Freezing/ thawing of sheep milk: alterations induced in milk, alternatives for minimize these modifications and impact in the yogurt production

Abstract

The production of dairy products from sheep's milk, especially yogurt, can be considered an interesting possibility for Brazilian family farming, adding value to their products. However, the little productivity per sheep obligates the small producer to freezing the milk during several days up to get sufficient volume to be processed. Although justifiable, milk freezing can reduces the protein stability, broken fat globules and modify the salt equilibrium. These alterations can affect the milk quality and negatively impacting in their dairy products. The usage of mixing and homogenization technologies can minimizes the undesirable effects induced by milk freezing/thawing, improving the protein dispersion and emulsifying the partially coalesced fat. Therefore, this project aims to evaluate: (i) the changes induced in the whole and skimmed sheep's milk by farming conditions of freezing/thawing, (ii) how mixing and homogenization process can minimizes the negative impacts caused by the freezing and (iii) how these process affects the yogurts characteristics. These results can be use as scientific background for specific law for sheep's milk in Brazil, help small producers the know and minimizes the impacts of milk freezing/thawing and, additionally, will help the scientific community the understand the biophysics alterations involved in the milk freezing/thawing and if and how is possible to restores this emulsion equilibrium using mixing and homogenization techniques. (AU)