ASSESSMENT OF AVOCADO (Persea americana MILL) SEED COMPOSITION AND IMPACT OF FUNGAL PATHOGENS ON THE FRUIT ROT AND SEED NUTRITION

Department of Plant Science and Biotechnology, Imo State University, Owerri, Nigeria.

Abstract

The growing trend of consuming raw avocado seeds, framed within sustainability and the principles of a circular economy, has prompted evaluation of avocado seeds nutritional value and potential to valorise the waste. This study evaluated the antinutrients of the avocado seed, assessed the fungi associated with avocado fruit deterioration, and the pathogenicity of the isolates. The antifungal activity of avocado seed extract, and the effects of the pathogens on the healthy and unhealthy seed proximate compositionsv were  determined. The results showed the percentage occurrence of fungi on avocado fruits, including Aspergillus niger (28.42 %), A. flavus (26.50 %), Rhizopus stolonifer (18.30 %), Botryodiplodia theobromae (14.35 %), and Fusarium oxysporum (12.43 %). Pathogenicity tests showed that all isolates except A. niger caused disease symptoms on inoculated fruit, including soft rot and browning. The strongest mycelial radial growth inhibition against the pathogens wasat 25mg/mL, seed extract concentration, with inhibition values for A. flavus(18.27mm),R. tolonifer(20.93mm), F. oxysporum (19.63mm), and Lasiodiplodia theobromae (23.33mm). Mancozeb produced stronger inhibition against the pathogens, than the extract. Healthy seeds had substantially higher proximate values (g/100 g) than
diseased seeds: carbohydrate 45.74 vs 11.38, crude fat 23.00 vs 5.33, protein 14.15 vs 3.45, ash 1.66 vs 0.34, and fibre 1.77 vs 0.35; moisture was higher in diseased seeds (17.34% vs 14.50%). Oxalate (5.11 mg/100 g) was the predominant antinutrient; phytate was lowest (0.31 mg/100 g). These findings demonstrate the potential of
avocado seed as a sustainable and eco-friendly solution for post harvest protection and waste valorisation.
Keywords: avocado seed, Antifungal, antinutrient, proximate, fungi.