Introduction
Deep-fried donuts are one of the most popular fried foods, but their high oil content (15–30%) is problematic. The use of natural hydrocolloids is effective for oil reduction. Kombucha (fermented tea) contains bacterial cellulose that can be hydrolyzed and used as a hydrocolloid. This study investigated the efficacy of kombucha cellulose hydrolysate in reducing oil in donuts.
Materials and Methods
Production of kombucha cellulose hydrolysate Kombucha cellulose was produced from fermented black tea culture with Acetobacter bacteria. It was then hydrolyzed by enzymatic method (cellulase) or microwave (500 W, 10 min).
Donut formula 100 g whole wheat flour, 20 g sugar, 1.5 g salt, 2 g yeast, 15 g butter, 1 egg, 60 ml milk + 0–3% hydrolysate.
Frying and measurements Frying at 180°, texture analysis with TPA, oil absorption measurement with Soxhlet, microscopic structure with SEM.
Results and discussion
1. Water and oil holding capacity (Table 1) Microwave hydrolysate had higher water holding capacity (19.2 g/g) and lower oil absorption (6.1 g/g).
2. Oil absorption of donuts (Figure 3) Adding 2% microwave hydrolysate reduced oil absorption from 15.3 to 10.9% (28.1% reduction).
3. Texture and structure (Figure 4) Donuts with hydrolysate had a softer texture and a less porous structure that prevented oil absorption.
Conclusion
Kombucha cellulose hydrolysate (especially the microwave type) can be an effective alternative for reducing oil in donuts. This method is recommended for the production of healthier foods.
