ABSTRACT
Se caracterizaron dieciséis alimentos venezolanos de Humedad Intermedia (AHI) venezolanos de diferentes categorías, lácteos, cárnicos, marinos y de origen vegetal, tomando en cuenta, la actividad de agua, pH, humedad, acidez y humectantes utilizados. Paralelamente se estableció el perfil microbiano para cada AHI, siguiendo su evolución en función de las condiciones domesticas de almacenamiento y tiempo. Esta caracterización y comportamiento microbiano se relacionó con los obstaculos y nos permitió explicar los diferentes grados de estabilidad a temperatura ambiente de los AHI estudiados y sugerir mejoras que alarguen su vida útil. El valor de Aw, por sí solo, no es suficiente para garantizar la estabilidad del alimento si no es acompañado de un embalaje apropiado que limite las migraciones del agua, especialmente en nuestros países tropicales
Subject(s)
Food Microbiology , Food/classification , Chemical PhenomenaABSTRACT
Sixteen Venezuelan IMF, dairy products, dry-salted fish products, meat products and vegetable products (specially fruit products) were characterized; water activity, pH, moisture, acidity and humectants were determined, allowing us to identify the main hurdles. Parallelly the microbial profile and her evolution for each IMF were established in function of time and storage conditions. This information permits us to explain the different stability compartments for our IMF; simple modifications that will increase their stability are suggested. Water activity is not enough as a hurdle if it is not accompanied by an appropriate packaging, specially in tropical countries, that would limit water migrations.
Subject(s)
Food Microbiology , Food Preservation , Candy/analysis , Candy/microbiology , Dairy Products/analysis , Dairy Products/microbiology , Humidity , Meat Products/analysis , Meat Products/microbiology , Seafood/analysis , Seafood/microbiology , Time Factors , Wetting AgentsABSTRACT
The aim of this study was to prepare concentrated foods (20-40 p. 100 water), edible as such, chemically and microbiologically stable, nutritionally balanced, and which could be used as meal substitutes (travel, camping, snacks, etc.). With high methoxyl pectins, it was possible to obtain a pectic gel (pH 3,5), similar to a fruit jelly, but containing 20 p. 100 d.w. protein, and less sucrose. Water activity (Aw) was 0,75-0,78, for a 25 p. 100 water content, as a result of adding glucose syrup and sorbitol. After 4 months storage at 20 or 38 degrees C in aluminium pouches, no mold growth was detected (even following prior inoculation) nor practically any change in flavor, texture of Aw. With low methoxyl pectins, gel foods richer in water (35 p. 100), softer, less acid (pH 4,3) and containing even less sugars have been prepared (26 p. 100 d.w. protein, 35 p. 100 carbohydrates, 15 p. 100 lipids). Aw was lowered to 0,84 by adding humectants (sucrose, glycerol, sorbitol, citric acid, sodium citrate and chloride). Starch gels (40 p. 100 starch/d.w.), of pH less than 4,5, containing proteins and lipids, were flavored with vegetale powders. For 30 p. 100 water and with humectants, Aw was 0,84-0,88. The texture changes more or less favorably with time according to the nature of the starch used. Using the technology of processed cheeses, protein gels were made with either of the following characteristics: 1. A reduced Aw (0,86, for 38 p. 100 water) by adding humectants, but with a soft texture similar to that of a processed swiss cheese; 2. The same reduced Aw, with a starch content of 26 p. 100/d.w., and a harder texture, comparable to that of Emmenthal cheese.
