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FP06-2004
Food Science and Biotechnology in Developing Countries
Sorghum and Maize are the most used cereals but, these reported from 1990 to 1999 the 95%
of the supply needed for cattle intake. The preference for the consumption of this cereal is based on
the levels of supplies and price as well as the quality of energy that they provide
The demand of carcass, more young and light, indicate that the lambs are the most important
product 5 since they are being fed by nursing and concentrated, presenting muscles of clear or pinkish
color with little amount of fat (smaller than 3mm of thickness in the back), due to these characteristics
the carcass are considered of high quality. The systems of classification based on the weight and age
criteria imply an economic hierarchy of the carcass since influence in other characters exist like
greasing degree, consistency of the fat, flavor and aroma. 3,5,8
Numerous animals tissues are used as food since its structure is excessively complex, 3
consisting of a colloidal tissue, that contains from 55 to 78% of moisture, from 15 to 22% of proteins, 1
to 15% lipids, 1 to 2% of glucid and 1% of mineral salts. 9
The proteins are compounds that have become at the moment the main center of attention in
the world due to their importance, 10 that depends fundamentally on the content of essential amino
acids (necesary for life) and of their biological value. 11 The consumer demands meat with less fat, 12
that is to say meat with less saturated fat, since when consuming foods with higher energetic content
and low in fat have beneficial effects. 1,13 Fats are a concentrated source of energy, they provide
something more then twice of calories by gram then proteins and carbohydrates [9 over 4 Kcal/gr]. 4
Due to the demand that exists in this type of meat, the present study focused in the evaluation
of the quality of the meat of ovines Pelibuey and Rambouillet - Polipay, two species that have great
diffusion in the national field.
Material and methods
The present work was carried out in the Food Chemistry Laboratory (V203) of the Institute of
Biomedical Sciences, with the collaboration of the Cattle Department, both of the Autonomous
University of Ciudad Juarez.
Sample obtention from Longissimus dorsi
For the accomplishment of this work 16 lambs were used: 8 Pelibuey (P) and 8 Rambouillet-
Polipay (RP), that were distributed in individual corrals, as viewed in the figures 1 and 2.
Figure 1. Lamb Pelibuey Figure 2. Lamb Polipay-Rambouillet
The lambs were weaned after sixty days after birth, with a period of adaptation of fifteen days.
The food consumed was weighed twice a day every twelve hours. The food supplied increased when
the rejection was higher then 5% of the offered portion. Portion one was composed of: rolado maize,
alfalfa hay, harinolina, ammonium sulphate and a premixture of minerals. Portion two replaced maize
by sorghum. When the lambs reached an age of six months, they were sacrificed, previously
uninformed for twelve hours. The sacrifice was by decollation, with previous sensibilizacion.
After the sacrifice, the full digestive system, lungs, heart, liver, spleen, trachea, skin, legs and
head were weighed. Once the eviceration was concluded, the carcass was weighed, later cooled off to
4ºC during twenty-four hours.
The cold carcass was divided in longitudinal form in two equal parts, in one of the parts the
most important cuts were valued like: leg, thorax, arm-shoulder, abdomen and neck. One the right