Application of central composite design in the fermentation of apple pomace to optimize its nutritional and functional properties

Simultaneous optimization of protein, soluble and insoluble dietary fibre, total phenolic content, and antioxidant activity was carried out in apple pomace by using response surface methodology (RSM) and solid state fermentation. A central composite design (CCD) was used to optimize the content of nutritional and functional properties, and two factors were studied: time and temperature of fermentation. The fermentation of apple pomace under the best conditions (29.5 ºC and 4.9 days) allowed the depletion of fermentable sugars, an increase the contents of protein and insoluble dietary fibre (36% and 23%, respectively), while soluble dietary fibre, total phenolic content, and antioxidant activity remained constant