Use of low degree of hydrolysis (DH < 10%) with enzymatic treatment can produce protein hydrolysates with functional properties superior to the raw material. Suspensions of Phaseolus lunatus protein isolate (PPI) were treated with one of two commercial enzymes (Alcalase or Flavourzyme) at 50°C and pH 8.0. DH with Alcalase was greater than Flavourzyme at 5 or 15 min of reaction. Alcalase-prepared hydrolysates had more peptides than those prepared with Flavourzyme. All the hydrolysates had higher solubility than the PPI, the highest being for the Alcalase-prepared hydrolysate at 15 min reaction time. Overall, the Alcalaseprepared hydrolysates had better solubility characteristics, whereas the Flavourzyme-prepared hydrolysates had better film properties (maximum emulsifying capacity and the highest foam formation values). This is probably because of the greater ease of movement toward the interface as shown by their high surface hydrophobicity values. The Alcalase-prepared hydrolysates had generally low or nonexistent film properties.

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Aim:  Development of a method for the isolation and purification of metagenomic RNA (mgRNA) from the ectopic bacterial flora of octopus. Methods and Results:  Modifications were made to the methods of Valenzuela‐Avendaño et al. (Plant Mol Biol Rep, 2005, 23, 199a) and Chomczynski and Sacchi (Anal Biochem, 1987, 162, 156) to develop a protocol based on chemical lysis with Trizol. This proposed protocol effectively isolated mgRNA. The resulting bacterial RNA transcripts were amplified with universal primers directed to the hypervariable regions of the 16S rRNA gene by complementary DNA synthesis. Protocol efficacy in the study of metabolically active bacterial flora was proven using DGGE, which produced a banding pattern that recovered sequences mainly related to the Vibrionaceae family. Conclusion:  The analysed samples were clearly complex, and the proposed protocol was proven to effectively isolate mgRNA from the metabolically active bacterial flora associated with octopus. Significance and Impact of the Study:  This is the first protocol proposed for the isolation of bacterial mgRNA that allows identification and study of metabolically active bacterial flora associated with octopus. This is an important step forward in understanding and controlling the microbial community of this economically important fishery resource, aimed at detecting its potentially pathogenic bacteria.

The objective of the present study was to construct a system that re-creates the conditions of fermentation and absorption of the human proximal colon. The model was constructed using a glass tube with an internal dialysis membrane tube. The food substrate was fed into the dialysis membrane three times a day simulating a typical human feeding. The substrate contained 58% carbohydrates, 35% proteins, 3% fiber, 3% starch, and 1% lipids on dry weight base, with 90% moisture. The inoculum was a fecal culture propagated in TSB. The intestinal absorption was simulated using a polyethylene glycol (PEG) solution running continuously outside the dialysis membrane. All microorganisms increased their counts after inoculation, and reached higher counts generally after substrate feed. The most important short chain fatty acids (SCFA: acetic, propionic and butyric acids) were analyzed, and their concentrations inside and outside the membrane were significantly different due to the extraction efficiency of the PEG solution. The greatest production occurred at 48 h. SCFA ratios showed that at the beginning, acetate was the predominant compound, but after 12 h the proportion of butyrate increased and the acetate was decreased. This SCFA production pattern is similar to that reported for the proximal colon in live systems. Continuous operation of the colon model for 48 h was enough to reveal the development of microorganisms and SCFA production. This model reproduced the conditions of the human proximal colon adequately and can be used to study the development of colonic microbiota.

Background: Octopus is a fishery product of economic importance worldwide, the main species caught on the coast of the Gulf of Mexico and the Caribbean Sea are Octopus maya and O. vulgaris, the first represents up to 95 % of national production. Goals: Identify the bacterial flora associated with commercial Octopus maya captured in the Yucatan Peninsula, using PCR-DGGE. Methods: From the metagenomic DNAs (mDNAs) extracted from samples representative of the octopus muscle, PCR products were synthesized with universal primers for bacteria (gc338F and 518R) and specific primers for Phylum Firmicutes (FirF: 369 and gcFirR: 1244). They were separated by electrophoresis in denaturing gradient gels (DGGE). The fragmented DNAs were recovered by elution, amplified (338F / 518R and FirF: 369 / FirR: 1244), sequenced and analyzed phylogenetically. Results: The sequences amplified with universal primers, after the DNA fragmentation by DGGE were associated with Psychrobacter urativorans, Psychrobacter sp, Pseudomonas sp, Pseudoalteromonas sp, Shewanella sp, Shewanella baltica, Klebsiella oxytoca, Vibrio aestuarianus, Photobacterium sp, Flavobacterium sp, F. antarcticum, Bizionia sp, Flavobacteriaceae bacterium, Bacillus sp, C. divergens, Cetobacterium somerae, Psychrilyobacter atlanticus, Salinimicrobium sp as well as, Flavobacteriaceae not yet classified. In the sequences amplified with specific primers (Phylum Firmicutes) were identified: Carnobacterium sp, Lactococcus piscium Lactococcus sp, and Vagococcus sp Conclusion: The bacterial genus detected have been reported in samples from marine environments; therefore, can be part of the native microbial diversity associated with commercial O. maya captured in the Yucatan Peninsula, Mexico.

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