Alfonso Totosaus

Evaluation of thermotolerant capacity of lactic acid bacteria isolated from commercial sausages and the effects of their addition on the quality of cooked sausages

The thermotolerant capacity of several lactic acid bacteria strains isolated from cooked commercial sausages was determined. Four strains were positively identified as Lactobacillus plantarum, Lactobacillus curvatus, Pediococcus pentosaceus and Pediococcus acidilacti, after surviving thermal treatment (70 °C during 60 minutes). Thermotolerant strains were inoculated in sausage batters before cooking in order to determine their effect on color, texture, acceptance and inhibition of Enterobacteria during 12 days at 8 °C. No significant effect of the inoculated strains was detected on color parameters. Textural profile parameters, cohesiveness and resilience, were not affected by the inoculation of thermotolerant lactic acid bacteria, but L. curvatus sausages resulted softer than the rest of the treatments. Samples inoculated with L. curvatus also obtained the lowest scores for the sensory attributes evaluated, with the remaining treatments causing no unfavorable effects on sausage acceptance. There was a reduction in enterobacterial counts after 12 days of cold storage in inoculated samples. The performance of inoculated lactic acid bacteria strains can be explained in a similar way as that of starter cultures in dry-fermented sausages, where the growth in nests impairs other pathogenic microorganisms present in the rest of the sausage, since environmental conditions and the early inoculation of these thermotolerant strains favor them to become the dominant flora.

Improvement of Moisture Stability and Textural Properties of Fat and Salt Reduced Cooked Sausages by Inoculation of Thermotolerant Lactic Acid Bacteria

Four thermotolerant lactic acid bacteria strains (UAM15c, UAM10a, UAM17, UAM18) were inoculated in two cooked sausage formulations (one full fat and sodium and one fat-sodium reduced). Total moisture content, expressible moisture and cooking stability, pH and CIE-Lab color, and texture were evaluated during 15 days of storage at 4°C. Inoculation improved cooking stability and reduced water release in both formulations, resulting as well in lighter and less red and yellow coloration. Inoculation of thermotolerant lactic acid bacteria resulted in less hard and more cohesive texture. Microscopy showed that P. acidilacti UAM15c and L. plantarum UAM10a secreted exopolysaccharides probably related to high moisture stability and better textural properties, as compared with non-inoculated samples.

Optimization of fat-reduced ice cream formulation employing inulin as fat replacer via response surface methodology

The use of new ingredients like inulin for fat replacement is of wide application in the food industry. The aim of the present work was to reduce the fat content on ice cream formulations. It was possible to reduce up to 25% of butyric and vegetable fats with 3% of inulin, with good textural and sensory characteristics of the final product. The substitution of fat with inulin increased the ice cream mix viscosity, improved air incorporation, and produced ice cream with soft and homogeneous textures. Color characteristics were not affected by the replacement. Hedonic sensory analysis showed that optimized fat-reduced inulin ice cream was not perceived different to commercial vanilla ice cream.

Efecto del pH y de la adición de fosfatos de sodio sobre las propiedades de gelificación y emulsión de surimi de trucha arco-iris (Oncorhynchus mykiss)

Para la elaboracion de surimi se han empleado distintas tecnicas, sin embargo, es indispensable mantener la funcionalidad de las proteinas musculares durante su extraccion, ya que son afectadas principalmente por el pH. La incorporacion de fosfatos en productos carnicos afecta el pH, teniendo como consecuencia una mejora en la capacidad de retencion de agua de las proteinas musculares, alterando la funcionalidad de estos productos. Se utilizo la metodologia de superficie de respuesta para determinar el efecto de cinco niveles de pH y cinco concentraciones de una mezcla de fosfatos de sodio comercial sobre la funcionalidad de surimi de trucha arco-iris, evaluada por su capacidad de emulsion y trabajo de emulsion, fuerza de gel y trabajo de penetracion de geles de surimi. Los resultados obtenidos indican que el incremento en la concentracion de fosfatos de sodio mejoro la funcionalidad del surimi y a pH alcalino las propiedades de emulsion mejoraron, pero se afectaron negativamente las propiedades de gelificacion.

Emulsifying Properties of Food Proteins Conjugated with Glucose or Lactose by Two Methods (Spray-Drying Or Freeze-Drying)

Emulsifying properties of two commercial food proteins (plasma protein or egg albumen) conjugated with two sugars (glucose or lactose) by spray-drying or lyophylization were studied. Changes in protein structure were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, sulfhydryl group, Fourier transform infrared spectroscopy and differential scanning calorimetry, emulsion properties (emulsion capacity and stability, emulsion work, and emulsifying activity index). Protein conjugation increased proteins molecular weight and decreased sulfhydryl groups, coinciding with lower denaturation enthalpies, corroborating structural changes by conjugation with glucose or lactose by either spray-drying or freeze-drying. Glucose conjugation of the proteins employed at the experimental conditions resulted in structural changes that emulsify more oil with no detrimental effect on emulsion superficial area formation. Although freeze-drying conjugation improved emulsifying properties, spray-drying also enhanced these properties, as compared to non-conjugated proteins. Spray-drying was a faster way to conjugate food proteins via Maillard reaction with improved emulsifying properties.

Interaction Between Caseinate and Carrageenans Results in Different Physical and Mechanical Properties of Edible Films

Abstract Edible films were elaborated with sodium caseinate and different types of carrageenans (iota, kappa or lambda), and glycerol as plasticizer, to determine the different specific interactions between caseinate and carrageenans on physical and mechanical properties via a response surface methodology approach. The different sulphate groups content in the different carrageenans affected differentially edible films properties. The use of lambda carrageenan in edible film formulation resulted in more soluble and permeably film, with a concomitantly both less rigid and more elastic structure. The edible film formulation was optimized to 8.0 % of caseinate, 0.4% of carrageenan (irrespectively of the type) and 0.3% of glycerol.

Evaluation of Agro-Industrial Co-Products as Source of Bioactive Compounds: Fiber, Antioxidants and Prebiotic

Abstract Agro-industrial co-products derived of fruit processing represents an important source of bioactive compounds as fiber, antioxidants and prebiotics. The objective of this work was to determine the content of fiber, antioxidant capacity and prebiotic activity of three flours obtained from commonly co-products (banana peel, apple peel, and carrot bagasse). The results showed a higher total fiber content in carrot bagasse, and lower in apple peel. Significantly differences were found in antioxidant activity. Fruit co-products flours were a suitable carbon source increasing specific growth rate with a reduction in duplication time as compared to glucose. The prebiotic activity was positive in the three co-products, all flours survived at pH 1.0 and showed resistance to simulated gastric acid for about 60 min. Banana peel, apple peel and carrot bagasse showed to be a good source of bioactive compounds as fiber and antioxidants and can be used as prebiotics for lactic acid bacteria.