Gulab Newandram Jham

Composition and Antifungal Activity of the Essential Oil of the Brazilian Chenopodium ambrosioides L.

The antifungal activity of essential oil (EO) from the Brazilian epazote (Chenopodium ambrosioides L.) was evaluated by the poison food assay at concentrations of 0.3%, 0.1%, and 0.05% with eight postharvest deteriorating fungi (Aspergillus flavus, Aspergillus glaucus, Aspergillus niger, Aspergillus ochraceous, Colletotrichum gloesporioides, Colletotrichum musae, Fusarium oxysporum, and Fusarium semitectum). EO components were tentatively identified by Kováts retention indices (RIs) using gas chromatography and gas chromatography combined with mass spectrometry (GC-MS). Growth of all fungi was completely inhibited at 0.3% concentration, and by 90% to 100% at 0.1% concentration. The following 13 tentatively identified compounds (relative percent) accounted for 90.4% of the total volatile oil: α-terpinene (0.9), p-cymene (2.0), benzyl alcohol (0.3), p-cresol (0.3), p-mentha-1,3,8-triene (0.2), p-cimen-8-ol (0.6), α-terpineol (0.5), (Z)-ascaridole (61.4), piperitone (0.9), carvacrol (3.9), (E)-ascaridole (18.6), (E)-piperitol acetate (0.5), and (Z)-carvyl acetate (0.3). Autobiographic thin layer chromatography of the EO to separate the principal fungitoxic fraction yielded only one fraction that completely inhibited the growth of all test fungi at a concentration of 0.1%. This fraction was characterized by RIs and GC-MS presenting a composition (%) of p-cymene (25.4), (Z)-ascaridole (44.4), and (E)-ascaridole (30.2). The results suggest ascaridoles were the principal fungitoxic components of the EO.

Changes in guava (Psidium guajava L. var. Paluma) nectar volatile compounds concentration due to thermal processing and storage

Guava nectars were formulated for approximately 10, 12, or 14 oBrix, with 40% guava pulp. Sodium benzoate, 500 mg.kg-1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 oC/42 seconds) in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 oC) or refrigerated (5 ± 2 oC) under fluorescent light exposure and analyzed on the day after processing (time zero) and also 40, 80, and 120 days of storage. Eight compounds were identified and quantified by Gas Chromatography (GC) -Mass Spectrometry (MS): hexanal, (E)-hex-2-enal, 1-hexenol, (Z)-hex-3-enol, (Z)-hex-3-enyl acetate, phenyl-3-propyl acetate, cinnamyl acetate, and acetic acid. There was no significant effect of thermal treatment on the volatile compound concentrations, except for a significant decrease (p = 0.0001) in hexanal and (Z)-hex-3-enyl acetate (p = 0.0029). As for the storage time, there was a much greater decrease in the esters contents, such as (Z)-hex-3-enyl and phenyl-3-propyl acetates. Cinnamyl acetate had the greatest decrease over storage time. Refrigeration was better than room temperature for guava nectar volatile compounds stability over storage time, mainly for esters compounds, which are important for the product aroma and flavor

Efeito do dessecante paraquat na qualidade da fração lipídica da soja

Para se determinar a qualidade da fracao lipidica de graos de soja submetidas a aplicacao do dessecante bipiridilio (paraquat), foram estudados a composicao quimica e os indices quimicos de 3 (tres) amostras de oleo bruto e 1 (uma) amostra de oleo refinado. Os oleos analisados no presente trabalho foram provenientes da regiao de Itumbiara - GO, extraidos de graos de soja submetidos ou nao a aplicacao de paraquat. Utilizaram-se tambem amostras de oleo bruto extraidas por solvente, em laboratorio, provenientes de graos de soja sujeitos ou nao a aplicacao de dessecante. Nenhum residuo do dessecante foi detectado, sensibilidade de 0,01 µg/g. O perfil de acidos graxos, medido pelos teores dos acidos palmitico, estearico, oleico, linoleico e linolenico, encontrara-se dentro das faixas convencionais do oleo de soja de 9 a 4,5, 2,5 a 5,0, 18 a 34, 45 a 60 e 3,5 a 8,0%, respectivamente. No entanto, os indices de saponificacao (de 161 a 171) ficaram abaixo dos valores estabelecidos pela legislacao brasileira (189 a 198). Ja os acidos graxos livres, materia insaponificavel dos oleos brutos, e o indice de iodo do oleo refinado estao dentro desses padroes, maximos de 2,0%, 1,5% e 120 a 143, respectivamente. Os teores de ferro e de cadmio de 1,45 e 0,39 µg/g, respectivamente, de oleo refinado, atendem a legislacao. Nao se detectou chumbo, a sensibilidade de 0,01 µg/g. Esses metais foram analisados por espectrofotometria de absorcao atomica.