Pectin extraction from apple pomace (Malus domestica) as gelatin replacer using living cells with ultrasound pretreatment

One way to support the achievement of food self-sufficiency is to utilize the potential of existing domestic resources, for example, by using apple pomace as a raw material for pectin production. Imports meet the need for pectin due to Indonesia’s absence of a pectin processing industry. So far, apple pomace has only been used as animal feed and biofuel, whereas in apple pomace, there are still many pectins that can replace the role of gelatin in the food industry. Pectin is a complex polysaccharide that composes plant cell walls, usually found in the middle lamella and the primary cell wall, which is bound to cellulose and hemicellulose. This study extracted pectin using live cells of Aspergillus niger and Trichoderma reesei through solid-state fermentation. The combination of the two microbes produces cellulase enzymes with the best composition. Ultrasound pretreatment was used to optimize the enzyme’s penetration into the apple pomace’s cell wall. This study was designed using one-factor-at-a-time (OFAT) optimization with three factors: the concentration of addition of molasses (0%, 6%, and 18%), the ratio of spores (1:1, 5:1, and 1:5), and the delay time of inoculation (0, 1, 2, and 3 days). The addition of 6% molasses concentration, spore ratio of T. reesei: A. niger of 5:1, two days delay time inoculation, and six-day fermentation obtained the optimum result in terms of the galacturonic acid content and yield, 43.38±0.29% and 14.52±0.48%, respectively.