Phenolic extracts of carrot, grape leaf and turmeric powder: antioxidant potential and application in biscuits

Natural antioxidants have gained interest for their role in preventing lipids oxidation. The goals of this investigation were to study the antioxidant potential of carrot (Daucus carota), grape (Vitis vinifera) leaf and turmeric (Curcuma longa) powder extracts and to evaluate their addition as natural antioxidants in biscuits. Physical and chemical properties of biscuit were evaluated during processing and storage. Electrophoretic properties of biscuit dough were carried out to understand the impact of different extracts on the processing of biscuits. Biscuits prepared with 1 % (w/w) grape leaves ethanol (70 %) extract (GLE), carrot aqueous extract (CE), and tumeric aqueous extract (TE) were acceptable. Among extracts, TE was found to retain only 11.2 % activity, wherein GLE had retained 51.0 % activity after baking, which was comparable to butylated hydroxyanisole and better than tert-butylhydroquinone (TBHQ). TBHQ was found to possess the highest activity, followed by GLE, TE and CE, respectively. The ash content of biscuits enriched with TE and GLE was near to that of the control sample. Addition of CE, GLE and TBHQ reduced the force required for breakage. After 15 days of storage, PV was increased in all samples, but in the case of GLE-enriched sample there was a sudden increase in PV from 0.034 to 0.374. Supportive electrophoresis study indicated that there was no change in the protein subunits of biscuit dough fro different samples. It could be concluded that GLE, CE and TE might be used in biscuit baking as natural antioxidants.