EFFECT OF ADDITION OF YEAST AND OLD TIME FERMENTATION TO VOLUME DONAT

Abstract

This research is aimed at: 1) finding out the influence of increasing the amountof yeast and fermentation  time to the volume oj doughnuts, 2) finding  out the minimum amount of yeast effective in doughnut formula, and 3) finding out thelength of fermentation  time ideal for  each doughnut formula  with different percentage of yeast. The research uses experimental approach took place in the laboratory of Food Science, Department of Family Welfare Education, Faculty of Technology, Yogyakarta State University. Variables involved in this research consist of independent variables, i.e. different amount of yeast 1.1 %, 1.63%, and2.2%; length  of fermentation  time  45',  60',  75',  90',  105',  and  120';  and dependent variable  of the volume of doughnuts, controlling variable of thevolume of doughnuts beforefermentation. The mixing of ingredients to make the dough uses the straight dough method  The research is controlled by means of carefully scaling the ingredient using sartorial scale with the level of accuracy up to one milligram, standardizing the temperature while fermentation  and measuring the volume using the landscape method and. the data are analyzed further  by means  of  two-way Anava.  When any difference  is  obtained, the advanced-  test  Anava  is  performed  using  Duncan's  Multiple  Range  Test(DMRT). The result of the research shows that: 1) there is significant difference of  the  doughnut  volume  based  on  various  amount  of yeast  and  length  of fermentation  time; 2) 1.1% of yeast  is still effective to enlarge the volume of doughnuts without any significant difference based on the analysis of DMRT on the three different formulations with 90-minutefermentation  time, and thus the ideal fermentation  time for  the three formulation  tested is 90 minutes because over 90 minutes the dough will have got over proofing.