Produção de xarope de lactulose a partir do soro de ricota e seu emprego em iogurte e queijo Quark

Abstract

One of the biggest problems faced by the dairy product sector throughout the world it is the destination given to the whey originating the from cheese production. The milk serum is a by-product of the dairy product industry that is awakening the the interest of countless researchers all over the world due to its nutritional, functional and economic potential. For being a residue that presents high organic matter it can contaminate receiving bodies, generating serious environmental problems. This fact justifies all of the efforts undertaken to avoid it is released in water courses, as has been happening since the beginning of cheese production in Brazil. New applications for the whey are a real necessity for the dairy industry, since they can work within the demands of the environmental protection agencies. The whey can be destined for the production of a substance with functional properties; lactulose; through an isomerization reaction where the lactose is converted into lactulose. Currently, lactulose has been widely used in the food industry, with prominence in the dairy products sector. It is claimed thet lactulose presents prebiotic properties, being able to stimulate the growth of probiotic microorganisms in the large intestine, which can promote desirable reactions. This work was conducted with the objective of producing a lactulose syrup starting from ricotta whey and to use this syrup in symbiotic milk products such as yogurt and quark (curd) cheese. The purification of the lactulose syrup was carried out in ion exchange and molecular exclusion chromatographic columns, this purification occurred for the removal of the boric acid (catalyst). After the purification of the lactulose syrup in the chromatographic columns, thin layer chromatography (TLC) was used, which was efficient for the lactulose detection. To confirm the lactulose synthesis in the syrup, high performance liquid chromatography (HPLC) was conducted where the lactose isomerization reaction can be confirmed in lactulose. The effect of the lactulose percentage on the sensorial quality of yogurt and quark cheese was evaluated, both added with probiotic cultures. The results indicated that, after the purification of the lactulose syrup in ion exchange and molecular exclusion columns, lactulose presence or similar compound fractions were identified by thin layer chromatography. The lactulose synthesis was confirmed through high performance liquid chromatography, the yield obtained was approximately 58%. By ANOVA and test of averages, a high acceptability of the yogurt and quark cheese with added lactulose was observed. For the yogurt, just for the attribute, appearance, there was significant difference (p ≤ 0,05) among the samples. The quark cheese did not present significant difference (p ≤ 0,05) among the samples.