Características físicas y antioxidantes de semillas y productos de mostaza negra (Brassica nigra) y amarilla (Brassica alba) / Physical and antioxidant characteristics of black (Brassica nigra) and yellow mustard (Brassica alba) seeds and their products

En este trabajo se evaluaron la composición, algunas características físicas (densidad, índice de refracción y color), capacidad antioxidante (DPPH) y perfil de ácidos grasos de semillas de mostaza negra (Brassica nigra) y amarilla (Brassica alba), sus aceites y residuos de la extracción del aceite. La densidad de los aceites de mostaza negra y amarilla fue de 0,912 ± 0,01 y 0,916 ± 0,01 g/mL, respectivamente; y el índice de refracción fue de 1,4611 ± 0,01 y 1,4617 ± 0,01, respectivamente, no mostrando diferencias significativas (p>0,05) entre las dos mostazas. Los parámetros de color del aceite de semilla de mostaza negra y amarilla tienden hacia los tonos amarillos-verdosos y tonos amarillos-rojizos, respectivamente; respecto a la actividad antioxidante, se observó una variación desde 25 mg equivalentes de Trolox/100 g en el aceite de semilla de mostaza amarilla hasta 1,366 mg equivalentes de Trolox/100 g en la pasta residual de mostaza negra. El perfil de ácidos grasos de la semillas de mostaza negra muestran que el ácido graso predominante es el oleico (22,96%), seguido por linoleico (6,63%) y linolénico (3,22%), mientras que para la semilla de mostaza amarilla es el erúcico (6,87%), seguido por oleico (5,08%) y linoléico (1,87%).

The composition, some physical properties (density, refraction index, and color), antioxidant capacity (DPPH), and fatty acid profile of seeds of black (Brassica nigra) or yellow mustard (Brassica alba) were evaluated, as well as for their oils and residues from oil extraction. Density of the black and yellow mustard oils were 0.912 ± 0.01 and 0.916 ± 0.01 g/mL, respectively; their refraction indexes were 1.4611 ± 0.01 and 1.4617 ± 0.01, respectively; being not significantly different (p>0.05) between two mustards. Color parameters of the black and yellow mustard oils presented greenish-yellow tones and reddish-yellow tones, respectively; regarding antioxidant activities, these ranged from 25 mg equivalents of Trolox/100 g in the yellow mustard oil to 1,366 mg equivalents of Trolox/100 g in the residues from oil extraction of black seed mustard. The fatty acid profile of the black mustard seed revealed that its predominant fatty acid is oleic (22.96%), followed by linoleic (6.63%) and linolenic (3.22%), whereas for yellow mustard seed the major fatty acid is erucic (6.87%), followed by oleic (5.08%) and linoleic (1.87%) acids.

Screening and Production of Biodegradable Polyester Poly(3-hydroxybutyrate) by Bacteria Endophytic to Brassica nigra L.

Aims: Poly(3-hydroxybutyrate) [P(3HB)], the microbially produced biodegradable thermoplastics has find wide range of applications in recent years. Development of low cost production strategies utilizing novel organisms is a crucial challenge. Present study is aimed to isolate and screen bacterial endophytes of Brassica nigra L. for the production of P(3HB). Place and Duration of Study: The experiments were performed in the Microbiology Laboratory, Department of Botany, University of Calcutta, Kolkata during 2012-2014. Methodology: Culturable bacterial endophytes were isolated from surface sterilized healthy tissues of B. nigra L. and screened for P(3HB) production in mineral salts medium. The chloroform extracted dried polymer was treated with H2SO4 and quantified spectrophotometrically at 235 nm. Results: About 78% of the bacterial endophytes recovered from surface sterilized B. nigra L. tissues showed different degrees of P(3HB) accumulation. Isolates (9) showing P(3HB) accumulation exceeding 10% of the cell dry weight (CDW) were characterized and tentatively identified as members of Bacillus, Pseudomonas, Xanthomonas, Alcaligenes and Acetobacter. The most potent isolate, BNL 06 identified as Bacillus pumilus BNL 06 (GenBank Accession No. KP202723), accumulated P(3HB) accounting 18% of CDW with an yield of 0.55 g/l. Finally the nature of the polymer was further confirmed by FTIR analysis. Conclusion: Exploration of the endophytic bacterial diversity of B. nigra L. have clearly revealed the potential of Bacillus pumilus BNL 06 for P(3HB) production as an alternative source of thermoplastics.

Brassica nigra and cuminum cyminum: Inhibitors of food borne pathogens.

Dried seeds of spices namely Brassica nigra (mustard) and Cuminum cyminum (cumin) were screened independently, in culture media, in their different forms (aqueous extracts, essential oils and powders) against some bacterial strains of spoilage and health significance. Test microorganisms included one gram+ve bacterial strain i.e. Bacillus cereus (MTCC 430) and three gram-ve bacterial strains viz. Enterococcus faecalis (MTCC 439), Psuedomonas aeruginosa (MTCC 1688) and Shigella sonnei (MTCC 2957). Spice agar method was opted for screening antibacterial activities of powdered forms of aforementioned spices at their different concentration levels (0.0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0 (% (w/v)). B.nigra more effectively inhibited bacterial strains in culture media. Minimum inhibitory concentrations (MIC) of powdered form of B.nigra were also determined. It was the concentration of spice which arrested the growth of bacterial strain upto 80% level of the total incubation period of 30 days. Agar-well assay was followed for antibacterial screening of aqueous extracts and essential oils of test spices. Aqueous extracts of reference spice samples did not exhibit growth inhibitory zones towards any test bacterial strains. On the other hand, essential oils of B.nigra and C.cyminum showed distinct growth inhibitory zones against all the bacterial strains under observation. Results obtained from agar well assay revealed that essential oil of B.nigra was more potent in inhibiting bacterial strains followed by C. cyminum . It was also noticed that B. cereus (gram+ve) was inhibited at lower concentrations of test substances as compared to all the other three gram-ve bacterial strains under investigation.