Caciano Pelayo Zapata Noreña

Degradation kinetics of anthocyanin in blueberry juice during thermal treatment.

The kinetics of anthocyanin degradation in blueberry juice during thermal treatment at 40, 50, 60, 70, and 80 degrees C were investigated in the present study. Anthocyanin degradation was analyzed up to the level of 50% retention using a pH differential method. The degradation of anthocyanin at each temperature level followed a first-order kinetic model, and the values of half-life time (t(1/2)) at temperatures of 40, 50, 60, 70, and 80 degrees C were found to be 180.5, 42.3, 25.3, 8.6, and 5.1 h, respectively. The activation energy value of the degradation of the 8.9 degrees Brix blueberry juice during heating was 80.4 kJ.mol(-1). The thermodynamic functions of activation (DeltaG, DeltaH, and DeltaS) have been determined as central to understanding blueberry degradation.

Study on the stability of β-carotene microencapsulated with pinhão (Araucaria angustifolia seeds) starch.

Native and hydrolyzed pinhão starches were used as coating materials for β-carotene microencapsulation by freeze-drying. The purpose of the present study was to evaluate the stability of β-carotene encapsulated under three different conditions: in the presence of ultraviolet light at 25±2 °C, in the dark at 25±2 °C and in the dark at 10.0±0.2 °C. The color of the samples was also analyzed. Microcapsules prepared with native starch showed the lowest stability during storage. In contrast, microcapsules encapsulated with 12 dextrose equivalent (DE) hydrolyzed starch exhibited the highest stability. First-order kinetic and Weibull models were applied to describe the degradation of β-carotene over time. The R(2) values of the Weibull model were greater than those of the first-order kinetic model. Moreover, multivariate analyses (principal component and cluster analyses) were also conducted.

Effect of the alkaline treatment on the ultrastructure of C-type starch granules.

The effect of alkaline treatment on the ultrastructure of C-type starch granules was investigated during the alkaline extraction of Araucaria angustifolia (pinhao) starch. The efficiency in protein removal was evaluated using intrinsic fluorescence and Kjeldahls method. In parallel, morphological changes of starch granules were observed using scanning electron microscopy and atomic force microscopy. The starch crystallinity was monitored by wide-angle X-ray scattering and the lamellar structure was studied by small-angle X-ray scattering (SAXS). The paracrystalline model was employed to interpret the SAXS curves. It was found that the granular organization was significantly altered when alkaline solutions were used during the extraction. A partial degradation of B-type allomorph of starch and a significant compression of semicrystalline growth rings were observed.

Microencapsulation of grape (Vitis labrusca var. Bordo) skin phenolic extract using gum Arabic, polydextrose, and partially hydrolyzed guar gum as encapsulating agents

Bordo grape skin extract was microencapsulated by spray-drying and freeze-drying, using gum arabic (GA), partially hydrolyzed guar gum (PHGG), and polydextrose (PD) as encapsulating agents. Total phenolics and total monomeric anthocyanin, antioxidant activity, color, moisture, water activity (aw), solubility, hygroscopicity, glass transition temperature (Tg), particle size, and microstructure of the powders were evaluated. The retention of phenolics and anthocyanins ranged from 81.4% to 95.3%, and 80.8% to 99.6%, respectively, while the retention of antioxidant activity ranged from 45.4% to 83.7%. Treatments subjected to spray-drying had lower moisture, aw, and particle size, and greater solubility, while the freeze-dried samples were less hygroscopic. Tg values ranged from 10.1 to 52.2°C, and the highest values corresponded to the spray-dried microparticles. The spray-dried particles had spherical shape, while the freeze-dried powders showed irregular structures. The spray drying technique and the use of 5% PHGG and 5% PD has proven to be the best treatment.

Antimicrobial activity of chitosan films containing nisin, peptide P34, and natamycin

The antimicrobial effect of edible chitosan films containing nisin, peptide P34, and natamycin was investigated. The activity of chitosan films was tested against Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Clostridium perfringens, Lactobacillus acidophilus, Aspergillus phoenicis, and Penicillium stoloniferum. The addition of nisin and P34 significantly increased the activity against bacteria. Films containing natamycin showed similar inhibition than those with chitosan alone. Chitosan films were effective to control microbial growth in minimally processed pear. Fourier transform infrared spectra of the films were similar, indicating the absence of relevant interaction between the polymer and the antimicrobial agent. The films were also analyzed by scanning electron microscopy to visualize the surface topography. Chitosan films were rough and heterogeneous. The incorporation of antimicrobials agents to edible chitosan films or covering may be a feasible and attractive method for food biopreservation.

