The characteristics of reflectance spectrum of intact beef meat were numerically analyzed and the improved methodology for the assay of myoglobin was proposed. The new functions were derived from the parameter as the basis of denoted reciprocal reflectance whose numerical property corresponds to the K/S ratio of an absorption coefficient to a scattering coefficient. The proposal functions well agreed with meat color appearance and adjusted with the characteristic of the spectral pattern. Reflectance spectrum was measured with a rapid spectrophotometer and the data were immediately transferred to a small computer. Using this system, the relative proportions of oxygenated–, reduced– and met–myoglobin, and the psychophysical color values were calculated at real time. This method would be useful for not only quick quality control and evaluation of meat color appearance but also to monitor the biochemical aspects of myoglobin.

View full abstract

　Heat induced changes in the casein micelle structure were studied in cows' and buffalos' milk during prolonged boiling and the effects were correlated with the changes in their mineral balance and heat denaturation of whey proteins. More heat labile whey proteins and readily precipitable calcium in buffalos' milk resulted in prompt precipitation onto the micelle's surface and thus enhanced its early micellar coalescence. However, the heat degradation of the micelles were more severe in cows' milk to that of buffalos' milk for the same extent of heating. The heat fusion of the casein micelles were faster and severe in buffalos' milk leading early coagulation to that of cows' milk. Minerals like calcium and phosphorus played a significant role in this context. Sharp change in their soluble levels with concomitant precipitation as calcium-phosphate onto the casein micelles and reduction in pH values during heating would affected heat stability of milk. Buffalos' milk containing significantly higher levels of calcium and phosphorus showed higher calcium ion activity and faster precipitation during heatng, resulting lower heat stability than that of cows' milk.

View full abstract

　Standard plate counts (SPC) and colony forming units of psychrotrophic, mesophilic and thermoduric bacteria in raw milk produced from 1990 to 1992 in Hokkaido prefecture were determined twice a year (August and January, n=1,063).
The results were as follows ;
1. The average counts of each type were 26.9×10³/ml (SPC), 7.1×10³/ml (psychrotrophs), 18.7×10.3³/ml (mesophiles) and 1.9×10³ ml (thermodurics). The ratio of each type of bacteria to SPC were 26.4% (psychrotrophs), 69.5% (mesophiles) and 7.1% (thermodurics). The large numbers of bacteria cultured on standard plates seemed to contain both mesophiles and psychrotrophs.
2. The proportion of samples, equaling or exceeding particular count levels for each type of bacteria were as follows : SPC, 72.0% for ≦3×10⁴/ml and 97.5% for ≦1×10⁵/ml ; psychrotrophs, 67.9% for ≦ 5×10³/ml and 85.0% for ≦1×10⁴/ml ; mesopohiles, 83.3% for ≦3×10⁴/ml and 98.6% for ≦1×10⁵/ml ; and thermodurics, 67.3% for ≦1×10³/ml and 91.5% for ≦5x10³/ml.
3. Correlations between SPC and psychrotrophs, mesophiles and thermodurics were 0.469, 0.862 and 0.348, respectively. The highest correlation was recorded for mesophiles.

View full abstract