Chemical and Technological Evaluation of Avocado Fruit Wastes for Enhancing Functional Properties of Some Foods

Avocado fruit is regarded as a super food rich in nutrients and phytochemicals. The present study focus on the evaluation of the waste of avocado fruits variety "Hass" (peels and seeds) for their nutritional and bioactive components. The results of proximate chemical composition revealed that nitrogen free extract (NFE) was the highest component in seeds and there were considerable amount of crude fiber (CF) in peels, where avocado peel powder (PPW) and seed powder (SPW) had 40.24 and 83.49% NFE and 40.36 and 4.20% CF, respectively. Both avocado peels and seeds could be considered a good source of macro and micro elements where potassium was the most abundant among macro elements (1445.03 and 2769.61 mg/100 g d.w), respectively, while Iron (8.84 and 13.40 mg/100 g d.w, respectively) was the most abundant among the micro-elements. The values of dietary fiber fractions of PPW and SPW could be ranked in descending orders as follows: neutral detergent fiber (NDF) (47.17 and 23.84%), acid detergent fiber (ADF) (40.39 and 7.15%), and acid detergent lignin (ADL) (17.26 and 3.52%), respectively. The results clearly demonstrated that seed contain significant higher amounts of total phenolic and flavonoid contents being 37.97 mg GAE/g and 18.94 mg QE/g, respectively where peel being 25.56 mg GAE /g and 13.65 mg QE /g, respectively. With regard to the antioxidant activity, seed extract exhibited the highest activity followed by peel extract. These results were confirmed with the IC50 and ABTS+ assays. Sensory evaluation revealed that avocado waste could be used in fortifying biscuits and beef burgersince all samples were accepted by the panelists. The most acceptable samples of biscuits were those containing 5 and 10 % of both SPW and PPW. As for beef burger, there were no significant differences for those containing 5% SPW followed by 5% PPW and still were accepted up to 10% SPW and 7.5% PPW and far from of limits rejection. In general the results showed that there was an improvement in the phenolics content and antioxidant activity of biscuits and beef burger with increasing the levels of SPW and PPW.