Microencapsulation of palm oil by complex coacervation for application in food systems

This study aimed at microencapsulating palm oil, containing high carotenoid content, with chitosan/xanthan and chitosan/pectin, using the complex coacervation method, followed by atomization and lyophilization. The DSC technique was used to confirm the encapsulation. The atomized microparticles had spherical shape and irregular size, and the lyophilized microparticles had irregular shape and size. Lyophilization resulted in lower carotenoids losses, and higher yield and encapsulation efficiency. In addition, the release profile in both water and gastrointestinal fluid was satisfactory. Prior to their application in food, a greater percentage of carotenoids was released in the fluid that simulates gastrointestinal conditions; however, the compounds were degraded after their release. In this case, the chitosan/pectin microparticles showed the best release profile. After processing, the release was lower and the released compounds were not degraded. Thus, the chitosan/xanthan microparticles showed the best potential for practical application, particularly, in yogurt preparation.

The effect of acid hydrolysis on the technological functional properties of pinhão (Araucaria brasiliensis) starch

Technological functional properties of native and acid-thinned pinhao (seeds of Araucaria angustifolia, Brazilian pine) starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 oC, 6 hours) and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days), paste freezing and thawing stability (after six freezing and thawing cycles), swelling power, and solubility. The results of light transmittance (%) of pastes of native and acid-thinned pinhao starches was higher (lower tendency to retrogradation) than that obtained for corn starches after similar storage period. Native pinhao starch (NPS) presented lower syneresis than native corn starch (NCS) when submitted to freeze-thaw cycles. The acid hydrolysis increased the syneresis of the two native varieties under storage at 5 oC and after freezing and thawing cycles. The solubility of NPS was lower than that of native corn starch at 25, 50, and 70 oC. However, for the acid-thinned pinhao starch (APS), this property was significantly higher (p < 0.05) when compared to that of acid-thinned corn starch (ACS). From the results obtained, it can be said that the acid treatment was efficient in producing a potential fat substitute from pinhao starch variety, but this ability must be further investigated.

Inactivation of Trypsin Inhibitor Activity from Brazilian Varieties of Beans (Phaseolus vulgaris L.)

The trypsin inhibitor activity (TIA) of five varieties of beans (Phaseolus vulgaris L.) namely, Carioca, Branco, Vermelho, Preto and Jalo, was investigated. No significant differences of TIA among varieties of raw beans were observed (P > 0.05). Pressure-cooking (121°C and 141 kPa) for 15 min resulted in complete inactivation of TIA. On cooking beans in water bath (90°C, 15 min), the TIA was inactivated between 80% and 95%, while total inactivation was achieved after 40 min suggesting the possibility of two-step inactivation kinetics. Microwave treatment was very effective for inactivation of this antinutritional factor (97% to 100% of inactivation) in the first 15 min of treatment. A 22 factorial design was developed to evaluate the effect of temperature and duration of thermal treatment for loss of TIA. As interdependence between temperature and time was evident, it is envisaged that both are important to process the beans to knock off TIA.

Efficacy of modified atmosphere packaging to control Sitophilus spp. in organic maize grain

O efeito da embalagem em atmosferas modificadas sobre os insetos Sitophilus spp. nos graos de milho orgânico foi estudado. Os graos de milho foram empacotados em cinco atmosferas iniciais diferentes de 20% de O2, ou 20, 40, 60, 80% de CO2 com balanco de N2. As embalagens foram armazenadas por 30 dias a 26oC. As concentracoes de CO2 e O2 foram monitoradas dentro das embalagens durante o armazenamento. As analises de teor de umidade, acidez e pH foram tambem realizados no primeiro e trigesimo dia. Os resultados mostraram que no quinto, decimo quinto e trigesimo dia de estocagem nao foram encontrados diferencas significativas nas porcentagens de insetos mortos quando CO2 foi usado. Os resultados relativos a progenie indicaram que no quinto dia o numero de insetos emergentes foi menor a 20, 60 e 80% CO2. A completa inibicao dos insetos foi atingida com 30 dias de exposicao em atmosferas de CO2.

Development and characterization of phosphatidylcholine nanovesicles, containing garlic extract, with antilisterial activity in milk

Phospholipid nanovesicles were developed to improve the stability of garlic (Allium sativum L.) extract. Electron microscopy of liposomes revealed nanometric and spherical-shaped vesicles with a mean particle size of 174.6±17.3nm and polydispersity index of 0.26±0.02. The entrapment efficiency was 47.5±7.3% and the nanoliposomes had a zeta potential of -16.2±5.5mV. The antimicrobial activity of free and encapsulated garlic extract was evaluated against different strains of Listeria spp. in milk at 37°C for 24h. For free and encapsulated garlic extracts at 5% concentration, a decrease of 4log cycles in viable cell counts was observed at 10h, against four of the five strains of Listeria spp. tested. The results indicate that liposomes constitute a suitable system for encapsulation of unstable garlic active compounds and the encapsulation of garlic extract proves to be a promising technology for multiple applications, including antimicrobial agents.