Volatile profiles of Murcott and Ponkan mandarins obtained by stir bar sorptive extraction technique and their contributions to the fruit aroma.

Citrus species have undergone immense diversification ever since their ancestral origin. Ponkan and Murcott are two mandarin varieties widely consumed in Brazil and their aroma producing active compounds have not yet been extensively investigated. The present study analyzed the volatile constituents of the Ponkan and Murcott varieties employing the stir bar sorptive extraction (SBSE) technique and gas chromatography-mass spectrometry (GC-MS) analysis for the first time. Extraction was performed using the two phases of Twister bar, polydimethyl siloxane (PDMS), and ethylene glycol (EG) silicone in immersion and headspace modes. Among the detected 62 compounds comprising alcohols, aldehydes, esters, terpenes, and others identified, 55 and 37 compounds in the Ponkan and Murcott variety were determined, respectively, from both immersion and headspace modes using the two phases of Twister bar. From the odor active values, the Ponkan was characterized with the domination of compounds such as hexanal, decanal, nonanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, linalool, and geraniol. Similarly, the Murcott variety was characterized with predominant compounds, namely, nonanal, octanal, hexanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, and linalool. The profile of volatile compounds was found to be unique in both the varieties studied, and SBSE technique with GC-MS analysis favored the characterization of their respective profile due to the high amount of phase in the Twister bars, when compared to similar techniques, like solid phase microextraction. The PDMS Twister bar showed better capacity of adsorption of volatile compounds, since it is a relatively low-polarity polymer, which discriminates less analytes with different structures and polarities sampled from complex matrices, such as fruits juice.

Chemical characterization and antimicrobial activity of essential oils from Croton grewioides Baill. accessions on the phytopathogen Xanthomonas campestris pv. campestris.

Croton grewioides Baill. is an aromatic species with proven bioactive properties. Considering the potential of the species, the aim of this study was to chemically characterize and evaluate the in vitro antibacterial activity of the essential oils of C. grewioides on Xanthomonas campestris pv. campestris. The essential oils of the accessions of C. grewioides were extracted by the hydrodistillation method and analyzed by gas chromatography - mass spectrometry. For determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the essential oils and of the compound eugenol, the microdilution method was used at concentrations that ranged from 125 to 4000 µg.mL-1. Streptomycin sulfate was used as a positive control (12.5 to 100 µg.mL-1). Growth kinetics and the membrane permeability trial were evaluated for the concentrations 2×, 1×, 1/2×, 1/4×, and 1/8× MIC of the essential oil CGR-108. The major compounds identified in the essential oils were eugenol, methyl eugenol, and methyl chavicol. The essential oil of the accession CGR-108 had a lower MIC (> 500 and < 1000 µg.mL-1) and MBC equal to <2000 µg.mL-1. For eugenol, MIC was obtained with contractions >250 and < 500 µg.mL-1 and MBC with >500 µg.mL-1 and < 1000 µg.mL-1. A loss of cell viability of the bacteria was observed after 30 min of exposure to the essential oil of the accession CGR-108 at the concentrations of 2× and 1× MIC, which was proven by the fluorescence intensity with propidium iodide. The essential oils of Croton grewioides Baill. and the compound eugenol show antibacterial potential on Xanthomonas campestris pv. campestris.

Effect of spray drying on bioactive and volatile compounds in soursop (Annona muricata) fruit pulp.

Soursop is seasonal and highly perishable fruit, which limits its commercialization. Thus it is necessary to conserve its pulp so that it is available throughout the year. One of the most common forms of fruit preservation is by dehydration. This work had an objective to dehydrate soursop pulp by spray drying at optimum conditions and to analyze the retention of bioactive and volatile compounds in soursop powder, besides analyzing its antioxidant capacity. The total phenolics, carotenoids and flavonoids contents were determined, while volatile compounds were analyzed by Stir Bar Sorptive Extraction (SBSE) coupled with GC-MS system. The total content of the phenolic compounds and flavonoids in the fresh pulp were 160.28 mg of GAE/100 g and 87.17 mg of quercetin/100 g, respectively while for rehydrated dried powder their values were 158.95 mg of GAE/100 g and 85.17 mg of quercetin/100 g, respectively. The total phenolic compounds, flavonoids and antioxidant capacity did not show any significant difference (p < .05) between the fresh fruit pulp and dehydrated powder. A total of 85 volatile compounds were identified, of which 33 were esters, representing the major class of organic compounds, 15 were terpenes, 10 aldehydes, 7 acids, 5 alcohols, 5 lactones, 3 ketones, and 6 other compounds. Of the total 85 compounds, identified in soursop pulp, 58 compounds were identified in the rehydrated dried powder. The principal compounds for both samples were methyl (E)-2-hexenoate, methyl hexanoate and methyl (E)-2-butanoate, which contribute to soursop aroma according to their Odor Active Values (OAV). Considering that there was no significant difference (p < .05) between fresh pulp and the rehydrated dried powder in concentrations of bioactive compounds and even with the reduction in the concentration of the main volatile compounds while the OAVs of these compounds were relatively high, it is concluded that spray dried powder of soursop pulp retains its nutritional and aroma quality, besides maintaining the antioxidant capacity.

Influência da temperatura de entrada de secagem e concentração de maltodextrina sobre as propriedades físico-química de polpa de acerola em pó / Influence of drying entry temperature and maltodextrin concentration on the physical-chemical properties of powdered powder

O objetivo do presente trabalho foi avaliar a influência da concentração da maltodextrina e da temperatura de entrada de secagem sob as características físico-químicas de polpa de acerola em pó. As acerolas maduras foram selecionadas, lavadas, sanitizadas, enxaguadas e despolpada. As polpas foram divididas em quatro tratamentos, utilizando-se duas concentrações de maltodextrina (14 e 26%) que foram atomizadas em spray dryer em duas temperaturas (128 e 152°C). A polpa em pó e in natura foram analisadas quanto a umidade, SST, ATT, pH e carotenoides. De acordo com os resultados obtidos foi possível verificar que os teores de umidade foram influenciados pela temperatura e concentração de maltodextrina. A acidez da polpa em pó diminui com o aumento da do agente carreador. O teor de carotenoides não apresentou diferença significativa entre os tratamentos estudados. Para o processo de atomização da acerola por spray dryer indica-se o uso de maltodextrina a 26% independente da temperatura.

Influência da torrefação no rendimento de óleo de sementes de melão obtido por extração assistida por ultrassom / Influence of roasting on the yield of melon seeds obtained by ultrasound-assisted extraction

Os resíduos do processamento de frutas, como o melão, têm se tornado um problema para as agroindústrias, pois são gerados em grandes quantidades e podem provocar danos ao meio ambiente quando descartados inadequadamente. Diante disto, o objetivo deste trabalho foi estudar a influência da torrefação no rendimento de óleo das sementes de melão obtido por extração assistida por ultrassom. Para tanto, as sementes foram caracterizadas físico-quimicamente, e o rendimento de óleo foi estudado em relação à temperatura e o tempo de torrefação, utilizando um fatorial 22 com blocos casualizados. Os resultados mostraram que a temperatura e o tempo de torrefação influenciaram no rendimento do óleo de sementes de melão, sendo que os maiores rendimentos de óleo foram obtidos nas condições de 89 ºC por 53 minutos e de 131 ºC por 17 minutos.