Premium
Impact of sterilization and storage on the properties of concentrated skim milk by cryoconcentration in comparison with vacuum evaporation and reverse osmosis concentration
Author(s) -
Balde Alseny,
Aider Mohammed
Publication year - 2019
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/jfpe.13130
Subject(s) - skimmed milk , reverse osmosis , chemistry , sterilization (economics) , food science , evaporation , membrane , biochemistry , physics , monetary economics , economics , foreign exchange market , thermodynamics , foreign exchange
The aim of this study was to compare the impact of sterilized skim milk after being concentrated by three concentration techniques; namely cryoconcentration, vacuum evaporation, and reverse osmosis. To achieve this objective, skim milk was concentrated up to 18% total dry matter by cryoconcentration, vacuum‐evaporation and reverse osmosis, heat sterilized, and stored during 3 months. The obtained results showed that the surface net charge of the proteins in milk concentrated by vacuum evaporation decreased during storage, while that of the other milks remained stable. The levels of free amino acids decreased as a function of the storage time for the three skim milk samples with a higher rate for the vacuum evaporated milk. Thiol groups were affected by sterilization, but remained stable during storage. After sterilization, the consistency coefficient of milk increased by 8.6, 2.25, and 2.35 times for evaporated milk, concentrated by reverse osmosis, and cryoconcentrated, respectively. This result indicated a more stability of sterilized cryoconcentrated skim milk in comparison with the other skim milk samples which showed a tendency to age thickening. Practical Applications The findings of this research work can be applied by the dairy industry to produce concentrated skim milk following a cryoconcentration procedure. This subzero concentrating technique can substitute vacuum evaporation and reverse osmosis. The advantage of cryoconcentration, as used in this work, is its low energy consumption and high product quality. Indeed, because of the low latent heat of freezing of water in comparison with its latent heat of vaporization (seven times lower), cryoconcentration is an effective energy saving technology. Thus, the dairy processing industry can exploit the advantages of cryoconcentration to develop novel dairy foods and to save energy.