Botanic garden response to the biodiversity crisis : implications for threatened species management.
Changes in intramuscular connective tissue brought about by conditioning were
investigated in bovine muscles of different quality. Perimysial and endomysial collagens
were solubilized to a small extent during conditioning and residual insoluble collagens in
both connective tissue domains were damaged by proteolytic processing.
Yields of soluble perimysial material from unconditioned muscles were significantly lower
(p = 0.096) than from conditioned muscles. Solubilized perimysial collagen from
unconditioned muscles was significantly lower (p = 0.015) than from conditioned muscles
with 1±0.8 % of original collagen solubilized for unconditioned muscles and 3.4 ± 3.3 %
for conditioned muscles. 87.5 % of the muscles examined showed an increase in
percentage solubilized collagen due to conditioning.
The main peptide components observed on analysis of insoluble perimysial fractions after
CNBr digestion were derived from types I and III collagen. No changes were observed
in the major peptide bands due to conditioning.
Yields of soluble endomysial fractions representedo, n average,9 4.5 % of total extracted
endomysial material for unconditioned muscles compared with 97.5 % for conditioned
muscles. Soluble endomysial fractions contained, on average, 0.13 % collagen from
unconditioned muscles and 0.22 % collagen from conditioned muscles.
The main peptide components observed on analysis of insoluble endomysial fractions after
CNBr-digestion were derived from types I and III collagen. Changes observed on the
peptide maps, evident as the appearanceo f a number of new bandsf rom conditioned
samples,a ppearedt o be muscle specific. % Type III collagen decreasedo n conditioning,
indicating that endomysial type III collagen was preferentially destroyed during
In model systems, insoluble perimysium treated with pepsin over 24 h resulted in little
damage to the insoluble collagenous residue remaining. Insoluble perimysium treated
with cathepsin resulted in changes to the major peptide bands on one-dimensional SDSpolyacrylamide
gel electrophoresisw hich were evident after 24 h treatment.
Two-dimensional peptide maps obtained from conditioned insoluble perimysium and from
insoluble perimysium treated with cathepsin for 24 h were altered relative to the
unconditioned insoluble perimysium, indicating proteolytic damage to high molecular
weight fractions. The in vitro case was extreme, but was comparable with conditioned insoluble perimysium. In addition, new peptide material in conditioned perimysium and
endomysium in the molecular weight range 40 000 to 50 000 was observed, while
perimysial samples revealed loss of peptide material, due to conditioning.
Percentage solubilized collagen was higher (p < 0.05) from three muscles of varying
quality when pre-injected with 0.1 M lactic acid and conditioned from 1 to 14 days than
from untreated muscles. Analysis of the high molecular weight collagen peptides from
lactic acid treated muscles by two-dimensional SDS-polyacrylamide gel electrophoresis
revealedi ncreasedin cidenceo f degradationi n this region comparedw ith untreated
Sensory profiling using quality descriptive analysis (QDA) was carried out on three
muscles of varying quality, pre-injected with 0.1 M lactic acid and results compared with
untreated muscles. The results obtained failed to correlate the observed biochemical
changes due to lactic acid treatment with perceived textural changes in these muscles.
However, variability of the taste panel scores contributed significantly to the results