Effect of whey pretreatments on lactose recovery
Special Symposium - Innovations in Food Technology (LMC Congress)
Innovations in Food Technology - Poster Session (Food - P2)
Keywords: Whey, Protein Denaturation, Lactose, Crystallization
Whey is a by-product of the dairy industry whose major components are lactose, proteins and mineral salts. This is a heavy organic pollutant with high biological and chemical oxygen demand values. Lactose is responsible for 90% of the whey COD and BOD contents. On the other hand, lactose is a widely used ingredient for the food and pharmaceutical industries. So, lactose recovery is an important task both in environmental and in food sciences. The recovery of lactose from whey is generally accomplished by the simple process of concentration and crystallization. Preparation various grades of lactose generally include methods for removing whey proteins and ash components prior to crystallization.
Five pretreatments(acid-base, lime, Al2O3, Fecl3 and Alcl3 along with boiling), for removing whey protein and ash, are considered in this study . Whey after pretreatments was analyzed for lactose (With HPLC), ash, protein (With Kjeldhal Method) , Aluminium (Atomic absorbtion), Iron (Spectrophotometry) and Calsuim (Flame Photometry). Results show that best way for removal of protein is accomplished with adding HCl to change it's from pH 6 to 4, boiling 20 min, filtering protein aggregates. Also partial demineralization in whey solution for reducing ash is accomplished by adding NaOH to increase pH up 7.2 and heating solution for 20 min. After pretreatment, whey concentration was carried out in evaporator under vacuum at 62C. For lactose crystallization, a crystallizer which equipped with temperature controller and stirrer, is used. The stirring rate was fixed at 200rpm in all experiments and temperature program is: reducing temperature from 62C to 15C during one day and remaining at 15C for two days. Results show that removal of protein along with partial demineralization would improve lactose purity up to 99% from whey.
Presented Thursday 20, 13:30 to 14:40, in session Innovations in Food Technology - Poster Session (Food - P2).
