Production run time impacts quality of skim milk powder.
The sensory and functional qualities of skim milk powder (SMP) influence the use and consumer acceptance of powdered milk in various applications.
Previous research has shown that the flavor variability found in low-heat skim milk powder can impact consumer acceptance involving ingredient applications. We've also learned from past research that microbiological quality decreases with longer manufacture run times before equipment is cleaned.
Scientists at North Carolina State University investigated the impact of production run time on the sensory, microbiological and functional properties of skim milk powder. After using six different domestic spray-drying facilities for the sampling of low- and medium-heat skim milk powder, they found that as the production run time increases, the sensory, microbial and functional quality of skim milk powder deteriorates. Relating run time to skim milk powder quality can provide manufacturers with the information they need to improve the quality of the powder.
The researchers selected samples that included milk concentrate from the last evaporator effect, which contained 50% solids, and spray-dried powder after production runs of 0, 12, 24 and 36 hours. The scientists performed microbiological and flavor property analyses--sensory and instrumental volatile analyses--on both the concentrated milk and powder.
Coliforms, aerobic bacteria and aerobic thermophilic sporeformers were enumerated. Surface free fat, particle size, solubility, viscosity, furosine and the whey protein nitrogen index were analyzed. Results were evaluated using statistical techniques.
The results were consistent across the various production facilities. An increase in production run times increased aroma and cooked-sulfur flavor intensities and decreased sweet aromatic flavor in the skim milk powder. Volatile compound results were consistent with sensory profiles. Higher sulfur volatiles and decreased sweet aromatic compounds--2 acetyl pyrroline, ethyl maltol--appeared with increased run times.
Microbial counts--aerobic thermophilic spores, total aerobic plate counts--increased, and solubility also decreased with run times. Particle size, viscosity and furosine were not affected by production run times.
Further information. Maryanne Drake, Department of Food Science, 236-E Schaub Hall, Box 7624, North Carolina State University, Raleigh, NC 27695; phone: 919-513-4598; email: email@example.com.
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|Publication:||Emerging Food R&D Report|
|Date:||Jan 1, 2016|
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