ABSTRACT
Abstract The effect of irradiation through UV-C on the content of phenolic compounds, antioxidant activity, color, and texture profile was evaluated in Bordô variety grapes. Grapes were subjected to stress by irradiation at time of 0.5, 1.0, 4.0, 10 and 30 min that correspond at doses of 0.1, 0.3, 1.0, 2.4, and 7.2 kJ m-2, respectively. The total phenolic and anthocyanins content, antioxidant activity, color and texture of the grapes were evaluated after storage at 22 ºC for 24 and 48 h. In general, samples irradiated did not show an increase in total phenolic content, anthocyanin compounds and antioxidant activity. Hue and Chroma values indicated that the color of grapes did not change when irradiated. Texture profile analysis suggested that UV-C treatment delayed grapes softening.
ABSTRACT
ABSTRACT This study aimed to evaluate the influence of the drying air temperature (140 and 160°C) and the concentration of encapsulating agents gum Arabic and polydextrose (10 and 15%) on the physicochemical characteristics of the red cabbage extract obtained through extraction in acidulated water and drying using a spray dryer. The anthocyanin retention, antioxidant activity, water activity, solubility, color and microstructure of the final product were analyzed. Results showed that increase in the temperature did not cause significant changes in the anthocyanin quantity and antioxidant activity. The microscopic analysis revealed that for both the encapsulating agents, the absence of fissures and porosity in the particle surfaces produced powder with high solubility in water. The principal component analyses showed a strong correlation between the anthocyanin content and the antioxidant activity (r = 0.82) and luminosity (r = 0.81).
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The present work aimed to evaluate glycerol, maltodextrin, polydextrose and sorbitol for the osmotic dehydration of yacon for diabetics, keeping its properties as prebiotic. Osmotic dehydration was carried out using a yacon to 33% concentrated syrup weight ratio of 1:12, with magnetic stirring at 23ºC and atmospheric pressure. The best results were achieved for glycerol and sorbitol with 80 ± 4% and 81± 1% of water removal and increase of 3.73 ± 0.11 and 4.30 ± 0.16 times in total soluble solids respectively. Maltodextrin did not promote dehydration.
ABSTRACT
Fructooligosaccharides (FOS) are food ingredients applied due to combination of prebiotic benefits and interesting technological properties, being used as a sugar substitute. The knowledge of their physicochemical characteristics is important for predicting the stability of the food products where they are added. For this reason, a saccharides powder extracted from yacon (Smallanthus sonchifolius) roots by membrane technology and freeze-dried was investigated. Color, water activity (aw), microstructure by Scanning Electron Microscopy coupled to Energy- dispersive X-ray Spectroscopy (SEM-EDS) and crystallinity by X-ray diffraction were evaluated. The obtained product, containing 19.75% FOS, 36.66% glucose and 43.59% fructose (w/w) was a whitish granulated powder, with aw of 0.284 and CIELAB color coordinates L*, a* and b* of 76.25±1.19, -1.03±0.09 and 1.02±0.03, respectively. It was highly hygroscopic and with agglomeration tendency, confirmed by the formation of bridges between particles on the SEM images. No peaks were identified at X-ray diffractograms, indicating its amorphous characteristics, but sample high hygrospicity and formation of a rigid mass might have hampered a trustable X-ray analysis.
ABSTRACT
The effect of modified atmosphere packaging on the mortality of Sitophilus spp. in organic maize grain was studied. Maize grains were packed with five different atmospheres consisting of 20 percent O2, or 20, 40, 60, 80 percent CO2 with remaining N2. The packages were stored for 30 days at 26°C. CO2 and O2 concentrations were monitored inside the packages during the storage. The moisture content, titratable acidity and pH were analysed on the first and thirtieth day. At 5, 15 and 30 days of storage no significant differences were observed in the percentages of dead insects when CO2 was used. The results of progeny indicated that from the fifth day the number of emerging insects was low at 20, 60 and 80 percent CO2. Complete inhibition of the insects was achieved with 30 days of exposure in CO2 atmospheres.
O efeito da embalagem em atmosferas modificadas sobre os insetos Sitophilus spp. nos grãos de milho orgânico foi estudado. Os grãos de milho foram empacotados em cinco atmosferas iniciais diferentes de 20 por cento de O2, ou 20, 40, 60, 80 por cento de CO2 com balanço de N2. As embalagens foram armazenadas por 30 dias a 26ºC. As concentrações de CO2 e O2 foram monitoradas dentro das embalagens durante o armazenamento. As análises de teor de umidade, acidez e pH foram também realizados no primeiro e trigésimo dia. Os resultados mostraram que no quinto, décimo quinto e trigésimo dia de estocagem não foram encontrados diferenças significativas nas porcentagens de insetos mortos quando CO2 foi usado. Os resultados relativos à progênie indicaram que no quinto dia o número de insetos emergentes foi menor a 20, 60 e 80 por cento CO2. A completa inibição dos insetos foi atingida com 30 dias de exposição em atmosferas de CO2.