A Novel Strategy for Minimizing Acid Whey Generation during Greek Yoghurt Production

Greek yoghurt is thicker, creamier and surpasses regular yoghurt in terms of protein richness, flavour, texture and taste. Greek yoghurt attains this unique combination by incorporating straining at the end of the production process. However, such straining also generates whey with high lactic acid content, which can cause serious environmental problems unless properly disposed. Difficulties in post-process treatment of this whey stream still presents a main challenge for the industry although various approaches have been attempted. The necessity of developing techniques to reduce the acid whey production are thus importantly emphasized by the dairy industry. This present study aimed to explore an alternative strategy for Greek yoghurt production, which would reduce the amount of acid whey released. The main purpose of whey removal is to obtain desired concentration of total solids in the final Greek yoghurt. The proposed strategy thus aimed to increase the total solid level in initial milk base prior fermentation. This would potentially lead to lower levels of acid whey removal after fermentation. Therefore, the proposed technique would potentially provide a solution to the current acid whey issue. The study applied milk fortification and ultrafiltration techniques as two different approaches to obtain higher dry matter content of the initial milk base

Minimising generation of acid whey during Greek yoghurt manufacturing

Greek yoghurt, a popular dairy product, generates large amounts of acid whey as a by-product during manufacturing. Post-processing treatment of this stream presents one of the main concerns for the industry. The objective of this study was to manipulate initial milk total solids content (15, 20 or 23 g/100 g) by addition of milk protein concentrate, thus reducing whey expulsion. Such an adjustment was investigated from the technological standpoint including starter culture performance, chemical and physical properties of manufactured Greek yoghurt and generated acid whey. A comparison was made to commercially available products. Increasing protein content in regular yoghurt reduced the amount of acid whey during whey draining. This protein fortification also enhanced the Lb. bulgaricus growth rate and proteolytic activity. Best structural properties including higher gel strength and lower syneresis were observed in the Greek yoghurt produced with 20 g/100 g initial milk total solid compared to manufactured or commercially available products, while acid whey generation was lowered due to lower drainage requirement.</jats:p