Hiram Medrano-Roldán

Blue corn (Zea mays L.) with added orange (Citrus sinensis) fruit bagasse: novel ingredients for extruded snacks

Physicochemical and structural analyses were done of extruded snacks produced with two types of blue corn (hard and soft endosperm) combined with orange bagasse. Chemical composition, expansion index (EI), penetration force, water absorption index, and water solubility index values were calculated for all treatments. They were also analyzed with scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Addition of bagasse increased crude fiber content and hardness in the extrudates. It also lowered the EI, resulting in harder products with higher numbers of pores per area but of smaller sizes than in the extrudates without bagasse. Both the X-ray diffraction patterns and infrared spectra showed the starch to lose its semicrystalline structure due to mechanical shearing and high temperature. Orange bagasse was successfully incorporated into extrudated snacks made with blue corn of different endosperm hardnesses. Blue corn is a viable base for extruded snacks, and orange bagasse is a potential source of low cost, natural source fiber.

MICROENCAPSULACIÓN DE JUGO DE CEBADA VERDE MEDIANTE SECADO POR ASPERSIÓN MICROENCAPSULATION OF BARLEY GREEN JUICE BY SPRAY DRYING MICROENCAPSULACIÓN DE ZUME DE CEBADA VERDE MEDIANTE SECADO POR ASPERSIÓN

Abstract The barley green (BG) Hordeum vulgare L. is a plant with a high nutritive value. Spray drying (SD) has been used as a technique to encapsulate food materials, keeping its nutritional properties. The objective of this work was to evaluate the SD operation conditions to obtain microencapsulate BG powder. Parameters such as moisture content, color, proteins, sugars, minerals and, rehydration properties were determined. Juice from BG was obtained and maltodextrin was added as microencapsulating agent. The SD operation conditions were: inlet air temperature: 120, 140, and 160°C; maltodextrin concentration: 1, 3 and 5%, feed rate: 9, 11, and 13 ml/min; outlet air temperature ranged from 70 to 80°C. L*, a* and b* parameters in BG powder had significant differences with respect to juice. Due to inlet air temperatures statistical differences (p≤0.5, F=395.98), while the maltodextrin concentration and feed rate did not have statistical differences with respect to microencapsulate nutritive properties (p≥0.05). Statistical differences were found between treatments with respect to rehydratation properties, moisture content and temperature, so these were the most influencing parameters.

Detection of group I and group II introns in a Mexican Bacillus thuringiensis collection

Group I and II introns are non-coding sequences able to excise themselves from precursor mRNA by self-splicing. Both groups are ribozymes and may also code Open Reading Frames (ORF) for enzymes involved in the homing process; the Homing Endonuclease (HEase) in group I introns and maturase for group II. In this study, Mexican Bacillus thuringiensis strains belong to the Universidad Autonoma de Nuevo Leon collection were evaluated for the presence of these introns. For this propose, specific primers were designed for group I introns inserted in the ribonucleotide reductase operon and group II introns B.th.I, Bth.I2and B.th.I3. The PCR results obtained with primers for group I, was a DNA band of 600 bp for most strains (fifty four) and one of 200 bp for six one. The nucleotide sequence of 600 pb DNA band revealed more than 95% homology with the amplicons and group I introns reported before. Concern to group II introns, we can not see PCR products correspond to expect DNA band size.