EFFECTS OF THERMAL PROCESSING ON THE ANTIOXIDANT CAPACITY IN NUTS AND SEEDS
Pedro Rebollar Jr., Kwok-Tuen (Raymond) Tse.
1DePaul University, Chicago, IL, 2Harold Washington College, Chicago, IL.
Epidemiological studies have suggested a positive association between the consumption of foods with antioxidant properties and their possible role in preventing chronic degenerative diseases. With antioxidants becoming more and more common within the food industry, this study evaluates how much antioxidant levels increase in nuts and seeds when they are processed with heat. The hypothesis for this experiment was that a nut in a raw natural state will have a higher antioxidant capacity compared to its roasted state. The TEAC (Trolox equivalent antioxidant capacity) method was incorporated to evaluate the antioxidant capacity of 5 different nuts and seed samples: pecan, walnut, sunflower seed, almond, and cashew. The TEAC method assesses the ability to scavenge stable radical cation, ABTS+, by comparing an ABTS and antioxidant nut solution against our Trolox standard, a water-soluble vitamin E analogue. Antioxidants in the nut milk sample, created by blending soaked nuts and seeds in water, were extracted using methanol as a solvent. The absorbance of the extract was then measured using a spectrophotometer set at a wavelength of 734 nm. The results were compared to a calibration curve that was constructed using Trolox as a standard. The percent change of antioxidant capacity was calculated from a raw state to a roasted state (230 ˚C at 15 min). The results indicated the following percent increase in antioxidant level: pecan-281.4%, almond-186.1%, cashew-159.6%, walnut-156.8%, and sunflower seed-118.7%. This study indicates that roasting nuts and seeds increases their antioxidant capacity.