ABSTRACT
The purpose of this study was to evaluate the influence the use of homogenization of different proportions of milk--which allow to increase the yield in the process and probably to improve sensorial characteristics of the cheese--has on the ripening of low fat Chanco cheese. Five treatments (three replicates each) were studied, two corresponded to control (normal fat and low fat) and the other three treatments were low fat using partially homogenized milk in the following percentages of the total volume of milk; 12.5, 25 and 50 per cent. Standard methodology was used to monitor the evolution of ripening in terms of moisture, fat and total protein content, ripening index (NS/NT per cent), lipolysis (ADV), pH, sensorial quality and micro structure of the product. The low fat treatments with homogenized milk showed less fat losses in the whey and consequently increased yields. This study allowed us to know the low fat Chanco cheese maturation profile, low fat treatments with homogenisation showed a higher degree of lipolysis than the non--homogenized low-fat control although it was lower than normal fat control. No differences in terms of the development of proteolysis were observed. The low--fat homogenized treatments did not show improvement in the flavor neither in the cheese firmness probably due to the short ripening period (21 days) of this cheese variety, nevertheless T3 presented some advantages which could be improved applying simultaneously another technological helps.
Subject(s)
Dietary Fats/analysis , Food Handling/methods , Cheese/analysis , Chemistry, Physical , Humidity , Hydrogen-Ion Concentration , Time FactorsABSTRACT
The general use of refrigeration of raw milk has contributed to maintenance of its quality, but has induced the selection of a psychotrophic bacteria which during its growth produces heat-resistant enzymes responsible, in part, for the deterioration of long-life products. Given the condition of the prolonged refrigeration of the milk before the process, it was necessary to determine the growth curves for bacteria at temperatures between 2 degrees C and 10 degrees C and the kinetics of production of proteases in raw fresh milk, inoculated with Pseudomonas fluorescens RV1O, using an automatic fermentation system, with minimal agitation under conditions of controlled temperature and pH. The results show a development over 10(5) ufc/mL in the cultures at 6 degrees, 8 degrees and 10 degrees C during the first 30 h and proteasic activities over 30 microM p-NA/2 h getting levels of de 80-180 microM p-NA/2 h over 50 h of cultivation. Only the cultures at 2 degrees C appeared stable with inferior cell counts and without inducing enzymatic activity. At 4 degrees C an intermediate situation occurs.