecological costs: responses of herbivorous beetles to volatiles released by wild Lima bean (Phaseolus lunatus).

In response to feeding damage, Lima bean releases herbivore-induced plant volatiles (HIPV), which are generally assumed to attract carnivorous arthropods as an indirect defense. While many studies have focused on such tritrophic interactions, few have investigated effects of HIPV on herbivores. I used natural herbivores of wild Lima bean and studied their responses to jasmonic acid-induced plants in an olfactometer and in feeding trials. Both Cerotoma ruficornis and Gynandrobrotica guerreroensis (Chrysomelidae) significantly preferred control plants to induced ones in the olfactometer, and they avoided feeding on induced plants. In contrast, Curculionidae significantly preferred HIPV of the induced plant to those of the control in one plant pair and did not choose in the case of a second pair. In feeding trials, no choice occurred in the first plant pair, while control leaves were preferred in the second. Release of HIPV deterred Chrysomelid herbivores and, thus, acted as a direct defense. This may be an important addition to indirect defensive effects. Whether or not HIPV released by induced plants attracted herbivorous Curculionidae, thus incurring ecological costs, varied among plants. Such differences could be related to various HIPV blends released by individual plants.

Data from amplified fragment length polymorphism (AFLP) markers show indication of size homoplasy and of a relationship between degree of homoplasy and fragment size.

We investigate the distribution of sizes of fragments obtained from the amplified fragment length polymorphism (AFLP) marker technique. We find that empirical distributions obtained in two plant species, Phaseolus lunatus and Lolium perenne, are consistent with the expected distributions obtained from analytical theory and from numerical simulations. Our results indicate that the size distribution is strongly asymmetrical, with a much higher proportion of small than large fragments, that it is not influenced by the number of selective nucleotides nor by genome size but that it may vary with genome-wide GC-content, with a higher proportion of small fragments in cases of lower GC-content when considering the standard AFLP protocol with the enzyme MseI. Results from population samples of the two plant species show that there is a negative relationship between AFLP fragment size and fragment population frequency. Monte Carlo simulations reveal that size homoplasy, arising from pulling together nonhomologous fragments of the same size, generates patterns similar to those observed in P. lunatus and L. perenne because of the asymmetry of the size distribution. We discuss the implications of these results in the context of estimating genetic diversity with AFLP markers.