Fermentation of liquid coproducts and liquid compound diets: Part 2. Effects on pH, acid-binding capacity, organic acids and ethanol during a 6-day storage period

The effects of a 6-day storage period on changes in pH, acid-binding capaci ty, level of organic acids and ethanol of three liquid coproducts [liquid w heat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW)] and two liquid compound diets [liquid grower diet (LGD) and liquid finisher di et (LFD)] were studied. All products, except LWS showed a significant decre ase in pH and acid-binding capacity during storage. At the end of the stora ge period, all products reached a pH of between 3.5 and 3.9. In general, it can be concluded that the lactic acid content, and to a lesser L stent the acetic acid content, increased dramatically during storage. In contrast, t he ethanol content increased significantly in the liquid compound diets onl y. The pattern of changes in pH and organic acids during the 6-day storage period was difference between the liquid coproducts and the liquid compound diets. At the start of storage, liquid coproducts are already in the 'midd le' of the fermentation process, while liquid compound diets need approxima tely 24-36 h before fermentation begins. Consequently, in practice a differ ent approach to obtain fermented diets is needed for liquid coproducts and liquid compound diets.